"""Browser API routes for media file browsing."""

import asyncio
import logging
import tempfile
from pathlib import Path
from urllib.parse import unquote

from fastapi import APIRouter, Depends, HTTPException, Query, Response
from fastapi.responses import FileResponse
from pydantic import BaseModel, Field

from ..auth import verify_token, verify_token_or_query
from ..config import MediaFolderConfig, settings
from ..config_manager import config_manager
from ..services import get_media_controller
from ..services.browser_service import BrowserService
from ..services.metadata_service import MetadataService
from ..services.thumbnail_service import ThumbnailService
from ..services.websocket_manager import ws_manager

logger = logging.getLogger(__name__)

router = APIRouter(prefix="/api/browser", tags=["browser"])

# Strong refs to background tasks so they don't get garbage-collected mid-flight.
_background_tasks: set[asyncio.Task] = set()


def _spawn_background(coro) -> asyncio.Task:
    """Schedule a background coroutine and keep a strong ref to its Task."""
    task = asyncio.create_task(coro)
    _background_tasks.add(task)
    task.add_done_callback(_background_tasks.discard)
    return task


def _require_folder_management() -> None:
    """Raise 403 if media folder management is disabled OR caller lacks admin scope."""
    if not settings.media_folders_management:
        raise HTTPException(
            status_code=403,
            detail="Media folder management is disabled. Set media_folders_management: true in config.yaml to enable.",
        )
    from ..auth import auth_enabled, token_has_scope, token_label_var
    if auth_enabled():
        label = token_label_var.get("unknown")
        if not token_has_scope(label, "admin"):
            raise HTTPException(
                status_code=403,
                detail=f"Token '{label}' lacks required scope: admin",
            )


async def _broadcast_after_open(controller, label: str, max_wait: float = 2.0) -> None:
    """Poll until media session registers, then broadcast status update.

    Fires as a background task so the HTTP response returns immediately.
    """
    status = None
    try:
        interval = 0.3
        elapsed = 0.0
        while elapsed < max_wait:
            await asyncio.sleep(interval)
            elapsed += interval
            try:
                status = await controller.get_status()
            except Exception as poll_err:  # noqa: BLE001 — broadcast is best-effort
                logger.debug("get_status during broadcast poll failed: %s", poll_err)
                continue
            if status.state in ("playing", "paused"):
                break

        if status is None:
            return
        status_dict = status.model_dump()
        await ws_manager.broadcast({"type": "status", "data": status_dict})
        logger.info(f"Broadcasted status update after opening: {label}")
    except Exception as e:
        logger.warning(f"Failed to broadcast status after opening {label}: {e}")


# Request/Response Models
class FolderCreateRequest(BaseModel):
    """Request model for creating a media folder."""

    folder_id: str = Field(..., description="Unique folder ID")
    label: str = Field(..., description="Display label")
    path: str = Field(..., description="Absolute path to media folder")
    enabled: bool = Field(default=True, description="Whether folder is enabled")


class FolderUpdateRequest(BaseModel):
    """Request model for updating a media folder."""

    label: str = Field(..., description="Display label")
    path: str = Field(..., description="Absolute path to media folder")
    enabled: bool = Field(default=True, description="Whether folder is enabled")


class PlayRequest(BaseModel):
    """Request model for playing a media file.

    Both ``folder_id`` and ``path`` are required so the server can validate
    the file lives inside a configured media folder.
    """

    folder_id: str = Field(..., description="Media folder ID")
    path: str = Field(..., description="Path relative to folder root")


class PlayFolderRequest(BaseModel):
    """Request model for playing all media files in a folder."""

    folder_id: str = Field(..., description="Media folder ID")
    path: str = Field(default="", description="Path relative to folder root")


# Folder Management Endpoints
@router.get("/folders")
async def list_folders(_: str = Depends(verify_token)):
    """List all configured media folders.

    Returns:
        Dictionary with folder configurations and management flag.
    """
    folders = {}
    for folder_id, config in settings.media_folders.items():
        folder_path = Path(config.path)
        folders[folder_id] = {
            "id": folder_id,
            "label": config.label,
            "path": config.path,
            "enabled": config.enabled,
            "available": folder_path.is_dir(),
        }
    return {
        "folders": folders,
        "management_enabled": settings.media_folders_management,
    }


@router.post("/folders/create")
async def create_folder(
    request: FolderCreateRequest,
    _: str = Depends(verify_token),
):
    """Create a new media folder configuration.

    Args:
        request: Folder creation request.

    Returns:
        Success message.

    Raises:
        HTTPException: If folder already exists or validation fails.
    """
    _require_folder_management()
    try:
        # Validate folder_id format (alphanumeric and underscore only).
        # Same constraint is enforced when validating paths so traversal can't
        # be smuggled through the ID itself.
        if not request.folder_id or not request.folder_id.replace("_", "").isalnum():
            raise HTTPException(
                status_code=400,
                detail="Folder ID must contain only alphanumeric characters and underscores",
            )

        # Validate path exists
        path = Path(request.path)
        if not path.exists():
            raise HTTPException(status_code=400, detail=f"Path does not exist: {request.path}")
        if not path.is_dir():
            raise HTTPException(status_code=400, detail=f"Path is not a directory: {request.path}")

        # Create config
        config = MediaFolderConfig(
            path=request.path,
            label=request.label,
            enabled=request.enabled,
        )

        # Add to config manager
        config_manager.add_media_folder(request.folder_id, config)

        return {
            "success": True,
            "message": f"Media folder '{request.folder_id}' created successfully",
        }

    except HTTPException:
        raise
    except ValueError as e:
        raise HTTPException(status_code=400, detail=str(e))
    except Exception as e:
        logger.error(f"Error creating media folder: {e}")
        raise HTTPException(status_code=500, detail="Failed to create media folder")


@router.put("/folders/update/{folder_id}")
async def update_folder(
    folder_id: str,
    request: FolderUpdateRequest,
    _: str = Depends(verify_token),
):
    """Update an existing media folder configuration.

    Args:
        folder_id: ID of the folder to update.
        request: Folder update request.

    Returns:
        Success message.

    Raises:
        HTTPException: If folder doesn't exist or validation fails.
    """
    _require_folder_management()
    try:
        # Validate path exists
        path = Path(request.path)
        if not path.exists():
            raise HTTPException(status_code=400, detail=f"Path does not exist: {request.path}")
        if not path.is_dir():
            raise HTTPException(status_code=400, detail=f"Path is not a directory: {request.path}")

        # Create config
        config = MediaFolderConfig(
            path=request.path,
            label=request.label,
            enabled=request.enabled,
        )

        # Update config manager
        config_manager.update_media_folder(folder_id, config)

        return {
            "success": True,
            "message": f"Media folder '{folder_id}' updated successfully",
        }

    except HTTPException:
        raise
    except ValueError as e:
        raise HTTPException(status_code=400, detail=str(e))
    except Exception as e:
        logger.error(f"Error updating media folder: {e}")
        raise HTTPException(status_code=500, detail="Failed to update media folder")


@router.delete("/folders/delete/{folder_id}")
async def delete_folder(
    folder_id: str,
    _: str = Depends(verify_token),
):
    """Delete a media folder configuration.

    Args:
        folder_id: ID of the folder to delete.

    Returns:
        Success message.

    Raises:
        HTTPException: If folder doesn't exist.
    """
    _require_folder_management()
    try:
        config_manager.delete_media_folder(folder_id)

        return {
            "success": True,
            "message": f"Media folder '{folder_id}' deleted successfully",
        }

    except ValueError as e:
        raise HTTPException(status_code=404, detail=str(e))
    except Exception as e:
        logger.error(f"Error deleting media folder: {e}")
        raise HTTPException(status_code=500, detail="Failed to delete media folder")


# Browse Endpoints
@router.get("/browse")
async def browse(
    folder_id: str = Query(..., description="Media folder ID"),
    path: str = Query(default="", description="Path relative to folder root"),
    offset: int = Query(default=0, ge=0, description="Pagination offset"),
    limit: int = Query(default=100, ge=1, le=1000, description="Pagination limit"),
    nocache: bool = Query(default=False, description="Bypass directory cache"),
    _: str = Depends(verify_token),
):
    """Browse a directory and list files/folders.

    Args:
        folder_id: ID of the media folder.
        path: Path to browse (URL-encoded, relative to folder root).
        offset: Pagination offset.
        limit: Maximum items to return.

    Returns:
        Directory listing with items and metadata.

    Raises:
        HTTPException: If path validation fails or directory not accessible.
    """
    try:
        # URL decode the path
        decoded_path = unquote(path)

        # Browse directory in a thread — iterdir() + stat() can block on
        # network shares for many seconds; never run on the event loop.
        result = await asyncio.to_thread(
            BrowserService.browse_directory,
            folder_id,
            decoded_path,
            offset,
            limit,
            nocache,
        )

        return result

    except ValueError as e:
        raise HTTPException(status_code=400, detail=str(e))
    except FileNotFoundError as e:
        raise HTTPException(status_code=404, detail=str(e))
    except (OSError, PermissionError) as e:
        # Network share unavailable or access denied
        logger.warning(f"Folder temporarily unavailable: {e}")
        raise HTTPException(
            status_code=503,
            detail="Folder is temporarily unavailable. It may be a network share that is not accessible at the moment."
        )
    except Exception as e:
        logger.error(f"Error browsing directory (type: {type(e).__name__}): {e}")
        raise HTTPException(status_code=500, detail="Failed to browse directory")


# Metadata Endpoint
@router.get("/metadata")
async def get_metadata(
    folder_id: str = Query(..., description="Media folder ID"),
    path: str = Query(..., description="Path relative to folder root (URL-encoded)"),
    _: str = Depends(verify_token),
):
    """Get metadata for a media file inside a configured media folder.

    Args:
        folder_id: ID of the media folder.
        path: Path relative to folder root (URL-encoded).

    Returns:
        Media file metadata.
    """
    try:
        decoded_path = unquote(path)
        file_path = BrowserService.validate_path(folder_id, decoded_path)

        if not file_path.is_file():
            raise HTTPException(status_code=400, detail="Path is not a file")
        if not BrowserService.is_media_file(file_path):
            raise HTTPException(status_code=400, detail="File is not a media file")

        loop = asyncio.get_running_loop()
        metadata = await loop.run_in_executor(
            None,
            MetadataService.extract_metadata,
            file_path,
        )
        return metadata

    except ValueError as e:
        raise HTTPException(status_code=400, detail=str(e))
    except FileNotFoundError as e:
        raise HTTPException(status_code=404, detail=str(e))
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"Error extracting metadata: {e}")
        raise HTTPException(status_code=500, detail="Failed to extract metadata")


# Thumbnail Endpoint
@router.get("/thumbnail")
async def get_thumbnail(
    folder_id: str = Query(..., description="Media folder ID"),
    path: str = Query(..., description="Path relative to folder root (URL-encoded)"),
    size: str = Query(default="medium", description='Thumbnail size: "small" or "medium"'),
    _: str = Depends(verify_token),
):
    """Get thumbnail for a media file inside a configured media folder."""
    try:
        decoded_path = unquote(path)
        file_path = BrowserService.validate_path(folder_id, decoded_path)

        if not file_path.is_file():
            raise HTTPException(status_code=400, detail="Path is not a file")
        if not BrowserService.is_media_file(file_path):
            raise HTTPException(status_code=400, detail="File is not a media file")

        if size not in ("small", "medium"):
            size = "medium"

        thumbnail_data = await ThumbnailService.get_thumbnail(file_path, size)

        if thumbnail_data is None:
            return Response(status_code=204)

        import hashlib
        stat = file_path.stat()
        etag_data = f"{file_path}:{stat.st_mtime}:{size}".encode()
        etag = hashlib.md5(etag_data).hexdigest()

        return Response(
            content=thumbnail_data,
            media_type="image/jpeg",
            headers={
                "ETag": f'"{etag}"',
                "Cache-Control": "public, max-age=86400",
            },
        )

    except ValueError as e:
        raise HTTPException(status_code=400, detail=str(e))
    except FileNotFoundError as e:
        raise HTTPException(status_code=404, detail=str(e))
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"Error generating thumbnail: {e}")
        raise HTTPException(status_code=500, detail="Failed to generate thumbnail")


# Playback Endpoint
@router.post("/play")
async def play_file(
    request: PlayRequest,
    _: str = Depends(verify_token),
):
    """Open a media file with the default system player.

    Requires both ``folder_id`` and a folder-relative ``path``; the resolved
    file must live inside the configured media folder and be a recognized
    media file. This prevents arbitrary OS-handler invocation (e.g.,
    ``os.startfile`` on Windows ``.lnk``/UNC paths).
    """
    try:
        decoded_path = unquote(request.path)
        file_path = BrowserService.validate_path(request.folder_id, decoded_path)

        if not file_path.is_file():
            raise HTTPException(status_code=400, detail="Path is not a file")
        if not BrowserService.is_media_file(file_path):
            raise HTTPException(status_code=400, detail="File is not a media file")

        controller = get_media_controller()
        success = await controller.open_file(str(file_path))

        if not success:
            raise HTTPException(status_code=500, detail="Failed to open file")

        _spawn_background(_broadcast_after_open(controller, file_path.name))

        return {
            "success": True,
            "message": f"Playing {file_path.name}",
        }

    except ValueError as e:
        raise HTTPException(status_code=400, detail=str(e))
    except FileNotFoundError as e:
        raise HTTPException(status_code=404, detail=str(e))
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"Error playing file: {e}")
        raise HTTPException(status_code=500, detail="Failed to play file")


# Play Folder Endpoint (M3U playlist)
@router.post("/play-folder")
async def play_folder(
    request: PlayFolderRequest,
    _: str = Depends(verify_token),
):
    """Play all media files in a folder by generating an M3U playlist.

    Args:
        request: Play folder request with folder_id and path.

    Returns:
        Success message with file count.

    Raises:
        HTTPException: If folder not found or playback fails.
    """
    try:
        decoded_path = unquote(request.path)
        full_path = BrowserService.validate_path(request.folder_id, decoded_path)

        if not full_path.is_dir():
            raise HTTPException(status_code=400, detail="Path is not a directory")

        def _scan(directory: Path) -> list[Path]:
            return sorted(
                (
                    f for f in directory.iterdir()
                    if f.is_file() and BrowserService.is_media_file(f)
                ),
                key=lambda f: f.name.lower(),
            )

        media_files = await asyncio.to_thread(_scan, full_path)

        if not media_files:
            raise HTTPException(status_code=404, detail="No media files found in this folder")

        # Generate M3U playlist with absolute paths and EXTINF entries.
        # Use NamedTemporaryFile to get a fresh per-call path — prevents
        # symlink-clobber races between concurrent /play-folder requests
        # and any local user pre-creating a fixed temp filename.
        lines = ["#EXTM3U"]
        for f in media_files:
            lines.append(f"#EXTINF:-1,{f.stem}")
            lines.append(str(f))
        m3u_content = ("\r\n".join(lines) + "\r\n").encode("utf-8-sig")

        with tempfile.NamedTemporaryFile(
            mode="wb",
            prefix=".media_server_playlist_",
            suffix=".m3u",
            delete=False,
        ) as f:
            f.write(m3u_content)
            playlist_path = Path(f.name)

        # Open playlist with default player
        controller = get_media_controller()
        success = await controller.open_file(playlist_path)

        if not success:
            raise HTTPException(status_code=500, detail="Failed to open playlist")

        _spawn_background(
            _broadcast_after_open(controller, f"playlist ({len(media_files)} files)")
        )

        return {
            "success": True,
            "message": f"Playing {len(media_files)} files",
            "count": len(media_files),
        }

    except HTTPException:
        raise
    except ValueError as e:
        raise HTTPException(status_code=400, detail=str(e))
    except FileNotFoundError as e:
        raise HTTPException(status_code=404, detail=str(e))
    except Exception as e:
        logger.error(f"Error playing folder: {e}")
        raise HTTPException(status_code=500, detail="Failed to play folder")


# Download Endpoint
@router.get("/download")
async def download_file(
    folder_id: str = Query(..., description="Media folder ID"),
    path: str = Query(..., description="File path relative to folder root (URL-encoded)"),
    _: str = Depends(verify_token_or_query),
):
    """Download a media file.

    Args:
        folder_id: ID of the media folder.
        path: Path to the file (URL-encoded, relative to folder root).

    Returns:
        File download response.

    Raises:
        HTTPException: If file not found or not a media file.
    """
    try:
        decoded_path = unquote(path)
        file_path = BrowserService.validate_path(folder_id, decoded_path)

        if not file_path.is_file():
            raise HTTPException(status_code=400, detail="Path is not a file")

        if not BrowserService.is_media_file(file_path):
            raise HTTPException(status_code=400, detail="File is not a media file")

        return FileResponse(
            path=file_path,
            filename=file_path.name,
            media_type="application/octet-stream",
        )

    except ValueError as e:
        raise HTTPException(status_code=400, detail=str(e))
    except FileNotFoundError as e:
        raise HTTPException(status_code=404, detail=str(e))
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"Error downloading file: {e}")
        raise HTTPException(status_code=500, detail="Failed to download file")