// IndexedDB 封装工具
const DB_NAME = 'LotteryDB'
const DB_VERSION = 1
const STORE_NAME = 'lotteryData'

class IndexedDBHelper {
  constructor() {
    this.db = null
  }

  async init() {
    return new Promise((resolve, reject) => {
      const request = window.indexedDB.open(DB_NAME, DB_VERSION)

      request.onerror = () => {
        reject(new Error('Failed to open IndexedDB'))
      }

      request.onsuccess = () => {
        this.db = request.result
        resolve(this.db)
      }

      request.onupgradeneeded = (event) => {
        const db = event.target.result
        if (!db.objectStoreNames.contains(STORE_NAME)) {
          db.createObjectStore(STORE_NAME)
        }
      }
    })
  }

  async set(key, value) {
    if (!this.db) await this.init()
    
    return new Promise((resolve, reject) => {
      const transaction = this.db.transaction([STORE_NAME], 'readwrite')
      const store = transaction.objectStore(STORE_NAME)
      const request = store.put(value, key)

      request.onsuccess = () => {
        console.log(`IndexedDB: Successfully saved ${key}`)
        resolve()
      }
      request.onerror = () => {
        console.error(`IndexedDB: Failed to save ${key}`, request.error)
        reject(new Error('Failed to save to IndexedDB'))
      }
    })
  }

  async get(key) {
    if (!this.db) await this.init()
    
    return new Promise((resolve, reject) => {
      const transaction = this.db.transaction([STORE_NAME], 'readonly')
      const store = transaction.objectStore(STORE_NAME)
      const request = store.get(key)

      request.onsuccess = () => {
        console.log(`IndexedDB: Retrieved ${key}:`, request.result ? 'Yes' : 'No')
        resolve(request.result)
      }
      request.onerror = () => {
        console.error(`IndexedDB: Failed to retrieve ${key}`)
        reject(new Error('Failed to read from IndexedDB'))
      }
    })
  }

  async delete(key) {
    if (!this.db) await this.init()
    
    return new Promise((resolve, reject) => {
      const transaction = this.db.transaction([STORE_NAME], 'readwrite')
      const store = transaction.objectStore(STORE_NAME)
      const request = store.delete(key)

      request.onsuccess = () => resolve()
      request.onerror = () => reject(new Error('Failed to delete from IndexedDB'))
    })
  }

  async getAll() {
    if (!this.db) await this.init()
    
    return new Promise((resolve, reject) => {
      const transaction = this.db.transaction([STORE_NAME], 'readonly')
      const store = transaction.objectStore(STORE_NAME)
      const keysRequest = store.getAllKeys()
      
      const result = {}
      let completed = 0
      let totalKeys = 0

      keysRequest.onsuccess = () => {
        const keys = keysRequest.result
        totalKeys = keys.length
        console.log(`IndexedDB: Found ${totalKeys} keys:`, keys)
        
        if (totalKeys === 0) {
          resolve(result)
          return
        }

        keys.forEach(key => {
          const getRequest = store.get(key)
          getRequest.onsuccess = () => {
            result[key] = getRequest.result
            console.log(`IndexedDB: Retrieved ${key}:`, getRequest.result ? 'Yes' : 'No')
            completed++
            if (completed === totalKeys) {
              console.log('IndexedDB: All data retrieved:', Object.keys(result))
              resolve(result)
            }
          }
          getRequest.onerror = () => {
            console.error(`IndexedDB: Failed to retrieve ${key}`)
            completed++
            if (completed === totalKeys) {
              resolve(result)
            }
          }
        })
      }

      keysRequest.onerror = () => reject(new Error('Failed to read all from IndexedDB'))
    })
  }

  async clear() {
    if (!this.db) await this.init()
    
    return new Promise((resolve, reject) => {
      const transaction = this.db.transaction([STORE_NAME], 'readwrite')
      const store = transaction.objectStore(STORE_NAME)
      const request = store.clear()

      request.onsuccess = () => resolve()
      request.onerror = () => reject(new Error('Failed to clear IndexedDB'))
    })
  }
}

export const indexedDB = new IndexedDBHelper()