import { padNumber } from "./padNumber";

/**
 * Generates an array of formatted numbers for a number picker, with support for infinite scroll,
 * padding, and number repetition.
 *
 * @param {number} numberOfItems - Total number of items to generate
 * @param {Object} options - Configuration options for number generation
 * @param {boolean} [options.disableInfiniteScroll] - Whether to disable infinite scroll
 * @param {number} options.interval - The interval between consecutive numbers
 * @param {boolean} [options.padNumbersWithZero] - Whether to pad single-digit numbers with leading zeros
 * @param {number} options.padWithNItems - Number of empty items to pad with
 * @param {number} options.repeatNTimes - How many times to repeat the number sequence
 *
 * @returns {string[]} Array of formatted number strings
 *
 * @example
 * // Generate numbers 0-9 with padding
 * generateNumbers(10, {
 *   interval: 1,
 *   padWithNItems: 2,
 *   repeatNTimes: 1,
 *   padNumbersWithZero: true
 * })
 * // Returns: ['', '', '00', '01', '02', '03', '04', '05', '06', '07', '08', '09', '', '']
 *
 * @example
 * // Generate even numbers with infinite scroll
 * generateNumbers(5, {
 *   interval: 2,
 *   padWithNItems: 2,
 *   repeatNTimes: 3,
 *   disableInfiniteScroll: false
 * })
 * // Returns: ['0', '2', '4', '6', '8', '0', '2', '4', '6', '8', '0', '2', '4', '6', '8']
 */
export const generateNumbers = (
  numberOfItems: number,
  options: {
    disableInfiniteScroll?: boolean;
    interval: number;
    padNumbersWithZero?: boolean;
    padWithNItems: number;
    repeatNTimes: number;
  }
) => {
  if (numberOfItems <= 0) {
    return [];
  }

  let numbers: string[] = [];
  for (let i = 0; i < numberOfItems; i++) {
    const value = i * options.interval;
    numbers.push(padNumber(value, { padWithZero: options.padNumbersWithZero }));
  }

  if (options.repeatNTimes > 1) {
    numbers = Array(options.repeatNTimes).fill(numbers).flat();
  }
  if (options.disableInfiniteScroll || options.repeatNTimes === 1) {
    numbers.push(...Array(options.padWithNItems).fill(""));
    numbers.unshift(...Array(options.padWithNItems).fill(""));
  }
  return numbers;
};

/**
 * Generates an array of formatted 12-hour time strings (AM/PM) for a time picker.
 * Supports infinite scroll, padding, and number repetition.
 *
 * @param {Object} options - Configuration options for time generation
 * @param {boolean} [options.disableInfiniteScroll] - Whether to disable infinite scroll
 * @param {number} options.interval - The interval between hours (must be a divisor of 12)
 * @param {boolean} [options.padNumbersWithZero] - Whether to pad single-digit hours with leading zeros
 * @param {number} options.padWithNItems - Number of empty items to pad with
 * @param {number} [options.repeatNTimes] - How many times to repeat the time sequence (defaults to 1)
 *
 * @returns {string[]} Array of formatted 12-hour time strings
 *
 * @example
 * // Generate hours with 1-hour interval
 * generate12HourNumbers({
 *   interval: 1,
 *   padWithNItems: 2,
 *   padNumbersWithZero: true
 * })
 * // Returns: ['', '', '12 AM', '01 AM', '02 AM', ..., '11 PM', '', '']
 *
 * @example
 * // Generate hours with 2-hour interval and infinite scroll
 * generate12HourNumbers({
 *   interval: 2,
 *   padWithNItems: 2,
 *   repeatNTimes: 2,
 *   disableInfiniteScroll: false
 * })
 * // Returns: ['12 AM', '2 AM', '4 AM', ..., '10 PM', '12 AM', '2 AM', ...]
 */
export const generate12HourNumbers = (options: {
  disableInfiniteScroll?: boolean;
  interval: number;
  padNumbersWithZero?: boolean;
  padWithNItems: number;
  repeatNTimes?: number;
}) => {
  let numbers: string[] = [];

  // Generate numbers from 12 AM to 11 AM
  for (let i = 0; i < 12; i += options.interval) {
    const hour = i === 0 ? 12 : i;
    numbers.push(`${padNumber(hour, { padWithZero: options.padNumbersWithZero })} AM`);
  }

  // Generate numbers from 12 PM to 11 PM
  for (let i = 12; i < 24; i += options.interval) {
    const hour = i > 12 ? i - 12 : i;
    numbers.push(`${padNumber(hour, { padWithZero: options.padNumbersWithZero })} PM`);
  }

  if ((options.repeatNTimes ?? 1) > 1) {
    numbers = Array(options.repeatNTimes).fill(numbers).flat();
  }

  if (options.disableInfiniteScroll) {
    numbers.push(...Array(options.padWithNItems).fill(""));
    numbers.unshift(...Array(options.padWithNItems).fill(""));
  }

  return numbers;
};

/**
 * Generates an array of formatted hour strings for the 12-hour clock cycle (no AM/PM suffix),
 * intended for the hours column when the AM/PM column is rendered separately.
 *
 * Index 0 always represents the noon/midnight slot and displays as "12"; subsequent indices
 * follow the supplied interval starting from 1. Internal value 0 → "12", value k → display k.
 *
 * @example
 * // Generate the full 12-hour cycle padded with zeros
 * generate12HourCycleNumbers({
 *   interval: 1,
 *   padWithNItems: 0,
 *   padNumbersWithZero: true,
 *   repeatNTimes: 1,
 *   disableInfiniteScroll: true,
 * })
 * // Returns: ['12', '01', '02', ..., '11']
 */
export const generate12HourCycleNumbers = (options: {
  disableInfiniteScroll?: boolean;
  interval: number;
  padNumbersWithZero?: boolean;
  padWithNItems: number;
  repeatNTimes: number;
}) => {
  let numbers: string[] = [];

  for (let i = 0; i < 12; i += options.interval) {
    const hour = i === 0 ? 12 : i;
    numbers.push(padNumber(hour, { padWithZero: options.padNumbersWithZero }));
  }

  if (options.repeatNTimes > 1) {
    numbers = Array(options.repeatNTimes).fill(numbers).flat();
  }

  if (options.disableInfiniteScroll || options.repeatNTimes === 1) {
    numbers.push(...Array(options.padWithNItems).fill(""));
    numbers.unshift(...Array(options.padWithNItems).fill(""));
  }

  return numbers;
};

/**
 * Generates the items shown in the standalone AM/PM picker column. The column is non-looping
 * and always padded so that AM and PM line up with the centre row.
 *
 * @example
 * generateAmPmItems({ amLabel: 'AM', pmLabel: 'PM', padWithNItems: 1 })
 * // Returns: ['', 'AM', 'PM', '']
 */
export const generateAmPmItems = (options: {
  amLabel: string;
  padWithNItems: number;
  pmLabel: string;
}) => {
  const padding: string[] = Array(options.padWithNItems).fill("");
  return [...padding, options.amLabel, options.pmLabel, ...padding];
};