import { Time } from './timepicker.models';

const dex = 10;
const hoursPerDay = 24;
const hoursPerDayHalf = 12;
const minutesPerHour = 60;
const secondsPerMinute = 60;

export function isValidDate(value?: string | Date): boolean {
  if (!value) {
    return false;
  }

  if (value instanceof Date && isNaN(value.getHours())) {
    return false;
  }

  if (typeof value === 'string') {
    return isValidDate(new Date(value));
  }

  return true;
}

export function toNumber(value: string | number): number {
  if (typeof value === 'number') {
    return value;
  }

  return parseInt(value, dex);
}

export function isNumber(value: string): boolean {
  return !isNaN(toNumber(value));
}

export function parseHours(value: string | number, isPM: boolean = false): number {
  const hour = toNumber(value);
  if (isNaN(hour) || hour < 0 || hour > (isPM ? hoursPerDayHalf : hoursPerDay)) {
    return NaN;
  }

  return hour;
}

export function parseMinutes(value: string | number): number {
  const minute = toNumber(value);
  if (isNaN(minute) || minute < 0 || minute > minutesPerHour) {
    return NaN;
  }

  return minute;
}

export function parseSeconds(value: string | number): number {
  const seconds = toNumber(value);
  if (isNaN(seconds) || seconds < 0 || seconds > secondsPerMinute) {
    return NaN;
  }

  return seconds;
}

export function parseTime(value: string | Date): Date {
  if (typeof value === 'string') {
    return new Date(value);
  }

  return value;
}

export function changeTime(value: Date, diff: Time): Date {
  if (!value) {
    return changeTime(createDate(new Date(),0,0, 0), diff);
  }

  let hour = value.getHours();
  let minutes = value.getMinutes();
  let seconds = value.getSeconds();

  if (diff.hour) {
    hour = (hour + toNumber(diff.hour)) % hoursPerDay;
    if (hour < 0) {
      hour += hoursPerDay;
    }
  }

  if (diff.minute) {
    minutes = (minutes + toNumber(diff.minute));
  }

  if (diff.seconds) {
    seconds = (seconds + toNumber(diff.seconds));
  }

  return createDate(value, hour, minutes, seconds);
}

export function setTime(value: Date, opts: Time): Date {
  let hour = parseHours(opts.hour);
  const minute = parseMinutes(opts.minute);
  const seconds = parseSeconds(opts.seconds) || 0;

  if (opts.isPM) {
    hour += hoursPerDayHalf;
  }

  // fixme: unreachable code, value is mandatory
  if (!value) {
    if (!isNaN(hour) && !isNaN(minute)) {
      return createDate(new Date(), hour, minute, seconds);
    }

    return value;
  }

  if (isNaN(hour) || isNaN(minute)) {
    return value;
  }

  return createDate(value, hour, minute, seconds);
}

export function createDate(value: Date, hours: number, minutes: number, seconds: number): Date {

  // fixme: unreachable code, value is mandatory
  const _value = value || new Date();
  return new Date(_value.getFullYear(), _value.getMonth(), _value.getDate(),
    hours, minutes, seconds, _value.getMilliseconds());
}

export function padNumber(value: number): string {
  const _value = value.toString();
  if (_value.length > 1) { return _value; }

  return `0${_value}`;
}

export function isInputValid(hours: string, minutes: string, seconds: string = '0', isPM: boolean): boolean {
  if (isNaN(parseHours(hours, isPM)) || isNaN(parseMinutes(minutes)) || isNaN(parseSeconds(seconds))) {
    return false;
  }
  return true;
}