from fastapi import FastAPI, Request, Depends, Form, Response, HTTPException, status
from fastapi.templating import Jinja2Templates
from fastapi.staticfiles import StaticFiles
from fastapi.responses import HTMLResponse, JSONResponse, RedirectResponse, StreamingResponse
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select, func
from contextlib import asynccontextmanager
import json
from datetime import datetime
from typing import Optional
import httpx
import os
from pathlib import Path

from app.database import init_db, get_db
from app.models import Book, ListeningSession, Recommendation, User, AppSettings
from app.abs_client import get_abs_client
from app.recommender import BookRecommender
from app.config import get_settings
from app.auth import (
    get_current_user,
    get_current_user_optional,
    get_current_admin,
    authenticate_user,
    create_user,
    set_session_cookie,
    clear_session_cookie
)
from app.services.stats import ReadingStatsService


def extract_author_name(metadata: dict) -> str:
    """
    Extract author name from Audiobookshelf metadata.

    Tries multiple fields in order:
    1. authorName (string field)
    2. authors array (extract first author's name)
    3. Falls back to "Unknown"
    """
    # Try authorName field first
    author_name = metadata.get("authorName")
    if author_name:
        return author_name

    # Try authors array
    authors = metadata.get("authors", [])
    if authors and len(authors) > 0:
        # Authors can be objects with 'name' field or just strings
        first_author = authors[0]
        if isinstance(first_author, dict):
            author_name = first_author.get("name")
            if author_name:
                return author_name
        elif isinstance(first_author, str):
            return first_author

    return "Unknown"


@asynccontextmanager
async def lifespan(app: FastAPI):
    """Initialize database on startup."""
    await init_db()
    yield


# Initialize FastAPI app
app = FastAPI(
    title="Dewy Oracle",
    description="AI-powered book recommendations based on your listening history",
    lifespan=lifespan
)

# Setup templates and static files
templates = Jinja2Templates(directory="app/templates")
app.mount("/static", StaticFiles(directory="app/static"), name="static")

# Initialize recommender (shared across users)
recommender = BookRecommender()


@app.get("/", response_class=HTMLResponse)
async def home(
    request: Request,
    db: AsyncSession = Depends(get_db),
    user: Optional[User] = Depends(get_current_user_optional)
):
    """Home page showing dashboard or landing page."""
    # If user not logged in, show landing page
    if not user:
        return templates.TemplateResponse(
            "index.html",
            {
                "request": request,
                "user": None,
                "books": [],
                "recommendations": []
            }
        )

    # Get user's recent books and recommendations
    recent_sessions = await db.execute(
        select(ListeningSession)
        .where(ListeningSession.user_id == user.id)
        .order_by(ListeningSession.last_update.desc())
        .limit(10)
    )
    sessions = recent_sessions.scalars().all()

    # Get book details for sessions
    books = []
    for session in sessions:
        book_result = await db.execute(
            select(Book).where(Book.id == session.book_id)
        )
        book = book_result.scalar_one_or_none()
        if book:
            books.append({
                "book": book,
                "session": session
            })

    # Get user's recent recommendations
    recs_result = await db.execute(
        select(Recommendation)
        .where(
            Recommendation.user_id == user.id,
            Recommendation.dismissed == False
        )
        .order_by(Recommendation.created_at.desc())
        .limit(5)
    )
    recommendations_raw = recs_result.scalars().all()

    # Parse JSON fields for template
    recommendations = []
    for rec in recommendations_raw:
        rec_dict = {
            "id": rec.id,
            "title": rec.title,
            "author": rec.author,
            "description": rec.description,
            "reason": rec.reason,
            "genres": json.loads(rec.genres) if rec.genres else []
        }
        recommendations.append(rec_dict)

    return templates.TemplateResponse(
        "index.html",
        {
            "request": request,
            "user": user,
            "books": books,
            "recommendations": recommendations
        }
    )


# ==================== Authentication Routes ====================


@app.get("/login", response_class=HTMLResponse)
async def login_page(request: Request):
    """Login page."""
    return templates.TemplateResponse("login.html", {"request": request})


@app.post("/api/auth/login")
async def login(
    username: str = Form(...),
    password: str = Form(...),
    db: AsyncSession = Depends(get_db)
):
    """Authenticate user and create session."""
    user = await authenticate_user(db, username, password)

    if not user:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Incorrect username or password"
        )

    # Create redirect response and set session cookie
    redirect = RedirectResponse(url="/", status_code=status.HTTP_303_SEE_OTHER)
    set_session_cookie(redirect, user.id)

    return redirect


@app.get("/register", response_class=HTMLResponse)
async def register_page(request: Request):
    """Registration page."""
    return templates.TemplateResponse("register.html", {"request": request})


@app.post("/api/auth/register")
async def register(
    username: str = Form(...),
    email: str = Form(...),
    password: str = Form(...),
    abs_url: str = Form(...),
    abs_api_token: str = Form(...),
    display_name: Optional[str] = Form(None),
    db: AsyncSession = Depends(get_db)
):
    """Register a new user."""
    try:
        # Check if registration is allowed
        result = await db.execute(
            select(AppSettings).where(AppSettings.key == "allow_registration")
        )
        allow_reg_setting = result.scalar_one_or_none()

        # Check if there are any existing users (first user is always allowed)
        result = await db.execute(select(func.count(User.id)))
        user_count = result.scalar()

        if user_count > 0 and allow_reg_setting and allow_reg_setting.value.lower() != 'true':
            raise HTTPException(
                status_code=status.HTTP_403_FORBIDDEN,
                detail="Registration is currently disabled"
            )

        user = await create_user(
            db=db,
            username=username,
            email=email,
            password=password,
            abs_url=abs_url,
            abs_api_token=abs_api_token,
            display_name=display_name
        )

        # Create redirect response and set session cookie
        redirect = RedirectResponse(url="/", status_code=status.HTTP_303_SEE_OTHER)
        set_session_cookie(redirect, user.id)

        return redirect

    except HTTPException as e:
        raise e
    except Exception as e:
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=str(e)
        )


@app.post("/api/auth/logout")
async def logout(response: Response):
    """Logout user and clear session."""
    clear_session_cookie(response)
    return JSONResponse({
        "status": "success",
        "message": "Logged out successfully"
    })


# ==================== API Routes ====================


async def download_cover_image(abs_client, book_id: str) -> Optional[str]:
    """
    Download cover image from Audiobookshelf and save locally.

    Args:
        abs_client: Audiobookshelf client with authentication
        book_id: Library item ID

    Returns:
        Local path to saved cover (e.g., /static/covers/book_id.jpg) or None
    """
    if not book_id:
        return None

    # Create covers directory if it doesn't exist
    covers_dir = Path("app/static/covers")
    covers_dir.mkdir(parents=True, exist_ok=True)

    # Use Audiobookshelf API cover endpoint
    cover_url = f"{abs_client.base_url}/api/items/{book_id}/cover"

    async with httpx.AsyncClient() as client:
        try:
            response = await client.get(cover_url, headers=abs_client.headers, follow_redirects=True)
            response.raise_for_status()

            # Determine extension from content-type
            content_type = response.headers.get("content-type", "image/jpeg")
            ext = ".webp" if "webp" in content_type else ".jpg"
            local_filename = f"{book_id}{ext}"
            local_path = covers_dir / local_filename

            # Save to local file
            with open(local_path, "wb") as f:
                f.write(response.content)

            # Return path relative to static directory
            return f"/static/covers/{local_filename}"
        except Exception as e:
            print(f"Failed to download cover for {book_id}: {e}")
            return None


@app.get("/api/sync")
async def sync_with_audiobookshelf(
    db: AsyncSession = Depends(get_db),
    user: User = Depends(get_current_user)
):
    """Sync library and progress from Audiobookshelf."""
    try:
        # Create user-specific ABS client
        abs_client = get_abs_client(user)

        # Get user info which includes all media progress
        user_info = await abs_client.get_user_info()
        media_progress = user_info.get("mediaProgress", [])

        synced_count = 0
        for progress_item in media_progress:
            # Skip podcast episodes, only process books
            if progress_item.get("mediaItemType") != "book":
                continue

            library_item_id = progress_item.get("libraryItemId")
            if not library_item_id:
                continue

            # Fetch full library item details
            try:
                item = await abs_client.get_item_details(library_item_id)
            except:
                # Skip if item not found
                continue
            # Extract book info
            media = item.get("media", {})
            metadata = media.get("metadata", {})

            book_id = item.get("id")
            if not book_id:
                continue

            # Check if book exists in DB
            result = await db.execute(select(Book).where(Book.id == book_id))
            book = result.scalar_one_or_none()

            # Download cover image and get local path
            local_cover_url = await download_cover_image(abs_client, book_id)

            # Create or update book
            if not book:
                book = Book(
                    id=book_id,
                    title=metadata.get("title", "Unknown"),
                    author=extract_author_name(metadata),
                    narrator=metadata.get("narratorName"),
                    description=metadata.get("description"),
                    genres=json.dumps(metadata.get("genres", [])),
                    tags=json.dumps(media.get("tags", [])),
                    duration=media.get("duration", 0),
                    cover_url=local_cover_url  # Store local path
                )
                db.add(book)
            else:
                # Update existing book
                book.title = metadata.get("title", book.title)
                book.author = extract_author_name(metadata)
                if local_cover_url:  # Only update if download succeeded
                    book.cover_url = local_cover_url
                book.updated_at = datetime.now()

            # Update or create listening session
            progress_data = progress_item.get("progress", 0)
            current_time = progress_item.get("currentTime", 0)
            is_finished = progress_item.get("isFinished", False)
            started_at_ts = progress_item.get("startedAt")
            finished_at_ts = progress_item.get("finishedAt")

            session_result = await db.execute(
                select(ListeningSession)
                .where(
                    ListeningSession.user_id == user.id,
                    ListeningSession.book_id == book_id
                )
                .order_by(ListeningSession.last_update.desc())
                .limit(1)
            )
            session = session_result.scalar_one_or_none()

            if not session:
                session = ListeningSession(
                    user_id=user.id,
                    book_id=book_id,
                    progress=progress_data,
                    current_time=current_time,
                    is_finished=is_finished,
                    started_at=datetime.fromtimestamp(started_at_ts / 1000) if started_at_ts else datetime.now(),
                    finished_at=datetime.fromtimestamp(finished_at_ts / 1000) if finished_at_ts else None
                )
                db.add(session)
            else:
                # Update existing session
                session.progress = progress_data
                session.current_time = current_time
                session.is_finished = is_finished
                if finished_at_ts and not session.finished_at:
                    session.finished_at = datetime.fromtimestamp(finished_at_ts / 1000)

            synced_count += 1

        await db.commit()

        return JSONResponse({
            "status": "success",
            "synced": synced_count,
            "message": f"Synced {synced_count} books from Audiobookshelf"
        })

    except Exception as e:
        return JSONResponse(
            {"status": "error", "message": str(e)},
            status_code=500
        )


@app.get("/api/recommendations/generate")
async def generate_recommendations(
    db: AsyncSession = Depends(get_db),
    user: User = Depends(get_current_user)
):
    """Generate new AI recommendations based on reading history."""
    try:
        # Get finished books for context
        finished_result = await db.execute(
            select(ListeningSession, Book)
            .join(Book, ListeningSession.book_id == Book.id)
            .where(
                ListeningSession.user_id == user.id,
                ListeningSession.is_finished == True
            )
            .order_by(ListeningSession.finished_at.desc())
            .limit(20)
        )
        finished_items = finished_result.all()

        if not finished_items:
            return JSONResponse({
                "status": "error",
                "message": "No reading history found. Please sync with Audiobookshelf first."
            })

        # Format reading history
        reading_history = []
        for session, book in finished_items:
            reading_history.append({
                "title": book.title,
                "author": book.author,
                "genres": json.loads(book.genres) if book.genres else [],
                "progress": session.progress,
                "is_finished": session.is_finished
            })

        # Generate recommendations
        new_recs = await recommender.generate_recommendations(
            reading_history, num_recommendations=5
        )

        # Save to database
        for rec in new_recs:
            recommendation = Recommendation(
                user_id=user.id,
                title=rec.get("title"),
                author=rec.get("author"),
                description=rec.get("description"),
                reason=rec.get("reason"),
                genres=json.dumps(rec.get("genres", []))
            )
            db.add(recommendation)

        await db.commit()

        return JSONResponse({
            "status": "success",
            "recommendations": new_recs,
            "count": len(new_recs)
        })

    except Exception as e:
        return JSONResponse(
            {"status": "error", "message": str(e)},
            status_code=500
        )


@app.get("/api/recommendations")
async def get_recommendations(
    db: AsyncSession = Depends(get_db),
    user: User = Depends(get_current_user)
):
    """Get saved recommendations."""
    result = await db.execute(
        select(Recommendation)
        .where(
            Recommendation.user_id == user.id,
            Recommendation.dismissed == False
        )
        .order_by(Recommendation.created_at.desc())
    )
    recommendations = result.scalars().all()

    return JSONResponse({
        "recommendations": [
            {
                "id": rec.id,
                "title": rec.title,
                "author": rec.author,
                "description": rec.description,
                "reason": rec.reason,
                "genres": json.loads(rec.genres) if rec.genres else [],
                "created_at": rec.created_at.isoformat()
            }
            for rec in recommendations
        ]
    })


@app.get("/api/history")
async def get_listening_history(
    db: AsyncSession = Depends(get_db),
    user: User = Depends(get_current_user)
):
    """Get listening history."""
    result = await db.execute(
        select(ListeningSession, Book)
        .join(Book, ListeningSession.book_id == Book.id)
        .where(ListeningSession.user_id == user.id)
        .order_by(ListeningSession.last_update.desc())
    )
    items = result.all()

    return JSONResponse({
        "history": [
            {
                "book": {
                    "id": book.id,
                    "title": book.title,
                    "author": book.author,
                    "cover_url": book.cover_url,
                },
                "session": {
                    "progress": session.progress,
                    "is_finished": session.is_finished,
                    "started_at": session.started_at.isoformat() if session.started_at else None,
                    "finished_at": session.finished_at.isoformat() if session.finished_at else None,
                }
            }
            for session, book in items
        ]
    })


# ==================== Reading Log Routes ====================


@app.get("/reading-log", response_class=HTMLResponse)
async def reading_log_page(
    request: Request,
    user: User = Depends(get_current_user)
):
    """Reading log page with stats and filters."""
    return templates.TemplateResponse(
        "reading_log.html",
        {
            "request": request,
            "user": user
        }
    )


@app.get("/api/reading-log/stats")
async def get_reading_stats(
    db: AsyncSession = Depends(get_db),
    user: User = Depends(get_current_user),
    start_date: Optional[str] = None,
    end_date: Optional[str] = None
):
    """Get reading statistics for the user."""
    try:
        # Parse dates if provided
        start_dt = datetime.fromisoformat(start_date) if start_date else None
        end_dt = datetime.fromisoformat(end_date) if end_date else None

        # Calculate stats
        stats_service = ReadingStatsService(db, user.id, user.abs_url)
        stats = await stats_service.calculate_stats(start_dt, end_dt)

        return JSONResponse(stats)

    except Exception as e:
        return JSONResponse(
            {"status": "error", "message": str(e)},
            status_code=500
        )


@app.put("/api/sessions/{session_id}/rating")
async def update_session_rating(
    session_id: int,
    rating: int = Form(...),
    db: AsyncSession = Depends(get_db),
    user: User = Depends(get_current_user)
):
    """Update the rating for a listening session."""
    try:
        # Validate rating
        if rating < 1 or rating > 5:
            raise HTTPException(
                status_code=status.HTTP_400_BAD_REQUEST,
                detail="Rating must be between 1 and 5"
            )

        # Get session and verify ownership
        result = await db.execute(
            select(ListeningSession).where(
                ListeningSession.id == session_id,
                ListeningSession.user_id == user.id
            )
        )
        session = result.scalar_one_or_none()

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

        # Update rating
        session.rating = rating
        await db.commit()

        return JSONResponse({
            "status": "success",
            "message": "Rating updated successfully",
            "rating": rating
        })

    except HTTPException as e:
        raise e
    except Exception as e:
        return JSONResponse(
            {"status": "error", "message": str(e)},
            status_code=500
        )


# ==================== Admin Routes ====================


@app.get("/admin", response_class=HTMLResponse)
async def admin_page(
    request: Request,
    user: User = Depends(get_current_admin)
):
    """Admin panel page."""
    return templates.TemplateResponse(
        "admin.html",
        {
            "request": request,
            "user": user
        }
    )


@app.get("/api/admin/settings")
async def get_admin_settings(
    db: AsyncSession = Depends(get_db),
    admin: User = Depends(get_current_admin)
):
    """Get application settings."""
    result = await db.execute(select(AppSettings))
    settings = result.scalars().all()

    settings_dict = {s.key: s.value for s in settings}

    return JSONResponse(settings_dict)


@app.put("/api/admin/settings/{key}")
async def update_setting(
    key: str,
    value: str = Form(...),
    db: AsyncSession = Depends(get_db),
    admin: User = Depends(get_current_admin)
):
    """Update an application setting."""
    result = await db.execute(
        select(AppSettings).where(AppSettings.key == key)
    )
    setting = result.scalar_one_or_none()

    if not setting:
        # Create new setting
        setting = AppSettings(key=key, value=value)
        db.add(setting)
    else:
        # Update existing
        setting.value = value

    await db.commit()

    return JSONResponse({
        "status": "success",
        "message": f"Setting {key} updated"
    })


@app.get("/api/admin/users")
async def get_users(
    db: AsyncSession = Depends(get_db),
    admin: User = Depends(get_current_admin)
):
    """Get all users."""
    result = await db.execute(select(User).order_by(User.created_at.desc()))
    users = result.scalars().all()

    users_list = [
        {
            "id": user.id,
            "username": user.username,
            "email": user.email,
            "display_name": user.display_name,
            "is_admin": user.is_admin,
            "is_active": user.is_active,
            "created_at": user.created_at.isoformat() if user.created_at else None,
            "last_login": user.last_login.isoformat() if user.last_login else None,
            "is_current": user.id == admin.id
        }
        for user in users
    ]

    return JSONResponse({"users": users_list})


@app.put("/api/admin/users/{user_id}/admin")
async def toggle_user_admin(
    user_id: int,
    is_admin: str = Form(...),
    db: AsyncSession = Depends(get_db),
    admin: User = Depends(get_current_admin)
):
    """Toggle admin status for a user."""
    # Prevent admin from removing their own admin status
    if user_id == admin.id:
        return JSONResponse(
            {"status": "error", "message": "Cannot modify your own admin status"},
            status_code=400
        )

    result = await db.execute(select(User).where(User.id == user_id))
    user = result.scalar_one_or_none()

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

    user.is_admin = is_admin.lower() == 'true'
    await db.commit()

    return JSONResponse({
        "status": "success",
        "message": "User admin status updated"
    })


@app.delete("/api/admin/users/{user_id}")
async def delete_user(
    user_id: int,
    db: AsyncSession = Depends(get_db),
    admin: User = Depends(get_current_admin)
):
    """Delete a user."""
    # Prevent admin from deleting themselves
    if user_id == admin.id:
        return JSONResponse(
            {"status": "error", "message": "Cannot delete your own account"},
            status_code=400
        )

    result = await db.execute(select(User).where(User.id == user_id))
    user = result.scalar_one_or_none()

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

    await db.delete(user)
    await db.commit()

    return JSONResponse({
        "status": "success",
        "message": "User deleted successfully"
    })


@app.post("/api/admin/users")
async def create_user_by_admin(
    username: str = Form(...),
    email: str = Form(...),
    password: str = Form(...),
    display_name: str = Form(None),
    abs_url: str = Form(...),
    abs_api_token: str = Form(...),
    is_admin: str = Form("false"),
    db: AsyncSession = Depends(get_db),
    admin: User = Depends(get_current_admin)
):
    """Create a new user (admin only)."""
    try:
        # Check if username exists
        result = await db.execute(select(User).where(User.username == username))
        if result.scalar_one_or_none():
            return JSONResponse(
                {"status": "error", "message": "Username already exists"},
                status_code=400
            )

        # Check if email exists
        result = await db.execute(select(User).where(User.email == email))
        if result.scalar_one_or_none():
            return JSONResponse(
                {"status": "error", "message": "Email already exists"},
                status_code=400
            )

        # Create new user
        new_user = await create_user(
            db=db,
            username=username,
            email=email,
            password=password,
            display_name=display_name,
            abs_url=abs_url,
            abs_api_token=abs_api_token
        )

        # Set admin status if requested
        if is_admin.lower() == "true":
            new_user.is_admin = True
            await db.commit()

        return JSONResponse({
            "status": "success",
            "message": f"User '{username}' created successfully"
        })

    except Exception as e:
        return JSONResponse(
            {"status": "error", "message": str(e)},
            status_code=500
        )


@app.put("/api/admin/users/{user_id}/password")
async def change_user_password(
    user_id: int,
    new_password: str = Form(...),
    db: AsyncSession = Depends(get_db),
    admin: User = Depends(get_current_admin)
):
    """Change a user's password (admin only)."""
    try:
        # Validate password length
        if len(new_password) < 6:
            return JSONResponse(
                {"status": "error", "message": "Password must be at least 6 characters"},
                status_code=400
            )

        # Get user
        result = await db.execute(select(User).where(User.id == user_id))
        user = result.scalar_one_or_none()

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

        # Update password
        from app.auth import hash_password
        user.hashed_password = hash_password(new_password)
        await db.commit()

        return JSONResponse({
            "status": "success",
            "message": f"Password changed for user '{user.username}'"
        })

    except HTTPException:
        raise
    except Exception as e:
        return JSONResponse(
            {"status": "error", "message": str(e)},
            status_code=500
        )


@app.get("/health")
async def health_check():
    """Health check endpoint."""
    return {"status": "healthy"}