/**
 * Wrapper around window.localStorage for the Respellion platform.
 * Handles serialization/deserialization, namespaces, and quota limits.
 */

const STORAGE_PREFIX = 'respellion:';

export const storage = {
  /**
   * Get an item from storage
   * @param {string} key - e.g. 'kb:topics'
   * @returns {any}
   */
  get(key, defaultValue = null) {
    try {
      const item = window.localStorage.getItem(STORAGE_PREFIX + key);
      return item ? JSON.parse(item) : defaultValue;
    } catch (e) {
      console.error(`Error reading ${key} from storage:`, e);
      return defaultValue;
    }
  },

  /**
   * Set an item in storage
   * @param {string} key 
   * @param {any} value 
   */
  set(key, value) {
    try {
      const serialized = JSON.stringify(value);
      window.localStorage.setItem(STORAGE_PREFIX + key, serialized);
    } catch (e) {
      if (e.name === 'QuotaExceededError' || e.code === 22) {
        console.error(`Storage quota exceeded when setting ${key}.`);
      } else {
        console.error(`Error saving ${key} to storage:`, e);
      }
    }
  },

  /**
   * Remove an item from storage
   * @param {string} key 
   */
  remove(key) {
    try {
      window.localStorage.removeItem(STORAGE_PREFIX + key);
    } catch (e) {
      console.error(`Error removing ${key} from storage:`, e);
    }
  },

  /**
   * Get all keys matching a specific prefix (e.g. 'kb:topics:')
   * @param {string} prefix 
   * @returns {string[]} Array of matching keys (without the STORAGE_PREFIX)
   */
  getKeysByPrefix(prefix) {
    const keys = [];
    const fullPrefix = STORAGE_PREFIX + prefix;
    for (let i = 0; i < window.localStorage.length; i++) {
      const key = window.localStorage.key(i);
      if (key && key.startsWith(fullPrefix)) {
        keys.push(key.substring(STORAGE_PREFIX.length));
      }
    }
    return keys;
  }
};