import { h } from 'koishi';
import { IIROSE_Bot } from '../bot/bot';

export async function clearMsg(msg: string, bot: IIROSE_Bot)
{
    // 处理 markdown 元素：移除开头的 `\\\\\\*\n` 前缀
    // 处理 markdown 元素：移除开头的 `\\\*\n` (即 \\\*\n) 前缀
    // IIROSE 发送的原始消息中，反斜杠被编码为 HTML 实体
    msg = msg.replace(/^(?:\){3}\*\n\s*/, '');

    // 处理 a 元素：移除开头的反斜杠
    msg = msg.replace(/\\(https*:\/\/[\s\S]+)/g, '$1');

    // 优先处理历史遗留的图片格式 `[url#e]`，将其转换为裸链接
    msg = msg.replace(/\[((https*:\/\/[\s\S]+?\.(png|jpg|jpeg|gif))(#e)*)\]/g, '$1');

    async function replaceAsync(str: string, regex: RegExp, asyncFn: (...args: any[]) => Promise<string>)
    {
        const promises: Promise<string>[] = [];
        str.replace(regex, (...args) =>
        {
            promises.push(asyncFn(...args));
            return '';
        });
        const data = await Promise.all(promises);
        return str.replace(regex, () => data.shift()!);
    }

    // 处理图片 (同步)
    const imageUrlRegex = /((?:https?:\/\/[\s\S]+?)\.(?:png|jpg|jpeg|gif)(?:#e)?)/g;
    msg = msg.replace(imageUrlRegex, (match) =>
    {
        const cleanUrl = match.replace(/#e$/, '');
        return h.image(cleanUrl).toString();
    });

    // 处理音频 (同步)
    const audioUrlRegex = /((?:https?:\/\/[\s\S]+?)\.weba)/g;
    msg = msg.replace(audioUrlRegex, (match) =>
    {
        // 将 .weba 结尾的链接转换为 audio 元素
        return h.audio(match).toString();
    });

    // 处理视频 (同步)
    const videoUrlRegex = /\[((?:https?:\/\/[\s\S]+?)\.(?:mp4|webm|ogg))\]/g;
    msg = msg.replace(videoUrlRegex, (match, url) =>
    {
        // 将 [url.mp4] 格式转换为 video 元素
        return h.video(url).toString();
    });

    // 处理 at-by-name (异步)
    // 消耗前后空格，但将空格捕获以便在替换时放回
    // 匹配一个或多个前导空格，以便在消息开头正确处理 at
    const atNameRegex = /(\s+)((?:\[\*[\s\S]+?\*\])+)(\s)/g;
    msg = await replaceAsync(msg, atNameRegex, async (raw, space1, mentionBlock, space2, offset, originalString) =>
    {
        const name = mentionBlock.slice(2, -2);
        const isMultiBlock = mentionBlock.lastIndexOf('[*') > 0;

        const user = await bot.internal.getUserByName(name);
        // 如果 at 元素位于消息开头（或只由空格开头），则不保留前面的空格
        const leadingSpace = (offset === 0 || originalString.substring(0, offset).trim() === '') ? '' : space1;

        if (user)
        {
            return `${leadingSpace}${h('at', { id: user.id, name }).toString()}${space2}`;
        }
        else if (isMultiBlock)
        {
            return `${leadingSpace}${h('at', { id: 'error', name }).toString()}${space2}`;
        }
        return raw;
    });

    // 处理 at-by-id (异步)
    const atIdRegex = /(\s+)((?:\[@[\s\S]+?@\])+)(\s)/g;
    msg = await replaceAsync(msg, atIdRegex, async (raw, space1, mentionBlock, space2, offset, originalString) =>
    {
        const id = mentionBlock.slice(2, -2);
        const isMultiBlock = mentionBlock.lastIndexOf('[@') > 0;

        const user = await bot.getUser(id);
        // 如果 at 元素位于消息开头（或只由空格开头），则不保留前面的空格
        const leadingSpace = (offset === 0 || originalString.substring(0, offset).trim() === '') ? '' : space1;

        if (user)
        {
            return `${leadingSpace}${h('at', { id, name: user.name }).toString()}${space2}`;
        }
        else if (isMultiBlock)
        {
            return `${leadingSpace}${h('at', { id: 'error', name: id }).toString()}${space2}`;
        }
        return raw;
    });

    // 处理 sharp 元素（提及频道）
    const sharpRegex = /(\s+)((?:\[_[\s\S]+?_\])+)(\s)/g;
    msg = await replaceAsync(msg, sharpRegex, async (raw, space1, mentionBlock, space2, offset, originalString) =>
    {
        // 如果 sharp 元素位于消息开头（或只由空格开头），则不保留前面的空格
        const leadingSpace = (offset === 0 || originalString.substring(0, offset).trim() === '') ? '' : space1;
        const channelId = mentionBlock.slice(2, -2);
        // 移除频道ID末尾的下划线
        const cleanChannelId = channelId.replace(/_+$/, '');
        return `${leadingSpace}${h('sharp', { id: cleanChannelId }).toString()}${space2}`;
    });

    return msg;
}