from __future__ import annotations

import os
from dataclasses import dataclass
from pathlib import Path


def load_env_file(path: Path) -> None:
    if not path.exists():
        return
    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)
        os.environ.setdefault(key.strip(), value.strip())


@dataclass(slots=True)
class ServerConfig:
    host: str
    port: int
    model: str
    workspace_root: Path
    session_dir: Path
    system_prompt: str
    max_tool_rounds: int

    @classmethod
    def load(cls) -> "ServerConfig":
        base_dir = Path(__file__).resolve().parent
        load_env_file(base_dir / ".env")
        workspace_root = Path(
            os.environ.get("NEW_QWEN_WORKSPACE_ROOT", str(Path.cwd()))
        ).expanduser()
        session_dir = Path(
            os.environ.get(
                "NEW_QWEN_SESSION_DIR",
                str(base_dir.parent / ".new-qwen" / "sessions"),
            )
        ).expanduser()
        return cls(
            host=os.environ.get("NEW_QWEN_HOST", "127.0.0.1"),
            port=int(os.environ.get("NEW_QWEN_PORT", "8080")),
            model=os.environ.get("NEW_QWEN_MODEL", "qwen3.6-plus"),
            workspace_root=workspace_root.resolve(),
            session_dir=session_dir.resolve(),
            system_prompt=os.environ.get("NEW_QWEN_SYSTEM_PROMPT", "").strip(),
            max_tool_rounds=int(os.environ.get("NEW_QWEN_MAX_TOOL_ROUNDS", "8")),
        )