import os
import shutil
from datetime import datetime, timedelta, timezone

from sqlalchemy import select
from sqlalchemy.orm import Session

from app.config import settings
from app.models.export_file import ExportFile
from app.models.recording import Recording
from app.models.transcription import Transcription


def get_disk_usage() -> dict:
    upload_size = _dir_size(settings.upload_dir)
    export_size = _dir_size(settings.export_dir)
    return {
        "uploads_bytes": upload_size,
        "exports_bytes": export_size,
        "total_bytes": upload_size + export_size,
        "total_gb": round((upload_size + export_size) / (1024 ** 3), 2),
    }


def _dir_size(path: str) -> int:
    total = 0
    if not os.path.exists(path):
        return 0
    for dirpath, _, filenames in os.walk(path):
        for f in filenames:
            fp = os.path.join(dirpath, f)
            total += os.path.getsize(fp)
    return total


def cleanup_old_data(db: Session, retention_days: int | None = None):
    days = retention_days or settings.retention_days
    cutoff = datetime.now(timezone.utc) - timedelta(days=days)

    old_recordings = db.execute(
        select(Recording).where(Recording.created_at < cutoff)
    ).scalars().all()

    deleted_count = 0
    for recording in old_recordings:
        if os.path.exists(recording.file_path):
            os.remove(recording.file_path)
        if recording.transcription:
            for protocol in recording.transcription.protocols:
                for export_file in protocol.export_files:
                    if os.path.exists(export_file.file_path):
                        os.remove(export_file.file_path)
        db.delete(recording)
        deleted_count += 1

    db.commit()
    return {"deleted_recordings": deleted_count}