#!/usr/bin/env node

/* eslint-disable */

const jwt = require('jsonwebtoken');
const github = require('@octokit/rest')();
const prettyBytes = require('pretty-bytes');
const fs = require('fs');
const {execSync} = require('child_process');
const zlib = require('zlib');

const SIZE_CHECK_APP_ID = 14028;
const SIZE_CHECK_APP_INSTALLATION_ID = 229425;

const file = process.argv[2];
const label = process.argv[3];
const name = `Size - ${label}`;

if (!file || !label) {
    console.log(`Usage: ${process.argv[0]} ${process.argv[1]} FILE LABEL`);
    process.exit(1);
}

const {size} = fs.statSync(file);
const gzipSize = zlib.gzipSync(fs.readFileSync(file)).length;

process.on('unhandledRejection', error => {
    // don't log `error` directly, because errors from child_process.execSync
    // contain an (undocumented) `envPairs` with environment variable values
    console.log(error.message || 'Error');
    process.exit(1)
});

const pk = process.env['SIZE_CHECK_APP_PRIVATE_KEY'];
if (!pk) {
    console.log('Fork PR; not computing size.');
    process.exit(0);
}

const key = Buffer.from(pk, 'base64').toString('binary');
const payload = {
    exp: Math.floor(Date.now() / 1000) + 60,
    iat: Math.floor(Date.now() / 1000),
    iss: SIZE_CHECK_APP_ID
};

const token = jwt.sign(payload, key, {algorithm: 'RS256'});
github.authenticate({type: 'app', token});

function getMergeBase() {
    const pr = process.env['CIRCLE_PULL_REQUEST'];
    if (pr) {
        const number = +pr.match(/\/(\d+)\/?$/)[1];
        return github.pullRequests.get({
            owner: 'mapbox',
            repo: 'mapbox-gl-js',
            pull_number: number
        }).then(({data}) => {
            const base = data.base.ref;
            const head = process.env['CIRCLE_SHA1'];
            return execSync(`git merge-base origin/${base} ${head}`).toString().trim();
        });
    } else {
        // Walk backward through the history (maximum of 10 commits) until
        // finding a commit on either main or release-*; assume that's the
        // base branch.
        const head = process.env['CIRCLE_SHA1'];
        for (const sha of execSync(`git rev-list --max-count=10 ${head}`).toString().trim().split('\n')) {
            const base = execSync(`git branch -r --contains ${sha} origin/main origin/release-* origin/publisher-production`).toString().split('\n')[0].trim().replace(/^origin\//, '');
            if (base) {
                return Promise.resolve(execSync(`git merge-base origin/${base} ${head}`).toString().trim());
            }
        }
    }

    return Promise.resolve(null);
}

function getPriorSize(mergeBase) {
    if (!mergeBase) {
        console.log('No merge base available.');
        return Promise.resolve(null);
    }

    return github.checks.listForRef({
        owner: 'mapbox',
        repo: 'mapbox-gl-js',
        ref: mergeBase
    }).then(({data}) => {
        const run = data.check_runs.find(run => run.name === name);
        if (run) {
            const match = run.output.summary.match(/`[^`]+` is (\d+) bytes \([^\)]+\) uncompressed, (\d+) bytes \([^\)]+\) gzipped\./);
            if (match) {
                const prior = { size: +match[1], gzipSize: +match[2] };
                console.log(`Prior size was ${prettyBytes(prior.size)}, gzipped ${prior.gzipSize}.`);
                return prior;
            }
        }
        console.log('No matching check found.');
        return Promise.resolve(null);
    });
}

function formatSize(size, priorSize) {
    if (priorSize) {
        const change = size - priorSize;
        const percent = (change / priorSize) * 100;
        return `${change >= 0 ? '+' : ''}${prettyBytes(change)} ${percent.toFixed(3)}% (${prettyBytes(size)})`;
    } else {
        return prettyBytes(size);
    }
}

github.apps.createInstallationToken({installation_id: SIZE_CHECK_APP_INSTALLATION_ID})
    .then(({data}) => {
        github.authenticate({type: 'token', token: data.token});
        getMergeBase().then(getPriorSize).then(prior => {
            const title = `${formatSize(size, prior ? prior.size : null)}, gzipped ${formatSize(gzipSize, prior ? prior.gzipSize : null)}`;

            const megabit = Math.pow(2, 12);
            const downloadTime3G = (gzipSize / (3 * megabit)).toFixed(0);
            const downloadTime4G = (gzipSize / (10 * megabit)).toFixed(0);
            const summary = `\`${file}\` is ${size} bytes (${prettyBytes(size)}) uncompressed, ${gzipSize} bytes (${prettyBytes(gzipSize)}) gzipped.
That's **${downloadTime3G} seconds** over slow 3G (3 Mbps), **${downloadTime4G} seconds** over fast 4G (10 Mbps).`;

            console.log(`Posting check result:\n${title}\n${summary}`);

            return github.checks.create({
                owner: 'mapbox',
                repo: 'mapbox-gl-js',
                name,
                head_branch: process.env['CIRCLE_BRANCH'],
                head_sha: process.env['CIRCLE_SHA1'],
                status: 'completed',
                conclusion: 'success',
                completed_at: new Date().toISOString(),
                output: { title, summary }
            });
        })
    });
