//! Tunnel session management endpoints

use axum::{
    extract::{Path, State},
    http::StatusCode,
    Json,
};
use serde::{Deserialize, Serialize};
use tracing::{error, warn};
use uuid::Uuid;

use crate::auth::AuthUser;
use crate::db;
use crate::ws::ServerMessage;
use crate::AppState;

#[derive(Debug, Deserialize)]
pub struct OpenTunnelRequest {
    pub agent_id: String,
}

#[derive(Debug, Serialize)]
pub struct OpenTunnelResponse {
    pub session_id: String,
    pub status: String,
}

#[derive(Debug, Deserialize)]
pub struct CloseTunnelRequest {
    pub session_id: String,
}

#[derive(Debug, Serialize)]
pub struct CloseTunnelResponse {
    pub status: String,
}

#[derive(Debug, Serialize)]
pub struct TunnelStatusResponse {
    pub session_id: String,
    pub agent_id: String,
    pub status: String,
    pub opened_at: String,
    pub last_activity: String,
}

/// POST /api/v1/tunnel/open
/// Open a new tunnel session to an agent
pub async fn open_tunnel(
    State(state): State<AppState>,
    user: AuthUser,
    Json(req): Json<OpenTunnelRequest>,
) -> Result<Json<OpenTunnelResponse>, (StatusCode, String)> {
    // Parse agent_id
    let agent_id = Uuid::parse_str(&req.agent_id)
        .map_err(|_| (StatusCode::BAD_REQUEST, "Invalid agent_id format".to_string()))?;

    // Check if agent exists and is online
    let agent_connected = state.agents.read().await.is_connected(&agent_id);
    if !agent_connected {
        return Err((
            StatusCode::NOT_FOUND,
            "Agent not connected".to_string(),
        ));
    }

    // Check for existing active session
    let has_session = db::has_active_session(&state.db, user.user_id, agent_id)
        .await
        .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()))?;

    if has_session {
        return Err((
            StatusCode::CONFLICT,
            "Active session already exists for this agent".to_string(),
        ));
    }

    // Generate session ID
    let session_id = Uuid::new_v4().to_string();

    // Create session in database
    let _session = db::create_tech_session(&state.db, &session_id, user.user_id, agent_id)
        .await
        .map_err(|e| {
            // Handle unique constraint violation (PostgreSQL error code 23505)
            if let Some(db_err) = e.as_database_error() {
                if db_err.code().as_deref() == Some("23505") {
                    return (
                        StatusCode::CONFLICT,
                        "Active session already exists for this agent".to_string(),
                    );
                }
            }
            error!("Failed to create tunnel session: {}", e);
            (StatusCode::INTERNAL_SERVER_ERROR, e.to_string())
        })?;

    // Send TunnelOpen message to agent via WebSocket
    let tunnel_open_msg = ServerMessage::TunnelOpen {
        session_id: session_id.clone(),
        tech_id: user.user_id,
    };

    let sent = state.agents.read().await.send_to(&agent_id, tunnel_open_msg).await;
    if !sent {
        // Clean up database session if send failed
        if let Err(e) = db::close_tech_session(&state.db, &session_id).await {
            error!("Failed to cleanup session {} after send failure: {}", session_id, e);
        }
        return Err((
            StatusCode::INTERNAL_SERVER_ERROR,
            "Failed to send tunnel open message to agent".to_string(),
        ));
    }

    Ok(Json(OpenTunnelResponse {
        session_id,
        status: "active".to_string(),
    }))
}

/// POST /api/v1/tunnel/close
/// Close an existing tunnel session
pub async fn close_tunnel(
    State(state): State<AppState>,
    user: AuthUser,
    Json(req): Json<CloseTunnelRequest>,
) -> Result<Json<CloseTunnelResponse>, (StatusCode, String)> {
    // Validate session_id format
    if Uuid::parse_str(&req.session_id).is_err() {
        return Err((StatusCode::BAD_REQUEST, "Invalid session_id format".to_string()));
    }

    // Verify session ownership
    let is_owner = db::verify_session_ownership(&state.db, &req.session_id, user.user_id)
        .await
        .map_err(|e| {
            error!("Failed to verify session ownership: {}", e);
            (StatusCode::INTERNAL_SERVER_ERROR, e.to_string())
        })?;

    if !is_owner {
        return Err((
            StatusCode::FORBIDDEN,
            "Session not found or not owned by user".to_string(),
        ));
    }

    // Get session to find agent_id
    let session = db::get_tech_session(&state.db, &req.session_id)
        .await
        .map_err(|e| {
            error!("Failed to get session: {}", e);
            (StatusCode::INTERNAL_SERVER_ERROR, e.to_string())
        })?
        .ok_or((StatusCode::NOT_FOUND, "Session not found".to_string()))?;

    // Send TunnelClose message to agent
    let tunnel_close_msg = ServerMessage::TunnelClose {
        session_id: req.session_id.clone(),
    };

    if !state.agents.read().await.send_to(&session.agent_id, tunnel_close_msg).await {
        warn!(
            "Failed to send TunnelClose message to agent {} for session {}",
            session.agent_id, req.session_id
        );
    }

    // Close session in database
    match db::close_tech_session(&state.db, &req.session_id).await {
        Ok(rows) if rows == 0 => {
            warn!("No rows updated when closing session {}", req.session_id);
        }
        Ok(_) => {}
        Err(e) => {
            error!("Failed to close session in database: {}", e);
            return Err((StatusCode::INTERNAL_SERVER_ERROR, e.to_string()));
        }
    }

    Ok(Json(CloseTunnelResponse {
        status: "closed".to_string(),
    }))
}

/// GET /api/v1/tunnel/status/:session_id
/// Get tunnel session status
pub async fn get_tunnel_status(
    State(state): State<AppState>,
    user: AuthUser,
    Path(session_id): Path<String>,
) -> Result<Json<TunnelStatusResponse>, (StatusCode, String)> {
    // Validate session_id format
    if Uuid::parse_str(&session_id).is_err() {
        return Err((StatusCode::BAD_REQUEST, "Invalid session_id format".to_string()));
    }

    // Verify session ownership
    let is_owner = db::verify_session_ownership(&state.db, &session_id, user.user_id)
        .await
        .map_err(|e| {
            error!("Failed to verify session ownership: {}", e);
            (StatusCode::INTERNAL_SERVER_ERROR, e.to_string())
        })?;

    if !is_owner {
        return Err((
            StatusCode::FORBIDDEN,
            "Session not found or not owned by user".to_string(),
        ));
    }

    // Get session
    let session = db::get_tech_session(&state.db, &session_id)
        .await
        .map_err(|e| {
            error!("Failed to get session: {}", e);
            (StatusCode::INTERNAL_SERVER_ERROR, e.to_string())
        })?
        .ok_or((StatusCode::NOT_FOUND, "Session not found".to_string()))?;

    Ok(Json(TunnelStatusResponse {
        session_id: session.session_id,
        agent_id: session.agent_id.to_string(),
        status: session.status,
        opened_at: session.opened_at.to_rfc3339(),
        last_activity: session.last_activity.to_rfc3339(),
    }))
}