"use client";
import { REQUEST_TIMEOUT_MS } from "@/app/constant";
import { useChatStore } from "@/app/store";
import {
  ChatOptions,
  LLMApi,
  LLMModel,
} from "../api";
import Locale from "../../locales";
import {
  EventStreamContentType,
  fetchEventSource,
} from "@fortaine/fetch-event-source";
import { prettyObject } from "@/app/utils/format";
import { getMessageTextContent } from "@/app/utils";
import { bigModelApiKey, knowledgeId, template } from "../config";

export class BigModelApi implements LLMApi {
  public useApi: 'public' | 'private';
  public publicPath: string;
  public privatePath: string;

  constructor() {
    this.useApi = 'private';
    this.publicPath = 'https://open.bigmodel.cn/api/paas/v4/chat/completions';
    // 配置私有请求地址
    this.privatePath = 'https://open.bigmodel.cn/api/llm-application/open/model-api/1828613766624038913/sse-invoke';
  }

  async chat(options: ChatOptions) {
    const messages = options.messages.map((item) => {
      return {
        role: item.role,
        content: getMessageTextContent(item),
      }
    });

    const userMessages = messages.filter(item => item.content);

    if (userMessages.length % 2 === 0) {
      userMessages.unshift({
        role: "user",
        content: "⠀",
      });
    }

    // 开放大模型参数
    const publicParams: any = {
      messages: userMessages,
      stream: true,// 流式回复
      model: 'glm-4-0520',// 模型
      temperature: 0.01,// 采样温度
      top_p: 0.7,// 核取样
      // 进阶配置
      tools: [
        {
          type: 'retrieval', // 工具类型为检索
          retrieval: {
            // 知识库ID
            knowledge_id: knowledgeId,
            // 知识库模板
            prompt_template: template.content,
          },
        },
      ],
    };

    // 私有大模型参数
    const privateParams: any = {
      prompt: userMessages,
      // model: 'glm-4-0520',// 模型
      // temperature: 0.01,// 采样温度
      // top_p: 0.7,// 核取样
      // 进阶配置
      request_id: 'jkec2024',
      returnType: undefined,
      knowledge_ids: undefined,
      document_ids: undefined,
    };

    const controller = new AbortController();

    options.onController?.(controller);

    try {
      const chatPath = this.useApi === 'public' ? this.publicPath : this.privatePath;
      const chatPayload = {
        method: "POST",
        body: JSON.stringify(this.useApi === 'public' ? publicParams : privateParams),
        signal: controller.signal,
        headers: {
          'Content-Type': 'application/json',
          // APIKey
          Authorization: bigModelApiKey
        },
      };

      const requestTimeoutId = setTimeout(() => controller.abort(), REQUEST_TIMEOUT_MS);

      let responseText = "";
      let remainText = "";
      let finished = false;

      function animateResponseText() {
        if (finished || controller.signal.aborted) {
          responseText += remainText;
          if (responseText?.length === 0) {
            options.onError?.(new Error("empty response from server"));
          }
          return;
        }

        if (remainText.length > 0) {
          const fetchCount = Math.max(1, Math.round(remainText.length / 60));
          const fetchText = remainText.slice(0, fetchCount);
          responseText += fetchText;
          remainText = remainText.slice(fetchCount);
          options.onUpdate?.(responseText, fetchText);
        }

        requestAnimationFrame(animateResponseText);
      }

      animateResponseText();

      const finish = () => {
        if (!finished) {
          finished = true;
          options.onFinish(responseText + remainText);
        }
      };

      controller.signal.onabort = finish;
      // 记录上次的 remainText
      let previousRemainText = "";
      fetchEventSource(chatPath, {
        ...chatPayload,
        async onopen(res) {
          clearTimeout(requestTimeoutId);
          const contentType = res.headers.get("content-type");

          if (contentType?.startsWith("text/plain")) {
            responseText = await res.clone().text();
            return finish();
          }

          if (
            !res.ok ||
            !res.headers.get("content-type")?.startsWith(EventStreamContentType) ||
            res.status !== 200
          ) {
            const responseTexts = [responseText];
            let extraInfo = await res.clone().text();
            try {
              const resJson = await res.clone().json();
              extraInfo = prettyObject(resJson);
            } catch { }

            if (res.status === 401) {
              responseTexts.push(Locale.Error.Unauthorized);
            }

            if (extraInfo) {
              responseTexts.push(extraInfo);
            }

            responseText = responseTexts.join("\n\n");

            return finish();
          }
        },
        onmessage: (msg) => {
          const handlePublicMessage = () => {
            if (msg.data === "[DONE]" || finished) {
              return finish();
            }
            const text = msg.data;
            try {
              const json = JSON.parse(text);
              const choices = json.choices as Array<{ delta: { content: string } }>;
              const delta = choices[0]?.delta?.content;
              if (delta) {
                remainText += delta;
              }
            } catch (e) {
              console.error("[Request] parse error", text, msg);
            }
          };

          const handlePrivateMessage = () => {
            if (msg.event === 'finish') {
              return finish();
            }
            // 获取当前的数据
            const currentData = msg.data;
            // 计算新增的字符
            const newChars = currentData.substring(previousRemainText.length);
            remainText += newChars;
            // 更新 previousRemainText
            previousRemainText = currentData;
          };

          if (this.useApi === 'public') {
            handlePublicMessage();
          } else {
            handlePrivateMessage();
          }
        },
        async onclose() {
          finish();
          const session = useChatStore.getState().sessions[0];
          const data = {
            id: session.id,
            messages: session.messages.map(item => ({
              id: item.id,
              date: item.date,
              role: item.role,
              content: item.content,
            })),
          };
          await fetch('/api/bigModel', {
            method: 'POST',
            body: JSON.stringify(data),
          });
        },
        onerror(e) {
          options.onError?.(e);
          throw e;
        },
        openWhenHidden: true,
      });
    } catch (e) {
      options.onError?.(e as Error);
    }
  }

  async usage() {
    return {
      used: 0,
      total: 0,
    };
  }

  async models(): Promise<LLMModel[]> {
    return [];
  }
}