from typing import List

from fastapi import APIRouter, Depends, File, HTTPException, Query, UploadFile
from fastapi.responses import FileResponse
from sqlalchemy.orm import Session

from backend.app.db import get_db
from backend.app import models
from backend.app.schemas import (
    FinanceRecordRead,
    FinanceRecordUpdate,
    FinanceSyncResponse,
    FinanceSyncResult,
    FinanceUploadResponse,
)
from backend.app.services.email_service import create_monthly_zip, sync_finance_emails
from backend.app.services.invoice_upload import process_invoice_upload


router = APIRouter(prefix="/finance", tags=["finance"])


@router.post("/sync", response_model=FinanceSyncResponse)
async def sync_finance():
    try:
        items_raw = await sync_finance_emails()
    except RuntimeError as exc:
        # 邮箱配置/连接等问题属于可预期的业务错误，用 400 让前端直接展示原因，而不是泛化为 500。
        raise HTTPException(status_code=400, detail=str(exc)) from exc

    details = [FinanceSyncResult(**item) for item in items_raw]
    return FinanceSyncResponse(
        status="success",
        new_files=len(details),
        details=details,
    )


@router.get("/months", response_model=List[str])
async def list_finance_months(db: Session = Depends(get_db)):
    """List distinct months that have finance records (YYYY-MM), newest first."""
    from sqlalchemy import distinct

    rows = (
        db.query(distinct(models.FinanceRecord.month))
        .order_by(models.FinanceRecord.month.desc())
        .all()
    )
    return [r[0] for r in rows]


@router.get("/records", response_model=List[FinanceRecordRead])
async def list_finance_records(
    month: str = Query(..., description="YYYY-MM"),
    db: Session = Depends(get_db),
):
    """List finance records for a given month."""
    records = (
        db.query(models.FinanceRecord)
        .filter(models.FinanceRecord.month == month)
        .order_by(models.FinanceRecord.created_at.desc())
        .all()
    )
    return records


@router.post("/upload", response_model=FinanceUploadResponse, status_code=201)
async def upload_invoice(
    file: UploadFile = File(...),
    db: Session = Depends(get_db),
):
    """Upload an invoice (PDF or image). Saves to data/finance/{YYYY-MM}/manual/, runs AI OCR for amount/date."""
    suf = (file.filename or "").lower().split(".")[-1] if "." in (file.filename or "") else ""
    allowed = {"pdf", "jpg", "jpeg", "png", "webp"}
    if suf not in allowed:
        raise HTTPException(400, "仅支持 PDF、JPG、PNG、WEBP 格式")
    file_name, file_path, month_str, amount, billing_date = await process_invoice_upload(file)
    record = models.FinanceRecord(
        month=month_str,
        type="manual",
        file_name=file_name,
        file_path=file_path,
        amount=amount,
        billing_date=billing_date,
    )
    db.add(record)
    db.commit()
    db.refresh(record)
    return record


@router.patch("/records/{record_id}", response_model=FinanceRecordRead)
async def update_finance_record(
    record_id: int,
    payload: FinanceRecordUpdate,
    db: Session = Depends(get_db),
):
    """Update amount and/or billing_date of a finance record (e.g. after manual review)."""
    record = db.query(models.FinanceRecord).get(record_id)
    if not record:
        raise HTTPException(404, "记录不存在")
    if payload.amount is not None:
        record.amount = payload.amount
    if payload.billing_date is not None:
        record.billing_date = payload.billing_date
    db.commit()
    db.refresh(record)
    return record


@router.get("/download/{month}")
async def download_finance_month(month: str):
    """
    Download a zipped archive for a given month (YYYY-MM).
    """
    try:
        zip_path = await create_monthly_zip(month)
    except FileNotFoundError as exc:
        raise HTTPException(status_code=404, detail=str(exc)) from exc

    return FileResponse(
        path=zip_path,
        media_type="application/zip",
        filename=f"finance_{month}.zip",
    )