<template>
  <transition name="el-zoom-in-top" @after-leave="$emit('dodestroy')">
    <div
      v-show="visible"
      class="el-time-panel el-popper"
      :class="popperClass">
      <div class="el-time-panel__content" :class="{ 'has-seconds': showSeconds }">
        <time-spinner
          ref="spinner"
          @change="handleChange"
          :arrow-control="useArrow"
          :show-seconds="showSeconds"
          @select-range="setSelectionRange"
          :date="date">
        </time-spinner>
      </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"
          :class="{confirm: !disabled}"
          @click="handleConfirm()">{{ t('el.datepicker.confirm') }}</button>
      </div>
    </div>
  </transition>
</template>

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

  export default {
    mixins: [Locale],

    components: {
      TimeSpinner
    },

    props: {
      visible: Boolean,
      timeArrowControl: Boolean
    },

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

      value(newVal) {
        let date;
        if (newVal instanceof Date) {
          date = limitTimeRange(newVal, this.selectableRange, this.format);
        } else if (!newVal) {
          date = this.defaultValue ? new Date(this.defaultValue) : new Date();
        }

        this.date = date;
        if (this.visible) {
          this.$nextTick(_ => this.adjustSpinners());
        }
      },

      selectableRange(val) {
        this.$refs.spinner.selectableRange = val;
      },

      defaultValue(val) {
        if (!isDate(this.value)) {
          this.date = val ? new Date(val) : new Date();
        }
      }
    },

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

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

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

      handleChange(date) {
        // this.visible avoids edge cases, when use scrolls during panel closing animation
        if (this.visible) {
          this.date = clearMilliseconds(date);
          // if date is out of range, do not emit
          if (this.isValidValue(this.date)) {
            this.$emit('pick', this.date, true);
          }
        }
      },

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

      handleConfirm(visible = false, first) {
        if (first) return;
        const date = clearMilliseconds(limitTimeRange(this.date, this.selectableRange, this.format));
        this.$emit('pick', date, visible, first);
      },

      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.$refs.spinner.scrollDown(step);
          event.preventDefault();
          return;
        }
      },

      isValidValue(date) {
        return timeWithinRange(date, this.selectableRange, this.format);
      },

      adjustSpinners() {
        return this.$refs.spinner.adjustSpinners();
      },

      changeSelectionRange(step) {
        const list = [0, 3].concat(this.showSeconds ? [6] : []);
        const mapping = ['hours', 'minutes'].concat(this.showSeconds ? ['seconds'] : []);
        const index = list.indexOf(this.selectionRange[0]);
        const next = (index + step + list.length) % list.length;
        this.$refs.spinner.emitSelectRange(mapping[next]);
      }
    },

    mounted() {
      this.$nextTick(() => this.handleConfirm(true, true));
      this.$emit('mounted');
    }
  };
</script>
