Add Chats

src/services/chat_service/chat_service.js

@@ -0,0 +1,150 @@
+import _ from 'lodash'
+
+const empty = (chatId) => {
+  return {
+    idIndex: {},
+    messages: [],
+    newMessageCount: 0,
+    lastSeenTimestamp: 0,
+    chatId: chatId,
+    minId: undefined,
+    lastMessage: undefined
+  }
+}
+
+const clear = (storage) => {
+  storage.idIndex = {}
+  storage.messages.splice(0, storage.messages.length)
+  storage.newMessageCount = 0
+  storage.lastSeenTimestamp = 0
+  storage.minId = undefined
+  storage.lastMessage = undefined
+}
+
+const deleteMessage = (storage, messageId) => {
+  if (!storage) { return }
+  storage.messages = storage.messages.filter(m => m.id !== messageId)
+  delete storage.idIndex[messageId]
+
+  if (storage.lastMessage && (storage.lastMessage.id === messageId)) {
+    storage.lastMessage = _.maxBy(storage.messages, 'id')
+  }
+
+  if (storage.minId === messageId) {
+    storage.minId = _.minBy(storage.messages, 'id')
+  }
+}
+
+const add = (storage, { messages: newMessages }) => {
+  if (!storage) { return }
+  for (let i = 0; i < newMessages.length; i++) {
+    const message = newMessages[i]
+
+    // sanity check
+    if (message.chat_id !== storage.chatId) { return }
+
+    if (!storage.minId || message.id < storage.minId) {
+      storage.minId = message.id
+    }
+
+    if (!storage.lastMessage || message.id > storage.lastMessage.id) {
+      storage.lastMessage = message
+    }
+
+    if (!storage.idIndex[message.id]) {
+      if (storage.lastSeenTimestamp < message.created_at) {
+        storage.newMessageCount++
+      }
+      storage.messages.push(message)
+      storage.idIndex[message.id] = message
+    }
+  }
+}
+
+const resetNewMessageCount = (storage) => {
+  if (!storage) { return }
+  storage.newMessageCount = 0
+  storage.lastSeenTimestamp = new Date()
+}
+
+// Inserts date separators and marks the head and tail if it's the chain of messages made by the same user
+const getView = (storage) => {
+  if (!storage) { return [] }
+
+  const result = []
+  const messages = _.sortBy(storage.messages, ['id', 'desc'])
+  const firstMessages = messages[0]
+  let prev = messages[messages.length - 1]
+  let currentMessageChainId
+
+  if (firstMessages) {
+    const date = new Date(firstMessages.created_at)
+    date.setHours(0, 0, 0, 0)
+    result.push({
+      type: 'date',
+      date,
+      id: date.getTime().toString()
+    })
+  }
+
+  let afterDate = false
+
+  for (let i = 0; i < messages.length; i++) {
+    const message = messages[i]
+    const nextMessage = messages[i + 1]
+
+    const date = new Date(message.created_at)
+    date.setHours(0, 0, 0, 0)
+
+    // insert date separator and start a new message chain
+    if (prev && prev.date < date) {
+      result.push({
+        type: 'date',
+        date,
+        id: date.getTime().toString()
+      })
+
+      prev['isTail'] = true
+      currentMessageChainId = undefined
+      afterDate = true
+    }
+
+    const object = {
+      type: 'message',
+      data: message,
+      date,
+      id: message.id,
+      messageChainId: currentMessageChainId
+    }
+
+    // end a message chian
+    if ((nextMessage && nextMessage.account_id) !== message.account_id) {
+      object['isTail'] = true
+      currentMessageChainId = undefined
+    }
+
+    // start a new message chain
+    if ((prev && prev.data && prev.data.account_id) !== message.account_id || afterDate) {
+      currentMessageChainId = _.uniqueId()
+      object['isHead'] = true
+      object['messageChainId'] = currentMessageChainId
+    }
+
+    result.push(object)
+    prev = object
+    afterDate = false
+  }
+
+  return result
+}
+
+const ChatService = {
+  add,
+  empty,
+  getView,
+  deleteMessage,
+  resetNewMessageCount,
+  clear
+}
+
+export default ChatService