"""API routes for report generation

FastAPI router with all report-related endpoints:
- POST /api/rooms/{room_id}/reports/generate - Trigger report generation
- GET /api/rooms/{room_id}/reports - List reports for a room
- GET /api/rooms/{room_id}/reports/{report_id} - Get report status/metadata
- GET /api/rooms/{room_id}/reports/{report_id}/download - Download report .docx
"""
import logging
from urllib.parse import quote
from fastapi import APIRouter, Depends, HTTPException, status, BackgroundTasks
from fastapi.responses import StreamingResponse
from sqlalchemy.orm import Session
from typing import Optional
import io

from app.core.database import get_db
from app.core.config import get_settings
from app.core.minio_client import get_minio_client
from app.modules.auth import get_current_user
from app.modules.report_generation import schemas
from app.modules.report_generation.models import GeneratedReport, ReportStatus
from app.modules.report_generation.dependencies import require_room_member
from app.modules.report_generation.services.report_data_service import ReportDataService
from app.modules.report_generation.services.dify_client import (
    dify_service,
    DifyAPIError,
    DifyJSONParseError,
    DifyValidationError,
)
from app.modules.report_generation.services.docx_service import docx_service
from app.modules.report_generation.prompts import build_report_prompt
from app.modules.realtime.websocket_manager import manager as ws_manager

settings = get_settings()
logger = logging.getLogger(__name__)


async def _broadcast_report_progress(
    room_id: str,
    report_id: str,
    status: str,
    message: str,
    error: str = None,
):
    """Broadcast report generation progress via WebSocket

    Args:
        room_id: Room ID to broadcast to
        report_id: Report ID
        status: Current status (pending, collecting_data, generating_content, etc.)
        message: Human-readable progress message
        error: Error message if failed
    """
    payload = {
        "type": "report_progress",
        "report_id": report_id,
        "room_id": room_id,
        "status": status,
        "message": message,
    }
    if error:
        payload["error"] = error

    await ws_manager.broadcast_to_room(room_id, payload)

router = APIRouter(prefix="/api/rooms/{room_id}/reports", tags=["Report Generation"])
health_router = APIRouter(prefix="/api/reports", tags=["Report Generation"])


@health_router.get("/health", response_model=schemas.HealthCheckResponse)
async def check_dify_health():
    """Check DIFY AI service connection status

    Returns:
        Health check result with status and message
    """
    if not settings.DIFY_API_KEY:
        return schemas.HealthCheckResponse(
            status="error",
            message="DIFY_API_KEY 未設定，請聯繫系統管理員"
        )

    try:
        result = await dify_service.test_connection()
        return schemas.HealthCheckResponse(
            status=result["status"],
            message=result["message"]
        )
    except DifyAPIError as e:
        return schemas.HealthCheckResponse(
            status="error",
            message=str(e)
        )


@router.post("/generate", response_model=schemas.ReportGenerateResponse, status_code=status.HTTP_202_ACCEPTED)
async def generate_report(
    room_id: str,
    request: schemas.ReportGenerateRequest = None,
    background_tasks: BackgroundTasks = None,
    db: Session = Depends(get_db),
    room_context: dict = Depends(require_room_member),
):
    """Trigger AI report generation for a room

    This endpoint starts an async report generation process:
    1. Collects room data (messages, members, files)
    2. Sends data to DIFY AI for content generation
    3. Assembles .docx document with AI content and images
    4. Stores report in MinIO

    Args:
        room_id: Room ID to generate report for
        request: Optional generation parameters

    Returns:
        Report ID and initial status
    """
    if request is None:
        request = schemas.ReportGenerateRequest()

    user_email = room_context["user_email"]

    # Create report record with pending status
    report = GeneratedReport(
        room_id=room_id,
        generated_by=user_email,
        status=ReportStatus.PENDING.value,
    )
    db.add(report)
    db.commit()
    db.refresh(report)

    # Start background generation task
    background_tasks.add_task(
        _generate_report_task,
        report_id=report.report_id,
        room_id=room_id,
        include_images=request.include_images,
        include_file_list=request.include_file_list,
    )

    return schemas.ReportGenerateResponse(
        report_id=report.report_id,
        status=schemas.ReportStatus.PENDING,
        message="Report generation started",
    )


@router.get("", response_model=schemas.ReportListResponse)
async def list_reports(
    room_id: str,
    db: Session = Depends(get_db),
    room_context: dict = Depends(require_room_member),
):
    """List all reports for a room

    Args:
        room_id: Room ID to list reports for

    Returns:
        List of report summaries sorted by generation time (newest first)
    """
    reports = (
        db.query(GeneratedReport)
        .filter(GeneratedReport.room_id == room_id)
        .order_by(GeneratedReport.generated_at.desc())
        .all()
    )

    items = [
        schemas.ReportListItem(
            report_id=r.report_id,
            generated_at=r.generated_at,
            generated_by=r.generated_by,
            status=schemas.ReportStatus(r.status),
            report_title=r.report_title,
        )
        for r in reports
    ]

    return schemas.ReportListResponse(
        reports=items,
        total=len(items),
    )


@router.get("/{report_id}", response_model=schemas.ReportStatusResponse)
async def get_report_status(
    room_id: str,
    report_id: str,
    db: Session = Depends(get_db),
    room_context: dict = Depends(require_room_member),
):
    """Get report status and metadata

    Args:
        room_id: Room ID
        report_id: Report ID to get status for

    Returns:
        Report metadata including status, token usage, etc.
    """
    report = (
        db.query(GeneratedReport)
        .filter(
            GeneratedReport.report_id == report_id,
            GeneratedReport.room_id == room_id,
        )
        .first()
    )

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

    return schemas.ReportStatusResponse(
        report_id=report.report_id,
        room_id=report.room_id,
        generated_by=report.generated_by,
        generated_at=report.generated_at,
        status=schemas.ReportStatus(report.status),
        error_message=report.error_message,
        report_title=report.report_title,
        prompt_tokens=report.prompt_tokens,
        completion_tokens=report.completion_tokens,
    )


@router.get("/{report_id}/markdown", response_model=schemas.ReportMarkdownResponse)
async def get_report_markdown(
    room_id: str,
    report_id: str,
    db: Session = Depends(get_db),
    room_context: dict = Depends(require_room_member),
):
    """Get report content as Markdown for in-page preview

    Args:
        room_id: Room ID
        report_id: Report ID to get markdown for

    Returns:
        Markdown formatted report content
    """
    report = (
        db.query(GeneratedReport)
        .filter(
            GeneratedReport.report_id == report_id,
            GeneratedReport.room_id == room_id,
        )
        .first()
    )

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

    if report.status != ReportStatus.COMPLETED.value:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=f"Report is not ready. Status: {report.status}",
        )

    if not report.report_json:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Report content not found",
        )

    # Collect room data for markdown generation
    data_service = ReportDataService(db)
    room_data = data_service.collect_room_data(room_id)

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

    prompt_data = data_service.to_prompt_dict(room_data)

    # Generate markdown
    markdown_content = docx_service.to_markdown(
        room_data=prompt_data["room_data"],
        ai_content=report.report_json,
        files=prompt_data["files"],
    )

    return schemas.ReportMarkdownResponse(
        report_id=report.report_id,
        report_title=report.report_title,
        markdown=markdown_content,
    )


@router.get("/{report_id}/download")
async def download_report(
    room_id: str,
    report_id: str,
    db: Session = Depends(get_db),
    room_context: dict = Depends(require_room_member),
):
    """Download generated report as .docx

    Args:
        room_id: Room ID
        report_id: Report ID to download

    Returns:
        StreamingResponse with .docx file
    """
    report = (
        db.query(GeneratedReport)
        .filter(
            GeneratedReport.report_id == report_id,
            GeneratedReport.room_id == room_id,
        )
        .first()
    )

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

    if report.status != ReportStatus.COMPLETED.value:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=f"Report is not ready for download. Status: {report.status}",
        )

    if not report.docx_storage_path:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Report file not found in storage",
        )

    # Download from MinIO
    try:
        minio_client = get_minio_client()
        response = minio_client.get_object(
            settings.MINIO_BUCKET,
            report.docx_storage_path,
        )

        # Read file content
        content = response.read()
        response.close()
        response.release_conn()

        # Create filename from report title or ID
        filename = report.report_title or f"report_{report.report_id[:8]}"
        filename = f"{filename}.docx"

        # Use RFC 5987 format for non-ASCII filenames
        # Provide ASCII fallback for older clients + UTF-8 encoded version
        ascii_filename = f"report_{report.report_id[:8]}.docx"
        encoded_filename = quote(filename)

        return StreamingResponse(
            io.BytesIO(content),
            media_type="application/vnd.openxmlformats-officedocument.wordprocessingml.document",
            headers={
                "Content-Disposition": f"attachment; filename=\"{ascii_filename}\"; filename*=UTF-8''{encoded_filename}",
            },
        )

    except Exception as e:
        logger.error(f"Failed to download report from MinIO: {e}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail="Failed to retrieve report file",
        )


async def _generate_report_task(
    report_id: str,
    room_id: str,
    include_images: bool = True,
    include_file_list: bool = True,
):
    """Background task to generate report

    This task:
    1. Updates status to COLLECTING_DATA + WebSocket notification
    2. Collects room data
    3. Updates status to GENERATING_CONTENT + WebSocket notification
    4. Calls DIFY AI for content
    5. Updates status to ASSEMBLING_DOCUMENT + WebSocket notification
    6. Creates .docx document
    7. Uploads to MinIO
    8. Updates status to COMPLETED (or FAILED) + WebSocket notification
    """
    from app.core.database import SessionLocal

    db = SessionLocal()

    try:
        report = db.query(GeneratedReport).filter(
            GeneratedReport.report_id == report_id
        ).first()

        if not report:
            logger.error(f"Report not found: {report_id}")
            return

        # Phase 1: Collecting Data
        report.status = ReportStatus.COLLECTING_DATA.value
        db.commit()
        await _broadcast_report_progress(
            room_id, report_id, "collecting_data", "正在收集聊天室資料..."
        )

        data_service = ReportDataService(db)
        room_data = data_service.collect_room_data(room_id)

        if not room_data:
            report.status = ReportStatus.FAILED.value
            report.error_message = "Room not found"
            db.commit()
            await _broadcast_report_progress(
                room_id, report_id, "failed", "報告生成失敗", error="找不到聊天室"
            )
            return

        # Convert to dict for prompt builder
        prompt_data = data_service.to_prompt_dict(room_data)

        # Phase 2: Generating Content
        report.status = ReportStatus.GENERATING_CONTENT.value
        db.commit()
        await _broadcast_report_progress(
            room_id, report_id, "generating_content", "AI 正在分析並生成報告內容..."
        )

        # Build prompt and call DIFY
        prompt = build_report_prompt(
            room_data=prompt_data["room_data"],
            messages=prompt_data["messages"],
            members=prompt_data["members"],
            files=prompt_data["files"],
        )

        try:
            dify_response = await dify_service.generate_report(prompt, room_id)
        except (DifyAPIError, DifyJSONParseError, DifyValidationError) as e:
            report.status = ReportStatus.FAILED.value
            report.error_message = str(e)
            db.commit()
            await _broadcast_report_progress(
                room_id, report_id, "failed", "AI 生成失敗", error=str(e)
            )
            logger.error(f"DIFY error for report {report_id}: {e}")
            return

        # Save AI response data
        report.dify_message_id = dify_response.message_id
        report.dify_conversation_id = dify_response.conversation_id
        report.prompt_tokens = dify_response.prompt_tokens
        report.completion_tokens = dify_response.completion_tokens
        report.report_json = dify_response.parsed_json

        # Extract title from summary
        ai_content = dify_response.parsed_json
        if ai_content and "summary" in ai_content:
            summary_content = ai_content["summary"].get("content", "")
            # Use first 50 chars of summary as title
            report.report_title = summary_content[:50] + "..." if len(summary_content) > 50 else summary_content

        db.commit()

        # Phase 3: Assembling Document
        report.status = ReportStatus.ASSEMBLING_DOCUMENT.value
        db.commit()
        await _broadcast_report_progress(
            room_id, report_id, "assembling_document", "正在組裝報告文件..."
        )

        try:
            docx_data = docx_service.create_report(
                room_data=prompt_data["room_data"],
                ai_content=ai_content,
                files=prompt_data["files"],
                include_images=include_images,
                include_file_list=include_file_list,
            )
        except Exception as e:
            report.status = ReportStatus.FAILED.value
            report.error_message = f"Document assembly failed: {str(e)}"
            db.commit()
            await _broadcast_report_progress(
                room_id, report_id, "failed", "文件組裝失敗", error=str(e)
            )
            logger.error(f"Document assembly error for report {report_id}: {e}")
            return

        # Upload to MinIO
        storage_path = docx_service.upload_report(
            report_data=docx_data,
            room_id=room_id,
            report_id=report_id,
        )

        if not storage_path:
            report.status = ReportStatus.FAILED.value
            report.error_message = "Failed to upload report to storage"
            db.commit()
            await _broadcast_report_progress(
                room_id, report_id, "failed", "報告上傳失敗", error="無法上傳到儲存空間"
            )
            return

        # Phase 4: Completed
        report.docx_storage_path = storage_path
        report.status = ReportStatus.COMPLETED.value
        db.commit()
        await _broadcast_report_progress(
            room_id, report_id, "completed", "報告生成完成！"
        )

        logger.info(f"Report generation completed: {report_id}")

    except Exception as e:
        logger.error(f"Unexpected error generating report {report_id}: {e}")
        try:
            report = db.query(GeneratedReport).filter(
                GeneratedReport.report_id == report_id
            ).first()
            if report:
                report.status = ReportStatus.FAILED.value
                report.error_message = f"Unexpected error: {str(e)}"
                db.commit()
            await _broadcast_report_progress(
                room_id, report_id, "failed", "發生未預期的錯誤", error=str(e)
            )
        except Exception:
            pass

    finally:
        db.close()