import { SUBS_KEY, COLLECTIONS_KEY } from './constants';
import { produceArtifact } from './artifacts';
import $ from '../core/app';

export default function register($app) {
    if (!$.read(SUBS_KEY)) $.write({}, SUBS_KEY);

    $app.get('/download/:name', downloadSubscription);

    $app.route('/api/sub/:name')
        .get(getSubscription)
        .patch(updateSubscription)
        .delete(deleteSubscription);

    $app.route('/api/subs').get(getAllSubscriptions).post(createSubscription);
}

// subscriptions API
async function downloadSubscription(req, res) {
    const { name } = req.params;
    const { raw } = req.query || 'false';
    const platform =
        req.query.target || getPlatformFromHeaders(req.headers) || 'JSON';

    $.info(`正在下载订阅：${name}`);

    const allSubs = $.read(SUBS_KEY);
    const sub = allSubs[name];
    if (sub) {
        try {
            const output = await produceArtifact({
                type: 'subscription',
                item: sub,
                platform,
                noProcessor: raw,
            });

            // forward flow headers
            const flowInfo = await getFlowHeaders(sub.url);
            if (flowInfo) {
                res.set('subscription-userinfo', flowInfo);
            }

            if (platform === 'JSON') {
                res.set('Content-Type', 'application/json;charset=utf-8').send(
                    output,
                );
            } else {
                res.send(output);
            }
        } catch (err) {
            $.notify(
                `🌍 『 𝑺𝒖𝒃-𝑺𝒕𝒐𝒓𝒆 』 下载订阅失败`,
                `❌ 无法下载订阅：${name}！`,
                `🤔 原因：${JSON.stringify(err)}`,
            );
            $.error(JSON.stringify(err));
            res.status(500).json({
                status: 'failed',
                message: err,
            });
        }
    } else {
        $.notify(`🌍 『 𝑺𝒖𝒃-𝑺𝒕𝒐𝒓𝒆 』 下载订阅失败`, `❌ 未找到订阅：${name}！`);
        res.status(404).json({
            status: 'failed',
        });
    }
}

function createSubscription(req, res) {
    const sub = req.body;
    const allSubs = $.read(SUBS_KEY);
    $.info(`正在创建订阅： ${sub.name}`);
    if (allSubs[sub.name]) {
        res.status(500).json({
            status: 'failed',
            message: `订阅${sub.name}已存在！`,
        });
    }
    // validate name
    if (/^[\w-_]*$/.test(sub.name)) {
        allSubs[sub.name] = sub;
        $.write(allSubs, SUBS_KEY);
        res.status(201).json({
            status: 'success',
            data: sub,
        });
    } else {
        res.status(500).json({
            status: 'failed',
            message: `订阅名称 ${sub.name} 中含有非法字符！名称中只能包含英文字母、数字、下划线、横杠。`,
        });
    }
}

function getSubscription(req, res) {
    const { name } = req.params;
    const sub = $.read(SUBS_KEY)[name];
    if (sub) {
        res.json({
            status: 'success',
            data: sub,
        });
    } else {
        res.status(404).json({
            status: 'failed',
            message: `未找到订阅：${name}!`,
        });
    }
}

function updateSubscription(req, res) {
    const { name } = req.params;
    let sub = req.body;
    const allSubs = $.read(SUBS_KEY);
    if (allSubs[name]) {
        const newSub = {
            ...allSubs[name],
            ...sub,
        };
        $.info(`正在更新订阅： ${name}`);
        // allow users to update the subscription name
        if (name !== sub.name) {
            // we need to find out all collections refer to this name
            const allCols = $.read(COLLECTIONS_KEY);
            for (const k of Object.keys(allCols)) {
                const idx = allCols[k].subscriptions.indexOf(name);
                if (idx !== -1) {
                    allCols[k].subscriptions[idx] = sub.name;
                }
            }
            // update subscriptions
            delete allSubs[name];
            allSubs[sub.name] = newSub;
        } else {
            allSubs[name] = newSub;
        }
        $.write(allSubs, SUBS_KEY);
        res.json({
            status: 'success',
            data: newSub,
        });
    } else {
        res.status(500).json({
            status: 'failed',
            message: `订阅${name}不存在，无法更新！`,
        });
    }
}

function deleteSubscription(req, res) {
    const { name } = req.params;
    $.info(`删除订阅：${name}...`);
    // delete from subscriptions
    let allSubs = $.read(SUBS_KEY);
    delete allSubs[name];
    $.write(allSubs, SUBS_KEY);
    // delete from collections
    let allCols = $.read(COLLECTIONS_KEY);
    for (const k of Object.keys(allCols)) {
        allCols[k].subscriptions = allCols[k].subscriptions.filter(
            (s) => s !== name,
        );
    }
    $.write(allCols, COLLECTIONS_KEY);
    res.json({
        status: 'success',
    });
}

function getAllSubscriptions(req, res) {
    const allSubs = $.read(SUBS_KEY);
    res.json({
        status: 'success',
        data: allSubs,
    });
}

export async function getFlowHeaders(url) {
    const { headers } = await $.http.get({
        url,
        headers: {
            'User-Agent': 'Quantumult%20X/1.0.30 (iPhone14,2; iOS 15.6)',
        },
    });
    const subkey = Object.keys(headers).filter((k) =>
        /SUBSCRIPTION-USERINFO/i.test(k),
    )[0];
    return headers[subkey];
}

export function getPlatformFromHeaders(headers) {
    const keys = Object.keys(headers);
    let UA = '';
    for (let k of keys) {
        if (/USER-AGENT/i.test(k)) {
            UA = headers[k];
            break;
        }
    }
    if (UA.indexOf('Quantumult%20X') !== -1) {
        return 'QX';
    } else if (UA.indexOf('Surge') !== -1) {
        return 'Surge';
    } else if (UA.indexOf('Decar') !== -1 || UA.indexOf('Loon') !== -1) {
        return 'Loon';
    } else if (
        UA.indexOf('Stash') !== -1 ||
        UA.indexOf('Shadowrocket') !== -1
    ) {
        return 'Clash';
    } else {
        return null;
    }
}