"use strict";

const tape = require("tape-catch");
const fs = require("fs");
const path = require("path");
const util = require("util");
const evaluate = require("../src/evaluate");

const NIX_SOURCE_REPO = process.env.NIX_SOURCE_REPO;

if (NIX_SOURCE_REPO == null) {
	throw new Error(`To run the upstream Nix language tests, you must specify a NIX_SOURCE_REPO environment variable, that points at the root of a local checkout of the Git repository for Nix`);
}

const testsPath = path.join(NIX_SOURCE_REPO, "tests/lang");

let tests = fs.readdirSync(testsPath)
	.filter((entry) => entry.endsWith(".exp"))
	.map((entry) => entry.replace(/\.exp$/, ""));

function formatResultNode(node) {
	if (typeof node === "string") {
		return `"${node.replace(/"/g, '\\"')}"`;
	} else if (Array.isArray(node)) {
		return `[ ${node.map(formatResultNode).join(" ")} ]`;
	} else {
		return node.toString();
	}
}

for (let test of tests) {
	try {
		let expression = fs.readFileSync(path.join(testsPath, `${test}.nix`), "utf8");
		let expectedResult = fs.readFileSync(path.join(testsPath, `${test}.exp`), "utf8").replace(/\n$/, "");

		tape(`Nix upstream language tests - ${test}`, (test) => {
			test.plan(1);

			let result = formatResultNode(evaluate(expression).value);

			test.equals(expectedResult, result);
		});
	} catch (error) {
		// FIXME: This would currently cause ENOENTs during evaluation (eg. reading a file from Nix itself) to be ignored
		if (error.code === "ENOENT") {
			// skip
		} else {
			throw error;
		}
	}
}