// ==UserScript==
// @name         Better GitHub Co-Authors
// @name:zh-CN   GitHub 共同协作者
// @description  Adds a button to GitHub pull requests to make it simple to add co-author credits for all PR participants before merging.
// @description:zh-CN 在 GitHub PR中添加一个按钮,以便在合并之前将所有 PR 参与者添加为共同作者.
// @author       delucis,人民的勤务员 <china.qinwuyuan@gmail.com>
// @namespace    https://github.com/ChinaGodMan/UserScripts
// @supportURL   https://github.com/ChinaGodMan/UserScripts/issues
// @homepageURL  https://github.com/ChinaGodMan/UserScripts
// @license      MIT
// @match        https://github.com/*
// @icon        https://raw.githubusercontent.com/ChinaGodMan/UserScriptsHistory/main/scriptsIcon/github-co-authors.png
// @compatible   chrome
// @compatible   firefox
// @compatible   edge
// @compatible   opera
// @compatible   safari
// @compatible   kiwi
// @compatible   qq
// @compatible   via
// @compatible   brave
// @version      2025.5.27.1
// @grant        GM_setValue
// @grant        GM_getValue
// @downloadURL none
// ==/UserScript==
/**
 * File: github-co-authors.user.js
 * Project: UserScripts
 * File Created: 2025/05/27,Tuesday 22:47:12
 * Author: Chris Swithinbank(swithinbank@gmail.com),人民的勤务员@ChinaGodMan (china.qinwuyuan@gmail.com)
 * -----
 * Last Modified: 2025/05/27,Tuesday 23:16:14
 * Modified By: 人民的勤务员@ChinaGodMan (china.qinwuyuan@gmail.com)
 * -----
 * License: MIT License
 * Copyright © 2024 - 2025 ChinaGodMan,Inc
 */

let GITHUB_TOKEN = GM_getValue('GITHUB_TOKEN', '')
if (!GITHUB_TOKEN) {
    GM_setValue('GITHUB_TOKEN', prompt('Please enter your GitHub Token'))
    GITHUB_TOKEN = GM_getValue('GITHUB_TOKEN', '')
}

// Run the script
addCoAuthorsButtonToMergeForm()
// Re-run the script when navigating between pages
document.addEventListener('turbo:render', addCoAuthorsButtonToMergeForm)

/**
 * Create the UI for adding co-authors.
 * @param {HTMLElement} root
 * @param {Element | null} newMergeExperienceContainer
 */
function createCoAuthorsUI(root, newMergeExperienceContainer) {
    const banner = document.createElement('div')
    banner.setAttribute('aria-live', 'polite')
    banner.classList.add('color-fg-subtle')

    let bannerTimeout
    /**
     * Display a temporary status update about the progress adding co-authors.
     * @param {string} msg The message to display
     * @param {'subtle' | 'success' | 'danger'} color The status color to use.
     */
    const displayStatus = (msg, color = 'subtle') => {
        clearTimeout(bannerTimeout)
        banner.textContent = msg
        banner.className = `color-fg-${color}`
        bannerTimeout = setTimeout(() => (banner.textContent = ''), 5000)
    }

    const button = document.createElement('button')
    button.textContent = 'Add co-authors'
    button.classList.add('Button', 'Button--secondary', 'Button--small')
    button.type = 'button'
    button.addEventListener('click', async () => {
        displayStatus('Loading co-authors…')
        try {
            const { message, count } = await getCoAuthors()
            /** @type {HTMLTextAreaElement | null} */
            const textArea = newMergeExperienceContainer?.querySelector('textarea') ??
                root.querySelector('textarea#merge_message_field')
            if (!textArea) {
                throw new Error('Couldn’t find commit message <textarea>')
            }
            // Append co-authors to textarea content.
            textArea.value = (textArea.value + '\n\n' + message).trim()
            // Notify event listeners that the <textarea> content changed.
            textArea.dispatchEvent(new Event('change', { bubbles: true, cancelable: true }))

            if (count === 0) {
                displayStatus('Found no co-authors to add')
            } else {
                displayStatus(`Added ${count} co-author${count === 1 ? '' : 's'}`, 'success')
            }
        } catch (error) {
            console.error('Error adding co-authors:', error)
            displayStatus('Something went wrong.', 'danger')
        }
    })
    // Build container
    const container = document.createElement('div')
    container.classList.add('d-flex', 'flex-items-center', 'gap-2')
    if (newMergeExperienceContainer) container.classList.add('mt-3')
    container.append(button)
    container.append(banner)
    return container
}

/** Get participants for the current PR and generate `Co-authored-by` messages for them. */
async function getCoAuthors() {
    const [, owner, repo, _pull, id] = window.location.pathname.split('/')
    const pullNumber = parseInt(id || '', 10)

    const [prData, comments, reviewComments, reviews] = await Promise.all([
        fetchGitHubAPI(`/repos/${owner}/${repo}/pulls/${pullNumber}`),
        fetchGitHubAPI(`/repos/${owner}/${repo}/issues/${pullNumber}/comments`),
        fetchGitHubAPI(`/repos/${owner}/${repo}/pulls/${pullNumber}/comments`),
        fetchGitHubAPI(`/repos/${owner}/${repo}/pulls/${pullNumber}/reviews`)
    ])

    const participants = /** @type {Map<string, { name: string; email: string }>} */ (new Map())

    // Add commenters
    for (const { user } of [...comments, ...reviewComments, ...reviews]) {
        // Skip bot comments
        if (user.type === 'Bot') continue
        // Skip PR author
        if (user.login === prData.user.login) continue
        // Add commenters
        if (!participants.has(user.login)) {
            participants.set(user.login, {
                name: user.name || user.login,
                email: `${user.id}+${user.login}@users.noreply.github.com`
            })
        }
    }

    const lines = Array.from(participants.values()).map(
        (p) => `Co-authored-by: ${p.name} <${p.email}>`
    )
    return { message: lines.join('\n'), count: lines.length }
}

/**
 * Simple wrapper around `fetch()` for making GitHub API requests, e.g. `fetchGitHubAPI('/repos/withastro')`.
 * Throws an error if the fetch does not succeed.
 * @param {string} endpoint GitHub API endpoint to fetch
 */
async function fetchGitHubAPI(endpoint) {
    const response = await fetch(`https://api.github.com${endpoint}`, {
        headers: {
            Accept: 'application/vnd.github.v3+json',
            Authorization: `token ${GITHUB_TOKEN}`
        }
    })
    if (!response.ok) {
        throw new Error(`GitHub API request failed: ${response.statusText}`)
    }
    return response.json()
}

/**
 * Create and add the co-authors button.
 * @param {HTMLElement} root Element to search within and add the co-authors button to.
 */
function addCoAuthorsButton(root) {
    const newMergeExperienceContainer = root.querySelector('react-partial[partial-name="mergebox-partial"]')
    const commitTitleInput = newMergeExperienceContainer?.querySelector('div:has(> label):nth-child(1)') ??
        root.querySelector('input[name="commit_title"]')
    if (!commitTitleInput || root.querySelector('[data-coauthors-button]')) {
        return
    }
    const button = createCoAuthorsUI(root, newMergeExperienceContainer)
    button.setAttribute('data-coauthors-button', '')
    commitTitleInput.insertAdjacentElement('afterend', button)
}

/**
 * Look for the PR merge form and add monitor it to add the co-authors button when possible.
 */
function addCoAuthorsButtonToMergeForm() {
    const element = /** @type {HTMLDivElement | null} */ (
        document.querySelector('.discussion-timeline-actions')
    )
    if (!element) return

    const observer = new MutationObserver(() => {
        addCoAuthorsButton(element)
    })
    observer.observe(element, { subtree: true, childList: true })
    addCoAuthorsButton(element)
}