from fastapi import APIRouter, Depends, HTTPException, Query
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select, func, desc
from typing import Optional
from datetime import datetime

from app.database import get_db
from app.models.quality import QualityRecord
from app.schemas.quality import QualityRecordCreate, QualityRecordUpdate, QualityRecordOut
from app.schemas.common import Response, PageResponse
from app.services.auth_service import get_current_user
from app.services.prediction import QualityPredictionModel

router = APIRouter()


@router.get("/summary", response_model=Response[dict])
async def quality_summary(
    db: AsyncSession = Depends(get_db),
    _=Depends(get_current_user),
):
    """合格率、平均评分、班次分组统计"""
    total_q   = await db.execute(select(func.count()).select_from(QualityRecord))
    passed_q  = await db.execute(
        select(func.count()).select_from(QualityRecord).where(QualityRecord.is_passed == True)
    )
    avg_pi_q  = await db.execute(select(func.avg(QualityRecord.pi_score)).select_from(QualityRecord))
    avg_suf_q = await db.execute(select(func.avg(QualityRecord.surface_score)).select_from(QualityRecord))

    # Grade distribution
    grade_counts: dict = {}
    for grade in ["A1", "A2", "B1", "B2", "C"]:
        cnt_q = await db.execute(
            select(func.count()).select_from(QualityRecord).where(QualityRecord.overall_grade == grade)
        )
        grade_counts[grade] = cnt_q.scalar() or 0

    total  = total_q.scalar() or 0
    passed = passed_q.scalar() or 0
    pass_rate = round(passed / total * 100, 1) if total > 0 else 0.0

    return Response.ok({
        "total":         total,
        "passed":        passed,
        "pass_rate":     pass_rate,
        "avg_pi_score":  round(avg_pi_q.scalar() or 0, 1),
        "avg_surface_score": round(avg_suf_q.scalar() or 0, 1),
        "grade_distribution": grade_counts,
    })


@router.get("/", response_model=Response[PageResponse[QualityRecordOut]])
async def list_quality(
    page:         int = 1,
    page_size:    int = 20,
    coil_no:      Optional[str] = None,
    overall_grade: Optional[str] = None,
    start_date:   Optional[datetime] = None,
    end_date:     Optional[datetime] = None,
    db: AsyncSession = Depends(get_db),
    _=Depends(get_current_user),
):
    query = select(QualityRecord).order_by(desc(QualityRecord.created_at))
    if coil_no:
        query = query.where(QualityRecord.coil_no.ilike(f"%{coil_no}%"))
    if overall_grade:
        query = query.where(QualityRecord.overall_grade == overall_grade)
    _sd = _parse_dt(start_date)
    if _sd:
        query = query.where(QualityRecord.created_at >= _sd)
    _ed = _parse_dt(end_date)
    if _ed:
        query = query.where(QualityRecord.created_at <= _ed)

    total  = (await db.execute(select(func.count()).select_from(query.subquery()))).scalar()
    result = await db.execute(query.offset((page - 1) * page_size).limit(page_size))
    items  = [QualityRecordOut.model_validate(r) for r in result.scalars()]
    return Response.ok(PageResponse(total=total, page=page, page_size=page_size, items=items))


@router.post("/", response_model=Response[QualityRecordOut])
async def create_quality(
    body: QualityRecordCreate,
    db: AsyncSession = Depends(get_db),
    _=Depends(get_current_user),
):
    """
    创建质量记录。若未提供 pi_score / surface_score / overall_grade，
    则尝试用 QualityPredictionModel 自动填充（需要thickness_actual和相关参数）。
    """
    data = body.model_dump()

    if (
        data.get("pi_score") is None
        and data.get("thickness_actual") is not None
    ):
        # Use default avg values for auto-prediction when detailed params are absent
        avg_speed    = 100.0   # m/min default
        acid_conc_avg = 160.0  # g/L default
        acid_temp_avg = 75.0   # °C default
        try:
            pred = QualityPredictionModel(
                thickness=data["thickness_actual"],
                avg_speed=avg_speed,
                acid_conc_avg=acid_conc_avg,
                acid_temp_avg=acid_temp_avg,
            ).calculate()
            data["pi_score"]      = pred["pi_score"]
            data["surface_score"] = pred["surface_score"]
            data["overall_grade"] = pred["overall_grade"]
        except Exception:
            pass  # best-effort, do not block creation

    record = QualityRecord(**data)
    db.add(record)
    await db.flush()
    return Response.ok(QualityRecordOut.model_validate(record))


@router.put("/{quality_id}", response_model=Response[QualityRecordOut])
async def update_quality(
    quality_id: int,
    body: QualityRecordUpdate,
    db: AsyncSession = Depends(get_db),
    _=Depends(get_current_user),
):
    result = await db.execute(select(QualityRecord).where(QualityRecord.id == quality_id))
    record = result.scalar_one_or_none()
    if not record:
        raise HTTPException(status_code=404, detail="质量记录不存在")
    for k, v in body.model_dump(exclude_none=True).items():
        setattr(record, k, v)
    await db.flush()
    return Response.ok(QualityRecordOut.model_validate(record))