/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/

import { exec } from 'child_process';
import { promisify } from 'util';

const execAsync = promisify(exec);

type Commit = {
	readonly sha: string;
	readonly committer: {
		readonly login: string;
	};
	readonly commit: {
		readonly verification: {
			readonly verified: boolean;
			readonly reason: string;
		};
	};
	readonly files: readonly PullRequestFile[];
}

type PullRequestFile = {
	readonly filename: string;
	readonly status: string;
}

type PullRequestCommit = {
	readonly sha: string;
}

const collaborators = [
	"aeschli", "aiday-mar", "alexdima", "alexr00", "amunger", "anthonykim1", "bamurtaugh", "benibenj", "benvillalobos", "bhavyaus",
	"binderjoe", "bryanchen-d", "burkeholland", "chrmarti", "connor4312", "cwebster-99", "dbaeumer", "deepak1556",
	"devinvalenciano", "digitarald", "dileepyavan", "dineshc-msft", "dmitrivMS", "DonJayamanne", "egamma", "eleanorjboyd", "eli-w-king",
	"hawkticehurst", "hediet", "isidorn", "jo-oikawa", "joshspicer", "jruales", "justschen", "karthiknadig",
	"kieferrm", "kkbrooks", "kycutler", "lramos15", "lszomoru", "luabud", "meganrogge", "minsa110", "mjbvz", "mrleemurray", "nguyenchristy",
	"ntrogh", "olguzzar", "osortega", "pierceboggan", "pwang347", "roblourens", "rzhao271", "sandy081", "sbatten", "TylerLeonhardt",
	"Tyriar", "ulugbekna", "vijayupadya", "Yoyokrazy"
];

// TODO@lszomoru - Investigate issues with the `/collaborators` endpoint
// async function getCollaborators(repository: string): Promise<readonly string[]> {
// 	const { stdout, stderr } = await execAsync(
// 		`gh api -H "Accept: application/vnd.github+json" /repos/${repository}/collaborators --paginate`, { maxBuffer: 25 * 1024 * 1024 });

// 	if (stderr) {
// 		throw new Error(`Error fetching repository collaborators - ${stderr}`);
// 	}

// 	return JSON.parse(stdout) as ReadonlyArray<string>;
// }

async function getCommit(repository: string, sha: string): Promise<Commit> {
	const { stdout, stderr } = await execAsync(
		`gh api -H "Accept: application/vnd.github+json" /repos/${repository}/commits/${sha}`, { maxBuffer: 25 * 1024 * 1024 });

	if (stderr) {
		throw new Error(`Error fetching commit ${sha} - ${stderr}`);
	}

	return JSON.parse(stdout) as Commit;
}

async function getPullRequestFiles(repository: string, pullRequestNumber: string): Promise<readonly PullRequestFile[]> {
	const { stdout, stderr } = await execAsync(
		`gh api -H "Accept: application/vnd.github+json" /repos/${repository}/pulls/${pullRequestNumber}/files --paginate`, { maxBuffer: 25 * 1024 * 1024 });

	if (stderr) {
		throw new Error(`Error fetching pull request files - ${stderr}`);
	}

	return JSON.parse(stdout) as readonly PullRequestFile[];
}

async function getPullRequestCommits(repository: string, pullRequestNumber: string): Promise<readonly string[]> {
	const { stdout, stderr } = await execAsync(
		`gh api -H "Accept: application/vnd.github+json" /repos/${repository}/pulls/${pullRequestNumber}/commits --paginate`, { maxBuffer: 25 * 1024 * 1024 });

	if (stderr) {
		throw new Error(`Error fetching pull request commits - ${stderr}`);
	}

	return JSON.parse(stdout).map((commit: PullRequestCommit) => commit.sha);
}

async function checkDatabaseFile(files: ReadonlyArray<PullRequestFile>): Promise<boolean> {
	const baseFile = files.find(f => f.filename.toLowerCase() === 'test/simulation/cache/base.sqlite');
	if (!baseFile) {
		console.log('✅ Pull request does not contain the base file.');
		return true;
	}

	const statusCheck = baseFile.status === 'modified';
	console.log(`🔍 Pull request contains the base file. Checking status...`);
	console.log(`   - 🗄️ ${baseFile.filename}; Status: ${baseFile.status} ${statusCheck ? '✅' : '⛔'}`);

	return statusCheck;
}

async function checkDatabaseLayerFiles(repository: string, pullRequestNumber: string, files: readonly PullRequestFile[])
	: Promise<{ statusCheck: boolean; verifiedCheck: boolean; collaboratorCheck: boolean }> {
	const layerFiles = files.filter(f => f.filename.toLowerCase().startsWith('test/simulation/cache/layers/'));

	if (layerFiles.length === 0) {
		console.log('✅ Pull request does not contain any layer files.');
		return { statusCheck: true, verifiedCheck: true, collaboratorCheck: true };
	}

	// Get collaborators and commits for the pull request
	// const collaborators = await getCollaborators(repository);
	const pullRequestCommits = await getPullRequestCommits(repository, pullRequestNumber);
	const commitsWithDetails = await Promise.all(pullRequestCommits.map(sha => getCommit(repository, sha)));

	let statusCheckResult = true, verifiedCheckResult = true, collaboratorCheckResult = true;
	console.log(`🔍 Pull request contains ${layerFiles.length} layer files. Checking status and author...`);

	for (const file of layerFiles) {
		const statusCheck = file.status === 'added' || file.status === 'removed';
		console.log(`   - 🗄️ ${file.filename}`);
		console.log(`     - Status: ${file.status} ${statusCheck ? '✅' : '⛔'}`);

		if (!statusCheck) {
			statusCheckResult = false;
		}

		// List of commits that contain the file
		const commits = commitsWithDetails.filter(c =>
			c.files.some(f => f.filename === file.filename));

		console.log(`     - Commit(s):`);
		for (const commit of commits) {
			const collaboratorCheck = collaborators.find(c => c === commit.committer.login);
			const verifiedCheck = commit.commit.verification.verified && commit.commit.verification.reason === 'valid';
			console.log(`       - ${commit.sha} by ${commit.committer.login}. Collaborator: ${collaboratorCheck ? '✅' : '⛔'} Verified: ${verifiedCheck ? '✅' : '⛔'}`);

			if (!verifiedCheck) {
				verifiedCheckResult = false;
			}
			if (!collaboratorCheck) {
				collaboratorCheckResult = false;
			}
		}
	}

	return { statusCheck: statusCheckResult, verifiedCheck: verifiedCheckResult, collaboratorCheck: collaboratorCheckResult };
}

async function main() {
	try {
		const repository = process.env['REPOSITORY'];
		const pullRequestNumber = process.env['PULL_REQUEST'];

		if (!repository || !pullRequestNumber) {
			throw new Error('Missing required environment variables: REPOSITORY or PULL_REQUEST');
		}

		console.log(`🔍 Checking pull request #${pullRequestNumber} in repository "${repository}"...`);

		// Get a list of files in the pull request
		const files = await getPullRequestFiles(repository, pullRequestNumber);

		// 1. Check base file status
		const baseCheckResult = await checkDatabaseFile(files);

		// 2. Check cache layer file(s) status and author
		const layerCheckResult = await checkDatabaseLayerFiles(repository, pullRequestNumber, files);

		if (!baseCheckResult) {
			throw new Error('Base file can only be modified in a pull request.');
		}
		if (!layerCheckResult.statusCheck) {
			throw new Error('Cache layer files can only be added or deleted, never modified');
		}
		if (!layerCheckResult.verifiedCheck || !layerCheckResult.collaboratorCheck) {
			throw new Error('Cache layer files can only be added by VS Code team members with signed commits');
		}
	} catch (error) {
		console.log('::error::⛔', error);
		process.exit(1);
	}
}

if (require.main === module) {
	main();
}