import request from "@/utils/request";
import { PREFIX_BASE_URL, TOKEN_HEADER_NAME } from "@/config/setting";
import { getToken } from "@/utils/token-util";

export const getAiRuntime = async (promptCode = "home.default", sessionId = null) => {
    const res = await request.get("ai/chat/runtime", {
        params: { promptCode, sessionId },
    });
    const { code, msg, data } = res.data;
    if (code === 200) {
        return data;
    }
    throw new Error(msg || "获取 AI 运行时信息失败");
};

export const getAiSessions = async (promptCode = "home.default", keyword = "") => {
    const res = await request.get("ai/chat/sessions", {
        params: { promptCode, keyword },
    });
    const { code, msg, data } = res.data;
    if (code === 200) {
        return data || [];
    }
    throw new Error(msg || "获取 AI 会话列表失败");
};

export const removeAiSession = async (sessionId) => {
    const res = await request.post(`ai/chat/session/remove/${sessionId}`);
    const { code, msg, data } = res.data;
    if (code === 200) {
        return data;
    }
    throw new Error(msg || "删除 AI 会话失败");
};

export const renameAiSession = async (sessionId, title) => {
    const res = await request.post(`ai/chat/session/rename/${sessionId}`, { title });
    const { code, msg, data } = res.data;
    if (code === 200) {
        return data;
    }
    throw new Error(msg || "重命名 AI 会话失败");
};

export const pinAiSession = async (sessionId, pinned) => {
    const res = await request.post(`ai/chat/session/pin/${sessionId}`, { pinned });
    const { code, msg, data } = res.data;
    if (code === 200) {
        return data;
    }
    throw new Error(msg || "更新 AI 会话置顶状态失败");
};

export const clearAiSessionMemory = async (sessionId) => {
    const res = await request.post(`ai/chat/session/memory/clear/${sessionId}`);
    const { code, msg, data } = res.data;
    if (code === 200) {
        return data;
    }
    throw new Error(msg || "清空 AI 会话记忆失败");
};

export const retainAiSessionLatestRound = async (sessionId) => {
    const res = await request.post(`ai/chat/session/memory/retain-latest/${sessionId}`);
    const { code, msg, data } = res.data;
    if (code === 200) {
        return data;
    }
    throw new Error(msg || "仅保留当前轮记忆失败");
};

export const streamAiChat = async (payload, { signal, onEvent } = {}) => {
    const token = getToken();
    const response = await fetch(`${PREFIX_BASE_URL}ai/chat/stream`, {
        method: "POST",
        headers: {
            "Content-Type": "application/json",
            "Accept": "text/event-stream",
            ...(token ? { [TOKEN_HEADER_NAME]: token } : {}),
        },
        body: JSON.stringify(payload),
        signal,
    });

    if (!response.ok) {
        throw new Error(`AI 请求失败 (${response.status})`);
    }
    if (!response.body) {
        throw new Error("AI 响应流不可用");
    }

    const reader = response.body.getReader();
    const decoder = new TextDecoder("utf-8");
    let buffer = "";

    while (true) {
        const { done, value } = await reader.read();
        if (done) {
            break;
        }
        buffer += decoder.decode(value, { stream: true });
        const events = buffer.split(/\r?\n\r?\n/);
        buffer = events.pop() || "";
        events.forEach((item) => dispatchSseEvent(item, onEvent));
    }

    if (buffer.trim()) {
        dispatchSseEvent(buffer, onEvent);
    }
};

const dispatchSseEvent = (rawEvent, onEvent) => {
    const lines = rawEvent.split(/\r?\n/);
    let eventName = "message";
    const dataLines = [];

    lines.forEach((line) => {
        if (line.startsWith("event:")) {
            eventName = line.slice(6).trim();
        }
        if (line.startsWith("data:")) {
            dataLines.push(line.slice(5).trim());
        }
    });

    if (!dataLines.length) {
        return;
    }

    const rawData = dataLines.join("\n");
    let payload = rawData;
    try {
        payload = JSON.parse(rawData);
    } catch (error) {
    }
    if (onEvent) {
        onEvent(eventName, payload);
    }
};