import { IFileSystem } from "@/ports";

export class InMemoryFileSystem implements IFileSystem {
	private files = new Map<string, string>();

	reset(): void {
		this.files.clear();
	}

	async readFile(path: string): Promise<string> {
		const content = this.files.get(path);
		if (content === undefined) {
			throw new Error(`ENOENT: no such file: ${path}`);
		}
		return content;
	}

	async writeFile(path: string, content: string): Promise<void> {
		this.files.set(path, content);
	}

	async deleteFile(path: string): Promise<void> {
		this.files.delete(path);
	}

	async readdir(path: string): Promise<string[]> {
		const prefix = path.endsWith("/") || path.endsWith("\\") ? path : path + "/";
		const seen = new Set<string>();
		for (const key of this.files.keys()) {
			if (key.startsWith(prefix)) {
				const relative = key.slice(prefix.length);
				const top = relative.split(/[/\\]/)[0];
				if (top) seen.add(top);
			}
		}
		return [...seen];
	}

	async mkdir(_path: string): Promise<void> {
		// no-op for in-memory
	}
}