/**
 * ContentSecurityManager
 * Client-side content security filtering for WeChat mini game.
 *
 * Features:
 * - Local sensitive word filtering (50ms target)
 * - Remote word list fetching with 24-hour local cache
 * - Built-in fallback word list when remote fetch fails
 * - Incremental word list updates without blocking ongoing checks
 * - Integration with server-side msgSecCheck/imgSecCheck APIs
 */

// ============================================================
// Configuration
// ============================================================
const CACHE_KEY = 'content_security_word_cache';
const CACHE_VERSION_KEY = 'content_security_word_version';
const CACHE_TIMESTAMP_KEY = 'content_security_word_timestamp';
const CACHE_VALIDITY_MS = 24 * 60 * 60 * 1000; // 24 hours
const SERVER_BASE_URL = ''; // Will use relative URL or configured server URL
const DEFAULT_GAME_ID = 'tankwar'; // Default game identifier for multi-tenant isolation

// Scene mapping (must match server-side)
const SCENE = {
  NICKNAME: 1,
  CHAT: 2,
  SIGNATURE: 3,
  DESCRIPTION: 4,
};

// Report reasons
const REPORT_REASONS = {
  POLITICS: 'politics',
  PORNOGRAPHY: 'pornography',
  GAMBLING: 'gambling',
  OTHER: 'other',
};

// Report reason display labels
const REPORT_REASON_LABELS = {
  politics: '政治有害',
  pornography: '色情低俗',
  gambling: '赌博诈骗',
  other: '其他',
};

// ============================================================
// Built-in Fallback Sensitive Word List
// This is used when the remote word list is unavailable.
// ============================================================
const FALLBACK_WORDS = [
  // Politics
  '颠覆国家', '推翻政权', '分裂国家', '恐怖组织', '极端主义',
  '法轮', '法轮功', '台独', '藏独', '疆独',
  // Pornography
  '色情', '淫秽', '裸体', '卖淫', '嫖娼',
  '约炮', '援交', '一夜情', '黄色视频',
  // Gambling
  '赌博', '赌场', '下注', '博彩', '六合彩',
  '时时彩', '赌球', '百家乐', '老虎机',
  // Violence
  '杀人', '砍人', '捅死', '自制炸弹', '血腥屠杀',
  // Abuse
  '傻逼', '操你', '妈的', '草泥马', '脑残',
  '贱人', '狗日的', '废物', '滚蛋', '王八蛋',
  // Fraud
  '代开发票', '传销', '诈骗', '洗钱',
  // Other
  '代孕', '毒品', '吸毒', '走私', '枪支',
];

class ContentSecurityManager {
  constructor() {
    /** @type {string[]} Active sensitive word list */
    this._words = [];

    /** @type {string} Current word list version */
    this._version = '';

    /** @type {boolean} Whether the manager is initialized */
    this._initialized = false;

    /** @type {boolean} Whether an update is in progress */
    this._updating = false;

    /** @type {string} Server base URL for API calls */
    this._serverUrl = '';

    /** @type {string} Game identifier for multi-tenant isolation */
    this._gameId = DEFAULT_GAME_ID;
  }

  /**
   * Initialize the manager: load cached words, then fetch latest.
   * @param {object} [options]
   * @param {string} [options.serverUrl] - Server base URL
   * @returns {Promise<void>}
   */
  async init(options = {}) {
    this._serverUrl = options.serverUrl || '';
    this._gameId = options.gameId || DEFAULT_GAME_ID;

    // Try to load from cache first
    this._loadFromCache();

    // If no cached words, use fallback
    if (this._words.length === 0) {
      this._words = [...FALLBACK_WORDS];
      console.log('[ContentSecurity] Using fallback word list (' + this._words.length + ' words)');
    }

    this._initialized = true;

    // Fetch latest words from server (non-blocking)
    this.fetchWordList();

    console.log('[ContentSecurity] Initialized with ' + this._words.length + ' words');
  }

  /**
   * Check text content against local sensitive words.
   * Must complete within 50ms.
   * @param {string} content - Text to check
   * @returns {{ hasViolation: boolean, matchedWords: string[] }}
   */
  checkLocalText(content) {
    if (!content || typeof content !== 'string') {
      return { hasViolation: false, matchedWords: [] };
    }

    const startTime = Date.now();
    const lowerContent = content.toLowerCase();
    const matchedWords = [];

    for (let i = 0; i < this._words.length; i++) {
      const word = this._words[i];
      if (word && lowerContent.includes(word.toLowerCase())) {
        matchedWords.push(word);
        // Early exit if we find violations (performance optimization)
        if (matchedWords.length >= 3) break;
      }
    }

    const duration = Date.now() - startTime;
    if (duration > 50) {
      console.warn('[ContentSecurity] Local check took ' + duration + 'ms (target: 50ms)');
    }

    return {
      hasViolation: matchedWords.length > 0,
      matchedWords,
    };
  }

  /**
   * Check text content via server-side API (msgSecCheck).
   * @param {string} openid - User's openid
   * @param {string} content - Text to check
   * @param {number} scene - Scene value (1=nickname, 2=chat, 3=signature, 4=description)
   * @returns {Promise<{pass: boolean, errcode: number, errmsg: string, suggest: string, label: number}>}
   */
  async checkTextContent(openid, content, scene) {
    if (!this._serverUrl) {
      return {
        pass: true,
        errcode: 0,
        errmsg: 'ok',
        suggest: 'pass',
        label: 100,
      };
    }
    try {
      const res = await this._request({
        url: `${this._serverUrl}/api/content/check-text`,
        method: 'POST',
        data: { openid, content, scene },
      });
      return res;
    } catch (err) {
      console.error('[ContentSecurity] checkTextContent error:', err && (err.message || err.errMsg) || 'unknown');
      return {
        pass: false,
        errcode: -1,
        errmsg: '审核服务暂时不可用，请稍后再试',
        suggest: 'risky',
        label: 100,
      };
    }
  }

  /**
   * Check image content via server-side API (imgSecCheck).
   * @param {string} filePath - Local temporary file path of the image
   * @param {string} openid - User's openid
   * @returns {Promise<{pass: boolean, errcode: number, errmsg: string}>}
   */
  async checkImageContent(filePath, openid) {
    if (!this._serverUrl) {
      return { pass: true, errcode: 0, errmsg: 'ok' };
    }
    try {
      const res = await this._uploadImage(filePath, openid);
      return res;
    } catch (err) {
      console.error('[ContentSecurity] checkImageContent error:', err && (err.message || err.errMsg) || 'unknown');
      return {
        pass: false,
        errcode: -1,
        errmsg: '审核服务暂时不可用，请稍后再试',
      };
    }
  }

  /**
   * Fetch sensitive word list from server with cache validation.
   * Non-blocking: does not interfere with ongoing checks.
   * @returns {Promise<boolean>}
   */
  async fetchWordList() {
    if (this._updating) return false;
    if (!this._serverUrl) return false;
    this._updating = true;

    try {
      const res = await this._request({
        url: `${this._serverUrl}/api/content/sensitive-words`,
        method: 'GET',
        data: { version: this._version },
      });

      if (res.updated && res.words) {
        // Incremental update: replace word list atomically
        this._words = res.words;
        this._version = res.version;

        // Cache locally
        this._saveToCache();

        console.log('[ContentSecurity] Word list updated: ' + this._words.length + ' words, version: ' + this._version);
      }

      this._updating = false;
      return true;
    } catch (err) {
      console.error('[ContentSecurity] fetchWordList error:', err && (err.message || err.errMsg) || 'unknown');
      this._updating = false;
      return false;
    }
  }

  /**
   * Check if user is muted.
   * @param {string} openid
   * @returns {Promise<{isMuted: boolean, remainingMs: number, remainingText: string}>}
   */
  async getMuteStatus(openid) {
    if (!this._serverUrl) {
      return { isMuted: false, remainingMs: 0, remainingText: '' };
    }
    try {
      const res = await this._request({
        url: `${this._serverUrl}/api/content/user/mute-status`,
        method: 'GET',
        data: { openid },
      });
      return res;
    } catch (err) {
      console.error('[ContentSecurity] getMuteStatus error:', err && (err.message || err.errMsg) || 'unknown');
      return { isMuted: false, remainingMs: 0, remainingText: '' };
    }
  }

  /**
   * Submit a content report.
   * @param {object} entry
   * @param {string} entry.contentId - Unique content identifier
   * @param {string} entry.targetUserId - Content author's user ID
   * @param {string} entry.contentType - Content type ('chat', 'nickname', 'signature', 'description', 'avatar')
   * @param {string} entry.contentSummary - Content summary
   * @param {string} entry.reporterId - Reporter's user ID
   * @param {string} entry.reason - Report reason
   * @returns {Promise<{success: boolean, message: string}>}
   */
  async submitReport(entry) {
    if (!this._serverUrl) {
      return { success: false, message: '举报功能暂不可用' };
    }
    try {
      const res = await this._request({
        url: `${this._serverUrl}/api/content/report`,
        method: 'POST',
        data: entry,
      });
      return res;
    } catch (err) {
      console.error('[ContentSecurity] submitReport error:', err && (err.message || err.errMsg) || 'unknown');
      return { success: false, message: '举报提交失败，请稍后再试' };
    }
  }

  /**
   * Full text check: local check first, then server-side if local passes.
   * @param {string} openid
   * @param {string} content
   * @param {number} scene
   * @returns {Promise<{pass: boolean, localViolation: boolean, serverResult: object|null, errorMessage: string}>}
   */
  async fullTextCheck(openid, content, scene) {
    // Step 1: Local sensitive word check (fast)
    const localResult = this.checkLocalText(content);
    if (localResult.hasViolation) {
      return {
        pass: false,
        localViolation: true,
        serverResult: null,
        errorMessage: this._getErrorMessage({ suggest: 'risky' }, scene),
      };
    }

    // Step 2: Check mute status (for nickname/signature/description scenes)
    if (scene === SCENE.NICKNAME || scene === SCENE.SIGNATURE || scene === SCENE.DESCRIPTION) {
      const muteStatus = await this.getMuteStatus(openid);
      if (muteStatus.isMuted) {
        return {
          pass: false,
          localViolation: false,
          serverResult: null,
          errorMessage: '由于违规行为，您暂无法修改个人信息',
        };
      }
    }

    // Step 3: Server-side msgSecCheck
    const serverResult = await this.checkTextContent(openid, content, scene);
    if (!serverResult.pass) {
      return {
        pass: false,
        localViolation: false,
        serverResult,
        errorMessage: this._getErrorMessage(serverResult, scene),
      };
    }

    return {
      pass: true,
      localViolation: false,
      serverResult,
      errorMessage: '',
    };
  }

  /**
   * Get appropriate error message based on scene and result.
   * @param {object} result
   * @param {number} scene
   * @returns {string}
   */
  _getErrorMessage(result, scene) {
    if (scene === SCENE.NICKNAME) {
      return '昵称包含违规内容，请重新输入';
    }
    if (scene === SCENE.CHAT) {
      return '消息发送失败：内容违规';
    }
    if (scene === SCENE.SIGNATURE || scene === SCENE.DESCRIPTION) {
      return '内容包含违规信息，请修改';
    }
    return '内容违规，请修改';
  }

  /**
   * Make an HTTP request using wx.request.
   * @param {object} options
   * @returns {Promise<object>}
   */
  _request(options) {
    return new Promise((resolve, reject) => {
      const header = Object.assign({}, options.header || { 'content-type': 'application/json' });
      // Add X-Game-Id header for multi-tenant isolation
      if (this._gameId) {
        header['X-Game-Id'] = this._gameId;
      }
      wx.request({
        url: options.url,
        method: options.method || 'GET',
        data: options.data || {},
        header,
        success: (res) => {
          if (res.statusCode >= 200 && res.statusCode < 300) {
            resolve(res.data);
          } else {
            reject(new Error(`HTTP ${res.statusCode}`));
          }
        },
        fail: (err) => {
          reject(err);
        },
      });
    });
  }

  /**
   * Upload image for security check using wx.uploadFile.
   * @param {string} filePath - Local file path
   * @param {string} openid - User openid
   * @returns {Promise<object>}
   */
  _uploadImage(filePath, openid) {
    return new Promise((resolve, reject) => {
      const header = {};
      if (this._gameId) {
        header['X-Game-Id'] = this._gameId;
      }
      wx.uploadFile({
        url: `${this._serverUrl}/api/content/check-image`,
        filePath,
        name: 'image',
        formData: { openid },
        header,
        success: (res) => {
          if (res.statusCode >= 200 && res.statusCode < 300) {
            try {
              const data = JSON.parse(res.data);
              resolve(data);
            } catch (e) {
              reject(new Error('Invalid response'));
            }
          } else {
            reject(new Error(`HTTP ${res.statusCode}`));
          }
        },
        fail: (err) => {
          reject(err);
        },
      });
    });
  }

  /**
   * Load word list from local cache.
   */
  _loadFromCache() {
    try {
      const timestamp = wx.getStorageSync(CACHE_TIMESTAMP_KEY);
      const version = wx.getStorageSync(CACHE_VERSION_KEY);
      const words = wx.getStorageSync(CACHE_KEY);

      if (timestamp && version && words && Array.isArray(words)) {
        // Check if cache is still valid
        if (Date.now() - timestamp < CACHE_VALIDITY_MS) {
          this._words = words;
          this._version = version;
          console.log('[ContentSecurity] Loaded ' + words.length + ' words from cache (version: ' + version + ')');
        }
      }
    } catch (err) {
      console.error('[ContentSecurity] Failed to load cache:', err.message);
    }
  }

  /**
   * Save word list to local cache.
   */
  _saveToCache() {
    try {
      wx.setStorageSync(CACHE_KEY, this._words);
      wx.setStorageSync(CACHE_VERSION_KEY, this._version);
      wx.setStorageSync(CACHE_TIMESTAMP_KEY, Date.now());
    } catch (err) {
      console.error('[ContentSecurity] Failed to save cache:', err.message);
    }
  }

  /**
   * Get current word count.
   * @returns {number}
   */
  getWordCount() {
    return this._words.length;
  }

  /**
   * Get current version.
   * @returns {string}
   */
  getVersion() {
    return this._version;
  }

  /**
   * Check if initialized.
   * @returns {boolean}
   */
  isInitialized() {
    return this._initialized;
  }
}

// Export scene and report reason constants
ContentSecurityManager.SCENE = SCENE;
ContentSecurityManager.REPORT_REASONS = REPORT_REASONS;
ContentSecurityManager.REPORT_REASON_LABELS = REPORT_REASON_LABELS;

module.exports = ContentSecurityManager;