import fs from "fs";
import kleur from "kleur";
import { stripIndent } from "common-tags";
import { saveConfig, readConfig } from "./io/config.js";
import toFixed from "./utils/toFixed.js";
import getDayData from "./utils/getDayData.js";

type Tests = {
	name?: string;
	input: string;
	expected: string | number | bigint | void;
}[];

type Solution = (
	input: string,
	testName?: string,
) => string | number | bigint | void;

type Solutions = {
	part1?: {
		solution: Solution;
		tests?: Tests;
	};
	part2?: {
		solution: Solution;
		tests?: Tests;
		testsPending?: Tests; // Only used so I can rename after fetching tests for part 2.
	};
	trimTestInputs?: boolean;
	onlyTests?: boolean;
};

const runTests = async (
	tests: Tests,
	solution: Solution,
	part: 1 | 2,
	trimTestInputs = true,
) => {
	for (let i = 0; i < tests.length; i++) {
		const { name, input, expected } = tests[i];

		const data = trimTestInputs ? stripIndent(input) : input;

		const testName = `Part ${part}, test ${i + 1}${
			name ? `, ${name}` : ""
		}`;
		const result = await solution(data, testName);

		if (result === expected) {
			console.log(kleur.green(`${testName} - passed with result: ${result}`));
		} else {
			console.log(kleur.red(`${testName} - failed`));
			console.log(`\nResult:`);
			console.dir(result);
			console.log(`\nExpected:`);
			console.dir(expected);
			console.log();
		}
	}
};

const runSolution = async (solution: Solution, input: string, part: 1 | 2) => {
	const t0 = process.hrtime.bigint();
	const result = await solution(input);
	const t1 = process.hrtime.bigint();
	const time = Number(t1 - t0) / 1e6;

	if (!["string", "number", "bigint", "undefined"].includes(typeof result)) {
		console.log(
			kleur.yellow(
				`Warning - the result type of part ${part} should be a string, a number or a bigint, got:`,
			),
			kleur.red(typeof result),
		);
	}

	console.log(`\nPart ${part} (in ${toFixed(time)}ms):`);

	if (typeof result === "string" && /\n/.test(result)) {
		console.log(result);
	} else {
		console.dir(result);
	}

	return { result, time };
};

const runAsync = async (
	solutions: Solutions,
	inputFile: string,
	year: number,
	day: number,
) => {
	const config = readConfig();

	if (solutions?.part1?.tests) {
		await runTests(
			solutions.part1.tests,
			solutions.part1.solution,
			1,
			solutions.trimTestInputs,
		);
	}

	if (solutions?.part2?.tests) {
		await runTests(
			solutions.part2.tests,
			solutions.part2.solution,
			2,
			solutions.trimTestInputs,
		);
	}

	if (solutions.onlyTests) {
		return;
	}

	const input = fs.readFileSync(inputFile).toString();

	let output1;
	let output2;
	let totalTime = 0;

	if (solutions.part1) {
		output1 = await runSolution(solutions.part1.solution, input, 1);
		totalTime += output1.time;
	}

	if (solutions.part2) {
		output2 = await runSolution(solutions.part2.solution, input, 2);
		totalTime += output2.time;
	}

	console.log(`\nTotal time: ${toFixed(totalTime)}ms`);
	const configYear = config.years.find(y => y.year === year)!;
	configYear.days[day - 1].part1.result =
		output1?.result === undefined ? null : String(output1.result);

	configYear.days[day - 1].part1.time =
		output1?.result === undefined ? null : output1.time;

	configYear.days[day - 1].part2.result =
		output2?.result === undefined ? null : String(output2.result);

	configYear.days[day - 1].part2.time =
		output2?.result === undefined ? null : output2.time;

	saveConfig(config);
};

const run = (solutions: Solutions, customInputFile?: string) => {
	let year = null;
	let day = null;
	let inputFile = null;

	if (customInputFile) {
		const dayName = (customInputFile.match(/day\d\d/) || [])[0];
		inputFile = customInputFile;
		day = dayName ? Number(dayName.slice(-2)) : null;
		// Don't have year parsed here, need to figure out how this funciton is used
	} else {
		const dayData = getDayData();
		year = dayData.year;
		day = dayData.day;
		inputFile = dayData.inputFile;
	}

	if (inputFile === null) {
		console.log(
			kleur.red(stripIndent`
        Couldn't detect the day directory!

        Please make sure that the day folder is named "dayXX",
        where each X means number from 0 to 9.
      `),
		);
		return;
	}

	if (year === null) {
		console.log(
			kleur.red(stripIndent`
        Couldn't detect the year number!

        Make sure that your directory contains the year number
        in format "XXXX" from 2015 to the current year.
      `),
		);
		return;
	}

	if (day === null) {
		console.log(
			kleur.red(stripIndent`
        Couldn't detect the day number!

        Make sure that your directory or file name contains the day number
        in format "dayXX", where each X means number from 0 to 9.
      `),
		);
		return;
	}

	if (!fs.existsSync(inputFile)) {
		console.log(
			kleur.red(stripIndent`
        There is no "input.txt" file in the solution directory!
        
        Please add the file or specify custom file location
        via the second argument of the \`run\` function.
      `),
		);
		return;
	}

	runAsync(solutions, inputFile, year, day);
};

export default run;