import { getHours, getMinutes, getSeconds } from '../utils/date-getters';
import { addFormatToken } from '../format/format';
import { zeroFill } from '../utils/zero-fill';
import { Locale } from '../locale/locale.class';
import { addRegexToken, match1to2, match2, match3to4, match5to6 } from '../parse/regex';
import { addParseToken } from '../parse/token';
import { HOUR, MINUTE, SECOND } from './constants';
import { toInt } from '../utils/type-checks';
import { DateArray, DateFormatterOptions } from '../types';
import { DateParsingConfig } from '../create/parsing.types';
import { getParsingFlags } from '../create/parsing-flags';
import { addUnitPriority } from './priorities';
import { addUnitAlias } from './aliases';

// FORMATTING

function hFormat(date: Date, isUTC: boolean): number {
  return getHours(date, isUTC) % 12 || 12;
}

function kFormat(date: Date, isUTC: boolean): number {
  return getHours(date, isUTC) || 24;
}

addFormatToken('H', ['HH', 2, false], null,
  function (date: Date, opts: DateFormatterOptions): string {
    return getHours(date, opts.isUTC).toString(10);
  });
addFormatToken('h', ['hh', 2, false], null,
  function (date: Date, opts: DateFormatterOptions): string {
    return hFormat(date, opts.isUTC).toString(10);
  });
addFormatToken('k', ['kk', 2, false], null,
  function (date: Date, opts: DateFormatterOptions): string {
    return kFormat(date, opts.isUTC).toString(10);
  });

addFormatToken('hmm', null, null,
  function (date: Date, opts: DateFormatterOptions): string {
    const _h = hFormat(date, opts.isUTC);
    const _mm = zeroFill(getMinutes(date, opts.isUTC), 2);

    return `${_h}${_mm}`;
  });

addFormatToken('hmmss', null, null,
  function (date: Date, opts: DateFormatterOptions): string {
    const _h = hFormat(date, opts.isUTC);
    const _mm = zeroFill(getMinutes(date, opts.isUTC), 2);
    const _ss = zeroFill(getSeconds(date, opts.isUTC), 2);

    return `${_h}${_mm}${_ss}`;
  });

addFormatToken('Hmm', null, null,
  function (date: Date, opts: DateFormatterOptions): string {
    const _H = getHours(date, opts.isUTC);
    const _mm = zeroFill(getMinutes(date, opts.isUTC), 2);

    return `${_H}${_mm}`;
  });

addFormatToken('Hmmss', null, null,
  function (date: Date, opts: DateFormatterOptions): string {
    const _H = getHours(date, opts.isUTC);
    const _mm = zeroFill(getMinutes(date, opts.isUTC), 2);
    const _ss = zeroFill(getSeconds(date, opts.isUTC), 2);

    return `${_H}${_mm}${_ss}`;
  });

function meridiem(token: string, lowercase: boolean): void {
  addFormatToken(token, null, null,
    function (date: Date, opts: DateFormatterOptions): string {
      return opts.locale.meridiem(getHours(date, opts.isUTC), getMinutes(date, opts.isUTC), lowercase);
    });
}

meridiem('a', true);
meridiem('A', false);

// ALIASES

addUnitAlias('hour', 'h');

// PRIORITY
addUnitPriority('hour', 13);


// PARSING

function matchMeridiem(isStrict: boolean, locale: Locale): RegExp {
  return locale._meridiemParse;
}

addRegexToken('a', matchMeridiem);
addRegexToken('A', matchMeridiem);
addRegexToken('H', match1to2);
addRegexToken('h', match1to2);
addRegexToken('k', match1to2);
addRegexToken('HH', match1to2, match2);
addRegexToken('hh', match1to2, match2);
addRegexToken('kk', match1to2, match2);

addRegexToken('hmm', match3to4);
addRegexToken('hmmss', match5to6);
addRegexToken('Hmm', match3to4);
addRegexToken('Hmmss', match5to6);

addParseToken(['H', 'HH'], HOUR);
addParseToken(['k', 'kk'],
  function (input: string, array: DateArray, config: DateParsingConfig): DateParsingConfig {
    const kInput = toInt(input);
    array[HOUR] = kInput === 24 ? 0 : kInput;

    return config;
  });
addParseToken(['a', 'A'], function (input: string, array: DateArray, config: DateParsingConfig): DateParsingConfig {
  config._isPm = config._locale.isPM(input);
  config._meridiem = input;

  return config;
});
addParseToken(['h', 'hh'], function (input: string, array: DateArray, config: DateParsingConfig): DateParsingConfig {
  array[HOUR] = toInt(input);
  getParsingFlags(config).bigHour = true;

  return config;
});
addParseToken('hmm', function (input: string, array: DateArray, config: DateParsingConfig): DateParsingConfig {
  const pos = input.length - 2;
  array[HOUR] = toInt(input.substr(0, pos));
  array[MINUTE] = toInt(input.substr(pos));
  getParsingFlags(config).bigHour = true;

  return config;
});
addParseToken('hmmss', function (input: string, array: DateArray, config: DateParsingConfig): DateParsingConfig {
  const pos1 = input.length - 4;
  const pos2 = input.length - 2;
  array[HOUR] = toInt(input.substr(0, pos1));
  array[MINUTE] = toInt(input.substr(pos1, 2));
  array[SECOND] = toInt(input.substr(pos2));
  getParsingFlags(config).bigHour = true;

  return config;
});
addParseToken('Hmm', function (input: string, array: DateArray, config: DateParsingConfig): DateParsingConfig {
  const pos = input.length - 2;
  array[HOUR] = toInt(input.substr(0, pos));
  array[MINUTE] = toInt(input.substr(pos));

  return config;
});
addParseToken('Hmmss', function (input: string, array: DateArray, config: DateParsingConfig): DateParsingConfig {
  const pos1 = input.length - 4;
  const pos2 = input.length - 2;
  array[HOUR] = toInt(input.substr(0, pos1));
  array[MINUTE] = toInt(input.substr(pos1, 2));
  array[SECOND] = toInt(input.substr(pos2));

  return config;
});