/**
 * VideoCharm - Local Storage Management
 * Handles all local storage operations for history and favorites
 */

const StorageManager = (function() {
    // Storage keys
    const KEYS = {
        HISTORY: 'videocharm_history',
        FAVORITES: 'videocharm_favorites',
        LIKES: 'videocharm_likes',
        VIEWS: 'videocharm_views'
    };
    
    // Maximum storage age (7 days in milliseconds)
    const MAX_HISTORY_AGE = 7 * 24 * 60 * 60 * 1000;
    
    /**
     * Initialize storage with default values if not exists
     */
    function initStorage() {
        if (!localStorage.getItem(KEYS.HISTORY)) {
            localStorage.setItem(KEYS.HISTORY, JSON.stringify([]));
        }
        
        if (!localStorage.getItem(KEYS.FAVORITES)) {
            localStorage.setItem(KEYS.FAVORITES, JSON.stringify([]));
        }
        
        if (!localStorage.getItem(KEYS.LIKES)) {
            localStorage.setItem(KEYS.LIKES, JSON.stringify([]));
        }
        
        if (!localStorage.getItem(KEYS.VIEWS)) {
            localStorage.setItem(KEYS.VIEWS, JSON.stringify(0));
        }
        
        // Clean up old history entries
        cleanupHistory();
    }
    
    /**
     * Remove history items older than MAX_HISTORY_AGE
     */
    function cleanupHistory() {
        const history = getHistory();
        const now = new Date().getTime();
        
        const filteredHistory = history.filter(item => {
            return (now - item.timestamp) < MAX_HISTORY_AGE;
        });
        
        if (filteredHistory.length !== history.length) {
            localStorage.setItem(KEYS.HISTORY, JSON.stringify(filteredHistory));
        }
    }
    
    /**
     * Get all history items
     * @returns {Array} History items
     */
    function getHistory() {
        try {
            return JSON.parse(localStorage.getItem(KEYS.HISTORY)) || [];
        } catch (e) {
            console.error('Error parsing history from localStorage:', e);
            return [];
        }
    }
    
    /**
     * Get all favorites
     * @returns {Array} Favorite items
     */
    function getFavorites() {
        try {
            return JSON.parse(localStorage.getItem(KEYS.FAVORITES)) || [];
        } catch (e) {
            console.error('Error parsing favorites from localStorage:', e);
            return [];
        }
    }
    
    /**
     * Get all liked video IDs
     * @returns {Array} Liked video IDs
     */
    function getLikes() {
        try {
            return JSON.parse(localStorage.getItem(KEYS.LIKES)) || [];
        } catch (e) {
            console.error('Error parsing likes from localStorage:', e);
            return [];
        }
    }
    
    /**
     * Get view count
     * @returns {Number} Total view count
     */
    function getViews() {
        try {
            return parseInt(JSON.parse(localStorage.getItem(KEYS.VIEWS))) || 0;
        } catch (e) {
            console.error('Error parsing views from localStorage:', e);
            return 0;
        }
    }
    
    /**
     * Add a video to history
     * @param {Object} video Video object to add
     */
    function addToHistory(video) {
        if (!video || !video.id || !video.url) return;
        
        const history = getHistory();
        
        // Check if video already exists in history
        const existingIndex = history.findIndex(item => item.id === video.id);
        
        if (existingIndex !== -1) {
            // Update timestamp of existing item
            history[existingIndex].timestamp = new Date().getTime();
            // Update thumbnail if available
            if (video.thumbnail) {
                history[existingIndex].thumbnail = video.thumbnail;
            }
        } else {
            // Create simplified record for storage
            const historyItem = {
                id: video.id,
                url: video.url,
                title: video.title || '精彩视频',
                timestamp: new Date().getTime(),
                duration: video.duration || 0,
                thumbnail: video.thumbnail || null
            };
            
            // Add to beginning of array
            history.unshift(historyItem);
        }
        
        // Save updated history
        localStorage.setItem(KEYS.HISTORY, JSON.stringify(history));
        
        // Increment view count
        incrementViews();
    }
    
    /**
     * Toggle favorite status for a video
     * @param {Object} video Video object
     * @returns {Boolean} New favorite status
     */
    function toggleFavorite(video) {
        if (!video || !video.id) return false;
        
        const favorites = getFavorites();
        const existingIndex = favorites.findIndex(item => item.id === video.id);
        
        if (existingIndex !== -1) {
            // Remove from favorites
            favorites.splice(existingIndex, 1);
            localStorage.setItem(KEYS.FAVORITES, JSON.stringify(favorites));
            return false;
        } else {
            // Create simplified record for storage
            const favoriteItem = {
                id: video.id,
                url: video.url,
                title: video.title || '精彩视频',
                timestamp: new Date().getTime(),
                duration: video.duration || 0,
                thumbnail: video.thumbnail || null
            };
            
            // Add to favorites
            favorites.unshift(favoriteItem);
            localStorage.setItem(KEYS.FAVORITES, JSON.stringify(favorites));
            return true;
        }
    }
    
    /**
     * Check if a video is favorited
     * @param {String} videoId Video ID to check
     * @returns {Boolean} Whether video is favorited
     */
    function isFavorite(videoId) {
        if (!videoId) return false;
        
        const favorites = getFavorites();
        return favorites.some(item => item.id === videoId);
    }
    
    /**
    * Toggle like status for a video
    * @param {String} videoId Video ID
    * @returns {Boolean} New like status
    */
   function toggleLike(videoId) {
    if (!videoId) return false;
    
    const likes = getLikes();
    const index = likes.indexOf(videoId);
    
    if (index !== -1) {
        // Remove like
        likes.splice(index, 1);
        localStorage.setItem(KEYS.LIKES, JSON.stringify(likes));
        return false;
    } else {
        // Add like
        likes.push(videoId);
        localStorage.setItem(KEYS.LIKES, JSON.stringify(likes));
        return true;
    }
}

/**
 * Check if a video is liked
 * @param {String} videoId Video ID to check
 * @returns {Boolean} Whether video is liked
 */
function isLiked(videoId) {
    if (!videoId) return false;
    
    const likes = getLikes();
    return likes.includes(videoId);
}

/**
 * Increment view count
 */
function incrementViews() {
    const views = getViews();
    localStorage.setItem(KEYS.VIEWS, JSON.stringify(views + 1));
}

/**
 * Clear all history
 */
function clearHistory() {
    localStorage.setItem(KEYS.HISTORY, JSON.stringify([]));
}

/**
 * Clear all favorites
 */
function clearFavorites() {
    localStorage.setItem(KEYS.FAVORITES, JSON.stringify([]));
}

// Public API
return {
    init: initStorage,
    getHistory: getHistory,
    getFavorites: getFavorites,
    getLikes: getLikes,
    getViews: getViews,
    addToHistory: addToHistory,
    toggleFavorite: toggleFavorite,
    isFavorite: isFavorite,
    toggleLike: toggleLike,
    isLiked: isLiked,
    clearHistory: clearHistory,
    clearFavorites: clearFavorites
};
})();