import os
from typing import Any, Dict, List, Optional

from fastapi import Depends, FastAPI, Header, HTTPException

API_KEY = os.getenv("ONEOK_ADAPTER_API_KEY", "").strip()
BASE_RATE_PER_M2 = float(os.getenv("ONEOK_BASE_RATE_PER_M2", "3200"))
INSTALL_RATE_PER_M2 = float(os.getenv("ONEOK_INSTALL_RATE_PER_M2", "900"))
CURRENCY = os.getenv("ONEOK_CURRENCY", "UAH")

app = FastAPI(title="1OK Calc Adapter", version="1.0.0")


def _auth(authorization: Optional[str] = Header(default=None)) -> None:
    if not API_KEY:
        return
    expected = f"Bearer {API_KEY}"
    if authorization != expected:
        raise HTTPException(status_code=401, detail="Unauthorized")


def _normalize_units(payload: Dict[str, Any]) -> List[Dict[str, Any]]:
    units = payload.get("window_units")
    if isinstance(units, list) and units:
        return [u for u in units if isinstance(u, dict)]
    # Compatibility alias used by some LLM tool calls.
    units = payload.get("windows")
    if isinstance(units, list) and units:
        return [u for u in units if isinstance(u, dict)]
    # fallback to one unit in root payload
    if "width_mm" in payload and "height_mm" in payload:
        return [payload]
    return []


@app.get("/health")
def health() -> Dict[str, Any]:
    return {"status": "ok", "service": "oneok-calc-adapter"}


@app.post("/calc/window_quote")
def calc_window_quote(input_payload: Dict[str, Any], _: None = Depends(_auth)) -> Dict[str, Any]:
    units = _normalize_units(input_payload)
    if not units:
        raise HTTPException(status_code=400, detail="window_units/windows or width_mm/height_mm required")

    line_items: List[Dict[str, Any]] = []
    subtotal = 0.0

    for idx, unit in enumerate(units, 1):
        width_mm = float(unit.get("width_mm") or 0)
        height_mm = float(unit.get("height_mm") or 0)
        if width_mm <= 0 or height_mm <= 0:
            continue
        area_m2 = (width_mm * height_mm) / 1_000_000.0
        base = round(area_m2 * BASE_RATE_PER_M2, 2)
        install = round(area_m2 * INSTALL_RATE_PER_M2, 2)
        total = round(base + install, 2)
        subtotal += total

        line_items.append(
            {
                "item": unit.get("label") or f"window_{idx}",
                "width_mm": width_mm,
                "height_mm": height_mm,
                "area_m2": round(area_m2, 3),
                "base_price": base,
                "install_price": install,
                "total": total,
            }
        )

    if not line_items:
        raise HTTPException(status_code=400, detail="No valid window units for calculation")

    assumptions = [
        f"Базова ставка: {BASE_RATE_PER_M2} {CURRENCY}/м2",
        f"Монтаж: {INSTALL_RATE_PER_M2} {CURRENCY}/м2",
        "ОЦІНКА: без виїзного підтвердженого заміру ціна попередня.",
    ]

    lead_days = 10
    if str(input_payload.get("urgency", "")).lower() in {"urgent", "терміново"}:
        lead_days = 7

    return {
        "currency": CURRENCY,
        "line_items": line_items,
        "totals": {
            "subtotal": round(subtotal, 2),
            "discount": 0.0,
            "grand_total": round(subtotal, 2),
        },
        "assumptions": assumptions,
        "lead_time_if_known": f"{lead_days} днів",
    }