'use strict';

/**
 * Formats a number as plain digits with dot as decimal separator.
 * @param {Decimal|string|number} num
 * @param {number} minPrecision - Minimum decimal places
 * @param {number} maxPrecision - Maximum decimal places
 * @returns {string} Formatted number string
 */
function prettyNumber(num, minPrecision, maxPrecision) {
	minPrecision = minPrecision || 4;
	maxPrecision = maxPrecision || 10;
	const val = num instanceof Decimal ? num.toNumber() : Number(num);
	if (!Number.isFinite(val)) {
		return '';
	}
	let d;
	try {
		d = new Decimal(num);
	} catch (e) {
		return '';
	}
	const absVal = d.abs();
	// Larger numbers need fewer decimal places for readable output;
	// smaller numbers get more to stay meaningful.
	let precision = maxPrecision;
	if (absVal.gte(10000)) {
		precision = 2;
	} else if (absVal.gte(1000)) {
		precision = 4;
	} else if (absVal.gte(1)) {
		precision = 6;
	} else if (absVal.gte(0.001)) {
		precision = 8;
	}
	precision = Math.max(minPrecision,
		Math.min(precision, maxPrecision));
	let str = d.toFixed(precision);
	if (str.indexOf('.') !== -1) {
		str = str.replace(/0+$/, '');
		str = str.replace(/\.$/, '');
	}
	return str;
}

/**
 * Parses a German number string.
 * Accepts both comma and dot as decimal separator.
 * @param {string} input
 * @returns {string} Normalized string with dot as decimal
 */
function parseNumber(input) {
	if (!input) return '0';
	const hasComma = input.indexOf(',') !== -1;
	const hasDot = input.indexOf('.') !== -1;
	if (hasComma && hasDot) {
		return input.replace(/\./g, '').replace(/,/g, '.') || '0';
	}
	return input.replace(/,/g, '.') || '0';
}

/**
 * Prepares input value for conversion.
 * Returns a Decimal, or 1 if input is empty.
 * @param {string} input - User input from field
 * @returns {Decimal} Prepared value
 */
function prepareValue(input) {
	if (!input || input.trim() === '') {
		return new Decimal(1);
	}
	return new Decimal(input.replace(/,/g, '.'));
}

/**
 * Updates the URL with the current input value.
 * @param {string} value - The input value
 */
function updateUrl(value) {
	const normalized = value ? value.replace(/,/g, '.') : '';
	if (normalized && normalized !== '0') {
		history.replaceState(null, '', '?v=' + normalized);
	} else {
		history.replaceState(null, '', '?v=1');
	}
}

/**
 * Navigates to a new URL with the current input value as parameter.
 * @param {string} url - Target URL
 * @param {string} value - Current input value
 */
function navigate(url, value) {
	const normalized = value ? value.replace(/,/g, '.') : '1';
	window.location.href = url + '?v=' + normalized;
}