import { ref } from 'vue'
import { useEventBus } from './useEventBus'
import type { StructureInfo } from './useEventBus'
import { STORAGE_KEYS } from '../constants/storage'
import { getTableStructure } from '@/api'

class StructureStore {
  public readonly loading = ref(false)
  public readonly error = ref('')
  public readonly data = ref<any>(null)
  public readonly info = ref<StructureInfo | null>(null)

  private eventBus = useEventBus()

  setLoading(loading: boolean): void {
    this.loading.value = loading
    this.eventBus.emit('structure:loading', { loading })
  }

  setError(error: string): void {
    this.error.value = error
    this.eventBus.emit('structure:error', { error })
  }

  setData(data: any, info: StructureInfo): void {
    this.data.value = data
    this.info.value = info
    this.error.value = ''
    this.loading.value = false
    try {
      localStorage.setItem(STORAGE_KEYS.STRUCTURE_INFO, JSON.stringify(info))
    } catch {}
    this.eventBus.emit('structure:data', { data, info })
  }

  clear(): void {
    this.data.value = null
    this.info.value = null
    this.error.value = ''
    this.loading.value = false
    try {
      localStorage.removeItem(STORAGE_KEYS.STRUCTURE_INFO)
    } catch {}
    this.eventBus.emit('structure:clear', {})
  }

  restoreStructureInfo(): StructureInfo | null {
    try {
      const saved = localStorage.getItem(STORAGE_KEYS.STRUCTURE_INFO)
      return saved ? JSON.parse(saved) as StructureInfo : null
    } catch {
      return null
    }
  }

  async loadStructure(
    connectionId: number,
    database: string,
    tableName: string,
    dbType: 'mysql' | 'mongo' | 'redis',
    nodeType: string
  ): Promise<void> {
    // 跳过非表节点
    if (nodeType === 'connection' || nodeType === 'database' || !tableName) {
      this.info.value = { connectionId, database, tableName: '', dbType, nodeType }
      this.data.value = null
      return
    }

    // 检查是否切换到不同的表
    const currentInfo = this.info.value
    const isDifferentTable = !currentInfo ||
      currentInfo.connectionId !== connectionId ||
      currentInfo.database !== database ||
      currentInfo.tableName !== tableName

    if (isDifferentTable) {
      this.data.value = null
      this.error.value = ''
    }

    try {
      this.setLoading(true)

      const result = await getTableStructure(
        connectionId,
        database,
        tableName
      )

      this.setData(result, { connectionId, database, tableName, dbType, nodeType })
    } catch (error: unknown) {
      const errorMsg = error instanceof Error ? error.message : '加载表结构失败'
      this.setError(errorMsg)
      this.data.value = null
      this.info.value = null
    } finally {
      this.setLoading(false)
    }
  }

  async refreshStructure(): Promise<void> {
    if (!this.info.value) return
    await this.loadStructure(
      this.info.value.connectionId,
      this.info.value.database,
      this.info.value.tableName,
      this.info.value.dbType,
      this.info.value.nodeType
    )
  }
}

let structureStoreInstance: StructureStore | null = null

export function useStructureStore(): StructureStore {
  if (!structureStoreInstance) {
    structureStoreInstance = new StructureStore()
  }
  return structureStoreInstance
}

export type { StructureInfo }