import * as Effect from "effect/Effect";
import * as Layer from "effect/Layer";
import * as Path from "effect/Path";

import { announcePlatform, Tty } from "../tty.js";

export const layerTty: Layer.Layer<Tty, never, Path.Path> = Layer.effect(Tty)(
	Effect.gen(function* () {
		const path = yield* Path.Path;

		// A no-op here, and called anyway: the rule is that the host layer
		// publishes its own platform, and a host that skips it is a host that
		// works until somebody runs it somewhere `process` is missing.
		announcePlatform(process.platform);

		return {
			isInteractive: Boolean(process.stderr.isTTY),
			// stdin, not stderr: a prompt is read, and `packall … < list.txt` has
			// a terminal to draw on and nothing to read from.
			canPrompt: Boolean(process.stdin.isTTY),
			platform: process.platform,
			columns: process.stderr.columns ?? 80,
			write: (text) => void process.stderr.write(text),
			writeOut: (text) => void process.stdout.write(text),
			// `exitCode` rather than `process.exit`, so pending writes still
			// flush. Killing the process here truncates the very error message
			// that explains what went wrong.
			exit: (code) => {
				process.exitCode = code;
			},
			cwd: process.cwd(),
			path,
		};
	}),
);