import { throwParseError } from "./errors.js";
import { anchoredRegex, RegexPatterns } from "./strings.js";
/*
 * The goal of the number literal and bigint literal regular expressions is to:
 *
 *   1. Ensure definitions form a bijection with the values they represent.
 *   2. Attempt to mirror TypeScript's own format for stringification of numeric
 *      values such that the regex should match a given definition if any only if
 *      a precise literal type will be inferred (in TS4.8+).
 */
const anchoredNegativeZeroPattern = /^-0\.?0*$/.source;
const positiveIntegerPattern = /[1-9]\d*/.source;
const looseDecimalPattern = /\.\d+/.source;
const strictDecimalPattern = /\.\d*[1-9]/.source;
const createNumberMatcher = (opts) => anchoredRegex(RegexPatterns.negativeLookahead(anchoredNegativeZeroPattern) +
    RegexPatterns.nonCapturingGroup("-?" +
        RegexPatterns.nonCapturingGroup(RegexPatterns.nonCapturingGroup("0|" + positiveIntegerPattern) +
            RegexPatterns.nonCapturingGroup(opts.decimalPattern) +
            "?") +
        (opts.allowDecimalOnly ? "|" + opts.decimalPattern : "") +
        "?"));
/**
 *  Matches a well-formatted numeric expression according to the following rules:
 *    1. Must include an integer portion (i.e. '.321' must be written as '0.321')
 *    2. The first digit of the value must not be 0, unless the entire integer portion is 0
 *    3. If the value includes a decimal, its last digit may not be 0
 *    4. The value may not be "-0"
 */
export const wellFormedNumberMatcher = createNumberMatcher({
    decimalPattern: strictDecimalPattern,
    allowDecimalOnly: false
});
export const isWellFormedNumber = wellFormedNumberMatcher.test.bind(wellFormedNumberMatcher);
/**
 * Similar to wellFormedNumber but more permissive in the following ways:
 *
 *  - Allows numbers without an integer portion like ".5" (well-formed equivalent is "0.5")
 *  - Allows decimals with trailing zeroes like "0.10" (well-formed equivalent is "0.1")
 */
export const numericStringMatcher = createNumberMatcher({
    decimalPattern: looseDecimalPattern,
    allowDecimalOnly: true
});
export const isNumericString = numericStringMatcher.test.bind(numericStringMatcher);
export const numberLikeMatcher = /^-?\d*\.?\d*$/;
const isNumberLike = (s) => s.length !== 0 && numberLikeMatcher.test(s);
/**
 *  Matches a well-formatted integer according to the following rules:
 *    1. must begin with an integer, the first digit of which cannot be 0 unless the entire value is 0
 *    2. The value may not be "-0"
 */
export const wellFormedIntegerMatcher = anchoredRegex(RegexPatterns.negativeLookahead("^-0$") +
    "-?" +
    RegexPatterns.nonCapturingGroup(RegexPatterns.nonCapturingGroup("0|" + positiveIntegerPattern)));
export const isWellFormedInteger = wellFormedIntegerMatcher.test.bind(wellFormedIntegerMatcher);
export const integerLikeMatcher = /^-?\d+$/;
const isIntegerLike = integerLikeMatcher.test.bind(integerLikeMatcher);
const numericLiteralDescriptions = {
    number: "a number",
    bigint: "a bigint",
    integer: "an integer"
};
export const writeMalformedNumericLiteralMessage = (def, kind) => `'${def}' was parsed as ${numericLiteralDescriptions[kind]} but could not be narrowed to a literal value. Avoid unnecessary leading or trailing zeros and other abnormal notation`;
const isWellFormed = (def, kind) => kind === "number" ? isWellFormedNumber(def) : isWellFormedInteger(def);
const parseKind = (def, kind) => kind === "number" ? Number(def) : Number.parseInt(def);
const isKindLike = (def, kind) => kind === "number" ? isNumberLike(def) : isIntegerLike(def);
export const tryParseNumber = (token, options) => parseNumeric(token, "number", options);
export const tryParseWellFormedNumber = (token, options) => parseNumeric(token, "number", { ...options, strict: true });
export const tryParseInteger = (token, options) => parseNumeric(token, "integer", options);
const parseNumeric = (token, kind, options) => {
    const value = parseKind(token, kind);
    if (!Number.isNaN(value)) {
        if (isKindLike(token, kind)) {
            if (options?.strict) {
                return isWellFormed(token, kind) ? value : (throwParseError(writeMalformedNumericLiteralMessage(token, kind)));
            }
            return value;
        }
    }
    return (options?.errorOnFail ?
        throwParseError(options?.errorOnFail === true ?
            `Failed to parse ${numericLiteralDescriptions[kind]} from '${token}'`
            : options?.errorOnFail)
        : undefined);
};
export const tryParseWellFormedBigint = (def) => {
    if (def[def.length - 1] !== "n")
        return;
    const maybeIntegerLiteral = def.slice(0, -1);
    let value;
    try {
        value = BigInt(maybeIntegerLiteral);
    }
    catch {
        return;
    }
    if (wellFormedIntegerMatcher.test(maybeIntegerLiteral))
        return value;
    if (integerLikeMatcher.test(maybeIntegerLiteral)) {
        // If the definition looks like a bigint but is
        // not well-formed, throw.
        return throwParseError(writeMalformedNumericLiteralMessage(def, "bigint"));
    }
};
/**
 * Returns the next or previous representable floating-point number after the given input.
 *
 * @param {"+" | "-"} [direction="+"] - The direction to find the nearest float. "+" for the next float, "-" for the previous float.
 * @throws {Error} If the input is not a finite number.
 *
 * @example
 * console.log(nearestFloat(0)); // Smallest positive number
 * console.log(nearestFloat(2)); // 2.0000000000000004
 * console.log(nearestFloat(2.1)); // 2.1000000000000005
 * console.log(nearestFloat(2, "-")); // 1.9999999999999998
 * console.log(nearestFloat(2.1, "-")); // 2.0999999999999996
 * // as size of input increases, the increments become larger to stay within what
 * // JS can represent in a numeric value
 * console.log(nearestFloat(5555555555555555)); // 5555555555555556
 * console.log(nearestFloat(5555555555555555, "-")); // 5555555555555554
 */
export const nearestFloat = (n, direction = "+") => {
    const buffer = new ArrayBuffer(8);
    const f64 = new Float64Array(buffer);
    const u32 = new Uint32Array(buffer);
    f64[0] = n;
    if (n === 0) {
        u32[0] = 1;
        u32[1] = direction === "-" ? 1 << 31 : 0;
    }
    else if ((n > 0 && direction === "+") || (n < 0 && direction === "-")) {
        if (u32[0]++ === 0xffffffff)
            u32[1]++;
    }
    else if (u32[0]-- === 0)
        u32[1]--;
    return f64[0];
};