import json
import os
import pandas as pd
from pathlib import Path


def load_factory_mapping(year: int) -> dict:
    path = os.path.join("data", str(year), "factory_mapping.json")
    with open(path, "r", encoding="utf-8") as f:
        return json.load(f)


def load_model_params(year: int) -> dict:
    path = os.path.join("data", str(year), "model_params.json")
    with open(path, "r", encoding="utf-8") as f:
        return json.load(f)

def load_benchmark_factories(year: int) -> list[str]:
    path = Path("data") / str(year) / "benchmark.csv"
    encodings = ("utf-8", "utf-8-sig", "gbk")
    last_error = None
    df = None
    for enc in encodings:
        try:
            df = pd.read_csv(path, encoding=enc)
            break
        except UnicodeDecodeError as exc:
            last_error = exc
            continue
    if df is None:
        raise last_error if last_error else FileNotFoundError(f"Missing {path}")
    # Assume first column holds factory name (aligns with factory_mapping keys)
    factory_col = df.columns[0]
    return df[factory_col].astype(str).str.strip().unique().tolist()


def build_factory_dataframe(year: int) -> pd.DataFrame:
    mapping = load_factory_mapping(year)
    params = load_model_params(year)
    default_factor = params.get("factor_default", 1)
    benchmark_factories = load_benchmark_factories(year)
    rows = []
    for cn_name in benchmark_factories:
        code = mapping.get(cn_name)
        if code is None:
            raise KeyError(f"benchmark.csv中的工厂“{cn_name}”未在 factory_mapping.json 中找到映射。")
        factor = params.get(f"factor_{code}", default_factor if default_factor is not None else 1)
        rows.append(
            {
                "工厂中文名": cn_name,
                "工厂英文名": code,
                "工厂平均磨合系数": float(factor),
                "最小误差": 1_000_000,
            }
        )
    return pd.DataFrame(rows)


def write_factory_csv(df: pd.DataFrame, year: int) -> str:
    out_path = os.path.join("data", str(year), "factory_data.csv")
    df.to_csv(out_path, index=False, encoding="utf-8-sig")
    return out_path


def main():
    year = 2025
    df = build_factory_dataframe(year)
    out_path = write_factory_csv(df, year)
    print(f"factory_data.csv generated at: {out_path}")


if __name__ == "__main__":
    main()