/**
 * Webhook server — receives Gitea events via HTTP
 *
 * Auth: Bearer token validation (PI_WEBHOOK_TOKEN).
 * No HMAC/secret — consistent with token-based auth strategy.
 */

import type { Server, IncomingMessage, ServerResponse } from "node:http";
import type { ExtensionAPI } from "@mariozechner/pi-coding-agent";
import { GiteaClient } from "../../src/client.js";

const WEBHOOK_HOST = process.env.PI_WEBHOOK_HOST ?? "0.0.0.0";
const WEBHOOK_PORT = parseInt(process.env.PI_WEBHOOK_PORT ?? "3000", 10);
const WEBHOOK_TOKEN = process.env.PI_WEBHOOK_TOKEN ?? "";
const WEBHOOK_URL = process.env.PI_WEBHOOK_URL ?? "";
const POLL_INTERVAL = parseInt(process.env.PI_BOT_POLL_INTERVAL ?? "300", 10);

let server: Server | null = null;
let trackedRepos: Map<string, { webhookId: number; addedAt: number }> = new Map();
let processingQueue: Array<{ event: any; timestamp: number }> = [];
let maxQueueDepth = 50;
let isProcessing = false;
let pollTimer: NodeJS.Timeout | null = null;
let sendMessage: ((message: string) => Promise<void>) | null = null;

export function setSendMessage(fn: (message: string) => Promise<void>) {
	sendMessage = fn;
}

/** Validate bearer token on incoming webhook request */
function validateToken(req: IncomingMessage): boolean {
	if (!WEBHOOK_TOKEN) return true; // No token configured = open (localhost only)
	const auth = req.headers["authorization"];
	if (!auth) return false;
	return auth === `Bearer ${WEBHOOK_TOKEN}`;
}

/** Format a Gitea event as a prompt for the LLM */
function formatEventPrompt(event: any): string {
	const action = event.action;
	const repo = event.repository?.full_name || "unknown";

	let prompt = `New Gitea event on ${repo}:\n\n`;
	prompt += `**Action**: ${action}\n\n`;

	if (event.issue) {
		const issue = event.issue;
		prompt += `**Issue #${issue.number}: ${issue.title}**\n`;
		prompt += `**Author**: @${issue.user?.login || "unknown"}\n`;
		prompt += `**Labels**: ${issue.labels?.map((l: any) => l.name).join(", ") || "none"}\n`;
		prompt += `**Body**:\n${issue.body || "(no body)"}\n\n`;
	}

	if (event.pull_request) {
		const pr = event.pull_request;
		prompt += `**PR #${pr.number}: ${pr.title}**\n`;
		prompt += `**Author**: @${pr.user?.login || "unknown"}\n`;
		prompt += `**Base**: ${pr.base?.label} ← **Head**: ${pr.head?.label}\n`;
		prompt += `**Body**:\n${pr.body || "(no body)"}\n\n`;
	}

	if (event.comment) {
		const comment = event.comment;
		const targetNumber = event.issue?.number || event.pull_request?.number;
		prompt += `**Comment on #${targetNumber}**\n`;
		prompt += `**Author**: @${comment.user?.login || "unknown"}\n`;
		prompt += `**Body**:\n${comment.body || "(no body)"}\n\n`;
	}

	if (event.pusher) {
		prompt += `**Pusher**: @${event.pusher.name}\n`;
		prompt += `**Commits**: ${event.commits?.length || 0}\n\n`;
	}

	prompt += `---\n\n`;
	prompt += `Please analyze this event and decide how to respond. You can:\n`;
	prompt += `1. Add helpful comments to issues/PRs\n`;
	prompt += `2. Suggest code fixes or improvements\n`;
	prompt += `3. Create branches and PRs to fix issues\n`;
	prompt += `4. Update files directly (if direct_push is enabled)\n`;
	prompt += `5. Ask for clarification if needed\n\n`;
	prompt += `Use the available Gitea tools to interact with the repository.`;

	return prompt;
}

/** Process the event queue */
async function processQueue() {
	if (isProcessing || processingQueue.length === 0) return;

	isProcessing = true;

	while (processingQueue.length > 0) {
		const { event } = processingQueue.shift()!;
		const repoName = event.repository?.full_name || "unknown";

		console.log(`[gitea-webhook] Processing event: ${event.action} on ${repoName}`);

		if (sendMessage) {
			try {
				const prompt = formatEventPrompt(event);
				await sendMessage(prompt);
				console.log(`[gitea-webhook] Event sent to LLM: ${event.action} on ${repoName}`);
			} catch (err) {
				console.error(`[gitea-webhook] Failed to send event to LLM:`, err);
			}
		} else {
			console.warn(`[gitea-webhook] No sendMessage function available, skipping event`);
		}
	}

	isProcessing = false;
}

/** Start webhook server */
export function startWebhookServer(_pi: ExtensionAPI) {
	return new Promise<void>(async (resolve, reject) => {
		try {
			const http = await import("node:http");

			server = http.createServer(async (req: IncomingMessage, res: ServerResponse) => {
				const url = req.url || "";

				res.setHeader("Access-Control-Allow-Origin", "*");
				res.setHeader("Access-Control-Allow-Methods", "GET, POST, OPTIONS");
				res.setHeader("Access-Control-Allow-Headers", "Content-Type, Authorization");

				if (req.method === "OPTIONS") {
					res.writeHead(200);
					res.end();
					return;
				}

				// GET /health
				if (url === "/health" && req.method === "GET") {
					res.writeHead(200, { "Content-Type": "application/json" });
					res.end(
						JSON.stringify({
							status: "ok",
							uptime: process.uptime(),
							tracked_repos: trackedRepos.size,
							queue_depth: processingQueue.length,
							is_processing: isProcessing,
						}),
					);
					return;
				}

				// POST /hooks/gitea
				if (url === "/hooks/gitea" && req.method === "POST") {
					// Validate token
					if (!validateToken(req)) {
						res.writeHead(401, { "Content-Type": "application/json" });
						res.end(JSON.stringify({ error: "Unauthorized" }));
						console.error("[gitea-webhook] Token validation failed");
						return;
					}

					// Read body
					let body = "";
					for await (const chunk of req) {
						body += chunk.toString();
					}

					// Parse event
					let event;
					try {
						event = JSON.parse(body);
					} catch {
						res.writeHead(400, { "Content-Type": "application/json" });
						res.end(JSON.stringify({ error: "Invalid JSON" }));
						return;
					}

					// Queue event
					processingQueue.push({ event, timestamp: Date.now() });

					if (processingQueue.length > maxQueueDepth) {
						const dropped = processingQueue.shift();
						if (dropped) {
							console.warn(`[gitea-webhook] Queue full, dropping oldest event`);
						}
					}

					void processQueue();

					res.writeHead(200, { "Content-Type": "application/json" });
					res.end(JSON.stringify({ received: true, event: event.action }));
					return;
				}

				res.writeHead(404, { "Content-Type": "text/plain" });
				res.end("Not found");
			});

			server.listen(WEBHOOK_PORT, WEBHOOK_HOST, () => {
				console.log(`[gitea-webhook] Server listening on ${WEBHOOK_HOST}:${WEBHOOK_PORT}`);
				resolve();
			});

			server.on("error", reject);
		} catch (err) {
			reject(err);
		}
	});
}

/** Stop webhook server */
export async function stopWebhookServer() {
	return new Promise<void>((resolve) => {
		if (server) {
			server.close(() => {
				console.log("[gitea-webhook] Server stopped");
				server = null;
				resolve();
			});
		} else {
			resolve();
		}
	});
}

/** Poll for new repos and register webhooks */
export function startPolling(_pi: ExtensionAPI) {
	void fetchUserRepos();
	pollTimer = setInterval(() => void fetchUserRepos(), POLL_INTERVAL * 1000);
	console.log(`[gitea-polling] Polling started (interval: ${POLL_INTERVAL}s)`);
}

export function stopPolling() {
	if (pollTimer) {
		clearInterval(pollTimer);
		pollTimer = null;
	}
}

async function fetchUserRepos() {
	try {
		const client = new GiteaClient();
		if (!WEBHOOK_URL) {
			console.warn("[gitea-polling] PI_WEBHOOK_URL not set, skipping webhook registration");
			return;
		}

		const repos = await client.get<any[]>("/user/repos?limit=100");

		const newRepos: any[] = [];
		for (const repo of repos) {
			if (!trackedRepos.has(repo.full_name)) {
				newRepos.push(repo);
			}
		}

		if (newRepos.length > 0) {
			console.log(`[gitea-polling] Found ${newRepos.length} new repos, registering webhooks...`);

			for (const repo of newRepos) {
				try {
					const webhook = await client.post<any>(`/repos/${repo.full_name}/hooks`, {
						type: "gitea",
						config: {
							url: `${WEBHOOK_URL}/hooks/gitea`,
							content_type: "json",
							...(WEBHOOK_TOKEN ? { authorization: `Bearer ${WEBHOOK_TOKEN}` } : {}),
						},
						events: ["issues", "issue_comment", "pull_request", "push"],
						active: true,
					});

					trackedRepos.set(repo.full_name, { webhookId: webhook.id, addedAt: Date.now() });
					console.log(`[gitea-polling] Webhook created for ${repo.full_name} (ID: ${webhook.id})`);
				} catch (err) {
					console.error(`[gitea-polling] Error creating webhook for ${repo.full_name}:`, err);
				}
			}
		}

		console.log(`[gitea-polling] Current repos: ${trackedRepos.size}`);
	} catch (err) {
		console.error("[gitea-polling] Error fetching user repos:", err);
	}
}

export function getTrackedRepos() {
	return new Map(trackedRepos);
}