<script lang="ts" setup>
import ChatItem from '~/components/aigc/chat/ChatItem.vue'
import Message from '~/components/aigc/chat/Message.vue'
import {
  type Assistant,
  type ChatMessage,
  type ChatMessageId,
  type ChatSession,
  type ChatSessionId,
  llmModels,
  type ModelTag,
} from '~/typings/llm'
import { useHistory } from '~/composables/useHistory'
import { uuidv4 } from '@uniiem/uuid'
import { useLLM } from '~/composables/useLLM'
import { trimObject } from '@uniiem/object-trim'
import ModalAuthentication from '~/components/ModalAuthentication.vue'
import NewSessionScreen from '~/components/aigc/chat/NewSessionScreen.vue'

useSeoMeta({
  title: '聊天',
})

const dayjs = useDayjs()
const toast = useToast()
const modal = useModal()
const loginState = useLoginState()
const historyStore = useHistory()
const { chatSessions } = storeToRefs(historyStore)
const { setChatSessions } = historyStore

const currentSessionId = ref<ChatSessionId | null>(null)
const messagesWrapperRef = ref<HTMLDivElement | null>(null)

const showSidebar = ref(false)
const user_input = ref('')
const responding = ref(false)
const currentModel = ref<ModelTag>('spark3_5')
const currentAssistant = computed<Assistant | null>(() => getSessionCopyById(currentSessionId.value || '')?.assistant || null)
const modals = reactive({
  modelSelect: false,
  assistantSelect: false,
  newSessionScreen: false,
})

/**
 * 获取指定 ID 的会话数据
 * @param chatSessionId
 */
const getSessionCopyById = (chatSessionId: ChatSessionId): ChatSession | undefined => chatSessions.value.find(s => s.id === chatSessionId)
/**
 * 切换当前会话
 * @param chatSessionId 指定会话 ID，不传则切换到列表中第一个会话
 */
const selectCurrentSessionId = (chatSessionId?: ChatSessionId) => {
  if (chatSessions.value.length > 0) {
    if (chatSessionId) { // 切换到指定 ID
      // 保存当前输入并清空输入框
      setChatSessions(chatSessions.value.map(s => s.id === currentSessionId.value ? {
        ...s,
        last_input: user_input.value,
      } : s))
      user_input.value = ''
      // 切换到指定 ID 会话
      currentSessionId.value = chatSessionId
      // 恢复输入
      user_input.value = getSessionCopyById(chatSessionId)?.last_input || ''
      // 清除已恢复的输入
      setChatSessions(chatSessions.value.map(s => s.id === chatSessionId ? {
        ...s,
        last_input: '',
      } : s))
    } else { // 切换到第一个会话
      currentSessionId.value = chatSessions.value[0].id
    }
  } else {
    handleClickCreateSession()
  }
  nextTick(() => {
    showSidebar.value = false
    modals.newSessionScreen = false
    scrollToMessageListBottom()
  })
}

/**
 * 创建新会话处理函数
 * @param assistant 指定助手，不传或空值则不指定助手
 */
const createSession = (assistant: Assistant | null) => {
  // 生成一个新的会话 ID
  const sessionId = uuidv4()
  // 新会话数据
  const newChat = !!assistant ? {
    id: sessionId,
    subject: '新对话',
    messages: [],
    create_at: dayjs().unix(),
    assistant,
  } : {
    id: sessionId,
    subject: '新对话',
    messages: [],
    create_at: dayjs().unix(),
  }
  // 插入新会话数据
  setChatSessions([
    newChat,
    ...chatSessions.value,
  ])
  // 切换到新的会话
  selectCurrentSessionId(sessionId)
  // 关闭新建会话屏幕
  modals.newSessionScreen = false
  nextTick(() => {
    if (!!currentAssistant.value) {
      insetMessage({
        id: uuidv4(),
        role: 'system',
        content: currentAssistant.value?.role || '',
        preset: true,
      })
      insetMessage({
        id: uuidv4(),
        role: 'user',
        content: `${ currentAssistant.value?.target }，${ currentAssistant.value?.demand }`,
        preset: true,
      })
      insetMessage({
        id: uuidv4(),
        role: 'assistant',
        content: currentAssistant.value?.input_tpl || '',
        preset: true,
      })
    } else {
      insetMessage({
        id: uuidv4(),
        role: 'assistant',
        content: '你好，有什么可以帮助你的吗？',
        preset: true,
      })
    }
  })
}

/**
 * 处理点击新建会话按钮事件
 */
const handleClickCreateSession = () => {
  showSidebar.value = false
  modals.newSessionScreen = true
}

/**
 * 处理发送消息操作
 * @param event
 */
const handleClickSend = (event: any) => {
  if (!loginState.is_logged_in) {
    modal.open(ModalAuthentication)
    return
  }
  if (event.ctrlKey) {
    return
  }
  if (responding.value) return
  if (!user_input.value) return
  if (!currentSessionId.value) {
    toast.add({
      title: '发送失败',
      description: '请先选择一个会话',
      color: 'red',
      icon: 'i-tabler-circle-x',
    })
    return
  }
  // 插入用户消息
  insetMessage({
    id: uuidv4(),
    role: 'user',
    content: user_input.value,
    create_at: dayjs().unix(),
  })
  user_input.value = ''
  // 进入响应中状态
  responding.value = true
  // 插入空助手消息(加载状态)
  const assistantReplyId = insetMessage({
    id: uuidv4(),
    role: 'assistant',
    content: '',
  })
  // 请求模型回复
  const trimmedMessages = trimObject(getMessages(), 2000, {
    keys: ['content'],
  })
  useLLM(trimmedMessages, {
    modelTag: currentModel.value,
  }).then(reply => {
    modifyMessageContent(assistantReplyId, reply)
  }).catch(err => {
    modifyMessageContent(assistantReplyId, err, true)
  }).finally(() => {
    responding.value = false
  })
}

const scrollToMessageListBottom = () => {
  nextTick(() => {
    messagesWrapperRef.value?.scrollTo({
      top: messagesWrapperRef.value.scrollHeight,
      behavior: 'smooth',
    })
  })
}

const insetMessage = (message: ChatMessage): ChatMessageId => {
  setChatSessions(chatSessions.value.map(s => s.id === currentSessionId.value ? {
    ...s,
    messages: [
      ...s.messages,
      message,
    ],
  } : s))
  scrollToMessageListBottom()
  return message.id
}

const getMessages = () => getSessionCopyById(currentSessionId.value!)?.messages || []

const modifyMessageContent = (
    messageId: ChatMessageId,
    content: string,
    interrupted: boolean = false,
    updateTime: boolean = true,
) => {
  setChatSessions(chatSessions.value.map(s => s.id === currentSessionId.value ? {
    ...s,
    messages: s.messages.map(m => m.id === messageId ? {
      ...m,
      content,
      interrupted,
      create_at: updateTime ? dayjs().unix() : m.create_at,
    } : m),
  } : s))
  scrollToMessageListBottom()
}

onMounted(() => {
  // 切换到第一个会话, 没有会话会自动创建
  selectCurrentSessionId()
})
</script>

<template>
  <div class="w-full flex relative">
    <div
        class="absolute -translate-x-full md:sticky md:translate-x-0 z-10 flex flex-col h-[calc(100vh-4rem)] bg-neutral-100 dark:bg-neutral-900 p-4 w-full md:w-[300px]
               shadow-sidebar border-r border-transparent dark:border-neutral-700 transition-all duration-300 ease-out"
        :class="{'translate-x-0': showSidebar}"
    >
      <div class="flex-1 flex flex-col overflow-auto overflow-x-hidden">
        <!-- list -->
        <div class="flex flex-col gap-3 relative">
          <!-- ClientOnly avoids hydrate exception -->
          <ClientOnly>
            <TransitionGroup name="chat-item">
              <div v-if="chatSessions.length === 0">
                <div class="text-center text-neutral-400 dark:text-neutral-500 py-4 flex flex-col items-center gap-2">
                  <Icon name="i-tabler-messages" class="text-2xl"/>
                  <span>没有会话</span>
                </div>
              </div>
              <ChatItem
                  v-for="session in chatSessions"
                  :chat-session="session" :key="session.id"
                  :active="session.id === currentSessionId"
                  @click="selectCurrentSessionId(session.id)"
                  @remove="() => {
                  chatSessions.splice(chatSessions.findIndex(s => s.id === session.id), 1)
                  session.id === currentSessionId && selectCurrentSessionId()
                }"
              />
            </TransitionGroup>
          </ClientOnly>
        </div>
      </div>
      <div class="pt-4 flex justify-between items-center">
        <div></div>
        <div>
          <UButton
              color="white"
              variant="solid"
              icon="i-tabler-message-circle-plus"
              @click="handleClickCreateSession"
          >
            新建聊天
          </UButton>
        </div>
      </div>
    </div>
    <div class="h-[calc(100vh-4rem)] flex-1 bg-white dark:bg-neutral-900">

      <Transition name="message" mode="out-in">
        <div v-if="!loginState.is_logged_in" class="w-full h-full">
          <div class="w-full h-full flex flex-col justify-center items-center gap-2 bg-neutral-100 dark:bg-neutral-900">
            <Icon name="i-tabler-user-circle" class="text-7xl text-neutral-300 dark:text-neutral-700"/>
            <p class="text-sm text-neutral-500 dark:text-neutral-400">请登录后使用</p>
            <UButton class="mt-2 font-bold" color="black" variant="solid" size="xs"
                     @click="modal.open(ModalAuthentication)">
              登录
            </UButton>
          </div>
        </div>
        <NewSessionScreen
            v-else-if="modals.newSessionScreen || getSessionCopyById(currentSessionId!) === undefined"
            :non-back="!getSessionCopyById(currentSessionId!)"
            @select="createSession"
            @cancel="modals.newSessionScreen = false"
        />
        <div
            v-else
            class="w-full h-full flex flex-col"
        >
          <div
              class="w-full p-4 bg-neutral-50 dark:bg-neutral-800/50 border-b dark:border-neutral-700/50 flex items-center gap-2">
            <UButton
                class="md:hidden"
                color="black"
                variant="ghost"
                icon="i-tabler-menu-2"
                @click="showSidebar = !showSidebar"
            >
            </UButton>
            <h1 class="font-medium">{{ getSessionCopyById(currentSessionId!)?.subject || '新对话' }}</h1>
          </div>
          <div ref="messagesWrapperRef" class="flex-1 flex flex-col overflow-auto overflow-x-hidden">
            <div class="flex flex-col gap-8 px-4 py-8">
              <TransitionGroup name="message">
                <Message
                    v-for="message in getMessages() || []"
                    :message="message"
                    :key="message.id"
                />
              </TransitionGroup>
            </div>
          </div>
          <ClientOnly>
            <div
                class="w-full p-4 pt-2 flex flex-col gap-2 bg-neutral-50 dark:bg-neutral-800/50 border-t dark:border-neutral-700/50">
              <div class="flex items-center gap-2 overflow-auto overflow-y-hidden">
                <button class="chat-option-btn" @click="modals.modelSelect = true">
                  <Icon name="tabler:box"/>
                  <span class="text-xs">
                    {{ llmModels.find(m => m.tag === currentModel)?.name.toUpperCase() || '模型' }}
                  </span>
                </button>
                <button
                    v-if="currentAssistant?.tpl_name"
                    class="chat-option-btn"
                >
                  <Icon name="tabler:robot-face"/>
                  <span class="text-xs">
                    {{ currentAssistant.tpl_name }}
                  </span>
                </button>
              </div>
              <div class="relative">
                <UTextarea
                    v-model="user_input"
                    size="lg"
                    autoresize
                    :rows="5"
                    :maxrows="12"
                    class="font-sans"
                    placeholder="Enter 发送, Ctrl + Enter 换行"
                    @keydown.ctrl.enter="user_input += '\n'"
                    @keydown.enter.prevent="handleClickSend"
                />
                <UButton
                    color="black"
                    variant="solid"
                    icon="i-tabler-send-2"
                    class="absolute bottom-2.5 right-3"
                    @click.stop="handleClickSend"
                >
                  发送
                </UButton>
              </div>
            </div>
          </ClientOnly>
        </div>
      </Transition>

    </div>

    <!-- Modals -->
    <UModal v-model="modals.modelSelect">
      <UCard>
        <template #header>
          <h3 class="text-base font-semibold leading-6 text-gray-900 dark:text-white">
            选择大语言模型
          </h3>
        </template>
        <div class="grid grid-cols-3 gap-4">
          <div
              v-for="(llm, index) in llmModels"
              :key="index"
              @click="currentModel = llm.tag"
              class="flex flex-col gap-2 justify-center items-center w-full aspect-[1/1] border-2 rounded-xl cursor-pointer transition duration-150 select-none"
              :class="llm.tag === currentModel ? 'border-primary shadow-xl bg-primary text-white' : 'dark:border-neutral-800 bg-white dark:bg-black shadow-card'"
          >
            <Icon v-if="llm?.icon" :name="llm.icon" class="text-4xl opacity-80"/>
            <div class="flex flex-col gap-0.5 items-center">
              <h1 class="font-bold drop-shadow opacity-90">{{ llm.name || 'unknown' }}</h1>
              <p class="text-xs opacity-60">{{ llm.description }}</p>
            </div>
          </div>
        </div>
        <template #footer>
          <div class="flex justify-end items-center" @click="modals.modelSelect = false">
            <UButton>
              确定
            </UButton>
          </div>
        </template>
      </UCard>
    </UModal>

  </div>
</template>

<!--suppress CssUnusedSymbol -->
<style scoped>
.message-enter-active {
  @apply transition duration-300;
}

.message-enter-from {
  @apply translate-y-4 opacity-0;
}

.chat-item-move,
.chat-item-enter-active,
.chat-item-leave-active {
  @apply transition-all duration-300;
}

.chat-item-enter-from,
.chat-item-leave-to {
  @apply opacity-0 scale-90;
}

.chat-item-leave-active {
  @apply absolute inset-x-0;
}

.chat-option-btn {
  @apply text-lg px-2 py-1.5 flex gap-1 justify-center items-center rounded-lg;
  @apply bg-white border border-neutral-300 shadow-sm hover:shadow-card;
  @apply dark:bg-neutral-800 dark:border-neutral-600;
}
</style>