"""Configuration and common utilities for daily summary."""

import os
from datetime import datetime, timedelta, timezone
from pathlib import Path
from typing import Optional


def get_vault_path(cli_vault: Optional[str] = None) -> Path:
    """Resolve the Obsidian vault path from CLI arg, env var, or default locations."""
    if cli_vault:
        vault = Path(cli_vault).expanduser().resolve()
        if not vault.exists():
            raise FileNotFoundError(f"Vault path does not exist: {vault}")
        return vault

    env_vault = os.environ.get("OBSIDIAN_VAULT")
    if env_vault:
        vault = Path(env_vault).expanduser().resolve()
        if vault.exists():
            return vault

    obsidian_dir = Path.home() / "Obsidian"
    if obsidian_dir.exists():
        vaults = [d for d in obsidian_dir.iterdir() if d.is_dir()]
        if len(vaults) == 1:
            return vaults[0]
        elif len(vaults) > 1:
            raise RuntimeError(
                f"Multiple vaults found in {obsidian_dir}. "
                "Set OBSIDIAN_VAULT or use --vault."
            )

    raise RuntimeError(
        "Could not determine Obsidian vault path. "
        "Use --vault or set OBSIDIAN_VAULT environment variable."
    )


def get_daily_notes_folder(vault_path: Path) -> Path:
    """Return the daily notes folder, defaulting to 'Daily Notes'."""
    folder = os.environ.get("OBSIDIAN_DAILY_FOLDER", "Daily Notes")
    return vault_path / folder


def date_range(dt: datetime) -> tuple[int, int]:
    """Return Unix timestamp range for the given datetime's date (start, end)."""
    start = datetime(dt.year, dt.month, dt.day, tzinfo=dt.tzinfo or timezone.utc)
    end = start + timedelta(days=1)
    return int(start.timestamp()), int(end.timestamp())


def format_duration(seconds: int) -> str:
    """Format seconds as 'Xh Ym' or 'Ym'."""
    if seconds < 60:
        return f"{seconds}s"
    hours, remainder = divmod(seconds, 3600)
    minutes = remainder // 60
    if hours:
        return f"{hours}h {minutes}m"
    return f"{minutes}m"