use super::traits::{Channel, ChannelMessage};
use async_trait::async_trait;
use uuid::Uuid;

/// WhatsApp channel — uses WhatsApp Business Cloud API
///
/// This channel operates in webhook mode (push-based) rather than polling.
/// Messages are received via the gateway's `/whatsapp` webhook endpoint.
/// The `listen` method here is a no-op placeholder; actual message handling
/// happens in the gateway when Meta sends webhook events.
pub struct WhatsAppChannel {
    access_token: String,
    phone_number_id: String,
    verify_token: String,
    allowed_numbers: Vec<String>,
    client: reqwest::Client,
}

impl WhatsAppChannel {
    pub fn new(
        access_token: String,
        phone_number_id: String,
        verify_token: String,
        allowed_numbers: Vec<String>,
    ) -> Self {
        Self {
            access_token,
            phone_number_id,
            verify_token,
            allowed_numbers,
            client: reqwest::Client::new(),
        }
    }

    /// Check if a phone number is allowed (E.164 format: +1234567890)
    fn is_number_allowed(&self, phone: &str) -> bool {
        self.allowed_numbers
            .iter()
            .any(|n| n == "*" || n == phone)
    }

    /// Get the verify token for webhook verification
    pub fn verify_token(&self) -> &str {
        &self.verify_token
    }

    /// Parse an incoming webhook payload from Meta and extract messages
    pub fn parse_webhook_payload(
        &self,
        payload: &serde_json::Value,
    ) -> Vec<ChannelMessage> {
        let mut messages = Vec::new();

        // WhatsApp Cloud API webhook structure:
        // { "object": "whatsapp_business_account", "entry": [...] }
        let Some(entries) = payload.get("entry").and_then(|e| e.as_array()) else {
            return messages;
        };

        for entry in entries {
            let Some(changes) = entry.get("changes").and_then(|c| c.as_array()) else {
                continue;
            };

            for change in changes {
                let Some(value) = change.get("value") else {
                    continue;
                };

                // Extract messages array
                let Some(msgs) = value.get("messages").and_then(|m| m.as_array()) else {
                    continue;
                };

                for msg in msgs {
                    // Get sender phone number
                    let Some(from) = msg.get("from").and_then(|f| f.as_str()) else {
                        continue;
                    };

                    // Check allowlist
                    let normalized_from = if from.starts_with('+') {
                        from.to_string()
                    } else {
                        format!("+{from}")
                    };

                    if !self.is_number_allowed(&normalized_from) {
                        tracing::warn!(
                            "WhatsApp: ignoring message from unauthorized number: {normalized_from}. \
                            Add to allowed_numbers in config.toml, then run `zeroclaw onboard --channels-only`."
                        );
                        continue;
                    }

                    // Extract text content (support text messages only for now)
                    let content = if let Some(text_obj) = msg.get("text") {
                        text_obj
                            .get("body")
                            .and_then(|b| b.as_str())
                            .unwrap_or("")
                            .to_string()
                    } else {
                        // Could be image, audio, etc. — skip for now
                        tracing::debug!("WhatsApp: skipping non-text message from {from}");
                        continue;
                    };

                    if content.is_empty() {
                        continue;
                    }

                    // Get timestamp
                    let timestamp = msg
                        .get("timestamp")
                        .and_then(|t| t.as_str())
                        .and_then(|t| t.parse::<u64>().ok())
                        .unwrap_or_else(|| {
                            std::time::SystemTime::now()
                                .duration_since(std::time::UNIX_EPOCH)
                                .unwrap_or_default()
                                .as_secs()
                        });

                    messages.push(ChannelMessage {
                        id: Uuid::new_v4().to_string(),
                        sender: normalized_from,
                        content,
                        channel: "whatsapp".to_string(),
                        timestamp,
                    });
                }
            }
        }

        messages
    }
}

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

    async fn send(&self, message: &str, recipient: &str) -> anyhow::Result<()> {
        // WhatsApp Cloud API: POST to /v18.0/{phone_number_id}/messages
        let url = format!(
            "https://graph.facebook.com/v18.0/{}/messages",
            self.phone_number_id
        );

        // Normalize recipient (remove leading + if present for API)
        let to = recipient.strip_prefix('+').unwrap_or(recipient);

        let body = serde_json::json!({
            "messaging_product": "whatsapp",
            "recipient_type": "individual",
            "to": to,
            "type": "text",
            "text": {
                "preview_url": false,
                "body": message
            }
        });

        let resp = self
            .client
            .post(&url)
            .header("Authorization", format!("Bearer {}", self.access_token))
            .header("Content-Type", "application/json")
            .json(&body)
            .send()
            .await?;

        if !resp.status().is_success() {
            let status = resp.status();
            let error_body = resp.text().await.unwrap_or_default();
            tracing::error!("WhatsApp send failed: {status} — {error_body}");
            anyhow::bail!("WhatsApp API error: {status}");
        }

        Ok(())
    }

    async fn listen(&self, _tx: tokio::sync::mpsc::Sender<ChannelMessage>) -> anyhow::Result<()> {
        // WhatsApp uses webhooks (push-based), not polling.
        // Messages are received via the gateway's /whatsapp endpoint.
        // This method keeps the channel "alive" but doesn't actively poll.
        tracing::info!(
            "WhatsApp channel active (webhook mode). \
            Configure Meta webhook to POST to your gateway's /whatsapp endpoint."
        );

        // Keep the task alive — it will be cancelled when the channel shuts down
        loop {
            tokio::time::sleep(std::time::Duration::from_secs(3600)).await;
        }
    }

    async fn health_check(&self) -> bool {
        // Check if we can reach the WhatsApp API
        let url = format!(
            "https://graph.facebook.com/v18.0/{}",
            self.phone_number_id
        );

        self.client
            .get(&url)
            .header("Authorization", format!("Bearer {}", self.access_token))
            .send()
            .await
            .map(|r| r.status().is_success())
            .unwrap_or(false)
    }
}

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

    fn make_channel() -> WhatsAppChannel {
        WhatsAppChannel::new(
            "test-token".into(),
            "123456789".into(),
            "verify-me".into(),
            vec!["+1234567890".into()],
        )
    }

    #[test]
    fn whatsapp_channel_name() {
        let ch = make_channel();
        assert_eq!(ch.name(), "whatsapp");
    }

    #[test]
    fn whatsapp_verify_token() {
        let ch = make_channel();
        assert_eq!(ch.verify_token(), "verify-me");
    }

    #[test]
    fn whatsapp_number_allowed_exact() {
        let ch = make_channel();
        assert!(ch.is_number_allowed("+1234567890"));
        assert!(!ch.is_number_allowed("+9876543210"));
    }

    #[test]
    fn whatsapp_number_allowed_wildcard() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["*".into()],
        );
        assert!(ch.is_number_allowed("+1234567890"));
        assert!(ch.is_number_allowed("+9999999999"));
    }

    #[test]
    fn whatsapp_number_denied_empty() {
        let ch = WhatsAppChannel::new("tok".into(), "123".into(), "ver".into(), vec![]);
        assert!(!ch.is_number_allowed("+1234567890"));
    }

    #[test]
    fn whatsapp_parse_empty_payload() {
        let ch = make_channel();
        let payload = serde_json::json!({});
        let msgs = ch.parse_webhook_payload(&payload);
        assert!(msgs.is_empty());
    }

    #[test]
    fn whatsapp_parse_valid_text_message() {
        let ch = make_channel();
        let payload = serde_json::json!({
            "object": "whatsapp_business_account",
            "entry": [{
                "id": "123",
                "changes": [{
                    "value": {
                        "messaging_product": "whatsapp",
                        "metadata": {
                            "display_phone_number": "15551234567",
                            "phone_number_id": "123456789"
                        },
                        "messages": [{
                            "from": "1234567890",
                            "id": "wamid.xxx",
                            "timestamp": "1699999999",
                            "type": "text",
                            "text": {
                                "body": "Hello ZeroClaw!"
                            }
                        }]
                    },
                    "field": "messages"
                }]
            }]
        });

        let msgs = ch.parse_webhook_payload(&payload);
        assert_eq!(msgs.len(), 1);
        assert_eq!(msgs[0].sender, "+1234567890");
        assert_eq!(msgs[0].content, "Hello ZeroClaw!");
        assert_eq!(msgs[0].channel, "whatsapp");
        assert_eq!(msgs[0].timestamp, 1699999999);
    }

    #[test]
    fn whatsapp_parse_unauthorized_number() {
        let ch = make_channel();
        let payload = serde_json::json!({
            "object": "whatsapp_business_account",
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": [{
                            "from": "9999999999",
                            "timestamp": "1699999999",
                            "type": "text",
                            "text": { "body": "Spam" }
                        }]
                    }
                }]
            }]
        });

        let msgs = ch.parse_webhook_payload(&payload);
        assert!(msgs.is_empty(), "Unauthorized numbers should be filtered");
    }

    #[test]
    fn whatsapp_parse_non_text_message_skipped() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["*".into()],
        );
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": [{
                            "from": "1234567890",
                            "timestamp": "1699999999",
                            "type": "image",
                            "image": { "id": "img123" }
                        }]
                    }
                }]
            }]
        });

        let msgs = ch.parse_webhook_payload(&payload);
        assert!(msgs.is_empty(), "Non-text messages should be skipped");
    }

    #[test]
    fn whatsapp_parse_multiple_messages() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["*".into()],
        );
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": [
                            { "from": "111", "timestamp": "1", "type": "text", "text": { "body": "First" } },
                            { "from": "222", "timestamp": "2", "type": "text", "text": { "body": "Second" } }
                        ]
                    }
                }]
            }]
        });

        let msgs = ch.parse_webhook_payload(&payload);
        assert_eq!(msgs.len(), 2);
        assert_eq!(msgs[0].content, "First");
        assert_eq!(msgs[1].content, "Second");
    }

    #[test]
    fn whatsapp_parse_normalizes_phone_with_plus() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["+1234567890".into()],
        );
        // API sends without +, but we normalize to +
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": [{
                            "from": "1234567890",
                            "timestamp": "1",
                            "type": "text",
                            "text": { "body": "Hi" }
                        }]
                    }
                }]
            }]
        });

        let msgs = ch.parse_webhook_payload(&payload);
        assert_eq!(msgs.len(), 1);
        assert_eq!(msgs[0].sender, "+1234567890");
    }

    #[test]
    fn whatsapp_empty_text_skipped() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["*".into()],
        );
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": [{
                            "from": "111",
                            "timestamp": "1",
                            "type": "text",
                            "text": { "body": "" }
                        }]
                    }
                }]
            }]
        });

        let msgs = ch.parse_webhook_payload(&payload);
        assert!(msgs.is_empty());
    }

    // ══════════════════════════════════════════════════════════
    // EDGE CASES — Comprehensive coverage
    // ══════════════════════════════════════════════════════════

    #[test]
    fn whatsapp_parse_missing_entry_array() {
        let ch = make_channel();
        let payload = serde_json::json!({
            "object": "whatsapp_business_account"
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert!(msgs.is_empty());
    }

    #[test]
    fn whatsapp_parse_entry_not_array() {
        let ch = make_channel();
        let payload = serde_json::json!({
            "entry": "not_an_array"
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert!(msgs.is_empty());
    }

    #[test]
    fn whatsapp_parse_missing_changes_array() {
        let ch = make_channel();
        let payload = serde_json::json!({
            "entry": [{ "id": "123" }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert!(msgs.is_empty());
    }

    #[test]
    fn whatsapp_parse_changes_not_array() {
        let ch = make_channel();
        let payload = serde_json::json!({
            "entry": [{
                "changes": "not_an_array"
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert!(msgs.is_empty());
    }

    #[test]
    fn whatsapp_parse_missing_value() {
        let ch = make_channel();
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{ "field": "messages" }]
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert!(msgs.is_empty());
    }

    #[test]
    fn whatsapp_parse_missing_messages_array() {
        let ch = make_channel();
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "metadata": {}
                    }
                }]
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert!(msgs.is_empty());
    }

    #[test]
    fn whatsapp_parse_messages_not_array() {
        let ch = make_channel();
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": "not_an_array"
                    }
                }]
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert!(msgs.is_empty());
    }

    #[test]
    fn whatsapp_parse_missing_from_field() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["*".into()],
        );
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": [{
                            "timestamp": "1",
                            "type": "text",
                            "text": { "body": "No sender" }
                        }]
                    }
                }]
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert!(msgs.is_empty(), "Messages without 'from' should be skipped");
    }

    #[test]
    fn whatsapp_parse_missing_text_body() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["*".into()],
        );
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": [{
                            "from": "111",
                            "timestamp": "1",
                            "type": "text",
                            "text": {}
                        }]
                    }
                }]
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert!(msgs.is_empty(), "Messages with empty text object should be skipped");
    }

    #[test]
    fn whatsapp_parse_null_text_body() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["*".into()],
        );
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": [{
                            "from": "111",
                            "timestamp": "1",
                            "type": "text",
                            "text": { "body": null }
                        }]
                    }
                }]
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert!(msgs.is_empty(), "Messages with null body should be skipped");
    }

    #[test]
    fn whatsapp_parse_invalid_timestamp_uses_current() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["*".into()],
        );
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": [{
                            "from": "111",
                            "timestamp": "not_a_number",
                            "type": "text",
                            "text": { "body": "Hello" }
                        }]
                    }
                }]
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert_eq!(msgs.len(), 1);
        // Timestamp should be current time (non-zero)
        assert!(msgs[0].timestamp > 0);
    }

    #[test]
    fn whatsapp_parse_missing_timestamp_uses_current() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["*".into()],
        );
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": [{
                            "from": "111",
                            "type": "text",
                            "text": { "body": "Hello" }
                        }]
                    }
                }]
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert_eq!(msgs.len(), 1);
        assert!(msgs[0].timestamp > 0);
    }

    #[test]
    fn whatsapp_parse_multiple_entries() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["*".into()],
        );
        let payload = serde_json::json!({
            "entry": [
                {
                    "changes": [{
                        "value": {
                            "messages": [{
                                "from": "111",
                                "timestamp": "1",
                                "type": "text",
                                "text": { "body": "Entry 1" }
                            }]
                        }
                    }]
                },
                {
                    "changes": [{
                        "value": {
                            "messages": [{
                                "from": "222",
                                "timestamp": "2",
                                "type": "text",
                                "text": { "body": "Entry 2" }
                            }]
                        }
                    }]
                }
            ]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert_eq!(msgs.len(), 2);
        assert_eq!(msgs[0].content, "Entry 1");
        assert_eq!(msgs[1].content, "Entry 2");
    }

    #[test]
    fn whatsapp_parse_multiple_changes() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["*".into()],
        );
        let payload = serde_json::json!({
            "entry": [{
                "changes": [
                    {
                        "value": {
                            "messages": [{
                                "from": "111",
                                "timestamp": "1",
                                "type": "text",
                                "text": { "body": "Change 1" }
                            }]
                        }
                    },
                    {
                        "value": {
                            "messages": [{
                                "from": "222",
                                "timestamp": "2",
                                "type": "text",
                                "text": { "body": "Change 2" }
                            }]
                        }
                    }
                ]
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert_eq!(msgs.len(), 2);
        assert_eq!(msgs[0].content, "Change 1");
        assert_eq!(msgs[1].content, "Change 2");
    }

    #[test]
    fn whatsapp_parse_status_update_ignored() {
        // Status updates have "statuses" instead of "messages"
        let ch = make_channel();
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "statuses": [{
                            "id": "wamid.xxx",
                            "status": "delivered",
                            "timestamp": "1699999999"
                        }]
                    }
                }]
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert!(msgs.is_empty(), "Status updates should be ignored");
    }

    #[test]
    fn whatsapp_parse_audio_message_skipped() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["*".into()],
        );
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": [{
                            "from": "111",
                            "timestamp": "1",
                            "type": "audio",
                            "audio": { "id": "audio123", "mime_type": "audio/ogg" }
                        }]
                    }
                }]
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert!(msgs.is_empty());
    }

    #[test]
    fn whatsapp_parse_video_message_skipped() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["*".into()],
        );
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": [{
                            "from": "111",
                            "timestamp": "1",
                            "type": "video",
                            "video": { "id": "video123" }
                        }]
                    }
                }]
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert!(msgs.is_empty());
    }

    #[test]
    fn whatsapp_parse_document_message_skipped() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["*".into()],
        );
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": [{
                            "from": "111",
                            "timestamp": "1",
                            "type": "document",
                            "document": { "id": "doc123", "filename": "file.pdf" }
                        }]
                    }
                }]
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert!(msgs.is_empty());
    }

    #[test]
    fn whatsapp_parse_sticker_message_skipped() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["*".into()],
        );
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": [{
                            "from": "111",
                            "timestamp": "1",
                            "type": "sticker",
                            "sticker": { "id": "sticker123" }
                        }]
                    }
                }]
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert!(msgs.is_empty());
    }

    #[test]
    fn whatsapp_parse_location_message_skipped() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["*".into()],
        );
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": [{
                            "from": "111",
                            "timestamp": "1",
                            "type": "location",
                            "location": { "latitude": 40.7128, "longitude": -74.0060 }
                        }]
                    }
                }]
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert!(msgs.is_empty());
    }

    #[test]
    fn whatsapp_parse_contacts_message_skipped() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["*".into()],
        );
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": [{
                            "from": "111",
                            "timestamp": "1",
                            "type": "contacts",
                            "contacts": [{ "name": { "formatted_name": "John" } }]
                        }]
                    }
                }]
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert!(msgs.is_empty());
    }

    #[test]
    fn whatsapp_parse_reaction_message_skipped() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["*".into()],
        );
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": [{
                            "from": "111",
                            "timestamp": "1",
                            "type": "reaction",
                            "reaction": { "message_id": "wamid.xxx", "emoji": "👍" }
                        }]
                    }
                }]
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert!(msgs.is_empty());
    }

    #[test]
    fn whatsapp_parse_mixed_authorized_unauthorized() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["+1111111111".into()],
        );
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": [
                            { "from": "1111111111", "timestamp": "1", "type": "text", "text": { "body": "Allowed" } },
                            { "from": "9999999999", "timestamp": "2", "type": "text", "text": { "body": "Blocked" } },
                            { "from": "1111111111", "timestamp": "3", "type": "text", "text": { "body": "Also allowed" } }
                        ]
                    }
                }]
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert_eq!(msgs.len(), 2);
        assert_eq!(msgs[0].content, "Allowed");
        assert_eq!(msgs[1].content, "Also allowed");
    }

    #[test]
    fn whatsapp_parse_unicode_message() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["*".into()],
        );
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": [{
                            "from": "111",
                            "timestamp": "1",
                            "type": "text",
                            "text": { "body": "Hello 👋 世界 🌍 مرحبا" }
                        }]
                    }
                }]
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert_eq!(msgs.len(), 1);
        assert_eq!(msgs[0].content, "Hello 👋 世界 🌍 مرحبا");
    }

    #[test]
    fn whatsapp_parse_very_long_message() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["*".into()],
        );
        let long_text = "A".repeat(10_000);
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": [{
                            "from": "111",
                            "timestamp": "1",
                            "type": "text",
                            "text": { "body": long_text }
                        }]
                    }
                }]
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert_eq!(msgs.len(), 1);
        assert_eq!(msgs[0].content.len(), 10_000);
    }

    #[test]
    fn whatsapp_parse_whitespace_only_message_skipped() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["*".into()],
        );
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": [{
                            "from": "111",
                            "timestamp": "1",
                            "type": "text",
                            "text": { "body": "   " }
                        }]
                    }
                }]
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        // Whitespace-only is NOT empty, so it passes through
        assert_eq!(msgs.len(), 1);
        assert_eq!(msgs[0].content, "   ");
    }

    #[test]
    fn whatsapp_number_allowed_multiple_numbers() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["+1111111111".into(), "+2222222222".into(), "+3333333333".into()],
        );
        assert!(ch.is_number_allowed("+1111111111"));
        assert!(ch.is_number_allowed("+2222222222"));
        assert!(ch.is_number_allowed("+3333333333"));
        assert!(!ch.is_number_allowed("+4444444444"));
    }

    #[test]
    fn whatsapp_number_allowed_case_sensitive() {
        // Phone numbers should be exact match
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["+1234567890".into()],
        );
        assert!(ch.is_number_allowed("+1234567890"));
        // Different number should not match
        assert!(!ch.is_number_allowed("+1234567891"));
    }

    #[test]
    fn whatsapp_parse_phone_already_has_plus() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["+1234567890".into()],
        );
        // If API sends with +, we should still handle it
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": [{
                            "from": "+1234567890",
                            "timestamp": "1",
                            "type": "text",
                            "text": { "body": "Hi" }
                        }]
                    }
                }]
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert_eq!(msgs.len(), 1);
        assert_eq!(msgs[0].sender, "+1234567890");
    }

    #[test]
    fn whatsapp_channel_fields_stored_correctly() {
        let ch = WhatsAppChannel::new(
            "my-access-token".into(),
            "phone-id-123".into(),
            "my-verify-token".into(),
            vec!["+111".into(), "+222".into()],
        );
        assert_eq!(ch.verify_token(), "my-verify-token");
        assert!(ch.is_number_allowed("+111"));
        assert!(ch.is_number_allowed("+222"));
        assert!(!ch.is_number_allowed("+333"));
    }

    #[test]
    fn whatsapp_parse_empty_messages_array() {
        let ch = make_channel();
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": []
                    }
                }]
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert!(msgs.is_empty());
    }

    #[test]
    fn whatsapp_parse_empty_entry_array() {
        let ch = make_channel();
        let payload = serde_json::json!({
            "entry": []
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert!(msgs.is_empty());
    }

    #[test]
    fn whatsapp_parse_empty_changes_array() {
        let ch = make_channel();
        let payload = serde_json::json!({
            "entry": [{
                "changes": []
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert!(msgs.is_empty());
    }

    #[test]
    fn whatsapp_parse_newlines_preserved() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["*".into()],
        );
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": [{
                            "from": "111",
                            "timestamp": "1",
                            "type": "text",
                            "text": { "body": "Line 1\nLine 2\nLine 3" }
                        }]
                    }
                }]
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert_eq!(msgs.len(), 1);
        assert_eq!(msgs[0].content, "Line 1\nLine 2\nLine 3");
    }

    #[test]
    fn whatsapp_parse_special_characters() {
        let ch = WhatsAppChannel::new(
            "tok".into(),
            "123".into(),
            "ver".into(),
            vec!["*".into()],
        );
        let payload = serde_json::json!({
            "entry": [{
                "changes": [{
                    "value": {
                        "messages": [{
                            "from": "111",
                            "timestamp": "1",
                            "type": "text",
                            "text": { "body": "<script>alert('xss')</script> & \"quotes\" 'apostrophe'" }
                        }]
                    }
                }]
            }]
        });
        let msgs = ch.parse_webhook_payload(&payload);
        assert_eq!(msgs.len(), 1);
        assert_eq!(msgs[0].content, "<script>alert('xss')</script> & \"quotes\" 'apostrophe'");
    }
}