import uuid
from datetime import date
from fastapi import APIRouter, HTTPException, status
from fastapi.responses import Response
from sqlalchemy import select, func
from app.deps import CurrentUser, DB
from app.models.report import Report, ReportType
from app.models.daily_report import DailyReport
from app.models.weather import WeatherAlert
from app.models.project import Project
from app.schemas.report import ReportGenerateRequest, ReportResponse
from app.services.report_gen import generate_weekly_report, generate_monthly_report
from app.services.pdf_service import generate_report_pdf

router = APIRouter(prefix="/projects/{project_id}/reports", tags=["공정보고서"])


# Report schemas (inline for simplicity)
from pydantic import BaseModel
from app.models.report import ReportType, ReportStatus


class ReportGenerateRequest(BaseModel):
    report_type: ReportType
    period_start: date
    period_end: date


class ReportResponse(BaseModel):
    id: uuid.UUID
    project_id: uuid.UUID
    report_type: ReportType
    period_start: date
    period_end: date
    ai_draft_text: str | None
    status: ReportStatus
    pdf_s3_key: str | None

    model_config = {"from_attributes": True}


async def _get_project_or_404(project_id: uuid.UUID, db: DB) -> Project:
    result = await db.execute(select(Project).where(Project.id == project_id))
    p = result.scalar_one_or_none()
    if not p:
        raise HTTPException(status_code=404, detail="프로젝트를 찾을 수 없습니다")
    return p


def _compute_overall_progress(tasks) -> float:
    if not tasks:
        return 0.0
    total = sum(t.progress_pct for t in tasks)
    return total / len(tasks)


@router.get("", response_model=list[ReportResponse])
async def list_reports(project_id: uuid.UUID, db: DB, current_user: CurrentUser):
    result = await db.execute(
        select(Report)
        .where(Report.project_id == project_id)
        .order_by(Report.period_start.desc())
    )
    return result.scalars().all()


@router.post("/generate", response_model=ReportResponse, status_code=status.HTTP_201_CREATED)
async def generate_report(project_id: uuid.UUID, data: ReportGenerateRequest, db: DB, current_user: CurrentUser):
    """AI-generate weekly or monthly report draft."""
    project = await _get_project_or_404(project_id, db)

    # Get daily reports in period
    daily_result = await db.execute(
        select(DailyReport).where(
            DailyReport.project_id == project_id,
            DailyReport.report_date >= data.period_start,
            DailyReport.report_date <= data.period_end,
        ).order_by(DailyReport.report_date)
    )
    daily_reports = daily_result.scalars().all()

    # Get tasks for progress
    from app.models.task import Task
    tasks_result = await db.execute(select(Task).where(Task.project_id == project_id))
    tasks = tasks_result.scalars().all()
    overall_progress = _compute_overall_progress(tasks)

    if data.report_type == ReportType.WEEKLY:
        # Get weather alerts in period
        alerts_result = await db.execute(
            select(WeatherAlert).where(
                WeatherAlert.project_id == project_id,
                WeatherAlert.alert_date >= data.period_start,
                WeatherAlert.alert_date <= data.period_end,
            )
        )
        weather_alerts = alerts_result.scalars().all()

        ai_text, content_json = await generate_weekly_report(
            project_name=project.name,
            period_start=str(data.period_start),
            period_end=str(data.period_end),
            daily_reports=daily_reports,
            overall_progress_pct=overall_progress,
            weather_alerts=weather_alerts,
        )
    else:
        ai_text, content_json = await generate_monthly_report(
            project_name=project.name,
            period_start=str(data.period_start),
            period_end=str(data.period_end),
            daily_reports=daily_reports,
            overall_progress_pct=overall_progress,
        )

    report = Report(
        project_id=project_id,
        report_type=data.report_type,
        period_start=data.period_start,
        period_end=data.period_end,
        content_json=content_json,
        ai_draft_text=ai_text,
    )
    db.add(report)
    await db.commit()
    await db.refresh(report)
    return report


@router.get("/{report_id}", response_model=ReportResponse)
async def get_report(project_id: uuid.UUID, report_id: uuid.UUID, db: DB, current_user: CurrentUser):
    result = await db.execute(select(Report).where(Report.id == report_id, Report.project_id == project_id))
    report = result.scalar_one_or_none()
    if not report:
        raise HTTPException(status_code=404, detail="보고서를 찾을 수 없습니다")
    return report


@router.get("/{report_id}/pdf")
async def download_report_pdf(project_id: uuid.UUID, report_id: uuid.UUID, db: DB, current_user: CurrentUser):
    """공정보고서 PDF 다운로드"""
    r = await db.execute(select(Report).where(Report.id == report_id, Report.project_id == project_id))
    report = r.scalar_one_or_none()
    if not report:
        raise HTTPException(status_code=404, detail="보고서를 찾을 수 없습니다")
    project = await _get_project_or_404(project_id, db)
    pdf_bytes = generate_report_pdf(report, project)
    filename = f"report_{report.report_type.value}_{report.period_start}.pdf"
    return Response(content=pdf_bytes, media_type="application/pdf",
                    headers={"Content-Disposition": f"attachment; filename*=UTF-8''{filename}"})


@router.delete("/{report_id}", status_code=status.HTTP_204_NO_CONTENT)
async def delete_report(project_id: uuid.UUID, report_id: uuid.UUID, db: DB, current_user: CurrentUser):
    result = await db.execute(select(Report).where(Report.id == report_id, Report.project_id == project_id))
    report = result.scalar_one_or_none()
    if not report:
        raise HTTPException(status_code=404, detail="보고서를 찾을 수 없습니다")
    await db.delete(report)
    await db.commit()