"""
Files API Router
"""
import os
import asyncio
from pathlib import Path
from typing import Optional
from uuid import UUID, uuid4
from fastapi import APIRouter, Depends, UploadFile, File, Query
from fastapi.responses import FileResponse, PlainTextResponse
from sqlalchemy.ext.asyncio import AsyncSession

from app.api.response import ApiResponse, PaginatedResponse
from app.core.config import get_settings
from app.core.database import get_db
from app.core.exceptions import ValidationException, NotFoundException
from app.core.crud import CRUDBase
from app.core.logging import log_success, log_failure
from app.models.models import File as FileModel
from app.schemas.file import FileResponse, FileCreateSchema
from markitdown import MarkItDown

settings = get_settings()
router = APIRouter()

# Initialize CRUD
file_crud = CRUDBase(FileModel)

# Initialize markitdown
markitdown = MarkItDown()


def get_project_raw_dir(project_id: str) -> Path:
    """获取项目的 raw 文件目录"""
    base_dir = Path("/data/code/YG-Datasets/data") / project_id / "raw"
    base_dir.mkdir(parents=True, exist_ok=True)
    return base_dir


def get_project_ready_dir(project_id: str) -> Path:
    """获取项目的 ready 文件目录（处理后的文件）"""
    base_dir = Path("/data/code/YG-Datasets/data") / project_id / "ready"
    base_dir.mkdir(parents=True, exist_ok=True)
    return base_dir


def get_file_type(filename: str) -> str:
    """Get file type from extension"""
    ext = filename.rsplit('.', 1)[-1].lower() if '.' in filename else ''
    type_map = {
        'pdf': 'pdf',
        'docx': 'docx',
        'doc': 'docx',
        'xlsx': 'xlsx',
        'xls': 'xlsx',
        'csv': 'csv',
        'epub': 'epub',
        'md': 'md',
        'markdown': 'md',
        'txt': 'txt'
    }
    return type_map.get(ext, 'txt')


# Allowed file extensions
ALLOWED_EXTENSIONS = {'pdf', 'docx', 'doc', 'xlsx', 'xls', 'csv', 'epub', 'md', 'txt'}


def validate_file(filename: str, file_size: int) -> None:
    """Validate file extension and size"""
    ext = filename.rsplit('.', 1)[-1].lower() if '.' in filename else ''

    if ext not in ALLOWED_EXTENSIONS:
        raise ValidationException(
            f"File type '{ext}' not allowed",
            field="file"
        )

    if file_size > settings.MAX_FILE_SIZE:
        raise ValidationException(
            f"File size exceeds maximum allowed size of {settings.MAX_FILE_SIZE // (1024*1024)}MB",
            field="file"
        )


async def save_file_async(file: UploadFile, destination: Path) -> None:
    """Save uploaded file asynchronously"""
    content = await file.read()
    loop = asyncio.get_event_loop()
    await loop.run_in_executor(None, lambda: destination.write_bytes(content))


@router.post("/upload", response_model=ApiResponse)
async def upload_file(
    project_id: UUID,
    file: UploadFile = File(...),
    db: AsyncSession = Depends(get_db)
):
    """Upload a file"""
    try:
        # Read file content for validation
        content = await file.read()
        file_size = len(content)

        # Validate file
        validate_file(file.filename, file_size)

        # Save file to disk - 使用项目 raw 目录
        safe_filename = f"{uuid4().hex[:8]}_{file.filename}"
        project_dir = get_project_raw_dir(str(project_id))
        file_path = project_dir / safe_filename

        # Write file asynchronously
        await asyncio.get_event_loop().run_in_executor(
            None,
            lambda: file_path.write_bytes(content)
        )

        # Create file record
        db_file = FileModel(
            project_id=project_id,
            filename=file.filename,
            file_type=get_file_type(file.filename),
            file_path=str(file_path),
            size=file_size,
            status="processing"
        )
        db.add(db_file)
        await db.commit()
        await db.refresh(db_file)

        # 异步处理文件：立即返回，不等待处理完成
        async def process_file_async(file_id: UUID, file_path_obj: Path, file_type: str, filename: str, project_id_val: UUID):
            """后台异步处理文件"""
            from sqlalchemy.ext.asyncio import AsyncSession
            from app.core.database import AsyncSessionLocal

            async with AsyncSessionLocal() as processing_db:
                try:
                    # 重新获取文件记录
                    file_record = await file_crud.get(processing_db, file_id)
                    if not file_record:
                        return

                    # 支持 markitdown 转换的文件类型
                    markitdown_types = ["pdf", "docx", "doc", "pptx", "ppt", "xlsx", "xls", "htm", "html"]
                    text_content = ""

                    if file_type in markitdown_types:
                        # 使用 markitdown 转换为 markdown
                        loop = asyncio.get_event_loop()
                        result = await loop.run_in_executor(
                            None,
                            lambda: markitdown.convert(str(file_path_obj))
                        )
                        text_content = result.text_content
                    else:
                        # txt, md 等直接读取
                        text_content = file_path_obj.read_text(encoding='utf-8')

                    # 保存到 ready 目录
                    ready_dir = get_project_ready_dir(str(project_id_val))
                    ready_filename = f"{file_id}.md"
                    ready_path = ready_dir / ready_filename
                    ready_path.write_text(text_content, encoding='utf-8')

                    # 更新文件状态为处理完成
                    file_record.status = "completed"
                    await processing_db.commit()

                    log_success(
                        "文件处理完成",
                        project_id=str(project_id_val),
                        file_id=str(file_id),
                        filename=filename,
                        ready_path=str(ready_path)
                    )

                except Exception as e:
                    # 更新文件状态为处理失败
                    file_record = await file_crud.get(processing_db, file_id)
                    if file_record:
                        file_record.status = "failed"
                        await processing_db.commit()

                    log_failure(
                        "文件处理失败",
                        project_id=str(project_id_val),
                        file_id=str(file_id),
                        filename=filename,
                        error=str(e)
                    )

        # 启动异步任务处理文件
        asyncio.create_task(
            process_file_async(
                db_file.id,
                file_path,
                db_file.file_type,
                file.filename,
                project_id
            )
        )

        return ApiResponse.ok(
            data={"id": str(db_file.id), "filename": db_file.filename, "status": db_file.status},
            message="File uploaded successfully, processing in background"
        )
    except Exception as e:
        # 记录失败日志
        log_failure(
            "文件上传失败",
            project_id=str(project_id),
            filename=file.filename if 'file' in locals() else "unknown",
            error=str(e)
        )
        raise


@router.get("", response_model=ApiResponse)
async def list_files(
    project_id: UUID,
    page: int = Query(1, ge=1),
    page_size: int = Query(20, ge=1, le=100),
    db: AsyncSession = Depends(get_db)
):
    """List files for a project"""
    skip = (page - 1) * page_size
    files, total = await file_crud.get_multi(
        db,
        skip=skip,
        limit=page_size,
        filters={"project_id": project_id},
        order_by="created_at",
        descending=True
    )

    file_responses = [FileResponse.model_validate(f) for f in files]
    return PaginatedResponse.ok(
        items=file_responses,
        page=page,
        page_size=page_size,
        total=total
    )


@router.get("/{file_id}", response_model=ApiResponse)
async def get_file(
    project_id: UUID,
    file_id: UUID,
    db: AsyncSession = Depends(get_db)
):
    """Get file by ID"""
    file = await file_crud.get(db, file_id)
    if not file or file.project_id != project_id:
        raise NotFoundException("File", file_id)

    return ApiResponse.ok(data=FileResponse.model_validate(file))


@router.get("/{file_id}/raw")
async def get_file_raw(
    project_id: UUID,
    file_id: UUID,
    db: AsyncSession = Depends(get_db)
):
    """Get raw file content for preview"""
    file = await file_crud.get(db, file_id)
    if not file or file.project_id != project_id:
        raise NotFoundException("File", file_id)

    # 读取 raw 目录中的原始文件
    raw_path = Path(file.file_path)

    if not raw_path.exists():
        raise NotFoundException("File not found on disk", file_id)

    # 根据文件类型返回不同的内容
    if file.file_type in ['txt', 'md', 'markdown', 'csv']:
        content = raw_path.read_text(encoding='utf-8')
        return PlainTextResponse(content=content, media_type="text/plain; charset=utf-8")
    elif file.file_type == 'pdf':
        # 返回PDF文件，浏览器可以内嵌显示
        import base64
        content = raw_path.read_bytes()
        b64 = base64.b64encode(content).decode('utf-8')
        return PlainTextResponse(
            content=f"data:application/pdf;base64,{b64}",
            media_type="text/plain"
        )
    else:
        # 其他二进制文件，返回文件信息
        size_mb = file.size / (1024 * 1024)
        content = f"""[二进制文件]

文件名: {file.filename}
文件类型: {file.file_type.upper()}
文件大小: {size_mb:.2f} MB

此文件为二进制格式，请下载后查看。
"""
        return PlainTextResponse(content=content, media_type="text/plain; charset=utf-8")


@router.get("/{file_id}/content")
async def get_file_content(
    project_id: UUID,
    file_id: UUID,
    db: AsyncSession = Depends(get_db)
) -> PlainTextResponse:
    """Get file content (markdown)"""
    file = await file_crud.get(db, file_id)
    if not file or file.project_id != project_id:
        raise NotFoundException("File", file_id)

    # 读取 ready 目录中的 markdown 文件
    ready_path = Path("/data/code/YG-Datasets/data") / str(project_id) / "ready" / f"{file_id}.md"

    if ready_path.exists():
        content = ready_path.read_text(encoding='utf-8')
        return PlainTextResponse(content=content, media_type="text/plain; charset=utf-8")
    else:
        raise NotFoundException("File content", file_id)


@router.delete("/{file_id}", response_model=ApiResponse)
async def delete_file(
    project_id: UUID,
    file_id: UUID,
    db: AsyncSession = Depends(get_db)
):
    """Delete file"""
    file = await file_crud.get(db, file_id)
    if not file or file.project_id != project_id:
        raise NotFoundException("File", file_id)

    # Delete file from raw directory
    if file.file_path and os.path.exists(file.file_path):
        await asyncio.get_event_loop().run_in_executor(
            None,
            os.remove,
            file.file_path
        )

    # Delete file from ready directory (processed markdown)
    ready_path = Path("/data/code/YG-Datasets/data") / str(project_id) / "ready" / f"{file_id}.md"
    if ready_path.exists():
        await asyncio.get_event_loop().run_in_executor(
            None,
            os.remove,
            str(ready_path)
        )

    await file_crud.delete(db, file_id)
    return ApiResponse.ok(message="File deleted successfully")


@router.get("/{file_id}/download")
async def download_file(
    project_id: UUID,
    file_id: UUID,
    db: AsyncSession = Depends(get_db)
) -> FileResponse:
    """Download file"""
    file = await file_crud.get(db, file_id)
    if not file or file.project_id != project_id:
        raise NotFoundException("File", file_id)

    if not file.file_path or not os.path.exists(file.file_path):
        raise ValidationException("File not found on disk", field="file")

    return FileResponse(
        path=file.file_path,
        filename=file.filename,
        media_type=f"application/{file.file_type}"
    )