import { openDB } from 'idb';
import { DATA_VERSION } from './version';
import { cacheableModels, cacheableModelNames } from './cacheableModels';

export class DataManager {
  constructor(accountId) {
    this.modelsToSync = cacheableModelNames;
    this.accountId = accountId;
    this.db = null;
  }

  async initDb() {
    if (this.db) return this.db;
    const dbName = `cw-store-${this.accountId}`;
    this.db = await openDB(dbName, DATA_VERSION, {
      upgrade(db, oldVersion, _newVersion, tx) {
        // Flush data carried over from a previous schema version so a
        // DATA_VERSION bump acts as a global cache reset. oldVersion === 0 on
        // first install, so fresh devices skip this. Clearing before creating
        // means we only ever clear stores that pre-existed this upgrade.
        if (oldVersion > 0) {
          for (let index = 0; index < db.objectStoreNames.length; index += 1) {
            tx.objectStore(db.objectStoreNames.item(index)).clear();
          }
        }

        if (!db.objectStoreNames.contains('cache-keys')) {
          db.createObjectStore('cache-keys');
        }
        cacheableModels.forEach(model => {
          if (!db.objectStoreNames.contains(model.name)) {
            db.createObjectStore(model.name, { keyPath: 'id' });
          }
        });
      },
    });

    // Store the database name in LocalStorage
    const dbNames = JSON.parse(localStorage.getItem('cw-idb-names') || '[]');
    if (!dbNames.includes(dbName)) {
      dbNames.push(dbName);
      localStorage.setItem('cw-idb-names', JSON.stringify(dbNames));
    }

    return this.db;
  }

  validateModel(name) {
    if (!name) throw new Error('Model name is not defined');
    if (!this.modelsToSync.includes(name)) {
      throw new Error(`Model ${name} is not defined`);
    }
    return true;
  }

  async replace({ modelName, data }) {
    this.validateModel(modelName);

    await this.db.clear(modelName);
    return this.push({ modelName, data });
  }

  async push({ modelName, data }) {
    this.validateModel(modelName);

    if (Array.isArray(data)) {
      const tx = this.db.transaction(modelName, 'readwrite');
      data.forEach(item => {
        tx.store.add(item);
      });
      await tx.done;
    } else {
      await this.db.add(modelName, data);
    }
  }

  async get({ modelName }) {
    this.validateModel(modelName);
    return this.db.getAll(modelName);
  }

  async setCacheKeys(cacheKeys) {
    await Promise.all(
      Object.entries(cacheKeys).map(([modelName, value]) =>
        this.db.put('cache-keys', value, modelName)
      )
    );
  }

  async getCacheKey(modelName) {
    this.validateModel(modelName);

    return this.db.get('cache-keys', modelName);
  }
}