"""Configuration module — loads settings from .env file or environment variables."""

import os
from pathlib import Path
from dotenv import load_dotenv

# Load .env from project root
load_dotenv(Path(__file__).parent / ".env")


class Config:
    """Bridge configuration."""

    # Discord
    DISCORD_TOKEN: str = os.getenv("DISCORD_TOKEN", "")
    DISCORD_GUILD_ID: int = int(os.getenv("DISCORD_GUILD_ID") or "0")

    # Antigravity Brain path
    # NOTE: os.getenv returns "" (not None) when .env has BRAIN_PATH= (empty value).
    # Path("") resolves to "." (CWD), which is WRONG. Use `or` to handle both None and "".
    BRAIN_PATH: Path = Path(
        os.getenv("BRAIN_PATH") or os.path.expanduser("~/.gemini/antigravity/brain")
    )

    # Watcher settings
    DEBOUNCE_SECONDS: float = float(os.getenv("DEBOUNCE_SECONDS", "5"))

    # Files to monitor within each conversation directory (PRIMARY ONLY)
    WATCHED_FILES: set = {
        "task.md",
        "implementation_plan.md",
        "walkthrough.md",
    }

    # Discord message limits
    DISCORD_MSG_LIMIT: int = 2000
    DISCORD_EMBED_DESC_LIMIT: int = 4096

    # Channel naming
    CHANNEL_PREFIX: str = "AG"
    PROJECT_NAME: str = os.getenv("PROJECT_NAME", "gravity_control")

    # Bot mode: 'local' (file-based bridge) or 'remote' (HTTP polling — future)
    BOT_MODE: str = os.getenv("BOT_MODE", "local")
    REMOTE_BRIDGE_URL: str = os.getenv("REMOTE_BRIDGE_URL", "")

    @classmethod
    def validate(cls) -> list[str]:
        """Return list of configuration errors."""
        errors = []
        if not cls.DISCORD_TOKEN:
            errors.append("DISCORD_TOKEN is not set")
        if not cls.DISCORD_GUILD_ID:
            errors.append("DISCORD_GUILD_ID is not set")
        # Gateway mode doesn't need local BRAIN_PATH
        if cls.BOT_MODE != 'gateway' and not cls.BRAIN_PATH.exists():
            errors.append(f"BRAIN_PATH does not exist: {cls.BRAIN_PATH}")
        return errors