<template>
  <div
    @dragstart.prevent
    :class="[
      'el-input-number',
      inputNumberSize ? 'el-input-number--' + inputNumberSize : '',
      { 'is-disabled': inputNumberDisabled },
      { 'is-without-controls': !controls },
      { 'is-controls-right': controlsAtRight },
    ]"
  >
    <span
      class="el-input-number__decrease"
      role="button"
      v-if="controls"
      v-repeat-click="decrease"
      :class="{ 'is-disabled': minDisabled || inputNumberDisabled }"
      @keydown.enter="decrease"
    >
      <i :class="`el-icon-${controlsAtRight ? 'arrow-down' : 'minus'}`"></i>
    </span>
    <span
      class="el-input-number__increase"
      role="button"
      v-if="controls"
      v-repeat-click="increase"
      :class="{ 'is-disabled': maxDisabled || inputNumberDisabled }"
      @keydown.enter="increase"
    >
      <i :class="`el-icon-${controlsAtRight ? 'arrow-up' : 'plus'}`"></i>
    </span>
    <el-input
      ref="input"
      :class="[getContentAlign]"
      :value="currentValue"
      :disabled="inputNumberDisabled"
      :size="inputNumberSize"
      :max="max"
      :min="min"
      :name="name"
      :label="label"
      @keydown.up.native.prevent="increase"
      @keydown.down.native.prevent="decrease"
      @blur="handleBlur"
      @focus="handleFocus"
      @input="handleInputValue"
      @change="handleInputChange"
    >
      <template slot="prepend" v-if="$slots.prepend">
        <slot name="prepend"></slot>
      </template>
      <template slot="append" v-if="$slots.append">
        <slot name="append"></slot>
      </template>
    </el-input>
  </div>
</template>
<script>
import ElInput from 'kyligence-kylin-ui/packages/input';
import Focus from 'kyligence-kylin-ui/src/mixins/focus';
import RepeatClick from 'kyligence-kylin-ui/src/directives/repeat-click';

export default {
  name: 'ElInputNumber',
  mixins: [Focus('input')],
  inject: {
    elForm: {
      default: ''
    },
    elFormItem: {
      default: ''
    }
  },
  directives: {
    repeatClick: RepeatClick
  },
  components: {
    ElInput
  },
  props: {
    step: {
      type: Number,
      default: 1
    },
    max: {
      type: Number,
      default: Infinity
    },
    min: {
      type: Number,
      default: -Infinity
    },
    value: {},
    disabled: Boolean,
    size: {
      type: String,
      default: 'medium'
    },
    controls: {
      type: Boolean,
      default: true
    },
    controlsPosition: {
      type: String,
      default: ''
    },
    name: String,
    label: String,
    inputEnabled: Boolean,
    contentAlign: String
  },
  data() {
    return {
      currentValue: 0
    };
  },
  watch: {
    value: {
      immediate: true,
      handler(value) {
        let newVal = value === undefined ? value : Number(value);
        if (newVal !== undefined && isNaN(newVal)) return;
        if (newVal >= this.max) newVal = this.max;
        if (newVal <= this.min) newVal = this.min;
        this.currentValue = newVal;
        this.$emit('input', newVal);
      }
    }
  },
  computed: {
    minDisabled() {
      return this._decrease(this.value, this.step) < this.min;
    },
    maxDisabled() {
      return this._increase(this.value, this.step) > this.max;
    },
    precision() {
      const { value, step, getPrecision } = this;
      return Math.max(getPrecision(value), getPrecision(step));
    },
    controlsAtRight() {
      return this.controlsPosition === 'right';
    },
    _elFormItemSize() {
      return (this.elFormItem || {}).elFormItemSize;
    },
    inputNumberSize() {
      return (
        this.size ||
        this._elFormItemSize ||
        (this.$KY_ELEMENT['ElInputNumber'] || {}).size ||
        (this.$ELEMENT || {}).size
      );
    },
    inputNumberDisabled() {
      return this.disabled || (this.elForm || {}).disabled;
    },
    getContentAlign() {
      if (!this.contentAlign) return '';
      if (this.contentAlign === 'left') return 'text-left';
      if (this.contentAlign === 'left') return 'text-right';
      return '';
    }
  },
  methods: {
    toPrecision(num, precision) {
      if (precision === undefined) precision = this.precision;
      return parseFloat(parseFloat(Number(num).toFixed(precision)));
    },
    getPrecision(value) {
      if (value === undefined) return 0;
      const valueString = value.toString();
      const dotPosition = valueString.indexOf('.');
      let precision = 0;
      if (dotPosition !== -1) {
        precision = valueString.length - dotPosition - 1;
      }
      return precision;
    },
    _increase(val, step) {
      if (typeof val !== 'number' && val !== undefined) {return this.currentValue;}

      const precisionFactor = Math.pow(10, this.precision);
      // Solve the accuracy problem of JS decimal calculation by converting the value to integer.
      return this.toPrecision(
        (precisionFactor * val + precisionFactor * step) / precisionFactor
      );
    },
    _decrease(val, step) {
      if (typeof val !== 'number' && val !== undefined) {return this.currentValue;}

      const precisionFactor = Math.pow(10, this.precision);

      return this.toPrecision(
        (precisionFactor * val - precisionFactor * step) / precisionFactor
      );
    },
    increase() {
      if (this.inputNumberDisabled || this.maxDisabled) return;
      const value = this.value || 0;
      const newVal = this._increase(value, this.step);
      this.setCurrentValue(newVal);
    },
    decrease() {
      if (this.inputNumberDisabled || this.minDisabled) return;
      const value = this.value || 0;
      const newVal = this._decrease(value, this.step);
      this.setCurrentValue(newVal);
    },
    handleBlur(event) {
      this.$emit('blur', event);
      this.$refs.input.setCurrentValue(this.currentValue);
    },
    handleFocus(event) {
      this.$emit('focus', event);
    },
    handleInputValue(v) {
      if (!this.inputEnabled) return;
      this.handleInputChange(v);
    },
    setCurrentValue(newVal) {
      const oldVal = this.currentValue;
      if (newVal >= this.max) newVal = this.max;
      if (newVal <= this.min) newVal = this.min;
      if (oldVal === newVal) {
        this.$refs.input.setCurrentValue(this.currentValue);
        return;
      }
      this.$emit('change', newVal, oldVal);
      this.$emit('input', newVal);
      this.currentValue = newVal;
    },
    handleInputChange(value) {
      const newVal = value === '' ? undefined : Number(value);
      if (!isNaN(newVal) || value === '') {
        this.setCurrentValue(newVal);
      }
    }
  },
  mounted() {
    let innerInput = this.$refs.input.$refs.input;
    innerInput.setAttribute('role', 'spinbutton');
    innerInput.setAttribute('aria-valuemax', this.max);
    innerInput.setAttribute('aria-valuemin', this.min);
    innerInput.setAttribute('aria-valuenow', this.currentValue);
    innerInput.setAttribute('aria-disabled', this.inputNumberDisabled);
  },
  updated() {
    let innerInput = this.$refs.input.$refs.input;
    innerInput.setAttribute('aria-valuenow', this.currentValue);
  }
};
</script>
