<template>
  <div>
    <gallery-search v-if="$uiStore.isModeSearch" :items="currentSearch" />
    <gallery-directory v-else-if="isDirectory" :directory="currentItem" />
    <gallery-image v-else-if="isImage" :image="currentItem" />
    <div v-else>Unknown type</div>
  </div>
</template>

<script lang="ts">
import { Component, Vue, Prop } from "vue-property-decorator";
import { Operation } from '@/@types/tag/Operation';
import GallerySearch from "./GallerySearch.vue";
import GalleryDirectory from "./GalleryDirectory.vue";
import GalleryImage from "./GalleryImage.vue";
import GalleryStore from "../store/galleryStore";

@Component({
  components: { GallerySearch, GalleryDirectory, GalleryImage },
})
export default class Gallery extends Vue {
  @Prop(String) readonly pathMatch!: string;

  get isDirectory(): boolean {
    return this.checkType("directory");
  }

  get isImage(): boolean {
    return this.checkType("image");
  }

  // Results of the search (by tags)
  get currentSearch(): Gallery.Item[] {
    const byOperation = this.extractTagsByOperation(this.$uiStore.currentTags);
    const intersection = this.extractIntersection(byOperation);
    const substraction = this.extractSubstraction(byOperation);
    return this.aggregateAll(byOperation, intersection, substraction);
  }

  // Item pointed by the URL (navigation)
  get currentItem(): Gallery.Item | null {
    const galleryItemsRoot = this.$galleryStore.galleryItemsRoot;
    if (galleryItemsRoot) return GalleryStore.searchCurrentItem(galleryItemsRoot, this.pathMatch);
    return null;
  }

  // ---

  private checkType(type: string): boolean {
    return this.currentItem?.properties.type === type ?? false;
  }

  private extractTagsByOperation(currentTags: Tag.Search[]): Tag.SearchByOperation {
    let byOperation: Tag.SearchByOperation = {};
    Object.values(Operation)
      .forEach(operation => byOperation[operation] = currentTags.filter(tag => tag.operation === operation));
    return byOperation;
  }

  private extractIntersection(byOperation: Tag.SearchByOperation): Set<Gallery.Item> {
    let intersection = new Set<Gallery.Item>();
    if (byOperation[Operation.INTERSECTION].length > 0) {
      byOperation[Operation.INTERSECTION]
        .map(tag => tag.items)
        .reduce((a,b) => a.filter(c => b.includes(c)))
        .flatMap(items=>items)
        .forEach(item => intersection.add(item));
    }
    return intersection;
  }

  private extractSubstraction(byOperation: Tag.SearchByOperation): Set<Gallery.Item> {
    let substraction = new Set<Gallery.Item>();
    if (byOperation[Operation.SUBSTRACTION].length > 0) {
      byOperation[Operation.SUBSTRACTION]
        .flatMap(tag => tag.items)
        .forEach(item => substraction.add(item));
    }
    return substraction;
  }

  private aggregateAll(byOperation: Tag.SearchByOperation, intersection: Set<Gallery.Item>, substraction: Set<Gallery.Item>): Gallery.Item[] {
    byOperation[Operation.ADDITION].flatMap(tag => tag.items).forEach(item => intersection.add(item));
    substraction.forEach(item => intersection.delete(item));
    return [...intersection];
  }
}
</script>

<style lang="scss">
</style>
