import { existsSync, mkdirSync, readFileSync, writeFileSync } from "node:fs";
import { dirname } from "node:path";
import { webPreferencesPath } from "../../../../src/app-paths.ts";

export const runtime = "nodejs";
export const dynamic = "force-dynamic";

/** Shape of persisted web preferences. */
interface WebPreferences {
	devRoot?: string;
	lastActiveProject?: string;
}

// ─── GET: read current preferences ─────────────────────────────────────────

export async function GET(): Promise<Response> {
	try {
		if (!existsSync(webPreferencesPath)) {
			return Response.json({});
		}
		const raw = readFileSync(webPreferencesPath, "utf-8");
		const prefs: WebPreferences = JSON.parse(raw);
		return Response.json(prefs);
	} catch {
		// File corrupt or unreadable — return empty
		return Response.json({});
	}
}

// ─── PUT: write preferences ────────────────────────────────────────────────

export async function PUT(request: Request): Promise<Response> {
	try {
		const body = (await request.json()) as Record<string, unknown>;

		// Read existing prefs to merge (don't clobber fields not in this request)
		let existing: WebPreferences = {};
		try {
			if (existsSync(webPreferencesPath)) {
				existing = JSON.parse(readFileSync(webPreferencesPath, "utf-8"));
			}
		} catch {
			// Corrupt file — start fresh
		}

		// Merge only provided keys
		const prefs: WebPreferences = { ...existing };
		if (typeof body.devRoot === "string") {
			prefs.devRoot = body.devRoot;
		}
		if (typeof body.lastActiveProject === "string") {
			prefs.lastActiveProject = body.lastActiveProject;
		}

		// Ensure parent directory exists
		const dir = dirname(webPreferencesPath);
		if (!existsSync(dir)) {
			mkdirSync(dir, { recursive: true });
		}

		writeFileSync(webPreferencesPath, JSON.stringify(prefs, null, 2), "utf-8");
		return Response.json(prefs);
	} catch (err) {
		return Response.json(
			{
				error: `Failed to write preferences: ${err instanceof Error ? err.message : String(err)}`,
			},
			{ status: 500 },
		);
	}
}