use std::sync::Arc;

use crate::chat::transport::matrix::{ConversationEntry, ConversationRole, RoomConversation};
use crate::http::context::{PermissionDecision};
use crate::slog;
use super::WhatsAppWebhookContext;
use super::format::{chunk_for_whatsapp, markdown_to_whatsapp};
use super::history::save_whatsapp_history;

/// Returns `true` if the message body should be interpreted as permission approval.
fn is_permission_approval(body: &str) -> bool {
    let trimmed = body.trim().to_ascii_lowercase();
    matches!(
        trimmed.as_str(),
        "yes" | "y" | "approve" | "allow" | "ok"
    )
}

/// Dispatch an incoming WhatsApp message to bot commands.
pub(super) async fn handle_incoming_message(ctx: &WhatsAppWebhookContext, sender: &str, message: &str) {
    use crate::chat::commands::{CommandDispatch, try_handle_command};

    // Allowlist check: when configured, silently ignore unauthorized senders.
    if !ctx.allowed_phones.is_empty()
        && !ctx.allowed_phones.iter().any(|p| p == sender)
    {
        slog!("[whatsapp] Ignoring message from unauthorized sender: {sender}");
        return;
    }

    // Record this inbound message to keep the 24-hour window open.
    ctx.window_tracker.record_message(sender);

    // If there is a pending permission prompt for this sender, interpret the
    // message as a yes/no response instead of starting a new command/LLM flow.
    {
        let mut pending = ctx.pending_perm_replies.lock().await;
        if let Some(tx) = pending.remove(sender) {
            let decision = if is_permission_approval(message) {
                PermissionDecision::Approve
            } else {
                PermissionDecision::Deny
            };
            let _ = tx.send(decision);
            let confirmation = if decision == PermissionDecision::Approve {
                "Permission approved."
            } else {
                "Permission denied."
            };
            let formatted = markdown_to_whatsapp(confirmation);
            let _ = ctx.transport.send_message(sender, &formatted, "").await;
            return;
        }
    }

    let dispatch = CommandDispatch {
        bot_name: &ctx.bot_name,
        bot_user_id: &ctx.bot_user_id,
        project_root: &ctx.project_root,
        agents: &ctx.agents,
        ambient_rooms: &ctx.ambient_rooms,
        room_id: sender,
    };

    if let Some(response) = try_handle_command(&dispatch, message) {
        slog!("[whatsapp] Sending command response to {sender}");
        let formatted = markdown_to_whatsapp(&response);
        if let Err(e) = ctx.transport.send_message(sender, &formatted, "").await {
            slog!("[whatsapp] Failed to send reply to {sender}: {e}");
        }
        return;
    }

    // Check for async commands (htop, delete).
    if let Some(htop_cmd) = crate::chat::transport::matrix::htop::extract_htop_command(
        message,
        &ctx.bot_name,
        &ctx.bot_user_id,
    ) {
        use crate::chat::transport::matrix::htop::HtopCommand;
        slog!("[whatsapp] Handling htop command from {sender}");
        match htop_cmd {
            HtopCommand::Stop => {
                // htop stop — no-op on WhatsApp since there's no persistent
                // editable message; just acknowledge.
                let _ = ctx
                    .transport
                    .send_message(sender, "htop stopped.", "")
                    .await;
            }
            HtopCommand::Start { duration_secs } => {
                // On WhatsApp, send a single snapshot instead of a live-updating
                // dashboard since we can't edit messages.
                let snapshot = crate::chat::transport::matrix::htop::build_htop_message(
                    &ctx.agents,
                    0,
                    duration_secs,
                );
                let _ = ctx.transport.send_message(sender, &snapshot, "").await;
            }
        }
        return;
    }

    if let Some(del_cmd) = crate::chat::transport::matrix::delete::extract_delete_command(
        message,
        &ctx.bot_name,
        &ctx.bot_user_id,
    ) {
        let response = match del_cmd {
            crate::chat::transport::matrix::delete::DeleteCommand::Delete { story_number } => {
                slog!("[whatsapp] Handling delete command from {sender}: story {story_number}");
                crate::chat::transport::matrix::delete::handle_delete(
                    &ctx.bot_name,
                    &story_number,
                    &ctx.project_root,
                    &ctx.agents,
                )
                .await
            }
            crate::chat::transport::matrix::delete::DeleteCommand::BadArgs => {
                format!("Usage: `{} delete <number>`", ctx.bot_name)
            }
        };
        let _ = ctx.transport.send_message(sender, &response, "").await;
        return;
    }

    if crate::chat::transport::matrix::rebuild::extract_rebuild_command(
        message,
        &ctx.bot_name,
        &ctx.bot_user_id,
    )
    .is_some()
    {
        slog!("[whatsapp] Handling rebuild command from {sender}");
        let ack = "Rebuilding server… this may take a moment.";
        let _ = ctx.transport.send_message(sender, ack, "").await;
        let response = crate::chat::transport::matrix::rebuild::handle_rebuild(
            &ctx.bot_name,
            &ctx.project_root,
            &ctx.agents,
        )
        .await;
        let _ = ctx.transport.send_message(sender, &response, "").await;
        return;
    }

    if let Some(rmtree_cmd) = crate::chat::transport::matrix::rmtree::extract_rmtree_command(
        message,
        &ctx.bot_name,
        &ctx.bot_user_id,
    ) {
        let response = match rmtree_cmd {
            crate::chat::transport::matrix::rmtree::RmtreeCommand::Rmtree { story_number } => {
                slog!("[whatsapp] Handling rmtree command from {sender}: story {story_number}");
                crate::chat::transport::matrix::rmtree::handle_rmtree(
                    &ctx.bot_name,
                    &story_number,
                    &ctx.project_root,
                    &ctx.agents,
                )
                .await
            }
            crate::chat::transport::matrix::rmtree::RmtreeCommand::BadArgs => {
                format!("Usage: `{} rmtree <number>`", ctx.bot_name)
            }
        };
        let _ = ctx.transport.send_message(sender, &response, "").await;
        return;
    }

    if crate::chat::transport::matrix::reset::extract_reset_command(
        message,
        &ctx.bot_name,
        &ctx.bot_user_id,
    )
    .is_some()
    {
        slog!("[whatsapp] Handling reset command from {sender}");
        {
            let mut guard = ctx.history.lock().await;
            let conv = guard.entry(sender.to_string()).or_insert_with(RoomConversation::default);
            conv.session_id = None;
            conv.entries.clear();
            save_whatsapp_history(&ctx.project_root, &guard);
        }
        let _ = ctx
            .transport
            .send_message(sender, "Session cleared.", "")
            .await;
        return;
    }

    if let Some(start_cmd) = crate::chat::transport::matrix::start::extract_start_command(
        message,
        &ctx.bot_name,
        &ctx.bot_user_id,
    ) {
        let response = match start_cmd {
            crate::chat::transport::matrix::start::StartCommand::Start {
                story_number,
                agent_hint,
            } => {
                slog!("[whatsapp] Handling start command from {sender}: story {story_number}");
                crate::chat::transport::matrix::start::handle_start(
                    &ctx.bot_name,
                    &story_number,
                    agent_hint.as_deref(),
                    &ctx.project_root,
                    &ctx.agents,
                )
                .await
            }
            crate::chat::transport::matrix::start::StartCommand::BadArgs => {
                format!("Usage: `{} start <number>`", ctx.bot_name)
            }
        };
        let _ = ctx.transport.send_message(sender, &response, "").await;
        return;
    }

    // No command matched — forward to LLM for conversational response.
    slog!("[whatsapp] No command matched, forwarding to LLM for {sender}");
    handle_llm_message(ctx, sender, message).await;
}

/// Forward a message to Claude Code and send the response back via WhatsApp.
async fn handle_llm_message(ctx: &WhatsAppWebhookContext, sender: &str, user_message: &str) {
    use crate::chat::util::drain_complete_paragraphs;
    use crate::llm::providers::claude_code::{ClaudeCodeProvider, ClaudeCodeResult};
    use std::sync::atomic::{AtomicBool, Ordering};
    use tokio::sync::watch;

    // Look up existing session ID for this sender.
    let resume_session_id: Option<String> = {
        let guard = ctx.history.lock().await;
        guard.get(sender).and_then(|conv| conv.session_id.clone())
    };

    let bot_name = &ctx.bot_name;
    let prompt = format!(
        "[Your name is {bot_name}. Refer to yourself as {bot_name}, not Claude.]\n\n{sender}: {user_message}"
    );

    let provider = ClaudeCodeProvider::new();
    let (_cancel_tx, mut cancel_rx) = watch::channel(false);

    // Channel for sending complete chunks to the WhatsApp posting task.
    let (msg_tx, mut msg_rx) = tokio::sync::mpsc::unbounded_channel::<String>();
    let msg_tx_for_callback = msg_tx.clone();

    // Spawn a task to post messages as they arrive.
    let post_transport = Arc::clone(&ctx.transport);
    let post_sender = sender.to_string();
    let post_task = tokio::spawn(async move {
        while let Some(chunk) = msg_rx.recv().await {
            // Convert Markdown to WhatsApp formatting, then split into sized chunks.
            let formatted = markdown_to_whatsapp(&chunk);
            for part in chunk_for_whatsapp(&formatted) {
                let _ = post_transport.send_message(&post_sender, &part, "").await;
            }
        }
    });

    // Shared buffer between the sync token callback and the async scope.
    let buffer = Arc::new(std::sync::Mutex::new(String::new()));
    let buffer_for_callback = Arc::clone(&buffer);
    let sent_any_chunk = Arc::new(AtomicBool::new(false));
    let sent_any_chunk_for_callback = Arc::clone(&sent_any_chunk);

    let project_root_str = ctx.project_root.to_string_lossy().to_string();
    let chat_fut = provider.chat_stream(
        &prompt,
        &project_root_str,
        resume_session_id.as_deref(),
        None,
        &mut cancel_rx,
        move |token| {
            let mut buf = buffer_for_callback.lock().unwrap();
            buf.push_str(token);
            let paragraphs = drain_complete_paragraphs(&mut buf);
            for chunk in paragraphs {
                sent_any_chunk_for_callback.store(true, Ordering::Relaxed);
                let _ = msg_tx_for_callback.send(chunk);
            }
        },
        |_thinking| {},
        |_activity| {},
    );
    tokio::pin!(chat_fut);

    // Lock the permission receiver for the duration of this chat session.
    let mut perm_rx_guard = ctx.perm_rx.lock().await;

    let result = loop {
        tokio::select! {
            r = &mut chat_fut => break r,

            Some(perm_fwd) = perm_rx_guard.recv() => {
                let prompt_msg = format!(
                    "*Permission Request*\n\nTool: `{}`\n```json\n{}\n```\n\nReply *yes* to approve or *no* to deny.",
                    perm_fwd.tool_name,
                    serde_json::to_string_pretty(&perm_fwd.tool_input)
                        .unwrap_or_else(|_| perm_fwd.tool_input.to_string()),
                );
                let formatted = markdown_to_whatsapp(&prompt_msg);
                for part in chunk_for_whatsapp(&formatted) {
                    let _ = ctx.transport.send_message(sender, &part, "").await;
                }

                // Store the response sender so the incoming message handler
                // can resolve it when the user replies yes/no.
                ctx.pending_perm_replies
                    .lock()
                    .await
                    .insert(sender.to_string(), perm_fwd.response_tx);

                // Spawn a timeout task: auto-deny if the user does not respond.
                let pending = Arc::clone(&ctx.pending_perm_replies);
                let timeout_sender = sender.to_string();
                let timeout_transport = Arc::clone(&ctx.transport);
                let timeout_secs = ctx.permission_timeout_secs;
                tokio::spawn(async move {
                    tokio::time::sleep(std::time::Duration::from_secs(timeout_secs)).await;
                    if let Some(tx) = pending.lock().await.remove(&timeout_sender) {
                        let _ = tx.send(PermissionDecision::Deny);
                        let msg = "Permission request timed out — denied (fail-closed).";
                        let _ = timeout_transport.send_message(&timeout_sender, msg, "").await;
                    }
                });
            }
        }
    };
    drop(perm_rx_guard);

    // Flush remaining text.
    let remaining = buffer.lock().unwrap().trim().to_string();
    let did_send_any = sent_any_chunk.load(Ordering::Relaxed);

    let (assistant_reply, new_session_id) = match result {
        Ok(ClaudeCodeResult {
            messages,
            session_id,
        }) => {
            let reply = if !remaining.is_empty() {
                let _ = msg_tx.send(remaining.clone());
                remaining
            } else if !did_send_any {
                let last_text = messages
                    .iter()
                    .rev()
                    .find(|m| m.role == crate::llm::types::Role::Assistant && !m.content.is_empty())
                    .map(|m| m.content.clone())
                    .unwrap_or_default();
                if !last_text.is_empty() {
                    let _ = msg_tx.send(last_text.clone());
                }
                last_text
            } else {
                remaining
            };
            slog!("[whatsapp] session_id from chat_stream: {:?}", session_id);
            (reply, session_id)
        }
        Err(e) => {
            slog!("[whatsapp] LLM error: {e}");
            let err_msg = format!("Error processing your request: {e}");
            let _ = msg_tx.send(err_msg.clone());
            (err_msg, None)
        }
    };

    // Signal the posting task to finish and wait for it.
    drop(msg_tx);
    let _ = post_task.await;

    // Record this exchange in conversation history.
    if !assistant_reply.starts_with("Error processing") {
        let mut guard = ctx.history.lock().await;
        let conv = guard.entry(sender.to_string()).or_default();

        if new_session_id.is_some() {
            conv.session_id = new_session_id;
        }

        conv.entries.push(ConversationEntry {
            role: ConversationRole::User,
            sender: sender.to_string(),
            content: user_message.to_string(),
        });
        conv.entries.push(ConversationEntry {
            role: ConversationRole::Assistant,
            sender: String::new(),
            content: assistant_reply,
        });

        // Trim to configured maximum.
        if conv.entries.len() > ctx.history_size {
            let excess = conv.entries.len() - ctx.history_size;
            conv.entries.drain(..excess);
        }

        save_whatsapp_history(&ctx.project_root, &guard);
    }
}

// ── Tests ───────────────────────────────────────────────────────────────

#[cfg(test)]
mod tests {
    use crate::agents::AgentPool;
    use crate::io::watcher::WatcherEvent;
    use crate::chat::transport::matrix::{ConversationEntry, ConversationRole, RoomConversation};
    use super::super::history::{MessagingWindowTracker, WhatsAppConversationHistory};
    use super::super::WhatsAppWebhookContext;
    use super::*;
    use std::collections::HashMap;
    use std::sync::Arc;
    use tokio::sync::Mutex as TokioMutex;

    /// Build a minimal WhatsAppWebhookContext for allowlist tests.
    fn make_ctx_with_allowlist(
        allowed_phones: Vec<String>,
    ) -> Arc<WhatsAppWebhookContext> {
        struct NullTransport;

        #[async_trait::async_trait]
        impl crate::chat::ChatTransport for NullTransport {
            async fn send_message(
                &self,
                _room: &str,
                _plain: &str,
                _html: &str,
            ) -> Result<crate::chat::MessageId, String> {
                Ok(String::new())
            }
            async fn edit_message(
                &self,
                _room: &str,
                _id: &str,
                _plain: &str,
                _html: &str,
            ) -> Result<(), String> {
                Ok(())
            }
            async fn send_typing(&self, _room: &str, _typing: bool) -> Result<(), String> {
                Ok(())
            }
        }

        let tmp = tempfile::tempdir().unwrap();
        let (tx, _rx) = tokio::sync::broadcast::channel::<WatcherEvent>(16);
        let agents = Arc::new(AgentPool::new(3999, tx));
        let tracker = Arc::new(MessagingWindowTracker::new());
        let (_perm_tx, perm_rx) = tokio::sync::mpsc::unbounded_channel();
        Arc::new(WhatsAppWebhookContext {
            verify_token: "tok".to_string(),
            provider: "meta".to_string(),
            transport: Arc::new(NullTransport),
            project_root: tmp.path().to_path_buf(),
            agents,
            bot_name: "Bot".to_string(),
            bot_user_id: "whatsapp-bot".to_string(),
            ambient_rooms: Arc::new(std::sync::Mutex::new(Default::default())),
            history: Arc::new(tokio::sync::Mutex::new(Default::default())),
            history_size: 20,
            window_tracker: tracker,
            allowed_phones,
            perm_rx: Arc::new(tokio::sync::Mutex::new(perm_rx)),
            pending_perm_replies: Arc::new(tokio::sync::Mutex::new(Default::default())),
            permission_timeout_secs: 120,
        })
    }

    // ── Allowlist tests ───────────────────────────────────────────────────

    #[tokio::test]
    async fn allowlist_blocks_unauthorized_sender() {
        let allowed = vec!["+15551111111".to_string()];
        let ctx = make_ctx_with_allowlist(allowed);
        let unauthorized = "+15559999999";

        handle_incoming_message(&ctx, unauthorized, "hello").await;

        // window_tracker is only updated AFTER the allowlist check, so an
        // unauthorized sender must leave the tracker untouched.
        assert!(
            !ctx.window_tracker.is_within_window(unauthorized),
            "unauthorized sender should not have updated the window tracker"
        );
    }

    #[tokio::test]
    async fn allowlist_empty_allows_all_senders() {
        // Empty allowlist = open (backwards compatible).
        let ctx = make_ctx_with_allowlist(vec![]);
        let sender = "+15551234567";

        handle_incoming_message(&ctx, sender, "hello").await;

        // window_tracker.record_message is called right after the allowlist
        // check passes, so the sender should be recorded.
        assert!(
            ctx.window_tracker.is_within_window(sender),
            "sender should be recorded when allowlist is empty"
        );
    }

    #[tokio::test]
    async fn allowlist_allows_listed_sender() {
        let sender = "+15551111111";
        let ctx = make_ctx_with_allowlist(vec![sender.to_string()]);

        handle_incoming_message(&ctx, sender, "hello").await;

        assert!(
            ctx.window_tracker.is_within_window(sender),
            "listed sender should be recorded in the window tracker"
        );
    }

    // ── rebuild command extraction ─────────────────────────────────────

    #[test]
    fn rebuild_command_extracted_from_plain_message() {
        // WhatsApp messages arrive without a bot mention prefix.
        // extract_rebuild_command must recognise "rebuild" by itself.
        let result = crate::chat::transport::matrix::rebuild::extract_rebuild_command(
            "rebuild",
            "Timmy",
            "@timmy:home.local",
        );
        assert!(result.is_some(), "plain 'rebuild' should be recognised");
    }

    #[test]
    fn rebuild_command_extracted_with_bot_name_prefix() {
        let result = crate::chat::transport::matrix::rebuild::extract_rebuild_command(
            "Timmy rebuild",
            "Timmy",
            "@timmy:home.local",
        );
        assert!(result.is_some(), "'Timmy rebuild' should be recognised");
    }

    #[test]
    fn non_rebuild_whatsapp_message_not_extracted() {
        let result = crate::chat::transport::matrix::rebuild::extract_rebuild_command(
            "status",
            "Timmy",
            "@timmy:home.local",
        );
        assert!(result.is_none(), "'status' should not be recognised as rebuild");
    }

    // ── reset command extraction ───────────────────────────────────────

    #[test]
    fn reset_command_extracted_from_plain_message() {
        let result = crate::chat::transport::matrix::reset::extract_reset_command(
            "reset",
            "Timmy",
            "@timmy:home.local",
        );
        assert!(result.is_some(), "plain 'reset' should be recognised");
    }

    #[test]
    fn reset_command_extracted_with_bot_name_prefix() {
        let result = crate::chat::transport::matrix::reset::extract_reset_command(
            "Timmy reset",
            "Timmy",
            "@timmy:home.local",
        );
        assert!(result.is_some(), "'Timmy reset' should be recognised");
    }

    #[tokio::test]
    async fn reset_command_clears_whatsapp_session() {
        let sender = "+15555550100";
        let history: WhatsAppConversationHistory = Arc::new(TokioMutex::new({
            let mut m = HashMap::new();
            m.insert(sender.to_string(), RoomConversation {
                session_id: Some("old-session".to_string()),
                entries: vec![ConversationEntry {
                    role: ConversationRole::User,
                    sender: sender.to_string(),
                    content: "previous message".to_string(),
                }],
            });
            m
        }));

        let tmp = tempfile::tempdir().unwrap();
        let sk = tmp.path().join(".storkit");
        std::fs::create_dir_all(&sk).unwrap();

        {
            let mut guard = history.lock().await;
            let conv = guard.entry(sender.to_string()).or_insert_with(RoomConversation::default);
            conv.session_id = None;
            conv.entries.clear();
            save_whatsapp_history(tmp.path(), &guard);
        }

        let guard = history.lock().await;
        let conv = guard.get(sender).unwrap();
        assert!(conv.session_id.is_none(), "session_id should be cleared");
        assert!(conv.entries.is_empty(), "entries should be cleared");
    }

    #[test]
    fn start_command_extracted_from_plain_message() {
        // WhatsApp messages arrive without a bot mention prefix.
        // extract_start_command must recognise "start 42" by itself.
        let result = crate::chat::transport::matrix::start::extract_start_command(
            "start 42",
            "Timmy",
            "@timmy:home.local",
        );
        assert!(result.is_some(), "plain 'start 42' should be recognised");
        assert_eq!(
            result,
            Some(crate::chat::transport::matrix::start::StartCommand::Start {
                story_number: "42".to_string(),
                agent_hint: None,
            })
        );
    }

    #[test]
    fn start_command_extracted_with_bot_name_prefix() {
        let result = crate::chat::transport::matrix::start::extract_start_command(
            "Timmy start 99",
            "Timmy",
            "@timmy:home.local",
        );
        assert!(result.is_some(), "'Timmy start 99' should be recognised");
    }

    #[test]
    fn non_start_whatsapp_message_not_extracted() {
        let result = crate::chat::transport::matrix::start::extract_start_command(
            "help",
            "Timmy",
            "@timmy:home.local",
        );
        assert!(result.is_none(), "'help' should not be recognised as start");
    }

    // ── rmtree command extraction ──────────────────────────────────────

    #[test]
    fn rmtree_command_extracted_from_plain_message() {
        // WhatsApp messages arrive without a bot mention prefix.
        // extract_rmtree_command must recognise "rmtree 42" by itself.
        let result = crate::chat::transport::matrix::rmtree::extract_rmtree_command(
            "rmtree 42",
            "Timmy",
            "@timmy:home.local",
        );
        assert!(
            matches!(
                result,
                Some(crate::chat::transport::matrix::rmtree::RmtreeCommand::Rmtree { .. })
            ),
            "plain 'rmtree 42' should be recognised"
        );
    }

    #[test]
    fn rmtree_command_extracted_with_bot_name_prefix() {
        let result = crate::chat::transport::matrix::rmtree::extract_rmtree_command(
            "Timmy rmtree 42",
            "Timmy",
            "@timmy:home.local",
        );
        assert!(
            matches!(
                result,
                Some(crate::chat::transport::matrix::rmtree::RmtreeCommand::Rmtree { .. })
            ),
            "'Timmy rmtree 42' should be recognised"
        );
    }

    #[test]
    fn rmtree_command_returns_bad_args_without_number() {
        let result = crate::chat::transport::matrix::rmtree::extract_rmtree_command(
            "rmtree",
            "Timmy",
            "@timmy:home.local",
        );
        assert_eq!(
            result,
            Some(crate::chat::transport::matrix::rmtree::RmtreeCommand::BadArgs)
        );
    }

    #[test]
    fn non_rmtree_whatsapp_message_not_extracted() {
        let result = crate::chat::transport::matrix::rmtree::extract_rmtree_command(
            "status",
            "Timmy",
            "@timmy:home.local",
        );
        assert!(result.is_none(), "'status' should not be recognised as rmtree");
    }
}