from __future__ import annotations

import os
from pathlib import Path


def disk_usage(path: str) -> dict:
    usage = os.statvfs(path)
    total = usage.f_frsize * usage.f_blocks
    free = usage.f_frsize * usage.f_bavail
    used = total - free
    return {"total": total, "used": used, "free": free}


def drive_stats(config: dict) -> list[dict]:
    stats = []
    for drive in config.get("drives", []):
        path = Path(drive["path"])
        path.mkdir(parents=True, exist_ok=True)
        usage = disk_usage(str(path))
        stats.append({**drive, **usage})
    return stats


def find_existing_home(config: dict, title: str) -> str | None:
    normalized = title.lower()
    for drive in config.get("drives", []):
        root = Path(drive["path"])
        for folder in ("Movies", "Shows"):
            base = root / folder
            if not base.exists():
                continue
            for child in base.iterdir():
                if child.is_dir() and child.name.lower().startswith(normalized):
                    return str(root)
    return None


def choose_drive(config: dict, title: str) -> dict:
    existing = find_existing_home(config, title)
    if existing:
        for drive in config.get("drives", []):
            if drive["path"] == existing:
                return drive
    candidates = []
    for drive in drive_stats(config):
        min_free = int(drive.get("min_free_gb", 0)) * 1024**3
        if drive["free"] >= min_free:
            candidates.append(drive)
    if not candidates:
        raise RuntimeError("No media drive has the configured minimum free space")
    return max(candidates, key=lambda d: d["free"])