from __future__ import annotations

import configparser
import os
from dataclasses import dataclass

from sapcli.exceptions import ConfigError


@dataclass(frozen=True)
class SAPConfig:
    host: str
    client: str
    user: str
    password: str

    def __post_init__(self):
        missing = []
        if not self.host:
            missing.append("host")
        if not self.user:
            missing.append("user")
        if not self.password:
            missing.append("password")
        if missing:
            raise ConfigError(
                f"配置缺失: {', '.join(missing)}. "
                f"请设置环境变量或配置文件 (config.ini)"
            )


def list_profiles(config_path: str | None = None) -> list[str]:
    """列出配置文件中所有可用的 profile（section 名称）。"""
    cfg = configparser.ConfigParser()
    path = config_path or _find_config_file()
    if path:
        cfg.read(path, encoding="utf-8")
    return cfg.sections()


def _find_config_file() -> str | None:
    """按搜索路径查找 config.ini。"""
    search_paths: list[str] = []
    script_dir = os.path.dirname(os.path.abspath(__file__))
    project_root = os.path.dirname(script_dir)
    search_paths.append(os.path.join(os.getcwd(), "config.ini"))
    search_paths.append(os.path.join(project_root, "config.ini"))
    for p in search_paths:
        if os.path.isfile(p):
            return p
    return None


def load_config(
    config_path: str | None = None,
    profile: str | None = None,
) -> tuple[SAPConfig, str | None]:
    cfg = configparser.ConfigParser()
    search_paths: list[str] = []

    if config_path:
        search_paths.append(config_path)

    script_dir = os.path.dirname(os.path.abspath(__file__))
    project_root = os.path.dirname(script_dir)
    search_paths.append(os.path.join(os.getcwd(), "config.ini"))
    search_paths.append(os.path.join(project_root, "config.ini"))

    loaded_from = None
    for p in search_paths:
        if os.path.isfile(p):
            cfg.read(p, encoding="utf-8")
            loaded_from = p
            break

    # profile 参数决定读哪个 section，默认 SAP
    section = profile or "SAP"
    sap = cfg[section] if cfg.has_section(section) else {}

    host = os.environ.get("SAP_HOST", sap.get("host", ""))
    client = os.environ.get("SAP_CLIENT", sap.get("client", "100"))
    user = os.environ.get("SAP_USER", sap.get("user", ""))
    config_password = sap.get("password", "")
    env_password = os.environ.get("SAP_PASSWORD", "")

    # 密码优先级: 环境变量 > keyring > config.ini
    from sapcli.password import resolve_password
    password = resolve_password(host, client, user, config_password, env_password)

    return SAPConfig(
        host=host,
        client=client,
        user=user,
        password=password,
    ), loaded_from