import { spawn } from "node:child_process";
import crypto from "node:crypto";
import { createServer } from "node:http";
import path from "node:path";
import { promises as fs } from "node:fs";
import process from "node:process";
import matter from "gray-matter";

const ROOT_DIR = process.cwd();
const DIST_DIR = path.join(ROOT_DIR, "dist");
const STORAGE_ADMIN_DIR = path.join(ROOT_DIR, "storage", "admin");
const CONFIG_JSON_PATH = path.join(STORAGE_ADMIN_DIR, "config.json");
const POSTS_DIR = path.join(ROOT_DIR, "src", "content", "posts");
const SPEC_DIR = path.join(ROOT_DIR, "src", "content", "spec");
const PUBLIC_DIR = path.join(ROOT_DIR, "public");
const PUBLIC_ADMIN_ASSETS_DIR = PUBLIC_DIR;
const PUBLIC_MEDIA_ROUTE = "/admin-assets/";
const CONTENT_MEDIA_ROUTE = "/__content-media/";
const SAKURA_OVERRIDE_PATH = path.join(
	ROOT_DIR,
	"src",
	"admin",
	"overrides",
	"sakuraConfig.override.json",
);
const FOOTER_HTML_PATH = path.join(ROOT_DIR, "src", "config", "FooterConfig.html");
const BUILD_LOG_LIMIT = 400;
const SESSION_COOKIE = "firefly_admin_session";
const SESSION_TTL_MS = 1000 * 60 * 60 * 24;
const MAX_JSON_BODY_BYTES = 1024 * 1024 * 40;
const PORT = Number.parseInt(process.env.PORT || "7860", 10);

const MIME_TYPES = {
	".avif": "image/avif",
	".css": "text/css; charset=utf-8",
	".gif": "image/gif",
	".html": "text/html; charset=utf-8",
	".ico": "image/x-icon",
	".jpeg": "image/jpeg",
	".jpg": "image/jpeg",
	".js": "text/javascript; charset=utf-8",
	".json": "application/json; charset=utf-8",
	".map": "application/json; charset=utf-8",
	".md": "text/markdown; charset=utf-8",
	".mp3": "audio/mpeg",
	".png": "image/png",
	".svg": "image/svg+xml",
	".txt": "text/plain; charset=utf-8",
	".wav": "audio/wav",
	".webp": "image/webp",
	".woff": "font/woff",
	".woff2": "font/woff2",
	".xml": "application/xml; charset=utf-8",
};

const IMAGE_EXTENSIONS = new Set([
	".png",
	".jpg",
	".jpeg",
	".webp",
	".gif",
	".svg",
	".avif",
]);

const MARKDOWN_EXTENSIONS = new Set([".md", ".mdx"]);

const SECTION_ALIASES = {
	background: "wallpaper",
	ads: "ad",
	cover: "coverImage",
};

const sessions = new Map();

const buildState = {
	status: "idle",
	startedAt: null,
	finishedAt: null,
	lastBuiltAt: null,
	lastDurationMs: null,
	lastError: "",
	logs: [],
	queueLength: 0,
	queuedReason: "",
};

let activeBuildProcess = null;

function nowIso() {
	return new Date().toISOString();
}

function buildCommand() {
	return process.platform === "win32" ? "pnpm.cmd" : "pnpm";
}

function normalizeSlashes(value) {
	return value.replace(/\\/g, "/");
}

function sanitizeSegment(value) {
	return String(value)
		.trim()
		.replace(/[<>:"|?*\x00-\x1f]/g, "-")
		.replace(/\.+/g, ".")
		.replace(/^\.+/, "")
		.replace(/[\\/]+/g, "-");
}

function ensureInside(baseDir, targetPath) {
	const resolvedBase = path.resolve(baseDir);
	const resolvedTarget = path.resolve(targetPath);
	if (
		resolvedTarget !== resolvedBase &&
		!resolvedTarget.startsWith(`${resolvedBase}${path.sep}`)
	) {
		throw new Error("Invalid path");
	}
	return resolvedTarget;
}

function normalizeSectionKey(section) {
	const raw = String(section || "").trim();
	return SECTION_ALIASES[raw] || raw;
}

function respond(res, statusCode, body, headers = {}) {
	res.writeHead(statusCode, headers);
	res.end(body);
}

function respondJson(res, statusCode, data, headers = {}) {
	respond(
		res,
		statusCode,
		JSON.stringify(data),
		{
			"Cache-Control": "no-store",
			"Content-Type": "application/json; charset=utf-8",
			...headers,
		},
	);
}

function respondError(res, statusCode, message, details = undefined) {
	respondJson(res, statusCode, {
		error: message,
		...(details === undefined ? {} : { details }),
	});
}

function redirect(res, location, statusCode = 302) {
	respond(res, statusCode, "", {
		"Cache-Control": "no-store",
		Location: location,
	});
}

function parseCookies(req) {
	const header = req.headers.cookie || "";
	return header
		.split(";")
		.map((item) => item.trim())
		.filter(Boolean)
		.reduce((acc, item) => {
			const separatorIndex = item.indexOf("=");
			if (separatorIndex < 0) {
				return acc;
			}
			const key = item.slice(0, separatorIndex);
			const value = item.slice(separatorIndex + 1);
			acc[key] = decodeURIComponent(value);
			return acc;
		}, {});
}

function setCookie(res, name, value, options = {}) {
	const parts = [`${name}=${encodeURIComponent(value)}`];
	parts.push(`Path=${options.path || "/"}`);
	if (options.httpOnly !== false) {
		parts.push("HttpOnly");
	}
	parts.push(`SameSite=${options.sameSite || "Lax"}`);
	if (options.maxAge !== undefined) {
		parts.push(`Max-Age=${options.maxAge}`);
	}
	const existing = res.getHeader("Set-Cookie");
	const nextValue = Array.isArray(existing)
		? [...existing, parts.join("; ")]
		: existing
			? [existing, parts.join("; ")]
			: parts.join("; ");
	res.setHeader("Set-Cookie", nextValue);
}

function clearCookie(res, name) {
	setCookie(res, name, "", { maxAge: 0 });
}

async function readRequestBody(req, maxBytes = MAX_JSON_BODY_BYTES) {
	return await new Promise((resolve, reject) => {
		let totalBytes = 0;
		const chunks = [];

		req.on("data", (chunk) => {
			totalBytes += chunk.length;
			if (totalBytes > maxBytes) {
				reject(new Error("Request body too large"));
				req.destroy();
				return;
			}
			chunks.push(chunk);
		});

		req.on("end", () => {
			resolve(Buffer.concat(chunks).toString("utf8"));
		});
		req.on("error", reject);
	});
}

async function readJsonBody(req) {
	const raw = await readRequestBody(req);
	return raw ? JSON.parse(raw) : {};
}

async function readFormBody(req) {
	const raw = await readRequestBody(req);
	const params = new URLSearchParams(raw);
	return Object.fromEntries(params.entries());
}

async function statSafe(filePath) {
	try {
		return await fs.stat(filePath);
	} catch {
		return null;
	}
}

async function ensureRuntimeFiles() {
	await fs.mkdir(STORAGE_ADMIN_DIR, { recursive: true });
	await fs.mkdir(PUBLIC_ADMIN_ASSETS_DIR, { recursive: true });
	await fs.mkdir(path.dirname(SAKURA_OVERRIDE_PATH), { recursive: true });
	await fs.mkdir(path.dirname(FOOTER_HTML_PATH), { recursive: true });

	if (!(await statSafe(CONFIG_JSON_PATH))) {
		await fs.writeFile(CONFIG_JSON_PATH, "{}\n", "utf8");
	}
	if (!(await statSafe(SAKURA_OVERRIDE_PATH))) {
		await fs.writeFile(SAKURA_OVERRIDE_PATH, "{}\n", "utf8");
	}
	if (!(await statSafe(FOOTER_HTML_PATH))) {
		await fs.writeFile(FOOTER_HTML_PATH, "", "utf8");
	}
}

async function readJsonFile(filePath, fallback = {}) {
	try {
		const raw = await fs.readFile(filePath, "utf8");
		return raw.trim() ? JSON.parse(raw) : fallback;
	} catch {
		return fallback;
	}
}

async function readAdminConfig() {
	const config = await readJsonFile(CONFIG_JSON_PATH, {});
	return typeof config === "object" && config !== null && !Array.isArray(config)
		? config
		: {};
}

async function writeAdminConfig(config) {
	await fs.writeFile(CONFIG_JSON_PATH, `${JSON.stringify(config, null, 2)}\n`, "utf8");
}

async function readSakuraConfig() {
	const sakura = await readJsonFile(SAKURA_OVERRIDE_PATH, {});
	return typeof sakura === "object" && sakura !== null && !Array.isArray(sakura)
		? sakura
		: {};
}

async function writeSakuraConfig(config) {
	await fs.writeFile(SAKURA_OVERRIDE_PATH, `${JSON.stringify(config, null, 2)}\n`, "utf8");
}

async function syncFooterHtmlFromConfig(config) {
	const html = String(config?.footer?.customHtml || "");
	await fs.writeFile(FOOTER_HTML_PATH, html, "utf8");
}

async function getEffectiveConfig() {
	const config = await readAdminConfig();
	const sakura = await readSakuraConfig();
	return {
		site: config.site || {},
		navbar: config.navbar || { links: [] },
		sidebar: config.sidebar || {},
		profile: config.profile || {},
		wallpaper: config.wallpaper || {},
		announcement: config.announcement || {},
		footer: config.footer || {},
		comment: config.comment || {},
		friends: config.friends || { page: { columns: 2 }, items: [] },
		sponsor: config.sponsor || {},
		music: config.music || {},
		pio: config.pio || {},
		ad: config.ad || {},
		license: config.license || {},
		coverImage: config.coverImage || {},
		font: config.site?.font || {},
		sakura,
	};
}

async function writeConfigSection(section, data) {
	if (typeof data !== "object" || data === null || Array.isArray(data)) {
		throw new Error("Config payload must be an object");
	}

	const normalizedSection = normalizeSectionKey(section);
	if (normalizedSection === "sakura") {
		await writeSakuraConfig(data);
		return;
	}

	const config = await readAdminConfig();
	if (normalizedSection === "font") {
		config.site = typeof config.site === "object" && config.site !== null ? config.site : {};
		config.site.font = data;
	} else {
		config[normalizedSection] = data;
	}

	await writeAdminConfig(config);
	if (normalizedSection === "footer") {
		await syncFooterHtmlFromConfig(config);
	}
}

function serializeBuildState() {
	return {
		status: buildState.status,
		startedAt: buildState.startedAt,
		finishedAt: buildState.finishedAt,
		lastBuiltAt: buildState.lastBuiltAt,
		lastDurationMs: buildState.lastDurationMs,
		lastError: buildState.lastError,
		queueLength: buildState.queueLength,
		queuedReason: buildState.queuedReason,
		logs: [...buildState.logs],
	};
}

function appendBuildLog(message) {
	const text = String(message || "").trim();
	if (!text) {
		return;
	}
	buildState.logs.push(`${new Date().toLocaleTimeString()} ${text}`);
	if (buildState.logs.length > BUILD_LOG_LIMIT) {
		buildState.logs = buildState.logs.slice(-BUILD_LOG_LIMIT);
	}
}

function startBuild(reason = "manual") {
	buildState.status = "building";
	buildState.startedAt = nowIso();
	buildState.finishedAt = null;
	buildState.lastDurationMs = null;
	buildState.lastError = "";
	buildState.logs = [];
	appendBuildLog(`Build started (${reason})`);

	const startedAtMs = Date.now();
	const child = spawn(buildCommand(), ["build"], {
		cwd: ROOT_DIR,
		env: process.env,
		stdio: ["ignore", "pipe", "pipe"],
	});
	activeBuildProcess = child;

	child.stdout.on("data", (chunk) => {
		appendBuildLog(String(chunk).trimEnd());
	});
	child.stderr.on("data", (chunk) => {
		appendBuildLog(String(chunk).trimEnd());
	});
	child.on("error", (error) => {
		buildState.status = "error";
		buildState.finishedAt = nowIso();
		buildState.lastDurationMs = Date.now() - startedAtMs;
		buildState.lastError = error.message;
		appendBuildLog(`Build failed: ${error.message}`);
		activeBuildProcess = null;
		flushBuildQueue();
	});
	child.on("close", (code) => {
		buildState.finishedAt = nowIso();
		buildState.lastDurationMs = Date.now() - startedAtMs;
		if (code === 0) {
			buildState.status = "success";
			buildState.lastBuiltAt = nowIso();
			appendBuildLog("Build completed successfully");
		} else {
			buildState.status = "error";
			buildState.lastError = `Build exited with code ${code}`;
			appendBuildLog(buildState.lastError);
		}
		activeBuildProcess = null;
		flushBuildQueue();
	});
}

function flushBuildQueue() {
	if (activeBuildProcess || buildState.queueLength < 1) {
		return;
	}
	const nextReason = buildState.queuedReason || "queued";
	buildState.queueLength = 0;
	buildState.queuedReason = "";
	startBuild(nextReason);
}

function scheduleBuild(reason = "manual") {
	if (activeBuildProcess) {
		buildState.queueLength = 1;
		buildState.queuedReason = reason;
		appendBuildLog(`Build queued (${reason})`);
		return { started: false, queued: true };
	}
	startBuild(reason);
	return { started: true, queued: false };
}

function createSession(username) {
	const token = crypto.randomBytes(24).toString("hex");
	sessions.set(token, {
		username,
		expiresAt: Date.now() + SESSION_TTL_MS,
	});
	return token;
}

function getSession(req) {
	const cookies = parseCookies(req);
	const token = cookies[SESSION_COOKIE];
	if (!token) {
		return null;
	}
	const session = sessions.get(token);
	if (!session) {
		return null;
	}
	if (session.expiresAt < Date.now()) {
		sessions.delete(token);
		return null;
	}
	return { token, ...session };
}

function requireAuth(req, res) {
	const session = getSession(req);
	if (!session) {
		respondError(res, 401, "Authentication required");
		return null;
	}
	return session;
}

function isAdminConfigured() {
	return Boolean(process.env.ADMIN && process.env.PASSWORD);
}

function completeAdminLogin(res, username) {
	const token = createSession(String(username));
	setCookie(res, SESSION_COOKIE, token, {
		maxAge: Math.floor(SESSION_TTL_MS / 1000),
	});
	return token;
}

function getAdminEntryPath(pathname = "/admin/login") {
	return pathname.startsWith("/cmsadmin") ? "/cmsadmin/" : "/admin/";
}

async function handleAdminFormLogin(req, res, url) {
	const entryPath = getAdminEntryPath(url.pathname);
	if (!isAdminConfigured()) {
		return redirect(res, entryPath + "?login=disabled");
	}
	const contentType = String(req.headers["content-type"] || "");
	const payload = contentType.includes("application/json")
		? await readJsonBody(req)
		: await readFormBody(req);
	const username = String(payload.username || "");
	const password = String(payload.password || "");
	if (username !== process.env.ADMIN || password !== process.env.PASSWORD) {
		return redirect(res, entryPath + "?login=invalid");
	}
	completeAdminLogin(res, username);
	return redirect(res, entryPath);
}

async function walkFiles(dirPath) {
	const stats = await statSafe(dirPath);
	if (!stats?.isDirectory()) {
		return [];
	}

	const items = await fs.readdir(dirPath, { withFileTypes: true });
	const results = [];
	for (const item of items) {
		const absolutePath = path.join(dirPath, item.name);
		if (item.isDirectory()) {
			results.push(...(await walkFiles(absolutePath)));
			continue;
		}
		results.push(absolutePath);
	}
	return results;
}

function normalizeTags(tags) {
	if (Array.isArray(tags)) {
		return tags.map((item) => String(item).trim()).filter(Boolean);
	}
	if (typeof tags === "string") {
		return tags
			.split(",")
			.map((item) => item.trim())
			.filter(Boolean);
	}
	return [];
}

function postFileToSlug(filePath) {
	return normalizeSlashes(path.relative(POSTS_DIR, filePath)).replace(/\.(md|mdx)$/i, "");
}

function pageFileToSlug(filePath) {
	return normalizeSlashes(path.relative(SPEC_DIR, filePath)).replace(/\.(md|mdx)$/i, "");
}

function normalizePostFrontmatter(payload) {
	return {
		title: String(payload.title || "Untitled"),
		published: String(payload.published || new Date().toISOString().slice(0, 10)),
		...(payload.updated ? { updated: String(payload.updated) } : {}),
		description: String(payload.description || ""),
		image: String(payload.image || ""),
		tags: normalizeTags(payload.tags),
		category: String(payload.category || ""),
		draft: Boolean(payload.draft),
		lang: String(payload.lang || ""),
		pinned: Boolean(payload.pinned),
		author: String(payload.author || ""),
		sourceLink: String(payload.sourceLink || ""),
		licenseName: String(payload.licenseName || ""),
		licenseUrl: String(payload.licenseUrl || ""),
		comment: payload.comment !== false,
	};
}

async function listPosts() {
	const files = await walkFiles(POSTS_DIR);
	const markdownFiles = files.filter((filePath) =>
		MARKDOWN_EXTENSIONS.has(path.extname(filePath).toLowerCase()),
	);

	const posts = await Promise.all(
		markdownFiles.map(async (filePath) => {
			const raw = await fs.readFile(filePath, "utf8");
			const parsed = matter(raw);
			const data = parsed.data || {};
			return {
				slug: postFileToSlug(filePath),
				filePath: normalizeSlashes(path.relative(ROOT_DIR, filePath)),
				title: String(data.title || postFileToSlug(filePath)),
				published: String(data.published || ""),
				updated: String(data.updated || ""),
				description: String(data.description || ""),
				image: String(data.image || ""),
				tags: normalizeTags(data.tags),
				category: String(data.category || ""),
				draft: Boolean(data.draft),
				pinned: Boolean(data.pinned),
				lang: String(data.lang || ""),
				comment: data.comment !== false,
				author: String(data.author || ""),
				sourceLink: String(data.sourceLink || ""),
				licenseName: String(data.licenseName || ""),
				licenseUrl: String(data.licenseUrl || ""),
				excerpt: parsed.content.trim().slice(0, 200),
				modifiedAt: (await fs.stat(filePath)).mtime.toISOString(),
			};
		}),
	);

	return posts.sort((left, right) => {
		const pinnedDiff = Number(right.pinned) - Number(left.pinned);
		if (pinnedDiff !== 0) {
			return pinnedDiff;
		}
		return `${right.published}`.localeCompare(`${left.published}`);
	});
}

async function resolvePostFile(slug) {
	const safeSlug = normalizeSlashes(String(slug || "")).replace(/^\/+|\/+$/g, "");
	for (const extension of ["md", "mdx"]) {
		const filePath = ensureInside(POSTS_DIR, path.join(POSTS_DIR, `${safeSlug}.${extension}`));
		if (await statSafe(filePath)) {
			return filePath;
		}
	}
	return null;
}

async function readPost(slug) {
	const filePath = await resolvePostFile(slug);
	if (!filePath) {
		return null;
	}
	const raw = await fs.readFile(filePath, "utf8");
	const parsed = matter(raw);
	const data = normalizePostFrontmatter(parsed.data || {});
	return {
		slug: postFileToSlug(filePath),
		filePath: normalizeSlashes(path.relative(ROOT_DIR, filePath)),
		extension: path.extname(filePath).slice(1),
		...data,
		body: parsed.content,
	};
}

async function writePost(existingSlug, payload) {
	const nextSlug = normalizeSlashes(String(payload.slug || existingSlug || "untitled"))
		.replace(/^\/+|\/+$/g, "")
		.split("/")
		.map(sanitizeSegment)
		.filter(Boolean)
		.join("/");

	if (!nextSlug) {
		throw new Error("Post slug cannot be empty");
	}

	const previousPath = existingSlug ? await resolvePostFile(existingSlug) : null;
	const extension =
		payload.extension === "mdx" || path.extname(previousPath || "") === ".mdx"
			? "mdx"
			: "md";
	const nextPath = ensureInside(POSTS_DIR, path.join(POSTS_DIR, `${nextSlug}.${extension}`));
	await fs.mkdir(path.dirname(nextPath), { recursive: true });

	if (!previousPath && (await statSafe(nextPath))) {
		throw new Error("Another post already uses this slug");
	}
	if (previousPath && previousPath !== nextPath && (await statSafe(nextPath))) {
		throw new Error("Another post already uses this slug");
	}
	if (previousPath && previousPath !== nextPath) {
		await fs.rename(previousPath, nextPath);
	}

	const frontmatter = normalizePostFrontmatter(payload);
	const body = String(payload.body ?? payload.content ?? "");
	const output = matter.stringify(body, frontmatter);
	await fs.writeFile(nextPath, output, "utf8");
	return await readPost(nextSlug);
}

async function deletePost(slug) {
	const filePath = await resolvePostFile(slug);
	if (!filePath) {
		return false;
	}
	await fs.unlink(filePath);
	return true;
}

async function listPages() {
	const files = await walkFiles(SPEC_DIR);
	const markdownFiles = files.filter((filePath) =>
		MARKDOWN_EXTENSIONS.has(path.extname(filePath).toLowerCase()),
	);
	const pages = await Promise.all(
		markdownFiles.map(async (filePath) => ({
			slug: pageFileToSlug(filePath),
			filePath: normalizeSlashes(path.relative(ROOT_DIR, filePath)),
			body: await fs.readFile(filePath, "utf8"),
			modifiedAt: (await fs.stat(filePath)).mtime.toISOString(),
		})),
	);
	return pages.sort((left, right) => left.slug.localeCompare(right.slug));
}

async function readPage(slug) {
	const safeSlug = normalizeSlashes(String(slug || "")).replace(/^\/+|\/+$/g, "");
	for (const extension of ["md", "mdx"]) {
		const filePath = ensureInside(SPEC_DIR, path.join(SPEC_DIR, `${safeSlug}.${extension}`));
		if (await statSafe(filePath)) {
			return {
				slug: pageFileToSlug(filePath),
				filePath: normalizeSlashes(path.relative(ROOT_DIR, filePath)),
				extension,
				body: await fs.readFile(filePath, "utf8"),
			};
		}
	}
	return null;
}

async function writePage(slug, body) {
	const safeSlug = normalizeSlashes(String(slug || ""))
		.replace(/^\/+|\/+$/g, "")
		.split("/")
		.map(sanitizeSegment)
		.filter(Boolean)
		.join("/");

	if (!safeSlug) {
		throw new Error("Page slug cannot be empty");
	}

	const existing = await readPage(safeSlug);
	const extension = existing?.extension || "md";
	const filePath = ensureInside(SPEC_DIR, path.join(SPEC_DIR, `${safeSlug}.${extension}`));
	await fs.mkdir(path.dirname(filePath), { recursive: true });
	await fs.writeFile(filePath, String(body || ""), "utf8");
	return await readPage(safeSlug);
}

async function buildAssetRecord(rootKey, baseDir, filePath) {
	const stat = await fs.stat(filePath);
	const relativePath = normalizeSlashes(path.relative(baseDir, filePath));
	const directory = normalizeSlashes(path.dirname(relativePath));
	const previewUrl =
		rootKey === "public"
			? `${PUBLIC_MEDIA_ROUTE}${relativePath}`
			: `${CONTENT_MEDIA_ROUTE}${relativePath}`;
	const reference = rootKey === "public" ? `/${relativePath}` : relativePath;

	return {
		root: rootKey,
		path: relativePath,
		name: path.basename(filePath),
		directory: directory === "." ? "" : directory,
		size: stat.size,
		modifiedAt: stat.mtime.toISOString(),
		previewUrl,
		reference,
	};
}

async function listAssets() {
	const roots = [
		{ key: "public", dir: PUBLIC_ADMIN_ASSETS_DIR },
		{ key: "content", dir: POSTS_DIR },
	];
	const assetGroups = await Promise.all(
		roots.map(async ({ key, dir }) => {
			const files = await walkFiles(dir);
			const imageFiles = files.filter((filePath) =>
				IMAGE_EXTENSIONS.has(path.extname(filePath).toLowerCase()),
			);
			return await Promise.all(
				imageFiles.map((filePath) => buildAssetRecord(key, dir, filePath)),
			);
		}),
	);

	return assetGroups.flat().sort((left, right) => right.modifiedAt.localeCompare(left.modifiedAt));
}

function parseDataUrl(dataUrl) {
	const match = /^data:([^;]+);base64,(.+)$/u.exec(String(dataUrl || ""));
	if (!match) {
		throw new Error("Invalid data URL");
	}
	return {
		mimeType: match[1],
		buffer: Buffer.from(match[2], "base64"),
	};
}

async function writeAsset(payload) {
	const root = payload.root === "content" ? "content" : "public";
	const folderSegments = String(payload.folder || "")
		.split("/")
		.map(sanitizeSegment)
		.filter(Boolean);
	const fileName = sanitizeSegment(payload.name || `asset-${Date.now()}`);
	if (!fileName) {
		throw new Error("Asset name cannot be empty");
	}

	const { buffer } = parseDataUrl(payload.dataUrl);
	const baseDir = root === "content" ? POSTS_DIR : PUBLIC_ADMIN_ASSETS_DIR;
	const effectiveFolders =
		root === "content" && folderSegments.length === 0 ? ["images"] : folderSegments;
	const targetDir = ensureInside(baseDir, path.join(baseDir, ...effectiveFolders));
	await fs.mkdir(targetDir, { recursive: true });

	let candidateName = fileName;
	let candidatePath = ensureInside(targetDir, path.join(targetDir, candidateName));
	let counter = 1;
	while (await statSafe(candidatePath)) {
		const extension = path.extname(fileName);
		const baseName = path.basename(fileName, extension);
		candidateName = `${baseName}-${counter}${extension}`;
		candidatePath = ensureInside(targetDir, path.join(targetDir, candidateName));
		counter += 1;
	}

	await fs.writeFile(candidatePath, buffer);
	return await buildAssetRecord(root, baseDir, candidatePath);
}

async function deleteAsset(root, relativePath) {
	const baseDir = root === "content" ? POSTS_DIR : PUBLIC_ADMIN_ASSETS_DIR;
	const safeRelativePath = normalizeSlashes(String(relativePath || ""))
		.split("/")
		.map(sanitizeSegment)
		.filter(Boolean)
		.join(path.sep);
	if (!safeRelativePath) {
		throw new Error("Asset path cannot be empty");
	}
	const absolutePath = ensureInside(baseDir, path.join(baseDir, safeRelativePath));
	await fs.unlink(absolutePath);
}

async function collectStats() {
	const [posts, pages, assets] = await Promise.all([listPosts(), listPages(), listAssets()]);
	const tags = new Set();
	const categories = new Set();
	for (const post of posts) {
		for (const tag of post.tags) {
			tags.add(tag);
		}
		if (post.category) {
			categories.add(post.category);
		}
	}

	return {
		posts: posts.length,
		drafts: posts.filter((post) => post.draft).length,
		pages: pages.length,
		assets: assets.length,
		tags: tags.size,
		categories: categories.size,
		build: serializeBuildState(),
	};
}

async function handleApiRequest(req, res, url) {
	const pathname = url.pathname;

	if (pathname === "/api/admin/session" && req.method === "GET") {
		const session = getSession(req);
		return respondJson(res, 200, {
			authenticated: Boolean(session),
			configured: isAdminConfigured(),
			username: session?.username || "",
			build: serializeBuildState(),
		});
	}

	if (pathname === "/api/admin/login" && req.method === "POST") {
		if (!isAdminConfigured()) {
			return respondError(
				res,
				500,
				"ADMIN and PASSWORD must be configured in environment variables",
			);
		}
		const payload = await readJsonBody(req);
		if (payload.username !== process.env.ADMIN || payload.password !== process.env.PASSWORD) {
			return respondError(res, 401, "Invalid username or password");
		}
		completeAdminLogin(res, payload.username);
		return respondJson(res, 200, {
			success: true,
			authenticated: true,
			username: payload.username,
			build: serializeBuildState(),
		});
	}

	if (pathname === "/api/admin/logout" && req.method === "POST") {
		const session = getSession(req);
		if (session) {
			sessions.delete(session.token);
		}
		clearCookie(res, SESSION_COOKIE);
		return respondJson(res, 200, { success: true });
	}

	const session = requireAuth(req, res);
	if (!session) {
		return;
	}

	if (pathname === "/api/admin/config" && req.method === "GET") {
		return respondJson(res, 200, {
			config: await getEffectiveConfig(),
		});
	}

	if (pathname.startsWith("/api/admin/config/") && req.method === "PUT") {
		const section = pathname.slice("/api/admin/config/".length);
		const payload = await readJsonBody(req);
		await writeConfigSection(section, payload);
		const buildAction = scheduleBuild(`config:${normalizeSectionKey(section)}`);
		return respondJson(res, 200, {
			success: true,
			section: normalizeSectionKey(section),
			...buildAction,
			build: serializeBuildState(),
		});
	}

	if (pathname === "/api/admin/dashboard" && req.method === "GET") {
		return respondJson(res, 200, await collectStats());
	}

	if (pathname === "/api/admin/build" && req.method === "GET") {
		return respondJson(res, 200, serializeBuildState());
	}

	if (pathname === "/api/admin/rebuild" && req.method === "POST") {
		const buildAction = scheduleBuild("manual");
		return respondJson(res, 200, {
			...buildAction,
			build: serializeBuildState(),
		});
	}

	if (pathname === "/api/admin/pages" && req.method === "GET") {
		return respondJson(res, 200, {
			pages: await listPages(),
		});
	}

	if (pathname.startsWith("/api/admin/pages/") && req.method === "GET") {
		const slug = decodeURIComponent(pathname.slice("/api/admin/pages/".length));
		const page = await readPage(slug);
		if (!page) {
			return respondError(res, 404, "Page not found");
		}
		return respondJson(res, 200, page);
	}

	if (pathname.startsWith("/api/admin/pages/") && req.method === "PUT") {
		const slug = decodeURIComponent(pathname.slice("/api/admin/pages/".length));
		const payload = await readJsonBody(req);
		const page = await writePage(slug, payload.body ?? payload.content ?? "");
		const buildAction =
			payload.publish === true
				? scheduleBuild(`page:${slug}`)
				: { started: false, queued: false };
		return respondJson(res, 200, {
			success: true,
			page,
			...buildAction,
			build: serializeBuildState(),
		});
	}

	if (pathname === "/api/admin/posts" && req.method === "GET") {
		return respondJson(res, 200, {
			posts: await listPosts(),
		});
	}

	if (pathname === "/api/admin/posts" && req.method === "POST") {
		const payload = await readJsonBody(req);
		const post = await writePost(null, payload);
		const buildAction =
			payload.publish === true
				? scheduleBuild(`post:${post.slug}`)
				: { started: false, queued: false };
		return respondJson(res, 200, {
			success: true,
			post,
			...buildAction,
			build: serializeBuildState(),
		});
	}

	if (pathname.startsWith("/api/admin/posts/") && req.method === "GET") {
		const slug = decodeURIComponent(pathname.slice("/api/admin/posts/".length));
		const post = await readPost(slug);
		if (!post) {
			return respondError(res, 404, "Post not found");
		}
		return respondJson(res, 200, post);
	}

	if (pathname.startsWith("/api/admin/posts/") && req.method === "PUT") {
		const slug = decodeURIComponent(pathname.slice("/api/admin/posts/".length));
		const payload = await readJsonBody(req);
		const post = await writePost(slug, payload);
		const buildAction =
			payload.publish === true
				? scheduleBuild(`post:${post.slug}`)
				: { started: false, queued: false };
		return respondJson(res, 200, {
			success: true,
			post,
			...buildAction,
			build: serializeBuildState(),
		});
	}

	if (pathname.startsWith("/api/admin/posts/") && req.method === "DELETE") {
		const slug = decodeURIComponent(pathname.slice("/api/admin/posts/".length));
		const deleted = await deletePost(slug);
		if (!deleted) {
			return respondError(res, 404, "Post not found");
		}
		const buildAction = scheduleBuild(`delete-post:${slug}`);
		return respondJson(res, 200, {
			success: true,
			...buildAction,
			build: serializeBuildState(),
		});
	}

	if (pathname === "/api/admin/assets" && req.method === "GET") {
		return respondJson(res, 200, {
			assets: await listAssets(),
		});
	}

	if (pathname === "/api/admin/assets" && req.method === "POST") {
		const payload = await readJsonBody(req);
		const asset = await writeAsset(payload);
		const buildAction = scheduleBuild(`asset:${asset.path}`);
		return respondJson(res, 200, {
			success: true,
			asset,
			...buildAction,
			build: serializeBuildState(),
		});
	}

	if (pathname === "/api/admin/assets" && req.method === "DELETE") {
		const root = url.searchParams.get("root") || "public";
		const targetPath = url.searchParams.get("path") || "";
		await deleteAsset(root, targetPath);
		const buildAction = scheduleBuild(`delete-asset:${targetPath}`);
		return respondJson(res, 200, {
			success: true,
			...buildAction,
			build: serializeBuildState(),
		});
	}

	return respondError(res, 404, "API route not found");
}

async function resolveStaticFile(pathname) {
	const decodedPath = decodeURIComponent(pathname);
	const cleanPath = decodedPath.replace(/^\/+/, "");
	const directPath = ensureInside(DIST_DIR, path.join(DIST_DIR, cleanPath));
	const directStat = await statSafe(directPath);

	if (directStat?.isFile()) {
		return { filePath: directPath, statusCode: 200 };
	}
	if (directStat?.isDirectory()) {
		const indexPath = path.join(directPath, "index.html");
		if (await statSafe(indexPath)) {
			return { filePath: indexPath, statusCode: 200 };
		}
	}
	if (!path.extname(directPath)) {
		const nestedIndexPath = ensureInside(
			DIST_DIR,
			path.join(DIST_DIR, cleanPath, "index.html"),
		);
		if (await statSafe(nestedIndexPath)) {
			return { filePath: nestedIndexPath, statusCode: 200 };
		}
		const htmlPath = ensureInside(DIST_DIR, path.join(DIST_DIR, `${cleanPath}.html`));
		if (await statSafe(htmlPath)) {
			return { filePath: htmlPath, statusCode: 200 };
		}
	}
	const notFoundPath = path.join(DIST_DIR, "404.html");
	if (await statSafe(notFoundPath)) {
		return { filePath: notFoundPath, statusCode: 404 };
	}
	return null;
}

async function resolveSourceStaticFile(baseDir, routePrefix, pathname) {
	const relativePath = decodeURIComponent(pathname.slice(routePrefix.length));
	const filePath = ensureInside(baseDir, path.join(baseDir, relativePath));
	const stats = await statSafe(filePath);
	if (!stats?.isFile()) {
		return null;
	}
	return filePath;
}

async function serveFile(
	res,
	filePath,
	statusCode = 200,
	cacheControl = "public, max-age=3600",
) {
	const extension = path.extname(filePath).toLowerCase();
	const contentType = MIME_TYPES[extension] || "application/octet-stream";
	const content = await fs.readFile(filePath);
	return respond(res, statusCode, content, {
		"Cache-Control": cacheControl,
		"Content-Type": contentType,
	});
}

async function handleRequest(req, res) {
	try {
		const url = new URL(req.url || "/", `http://${req.headers.host || "localhost"}`);
		if (url.pathname.startsWith("/api/")) {
			return await handleApiRequest(req, res, url);
		}
		if (
			(url.pathname === "/admin/login" || url.pathname === "/cmsadmin/login") &&
			req.method === "POST"
		) {
			return await handleAdminFormLogin(req, res, url);
		}
		if (url.pathname.startsWith(PUBLIC_MEDIA_ROUTE)) {
			const filePath = await resolveSourceStaticFile(
				PUBLIC_ADMIN_ASSETS_DIR,
				PUBLIC_MEDIA_ROUTE,
				url.pathname,
			);
			if (!filePath) {
				return respondError(res, 404, "File not found");
			}
			return await serveFile(res, filePath);
		}
		if (url.pathname.startsWith(CONTENT_MEDIA_ROUTE)) {
			const filePath = await resolveSourceStaticFile(
				POSTS_DIR,
				CONTENT_MEDIA_ROUTE,
				url.pathname,
			);
			if (!filePath) {
				return respondError(res, 404, "File not found");
			}
			return await serveFile(res, filePath);
		}
		const resolved = await resolveStaticFile(url.pathname);
		if (!resolved) {
			return respondError(res, 404, "File not found");
		}
		return await serveFile(
			res,
			resolved.filePath,
			resolved.statusCode,
			path.extname(resolved.filePath).toLowerCase() === ".html"
				? "no-store"
				: "public, max-age=31536000, immutable",
		);
	} catch (error) {
		console.error(error);
		return respondError(
			res,
			500,
			"Internal server error",
			error instanceof Error ? error.message : String(error),
		);
	}
}

await ensureRuntimeFiles();

createServer((req, res) => {
	handleRequest(req, res);
}).listen(PORT, "0.0.0.0", () => {
	console.log(`Firefly admin server listening on http://0.0.0.0:${PORT}`);
});