from __future__ import annotations

import hashlib
from pathlib import Path

import yaml
from django.conf import settings


CONFIG_PATH = Path(__file__).resolve().parents[1] / "templates" / "regulatory_info_package_templates_v1.yaml"


def load_template_config(path: str | Path | None = None) -> dict:
    config_path = Path(path) if path else CONFIG_PATH
    with config_path.open("r", encoding="utf-8") as handle:
        payload = yaml.safe_load(handle) or {}
    if payload.get("source_dir"):
        payload["source_dir"] = str((Path(settings.BASE_DIR) / payload["source_dir"]).resolve())
    return payload


def compute_config_hash(path: str | Path | None = None) -> str:
    config_path = Path(path) if path else CONFIG_PATH
    digest = hashlib.sha256()
    digest.update(config_path.read_bytes())
    return digest.hexdigest()


def validate_template_config(config: dict) -> list[str]:
    errors: list[str] = []
    source_dir = Path(config.get("source_dir") or "")
    if not source_dir.exists():
        errors.append(f"模板源目录不存在：{source_dir}")
    templates = config.get("templates") or []
    if len(templates) != 6:
        errors.append("第1章监管信息模板配置必须包含 6 个模板。")
    seen: set[str] = set()
    for template in templates:
        code = str(template.get("code") or "")
        if not code:
            errors.append("模板 code 不能为空。")
        elif code in seen:
            errors.append(f"模板 code 重复：{code}")
        seen.add(code)
        source_file = str(template.get("source_file") or "")
        output_name = str(template.get("output_name") or "")
        if not source_file:
            errors.append(f"模板 {code} 缺少 source_file。")
        elif source_dir.exists() and not (source_dir / source_file).exists():
            errors.append(f"模板源文件不存在：{source_file}")
        if not output_name:
            errors.append(f"模板 {code} 缺少 output_name。")
    return errors