<template>
  <view class="nana-form-picker">
    <slot v-if="loaded && (columns.length === 0 || (columns.length === 1 && columns[0].length === 0))" name="empty">
      <Empty description="暂无可选数据" :innerStyle="{ position: 'absolute', width: '100%' }" />
    </slot>
    <picker-view 
      v-else-if="loaded"
      :value="pickerSelectIndex" 
      class="picker-view"
      :style="{
        width: themeContext.resolveThemeSize(pickerWidth),
        height: themeContext.resolveThemeSize(pickerHeight),
      }"
      immediate-change
      @change="bindChange" 
    >
      <picker-view-column v-for="(column,c) in columns" :key="c">
        <view class="item" v-for="(item,k) in column" :key="k">{{item.text}}</view>
      </picker-view-column>
    </picker-view>
  </view>
</template>

<script setup lang="ts">
import { nextTick, onMounted, ref, watch } from 'vue';
import { useTheme } from '../theme/ThemeDefine';
import Empty from '../feedback/Empty.vue';

const themeContext = useTheme();

export interface PickerItem {
  text: string;
  value: string|number;
}

export interface PickerProps {
  /**
   * 选择器列
   */
  columns: PickerItem[][];
  /**
   * 选中Value
   */
  value: (number|string)[],
  /**
   * picker高度
   * @default 300
   */
  pickerHeight?: string|number,
  /**
   * picker宽度
   * @default 750
   */
  pickerWidth?: string|number,
  /**
   * 是否在columns只有一列情况下value返回一个值
   * @default false
   */
  singleValue?: boolean,
}

const emit = defineEmits([ 'update:value', 'selectTextChange' ]);
const props = withDefaults(defineProps<PickerProps>(), {
  pickerHeight: 300,
  pickerWidth: 750,
});

const loaded = ref(false);
const pickerSelectIndex = ref<number[]>([]);

function bindChange(e: any) {
  const val = e.detail.value as number[];
  for (let i = 0; i < props.columns.length; i++) 
    if (val[i] === undefined)
      val[i] = 0;

  const value = val.map((p, i) => {
    const cols = props.columns[i];
    if (!cols || cols.length === 0) 
      return null;
    return cols[p].value ?? cols[0].value ?? null;
  });
  pickerSelectIndex.value = val;


  if (props.singleValue && props.columns.length === 1)
    emit('update:value', value[0]);
  else 
    emit('update:value', value);
  emit('selectTextChange', val.map((p, i) => {
    const cols = props.columns[i];
    if (!cols || cols.length === 0) 
      return null;
    return cols[p].text ?? cols[0].text ?? null;
  }).join(' '));
}
function loadValues() {
  const value = typeof props.value === 'number' || typeof props.value === 'string' ? [props.value] : props.value ?? [];
  value.forEach((v,i) => {
    const index = props.columns[i]?.findIndex((item) => item.value === v);
    pickerSelectIndex.value[i] = index < 0 ? 0 : index;
  });  
  emit('selectTextChange', pickerSelectIndex.value.map((p, i) => {
    const cols = props.columns[i];
    if (!cols || cols.length === 0) 
      return null;
    return cols[p]?.text ?? cols[0]?.text ?? null;
  }).join(' '), true);
}

watch(() => props.value, (v) => {
  loadValues();
})
onMounted(() => {
  nextTick(() => {
    loadValues();
    loaded.value = true;
  })
})

const themeStyles = themeContext.useThemeStyles({
});

defineOptions({
  options: {
    styleIsolation: "shared",
    virtualHost: true,
  }
})
</script>

<style lang="scss">
.nana-form-picker {
  position: relative;
  display: flex;
  flex-direction: row;
  align-items: center;

  .picker-view {
    .item {
      text-align: center;
    }
  }
}
</style>