import os
import os.path
import sys
from datetime import datetime
from PhotoAlbum import Photo, Album, PhotoAlbumEncoder
from CachePath import *
import json


class TreeWalker:
    def __init__(self, album_path, cache_path):
        self.album_path = os.path.abspath(
            album_path).decode(sys.getfilesystemencoding())
        self.cache_path = os.path.abspath(
            cache_path).decode(sys.getfilesystemencoding())
        set_cache_path_base(self.album_path)
        self.all_albums = list()
        self.all_photos = list()
        self.walk(self.album_path)
        self.big_lists()
        self.remove_stale()
        message("complete", "")

    def walk(self, path):
        next_level()
        if not os.access(path, os.R_OK | os.X_OK):
            message("access denied", os.path.basename(path))
            back_level()
            return None
        message("walking", os.path.basename(path))
        cache = os.path.join(self.cache_path, json_cache(path))
        cached = False
        cached_album = None
        if os.path.exists(cache):
            try:
                cached_album = Album.from_cache(cache)
                if file_mtime(path) <= file_mtime(cache):
                    message("full cache", os.path.basename(path))
                    cached = True
                    album = cached_album
                    for photo in album.photos:
                        self.all_photos.append(photo)
                else:
                    message("partial cache", os.path.basename(path))
            except KeyboardInterrupt:
                raise
            except:
                message("corrupt cache", os.path.basename(path))
                cached_album = None
        if not cached:
            album = Album(path)
        for entry in os.listdir(path):
            if entry[0] == '.':
                continue
            try:
                entry = entry.decode(sys.getfilesystemencoding())
            except KeyboardInterrupt:
                raise
            except:
                next_level()
                message("unicode error", entry.decode(
                    sys.getfilesystemencoding(), "replace"))
                back_level()
                continue
            entry = os.path.join(path, entry)
            if os.path.isdir(entry):
                next_walked_album = self.walk(entry)
                if next_walked_album is not None:
                    album.add_album(next_walked_album)
            elif not cached and os.path.isfile(entry):
                next_level()
                cache_hit = False
                if cached_album:
                    cached_photo = cached_album.photo_from_path(entry)
                    if (cached_photo and file_mtime(
                            entry) <= cached_photo.attributes["dateTimeFile"]):
                        cache_file = None
                        if "mediaType" in cached_photo.attributes:
                            if cached_photo.attributes["mediaType"] == "video":
                                # if video
                                cache_file = os.path.join(
                                    self.cache_path, video_cache(entry))
                            else:
                                # if image
                                cache_file = os.path.join(
                                    self.cache_path,
                                    image_cache(entry, 1024, False))
                        else:
                            # if image
                            cache_file = os.path.join(
                                self.cache_path,
                                image_cache(entry, 1024, False))

                        # at this point we have full path to cache image/video
                        # check if it actually exists
                        if os.path.exists(cache_file):
                            message("cache hit", os.path.basename(entry))
                            cache_hit = True
                            photo = cached_photo

                if not cache_hit:
                    message("metainfo", os.path.basename(entry))
                    photo = Photo(entry, self.cache_path)
                if photo.is_valid:
                    self.all_photos.append(photo)
                    album.add_photo(photo)
                else:
                    message("unreadable", os.path.basename(entry))
                back_level()
        if not album.empty:
            message("caching", os.path.basename(path))
            album.cache(self.cache_path)
            self.all_albums.append(album)
        else:
            message("empty", os.path.basename(path))
        back_level()
        return album

    def big_lists(self):
        photo_list = []
        self.all_photos.sort()
        for photo in self.all_photos:
            photo_list.append(photo.path)
        message("caching", "all photos path list")
        fp = open(os.path.join(self.cache_path, "all_photos.json"), 'w')
        json.dump(photo_list, fp, cls=PhotoAlbumEncoder)
        fp.close()

    def remove_stale(self):
        message("cleanup", "building stale list")
        all_cache_entries = {"all_photos.json": True,
                             "latest_photos.json": True}
        for album in self.all_albums:
            all_cache_entries[album.cache_path] = True
        for photo in self.all_photos:
            for entry in photo.image_caches:
                all_cache_entries[entry] = True
        message("cleanup", "searching for stale cache entries")
        for cache in os.listdir(self.cache_path):
            try:
                cache = cache.decode(sys.getfilesystemencoding())
            except KeyboardInterrupt:
                raise
            except:
                pass
            if cache not in all_cache_entries:
                message("cleanup", os.path.basename(cache))
                os.unlink(os.path.join(self.cache_path, cache))