"""
Superadmin tunnel management API endpoints.
"""

from typing import Annotated, Optional

from fastapi import APIRouter, Depends, HTTPException, status, WebSocket, WebSocketDisconnect, Request
from sqlalchemy.ext.asyncio import AsyncSession
from pydantic import BaseModel
from sqlalchemy import select
from starlette.responses import StreamingResponse, Response
import httpx
import asyncio

from app.api.deps import get_current_superadmin
from app.core.database import get_db
from app.models.device import Device
from app.models.user import User
from app.services.tunnel_service import tunnel_service
import socket


router = APIRouter(prefix="/tunnels", tags=["superadmin-tunnels"])


async def _allocate_tunnel_port(
    db: AsyncSession,
    device: Device,
    tunnel_type: str,
    port_range: tuple[int, int]
) -> int:
    """
    Allocate a free port for tunnel.
    Strategy: Use device's simple_id to calculate deterministic port offset.
    """
    # Calculate port based on device simple_id for deterministic allocation
    start_port, end_port = port_range
    port_offset = device.simple_id % (end_port - start_port + 1)
    allocated_port = start_port + port_offset

    # Verify port is free on the system
    def is_port_free(port: int) -> bool:
        try:
            with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
                s.bind(('', port))
                return True
        except OSError:
            return False

    # If calculated port is taken, find next free port
    attempts = 0
    while not is_port_free(allocated_port) and attempts < 1000:
        allocated_port += 1
        if allocated_port > end_port:
            allocated_port = start_port
        attempts += 1

    if attempts >= 1000:
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail="No free ports available for tunnel"
        )

    return allocated_port


class TunnelEnableResponse(BaseModel):
    """Response when enabling tunnel"""
    session_uuid: str
    device_id: str
    tunnel_type: str
    status: str


class TunnelStatusResponse(BaseModel):
    """Tunnel session status response"""
    session_uuid: str
    status: str  # "waiting" | "ready" | "failed"
    device_tunnel_port: Optional[int] = None
    ttyd_port: Optional[int] = None
    tunnel_url: Optional[str] = None


@router.get("/sessions")
async def list_all_sessions(
    current_user: Annotated[User, Depends(get_current_superadmin)]
):
    """
    Debug endpoint: List all active tunnel sessions in memory.
    """
    sessions = []
    for uuid, session in tunnel_service.sessions.items():
        sessions.append({
            "uuid": uuid,
            "device_id": session.device_id,
            "tunnel_type": session.tunnel_type,
            "status": session.status,
            "created_at": session.created_at.isoformat(),
            "expires_at": session.expires_at.isoformat(),
            "last_heartbeat": session.last_heartbeat.isoformat() if session.last_heartbeat else None,
            "ttyd_port": session.ttyd_port,
            "ttyd_pid": session.ttyd_pid,
            "device_tunnel_port": session.device_tunnel_port
        })
    return {
        "total": len(sessions),
        "sessions": sessions
    }


@router.post("/devices/{device_id}/{tunnel_type}")
async def enable_tunnel(
    device_id: int,
    tunnel_type: str,
    db: Annotated[AsyncSession, Depends(get_db)],
    current_user: Annotated[User, Depends(get_current_superadmin)]
) -> TunnelEnableResponse:
    """
    Enable SSH or Dashboard tunnel for device.
    Creates session and triggers device to connect tunnel.

    Args:
        device_id: Device numeric ID
        tunnel_type: "ssh" or "dashboard"

    Returns:
        session_uuid: UUID for polling status
    """
    if tunnel_type not in ["ssh", "dashboard"]:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="tunnel_type must be 'ssh' or 'dashboard'"
        )

    # Get device
    result = await db.execute(
        select(Device).where(Device.id == device_id)
    )
    device = result.scalar_one_or_none()

    if not device:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Device not found"
        )

    # Allocate port for tunnel
    if tunnel_type == "ssh":
        # SSH tunnel ports: 50000-59999
        port_range = (50000, 59999)
    else:
        # Dashboard tunnel ports: 60000-65535
        port_range = (60000, 65535)

    # Find free port (simple sequential allocation)
    allocated_port = await _allocate_tunnel_port(db, device, tunnel_type, port_range)

    # Create tunnel session
    session = tunnel_service.create_session(
        device_id=device.mac_address,
        admin_user=current_user.email,
        tunnel_type=tunnel_type
    )

    # Update device config to enable tunnel with allocated port
    if device.config is None:
        device.config = {}

    tunnel_key = f"{tunnel_type}_tunnel"
    if tunnel_key not in device.config:
        device.config[tunnel_key] = {}

    device.config[tunnel_key]["enabled"] = True
    device.config[tunnel_key]["remote_port"] = allocated_port
    device.config[tunnel_key]["timeout_minutes"] = 120  # Tunnel will auto-stop after 120 minutes

    # Copy other tunnel settings from default
    if "server" not in device.config[tunnel_key]:
        device.config[tunnel_key]["server"] = "ms.e-bash.ru"
        device.config[tunnel_key]["port"] = 2223
        device.config[tunnel_key]["user"] = "tunnel"
        device.config[tunnel_key]["keepalive_interval"] = 30

    # Mark as modified (SQLAlchemy JSON field)
    from sqlalchemy.orm import attributes
    attributes.flag_modified(device, "config")

    await db.commit()

    print(f"[tunnel] Enabled {tunnel_type} tunnel for {device.mac_address} on port {allocated_port}")

    return TunnelEnableResponse(
        session_uuid=session.uuid,
        device_id=device.mac_address,
        tunnel_type=tunnel_type,
        status="waiting"
    )


@router.get("/sessions/{session_uuid}/status")
async def get_tunnel_status(
    session_uuid: str,
    current_user: Annotated[User, Depends(get_current_superadmin)]
) -> TunnelStatusResponse:
    """
    Poll tunnel session status.

    Returns:
        - waiting: Device not yet connected
        - ready: Tunnel connected, ttyd spawned
        - failed: Session expired or failed
    """
    session = tunnel_service.get_session(session_uuid)

    if not session:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Session not found or expired"
        )

    # Build response
    response = TunnelStatusResponse(
        session_uuid=session.uuid,
        status=session.status,
        device_tunnel_port=session.device_tunnel_port,
        ttyd_port=session.ttyd_port
    )

    # If ready, return appropriate URL based on tunnel type
    if session.status == "ready":
        if session.tunnel_type == "ssh" and session.ttyd_port:
            response.tunnel_url = f"/admin/ssh/{session.uuid}"
        elif session.tunnel_type == "dashboard" and session.device_tunnel_port:
            response.tunnel_url = f"/admin/dashboard/{session.uuid}"

    return response


@router.post("/sessions/{session_uuid}/heartbeat")
async def session_heartbeat(
    session_uuid: str,
    current_user: Annotated[User, Depends(get_current_superadmin)]
):
    """
    Browser sends heartbeat every 30 seconds to keep session alive.
    """
    success = tunnel_service.update_heartbeat(session_uuid)

    if not success:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Session not found"
        )

    return {"success": True}


@router.websocket("/sessions/{session_uuid}/terminal/ws")
async def tunnel_terminal_websocket(
    websocket: WebSocket,
    session_uuid: str
):
    """
    WebSocket proxy to ttyd on localhost.
    """
    session = tunnel_service.get_session(session_uuid)
    if not session or not session.ttyd_port:
        print(f"[tunnel] WS: Session not found or no ttyd port: {session_uuid}")
        await websocket.close(code=1008, reason="Session not found")
        return

    print(f"[tunnel] WS: Accepting connection for session {session_uuid}, ttyd port {session.ttyd_port}")
    # ttyd uses "tty" WebSocket subprotocol
    await websocket.accept(subprotocol="tty")

    # Connect to ttyd WebSocket
    import websockets
    try:
        ttyd_url = f'ws://localhost:{session.ttyd_port}/ws'
        print(f"[tunnel] WS: Connecting to ttyd at {ttyd_url}")

        # Connect to ttyd with "tty" subprotocol
        async with websockets.connect(ttyd_url, subprotocols=["tty"]) as ttyd_ws:
            print(f"[tunnel] WS: Connected to ttyd successfully")

            # Proxy messages both ways
            async def forward_to_ttyd():
                try:
                    while True:
                        message = await websocket.receive()
                        print(f"[tunnel] WS: Received from browser: {message.keys()}")

                        if 'bytes' in message:
                            data = message['bytes']
                            print(f"[tunnel] WS: Browser -> ttyd ({len(data)} bytes)")
                            await ttyd_ws.send(data)
                        elif 'text' in message:
                            data = message['text']
                            print(f"[tunnel] WS: Browser -> ttyd ({len(data)} chars text)")
                            await ttyd_ws.send(data)
                        elif 'websocket.disconnect' in message:
                            print(f"[tunnel] WS: Browser sent disconnect")
                            break
                except WebSocketDisconnect:
                    print(f"[tunnel] WS: Browser disconnected (exception)")
                except Exception as e:
                    print(f"[tunnel] WS: Error forwarding to ttyd: {e}")
                    import traceback
                    traceback.print_exc()

            async def forward_from_ttyd():
                try:
                    async for message in ttyd_ws:
                        if isinstance(message, bytes):
                            print(f"[tunnel] WS: ttyd -> Browser ({len(message)} bytes)")
                            await websocket.send_bytes(message)
                        else:
                            print(f"[tunnel] WS: ttyd -> Browser ({len(message)} chars text)")
                            await websocket.send_text(message)
                except Exception as e:
                    print(f"[tunnel] WS: Error forwarding from ttyd: {e}")
                    import traceback
                    traceback.print_exc()

            await asyncio.gather(forward_to_ttyd(), forward_from_ttyd(), return_exceptions=True)
            print(f"[tunnel] WS: Proxy loop ended")

    except Exception as e:
        print(f"[tunnel] WS: Proxy error: {e}")
        import traceback
        traceback.print_exc()
        try:
            await websocket.close(code=1011, reason="Proxy error")
        except:
            pass


@router.websocket("/sessions/{session_uuid}/dashboard/api/ws")
async def tunnel_dashboard_websocket(
    websocket: WebSocket,
    session_uuid: str
):
    """
    WebSocket proxy to device dashboard WebSocket.
    """
    session = tunnel_service.get_session(session_uuid)
    if not session or not session.device_tunnel_port:
        print(f"[tunnel] Dashboard WS: Session not found: {session_uuid}")
        await websocket.close(code=1008, reason="Session not found")
        return

    print(f"[tunnel] Dashboard WS: Accepting connection for session {session_uuid}")
    await websocket.accept()

    # Connect to device dashboard WebSocket
    import websockets
    try:
        device_ws_url = f'ws://localhost:{session.device_tunnel_port}/api/ws'
        print(f"[tunnel] Dashboard WS: Connecting to {device_ws_url}")

        async with websockets.connect(device_ws_url) as device_ws:
            print(f"[tunnel] Dashboard WS: Connected successfully")

            # Proxy messages both ways
            async def forward_to_device():
                try:
                    while True:
                        message = await websocket.receive()
                        if 'bytes' in message:
                            await device_ws.send(message['bytes'])
                        elif 'text' in message:
                            await device_ws.send(message['text'])
                        elif 'websocket.disconnect' in message:
                            break
                except WebSocketDisconnect:
                    print(f"[tunnel] Dashboard WS: Browser disconnected")
                except Exception as e:
                    print(f"[tunnel] Dashboard WS: Error forwarding to device: {e}")

            async def forward_from_device():
                try:
                    async for message in device_ws:
                        if isinstance(message, bytes):
                            await websocket.send_bytes(message)
                        else:
                            await websocket.send_text(message)
                except Exception as e:
                    print(f"[tunnel] Dashboard WS: Error forwarding from device: {e}")

            await asyncio.gather(forward_to_device(), forward_from_device(), return_exceptions=True)
            print(f"[tunnel] Dashboard WS: Proxy ended")

    except Exception as e:
        print(f"[tunnel] Dashboard WS: Proxy error: {e}")
        try:
            await websocket.close(code=1011, reason="Proxy error")
        except:
            pass


@router.api_route("/sessions/{session_uuid}/terminal/{path:path}", methods=["GET", "POST"])
async def tunnel_terminal_proxy(
    session_uuid: str,
    path: str,
    request: Request
):
    """
    Full HTTP proxy to ttyd (including token, ws, etc).
    Security: Session was created by superadmin, UUID is secret.
    Proxies /terminal/{path} to http://localhost:ttyd_port/{path}
    """
    session = tunnel_service.get_session(session_uuid)
    if not session or not session.ttyd_port:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Terminal session not found"
        )

    # Proxy request to ttyd
    url = f'http://localhost:{session.ttyd_port}/{path}'
    print(f"[tunnel] HTTP proxy: {request.url.path} -> {url}")

    async with httpx.AsyncClient() as client:
        resp = await client.request(
            method=request.method,
            url=url,
            headers=dict(request.headers),
            params=request.query_params,
        )

        return Response(
            content=resp.content,
            status_code=resp.status_code,
            headers=dict(resp.headers)
        )


@router.api_route("/sessions/{session_uuid}/dashboard/{path:path}", methods=["GET", "POST"])
async def tunnel_dashboard_proxy(
    session_uuid: str,
    path: str,
    request: Request
):
    """
    Proxy Dashboard HTTP/WebSocket to device via tunnel.
    Security: Session was created by superadmin, UUID is secret.
    """
    session = tunnel_service.get_session(session_uuid)
    if not session or not session.device_tunnel_port:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Dashboard session not found"
        )

    # Proxy to device dashboard through tunnel
    # Normalize path - avoid double slashes
    clean_path = path if path and path != '/' else ''
    url = f'http://localhost:{session.device_tunnel_port}/{clean_path}'
    print(f"[tunnel] Dashboard proxy: {request.url.path} -> {url}")

    async with httpx.AsyncClient() as client:
        resp = await client.request(
            method=request.method,
            url=url,
            headers={k: v for k, v in request.headers.items() if k.lower() not in ('host',)},
            params=request.query_params,
            content=await request.body()
        )

        # Replace paths in HTML/JS/CSS files
        content_type = resp.headers.get('content-type', '')
        should_replace = (
            (not path or path == '/') and 'text/html' in content_type
        ) or (
            'javascript' in content_type or 'css' in content_type
        )

        if should_replace:
            try:
                content = resp.text
                base_url = f'/api/v1/superadmin/tunnels/sessions/{session_uuid}/dashboard/'

                # Replace absolute paths with proxied paths
                import re

                # First: Replace API paths (in JS/HTML)
                # Replace /api/* paths but avoid double-replacing
                # Use a unique marker to avoid replacing already-replaced paths
                marker = f'__DASHBOARD__{session_uuid}__'

                # Replace all /api/ with marker first
                content = re.sub(r'(?<!/v1/superadmin/tunnels)/api/', rf'{marker}/api/', content)

                # Now replace marker with full path
                content = content.replace(marker, base_url.rstrip('/'))

                # Second: Replace href/src="/..." -> href/src="/api/v1/.../dashboard/..." (HTML only)
                if 'text/html' in content_type:
                    content = re.sub(r'(href|src)="/', rf'\1="{base_url}', content)

                headers = {
                    k: v for k, v in resp.headers.items()
                    if k.lower() not in ('content-length', 'content-encoding')
                }

                if 'text/html' in content_type:
                    from starlette.responses import HTMLResponse
                    return HTMLResponse(content=content, headers=headers)
                else:
                    return Response(content=content.encode('utf-8'), headers=headers)
            except Exception as e:
                print(f"[tunnel] Dashboard path replacement error: {e}")
                # Fall through to return original response

        return Response(
            content=resp.content,
            status_code=resp.status_code,
            headers={k: v for k, v in resp.headers.items() if k.lower() not in ('content-length', 'content-encoding')}
        )


@router.get("/sessions/{session_uuid}/terminal")
async def tunnel_terminal_html(
    session_uuid: str
):
    """
    Return ttyd HTML with modified URLs.
    Security: Session was created by superadmin, UUID is secret.
    """
    session = tunnel_service.get_session(session_uuid)
    if not session or not session.ttyd_port:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Terminal session not found"
        )

    # Fetch ttyd HTML and modify URLs to work through our proxy
    async with httpx.AsyncClient() as client:
        try:
            resp = await client.get(f'http://localhost:{session.ttyd_port}/')
            print(f"[tunnel] HTML: ttyd returned status {resp.status_code}")

            if resp.status_code != 200:
                print(f"[tunnel] HTML: ttyd error: {resp.text[:200]}")
                raise HTTPException(
                    status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
                    detail="Terminal not ready"
                )

            html = resp.text

            # Prefix for all ttyd resources
            prefix = f'/api/v1/superadmin/tunnels/sessions/{session_uuid}/terminal'

            # Replace relative URLs with proxied URLs
            html = html.replace('src="/', f'src="{prefix}/')
            html = html.replace('href="/', f'href="{prefix}/')

            # Replace WebSocket URL
            # ttyd uses: new WebSocket(url) where url is like "ws://host/ws"
            # We need to replace it to go through our proxy
            import re
            # Find WebSocket URL construction in JavaScript
            ws_before = html.count('new WebSocket')
            # Use wss:// for HTTPS, ws:// for HTTP - construct from request would be ideal
            # For now, replace with relative WebSocket that browser will resolve
            html = re.sub(
                r'(new WebSocket\([\'"])(ws[s]?://[^/]+)(/ws[\'"])',
                rf"\1' + (location.protocol === 'https:' ? 'wss://' : 'ws://') + location.host + '{prefix}\3",
                html
            )
            ws_after = html.count("location.host")
            print(f"[tunnel] HTML: replaced {ws_after} WebSocket URLs (found {ws_before} total)")

            from starlette.responses import HTMLResponse
            # Don't copy Content-Length or Content-Encoding since we modified the HTML
            # (ttyd returns compressed, we return uncompressed modified HTML)
            headers = {
                k: v for k, v in resp.headers.items()
                if k.lower() not in ('content-length', 'content-encoding')
            }
            return HTMLResponse(content=html, headers=headers)
        except Exception as e:
            print(f"[tunnel] HTML: exception: {e}")
            raise HTTPException(
                status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
                detail=f"Failed to fetch terminal: {str(e)}"
            )