from sqlalchemy import select, delete
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy.orm import selectinload

from models.library import LibraryFile, LibraryFileQuestion
from schemas.library import LibraryFileRequest, LibraryFileResponse, QuestionResponse


async def list_files(db: AsyncSession) -> list[LibraryFileResponse]:
    stmt = select(LibraryFile).order_by(LibraryFile.create_time.desc())
    files = (await db.execute(stmt)).scalars().all()

    return [
        LibraryFileResponse(
            id=file.id,
            subject=file.subject,
            module=file.module,
            name=file.name,
            type=file.type,
            size=file.size,
            content=file.content,
            uploadTime=file.create_time.strftime("%Y-%m-%d %H:%M:%S"),
            questions=[],
        )
        for file in files
    ]


async def add_file(db: AsyncSession, data: LibraryFileRequest) -> bool:
    """
    创建题库文件及其题目
    """
    file = LibraryFile(
        subject=data.subject,
        module=data.module,
        name=data.name,
        size=data.size,
        type=data.type,
        content=data.content,
    )

    db.add(file)
    await db.flush()

    for q in data.questions:
        question = LibraryFileQuestion(
            library_file_id=file.id,
            type=q.type,
            question=q.question,
            options=q.options,
            answer=q.answer
        )
        db.add(question)

    await db.commit()

    return True


async def edit_file(db: AsyncSession, file_id: int, data: LibraryFileRequest) -> bool:
    """
    编辑题库文件及其题目
    """

    result = await db.execute(
        select(LibraryFile).where(LibraryFile.id == file_id)
    )
    file = result.scalar_one_or_none()
    if not file:
        return False

    file.subject = data.subject
    file.module = data.module
    file.name = data.name
    file.size = data.size
    file.type = data.type
    file.content = data.content

    await db.execute(
        delete(LibraryFileQuestion)
        .where(LibraryFileQuestion.library_file_id == file.id)
    )

    # 4. 插入新题目
    for q in data.questions:
        question = LibraryFileQuestion(
            library_file_id=file.id,
            type=q.type,
            question=q.question,
            options=q.options,
            answer=q.answer,
        )
        db.add(question)

    await db.commit()

    return True


async def get_file(db: AsyncSession, file_id: int) -> LibraryFileResponse:
    stmt = (
        select(LibraryFile)
        .options(selectinload(LibraryFile.questions))
        .where(LibraryFile.id == file_id)
    )
    result = await db.execute(stmt)
    file = result.scalar_one_or_none()

    return LibraryFileResponse(
        id=file.id,
        subject=file.subject,
        module=file.module,
        name=file.name,
        type=file.type,
        size=file.size,
        content=file.content,
        uploadTime=file.create_time.strftime("%Y-%m-%d %H:%M:%S"),
        questions=[
            QuestionResponse(
                id=q.id,
                type=q.type,
                question=q.question,
                options=q.options,
                answer=q.answer
            )
            for q in file.questions
        ],
    )