import { defineStore } from "pinia";
import { ref } from "vue";

import {
  createConversation,
  fetchConversation,
  fetchConversations,
  withdrawConversationMessage,
  streamConversationMessage,
  sendConversationMessage,
} from "@/api/conversations";
import type { Conversation, ConversationSummary } from "@/types/conversation";

type ConversationMessageType = "text" | "image" | "file" | "audio";

export const useConversationStore = defineStore("conversation", () => {
  const items = ref<ConversationSummary[]>([]);
  const current = ref<Conversation | null>(null);
  const loading = ref(false);
  const sending = ref(false);
  const loadingOlder = ref(false);
  const error = ref<string | null>(null);
  const generating = ref(false);
  let activeController: AbortController | null = null;
  let activeUserMessageId: number | null = null;
  let listRequest: Promise<void> | null = null;
  let listRequestSearch: string | undefined;
  let listLoadedAt = 0;

  async function loadList(search?: string) {
    const normalizedSearch = search?.trim() || undefined;
    if (listRequest && listRequestSearch === normalizedSearch)
      return listRequest;
    if (
      !normalizedSearch &&
      items.value.length &&
      Date.now() - listLoadedAt < 30_000
    )
      return;
    loading.value = true;
    error.value = null;
    listRequestSearch = normalizedSearch;
    listRequest = (async () => {
      try {
        const response = await fetchConversations(50, normalizedSearch);
        items.value = response.data.data ?? [];
        if (!normalizedSearch) listLoadedAt = Date.now();
      } catch {
        error.value = "历史对话加载失败";
      } finally {
        loading.value = false;
        listRequest = null;
        listRequestSearch = undefined;
      }
    })();
    return listRequest;
  }

  async function open(id: number) {
    loading.value = true;
    error.value = null;
    try {
      const response = await fetchConversation(id);
      if (!response.data.data) throw new Error("对话响应为空");
      current.value = response.data.data;
    } catch (reason) {
      error.value = reason instanceof Error ? reason.message : "对话加载失败";
      throw reason;
    } finally {
      loading.value = false;
    }
  }

  async function loadOlder() {
    if (
      loadingOlder.value ||
      !current.value ||
      !current.value.messages.length ||
      !current.value.messagesTotal
    ) {
      return false;
    }
    const offset = current.value.messagesOffset + current.value.messages.length;
    if (!current.value.hasMoreMessages) return false;
    loadingOlder.value = true;
    try {
      const response = await fetchConversation(current.value.id, offset);
      if (!response.data.data) throw new Error("历史消息响应为空");
      const older = response.data.data;
      current.value = {
        ...current.value,
        messages: [...older.messages, ...current.value.messages],
        messagesOffset: 0,
        hasMoreMessages: older.hasMoreMessages,
        messagesTotal: older.messagesTotal,
      };
      return true;
    } finally {
      loadingOlder.value = false;
    }
  }

  async function create(title?: string) {
    const response = await createConversation(title);
    if (!response.data.data) throw new Error("新建对话响应为空");
    current.value = response.data.data;
    items.value = [toSummary(response.data.data), ...items.value];
    return current.value;
  }

  async function send(
    content: string,
    messageType: ConversationMessageType = "text",
  ) {
    if (!current.value) await create();
    if (!current.value) throw new Error("当前对话不存在");
    sending.value = true;
    error.value = null;
    try {
      const response = await sendConversationMessage(
        current.value.id,
        content,
        messageType,
      );
      if (!response.data.data) throw new Error("消息响应为空");
      current.value = response.data.data;
      const index = items.value.findIndex(
        (item) => item.id === current.value?.id,
      );
      const summary = toSummary(current.value);
      if (index >= 0) items.value.splice(index, 1, summary);
      else items.value.unshift(summary);
      items.value.sort((a, b) => b.updatedAt.localeCompare(a.updatedAt));
      return current.value;
    } catch (reason) {
      error.value = reason instanceof Error ? reason.message : "消息发送失败";
      throw reason;
    } finally {
      sending.value = false;
    }
  }

  async function streamSend(
    content: string,
    onDelta: (delta: string) => void,
    messageType: ConversationMessageType = "text",
  ) {
    if (!current.value) await create();
    if (!current.value) throw new Error("当前对话不存在");
    sending.value = true;
    generating.value = true;
    activeController = new AbortController();
    error.value = null;
    const startedAt = new Date().toISOString();
    const userMessage = {
      id: -Date.now(),
      role: "user" as const,
      messageType,
      content,
      riskResult: null,
      responseCard: null,
      semantic: null,
      createdAt: startedAt,
    };
    activeUserMessageId = userMessage.id;
    const assistantMessage = {
      id: userMessage.id - 1,
      role: "assistant" as const,
      messageType: "text" as const,
      content: "",
      riskResult: null,
      responseCard: null,
      semantic: null as Record<string, unknown> | null,
      createdAt: startedAt,
    };
    current.value = {
      ...current.value,
      messages: [...current.value.messages, userMessage, assistantMessage],
      messageCount: current.value.messageCount + 2,
      messagesTotal: current.value.messagesTotal + 2,
    };
    try {
      const conversationId = current.value.id;
      await streamConversationMessage(
        conversationId,
        content,
        (event) => {
          if (
            event.type === "start" &&
            event.data &&
            typeof event.data === "object" &&
            "messageId" in event.data &&
            typeof event.data.messageId === "number" &&
            current.value
          ) {
            const serverMessageId = event.data.messageId;
            const messages = current.value.messages.map((message) =>
              message.id === userMessage.id
                ? { ...message, id: serverMessageId }
                : message,
            );
            activeUserMessageId = serverMessageId;
            current.value = { ...current.value, messages };
          }
          if (event.type === "delta" && event.content) onDelta(event.content);
          if (event.type === "semantic" && event.data && current.value) {
            const messages = [...current.value.messages];
            const last = messages[messages.length - 1];
            if (last?.role === "assistant") {
              messages[messages.length - 1] = {
                ...last,
                semantic: event.data as Record<string, unknown>,
              };
              current.value = { ...current.value, messages };
            }
          }
          if (event.type === "delta" && event.content && current.value) {
            const messages = [...current.value.messages];
            const last = messages[messages.length - 1];
            if (last?.role === "assistant") {
              messages[messages.length - 1] = {
                ...last,
                content: last.content + event.content,
              };
              current.value = { ...current.value, messages };
            }
          }
          if (event.type === "error")
            throw new Error(event.message || "AI 回复失败");
          if (event.type === "done" && event.data)
            current.value = event.data as Conversation;
        },
        messageType,
        activeController.signal,
      );
      if (
        !current.value ||
        !current.value.messages.some(
          (message) => message.role === "assistant" && message.content.trim(),
        )
      ) {
        throw new Error("AI 回复为空");
      }
      const summary = toSummary(current.value);
      const index = items.value.findIndex((item) => item.id === summary.id);
      if (index >= 0) items.value.splice(index, 1, summary);
      else items.value.unshift(summary);
      return current.value;
    } catch (reason) {
      const conversationId = current.value?.id;
      if (activeController?.signal.aborted) {
        if (conversationId) {
          try {
            const response = await fetchConversation(conversationId);
            if (response.data.data) current.value = response.data.data;
          } catch {
            // If the request was cancelled before persistence, remove both
            // temporary messages from the local conversation.
            if (current.value) {
              const messages = current.value.messages.filter(
                (message) =>
                  message.id !== assistantMessage.id &&
                  message.id !== userMessage.id,
              );
              current.value = {
                ...current.value,
                messages,
                messageCount: Math.max(0, current.value.messageCount - 2),
                messagesTotal: Math.max(0, current.value.messagesTotal - 2),
              };
            }
          }
          const summary = current.value ? toSummary(current.value) : null;
          if (summary) {
            const index = items.value.findIndex(
              (item) => item.id === summary.id,
            );
            if (index >= 0) items.value.splice(index, 1, summary);
            else items.value.unshift(summary);
          }
        }
        return current.value;
      }
      if (current.value) {
        const messages = current.value.messages.filter(
          (message) =>
            message.id !== assistantMessage.id && message.id !== userMessage.id,
        );
        current.value = {
          ...current.value,
          messages,
          messageCount: Math.max(0, current.value.messageCount - 2),
          messagesTotal: Math.max(0, current.value.messagesTotal - 2),
        };
      }
      if (conversationId) {
        try {
          const response = await fetchConversation(conversationId);
          if (response.data.data) current.value = response.data.data;
        } catch {
          // Keep the local state when recovery is unavailable.
        }
      }
      error.value = reason instanceof Error ? reason.message : "AI 回复失败";
      throw reason;
    } finally {
      sending.value = false;
      generating.value = false;
      activeController = null;
      activeUserMessageId = null;
    }
  }

  function stopGeneration() {
    activeController?.abort();
  }

  function isGeneratingMessage(messageId: number) {
    return activeUserMessageId === messageId && generating.value;
  }

  async function withdraw(messageId: number) {
    if (!current.value) return;
    loading.value = true;
    error.value = null;
    try {
      const response = await withdrawConversationMessage(
        current.value.id,
        messageId,
      );
      if (!response.data.data) throw new Error("撤回响应为空");
      current.value = response.data.data;
      const index = items.value.findIndex(
        (item) => item.id === current.value?.id,
      );
      const summary = toSummary(current.value);
      if (index >= 0) items.value.splice(index, 1, summary);
      else items.value.unshift(summary);
      return current.value;
    } catch (reason) {
      error.value = reason instanceof Error ? reason.message : "撤回失败";
      throw reason;
    } finally {
      loading.value = false;
    }
  }

  function reset() {
    current.value = null;
    error.value = null;
  }

  function toSummary(conversation: Conversation): ConversationSummary {
    return {
      id: conversation.id,
      title: conversation.title,
      messageCount: conversation.messageCount,
      lastRiskLevel: conversation.lastRiskLevel,
      updatedAt: conversation.updatedAt,
    };
  }

  return {
    items,
    current,
    loading,
    sending,
    generating,
    loadingOlder,
    error,
    loadList,
    open,
    loadOlder,
    create,
    send,
    streamSend,
    stopGeneration,
    isGeneratingMessage,
    withdraw,
    reset,
  };
});