use super::traits::{Channel, ChannelMessage, SendMessage};
use crate::config::Config;
use crate::security::pairing::PairingGuard;
use anyhow::Context;
use async_trait::async_trait;
use directories::UserDirs;
use parking_lot::Mutex;
use reqwest::multipart::{Form, Part};
use std::fs;
use std::path::Path;
use std::sync::{Arc, RwLock};
use std::time::Duration;

/// Telegram's maximum message length for text messages
const TELEGRAM_MAX_MESSAGE_LENGTH: usize = 4096;
const TELEGRAM_BIND_COMMAND: &str = "/bind";

/// Split a message into chunks that respect Telegram's 4096 character limit.
/// Tries to split at word boundaries when possible, and handles continuation.
fn split_message_for_telegram(message: &str) -> Vec<String> {
    if message.len() <= TELEGRAM_MAX_MESSAGE_LENGTH {
        return vec![message.to_string()];
    }

    let mut chunks = Vec::new();
    let mut remaining = message;

    while !remaining.is_empty() {
        let chunk_end = if remaining.len() <= TELEGRAM_MAX_MESSAGE_LENGTH {
            remaining.len()
        } else {
            // Try to find a good break point (newline, then space)
            let search_area = &remaining[..TELEGRAM_MAX_MESSAGE_LENGTH];

            // Prefer splitting at newline
            if let Some(pos) = search_area.rfind('\n') {
                // Don't split if the newline is too close to the start
                if pos >= TELEGRAM_MAX_MESSAGE_LENGTH / 2 {
                    pos + 1
                } else {
                    // Try space as fallback
                    search_area
                        .rfind(' ')
                        .unwrap_or(TELEGRAM_MAX_MESSAGE_LENGTH)
                        + 1
                }
            } else if let Some(pos) = search_area.rfind(' ') {
                pos + 1
            } else {
                // Hard split at the limit
                TELEGRAM_MAX_MESSAGE_LENGTH
            }
        };

        chunks.push(remaining[..chunk_end].to_string());
        remaining = &remaining[chunk_end..];
    }

    chunks
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum TelegramAttachmentKind {
    Image,
    Document,
    Video,
    Audio,
    Voice,
}

#[derive(Debug, Clone, PartialEq, Eq)]
struct TelegramAttachment {
    kind: TelegramAttachmentKind,
    target: String,
}

impl TelegramAttachmentKind {
    fn from_marker(marker: &str) -> Option<Self> {
        match marker.trim().to_ascii_uppercase().as_str() {
            "IMAGE" | "PHOTO" => Some(Self::Image),
            "DOCUMENT" | "FILE" => Some(Self::Document),
            "VIDEO" => Some(Self::Video),
            "AUDIO" => Some(Self::Audio),
            "VOICE" => Some(Self::Voice),
            _ => None,
        }
    }
}

fn is_http_url(target: &str) -> bool {
    target.starts_with("http://") || target.starts_with("https://")
}

fn infer_attachment_kind_from_target(target: &str) -> Option<TelegramAttachmentKind> {
    let normalized = target
        .split('?')
        .next()
        .unwrap_or(target)
        .split('#')
        .next()
        .unwrap_or(target);

    let extension = Path::new(normalized)
        .extension()
        .and_then(|ext| ext.to_str())?
        .to_ascii_lowercase();

    match extension.as_str() {
        "png" | "jpg" | "jpeg" | "gif" | "webp" | "bmp" => Some(TelegramAttachmentKind::Image),
        "mp4" | "mov" | "mkv" | "avi" | "webm" => Some(TelegramAttachmentKind::Video),
        "mp3" | "m4a" | "wav" | "flac" => Some(TelegramAttachmentKind::Audio),
        "ogg" | "oga" | "opus" => Some(TelegramAttachmentKind::Voice),
        "pdf" | "txt" | "md" | "csv" | "json" | "zip" | "tar" | "gz" | "doc" | "docx" | "xls"
        | "xlsx" | "ppt" | "pptx" => Some(TelegramAttachmentKind::Document),
        _ => None,
    }
}

fn parse_path_only_attachment(message: &str) -> Option<TelegramAttachment> {
    let trimmed = message.trim();
    if trimmed.is_empty() || trimmed.contains('\n') {
        return None;
    }

    let candidate = trimmed.trim_matches(|c| matches!(c, '`' | '"' | '\''));
    if candidate.chars().any(char::is_whitespace) {
        return None;
    }

    let candidate = candidate.strip_prefix("file://").unwrap_or(candidate);
    let kind = infer_attachment_kind_from_target(candidate)?;

    if !is_http_url(candidate) && !Path::new(candidate).exists() {
        return None;
    }

    Some(TelegramAttachment {
        kind,
        target: candidate.to_string(),
    })
}

/// Strip tool_call XML-style tags from message text.
/// These tags are used internally but must not be sent to Telegram as raw markup,
/// since Telegram's Markdown parser will reject them (causing status 400 errors).
fn strip_tool_call_tags(message: &str) -> String {
    let mut result = message.to_string();

    // Strip <tool>...</tool>
    while let Some(start) = result.find("<tool>") {
        if let Some(end) = result[start..].find("</tool>") {
            let end = start + end + "</tool>".len();
            result = format!("{}{}", &result[..start], &result[end..]);
        } else {
            break;
        }
    }

    // Strip <toolcall>...</toolcall>
    while let Some(start) = result.find("<toolcall>") {
        if let Some(end) = result[start..].find("</toolcall>") {
            let end = start + end + "</toolcall>".len();
            result = format!("{}{}", &result[..start], &result[end..]);
        } else {
            break;
        }
    }

    // Strip <tool-call>...</tool-call>
    while let Some(start) = result.find("<tool-call>") {
        if let Some(end) = result[start..].find("</tool-call>") {
            let end = start + end + "</tool-call>".len();
            result = format!("{}{}", &result[..start], &result[end..]);
        } else {
            break;
        }
    }

    // Clean up any resulting blank lines (but preserve paragraphs)
    while result.contains("\n\n\n") {
        result = result.replace("\n\n\n", "\n\n");
    }

    result.trim().to_string()
}

fn parse_attachment_markers(message: &str) -> (String, Vec<TelegramAttachment>) {
    let mut cleaned = String::with_capacity(message.len());
    let mut attachments = Vec::new();
    let mut cursor = 0;

    while cursor < message.len() {
        let Some(open_rel) = message[cursor..].find('[') else {
            cleaned.push_str(&message[cursor..]);
            break;
        };

        let open = cursor + open_rel;
        cleaned.push_str(&message[cursor..open]);

        let Some(close_rel) = message[open..].find(']') else {
            cleaned.push_str(&message[open..]);
            break;
        };

        let close = open + close_rel;
        let marker = &message[open + 1..close];

        let parsed = marker.split_once(':').and_then(|(kind, target)| {
            let kind = TelegramAttachmentKind::from_marker(kind)?;
            let target = target.trim();
            if target.is_empty() {
                return None;
            }
            Some(TelegramAttachment {
                kind,
                target: target.to_string(),
            })
        });

        if let Some(attachment) = parsed {
            attachments.push(attachment);
        } else {
            cleaned.push_str(&message[open..=close]);
        }

        cursor = close + 1;
    }

    (cleaned.trim().to_string(), attachments)
}

/// Telegram channel — long-polls the Bot API for updates
pub struct TelegramChannel {
    bot_token: String,
    allowed_users: Arc<RwLock<Vec<String>>>,
    pairing: Option<PairingGuard>,
    client: reqwest::Client,
    typing_handle: Mutex<Option<tokio::task::JoinHandle<()>>>,
}

impl TelegramChannel {
    pub fn new(bot_token: String, allowed_users: Vec<String>) -> Self {
        let normalized_allowed = Self::normalize_allowed_users(allowed_users);
        let pairing = if normalized_allowed.is_empty() {
            let guard = PairingGuard::new(true, &[]);
            if let Some(code) = guard.pairing_code() {
                println!("  🔐 Telegram pairing required. One-time bind code: {code}");
                println!("     Send `{TELEGRAM_BIND_COMMAND} <code>` from your Telegram account.");
            }
            Some(guard)
        } else {
            None
        };

        Self {
            bot_token,
            allowed_users: Arc::new(RwLock::new(normalized_allowed)),
            pairing,
            client: reqwest::Client::new(),
            typing_handle: Mutex::new(None),
        }
    }

    fn normalize_identity(value: &str) -> String {
        value.trim().trim_start_matches('@').to_string()
    }

    fn normalize_allowed_users(allowed_users: Vec<String>) -> Vec<String> {
        allowed_users
            .into_iter()
            .map(|entry| Self::normalize_identity(&entry))
            .filter(|entry| !entry.is_empty())
            .collect()
    }

    fn load_config_without_env() -> anyhow::Result<Config> {
        let home = UserDirs::new()
            .map(|u| u.home_dir().to_path_buf())
            .context("Could not find home directory")?;
        let zeroclaw_dir = home.join(".zeroclaw");
        let config_path = zeroclaw_dir.join("config.toml");

        let contents = fs::read_to_string(&config_path)
            .with_context(|| format!("Failed to read config file: {}", config_path.display()))?;
        let mut config: Config = toml::from_str(&contents)
            .context("Failed to parse config file for Telegram binding")?;
        config.config_path = config_path;
        config.workspace_dir = zeroclaw_dir.join("workspace");
        Ok(config)
    }

    fn persist_allowed_identity_blocking(identity: &str) -> anyhow::Result<()> {
        let mut config = Self::load_config_without_env()?;
        let Some(telegram) = config.channels_config.telegram.as_mut() else {
            anyhow::bail!("Telegram channel config is missing in config.toml");
        };

        let normalized = Self::normalize_identity(identity);
        if normalized.is_empty() {
            anyhow::bail!("Cannot persist empty Telegram identity");
        }

        if !telegram.allowed_users.iter().any(|u| u == &normalized) {
            telegram.allowed_users.push(normalized);
            config
                .save()
                .context("Failed to persist Telegram allowlist to config.toml")?;
        }

        Ok(())
    }

    async fn persist_allowed_identity(&self, identity: &str) -> anyhow::Result<()> {
        let identity = identity.to_string();
        tokio::task::spawn_blocking(move || Self::persist_allowed_identity_blocking(&identity))
            .await
            .map_err(|e| anyhow::anyhow!("Failed to join Telegram bind save task: {e}"))??;
        Ok(())
    }

    fn add_allowed_identity_runtime(&self, identity: &str) {
        let normalized = Self::normalize_identity(identity);
        if normalized.is_empty() {
            return;
        }
        if let Ok(mut users) = self.allowed_users.write() {
            if !users.iter().any(|u| u == &normalized) {
                users.push(normalized);
            }
        }
    }

    fn extract_bind_code(text: &str) -> Option<&str> {
        let mut parts = text.split_whitespace();
        let command = parts.next()?;
        let base_command = command.split('@').next().unwrap_or(command);
        if base_command != TELEGRAM_BIND_COMMAND {
            return None;
        }
        parts.next().map(str::trim).filter(|code| !code.is_empty())
    }

    fn pairing_code_active(&self) -> bool {
        self.pairing
            .as_ref()
            .and_then(PairingGuard::pairing_code)
            .is_some()
    }

    fn api_url(&self, method: &str) -> String {
        format!("https://api.telegram.org/bot{}/{method}", self.bot_token)
    }

    fn is_user_allowed(&self, username: &str) -> bool {
        let identity = Self::normalize_identity(username);
        self.allowed_users
            .read()
            .map(|users| users.iter().any(|u| u == "*" || u == &identity))
            .unwrap_or(false)
    }

    fn is_any_user_allowed<'a, I>(&self, identities: I) -> bool
    where
        I: IntoIterator<Item = &'a str>,
    {
        identities.into_iter().any(|id| self.is_user_allowed(id))
    }

    async fn handle_unauthorized_message(&self, update: &serde_json::Value) {
        let Some(message) = update.get("message") else {
            return;
        };

        let Some(text) = message.get("text").and_then(serde_json::Value::as_str) else {
            return;
        };

        let username_opt = message
            .get("from")
            .and_then(|from| from.get("username"))
            .and_then(serde_json::Value::as_str);
        let username = username_opt.unwrap_or("unknown");
        let normalized_username = Self::normalize_identity(username);

        let user_id = message
            .get("from")
            .and_then(|from| from.get("id"))
            .and_then(serde_json::Value::as_i64);
        let user_id_str = user_id.map(|id| id.to_string());
        let normalized_user_id = user_id_str.as_deref().map(Self::normalize_identity);

        let chat_id = message
            .get("chat")
            .and_then(|chat| chat.get("id"))
            .and_then(serde_json::Value::as_i64)
            .map(|id| id.to_string());

        let Some(chat_id) = chat_id else {
            tracing::warn!("Telegram: missing chat_id in message, skipping");
            return;
        };

        let mut identities = vec![normalized_username.as_str()];
        if let Some(ref id) = normalized_user_id {
            identities.push(id.as_str());
        }

        if self.is_any_user_allowed(identities.iter().copied()) {
            return;
        }

        if let Some(code) = Self::extract_bind_code(text) {
            if let Some(pairing) = self.pairing.as_ref() {
                match pairing.try_pair(code) {
                    Ok(Some(_token)) => {
                        let bind_identity = normalized_user_id.clone().or_else(|| {
                            if normalized_username.is_empty() || normalized_username == "unknown" {
                                None
                            } else {
                                Some(normalized_username.clone())
                            }
                        });

                        if let Some(identity) = bind_identity {
                            self.add_allowed_identity_runtime(&identity);
                            match self.persist_allowed_identity(&identity).await {
                                Ok(()) => {
                                    let _ = self
                                        .send(&SendMessage::new(
                                            "✅ Telegram account bound successfully. You can talk to ZeroClaw now.",
                                            &chat_id,
                                        ))
                                        .await;
                                    tracing::info!(
                                        "Telegram: paired and allowlisted identity={identity}"
                                    );
                                }
                                Err(e) => {
                                    tracing::error!(
                                        "Telegram: failed to persist allowlist after bind: {e}"
                                    );
                                    let _ = self
                                        .send(&SendMessage::new(
                                            "⚠️ Bound for this runtime, but failed to persist config. Access may be lost after restart; check config file permissions.",
                                            &chat_id,
                                        ))
                                        .await;
                                }
                            }
                        } else {
                            let _ = self
                                .send(&SendMessage::new(
                                    "❌ Could not identify your Telegram account. Ensure your account has a username or stable user ID, then retry.",
                                    &chat_id,
                                ))
                                .await;
                        }
                    }
                    Ok(None) => {
                        let _ = self
                            .send(&SendMessage::new(
                                "❌ Invalid binding code. Ask operator for the latest code and retry.",
                                &chat_id,
                            ))
                            .await;
                    }
                    Err(lockout_secs) => {
                        let _ = self
                            .send(&SendMessage::new(
                                format!("⏳ Too many invalid attempts. Retry in {lockout_secs}s."),
                                &chat_id,
                            ))
                            .await;
                    }
                }
            } else {
                let _ = self
                    .send(&SendMessage::new(
                        "ℹ️ Telegram pairing is not active. Ask operator to update allowlist in config.toml.",
                        &chat_id,
                    ))
                    .await;
            }
            return;
        }

        tracing::warn!(
            "Telegram: ignoring message from unauthorized user: username={username}, user_id={}. \
Allowlist Telegram username (without '@') or numeric user ID.",
            user_id_str.as_deref().unwrap_or("unknown")
        );

        let suggested_identity = normalized_user_id
            .clone()
            .or_else(|| {
                if normalized_username.is_empty() || normalized_username == "unknown" {
                    None
                } else {
                    Some(normalized_username.clone())
                }
            })
            .unwrap_or_else(|| "YOUR_TELEGRAM_ID".to_string());

        let _ = self
            .send(&SendMessage::new(
                format!(
                    "🔐 This bot requires operator approval.\n\nCopy this command to operator terminal:\n`zeroclaw channel bind-telegram {suggested_identity}`\n\nAfter operator runs it, send your message again."
                ),
                &chat_id,
            ))
            .await;

        if self.pairing_code_active() {
            let _ = self
                .send(&SendMessage::new(
                    "ℹ️ If operator provides a one-time pairing code, you can also run `/bind <code>`.",
                    &chat_id,
                ))
                .await;
        }
    }

    fn parse_update_message(&self, update: &serde_json::Value) -> Option<ChannelMessage> {
        let message = update.get("message")?;

        let text = message.get("text").and_then(serde_json::Value::as_str)?;

        let username = message
            .get("from")
            .and_then(|from| from.get("username"))
            .and_then(serde_json::Value::as_str)
            .unwrap_or("unknown")
            .to_string();

        let user_id = message
            .get("from")
            .and_then(|from| from.get("id"))
            .and_then(serde_json::Value::as_i64)
            .map(|id| id.to_string());

        let sender_identity = if username == "unknown" {
            user_id.clone().unwrap_or_else(|| "unknown".to_string())
        } else {
            username.clone()
        };

        let mut identities = vec![username.as_str()];
        if let Some(id) = user_id.as_deref() {
            identities.push(id);
        }

        if !self.is_any_user_allowed(identities.iter().copied()) {
            return None;
        }

        let chat_id = message
            .get("chat")
            .and_then(|chat| chat.get("id"))
            .and_then(serde_json::Value::as_i64)
            .map(|id| id.to_string())?;

        let message_id = message
            .get("message_id")
            .and_then(serde_json::Value::as_i64)
            .unwrap_or(0);

        // Extract thread/topic ID for forum support
        let thread_id = message
            .get("message_thread_id")
            .and_then(serde_json::Value::as_i64)
            .map(|id| id.to_string());

        // reply_target: chat_id or chat_id:thread_id format
        let reply_target = if let Some(tid) = thread_id {
            format!("{}:{}", chat_id, tid)
        } else {
            chat_id.clone()
        };

        Some(ChannelMessage {
            id: format!("telegram_{chat_id}_{message_id}"),
            sender: sender_identity,
            reply_target,
            content: text.to_string(),
            channel: "telegram".to_string(),
            timestamp: std::time::SystemTime::now()
                .duration_since(std::time::UNIX_EPOCH)
                .unwrap_or_default()
                .as_secs(),
        })
    }

    async fn send_text_chunks(
        &self,
        message: &str,
        chat_id: &str,
        thread_id: Option<&str>,
    ) -> anyhow::Result<()> {
        let chunks = split_message_for_telegram(message);

        for (index, chunk) in chunks.iter().enumerate() {
            let text = if chunks.len() > 1 {
                if index == 0 {
                    format!("{chunk}\n\n(continues...)")
                } else if index == chunks.len() - 1 {
                    format!("(continued)\n\n{chunk}")
                } else {
                    format!("(continued)\n\n{chunk}\n\n(continues...)")
                }
            } else {
                chunk.to_string()
            };

            let mut markdown_body = serde_json::json!({
                "chat_id": chat_id,
                "text": text,
                "parse_mode": "Markdown"
            });

            // Add message_thread_id for forum topic support
            if let Some(tid) = thread_id {
                markdown_body["message_thread_id"] = serde_json::Value::String(tid.to_string());
            }

            let markdown_resp = self
                .client
                .post(self.api_url("sendMessage"))
                .json(&markdown_body)
                .send()
                .await?;

            if markdown_resp.status().is_success() {
                if index < chunks.len() - 1 {
                    tokio::time::sleep(Duration::from_millis(100)).await;
                }
                continue;
            }

            let markdown_status = markdown_resp.status();
            let markdown_err = markdown_resp.text().await.unwrap_or_default();
            tracing::warn!(
                status = ?markdown_status,
                "Telegram sendMessage with Markdown failed; retrying without parse_mode"
            );

            let mut plain_body = serde_json::json!({
                "chat_id": chat_id,
                "text": text,
            });

            // Add message_thread_id for forum topic support
            if let Some(tid) = thread_id {
                plain_body["message_thread_id"] = serde_json::Value::String(tid.to_string());
            }
            let plain_resp = self
                .client
                .post(self.api_url("sendMessage"))
                .json(&plain_body)
                .send()
                .await?;

            if !plain_resp.status().is_success() {
                let plain_status = plain_resp.status();
                let plain_err = plain_resp.text().await.unwrap_or_default();
                anyhow::bail!(
                    "Telegram sendMessage failed (markdown {}: {}; plain {}: {})",
                    markdown_status,
                    markdown_err,
                    plain_status,
                    plain_err
                );
            }

            if index < chunks.len() - 1 {
                tokio::time::sleep(Duration::from_millis(100)).await;
            }
        }

        Ok(())
    }

    async fn send_media_by_url(
        &self,
        method: &str,
        media_field: &str,
        chat_id: &str,
        thread_id: Option<&str>,
        url: &str,
        caption: Option<&str>,
    ) -> anyhow::Result<()> {
        let mut body = serde_json::json!({
            "chat_id": chat_id,
        });
        body[media_field] = serde_json::Value::String(url.to_string());

        if let Some(tid) = thread_id {
            body["message_thread_id"] = serde_json::Value::String(tid.to_string());
        }

        if let Some(cap) = caption {
            body["caption"] = serde_json::Value::String(cap.to_string());
        }

        let resp = self
            .client
            .post(self.api_url(method))
            .json(&body)
            .send()
            .await?;

        if !resp.status().is_success() {
            let err = resp.text().await?;
            anyhow::bail!("Telegram {method} by URL failed: {err}");
        }

        tracing::info!("Telegram {method} sent to {chat_id}: {url}");
        Ok(())
    }

    async fn send_attachment(
        &self,
        chat_id: &str,
        thread_id: Option<&str>,
        attachment: &TelegramAttachment,
    ) -> anyhow::Result<()> {
        let target = attachment.target.trim();

        if is_http_url(target) {
            return match attachment.kind {
                TelegramAttachmentKind::Image => {
                    self.send_photo_by_url(chat_id, thread_id, target, None)
                        .await
                }
                TelegramAttachmentKind::Document => {
                    self.send_document_by_url(chat_id, thread_id, target, None)
                        .await
                }
                TelegramAttachmentKind::Video => {
                    self.send_video_by_url(chat_id, thread_id, target, None)
                        .await
                }
                TelegramAttachmentKind::Audio => {
                    self.send_audio_by_url(chat_id, thread_id, target, None)
                        .await
                }
                TelegramAttachmentKind::Voice => {
                    self.send_voice_by_url(chat_id, thread_id, target, None)
                        .await
                }
            };
        }

        let path = Path::new(target);
        if !path.exists() {
            anyhow::bail!("Telegram attachment path not found: {target}");
        }

        match attachment.kind {
            TelegramAttachmentKind::Image => self.send_photo(chat_id, thread_id, path, None).await,
            TelegramAttachmentKind::Document => {
                self.send_document(chat_id, thread_id, path, None).await
            }
            TelegramAttachmentKind::Video => self.send_video(chat_id, thread_id, path, None).await,
            TelegramAttachmentKind::Audio => self.send_audio(chat_id, thread_id, path, None).await,
            TelegramAttachmentKind::Voice => self.send_voice(chat_id, thread_id, path, None).await,
        }
    }

    /// Send a document/file to a Telegram chat
    pub async fn send_document(
        &self,
        chat_id: &str,
        thread_id: Option<&str>,
        file_path: &Path,
        caption: Option<&str>,
    ) -> anyhow::Result<()> {
        let file_name = file_path
            .file_name()
            .and_then(|n| n.to_str())
            .unwrap_or("file");

        let file_bytes = tokio::fs::read(file_path).await?;
        let part = Part::bytes(file_bytes).file_name(file_name.to_string());

        let mut form = Form::new()
            .text("chat_id", chat_id.to_string())
            .part("document", part);

        if let Some(tid) = thread_id {
            form = form.text("message_thread_id", tid.to_string());
        }

        if let Some(cap) = caption {
            form = form.text("caption", cap.to_string());
        }

        let resp = self
            .client
            .post(self.api_url("sendDocument"))
            .multipart(form)
            .send()
            .await?;

        if !resp.status().is_success() {
            let err = resp.text().await?;
            anyhow::bail!("Telegram sendDocument failed: {err}");
        }

        tracing::info!("Telegram document sent to {chat_id}: {file_name}");
        Ok(())
    }

    /// Send a document from bytes (in-memory) to a Telegram chat
    pub async fn send_document_bytes(
        &self,
        chat_id: &str,
        thread_id: Option<&str>,
        file_bytes: Vec<u8>,
        file_name: &str,
        caption: Option<&str>,
    ) -> anyhow::Result<()> {
        let part = Part::bytes(file_bytes).file_name(file_name.to_string());

        let mut form = Form::new()
            .text("chat_id", chat_id.to_string())
            .part("document", part);

        if let Some(tid) = thread_id {
            form = form.text("message_thread_id", tid.to_string());
        }

        if let Some(cap) = caption {
            form = form.text("caption", cap.to_string());
        }

        let resp = self
            .client
            .post(self.api_url("sendDocument"))
            .multipart(form)
            .send()
            .await?;

        if !resp.status().is_success() {
            let err = resp.text().await?;
            anyhow::bail!("Telegram sendDocument failed: {err}");
        }

        tracing::info!("Telegram document sent to {chat_id}: {file_name}");
        Ok(())
    }

    /// Send a photo to a Telegram chat
    pub async fn send_photo(
        &self,
        chat_id: &str,
        thread_id: Option<&str>,
        file_path: &Path,
        caption: Option<&str>,
    ) -> anyhow::Result<()> {
        let file_name = file_path
            .file_name()
            .and_then(|n| n.to_str())
            .unwrap_or("photo.jpg");

        let file_bytes = tokio::fs::read(file_path).await?;
        let part = Part::bytes(file_bytes).file_name(file_name.to_string());

        let mut form = Form::new()
            .text("chat_id", chat_id.to_string())
            .part("photo", part);

        if let Some(tid) = thread_id {
            form = form.text("message_thread_id", tid.to_string());
        }

        if let Some(cap) = caption {
            form = form.text("caption", cap.to_string());
        }

        let resp = self
            .client
            .post(self.api_url("sendPhoto"))
            .multipart(form)
            .send()
            .await?;

        if !resp.status().is_success() {
            let err = resp.text().await?;
            anyhow::bail!("Telegram sendPhoto failed: {err}");
        }

        tracing::info!("Telegram photo sent to {chat_id}: {file_name}");
        Ok(())
    }

    /// Send a photo from bytes (in-memory) to a Telegram chat
    pub async fn send_photo_bytes(
        &self,
        chat_id: &str,
        thread_id: Option<&str>,
        file_bytes: Vec<u8>,
        file_name: &str,
        caption: Option<&str>,
    ) -> anyhow::Result<()> {
        let part = Part::bytes(file_bytes).file_name(file_name.to_string());

        let mut form = Form::new()
            .text("chat_id", chat_id.to_string())
            .part("photo", part);

        if let Some(tid) = thread_id {
            form = form.text("message_thread_id", tid.to_string());
        }

        if let Some(cap) = caption {
            form = form.text("caption", cap.to_string());
        }

        let resp = self
            .client
            .post(self.api_url("sendPhoto"))
            .multipart(form)
            .send()
            .await?;

        if !resp.status().is_success() {
            let err = resp.text().await?;
            anyhow::bail!("Telegram sendPhoto failed: {err}");
        }

        tracing::info!("Telegram photo sent to {chat_id}: {file_name}");
        Ok(())
    }

    /// Send a video to a Telegram chat
    pub async fn send_video(
        &self,
        chat_id: &str,
        thread_id: Option<&str>,
        file_path: &Path,
        caption: Option<&str>,
    ) -> anyhow::Result<()> {
        let file_name = file_path
            .file_name()
            .and_then(|n| n.to_str())
            .unwrap_or("video.mp4");

        let file_bytes = tokio::fs::read(file_path).await?;
        let part = Part::bytes(file_bytes).file_name(file_name.to_string());

        let mut form = Form::new()
            .text("chat_id", chat_id.to_string())
            .part("video", part);

        if let Some(tid) = thread_id {
            form = form.text("message_thread_id", tid.to_string());
        }

        if let Some(cap) = caption {
            form = form.text("caption", cap.to_string());
        }

        let resp = self
            .client
            .post(self.api_url("sendVideo"))
            .multipart(form)
            .send()
            .await?;

        if !resp.status().is_success() {
            let err = resp.text().await?;
            anyhow::bail!("Telegram sendVideo failed: {err}");
        }

        tracing::info!("Telegram video sent to {chat_id}: {file_name}");
        Ok(())
    }

    /// Send an audio file to a Telegram chat
    pub async fn send_audio(
        &self,
        chat_id: &str,
        thread_id: Option<&str>,
        file_path: &Path,
        caption: Option<&str>,
    ) -> anyhow::Result<()> {
        let file_name = file_path
            .file_name()
            .and_then(|n| n.to_str())
            .unwrap_or("audio.mp3");

        let file_bytes = tokio::fs::read(file_path).await?;
        let part = Part::bytes(file_bytes).file_name(file_name.to_string());

        let mut form = Form::new()
            .text("chat_id", chat_id.to_string())
            .part("audio", part);

        if let Some(tid) = thread_id {
            form = form.text("message_thread_id", tid.to_string());
        }

        if let Some(cap) = caption {
            form = form.text("caption", cap.to_string());
        }

        let resp = self
            .client
            .post(self.api_url("sendAudio"))
            .multipart(form)
            .send()
            .await?;

        if !resp.status().is_success() {
            let err = resp.text().await?;
            anyhow::bail!("Telegram sendAudio failed: {err}");
        }

        tracing::info!("Telegram audio sent to {chat_id}: {file_name}");
        Ok(())
    }

    /// Send a voice message to a Telegram chat
    pub async fn send_voice(
        &self,
        chat_id: &str,
        thread_id: Option<&str>,
        file_path: &Path,
        caption: Option<&str>,
    ) -> anyhow::Result<()> {
        let file_name = file_path
            .file_name()
            .and_then(|n| n.to_str())
            .unwrap_or("voice.ogg");

        let file_bytes = tokio::fs::read(file_path).await?;
        let part = Part::bytes(file_bytes).file_name(file_name.to_string());

        let mut form = Form::new()
            .text("chat_id", chat_id.to_string())
            .part("voice", part);

        if let Some(tid) = thread_id {
            form = form.text("message_thread_id", tid.to_string());
        }

        if let Some(cap) = caption {
            form = form.text("caption", cap.to_string());
        }

        let resp = self
            .client
            .post(self.api_url("sendVoice"))
            .multipart(form)
            .send()
            .await?;

        if !resp.status().is_success() {
            let err = resp.text().await?;
            anyhow::bail!("Telegram sendVoice failed: {err}");
        }

        tracing::info!("Telegram voice sent to {chat_id}: {file_name}");
        Ok(())
    }

    /// Send a file by URL (Telegram will download it)
    pub async fn send_document_by_url(
        &self,
        chat_id: &str,
        thread_id: Option<&str>,
        url: &str,
        caption: Option<&str>,
    ) -> anyhow::Result<()> {
        let mut body = serde_json::json!({
            "chat_id": chat_id,
            "document": url
        });

        if let Some(tid) = thread_id {
            body["message_thread_id"] = serde_json::Value::String(tid.to_string());
        }

        if let Some(cap) = caption {
            body["caption"] = serde_json::Value::String(cap.to_string());
        }

        let resp = self
            .client
            .post(self.api_url("sendDocument"))
            .json(&body)
            .send()
            .await?;

        if !resp.status().is_success() {
            let err = resp.text().await?;
            anyhow::bail!("Telegram sendDocument by URL failed: {err}");
        }

        tracing::info!("Telegram document (URL) sent to {chat_id}: {url}");
        Ok(())
    }

    /// Send a photo by URL (Telegram will download it)
    pub async fn send_photo_by_url(
        &self,
        chat_id: &str,
        thread_id: Option<&str>,
        url: &str,
        caption: Option<&str>,
    ) -> anyhow::Result<()> {
        let mut body = serde_json::json!({
            "chat_id": chat_id,
            "photo": url
        });

        if let Some(tid) = thread_id {
            body["message_thread_id"] = serde_json::Value::String(tid.to_string());
        }

        if let Some(cap) = caption {
            body["caption"] = serde_json::Value::String(cap.to_string());
        }

        let resp = self
            .client
            .post(self.api_url("sendPhoto"))
            .json(&body)
            .send()
            .await?;

        if !resp.status().is_success() {
            let err = resp.text().await?;
            anyhow::bail!("Telegram sendPhoto by URL failed: {err}");
        }

        tracing::info!("Telegram photo (URL) sent to {chat_id}: {url}");
        Ok(())
    }

    /// Send a video by URL (Telegram will download it)
    pub async fn send_video_by_url(
        &self,
        chat_id: &str,
        thread_id: Option<&str>,
        url: &str,
        caption: Option<&str>,
    ) -> anyhow::Result<()> {
        self.send_media_by_url("sendVideo", "video", chat_id, thread_id, url, caption)
            .await
    }

    /// Send an audio file by URL (Telegram will download it)
    pub async fn send_audio_by_url(
        &self,
        chat_id: &str,
        thread_id: Option<&str>,
        url: &str,
        caption: Option<&str>,
    ) -> anyhow::Result<()> {
        self.send_media_by_url("sendAudio", "audio", chat_id, thread_id, url, caption)
            .await
    }

    /// Send a voice message by URL (Telegram will download it)
    pub async fn send_voice_by_url(
        &self,
        chat_id: &str,
        thread_id: Option<&str>,
        url: &str,
        caption: Option<&str>,
    ) -> anyhow::Result<()> {
        self.send_media_by_url("sendVoice", "voice", chat_id, thread_id, url, caption)
            .await
    }
}

#[async_trait]
impl Channel for TelegramChannel {
    fn name(&self) -> &str {
        "telegram"
    }

    async fn send(&self, message: &SendMessage) -> anyhow::Result<()> {
        // Strip tool_call tags before processing to prevent Markdown parsing failures
        let content = strip_tool_call_tags(&message.content);

        // Parse recipient: "chat_id" or "chat_id:thread_id" format
        let (chat_id, thread_id) = match message.recipient.split_once(':') {
            Some((chat, thread)) => (chat, Some(thread)),
            None => (message.recipient.as_str(), None),
        };

        let (text_without_markers, attachments) = parse_attachment_markers(&content);

        if !attachments.is_empty() {
            if !text_without_markers.is_empty() {
                self.send_text_chunks(&text_without_markers, chat_id, thread_id)
                    .await?;
            }

            for attachment in &attachments {
                self.send_attachment(chat_id, thread_id, attachment).await?;
            }

            return Ok(());
        }

        if let Some(attachment) = parse_path_only_attachment(&content) {
            self.send_attachment(chat_id, thread_id, &attachment)
                .await?;
            return Ok(());
        }

        self.send_text_chunks(&content, chat_id, thread_id).await
    }

    async fn listen(&self, tx: tokio::sync::mpsc::Sender<ChannelMessage>) -> anyhow::Result<()> {
        let mut offset: i64 = 0;

        tracing::info!("Telegram channel listening for messages...");

        loop {
            let url = self.api_url("getUpdates");
            let body = serde_json::json!({
                "offset": offset,
                "timeout": 30,
                "allowed_updates": ["message"]
            });

            let resp = match self.client.post(&url).json(&body).send().await {
                Ok(r) => r,
                Err(e) => {
                    tracing::warn!("Telegram poll error: {e}");
                    tokio::time::sleep(std::time::Duration::from_secs(5)).await;
                    continue;
                }
            };

            let data: serde_json::Value = match resp.json().await {
                Ok(d) => d,
                Err(e) => {
                    tracing::warn!("Telegram parse error: {e}");
                    tokio::time::sleep(std::time::Duration::from_secs(5)).await;
                    continue;
                }
            };

            let ok = data
                .get("ok")
                .and_then(serde_json::Value::as_bool)
                .unwrap_or(true);
            if !ok {
                let error_code = data
                    .get("error_code")
                    .and_then(serde_json::Value::as_i64)
                    .unwrap_or_default();
                let description = data
                    .get("description")
                    .and_then(serde_json::Value::as_str)
                    .unwrap_or("unknown Telegram API error");

                if error_code == 409 {
                    tracing::warn!(
                        "Telegram polling conflict (409): {description}. \
Ensure only one `zeroclaw` process is using this bot token."
                    );
                    tokio::time::sleep(std::time::Duration::from_secs(2)).await;
                } else {
                    tracing::warn!(
                        "Telegram getUpdates API error (code={}): {description}",
                        error_code
                    );
                    tokio::time::sleep(std::time::Duration::from_secs(5)).await;
                }
                continue;
            }

            if let Some(results) = data.get("result").and_then(serde_json::Value::as_array) {
                for update in results {
                    // Advance offset past this update
                    if let Some(uid) = update.get("update_id").and_then(serde_json::Value::as_i64) {
                        offset = uid + 1;
                    }

                    let Some(msg) = self.parse_update_message(update) else {
                        self.handle_unauthorized_message(update).await;
                        continue;
                    };
                    // Send "typing" indicator immediately when we receive a message
                    let typing_body = serde_json::json!({
                        "chat_id": &msg.reply_target,
                        "action": "typing"
                    });
                    let _ = self
                        .client
                        .post(self.api_url("sendChatAction"))
                        .json(&typing_body)
                        .send()
                        .await; // Ignore errors for typing indicator

                    if tx.send(msg).await.is_err() {
                        return Ok(());
                    }
                }
            }
        }
    }

    async fn health_check(&self) -> bool {
        let timeout_duration = Duration::from_secs(5);

        match tokio::time::timeout(
            timeout_duration,
            self.client.get(self.api_url("getMe")).send(),
        )
        .await
        {
            Ok(Ok(resp)) => resp.status().is_success(),
            Ok(Err(e)) => {
                tracing::debug!("Telegram health check failed: {e}");
                false
            }
            Err(_) => {
                tracing::debug!("Telegram health check timed out after 5s");
                false
            }
        }
    }

    async fn start_typing(&self, recipient: &str) -> anyhow::Result<()> {
        self.stop_typing(recipient).await?;

        let client = self.client.clone();
        let url = self.api_url("sendChatAction");
        let chat_id = recipient.to_string();

        let handle = tokio::spawn(async move {
            loop {
                let body = serde_json::json!({
                    "chat_id": &chat_id,
                    "action": "typing"
                });
                let _ = client.post(&url).json(&body).send().await;
                // Telegram typing indicator expires after 5s; refresh at 4s
                tokio::time::sleep(Duration::from_secs(4)).await;
            }
        });

        let mut guard = self.typing_handle.lock();
        *guard = Some(handle);

        Ok(())
    }

    async fn stop_typing(&self, _recipient: &str) -> anyhow::Result<()> {
        let mut guard = self.typing_handle.lock();
        if let Some(handle) = guard.take() {
            handle.abort();
        }
        Ok(())
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn telegram_channel_name() {
        let ch = TelegramChannel::new("fake-token".into(), vec!["*".into()]);
        assert_eq!(ch.name(), "telegram");
    }

    #[test]
    fn typing_handle_starts_as_none() {
        let ch = TelegramChannel::new("fake-token".into(), vec!["*".into()]);
        let guard = ch.typing_handle.lock();
        assert!(guard.is_none());
    }

    #[tokio::test]
    async fn stop_typing_clears_handle() {
        let ch = TelegramChannel::new("fake-token".into(), vec!["*".into()]);

        // Manually insert a dummy handle
        {
            let mut guard = ch.typing_handle.lock();
            *guard = Some(tokio::spawn(async {
                tokio::time::sleep(Duration::from_secs(60)).await;
            }));
        }

        // stop_typing should abort and clear
        ch.stop_typing("123").await.unwrap();

        let guard = ch.typing_handle.lock();
        assert!(guard.is_none());
    }

    #[tokio::test]
    async fn start_typing_replaces_previous_handle() {
        let ch = TelegramChannel::new("fake-token".into(), vec!["*".into()]);

        // Insert a dummy handle first
        {
            let mut guard = ch.typing_handle.lock();
            *guard = Some(tokio::spawn(async {
                tokio::time::sleep(Duration::from_secs(60)).await;
            }));
        }

        // start_typing should abort the old handle and set a new one
        let _ = ch.start_typing("123").await;

        let guard = ch.typing_handle.lock();
        assert!(guard.is_some());
    }

    #[test]
    fn telegram_api_url() {
        let ch = TelegramChannel::new("123:ABC".into(), vec![]);
        assert_eq!(
            ch.api_url("getMe"),
            "https://api.telegram.org/bot123:ABC/getMe"
        );
    }

    #[test]
    fn telegram_user_allowed_wildcard() {
        let ch = TelegramChannel::new("t".into(), vec!["*".into()]);
        assert!(ch.is_user_allowed("anyone"));
    }

    #[test]
    fn telegram_user_allowed_specific() {
        let ch = TelegramChannel::new("t".into(), vec!["alice".into(), "bob".into()]);
        assert!(ch.is_user_allowed("alice"));
        assert!(!ch.is_user_allowed("eve"));
    }

    #[test]
    fn telegram_user_allowed_with_at_prefix_in_config() {
        let ch = TelegramChannel::new("t".into(), vec!["@alice".into()]);
        assert!(ch.is_user_allowed("alice"));
    }

    #[test]
    fn telegram_user_denied_empty() {
        let ch = TelegramChannel::new("t".into(), vec![]);
        assert!(!ch.is_user_allowed("anyone"));
    }

    #[test]
    fn telegram_user_exact_match_not_substring() {
        let ch = TelegramChannel::new("t".into(), vec!["alice".into()]);
        assert!(!ch.is_user_allowed("alice_bot"));
        assert!(!ch.is_user_allowed("alic"));
        assert!(!ch.is_user_allowed("malice"));
    }

    #[test]
    fn telegram_user_empty_string_denied() {
        let ch = TelegramChannel::new("t".into(), vec!["alice".into()]);
        assert!(!ch.is_user_allowed(""));
    }

    #[test]
    fn telegram_user_case_sensitive() {
        let ch = TelegramChannel::new("t".into(), vec!["Alice".into()]);
        assert!(ch.is_user_allowed("Alice"));
        assert!(!ch.is_user_allowed("alice"));
        assert!(!ch.is_user_allowed("ALICE"));
    }

    #[test]
    fn telegram_wildcard_with_specific_users() {
        let ch = TelegramChannel::new("t".into(), vec!["alice".into(), "*".into()]);
        assert!(ch.is_user_allowed("alice"));
        assert!(ch.is_user_allowed("bob"));
        assert!(ch.is_user_allowed("anyone"));
    }

    #[test]
    fn telegram_user_allowed_by_numeric_id_identity() {
        let ch = TelegramChannel::new("t".into(), vec!["123456789".into()]);
        assert!(ch.is_any_user_allowed(["unknown", "123456789"]));
    }

    #[test]
    fn telegram_user_denied_when_none_of_identities_match() {
        let ch = TelegramChannel::new("t".into(), vec!["alice".into(), "987654321".into()]);
        assert!(!ch.is_any_user_allowed(["unknown", "123456789"]));
    }

    #[test]
    fn telegram_pairing_enabled_with_empty_allowlist() {
        let ch = TelegramChannel::new("t".into(), vec![]);
        assert!(ch.pairing_code_active());
    }

    #[test]
    fn telegram_pairing_disabled_with_nonempty_allowlist() {
        let ch = TelegramChannel::new("t".into(), vec!["alice".into()]);
        assert!(!ch.pairing_code_active());
    }

    #[test]
    fn telegram_extract_bind_code_plain_command() {
        assert_eq!(
            TelegramChannel::extract_bind_code("/bind 123456"),
            Some("123456")
        );
    }

    #[test]
    fn telegram_extract_bind_code_supports_bot_mention() {
        assert_eq!(
            TelegramChannel::extract_bind_code("/bind@zeroclaw_bot 654321"),
            Some("654321")
        );
    }

    #[test]
    fn telegram_extract_bind_code_rejects_invalid_forms() {
        assert_eq!(TelegramChannel::extract_bind_code("/bind"), None);
        assert_eq!(TelegramChannel::extract_bind_code("/start"), None);
    }

    #[test]
    fn parse_attachment_markers_extracts_multiple_types() {
        let message = "Here are files [IMAGE:/tmp/a.png] and [DOCUMENT:https://example.com/a.pdf]";
        let (cleaned, attachments) = parse_attachment_markers(message);

        assert_eq!(cleaned, "Here are files  and");
        assert_eq!(attachments.len(), 2);
        assert_eq!(attachments[0].kind, TelegramAttachmentKind::Image);
        assert_eq!(attachments[0].target, "/tmp/a.png");
        assert_eq!(attachments[1].kind, TelegramAttachmentKind::Document);
        assert_eq!(attachments[1].target, "https://example.com/a.pdf");
    }

    #[test]
    fn parse_attachment_markers_keeps_invalid_markers_in_text() {
        let message = "Report [UNKNOWN:/tmp/a.bin]";
        let (cleaned, attachments) = parse_attachment_markers(message);

        assert_eq!(cleaned, "Report [UNKNOWN:/tmp/a.bin]");
        assert!(attachments.is_empty());
    }

    #[test]
    fn parse_path_only_attachment_detects_existing_file() {
        let dir = tempfile::tempdir().unwrap();
        let image_path = dir.path().join("snap.png");
        std::fs::write(&image_path, b"fake-png").unwrap();

        let parsed = parse_path_only_attachment(image_path.to_string_lossy().as_ref())
            .expect("expected attachment");

        assert_eq!(parsed.kind, TelegramAttachmentKind::Image);
        assert_eq!(parsed.target, image_path.to_string_lossy());
    }

    #[test]
    fn parse_path_only_attachment_rejects_sentence_text() {
        assert!(parse_path_only_attachment("Screenshot saved to /tmp/snap.png").is_none());
    }

    #[test]
    fn infer_attachment_kind_from_target_detects_document_extension() {
        assert_eq!(
            infer_attachment_kind_from_target("https://example.com/files/specs.pdf?download=1"),
            Some(TelegramAttachmentKind::Document)
        );
    }

    #[test]
    fn parse_update_message_uses_chat_id_as_reply_target() {
        let ch = TelegramChannel::new("token".into(), vec!["*".into()]);
        let update = serde_json::json!({
            "update_id": 1,
            "message": {
                "message_id": 33,
                "text": "hello",
                "from": {
                    "id": 555,
                    "username": "alice"
                },
                "chat": {
                    "id": -100_200_300
                }
            }
        });

        let msg = ch
            .parse_update_message(&update)
            .expect("message should parse");

        assert_eq!(msg.sender, "alice");
        assert_eq!(msg.reply_target, "-100200300");
        assert_eq!(msg.content, "hello");
        assert_eq!(msg.id, "telegram_-100200300_33");
    }

    #[test]
    fn parse_update_message_allows_numeric_id_without_username() {
        let ch = TelegramChannel::new("token".into(), vec!["555".into()]);
        let update = serde_json::json!({
            "update_id": 2,
            "message": {
                "message_id": 9,
                "text": "ping",
                "from": {
                    "id": 555
                },
                "chat": {
                    "id": 12345
                }
            }
        });

        let msg = ch
            .parse_update_message(&update)
            .expect("numeric allowlist should pass");

        assert_eq!(msg.sender, "555");
        assert_eq!(msg.reply_target, "12345");
    }

    #[test]
    fn parse_update_message_extracts_thread_id_for_forum_topic() {
        let ch = TelegramChannel::new("token".into(), vec!["*".into()]);
        let update = serde_json::json!({
            "update_id": 3,
            "message": {
                "message_id": 42,
                "text": "hello from topic",
                "from": {
                    "id": 555,
                    "username": "alice"
                },
                "chat": {
                    "id": -100_200_300
                },
                "message_thread_id": 789
            }
        });

        let msg = ch
            .parse_update_message(&update)
            .expect("message with thread_id should parse");

        assert_eq!(msg.sender, "alice");
        assert_eq!(msg.reply_target, "-100200300:789");
        assert_eq!(msg.content, "hello from topic");
        assert_eq!(msg.id, "telegram_-100200300_42");
    }

    // ── File sending API URL tests ──────────────────────────────────

    #[test]
    fn telegram_api_url_send_document() {
        let ch = TelegramChannel::new("123:ABC".into(), vec![]);
        assert_eq!(
            ch.api_url("sendDocument"),
            "https://api.telegram.org/bot123:ABC/sendDocument"
        );
    }

    #[test]
    fn telegram_api_url_send_photo() {
        let ch = TelegramChannel::new("123:ABC".into(), vec![]);
        assert_eq!(
            ch.api_url("sendPhoto"),
            "https://api.telegram.org/bot123:ABC/sendPhoto"
        );
    }

    #[test]
    fn telegram_api_url_send_video() {
        let ch = TelegramChannel::new("123:ABC".into(), vec![]);
        assert_eq!(
            ch.api_url("sendVideo"),
            "https://api.telegram.org/bot123:ABC/sendVideo"
        );
    }

    #[test]
    fn telegram_api_url_send_audio() {
        let ch = TelegramChannel::new("123:ABC".into(), vec![]);
        assert_eq!(
            ch.api_url("sendAudio"),
            "https://api.telegram.org/bot123:ABC/sendAudio"
        );
    }

    #[test]
    fn telegram_api_url_send_voice() {
        let ch = TelegramChannel::new("123:ABC".into(), vec![]);
        assert_eq!(
            ch.api_url("sendVoice"),
            "https://api.telegram.org/bot123:ABC/sendVoice"
        );
    }

    // ── File sending integration tests (with mock server) ──────────

    #[tokio::test]
    async fn telegram_send_document_bytes_builds_correct_form() {
        // This test verifies the method doesn't panic and handles bytes correctly
        let ch = TelegramChannel::new("fake-token".into(), vec!["*".into()]);
        let file_bytes = b"Hello, this is a test file content".to_vec();

        // The actual API call will fail (no real server), but we verify the method exists
        // and handles the input correctly up to the network call
        let result = ch
            .send_document_bytes("123456", None, file_bytes, "test.txt", Some("Test caption"))
            .await;

        // Should fail with network error, not a panic or type error
        assert!(result.is_err());
        let err = result.unwrap_err().to_string();
        // Error should be network-related, not a code bug
        assert!(
            err.contains("error") || err.contains("failed") || err.contains("connect"),
            "Expected network error, got: {err}"
        );
    }

    #[tokio::test]
    async fn telegram_send_photo_bytes_builds_correct_form() {
        let ch = TelegramChannel::new("fake-token".into(), vec!["*".into()]);
        // Minimal valid PNG header bytes
        let file_bytes = vec![0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A];

        let result = ch
            .send_photo_bytes("123456", None, file_bytes, "test.png", None)
            .await;

        assert!(result.is_err());
    }

    #[tokio::test]
    async fn telegram_send_document_by_url_builds_correct_json() {
        let ch = TelegramChannel::new("fake-token".into(), vec!["*".into()]);

        let result = ch
            .send_document_by_url(
                "123456",
                None,
                "https://example.com/file.pdf",
                Some("PDF doc"),
            )
            .await;

        assert!(result.is_err());
    }

    #[tokio::test]
    async fn telegram_send_photo_by_url_builds_correct_json() {
        let ch = TelegramChannel::new("fake-token".into(), vec!["*".into()]);

        let result = ch
            .send_photo_by_url("123456", None, "https://example.com/image.jpg", None)
            .await;

        assert!(result.is_err());
    }

    // ── File path handling tests ────────────────────────────────────

    #[tokio::test]
    async fn telegram_send_document_nonexistent_file() {
        let ch = TelegramChannel::new("fake-token".into(), vec!["*".into()]);
        let path = Path::new("/nonexistent/path/to/file.txt");

        let result = ch.send_document("123456", None, path, None).await;

        assert!(result.is_err());
        let err = result.unwrap_err().to_string();
        // Should fail with file not found error
        assert!(
            err.contains("No such file") || err.contains("not found") || err.contains("os error"),
            "Expected file not found error, got: {err}"
        );
    }

    #[tokio::test]
    async fn telegram_send_photo_nonexistent_file() {
        let ch = TelegramChannel::new("fake-token".into(), vec!["*".into()]);
        let path = Path::new("/nonexistent/path/to/photo.jpg");

        let result = ch.send_photo("123456", None, path, None).await;

        assert!(result.is_err());
    }

    #[tokio::test]
    async fn telegram_send_video_nonexistent_file() {
        let ch = TelegramChannel::new("fake-token".into(), vec!["*".into()]);
        let path = Path::new("/nonexistent/path/to/video.mp4");

        let result = ch.send_video("123456", None, path, None).await;

        assert!(result.is_err());
    }

    #[tokio::test]
    async fn telegram_send_audio_nonexistent_file() {
        let ch = TelegramChannel::new("fake-token".into(), vec!["*".into()]);
        let path = Path::new("/nonexistent/path/to/audio.mp3");

        let result = ch.send_audio("123456", None, path, None).await;

        assert!(result.is_err());
    }

    #[tokio::test]
    async fn telegram_send_voice_nonexistent_file() {
        let ch = TelegramChannel::new("fake-token".into(), vec!["*".into()]);
        let path = Path::new("/nonexistent/path/to/voice.ogg");

        let result = ch.send_voice("123456", None, path, None).await;

        assert!(result.is_err());
    }

    // ── Message splitting tests ─────────────────────────────────────

    #[test]
    fn telegram_split_short_message() {
        let msg = "Hello, world!";
        let chunks = split_message_for_telegram(msg);
        assert_eq!(chunks.len(), 1);
        assert_eq!(chunks[0], msg);
    }

    #[test]
    fn telegram_split_exact_limit() {
        let msg = "a".repeat(TELEGRAM_MAX_MESSAGE_LENGTH);
        let chunks = split_message_for_telegram(&msg);
        assert_eq!(chunks.len(), 1);
        assert_eq!(chunks[0].len(), TELEGRAM_MAX_MESSAGE_LENGTH);
    }

    #[test]
    fn telegram_split_over_limit() {
        let msg = "a".repeat(TELEGRAM_MAX_MESSAGE_LENGTH + 100);
        let chunks = split_message_for_telegram(&msg);
        assert_eq!(chunks.len(), 2);
        assert!(chunks[0].len() <= TELEGRAM_MAX_MESSAGE_LENGTH);
        assert!(chunks[1].len() <= TELEGRAM_MAX_MESSAGE_LENGTH);
    }

    #[test]
    fn telegram_split_at_word_boundary() {
        let msg = format!(
            "{} more text here",
            "word ".repeat(TELEGRAM_MAX_MESSAGE_LENGTH / 5)
        );
        let chunks = split_message_for_telegram(&msg);
        assert!(chunks.len() >= 2);
        // First chunk should end with a complete word (space at the end)
        for chunk in &chunks[..chunks.len() - 1] {
            assert!(chunk.len() <= TELEGRAM_MAX_MESSAGE_LENGTH);
        }
    }

    #[test]
    fn telegram_split_at_newline() {
        let text_block = "Line of text\n".repeat(TELEGRAM_MAX_MESSAGE_LENGTH / 13 + 1);
        let chunks = split_message_for_telegram(&text_block);
        assert!(chunks.len() >= 2);
        for chunk in chunks {
            assert!(chunk.len() <= TELEGRAM_MAX_MESSAGE_LENGTH);
        }
    }

    #[test]
    fn telegram_split_preserves_content() {
        let msg = "test ".repeat(TELEGRAM_MAX_MESSAGE_LENGTH / 5 + 100);
        let chunks = split_message_for_telegram(&msg);
        let rejoined = chunks.join("");
        assert_eq!(rejoined, msg);
    }

    #[test]
    fn telegram_split_empty_message() {
        let chunks = split_message_for_telegram("");
        assert_eq!(chunks.len(), 1);
        assert_eq!(chunks[0], "");
    }

    #[test]
    fn telegram_split_very_long_message() {
        let msg = "x".repeat(TELEGRAM_MAX_MESSAGE_LENGTH * 3);
        let chunks = split_message_for_telegram(&msg);
        assert!(chunks.len() >= 3);
        for chunk in chunks {
            assert!(chunk.len() <= TELEGRAM_MAX_MESSAGE_LENGTH);
        }
    }

    // ── Caption handling tests ──────────────────────────────────────

    #[tokio::test]
    async fn telegram_send_document_bytes_with_caption() {
        let ch = TelegramChannel::new("fake-token".into(), vec!["*".into()]);
        let file_bytes = b"test content".to_vec();

        // With caption
        let result = ch
            .send_document_bytes(
                "123456",
                None,
                file_bytes.clone(),
                "test.txt",
                Some("My caption"),
            )
            .await;
        assert!(result.is_err()); // Network error expected

        // Without caption
        let result = ch
            .send_document_bytes("123456", None, file_bytes, "test.txt", None)
            .await;
        assert!(result.is_err()); // Network error expected
    }

    #[tokio::test]
    async fn telegram_send_photo_bytes_with_caption() {
        let ch = TelegramChannel::new("fake-token".into(), vec!["*".into()]);
        let file_bytes = vec![0x89, 0x50, 0x4E, 0x47];

        // With caption
        let result = ch
            .send_photo_bytes(
                "123456",
                None,
                file_bytes.clone(),
                "test.png",
                Some("Photo caption"),
            )
            .await;
        assert!(result.is_err());

        // Without caption
        let result = ch
            .send_photo_bytes("123456", None, file_bytes, "test.png", None)
            .await;
        assert!(result.is_err());
    }

    // ── Empty/edge case tests ───────────────────────────────────────

    #[tokio::test]
    async fn telegram_send_document_bytes_empty_file() {
        let ch = TelegramChannel::new("fake-token".into(), vec!["*".into()]);
        let file_bytes: Vec<u8> = vec![];

        let result = ch
            .send_document_bytes("123456", None, file_bytes, "empty.txt", None)
            .await;

        // Should not panic, will fail at API level
        assert!(result.is_err());
    }

    #[tokio::test]
    async fn telegram_send_document_bytes_empty_filename() {
        let ch = TelegramChannel::new("fake-token".into(), vec!["*".into()]);
        let file_bytes = b"content".to_vec();

        let result = ch
            .send_document_bytes("123456", None, file_bytes, "", None)
            .await;

        // Should not panic
        assert!(result.is_err());
    }

    #[tokio::test]
    async fn telegram_send_document_bytes_empty_chat_id() {
        let ch = TelegramChannel::new("fake-token".into(), vec!["*".into()]);
        let file_bytes = b"content".to_vec();

        let result = ch
            .send_document_bytes("", None, file_bytes, "test.txt", None)
            .await;

        // Should not panic
        assert!(result.is_err());
    }

    // ── Message ID edge cases ─────────────────────────────────────

    #[test]
    fn telegram_message_id_format_includes_chat_and_message_id() {
        // Verify that message IDs follow the format: telegram_{chat_id}_{message_id}
        let chat_id = "123456";
        let message_id = 789;
        let expected_id = format!("telegram_{chat_id}_{message_id}");
        assert_eq!(expected_id, "telegram_123456_789");
    }

    #[test]
    fn telegram_message_id_is_deterministic() {
        // Same chat_id + same message_id = same ID (prevents duplicates after restart)
        let chat_id = "123456";
        let message_id = 789;
        let id1 = format!("telegram_{chat_id}_{message_id}");
        let id2 = format!("telegram_{chat_id}_{message_id}");
        assert_eq!(id1, id2);
    }

    #[test]
    fn telegram_message_id_different_message_different_id() {
        // Different message IDs produce different IDs
        let chat_id = "123456";
        let id1 = format!("telegram_{chat_id}_789");
        let id2 = format!("telegram_{chat_id}_790");
        assert_ne!(id1, id2);
    }

    #[test]
    fn telegram_message_id_different_chat_different_id() {
        // Different chats produce different IDs even with same message_id
        let message_id = 789;
        let id1 = format!("telegram_123456_{message_id}");
        let id2 = format!("telegram_789012_{message_id}");
        assert_ne!(id1, id2);
    }

    #[test]
    fn telegram_message_id_no_uuid_randomness() {
        // Verify format doesn't contain random UUID components
        let chat_id = "123456";
        let message_id = 789;
        let id = format!("telegram_{chat_id}_{message_id}");
        assert!(!id.contains('-')); // No UUID dashes
        assert!(id.starts_with("telegram_"));
    }

    #[test]
    fn telegram_message_id_handles_zero_message_id() {
        // Edge case: message_id can be 0 (fallback/missing case)
        let chat_id = "123456";
        let message_id = 0;
        let id = format!("telegram_{chat_id}_{message_id}");
        assert_eq!(id, "telegram_123456_0");
    }

    // ── Tool call tag stripping tests ───────────────────────────────────

    #[test]
    fn strip_tool_call_tags_removes_standard_tags() {
        let input =
            "Hello <tool>{\"name\":\"shell\",\"arguments\":{\"command\":\"ls\"}}</tool> world";
        let result = strip_tool_call_tags(input);
        assert_eq!(result, "Hello  world");
    }

    #[test]
    fn strip_tool_call_tags_removes_alias_tags() {
        let input = "Hello <toolcall>{\"name\":\"shell\",\"arguments\":{\"command\":\"ls\"}}</toolcall> world";
        let result = strip_tool_call_tags(input);
        assert_eq!(result, "Hello  world");
    }

    #[test]
    fn strip_tool_call_tags_removes_dash_tags() {
        let input = "Hello <tool-call>{\"name\":\"shell\",\"arguments\":{\"command\":\"ls\"}}</tool-call> world";
        let result = strip_tool_call_tags(input);
        assert_eq!(result, "Hello  world");
    }

    #[test]
    fn strip_tool_call_tags_handles_multiple_tags() {
        let input = "Start <tool>a</tool> middle <tool>b</tool> end";
        let result = strip_tool_call_tags(input);
        assert_eq!(result, "Start  middle  end");
    }

    #[test]
    fn strip_tool_call_tags_handles_mixed_tags() {
        let input = "A <tool>a</tool> B <toolcall>b</toolcall> C <tool-call>c</tool-call> D";
        let result = strip_tool_call_tags(input);
        assert_eq!(result, "A  B  C  D");
    }

    #[test]
    fn strip_tool_call_tags_preserves_normal_text() {
        let input = "Hello world! This is a test.";
        let result = strip_tool_call_tags(input);
        assert_eq!(result, "Hello world! This is a test.");
    }

    #[test]
    fn strip_tool_call_tags_handles_unclosed_tags() {
        let input = "Hello <tool>world";
        let result = strip_tool_call_tags(input);
        assert_eq!(result, "Hello <tool>world");
    }

    #[test]
    fn strip_tool_call_tags_cleans_extra_newlines() {
        let input = "Hello\n\n<tool>\ntest\n</tool>\n\n\nworld";
        let result = strip_tool_call_tags(input);
        assert_eq!(result, "Hello\n\nworld");
    }

    #[test]
    fn strip_tool_call_tags_handles_empty_input() {
        let input = "";
        let result = strip_tool_call_tags(input);
        assert_eq!(result, "");
    }

    #[test]
    fn strip_tool_call_tags_handles_only_tags() {
        let input = "<tool>{\"name\":\"test\"}</tool>";
        let result = strip_tool_call_tags(input);
        assert_eq!(result, "");
    }
}