from __future__ import annotations

import os
from dataclasses import dataclass
from pathlib import Path
from typing import Optional

try:
    from dotenv import load_dotenv
except Exception:  # pragma: no cover
    load_dotenv = None


@dataclass(slots=True)
class CoreAgentConfig:
    model: str
    api_key: Optional[str]
    base_url: Optional[str]
    timeout: float = 120.0
    temperature: float = 0.2
    max_iterations: int = 12
    user_name: str = "User"
    agent_name: str = "MeetingAgent"


def load_core_agent_env(env_dir: str | Path | None = None) -> Optional[Path]:
    candidates = []
    if env_dir:
        candidates.append(Path(env_dir) / ".env")
    candidates.append(Path.cwd() / ".env")
    for path in candidates:
        if not path.exists():
            continue
        if load_dotenv is not None:
            load_dotenv(path, override=False)
        else:
            _load_env_without_dependency(path)
        return path
    return None


def apply_compat_env_aliases() -> None:
    if not os.getenv("OPENAI_API_KEY") and os.getenv("API_KEY"):
        os.environ["OPENAI_API_KEY"] = os.environ["API_KEY"]
    if not os.getenv("OPENAI_BASE_URL") and os.getenv("BASE_URL"):
        os.environ["OPENAI_BASE_URL"] = os.environ["BASE_URL"]
    if not os.getenv("CORE_AGENT_MODEL") and os.getenv("MODEL_NAME"):
        os.environ["CORE_AGENT_MODEL"] = os.environ["MODEL_NAME"]


def build_core_agent_config() -> CoreAgentConfig:
    return CoreAgentConfig(
        model=os.getenv("CORE_AGENT_MODEL") or os.getenv("MODEL_NAME") or os.getenv("MODEL") or "",
        api_key=os.getenv("OPENAI_API_KEY") or os.getenv("API_KEY"),
        base_url=os.getenv("OPENAI_BASE_URL") or os.getenv("BASE_URL"),
        timeout=float(os.getenv("OPENAI_TIMEOUT", "120")),
        temperature=float(os.getenv("OPENAI_TEMPERATURE", "0.2")),
        max_iterations=int(os.getenv("CORE_AGENT_MAX_ITERATIONS", "12")),
        user_name=os.getenv("USER_NAME", "User"),
        agent_name=os.getenv("AGENT_NAME", "MeetingAgent"),
    )


def require_model_config(config: CoreAgentConfig) -> None:
    missing = []
    if _is_missing_or_placeholder(config.api_key):
        missing.append("OPENAI_API_KEY")
    if _is_missing_or_placeholder(config.base_url):
        missing.append("OPENAI_BASE_URL")
    if _is_missing_or_placeholder(config.model):
        missing.append("MODEL_NAME or CORE_AGENT_MODEL")
    if missing:
        joined = ", ".join(missing)
        raise RuntimeError(
            "缺少大模型配置：" + joined + "。请复制 .env.example 为 .env，并填写 OpenAI-compatible API 配置；"
            "如果只想本地演示工具流程，请加 --offline。"
        )


def _load_env_without_dependency(path: Path) -> None:
    for raw_line in path.read_text(encoding="utf-8").splitlines():
        line = raw_line.strip()
        if not line or line.startswith("#") or "=" not in line:
            continue
        key, value = line.split("=", 1)
        key = key.strip()
        value = value.strip().strip('"').strip("'")
        if key and key not in os.environ:
            os.environ[key] = value


def _is_missing_or_placeholder(value: Optional[str]) -> bool:
    if value is None or not str(value).strip():
        return True
    normalized = str(value).strip().lower()
    placeholders = {
        "your-api-key-here",
        "your-base-url-here",
        "your-model-name-here",
        "sk-xxx",
        "xxx",
        "changeme",
    }
    return normalized in placeholders or normalized.startswith("your-")