import { add } from "./add.js";
import compare from "./compare.js";
import { parseStringNumber, addOne, subtractOne } from "./utils";
/**
* Rounds down to the nearest integer (towards negative infinity)
* @param num Number as string
* @returns Floor value as string
*/
export function floor(num: string): string {
const parsed = parseStringNumber(num);
// If no fractional part, return the number as is
if (!parsed.fractionalPart || parsed.fractionalPart === "") {
return parsed.sign === -1 && parsed.integerPart !== "0" ? "-" + parsed.integerPart : parsed.integerPart;
}
// If positive, just return integer part
if (parsed.sign === 1) {
return parsed.integerPart;
}
// If negative, subtract 1 from integer part
const decremented = addOne(parsed.integerPart);
return "-" + decremented;
}
/**
* Rounds up to the nearest integer (towards positive infinity)
* @param num Number as string
* @returns Ceiling value as string
*/
export function ceil(num: string): string {
const parsed = parseStringNumber(num);
// If no fractional part, return the number as is
if (!parsed.fractionalPart || parsed.fractionalPart === "") {
return parsed.sign === -1 && parsed.integerPart !== "0" ? "-" + parsed.integerPart : parsed.integerPart;
}
// If negative, just return integer part (with sign)
if (parsed.sign === -1) {
return "-" + parsed.integerPart;
}
// If positive, add 1 to integer part
const incremented = addOne(parsed.integerPart);
return incremented;
}
/**
* Removes the fractional part (rounds towards zero)
* @param num Number as string
* @returns Truncated value as string
*/
export function truncate(num: string): string {
const parsed = parseStringNumber(num);
// Return just the integer part with appropriate sign
if (parsed.sign === -1 && parsed.integerPart !== "0") {
return "-" + parsed.integerPart;
}
return parsed.integerPart;
}
/**
* Rounds to the nearest integer using "round half up" strategy
* @param num Number as string
* @returns Rounded value as string
*/
export function round(num: string): string {
const parsed = parseStringNumber(num);
// If no fractional part, return the number as is
if (!parsed.fractionalPart || parsed.fractionalPart === "") {
return parsed.sign === -1 && parsed.integerPart !== "0" ? "-" + parsed.integerPart : parsed.integerPart;
}
// Check first digit of fractional part for rounding decision
const firstFracDigit = parsed.fractionalPart[0];
let firstFracValue = 0;
if (firstFracDigit >= "0" && firstFracDigit <= "9") {
firstFracValue = firstFracDigit.charCodeAt(0) - "0".charCodeAt(0);
}
// If first fractional digit is < 5, truncate
if (firstFracValue < 5) {
return truncate(num);
}
// If first fractional digit is >= 5, round up
if (parsed.sign === 1) {
// Positive number: add 1 to integer part
const incremented = addOne(parsed.integerPart);
return incremented;
} else {
// Negative number: subtract 1 from absolute value (making it more negative)
const incremented = addOne(parsed.integerPart);
return "-" + incremented;
}
}
/**
* Rounds to specified number of decimal places
* @param num Number as string
* @param precision Number of decimal places
* @returns Rounded value as string
*/
export function roundToPrecision(num: string, precision: number): string {
if (precision < 0) {
throw new Error("Precision must be non-negative");
}
const parsed = parseStringNumber(num);
// If no fractional part and precision > 0, add zeros
if (!parsed.fractionalPart || parsed.fractionalPart === "") {
if (precision === 0) {
return parsed.sign === -1 && parsed.integerPart !== "0" ? "-" + parsed.integerPart : parsed.integerPart;
}
const zeros = "0".repeat(precision);
const result = parsed.integerPart + "." + zeros;
return parsed.sign === -1 && parsed.integerPart !== "0" ? "-" + result : result;
}
// If precision is 0, use regular round function
if (precision === 0) {
return round(num);
}
// If fractional part is shorter than precision, pad with zeros
if (parsed.fractionalPart.length <= precision) {
const paddedFrac = parsed.fractionalPart.padEnd(precision, "0");
const result = parsed.integerPart + "." + paddedFrac;
return parsed.sign === -1 && parsed.integerPart !== "0" ? "-" + result : result;
}
// Get the digit at precision position for rounding decision
const roundingDigit = parsed.fractionalPart[precision];
let roundingValue = 0;
if (roundingDigit >= "0" && roundingDigit <= "9") {
roundingValue = roundingDigit.charCodeAt(0) - "0".charCodeAt(0);
}
// Take the required precision digits
let resultFrac = parsed.fractionalPart.substring(0, precision);
let resultInt = parsed.integerPart;
// Round if needed
if (roundingValue >= 5) {
// Create a number from integer + fractional parts for rounding
const combinedNumber = resultInt + resultFrac;
const incrementedNumber = addOne(combinedNumber);
// Split back into integer and fractional parts
if (incrementedNumber.length > combinedNumber.length) {
// Carry occurred, integer part grew
resultInt = incrementedNumber.substring(0, incrementedNumber.length - precision);
resultFrac = incrementedNumber.substring(incrementedNumber.length - precision);
} else {
resultInt = incrementedNumber.substring(0, incrementedNumber.length - precision);
resultFrac = incrementedNumber.substring(incrementedNumber.length - precision);
}
}
// Remove trailing zeros from fractional part
resultFrac = resultFrac.replace(/0+$/, "");
// Construct result
let result = resultInt;
if (resultFrac !== "") {
result += "." + resultFrac;
}
return parsed.sign === -1 && result !== "0" ? "-" + result : result;
}