use super::traits::{Channel, ChannelMessage, SendMessage};
use async_trait::async_trait;
use futures_util::{SinkExt, StreamExt};
use std::collections::HashMap;
use std::sync::Arc;
use tokio::sync::RwLock;
use tokio_tungstenite::tungstenite::Message;
use uuid::Uuid;

/// DingTalk channel — connects via Stream Mode WebSocket for real-time messages.
/// Replies are sent through per-message session webhook URLs.
pub struct DingTalkChannel {
    client_id: String,
    client_secret: String,
    allowed_users: Vec<String>,
    client: reqwest::Client,
    /// Per-chat session webhooks for sending replies (chatID -> webhook URL).
    /// DingTalk provides a unique webhook URL with each incoming message.
    session_webhooks: Arc<RwLock<HashMap<String, String>>>,
}

/// Response from DingTalk gateway connection registration.
#[derive(serde::Deserialize)]
struct GatewayResponse {
    endpoint: String,
    ticket: String,
}

impl DingTalkChannel {
    pub fn new(client_id: String, client_secret: String, allowed_users: Vec<String>) -> Self {
        Self {
            client_id,
            client_secret,
            allowed_users,
            client: reqwest::Client::new(),
            session_webhooks: Arc::new(RwLock::new(HashMap::new())),
        }
    }

    fn is_user_allowed(&self, user_id: &str) -> bool {
        self.allowed_users.iter().any(|u| u == "*" || u == user_id)
    }

    /// Register a connection with DingTalk's gateway to get a WebSocket endpoint.
    async fn register_connection(&self) -> anyhow::Result<GatewayResponse> {
        let body = serde_json::json!({
            "clientId": self.client_id,
            "clientSecret": self.client_secret,
        });

        let resp = self
            .client
            .post("https://api.dingtalk.com/v1.0/gateway/connections/open")
            .json(&body)
            .send()
            .await?;

        if !resp.status().is_success() {
            let status = resp.status();
            let err = resp.text().await.unwrap_or_default();
            anyhow::bail!("DingTalk gateway registration failed ({status}): {err}");
        }

        let gw: GatewayResponse = resp.json().await?;
        Ok(gw)
    }

    fn resolve_reply_target(
        sender_id: &str,
        conversation_type: &str,
        conversation_id: Option<&str>,
    ) -> String {
        if conversation_type == "1" {
            sender_id.to_string()
        } else {
            conversation_id.unwrap_or(sender_id).to_string()
        }
    }
}

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

    async fn send(&self, message: &SendMessage) -> anyhow::Result<()> {
        let webhooks = self.session_webhooks.read().await;
        let webhook_url = webhooks.get(&message.recipient).ok_or_else(|| {
            anyhow::anyhow!(
                "No session webhook found for chat {}. \
                 The user must send a message first to establish a session.",
                message.recipient
            )
        })?;

        let title = message.subject.as_deref().unwrap_or("ZeroClaw");
        let body = serde_json::json!({
            "msgtype": "markdown",
            "markdown": {
                "title": title,
                "text": message.content,
            }
        });

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

        if !resp.status().is_success() {
            let status = resp.status();
            let err = resp.text().await.unwrap_or_default();
            anyhow::bail!("DingTalk webhook reply failed ({status}): {err}");
        }

        Ok(())
    }

    async fn listen(&self, tx: tokio::sync::mpsc::Sender<ChannelMessage>) -> anyhow::Result<()> {
        tracing::info!("DingTalk: registering gateway connection...");

        let gw = self.register_connection().await?;
        let ws_url = format!("{}?ticket={}", gw.endpoint, gw.ticket);

        tracing::info!("DingTalk: connecting to stream WebSocket...");
        let (ws_stream, _) = tokio_tungstenite::connect_async(&ws_url).await?;
        let (mut write, mut read) = ws_stream.split();

        tracing::info!("DingTalk: connected and listening for messages...");

        while let Some(msg) = read.next().await {
            let msg = match msg {
                Ok(Message::Text(t)) => t,
                Ok(Message::Close(_)) => break,
                Err(e) => {
                    tracing::warn!("DingTalk WebSocket error: {e}");
                    break;
                }
                _ => continue,
            };

            let frame: serde_json::Value = match serde_json::from_str(&msg) {
                Ok(v) => v,
                Err(_) => continue,
            };

            let frame_type = frame.get("type").and_then(|t| t.as_str()).unwrap_or("");

            match frame_type {
                "SYSTEM" => {
                    // Respond to system pings to keep the connection alive
                    let message_id = frame
                        .get("headers")
                        .and_then(|h| h.get("messageId"))
                        .and_then(|m| m.as_str())
                        .unwrap_or("");

                    let pong = serde_json::json!({
                        "code": 200,
                        "headers": {
                            "contentType": "application/json",
                            "messageId": message_id,
                        },
                        "message": "OK",
                        "data": "",
                    });

                    if let Err(e) = write.send(Message::Text(pong.to_string())).await {
                        tracing::warn!("DingTalk: failed to send pong: {e}");
                        break;
                    }
                }
                "EVENT" => {
                    // Parse the chatbot callback data from the event
                    let data_str = frame.get("data").and_then(|d| d.as_str()).unwrap_or("{}");

                    let data: serde_json::Value = match serde_json::from_str(data_str) {
                        Ok(v) => v,
                        Err(_) => continue,
                    };

                    // Extract message content
                    let content = data
                        .get("text")
                        .and_then(|t| t.get("content"))
                        .and_then(|c| c.as_str())
                        .unwrap_or("")
                        .trim();

                    if content.is_empty() {
                        continue;
                    }

                    let sender_id = data
                        .get("senderStaffId")
                        .and_then(|s| s.as_str())
                        .unwrap_or("unknown");

                    if !self.is_user_allowed(sender_id) {
                        tracing::warn!(
                            "DingTalk: ignoring message from unauthorized user: {sender_id}"
                        );
                        continue;
                    }

                    let conversation_type = data
                        .get("conversationType")
                        .and_then(|c| c.as_str())
                        .unwrap_or("1");

                    // Private chat uses sender ID, group chat uses conversation ID
                    let chat_id = Self::resolve_reply_target(
                        sender_id,
                        conversation_type,
                        data.get("conversationId").and_then(|c| c.as_str()),
                    );

                    // Store session webhook for later replies
                    if let Some(webhook) = data.get("sessionWebhook").and_then(|w| w.as_str()) {
                        let mut webhooks = self.session_webhooks.write().await;
                        webhooks.insert(chat_id.clone(), webhook.to_string());
                    }

                    // Acknowledge the event
                    let message_id = frame
                        .get("headers")
                        .and_then(|h| h.get("messageId"))
                        .and_then(|m| m.as_str())
                        .unwrap_or("");

                    let ack = serde_json::json!({
                        "code": 200,
                        "headers": {
                            "contentType": "application/json",
                            "messageId": message_id,
                        },
                        "message": "OK",
                        "data": "",
                    });
                    let _ = write.send(Message::Text(ack.to_string())).await;

                    let channel_msg = ChannelMessage {
                        id: Uuid::new_v4().to_string(),
                        sender: sender_id.to_string(),
                        reply_target: chat_id,
                        content: content.to_string(),
                        channel: "dingtalk".to_string(),
                        timestamp: std::time::SystemTime::now()
                            .duration_since(std::time::UNIX_EPOCH)
                            .unwrap_or_default()
                            .as_secs(),
                    };

                    if tx.send(channel_msg).await.is_err() {
                        tracing::warn!("DingTalk: message channel closed");
                        break;
                    }
                }
                _ => {}
            }
        }

        anyhow::bail!("DingTalk WebSocket stream ended")
    }

    async fn health_check(&self) -> bool {
        self.register_connection().await.is_ok()
    }
}

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

    #[test]
    fn test_name() {
        let ch = DingTalkChannel::new("id".into(), "secret".into(), vec![]);
        assert_eq!(ch.name(), "dingtalk");
    }

    #[test]
    fn test_user_allowed_wildcard() {
        let ch = DingTalkChannel::new("id".into(), "secret".into(), vec!["*".into()]);
        assert!(ch.is_user_allowed("anyone"));
    }

    #[test]
    fn test_user_allowed_specific() {
        let ch = DingTalkChannel::new("id".into(), "secret".into(), vec!["user123".into()]);
        assert!(ch.is_user_allowed("user123"));
        assert!(!ch.is_user_allowed("other"));
    }

    #[test]
    fn test_user_denied_empty() {
        let ch = DingTalkChannel::new("id".into(), "secret".into(), vec![]);
        assert!(!ch.is_user_allowed("anyone"));
    }

    #[test]
    fn test_config_serde() {
        let toml_str = r#"
client_id = "app_id_123"
client_secret = "secret_456"
allowed_users = ["user1", "*"]
"#;
        let config: crate::config::schema::DingTalkConfig = toml::from_str(toml_str).unwrap();
        assert_eq!(config.client_id, "app_id_123");
        assert_eq!(config.client_secret, "secret_456");
        assert_eq!(config.allowed_users, vec!["user1", "*"]);
    }

    #[test]
    fn test_config_serde_defaults() {
        let toml_str = r#"
client_id = "id"
client_secret = "secret"
"#;
        let config: crate::config::schema::DingTalkConfig = toml::from_str(toml_str).unwrap();
        assert!(config.allowed_users.is_empty());
    }

    #[test]
    fn test_resolve_reply_target_private_chat_uses_sender_id() {
        let target = DingTalkChannel::resolve_reply_target("staff_1", "1", Some("conv_1"));
        assert_eq!(target, "staff_1");
    }

    #[test]
    fn test_resolve_reply_target_group_chat_uses_conversation_id() {
        let target = DingTalkChannel::resolve_reply_target("staff_1", "2", Some("conv_1"));
        assert_eq!(target, "conv_1");
    }

    #[test]
    fn test_resolve_reply_target_group_chat_falls_back_to_sender_id() {
        let target = DingTalkChannel::resolve_reply_target("staff_1", "2", None);
        assert_eq!(target, "staff_1");
    }
}