<template>
  <transition name="el-zoom-in-top" @after-leave="$emit('dodestroy')">
    <div v-show="visible" class="el-time-range-picker el-picker-panel el-popper" :class="popperClass">
      <div class="el-time-range-picker__content">
        <div class="el-time-range-picker__cell">
          <div class="el-time-range-picker__header">{{ t('el.datepicker.startTime') }}</div>
          <div
            :class="{ 'has-seconds': showSeconds, 'is-arrow': arrowControl }"
            class="el-time-range-picker__body el-time-panel__content"
          >
            <time-spinner
              ref="minSpinner"
              :show-seconds="showSeconds"
              :am-pm-mode="amPmMode"
              @change="handleMinChange"
              :arrow-control="arrowControl"
              @select-range="setMinSelectionRange"
              :date="minDate"
            ></time-spinner>
          </div>
        </div>
        <div class="el-time-range-picker__cell">
          <div class="el-time-range-picker__header">{{ t('el.datepicker.endTime') }}</div>
          <div
            :class="{ 'has-seconds': showSeconds, 'is-arrow': arrowControl }"
            class="el-time-range-picker__body el-time-panel__content"
          >
            <time-spinner
              ref="maxSpinner"
              :show-seconds="showSeconds"
              :am-pm-mode="amPmMode"
              @change="handleMaxChange"
              :arrow-control="arrowControl"
              @select-range="setMaxSelectionRange"
              :date="maxDate"
            ></time-spinner>
          </div>
        </div>
      </div>
      <div class="el-time-panel__footer">
        <button type="button" class="el-time-panel__btn cancel" @click="handleCancel()">
          {{ t('el.datepicker.cancel') }}
        </button>
        <button type="button" class="el-time-panel__btn confirm" @click="handleConfirm()" :disabled="btnDisabled">
          {{ t('el.datepicker.confirm') }}
        </button>
      </div>
    </div>
  </transition>
</template>

<script type="text/babel">
import {
  parseDate,
  limitTimeRange,
  modifyDate,
  clearMilliseconds,
  timeWithinRange
} from 'capsule-ui/src/utils/date-util';
import Locale from 'capsule-ui/src/mixins/locale';
import TimeSpinner from '../basic/time-spinner';

const MIN_TIME = parseDate('00:00:00', 'HH:mm:ss');
const MAX_TIME = parseDate('23:59:59', 'HH:mm:ss');

const minTimeOfDay = function(date) {
  return modifyDate(MIN_TIME, date.getFullYear(), date.getMonth(), date.getDate());
};

const maxTimeOfDay = function(date) {
  return modifyDate(MAX_TIME, date.getFullYear(), date.getMonth(), date.getDate());
};

// increase time by amount of milliseconds, but within the range of day
const advanceTime = function(date, amount) {
  return new Date(Math.min(date.getTime() + amount, maxTimeOfDay(date).getTime()));
};

export default {
  mixins: [Locale],

  components: { TimeSpinner },

  computed: {
    showSeconds() {
      return (this.format || '').indexOf('ss') !== -1;
    },

    offset() {
      return this.showSeconds ? 11 : 8;
    },

    spinner() {
      return this.selectionRange[0] < this.offset ? this.$refs.minSpinner : this.$refs.maxSpinner;
    },

    btnDisabled() {
      return this.minDate.getTime() > this.maxDate.getTime();
    },
    amPmMode() {
      if ((this.format || '').indexOf('A') !== -1) return 'A';
      if ((this.format || '').indexOf('a') !== -1) return 'a';
      return '';
    }
  },

  data() {
    return {
      popperClass: '',
      minDate: new Date(),
      maxDate: new Date(),
      value: [],
      oldValue: [new Date(), new Date()],
      defaultValue: null,
      format: 'HH:mm:ss',
      visible: false,
      selectionRange: [0, 2],
      arrowControl: false
    };
  },

  watch: {
    value(value) {
      if (Array.isArray(value)) {
        this.minDate = new Date(value[0]);
        this.maxDate = new Date(value[1]);
      } else {
        if (Array.isArray(this.defaultValue)) {
          this.minDate = new Date(this.defaultValue[0]);
          this.maxDate = new Date(this.defaultValue[1]);
        } else if (this.defaultValue) {
          this.minDate = new Date(this.defaultValue);
          this.maxDate = advanceTime(new Date(this.defaultValue), 60 * 60 * 1000);
        } else {
          this.minDate = new Date();
          this.maxDate = advanceTime(new Date(), 60 * 60 * 1000);
        }
      }
    },

    visible(val) {
      if (val) {
        this.oldValue = this.value;
        this.$nextTick(() => this.$refs.minSpinner.emitSelectRange('hours'));
      }
    }
  },

  methods: {
    handleClear() {
      this.$emit('pick', null);
    },

    handleCancel() {
      this.$emit('pick', this.oldValue);
    },

    handleMinChange(date) {
      this.minDate = clearMilliseconds(date);
      this.handleChange();
    },

    handleMaxChange(date) {
      this.maxDate = clearMilliseconds(date);
      this.handleChange();
    },

    handleChange() {
      if (this.isValidValue([this.minDate, this.maxDate])) {
        this.$refs.minSpinner.selectableRange = [[minTimeOfDay(this.minDate), this.maxDate]];
        this.$refs.maxSpinner.selectableRange = [[this.minDate, maxTimeOfDay(this.maxDate)]];
        this.$emit('pick', [this.minDate, this.maxDate], true);
      }
    },

    setMinSelectionRange(start, end) {
      this.$emit('select-range', start, end, 'min');
      this.selectionRange = [start, end];
    },

    setMaxSelectionRange(start, end) {
      this.$emit('select-range', start, end, 'max');
      this.selectionRange = [start + this.offset, end + this.offset];
    },

    handleConfirm(visible = false) {
      const minSelectableRange = this.$refs.minSpinner.selectableRange;
      const maxSelectableRange = this.$refs.maxSpinner.selectableRange;

      this.minDate = limitTimeRange(this.minDate, minSelectableRange, this.format);
      this.maxDate = limitTimeRange(this.maxDate, maxSelectableRange, this.format);

      this.$emit('pick', [this.minDate, this.maxDate], visible);
    },

    adjustSpinners() {
      this.$refs.minSpinner.adjustSpinners();
      this.$refs.maxSpinner.adjustSpinners();
    },

    changeSelectionRange(step) {
      const list = this.showSeconds ? [0, 3, 6, 11, 14, 17] : [0, 3, 8, 11];
      const mapping = ['hours', 'minutes'].concat(this.showSeconds ? ['seconds'] : []);
      const index = list.indexOf(this.selectionRange[0]);
      const next = (index + step + list.length) % list.length;
      const half = list.length / 2;
      if (next < half) {
        this.$refs.minSpinner.emitSelectRange(mapping[next]);
      } else {
        this.$refs.maxSpinner.emitSelectRange(mapping[next - half]);
      }
    },

    isValidValue(date) {
      return (
        Array.isArray(date) &&
        timeWithinRange(this.minDate, this.$refs.minSpinner.selectableRange) &&
        timeWithinRange(this.maxDate, this.$refs.maxSpinner.selectableRange)
      );
    },

    handleKeydown(event) {
      const keyCode = event.keyCode;
      const mapping = { 38: -1, 40: 1, 37: -1, 39: 1 };

      // Left or Right
      if (keyCode === 37 || keyCode === 39) {
        const step = mapping[keyCode];
        this.changeSelectionRange(step);
        event.preventDefault();
        return;
      }

      // Up or Down
      if (keyCode === 38 || keyCode === 40) {
        const step = mapping[keyCode];
        this.spinner.scrollDown(step);
        event.preventDefault();
        return;
      }
    }
  }
};
</script>
