"""REST API детекции дефектов окраски кузова (по ТЗ АвтоВАЗа, таблица 3).

Эндпоинты:
  POST /predict        — приём фото детали (multipart), VIN — параметром формы;
                         возвращает JSON с дефектами, координатами и base64-визуализацией.
  GET  /defects/{vin}  — последние результаты по VIN (in-memory история).
  GET  /health         — проверка состояния сервиса.

Запуск:
    uvicorn src.api:app --host 0.0.0.0 --port 8080
"""
from __future__ import annotations
import base64
import io
import time
from collections import defaultdict, deque
from datetime import datetime
from typing import Any

import cv2
import numpy as np
import torch
from fastapi import FastAPI, File, Form, HTTPException, UploadFile
from fastapi.responses import FileResponse, JSONResponse
from fastapi.staticfiles import StaticFiles
from pydantic import BaseModel, Field

from . import config as C
from .infer import load_model, predict_image, render_visualization


app = FastAPI(
    title="Paint Defect Detection API",
    version="1.0.0",
    description="Система автоматической детекции дефектов лакокрасочного покрытия "
                "(крыша, капот, багажник). Соответствует требованиям ТЗ АвтоВАЗ.",
)

_device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
_model = None  # ленивая загрузка
_history: dict[str, deque] = defaultdict(lambda: deque(maxlen=20))

_STATIC_DIR = C.ROOT / "static"
if _STATIC_DIR.exists():
    app.mount("/static", StaticFiles(directory=str(_STATIC_DIR)), name="static")


@app.get("/", include_in_schema=False)
def index():
    """Веб-интерфейс оператора (одностраничное приложение)."""
    idx = _STATIC_DIR / "index.html"
    if idx.exists():
        return FileResponse(str(idx))
    raise HTTPException(status_code=404, detail="UI not built")


def _ensure_model():
    global _model
    if _model is None:
        _model = load_model(device=_device)
    return _model


class DefectBox(BaseModel):
    x: int; y: int; w: int; h: int
    confidence: float
    mean_prob: float


class PredictResponse(BaseModel):
    vin: str
    timestamp: str
    is_defect: bool
    defect_count: int
    defect_ratio: float
    max_prob: float
    boxes: list[DefectBox]
    panel_size: dict[str, int]
    visualization_base64: str = Field(description="JPEG, base64-encoded, для отображения на ТВ-панели")
    elapsed_ms: int


@app.get("/health")
def health() -> dict[str, Any]:
    return {
        "status": "ok",
        "device": str(_device),
        "model_loaded": _model is not None,
        "checkpoint": str(C.CHECKPOINTS / "best.pt"),
    }


@app.post("/predict", response_model=PredictResponse)
async def predict(
    file: UploadFile = File(..., description="Фото детали кузова"),
    vin: str = Form(..., description="VIN автомобиля"),
    part: str = Form("unknown", description="Деталь: roof|hood|trunk"),
    threshold: float = Form(C.DEFECT_THRESHOLD),
) -> PredictResponse:
    if not file.content_type or not file.content_type.startswith("image/"):
        raise HTTPException(status_code=400, detail="Ожидался image/*")
    raw = await file.read()
    arr = np.frombuffer(raw, dtype=np.uint8)
    bgr = cv2.imdecode(arr, cv2.IMREAD_COLOR)
    if bgr is None:
        raise HTTPException(status_code=400, detail="Не удалось декодировать изображение")

    model = _ensure_model()
    t0 = time.time()
    result = predict_image(bgr, model, _device, threshold=threshold)
    elapsed_ms = int((time.time() - t0) * 1000)

    vis = render_visualization(result)
    ok, buf = cv2.imencode(".jpg", vis, [cv2.IMWRITE_JPEG_QUALITY, 88])
    vis_b64 = base64.b64encode(buf.tobytes()).decode("ascii") if ok else ""

    response = PredictResponse(
        vin=vin,
        timestamp=datetime.utcnow().isoformat() + "Z",
        is_defect=result["is_defect"],
        defect_count=len(result["boxes"]),
        defect_ratio=result["defect_ratio"],
        max_prob=result["max_prob"],
        boxes=[DefectBox(**b) for b in result["boxes"]],
        panel_size=result["panel_size"],
        visualization_base64=vis_b64,
        elapsed_ms=elapsed_ms,
    )
    _history[vin].append({"part": part, "ts": response.timestamp,
                          "is_defect": response.is_defect,
                          "defect_count": response.defect_count})
    return response


@app.get("/defects/{vin}")
def defects_by_vin(vin: str) -> dict[str, Any]:
    return {"vin": vin, "results": list(_history.get(vin, []))}


def main():
    import uvicorn
    uvicorn.run("src.api:app", host=C.API_HOST, port=C.API_PORT, reload=False)


if __name__ == "__main__":
    main()