import logging
from pathlib import Path

from django.conf import settings
from django.utils.text import slugify

from ..models import Camera


logger = logging.getLogger('camlaps')


def _storage_root() -> Path:
    storage_path = getattr(settings, 'STORAGE_PATH', None)
    if storage_path is None:
        return Path('/app/storage')
    return Path(storage_path)


def generate_unique_camera_slug(directory_name: str, storage_path: str) -> str:
    base_slug = (slugify(directory_name) or f'camera-{directory_name.lower()}')[:70]
    slug = base_slug
    suffix = 1

    while Camera.objects.filter(slug=slug).exclude(storage_path=storage_path).exists():
        suffix_part = f'-{suffix}'
        slug = f"{base_slug[:80 - len(suffix_part)]}{suffix_part}"
        suffix += 1

    return slug


def is_storage_available() -> bool:
    logger.info('cameras:storage_available:start')
    try:
        root = _storage_root()
        ok = root.exists() and root.is_dir()
        logger.info('cameras:storage_available:done ok=%s', ok)
        return ok
    except Exception:
        logger.exception('cameras:storage_available:error')
        raise


def list_active_cameras() -> list[Camera]:
    logger.info('cameras:list_active:start')
    try:
        cameras = list(Camera.objects.filter(is_active=True).order_by('name'))
        logger.info('cameras:list_active:done count=%s', len(cameras))
        return cameras
    except Exception:
        logger.exception('cameras:list_active:error')
        raise


def get_camera_lastsnap_path(camera: Camera) -> Path | None:
    logger.info('cameras:lastsnap_path:start camera_id=%s', camera.id)
    try:
        root = _storage_root().resolve()
        candidate = (root / camera.storage_path / 'lastsnap.jpg').resolve()

        if candidate != root and root not in candidate.parents:
            logger.info('cameras:lastsnap_path:done camera_id=%s found=false', camera.id)
            return None

        if not candidate.exists() or not candidate.is_file():
            logger.info('cameras:lastsnap_path:done camera_id=%s found=false', camera.id)
            return None

        logger.info('cameras:lastsnap_path:done camera_id=%s found=true', camera.id)
        return candidate
    except Exception:
        logger.exception('cameras:lastsnap_path:error camera_id=%s', camera.id)
        raise


def discover_camera_candidates() -> list[dict[str, str]]:
    logger.info('cameras:discover_candidates:start')
    try:
        root = _storage_root()
        if not root.exists() or not root.is_dir():
            logger.info('cameras:discover_candidates:done count=0')
            return []

        existing_paths = set(Camera.objects.values_list('storage_path', flat=True))
        dirs = [p for p in root.iterdir() if p.is_dir() and not p.name.startswith('.') and p.name != 'timelapses']

        candidates = []
        for directory in sorted(dirs, key=lambda d: d.name.lower()):
            storage_path = directory.name
            if storage_path in existing_paths:
                continue
            candidates.append({'name': directory.name, 'storage_path': storage_path})

        logger.info('cameras:discover_candidates:done count=%s', len(candidates))
        return candidates
    except Exception:
        logger.exception('cameras:discover_candidates:error')
        raise


def create_cameras_from_candidates(selected_storage_paths: list[str]) -> int:
    logger.info('cameras:create_from_candidates:start count=%s', len(selected_storage_paths))
    try:
        created = 0
        for storage_path in selected_storage_paths:
            path = storage_path.strip()
            if not path:
                continue

            slug = generate_unique_camera_slug(path, path)
            _, was_created = Camera.objects.get_or_create(
                storage_path=path,
                defaults={'name': path, 'slug': slug, 'is_active': True},
            )
            if was_created:
                created += 1

        logger.info('cameras:create_from_candidates:done created=%s', created)
        return created
    except Exception:
        logger.exception('cameras:create_from_candidates:error')
        raise