import { tryParseJson } from "@oh-my-pi/pi-utils";
import type { RenderResult, SpecialHandler } from "./types";
import { buildResult, formatNumber, loadPage } from "./types";

interface OpenVsxFileLinks {
	readme?: string;
}

interface OpenVsxExtension {
	name: string;
	namespace: string;
	version: string;
	displayName?: string;
	description?: string;
	downloadCount?: number;
	averageRating?: number;
	reviewCount?: number;
	repository?: string | { url?: string };
	license?: string;
	categories?: string[];
	homepage?: string;
	files?: OpenVsxFileLinks;
}

/**
 * Handle Open VSX URLs via their API
 */
export const handleOpenVsx: SpecialHandler = async (
	url: string,
	timeout: number,
	signal?: AbortSignal,
): Promise<RenderResult | null> => {
	try {
		const parsed = new URL(url);
		if (parsed.hostname !== "open-vsx.org" && parsed.hostname !== "www.open-vsx.org") return null;

		const match = parsed.pathname.match(/^\/extension\/([^/]+)\/([^/]+)(?:\/([^/]+))?\/?$/);
		if (!match) return null;

		const namespace = decodeURIComponent(match[1]);
		const extension = decodeURIComponent(match[2]);
		const version = match[3] ? decodeURIComponent(match[3]) : null;

		const fetchedAt = new Date().toISOString();
		const baseUrl = `https://open-vsx.org/api/${encodeURIComponent(namespace)}/${encodeURIComponent(extension)}`;
		const apiUrl = version ? `${baseUrl}/${encodeURIComponent(version)}` : baseUrl;

		const result = await loadPage(apiUrl, { timeout, signal });
		if (!result.ok) return null;

		const data = tryParseJson<OpenVsxExtension>(result.content);
		if (!data) return null;

		let readme: string | null = null;
		const readmeUrl = data.files?.readme;
		if (readmeUrl) {
			try {
				const readmeResult = await loadPage(readmeUrl, { timeout: Math.min(timeout, 10), signal });
				if (readmeResult.ok) readme = readmeResult.content;
			} catch {}
		}

		const displayName = data.displayName || data.name || `${namespace}/${extension}`;
		const displayNamespace = data.namespace || namespace;
		const displayVersion = data.version || version || "unknown";
		const downloads = typeof data.downloadCount === "number" ? data.downloadCount : null;
		const rating = typeof data.averageRating === "number" ? data.averageRating : null;
		const reviews = typeof data.reviewCount === "number" ? data.reviewCount : null;
		const repository = typeof data.repository === "string" ? data.repository : data.repository?.url || null;

		let md = `# ${displayName}\n\n`;
		if (data.description) md += `${data.description}\n\n`;

		md += `**Namespace:** ${displayNamespace}\n`;
		md += `**Extension:** ${data.name || extension}\n`;
		md += `**Version:** ${displayVersion}`;
		if (data.license) md += ` | **License:** ${data.license}`;
		md += "\n";

		if (downloads !== null) {
			md += `**Downloads:** ${formatNumber(downloads)}\n`;
		}

		if (rating !== null) {
			const reviewSuffix = reviews !== null ? ` (${reviews} reviews)` : "";
			md += `**Rating:** ${rating}${reviewSuffix}\n`;
		}

		if (repository) {
			const cleanedRepo = repository.replace(/^git\+/, "").replace(/\.git$/, "");
			md += `**Repository:** ${cleanedRepo}\n`;
		}

		if (data.homepage) md += `**Homepage:** ${data.homepage}\n`;
		if (data.categories?.length) md += `**Categories:** ${data.categories.join(", ")}\n`;

		if (readme) {
			md += "\n---\n\n## README\n\n";
			md += `${readme}\n`;
		}

		return buildResult(md, { url, method: "open-vsx", fetchedAt, notes: ["Fetched via Open VSX API"] });
	} catch {}

	return null;
};