#!/usr/bin/env bun

interface GitHubIssue {
	number: number;
	title: string;
	user: { id: number };
	created_at: string;
}

interface GitHubComment {
	id: number;
	body: string;
	created_at: string;
	user: { type: string; id: number };
}

interface GitHubReaction {
	user: { id: number };
	content: string;
}

async function githubRequest<T>(endpoint: string, token: string, method: string = 'GET', body?: any): Promise<T> {
	const response = await fetch(`https://api.github.com${endpoint}`, {
		method,
		headers: {
			'Authorization': `Bearer ${token}`,
			'Accept': 'application/vnd.github.v3+json',
			'User-Agent': 'auto-close-duplicates-script',
			...(body && { 'Content-Type': 'application/json' }),
		},
		...(body && { body: JSON.stringify(body) }),
	});

	if (!response.ok) {
		throw new Error(`GitHub API request failed: ${response.status} ${response.statusText}`);
	}

	return response.json();
}

function extractDuplicateIssueNumber(commentBody: string): number | null {
	// Try to match #123 format first
	let match = commentBody.match(/#(\d+)/);
	if (match) {
		return parseInt(match[1], 10);
	}

	// Try to match GitHub issue URL format: https://github.com/owner/repo/issues/123
	match = commentBody.match(/github\.com\/[^\/]+\/[^\/]+\/issues\/(\d+)/);
	if (match) {
		return parseInt(match[1], 10);
	}

	return null;
}

async function closeIssueAsDuplicate(
	owner: string,
	repo: string,
	issueNumber: number,
	duplicateOfNumber: number,
	token: string,
): Promise<void> {
	await githubRequest(`/repos/${owner}/${repo}/issues/${issueNumber}`, token, 'PATCH', {
		state: 'closed',
		state_reason: 'duplicate',
		labels: ['duplicate'],
	});

	await githubRequest(`/repos/${owner}/${repo}/issues/${issueNumber}/comments`, token, 'POST', {
		body: `This issue has been automatically closed as a duplicate of #${duplicateOfNumber}.
  
  If this is incorrect, please re-open this issue or create a new one.
  
  🤖 Generated with [Claude Code](https://claude.ai/code)`,
	});
}

async function autoCloseDuplicates(): Promise<void> {
	console.log('[DEBUG] Starting auto-close duplicates script');

	const token = process.env.GITHUB_TOKEN;
	if (!token) {
		throw new Error('GITHUB_TOKEN environment variable is required');
	}
	console.log('[DEBUG] GitHub token found');

	const owner = process.env.GITHUB_REPOSITORY_OWNER || 'RocketChat';
	const repo = process.env.GITHUB_REPOSITORY_NAME || 'Rocket.Chat';
	console.log(`[DEBUG] Repository: ${owner}/${repo}`);

	const threeDaysAgo = new Date();
	threeDaysAgo.setDate(threeDaysAgo.getDate() - 3);
	console.log(`[DEBUG] Checking for duplicate comments older than: ${threeDaysAgo.toISOString()}`);

	console.log('[DEBUG] Fetching open issues created more than 3 days ago...');
	const allIssues: GitHubIssue[] = [];
	let page = 1;
	const perPage = 100;

	while (true) {
		const pageIssues: GitHubIssue[] = await githubRequest(
			`/repos/${owner}/${repo}/issues?state=open&per_page=${perPage}&page=${page}`,
			token,
		);

		if (pageIssues.length === 0) break;

		// Filter for issues created more than 3 days ago
		const oldEnoughIssues = pageIssues.filter((issue) => new Date(issue.created_at) <= threeDaysAgo);

		allIssues.push(...oldEnoughIssues);
		page++;

		// Safety limit to avoid infinite loops
		if (page > 20) break;
	}

	const issues = allIssues;
	console.log(`[DEBUG] Found ${issues.length} open issues`);

	let processedCount = 0;
	let candidateCount = 0;

	for (const issue of issues) {
		processedCount++;
		console.log(`[DEBUG] Processing issue #${issue.number} (${processedCount}/${issues.length}): ${issue.title}`);

		console.log(`[DEBUG] Fetching comments for issue #${issue.number}...`);
		const comments: GitHubComment[] = await githubRequest(`/repos/${owner}/${repo}/issues/${issue.number}/comments`, token);
		console.log(`[DEBUG] Issue #${issue.number} has ${comments.length} comments`);

		const dupeComments = comments.filter(
			(comment) => comment.body.includes('Found') && comment.body.includes('possible duplicate') && comment.user.type === 'Bot',
		);
		console.log(`[DEBUG] Issue #${issue.number} has ${dupeComments.length} duplicate detection comments`);

		if (dupeComments.length === 0) {
			console.log(`[DEBUG] Issue #${issue.number} - no duplicate comments found, skipping`);
			continue;
		}

		const lastDupeComment = dupeComments[dupeComments.length - 1];
		const dupeCommentDate = new Date(lastDupeComment.created_at);
		console.log(`[DEBUG] Issue #${issue.number} - most recent duplicate comment from: ${dupeCommentDate.toISOString()}`);

		if (dupeCommentDate > threeDaysAgo) {
			console.log(`[DEBUG] Issue #${issue.number} - duplicate comment is too recent, skipping`);
			continue;
		}
		console.log(
			`[DEBUG] Issue #${issue.number} - duplicate comment is old enough (${Math.floor(
				(Date.now() - dupeCommentDate.getTime()) / (1000 * 60 * 60 * 24),
			)} days)`,
		);

		const commentsAfterDupe = comments.filter((comment) => new Date(comment.created_at) > dupeCommentDate);
		console.log(`[DEBUG] Issue #${issue.number} - ${commentsAfterDupe.length} comments after duplicate detection`);

		if (commentsAfterDupe.length > 0) {
			console.log(`[DEBUG] Issue #${issue.number} - has activity after duplicate comment, skipping`);
			continue;
		}

		console.log(`[DEBUG] Issue #${issue.number} - checking reactions on duplicate comment...`);
		const reactions: GitHubReaction[] = await githubRequest(
			`/repos/${owner}/${repo}/issues/comments/${lastDupeComment.id}/reactions`,
			token,
		);
		console.log(`[DEBUG] Issue #${issue.number} - duplicate comment has ${reactions.length} reactions`);

		const authorThumbsDown = reactions.some((reaction) => reaction.user.id === issue.user.id && reaction.content === '-1');
		console.log(`[DEBUG] Issue #${issue.number} - author thumbs down reaction: ${authorThumbsDown}`);

		if (authorThumbsDown) {
			console.log(`[DEBUG] Issue #${issue.number} - author disagreed with duplicate detection, skipping`);
			continue;
		}

		const duplicateIssueNumber = extractDuplicateIssueNumber(lastDupeComment.body);
		if (!duplicateIssueNumber) {
			console.log(`[DEBUG] Issue #${issue.number} - could not extract duplicate issue number from comment, skipping`);
			continue;
		}

		candidateCount++;
		const issueUrl = `https://github.com/${owner}/${repo}/issues/${issue.number}`;

		try {
			console.log(`[INFO] Auto-closing issue #${issue.number} as duplicate of #${duplicateIssueNumber}: ${issueUrl}`);
			await closeIssueAsDuplicate(owner, repo, issue.number, duplicateIssueNumber, token);
			console.log(`[SUCCESS] Successfully closed issue #${issue.number} as duplicate of #${duplicateIssueNumber}`);
		} catch (error) {
			console.error(`[ERROR] Failed to close issue #${issue.number} as duplicate: ${error}`);
		}
	}

	console.log(`[DEBUG] Script completed. Processed ${processedCount} issues, found ${candidateCount} candidates for auto-close`);
}

autoCloseDuplicates().catch(console.error);

// Make it a module
export {};