from datetime import date
from fastapi import APIRouter, Depends, Request
from fastapi.responses import HTMLResponse
from sqlalchemy.orm import Session
from app.database import get_db
from app.models import DailyBar, Contract

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

WEEKDAY_ZH = {0: "周一", 1: "周二", 2: "周三", 3: "周四", 4: "周五", 5: "周六", 6: "周日"}


def get_active_contracts(db: Session) -> list[str]:
    contracts = (
        db.query(Contract.code)
        .filter(Contract.is_active == True)
        .order_by(Contract.code)
        .all()
    )
    return [c[0] for c in contracts]


@router.get("/", response_class=HTMLResponse)
def contract_index(request: Request, db: Session = Depends(get_db)):
    active_contracts = get_active_contracts(db)

    latest = (
        db.query(DailyBar)
        .filter(DailyBar.contract.in_(active_contracts))
        .order_by(DailyBar.date.desc())
        .all()
    )
    contract_bars = {}
    for bar in latest:
        if bar.contract not in contract_bars:
            contract_bars[bar.contract] = bar

    total_bars = db.query(DailyBar).count()
    latest_bar = (
        db.query(DailyBar).order_by(DailyBar.date.desc()).first()
    )

    template = request.app.state.templates.get_template("index.html")
    return HTMLResponse(
        template.render(
            request=request,
            active_nav="contracts",
            contracts=active_contracts,
            contract_bars=contract_bars,
            total_bars=total_bars,
            latest_date=latest_bar.date.strftime("%Y-%m-%d") if latest_bar else "—",
        )
    )


@router.get("/{contract}", response_class=HTMLResponse)
def contract_detail(request: Request, contract: str, db: Session = Depends(get_db)):
    active_contracts = get_active_contracts(db)
    bars = (
        db.query(DailyBar)
        .filter(DailyBar.contract == contract.upper())
        .order_by(DailyBar.date.desc())
        .all()
    )

    rows = []
    for bar in bars:
        rows.append({
            "date": bar.date.strftime("%Y/%-m/%-d"),
            "weekday": WEEKDAY_ZH.get(bar.date.weekday(), ""),
            "open": int(bar.open) if bar.open else "-",
            "close": int(bar.close) if bar.close else "-",
            "high": int(bar.high) if bar.high else "-",
            "low": int(bar.low) if bar.low else "-",
            "diff": int(bar.diff) if bar.diff else 0,
            "amp_5d": int(bar.amp_5d) if bar.amp_5d is not None else None,
            "has_amp": bar.amp_5d is not None,
        })

    latest = bars[0] if bars else None

    # Predict next trading day amplitude: mean of latest 5 diffs
    next_amp = None
    if len(bars) >= 5:
        next_amp = round(sum(b.diff for b in bars[:5]) / 5)

    template = request.app.state.templates.get_template("contract.html")
    return HTMLResponse(
        template.render(
            request=request,
            active_nav="contracts",
            contract=contract.upper(),
            contracts=active_contracts,
            rows=rows,
            latest=latest,
            next_amp=next_amp,
            row_count=len(rows),
        )
    )