from datetime import date
from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import text
from app.database import get_db

router = APIRouter(prefix="/books", tags=["Books"])


@router.get("/")
async def get_all_books(db: AsyncSession = Depends(get_db)):
    result = await db.execute(text("""
        SELECT b.id, b.title, b.genre, b.published, a.name AS author
        FROM books b
        JOIN authors a ON a.id = b.author_id
        ORDER BY b.title
    """))
    return result.mappings().all()


@router.get("/{book_id}")
async def get_book(book_id: int, db: AsyncSession = Depends(get_db)):
    result = await db.execute(
        text("""
            SELECT b.*, a.name AS author_name
            FROM books b
            JOIN authors a ON a.id = b.author_id
            WHERE b.id = :id
        """),
        {"id": book_id}
    )
    book = result.mappings().one_or_none()
    if not book:
        raise HTTPException(status_code=404, detail="Book not found")
    return book


@router.post("/", status_code=201)
async def create_book(
    title: str, author_id: int, genre: str = None,
    published: date = None, description: str = None,
    db: AsyncSession = Depends(get_db)
):
    # Check author exists
    result = await db.execute(
        text("SELECT id FROM authors WHERE id = :id"), {"id": author_id}
    )
    if not result.one_or_none():
        raise HTTPException(status_code=404, detail="Author not found")

    await db.execute(
        text("""
            INSERT INTO books (title, author_id, genre, published, description)
            VALUES (:title, :author_id, :genre, :published, :description)
        """),
        {"title": title, "author_id": author_id, "genre": genre,
         "published": published, "description": description}
    )
    await db.commit()
    return {"message": f"Book '{title}' created"}


@router.put("/{book_id}")
async def update_book(
    book_id: int, title: str = None, genre: str = None,
    description: str = None, db: AsyncSession = Depends(get_db)
):
    result = await db.execute(
        text("SELECT id FROM books WHERE id = :id"), {"id": book_id}
    )
    if not result.one_or_none():
        raise HTTPException(status_code=404, detail="Book not found")

    await db.execute(
        text("""
            UPDATE books
            SET title       = COALESCE(:title, title),
                genre       = COALESCE(:genre, genre),
                description = COALESCE(:description, description)
            WHERE id = :id
        """),
        {"id": book_id, "title": title, "genre": genre, "description": description}
    )
    await db.commit()
    return {"message": "Book updated"}


@router.delete("/{book_id}", status_code=204)
async def delete_book(book_id: int, db: AsyncSession = Depends(get_db)):
    result = await db.execute(
        text("SELECT id FROM books WHERE id = :id"), {"id": book_id}
    )
    if not result.one_or_none():
        raise HTTPException(status_code=404, detail="Book not found")

    await db.execute(
        text("DELETE FROM books WHERE id = :id"), {"id": book_id}
    )
    await db.commit()