import { apiRequest, _getToken, _saveToken, getConfig, getDeviceInfo } from '@xuqm/rn-common'
import { ImClient } from './ImClient'
import { ImDatabase } from './db/ImDatabase'
import type { MessageSearchParams } from './db/ImDatabase'
import type { ChatType, ImEventListener, ImGroup, ImMessage, MsgType } from './types'
import { uploadFile } from './upload'

let client: ImClient | null = null
let _currentUserId: string | null = null

export interface ConversationData {
  targetId: string
  chatType: 'SINGLE' | 'GROUP'
  lastMsgContent: string
  lastMsgType: string
  lastMsgTime: number
  unreadCount: number
  isMuted: boolean
  isPinned: boolean
}

async function _syncHistoryForAllConversations(): Promise<void> {
  const config = getConfig()
  if (!ImDatabase.isInitialized() || !_currentUserId) return

  try {
    // Fetch top 20 conversations from server
    const res = await apiRequest<ImMessage[] | { content?: ImMessage[] }>(
      '/api/im/conversations',
      { params: { appId: config.appId, page: '0', size: '20' } },
    )
    const serverConversations = Array.isArray(res) ? res : (res.content ?? [])

    // For each conversation, fetch last 30 messages and save locally
    // serverConversations items may be conversation summaries; we use the common
    // history endpoint that accepts a targetId. If the response is ImMessage[]
    // we extract unique toIds.
    const targetIds: string[] = []
    for (const item of serverConversations as any[]) {
      const targetId: string | undefined = item.targetId ?? item.toId ?? item.id
      if (targetId && !targetIds.includes(targetId)) {
        targetIds.push(targetId)
      }
    }

    await Promise.all(
      targetIds.map(async (targetId) => {
        try {
          const msgRes = await apiRequest<{ content?: ImMessage[] } | ImMessage[]>(
            `/api/im/messages/history/${encodeURIComponent(targetId)}`,
            { params: { appId: config.appId, page: '0', size: '30' } },
          )
          const messages = Array.isArray(msgRes) ? msgRes : (msgRes.content ?? [])
          if (messages.length > 0 && _currentUserId) {
            await ImDatabase.bulkSave(messages, _currentUserId)
          }
        } catch {
          // Silently skip conversations that fail to sync
        }
      }),
    )
  } catch {
    // Sync is best-effort; do not throw
  }
}

export const ImSDK = {
  /**
   * Login to IM service. Fetches a token internally and opens the WebSocket connection.
   * Pass dbName to enable local SQLite message caching (requires @nozbe/watermelondb).
   */
  async login(userId: string, nickname?: string, avatar?: string, dbName?: string): Promise<void> {
    const config = getConfig()
    const device = await getDeviceInfo()
    const res = await apiRequest<{ token: string }>('/api/im/auth/login', {
      method: 'POST',
      skipAuth: true,
      params: {
        appId:     config.appId,
        userId,
        deviceId:  device.deviceId,
        platform:  device.platform,
        brand:     device.brand,
        model:     device.model,
        osVersion: device.osVersion,
        ...(nickname ? { nickname } : {}),
        ...(avatar ? { avatar } : {}),
      },
    })
    await _saveToken(res.token)
    _currentUserId = userId

    if (dbName !== undefined || ImDatabase.isInitialized()) {
      ImDatabase.init(dbName ?? 'xuqm_im')
    }

    client = new ImClient(config.imWsUrl, res.token, config.appId)
    client.addListener({
      onConnected: () => {
        _syncHistoryForAllConversations().catch(() => {})
      },
    })
    client.connect()
  },

  /**
   * Login with a pre-obtained IM token (e.g. from demo-service).
   * Sets up the IM connection without calling the auth endpoint.
   */
  async loginWithToken(userId: string, token: string, dbName?: string): Promise<void> {
    const config = getConfig()
    await _saveToken(token)
    _currentUserId = userId

    if (dbName !== undefined || ImDatabase.isInitialized()) {
      ImDatabase.init(dbName ?? 'xuqm_im')
    }

    client = new ImClient(config.imWsUrl, token, config.appId)
    client.addListener({
      onConnected: () => {
        _syncHistoryForAllConversations().catch(() => {})
      },
    })
    client.connect()
  },

  async reconnect(): Promise<void> {
    const config = getConfig()
    const token = await _getToken()
    if (!token) throw new Error('[ImSDK] No active session — call login() first.')
    client = new ImClient(config.imWsUrl, token, config.appId)
    client.connect()
  },

  /**
   * Fetch message history. Reads from local DB first; falls back to server if DB is empty
   * or not initialized, then caches results locally.
   */
  async fetchHistory(toId: string, page = 0, size = 20): Promise<ImMessage[]> {
    const config = getConfig()

    if (ImDatabase.isInitialized() && page === 0 && _currentUserId) {
      const local = await ImDatabase.getMessages(config.appId, toId, 'SINGLE', _currentUserId, size)
      if (local.length > 0) {
        return local.map(m => ({
          id: m.serverId,
          appId: m.appId,
          fromUserId: m.fromUserId,
          toId: m.toId,
          chatType: m.chatType as ChatType,
          msgType: m.msgType as MsgType,
          content: m.content,
          status: m.status as ImMessage['status'],
          mentionedUserIds: m.mentionedUserIds ?? undefined,
          createdAt: new Date(m.serverCreatedAt).toISOString(),
        }))
      }
    }

    const res = await apiRequest<{ content?: ImMessage[] } | ImMessage[]>(
      `/api/im/messages/history/${encodeURIComponent(toId)}`,
      { params: { appId: config.appId, page: String(page), size: String(size) } },
    )
    const messages = Array.isArray(res) ? res : (res.content ?? [])

    if (ImDatabase.isInitialized() && _currentUserId) {
      await ImDatabase.bulkSave(messages, _currentUserId)
    }

    return messages
  },

  async sendMessage(
    toId: string,
    chatType: ChatType,
    msgType: MsgType,
    content: string,
    mentionedUserIds?: string,
  ): Promise<ImMessage> {
    const config = getConfig()
    const msg = await apiRequest<ImMessage>('/api/im/messages/send', {
      method: 'POST',
      params: { appId: config.appId },
      body: { toId, chatType, msgType, content, mentionedUserIds: mentionedUserIds ?? '' },
    })
    if (ImDatabase.isInitialized() && _currentUserId) {
      await ImDatabase.saveMessage(msg, _currentUserId)
    }
    return msg
  },

  async revokeMessage(messageId: string): Promise<ImMessage> {
    const config = getConfig()
    const msg = await apiRequest<ImMessage>(`/api/im/messages/${encodeURIComponent(messageId)}/revoke`, {
      method: 'POST',
      params: { appId: config.appId },
    })
    if (ImDatabase.isInitialized() && _currentUserId) {
      await ImDatabase.saveMessage(msg, _currentUserId)
    }
    return msg
  },

  async createGroup(name: string, memberIds: string[]): Promise<ImGroup> {
    const config = getConfig()
    return apiRequest<ImGroup>('/api/im/groups', {
      method: 'POST',
      params: { appId: config.appId },
      body: { name, memberIds },
    })
  },

  async listGroups(): Promise<ImGroup[]> {
    const config = getConfig()
    const res = await apiRequest<ImGroup[] | { content?: ImGroup[] }>('/api/im/groups', {
      params: { appId: config.appId },
    })
    return Array.isArray(res) ? res : (res.content ?? [])
  },

  async fetchGroupHistory(groupId: string, page = 0, size = 50): Promise<ImMessage[]> {
    const config = getConfig()

    if (ImDatabase.isInitialized() && page === 0 && _currentUserId) {
      const local = await ImDatabase.getMessages(config.appId, groupId, 'GROUP', _currentUserId, size)
      if (local.length > 0) {
        return local.map(m => ({
          id: m.serverId,
          appId: m.appId,
          fromUserId: m.fromUserId,
          toId: m.toId,
          chatType: m.chatType as ChatType,
          msgType: m.msgType as MsgType,
          content: m.content,
          status: m.status as ImMessage['status'],
          mentionedUserIds: m.mentionedUserIds ?? undefined,
          createdAt: new Date(m.serverCreatedAt).toISOString(),
        }))
      }
    }

    const res = await apiRequest<{ content?: ImMessage[] } | ImMessage[]>(
      `/api/im/messages/history/${encodeURIComponent(groupId)}`,
      { params: { appId: config.appId, page: String(page), size: String(size) } },
    )
    const messages = Array.isArray(res) ? res : (res.content ?? [])

    if (ImDatabase.isInitialized() && _currentUserId) {
      await ImDatabase.bulkSave(messages, _currentUserId)
    }

    return messages
  },

  /** List all conversations from local DB sorted by last message time. */
  async listConversations() {
    if (!ImDatabase.isInitialized()) return []
    const config = getConfig()
    return ImDatabase.getConversations(config.appId)
  },

  /**
   * Subscribe to conversation list changes.
   * Fires immediately with current data, then on every change (new message, read, mute, pin, etc.).
   * Returns an unsubscribe function.
   */
  subscribeConversations(callback: (conversations: ConversationData[]) => void): () => void {
    if (!ImDatabase.isInitialized()) {
      // Return no-op if DB not ready
      return () => {}
    }
    const config = getConfig()
    return ImDatabase.subscribeConversations(config.appId, (models) => {
      const data: ConversationData[] = models.map(c => ({
        targetId: c.targetId,
        chatType: c.chatType as 'SINGLE' | 'GROUP',
        lastMsgContent: c.lastMsgContent ?? '',
        lastMsgType: c.lastMsgType ?? '',
        lastMsgTime: c.lastMsgTime,
        unreadCount: c.unreadCount,
        isMuted: c.isMuted,
        isPinned: c.isPinned,
      }))
      callback(data)
    })
  },

  /** Mark a conversation as read (clears unread count). */
  async markRead(targetId: string): Promise<void> {
    if (!ImDatabase.isInitialized()) return
    const config = getConfig()
    await ImDatabase.markRead(config.appId, targetId)
  },

  /**
   * Fetch last page of messages for each known conversation from server and save locally.
   * Called automatically after connection is established via login/loginWithToken.
   */
  async syncHistoryForAllConversations(): Promise<void> {
    await _syncHistoryForAllConversations()
  },

  /**
   * Search messages in local DB.
   * appId defaults to the configured appId if not provided.
   */
  async searchMessages(params: MessageSearchParams & { appId?: string }) {
    if (!ImDatabase.isInitialized()) return []
    const config = getConfig()
    const { appId, ...rest } = params
    return ImDatabase.searchMessages(appId ?? config.appId, rest)
  },

  addListener(listener: ImEventListener): void {
    client?.addListener({
      ...listener,
      onMessage: async (msg) => {
        if (ImDatabase.isInitialized() && _currentUserId) {
          await ImDatabase.saveMessage(msg, _currentUserId)
        }
        listener.onMessage?.(msg)
      },
      onGroupMessage: async (msg) => {
        if (ImDatabase.isInitialized() && _currentUserId) {
          await ImDatabase.saveMessage(msg, _currentUserId)
        }
        listener.onGroupMessage?.(msg)
      },
    })
  },

  removeListener(listener: ImEventListener): void { client?.removeListener(listener) },
  subscribeGroup(groupId: string): void { client?.subscribeGroup(groupId) },
  isConnected(): boolean { return client?.isConnected() ?? false },

  /**
   * Upload a local image and send it as an IMAGE message.
   * The file-service generates a thumbnail automatically for image/* content.
   */
  async sendImageMessage(
    toId: string,
    chatType: ChatType,
    localUri: string,
    width?: number,
    height?: number,
  ): Promise<ImMessage> {
    const filename = localUri.split('/').pop() ?? 'image.jpg'
    const mimeType = resolveMimeTypeFromUri(localUri, 'image/jpeg')
    const result = await uploadFile(localUri, mimeType, filename)
    const content = JSON.stringify({
      url: result.url,
      thumbnailUrl: result.thumbnailUrl,
      width: width ?? 0,
      height: height ?? 0,
      size: result.size,
      name: result.originalName,
    })
    return ImSDK.sendMessage(toId, chatType, 'IMAGE', content)
  },

  /**
   * Upload a local video (with optional pre-generated thumbnail) and send as a VIDEO message.
   */
  async sendVideoMessage(
    toId: string,
    chatType: ChatType,
    localUri: string,
    thumbnailUri?: string,
    duration?: number,
  ): Promise<ImMessage> {
    const filename = localUri.split('/').pop() ?? 'video.mp4'
    const mimeType = resolveMimeTypeFromUri(localUri, 'video/mp4')
    const result = await uploadFile(localUri, mimeType, filename, thumbnailUri)
    const content = JSON.stringify({
      url: result.url,
      thumbnailUrl: result.thumbnailUrl,
      duration: duration ?? 0,
      size: result.size,
      width: 0,
      height: 0,
    })
    return ImSDK.sendMessage(toId, chatType, 'VIDEO', content)
  },

  /**
   * Upload a local audio file and send as an AUDIO message.
   */
  async sendAudioMessage(
    toId: string,
    chatType: ChatType,
    localUri: string,
    duration: number,
  ): Promise<ImMessage> {
    const filename = localUri.split('/').pop() ?? 'audio.m4a'
    const mimeType = resolveMimeTypeFromUri(localUri, 'audio/mp4')
    const result = await uploadFile(localUri, mimeType, filename)
    const content = JSON.stringify({
      url: result.url,
      duration,
      size: result.size,
    })
    return ImSDK.sendMessage(toId, chatType, 'AUDIO', content)
  },

  /**
   * Upload a local file and send as a FILE message.
   */
  async sendFileMessage(
    toId: string,
    chatType: ChatType,
    localUri: string,
    filename: string,
    size: number,
  ): Promise<ImMessage> {
    const mimeType = resolveMimeTypeFromUri(localUri, 'application/octet-stream')
    const result = await uploadFile(localUri, mimeType, filename)
    const content = JSON.stringify({
      url: result.url,
      name: filename,
      size,
      mimeType: result.mimeType,
    })
    return ImSDK.sendMessage(toId, chatType, 'FILE', content)
  },

  disconnect(): void {
    client?.disconnect()
    client = null
    _currentUserId = null
  },
}

// ---------------------------------------------------------------------------
// Internal helpers
// ---------------------------------------------------------------------------

function resolveMimeTypeFromUri(uri: string, fallback: string): string {
  const lower = uri.toLowerCase().split('?')[0]
  if (lower.endsWith('.jpg') || lower.endsWith('.jpeg')) return 'image/jpeg'
  if (lower.endsWith('.png'))  return 'image/png'
  if (lower.endsWith('.gif'))  return 'image/gif'
  if (lower.endsWith('.webp')) return 'image/webp'
  if (lower.endsWith('.mp4'))  return 'video/mp4'
  if (lower.endsWith('.mov'))  return 'video/quicktime'
  if (lower.endsWith('.m4a'))  return 'audio/mp4'
  if (lower.endsWith('.mp3'))  return 'audio/mpeg'
  if (lower.endsWith('.aac'))  return 'audio/aac'
  if (lower.endsWith('.pdf'))  return 'application/pdf'
  return fallback
}