/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 * Portions Copyright (C) Philipp Kewisch */

import RecurIterator from "./recur_iterator.js";
import Time from "./time.js";
import design from "./design.js";
import { strictParseInt, clone } from "./helpers.js";

/**
 * This lets typescript resolve our custom types in the
 * generated d.ts files (jsdoc typedefs are converted to typescript types).
 * Ignore prevents the typedefs from being documented more than once.
 *
 * @ignore
 * @typedef {import("./types.js").weekDay} weekDay
 * Imports the 'weekDay' type from the "types.js" module
 * @typedef {import("./types.js").frequencyValues} frequencyValues
 * Imports the 'frequencyValues' type from the "types.js" module
 */

const VALID_DAY_NAMES = /^(SU|MO|TU|WE|TH|FR|SA)$/;
const VALID_BYDAY_PART = /^([+-])?(5[0-3]|[1-4][0-9]|[1-9])?(SU|MO|TU|WE|TH|FR|SA)$/;
const DOW_MAP = {
  SU: Time.SUNDAY,
  MO: Time.MONDAY,
  TU: Time.TUESDAY,
  WE: Time.WEDNESDAY,
  TH: Time.THURSDAY,
  FR: Time.FRIDAY,
  SA: Time.SATURDAY
};

const REVERSE_DOW_MAP = Object.fromEntries(Object.entries(DOW_MAP).map(entry => entry.reverse()));

const ALLOWED_FREQ = ['SECONDLY', 'MINUTELY', 'HOURLY',
                      'DAILY', 'WEEKLY', 'MONTHLY', 'YEARLY'];

/**
 * This class represents the "recur" value type, used for example by RRULE. It provides methods to
 * calculate occurrences among others.
 *
 * @memberof ICAL
 */
class Recur {
  /**
   * Creates a new {@link ICAL.Recur} instance from the passed string.
   *
   * @param {String} string         The string to parse
   * @return {Recur}                The created recurrence instance
   */
  static fromString(string) {
    let data = this._stringToData(string, false);
    return new Recur(data);
  }

  /**
   * Creates a new {@link ICAL.Recur} instance using members from the passed
   * data object.
   *
   * @param {Object} aData                              An object with members of the recurrence
   * @param {frequencyValues=} aData.freq               The frequency value
   * @param {Number=} aData.interval                    The INTERVAL value
   * @param {weekDay=} aData.wkst                       The week start value
   * @param {Time=} aData.until                         The end of the recurrence set
   * @param {Number=} aData.count                       The number of occurrences
   * @param {Array.<Number>=} aData.bysecond            The seconds for the BYSECOND part
   * @param {Array.<Number>=} aData.byminute            The minutes for the BYMINUTE part
   * @param {Array.<Number>=} aData.byhour              The hours for the BYHOUR part
   * @param {Array.<String>=} aData.byday               The BYDAY values
   * @param {Array.<Number>=} aData.bymonthday          The days for the BYMONTHDAY part
   * @param {Array.<Number>=} aData.byyearday           The days for the BYYEARDAY part
   * @param {Array.<Number>=} aData.byweekno            The weeks for the BYWEEKNO part
   * @param {Array.<Number>=} aData.bymonth             The month for the BYMONTH part
   * @param {Array.<Number>=} aData.bysetpos            The positionals for the BYSETPOS part
   */
  static fromData(aData) {
    return new Recur(aData);
  }

  /**
   * Converts a recurrence string to a data object, suitable for the fromData
   * method.
   *
   * @private
   * @param {String} string     The string to parse
   * @param {Boolean} fmtIcal   If true, the string is considered to be an
   *                              iCalendar string
   * @return {Recur}            The recurrence instance
   */
  static _stringToData(string, fmtIcal) {
    let dict = Object.create(null);

    // split is slower in FF but fast enough.
    // v8 however this is faster then manual split?
    let values = string.split(';');
    let len = values.length;

    for (let i = 0; i < len; i++) {
      let parts = values[i].split('=');
      let ucname = parts[0].toUpperCase();
      let lcname = parts[0].toLowerCase();
      let name = (fmtIcal ? lcname : ucname);
      let value = parts[1];

      if (ucname in partDesign) {
        let partArr = value.split(',');
        let partSet = new Set();

        for (let part of partArr) {
          partSet.add(partDesign[ucname](part));
        }
        partArr = [...partSet];

        dict[name] = (partArr.length == 1 ? partArr[0] : partArr);
      } else if (ucname in optionDesign) {
        optionDesign[ucname](value, dict, fmtIcal);
      } else {
        // Don't swallow unknown values. Just set them as they are.
        dict[lcname] = value;
      }
    }

    return dict;
  }

  /**
   * Convert an ical representation of a day (SU, MO, etc..)
   * into a numeric value of that day.
   *
   * @param {String} string     The iCalendar day name
   * @param {weekDay=} aWeekStart
   *        The week start weekday, defaults to SUNDAY
   * @return {Number}           Numeric value of given day
   */
  static icalDayToNumericDay(string, aWeekStart) {
    //XXX: this is here so we can deal
    //     with possibly invalid string values.
    let firstDow = aWeekStart || Time.SUNDAY;
    return ((DOW_MAP[string] - firstDow + 7) % 7) + 1;
  }

  /**
   * Convert a numeric day value into its ical representation (SU, MO, etc..)
   *
   * @param {Number} num        Numeric value of given day
   * @param {weekDay=} aWeekStart
   *        The week start weekday, defaults to SUNDAY
   * @return {String}           The ICAL day value, e.g SU,MO,...
   */
  static numericDayToIcalDay(num, aWeekStart) {
    //XXX: this is here so we can deal with possibly invalid number values.
    //     Also, this allows consistent mapping between day numbers and day
    //     names for external users.
    let firstDow = aWeekStart || Time.SUNDAY;
    let dow = (num + firstDow - Time.SUNDAY);
    if (dow > 7) {
      dow -= 7;
    }
    return REVERSE_DOW_MAP[dow];
  }

  /**
   * Create a new instance of the Recur class.
   *
   * @param {Object} data                               An object with members of the recurrence
   * @param {frequencyValues=} data.freq                The frequency value
   * @param {Number=} data.interval                     The INTERVAL value
   * @param {weekDay=} data.wkst                        The week start value
   * @param {Time=} data.until                          The end of the recurrence set
   * @param {Number=} data.count                        The number of occurrences
   * @param {Array.<Number>=} data.bysecond             The seconds for the BYSECOND part
   * @param {Array.<Number>=} data.byminute             The minutes for the BYMINUTE part
   * @param {Array.<Number>=} data.byhour               The hours for the BYHOUR part
   * @param {Array.<String>=} data.byday                The BYDAY values
   * @param {Array.<Number>=} data.bymonthday           The days for the BYMONTHDAY part
   * @param {Array.<Number>=} data.byyearday            The days for the BYYEARDAY part
   * @param {Array.<Number>=} data.byweekno             The weeks for the BYWEEKNO part
   * @param {Array.<Number>=} data.bymonth              The month for the BYMONTH part
   * @param {Array.<Number>=} data.bysetpos             The positionals for the BYSETPOS part
   */
  constructor(data) {
    this.wrappedJSObject = this;
    this.parts = {};

    if (data && typeof(data) === 'object') {
      this.fromData(data);
    }
  }

  /**
   * An object holding the BY-parts of the recurrence rule
   * @memberof ICAL.Recur
   * @typedef {Object} byParts
   * @property {Array.<Number>=} BYSECOND            The seconds for the BYSECOND part
   * @property {Array.<Number>=} BYMINUTE            The minutes for the BYMINUTE part
   * @property {Array.<Number>=} BYHOUR              The hours for the BYHOUR part
   * @property {Array.<String>=} BYDAY               The BYDAY values
   * @property {Array.<Number>=} BYMONTHDAY          The days for the BYMONTHDAY part
   * @property {Array.<Number>=} BYYEARDAY           The days for the BYYEARDAY part
   * @property {Array.<Number>=} BYWEEKNO            The weeks for the BYWEEKNO part
   * @property {Array.<Number>=} BYMONTH             The month for the BYMONTH part
   * @property {Array.<Number>=} BYSETPOS            The positionals for the BYSETPOS part
   */

  /**
   * An object holding the BY-parts of the recurrence rule
   * @type {byParts}
   */
  parts = null;

  /**
   * The interval value for the recurrence rule.
   * @type {Number}
   */
  interval = 1;

  /**
   * The week start day
   *
   * @type {weekDay}
   * @default ICAL.Time.MONDAY
   */
  wkst = Time.MONDAY;

  /**
   * The end of the recurrence
   * @type {?Time}
   */
  until = null;

  /**
   * The maximum number of occurrences
   * @type {?Number}
   */
  count = null;

  /**
   * The frequency value.
   * @type {frequencyValues}
   */
  freq = null;

  /**
   * The class identifier.
   * @constant
   * @type {String}
   * @default "icalrecur"
   */
  icalclass = "icalrecur";

  /**
   * The type name, to be used in the jCal object.
   * @constant
   * @type {String}
   * @default "recur"
   */
  icaltype = "recur";

  /**
   * Create a new iterator for this recurrence rule. The passed start date
   * must be the start date of the event, not the start of the range to
   * search in.
   *
   * @example
   * let recur = comp.getFirstPropertyValue('rrule');
   * let dtstart = comp.getFirstPropertyValue('dtstart');
   * let iter = recur.iterator(dtstart);
   * for (let next = iter.next(); next; next = iter.next()) {
   *   if (next.compare(rangeStart) < 0) {
   *     continue;
   *   }
   *   console.log(next.toString());
   * }
   *
   * @param {Time} aStart        The item's start date
   * @return {RecurIterator}     The recurrence iterator
   */
  iterator(aStart) {
    return new RecurIterator({
      rule: this,
      dtstart: aStart
    });
  }

  /**
   * Returns a clone of the recurrence object.
   *
   * @return {Recur}      The cloned object
   */
  clone() {
    return new Recur(this.toJSON());
  }

  /**
   * Checks if the current rule is finite, i.e. has a count or until part.
   *
   * @return {Boolean}        True, if the rule is finite
   */
  isFinite() {
    return !!(this.count || this.until);
  }

  /**
   * Checks if the current rule has a count part, and not limited by an until
   * part.
   *
   * @return {Boolean}        True, if the rule is by count
   */
  isByCount() {
    return !!(this.count && !this.until);
  }

  /**
   * Adds a component (part) to the recurrence rule. This is not a component
   * in the sense of {@link ICAL.Component}, but a part of the recurrence
   * rule, i.e. BYMONTH.
   *
   * @param {String} aType            The name of the component part
   * @param {Array|String} aValue     The component value
   */
  addComponent(aType, aValue) {
    let ucname = aType.toUpperCase();
    if (ucname in this.parts) {
      this.parts[ucname].push(aValue);
    } else {
      this.parts[ucname] = [aValue];
    }
  }

  /**
   * Sets the component value for the given by-part.
   *
   * @param {String} aType        The component part name
   * @param {Array} aValues       The component values
   */
  setComponent(aType, aValues) {
    this.parts[aType.toUpperCase()] = aValues.slice();
  }

  /**
   * Gets (a copy) of the requested component value.
   *
   * @param {String} aType        The component part name
   * @return {Array}              The component part value
   */
  getComponent(aType) {
    let ucname = aType.toUpperCase();
    return (ucname in this.parts ? this.parts[ucname].slice() : []);
  }

  /**
   * Retrieves the next occurrence after the given recurrence id. See the
   * guide on {@tutorial terminology} for more details.
   *
   * NOTE: Currently, this method iterates all occurrences from the start
   * date. It should not be called in a loop for performance reasons. If you
   * would like to get more than one occurrence, you can iterate the
   * occurrences manually, see the example on the
   * {@link ICAL.Recur#iterator iterator} method.
   *
   * @param {Time} aStartTime        The start of the event series
   * @param {Time} aRecurrenceId     The date of the last occurrence
   * @return {Time}                  The next occurrence after
   */
  getNextOccurrence(aStartTime, aRecurrenceId) {
    let iter = this.iterator(aStartTime);
    let next;

    do {
      next = iter.next();
    } while (next && next.compare(aRecurrenceId) <= 0);

    if (next && aRecurrenceId.zone) {
      next.zone = aRecurrenceId.zone;
    }

    return next;
  }

  /**
   * Sets up the current instance using members from the passed data object.
   *
   * @param {Object} data                               An object with members of the recurrence
   * @param {frequencyValues=} data.freq                The frequency value
   * @param {Number=} data.interval                     The INTERVAL value
   * @param {weekDay=} data.wkst                        The week start value
   * @param {Time=} data.until                          The end of the recurrence set
   * @param {Number=} data.count                        The number of occurrences
   * @param {Array.<Number>=} data.bysecond             The seconds for the BYSECOND part
   * @param {Array.<Number>=} data.byminute             The minutes for the BYMINUTE part
   * @param {Array.<Number>=} data.byhour               The hours for the BYHOUR part
   * @param {Array.<String>=} data.byday                The BYDAY values
   * @param {Array.<Number>=} data.bymonthday           The days for the BYMONTHDAY part
   * @param {Array.<Number>=} data.byyearday            The days for the BYYEARDAY part
   * @param {Array.<Number>=} data.byweekno             The weeks for the BYWEEKNO part
   * @param {Array.<Number>=} data.bymonth              The month for the BYMONTH part
   * @param {Array.<Number>=} data.bysetpos             The positionals for the BYSETPOS part
   */
  fromData(data) {
    for (let key in data) {
      let uckey = key.toUpperCase();

      if (uckey in partDesign) {
        if (Array.isArray(data[key])) {
          this.parts[uckey] = data[key];
        } else {
          this.parts[uckey] = [data[key]];
        }
      } else {
        this[key] = data[key];
      }
    }

    if (this.interval && typeof this.interval != "number") {
      optionDesign.INTERVAL(this.interval, this);
    }

    if (this.wkst && typeof this.wkst != "number") {
      this.wkst = Recur.icalDayToNumericDay(this.wkst);
    }

    if (this.until && !(this.until instanceof Time)) {
      this.until = Time.fromString(this.until);
    }
  }

  /**
   * The jCal representation of this recurrence type.
   * @return {Object}
   */
  toJSON() {
    let res = Object.create(null);
    res.freq = this.freq;

    if (this.count) {
      res.count = this.count;
    }

    if (this.interval > 1) {
      res.interval = this.interval;
    }

    for (let [k, kparts] of Object.entries(this.parts)) {
      if (Array.isArray(kparts) && kparts.length == 1) {
        res[k.toLowerCase()] = kparts[0];
      } else {
        res[k.toLowerCase()] = clone(kparts);
      }
    }

    if (this.until) {
      res.until = this.until.toString();
    }
    if ('wkst' in this && this.wkst !== Time.DEFAULT_WEEK_START) {
      res.wkst = Recur.numericDayToIcalDay(this.wkst);
    }
    return res;
  }

  /**
   * The string representation of this recurrence rule.
   * @return {String}
   */
  toString() {
    // TODO retain order
    let str = "FREQ=" + this.freq;
    if (this.count) {
      str += ";COUNT=" + this.count;
    }
    if (this.interval > 1) {
      str += ";INTERVAL=" + this.interval;
    }
    for (let [k, v] of Object.entries(this.parts)) {
      str += ";" + k + "=" + v;
    }
    if (this.until) {
      str += ';UNTIL=' + this.until.toICALString();
    }
    if ('wkst' in this && this.wkst !== Time.DEFAULT_WEEK_START) {
      str += ';WKST=' + Recur.numericDayToIcalDay(this.wkst);
    }
    return str;
  }
}
export default Recur;

function parseNumericValue(type, min, max, value) {
  let result = value;

  if (value[0] === '+') {
    result = value.slice(1);
  }

  result = strictParseInt(result);

  if (min !== undefined && value < min) {
    throw new Error(
      type + ': invalid value "' + value + '" must be > ' + min
    );
  }

  if (max !== undefined && value > max) {
    throw new Error(
      type + ': invalid value "' + value + '" must be < ' + min
    );
  }

  return result;
}

const optionDesign = {
  FREQ: function(value, dict, fmtIcal) {
    // yes this is actually equal or faster then regex.
    // upside here is we can enumerate the valid values.
    if (ALLOWED_FREQ.indexOf(value) !== -1) {
      dict.freq = value;
    } else {
      throw new Error(
        'invalid frequency "' + value + '" expected: "' +
        ALLOWED_FREQ.join(', ') + '"'
      );
    }
  },

  COUNT: function(value, dict, fmtIcal) {
    dict.count = strictParseInt(value);
  },

  INTERVAL: function(value, dict, fmtIcal) {
    dict.interval = strictParseInt(value);
    if (dict.interval < 1) {
      // 0 or negative values are not allowed, some engines seem to generate
      // it though. Assume 1 instead.
      dict.interval = 1;
    }
  },

  UNTIL: function(value, dict, fmtIcal) {
    if (value.length > 10) {
      dict.until = design.icalendar.value['date-time'].fromICAL(value);
    } else {
      dict.until = design.icalendar.value.date.fromICAL(value);
    }
    if (!fmtIcal) {
      dict.until = Time.fromString(dict.until);
    }
  },

  WKST: function(value, dict, fmtIcal) {
    if (VALID_DAY_NAMES.test(value)) {
      dict.wkst = Recur.icalDayToNumericDay(value);
    } else {
      throw new Error('invalid WKST value "' + value + '"');
    }
  }
};

const partDesign = {
  BYSECOND: parseNumericValue.bind(undefined, 'BYSECOND', 0, 60),
  BYMINUTE: parseNumericValue.bind(undefined, 'BYMINUTE', 0, 59),
  BYHOUR: parseNumericValue.bind(undefined, 'BYHOUR', 0, 23),
  BYDAY: function(value) {
    if (VALID_BYDAY_PART.test(value)) {
      return value;
    } else {
      throw new Error('invalid BYDAY value "' + value + '"');
    }
  },
  BYMONTHDAY: parseNumericValue.bind(undefined, 'BYMONTHDAY', -31, 31),
  BYYEARDAY: parseNumericValue.bind(undefined, 'BYYEARDAY', -366, 366),
  BYWEEKNO: parseNumericValue.bind(undefined, 'BYWEEKNO', -53, 53),
  BYMONTH: parseNumericValue.bind(undefined, 'BYMONTH', 1, 12),
  BYSETPOS: parseNumericValue.bind(undefined, 'BYSETPOS', -366, 366)
};