import { existsSync, promises as fs } from "node:fs";
import path from "node:path";
import {
	getGamedataRoot,
	getNitroFilesRoot,
} from "@/lib/services/furni-asset-dirs";
import type { OfficialHabboFurniEntry } from "@/lib/services/habbo-furnidata-cache";
import { siteSettings } from "@/lib/services/site-settings";
import type { FurniMetadata } from "@/lib/services/swf-to-nitro";

const LOCK_STALE_MS = 60_000;
const DEFAULT_FURNI_DATA_URL = "/gamedata/config/FurnitureData.json";

/**
 * Resolve the FurnitureData file path from the admin setting
 * `furni_data_url`. The production `/gamedata` mount maps to the configured
 * Gamedata filesystem root; other relative URLs map under public/.
 */
export async function getFurnitureDataPath(): Promise<string> {
	const url =
		(await siteSettings.get("furni_data_url", DEFAULT_FURNI_DATA_URL)) ??
		DEFAULT_FURNI_DATA_URL;
	if (path.isAbsolute(url) && !url.startsWith("/")) return url;
	if (url === "/gamedata" || url.startsWith("/gamedata/")) {
		const gamedataRoot = await getGamedataRoot();
		if (gamedataRoot) {
			const relative = url.replace(/^\/gamedata\/?/, "");
			return path.join(/*turbopackIgnore: true*/ gamedataRoot, relative);
		}
	}
	const relative = url.replace(/^\/+/, "");
	// The `relative` segment is admin-configurable so its concrete value is
	// unknown at build time; without the hint Turbopack traces the entire
	// public/ tree (~400k files) into the route's NFT.
	return path.join(/*turbopackIgnore: true*/ process.cwd(), "public", relative);
}

export async function getFurnitureDataWritePaths(): Promise<string[]> {
	const primary = await getFurnitureDataPath();
	const configuredMirror =
		(await siteSettings.get("furni_data_mirror_path", "")) ?? "";
	const [nitroFilesRoot, gamedataRoot] = await Promise.all([
		getNitroFilesRoot(),
		getGamedataRoot(),
	]);
	const mirror = configuredMirror.trim()
		? configuredMirror
		: nitroFilesRoot
			? path.join(
					/*turbopackIgnore: true*/ nitroFilesRoot,
					"nitro-assets/gamedata/FurnitureData.json",
				)
			: "";

	const gamedataPath = gamedataRoot
		? path.join(
				/*turbopackIgnore: true*/ gamedataRoot,
				"config/FurnitureData.json",
			)
		: "";
	const paths = [primary, mirror, gamedataPath]
		.filter(Boolean)
		.map((p) => path.normalize(p));
	const seen = new Set<string>();
	return paths.filter((p) => {
		const key = process.platform === "win32" ? p.toLowerCase() : p;
		if (seen.has(key)) return false;
		seen.add(key);
		return true;
	});
}

async function getFurnitureDataReadPath(): Promise<string> {
	const paths = await getFurnitureDataWritePaths();
	const existing = paths.find((p) => existsSync(/*turbopackIgnore: true*/ p));
	return existing ?? paths[0];
}

// ── FurnitureData.json lock + helpers ────────────────────────────────

let furniDataLock: Promise<void> = Promise.resolve();

async function acquireDiskLock(lockPath: string): Promise<void> {
	const deadline = Date.now() + 30_000;
	while (true) {
		try {
			const fh = await fs.open(lockPath, "wx");
			await fh.writeFile(String(process.pid));
			await fh.close();
			return;
		} catch (err) {
			const e = err as NodeJS.ErrnoException;
			if (e.code !== "EEXIST") throw err;
			try {
				const stat = await fs.stat(lockPath);
				if (Date.now() - stat.mtimeMs > LOCK_STALE_MS) {
					await fs.unlink(lockPath).catch(() => {});
					continue;
				}
			} catch {
				/* lock vanished between checks */
			}
			if (Date.now() > deadline) throw new Error("FurnitureData lock timeout");
			await new Promise((r) => setTimeout(r, 100));
		}
	}
}

/** Build a map of sprite id → classname from both sections of the furnidata.
 *  If multiple entries share the same id, the first encountered classname wins. */
function furniDataIdOwners(
	data: Record<string, { furnitype: Array<Record<string, unknown>> }>,
): Map<number, string> {
	const owners = new Map<number, string>();
	for (const section of ["roomitemtypes", "wallitemtypes"] as const) {
		for (const e of data[section]?.furnitype ?? []) {
			const id = Number(e?.id);
			if (!Number.isFinite(id) || id <= 0) continue;
			const classname = typeof e?.classname === "string" ? e.classname : "";
			if (!classname) continue;
			if (!owners.has(id)) owners.set(id, classname);
		}
	}
	return owners;
}

/** Assert that no entry in `entries` has a spriteId already used by a different classname
 *  in the existing furnidata or within this batch.  Throws if a conflict is found. */
function assertNoFurniDataIdConflicts(
	existingOwners: Map<number, string>,
	entries: Array<{ entry: Record<string, unknown>; itemType: string }>,
): void {
	const conflicts: string[] = [];
	for (const { entry } of entries) {
		const id = Number(entry?.id);
		if (!Number.isFinite(id) || id <= 0) continue;
		const classname =
			typeof entry?.classname === "string" ? entry.classname : "";
		const existing = existingOwners.get(id);
		if (existing !== undefined && existing !== classname) {
			conflicts.push(
				`spriteId ${id} already used by "${existing}" in FurnitureData.json ` +
					`(attempted "${classname}")`,
			);
			continue;
		}
		// reserve the id within this batch so a second entry with the same id + different classname
		// is also caught (even though the file hasn't been written yet).
		existingOwners.set(id, classname);
	}
	if (conflicts.length > 0) {
		throw new Error(
			`FurnitureData spriteId conflicts: ${conflicts.join("; ")}`,
		);
	}
}

/** Check if a spriteId is already used by a different classname in the local
 *  FurnitureData.json. Returns the existing classname if there's a conflict,
 *  or null if the spriteId is free or the file couldn't be read. */
export async function findFurniDataIdConflict(
	spriteId: number,
	classname: string,
): Promise<string | null> {
	try {
		const furniData = await readFurniData();
		const owners = furniDataIdOwners(
			furniData as Record<
				string,
				{ furnitype: Array<Record<string, unknown>> }
			>,
		);
		const existing = owners.get(spriteId);
		return existing !== undefined && existing !== classname ? existing : null;
	} catch {
		return null; // if file missing/unreadable, treat as no conflict
	}
}

export async function withFurniDataLock<T>(fn: () => Promise<T>): Promise<T> {
	let release!: () => void;
	const acquired = new Promise<void>((r) => {
		release = r;
	});
	const prev = furniDataLock;
	furniDataLock = acquired;
	await prev;
	const lockBase = await getFurnitureDataReadPath();
	await fs.mkdir(path.dirname(lockBase), { recursive: true });
	const lockPath = `${lockBase}.lock`;
	await acquireDiskLock(lockPath);
	try {
		return await fn();
	} finally {
		await fs.unlink(lockPath).catch(() => {});
		release?.();
	}
}

export async function readFurniData(): Promise<Record<string, unknown>> {
	const target = await getFurnitureDataReadPath();
	const raw = await fs.readFile(/*turbopackIgnore: true*/ target, "utf-8");
	return JSON.parse(raw);
}

export async function writeFurniData(
	data: Record<string, unknown>,
): Promise<void> {
	const targets = await getFurnitureDataWritePaths();
	const payload = JSON.stringify(data);
	for (const target of targets) {
		await fs.mkdir(path.dirname(target), { recursive: true });
		const tmp = `${target}.tmp`;
		await fs.writeFile(/*turbopackIgnore: true*/ tmp, payload, "utf-8");
		await fs.rename(/*turbopackIgnore: true*/ tmp, target);
	}
}

export function buildFurniEntry(params: {
	id: number;
	classname: string;
	revision: number;
	category: string;
	name: string;
	description: string;
	spriteId: number;
	dims: { x: number; y: number; z: number };
	metadata: FurniMetadata | null;
	officialHabbo?: OfficialHabboFurniEntry | null;
}): Record<string, unknown> {
	const {
		id,
		classname,
		revision,
		category,
		name,
		description,
		spriteId,
		dims,
		metadata,
		officialHabbo,
	} = params;

	// Prefer the configured official hotel's real hex colors, then .nitro metadata.
	const partcolors = officialHabbo?.partcolors?.color?.length
		? officialHabbo.partcolors
		: (metadata?.partcolors ?? { color: [] });

	return {
		id,
		classname,
		revision: revision || officialHabbo?.revision || 0,
		category: category || officialHabbo?.category || "unknown",
		defaultdir: metadata?.defaultdir ?? officialHabbo?.defaultdir ?? 0,
		xdim: dims.x,
		ydim: dims.y,
		partcolors,
		name,
		description: description || "",
		adurl: "",
		offerid: spriteId,
		buyout: !!officialHabbo?.bc,
		rentofferid: -1,
		rentbuyout: false,
		bc: officialHabbo?.bc ?? false,
		excludeddynamic: false,
		customparams: officialHabbo?.customparams ?? "",
		specialtype: metadata?.specialtype ?? officialHabbo?.specialtype ?? 0,
		canstandon: metadata?.canstandon ?? officialHabbo?.canstandon ?? false,
		cansiton: metadata?.cansiton ?? officialHabbo?.cansiton ?? false,
		canlayon: metadata?.canlayon ?? officialHabbo?.canlayon ?? false,
		furniline: officialHabbo?.furniline ?? "",
		environment: officialHabbo?.environment ?? "",
		rare: officialHabbo?.rare ?? false,
	};
}

function upsertEntryInSection(
	section: { furnitype: Array<Record<string, unknown>> },
	entry: Record<string, unknown>,
) {
	const classname = entry.classname as string | undefined;
	if (classname) {
		const idx = section.furnitype.findIndex((e) => e.classname === classname);
		if (idx >= 0) {
			section.furnitype[idx] = entry;
			return;
		}
	}
	section.furnitype.push(entry);
}

export async function appendFurniEntry(
	entry: Record<string, unknown>,
	itemType: string,
): Promise<void> {
	await withFurniDataLock(async () => {
		const furniData = (await readFurniData()) as Record<
			string,
			{ furnitype: Array<Record<string, unknown>> }
		>;

		// Guard: ensure the spriteId is not already used by a different classname in the file.
		const existingOwners = furniDataIdOwners(furniData);
		assertNoFurniDataIdConflicts(existingOwners, [{ entry, itemType }]);

		if (itemType === "i") {
			if (!furniData.wallitemtypes) furniData.wallitemtypes = { furnitype: [] };
			upsertEntryInSection(furniData.wallitemtypes, entry);
		} else {
			if (!furniData.roomitemtypes) furniData.roomitemtypes = { furnitype: [] };
			upsertEntryInSection(furniData.roomitemtypes, entry);
		}
		await writeFurniData(furniData as Record<string, unknown>);
	});
}

export async function removeFurniEntry(classname: string): Promise<boolean> {
	return withFurniDataLock(async () => {
		const furniData = (await readFurniData()) as Record<
			string,
			{ furnitype: Array<Record<string, unknown>> }
		>;
		let removed = false;

		for (const section of ["roomitemtypes", "wallitemtypes"] as const) {
			if (furniData[section]?.furnitype) {
				const before = furniData[section].furnitype.length;
				furniData[section].furnitype = furniData[section].furnitype.filter(
					(e) => e.classname !== classname,
				);
				if (furniData[section].furnitype.length < before) removed = true;
			}
		}

		if (removed) {
			await writeFurniData(furniData as Record<string, unknown>);
		}
		return removed;
	});
}

/**
 * Patch name/description on existing FurnitureData entries by classname.
 * Optionally creates a minimal entry when missing.
 */
export async function patchFurniEntryNames(
	updates: Array<{
		classname: string;
		itemType: string;
		name?: string;
		description?: string;
		spriteId?: number;
		createIfMissing?: boolean;
	}>,
): Promise<{ updated: number; inserted: number }> {
	if (updates.length === 0) return { updated: 0, inserted: 0 };

	return withFurniDataLock(async () => {
		const furniData = (await readFurniData()) as Record<
			string,
			{ furnitype: Array<Record<string, unknown>> }
		>;
		let updated = 0;
		let inserted = 0;

		for (const u of updates) {
			const sectionKey = u.itemType === "i" ? "wallitemtypes" : "roomitemtypes";
			if (!furniData[sectionKey]) furniData[sectionKey] = { furnitype: [] };
			const section = furniData[sectionKey];
			const idx = section.furnitype.findIndex(
				(e) => e.classname === u.classname,
			);

			if (idx >= 0) {
				const entry = { ...section.furnitype[idx] };
				if (u.name !== undefined) entry.name = u.name;
				if (u.description !== undefined) entry.description = u.description;
				section.furnitype[idx] = entry;
				updated++;
			} else if (u.createIfMissing) {
				section.furnitype.push({
					id: u.spriteId ?? 0,
					classname: u.classname,
					revision: 0,
					category: "unknown",
					name: u.name ?? u.classname,
					description: u.description ?? "",
					offerid: u.spriteId ?? -1,
				});
				inserted++;
			}
		}

		if (updated > 0 || inserted > 0) {
			await writeFurniData(furniData as Record<string, unknown>);
		}
		return { updated, inserted };
	});
}

export async function appendFurniEntriesBatch(
	entries: Array<{ entry: Record<string, unknown>; itemType: string }>,
): Promise<void> {
	await withFurniDataLock(async () => {
		const furniData = (await readFurniData()) as Record<
			string,
			{ furnitype: unknown[] }
		>;

		// Guard: ensure no spriteId conflicts with existing file entries
		// or within this batch (same id + different classname).
		const existingOwners = furniDataIdOwners(
			furniData as Record<
				string,
				{ furnitype: Array<Record<string, unknown>> }
			>,
		);
		assertNoFurniDataIdConflicts(existingOwners, entries);

		for (const { entry, itemType } of entries) {
			if (itemType === "i") {
				if (!furniData.wallitemtypes)
					furniData.wallitemtypes = { furnitype: [] };
				upsertEntryInSection(
					furniData.wallitemtypes as {
						furnitype: Array<Record<string, unknown>>;
					},
					entry,
				);
			} else {
				if (!furniData.roomitemtypes)
					furniData.roomitemtypes = { furnitype: [] };
				upsertEntryInSection(
					furniData.roomitemtypes as {
						furnitype: Array<Record<string, unknown>>;
					},
					entry,
				);
			}
		}
		await writeFurniData(furniData as Record<string, unknown>);
	});
}