"""
app/config.py
Runtime configuration loaded from environment variables with sensible defaults.
"""

from __future__ import annotations

import os
from dataclasses import dataclass, field


@dataclass
class Settings:
    # Server
    host: str = "0.0.0.0"
    http_port: int = 8000

    # Database
    db_path: str = "data/local_mcp.sqlite3"

    # Logging
    log_level: str = "INFO"

    # MCP / queue behaviour (runtime-editable values are stored in DB; these are defaults for first run)
    default_wait_seconds: int = 10
    default_empty_response: str = ""
    agent_stale_after_seconds: int = 30

    # MCP server name
    mcp_server_name: str = "local-mcp"

    # MCP transport — stateless=True means no session IDs, survives server restarts.
    # Set MCP_STATELESS=false to use stateful sessions (needed for multi-turn MCP flows).
    mcp_stateless: bool = True

    # Authentication — set API_TOKEN env var to enable; empty string disables auth entirely.
    api_token: str = ""


def _parse_bool(value: str, default: bool) -> bool:
    if value.lower() in ("1", "true", "yes", "on"):
        return True
    if value.lower() in ("0", "false", "no", "off"):
        return False
    return default


def load_settings() -> Settings:
    """Load settings from environment variables, falling back to defaults."""
    return Settings(
        host=os.getenv("HOST", "0.0.0.0"),
        http_port=int(os.getenv("HTTP_PORT", "8000")),
        db_path=os.getenv("DB_PATH", "data/local_mcp.sqlite3"),
        log_level=os.getenv("LOG_LEVEL", "INFO"),
        default_wait_seconds=int(os.getenv("DEFAULT_WAIT_SECONDS", "10")),
        default_empty_response=os.getenv("DEFAULT_EMPTY_RESPONSE", ""),
        agent_stale_after_seconds=int(os.getenv("AGENT_STALE_AFTER_SECONDS", "30")),
        mcp_server_name=os.getenv("MCP_SERVER_NAME", "local-mcp"),
        mcp_stateless=_parse_bool(os.getenv("MCP_STATELESS", "true"), default=True),
        api_token=os.getenv("API_TOKEN", ""),
    )


# Singleton – imported and used throughout the app
settings: Settings = load_settings()