/*!
 * V4Fire Core
 * https://github.com/V4Fire/Core
 *
 * Released under the MIT license
 * https://github.com/V4Fire/Core/blob/master/LICENSE
 */

/**
 * [[include:core/semver/README.md]]
 * @packageDocumentation
 */

import { operations, compareRgxp, operandLengthErrorText } from 'core/semver/const';
import type { Operation, Strategy, ComparisonOptions } from 'core/semver/interface';

export * from 'core/semver/const';
export * from 'core/semver/interface';

/**
 * Compares two strings with number versions (a <op> b) by using the semver strategy
 *
 * @param a
 * @param b
 * @param op - operation type
 * @param [opts] - additional options for the specified operation
 */
export default function compare(a: string, b: string, op: Operation, opts: ComparisonOptions = {x: '*'}): boolean {
	if (a.trim() === '' || b.trim() === '') {
		throw new Error(operandLengthErrorText);
	}

	if (!(op in operations)) {
		throw new TypeError(`Unknown comparator "${op}". Only "${Object.keys(operations).join(', ')}" available.`);
	}

	const
		left = a.split('.'),
		right = b.split('.'),
		{x} = opts;

	const
		strategyMatch = compareRgxp.exec(op);

	let
		strategy: Strategy = 'ord';

	if (strategyMatch?.[0] === op) {
		strategy = 'range';

	} else if (strategyMatch?.index === 0) {
		// Using for the equal ==
		strategy = 'eq';
	}

	const
		max = Math.max(left.length, right.length);

	let
		prevRes = false,
		res = false;

	for (let i = 0; i < max; i++) {
		const
			l = left[i] ?? x,
			r = right[i] ?? x;

		const
			rVal = parseInt(r, 10),
			lVal = parseInt(l, 10);

		if (i > 0) {
			prevRes = res;
		}

		res = operations[op](
			lVal,
			rVal
		);

		switch (strategy) {
			case 'range':
				if (!res) {
					if (op.startsWith('~')) {
						return l === x || r === x || i > 0 && rVal < lVal;
					}

					return i > 0 && right[i - 1] !== '0' && rVal < lVal || l === x || r === x;
				}

				break;

			case 'eq':
				if (!res) {
					return l === x || r === x;
				}

				break;

			case 'ord':
				if (!res && (r === x || l === x)) {
					// 1.3.0 <= >= 1.2.*
					if (op.length === 2 && !prevRes) {
						return false;
					}

					// 1.2.4 >< 1.*
					// 1.2.4 >< 1.2.*
					// 1.* >< 1.2.4
					// 1.2.* >< 1.2.4
					return op.length !== 1;
				}

				// 1.2.1 <= 1.1.1
				// 2.1.1 <= 1.1.1
				// 1.1.1 >= 1.2.1
				// 1.1.1 >= 2.1.1
				if (!res && op.length === 2) {
					return res;
				}

				// 1.1.2 > 1.2.1
				// 1.2.2 > 2.1.1
				if (!res && op.length === 1 && rVal !== lVal) {
					return res;
				}

				// 1.1.2 <= 1.2.1
				// 1.2.2 <= 2.1.1
				if (res && op.length === 2 && rVal !== lVal) {
					return res;
				}

				// 1.1.2 > 1.1.1
				// 1.3.0 > 1.2.*
				if (res && op.length === 1) {
					return res;
				}

				break;

			default:
				throw new TypeError('Unsupported operation');
		}
	}

	return res;
}