<script lang="ts">
  /**
   * The FilterView shows the various options to enable/disable a single layer or to only show a subset of the data.
   */
  import type FilteredLayer from "../../Models/FilteredLayer"
  import LayerConfig from "../../Models/ThemeConfig/LayerConfig"
  import ToSvelte from "../Base/ToSvelte.svelte"
  import Checkbox from "../Base/Checkbox.svelte"
  import FilterConfig from "../../Models/ThemeConfig/FilterConfig"
  import type { Writable } from "svelte/store"
  import If from "../Base/If.svelte"
  import Dropdown from "../Base/Dropdown.svelte"
  import { onDestroy } from "svelte"
  import { ImmutableStore, Store } from "../../Logic/UIEventSource"
  import FilterviewWithFields from "./FilterviewWithFields.svelte"
  import Tr from "../Base/Tr.svelte"
  import Translations from "../i18n/Translations"

  export let filteredLayer: FilteredLayer
  export let highlightedLayer: Store<string | undefined> = new ImmutableStore(undefined)
  export let zoomlevel: Store<number> = new ImmutableStore(22)
  let layer: LayerConfig = filteredLayer.layerDef
  let isDisplayed: Store<boolean> = filteredLayer.isDisplayed

  /**
   * Gets a UIEventSource as boolean for the given option, to be used with a checkbox
   */
  function getBooleanStateFor(option: FilterConfig): Writable<boolean> {
    const state = filteredLayer.appliedFilters.get(option.id)
    return state.sync(
      (f) => f === 0,
      [],
      (b) => (b ? 0 : undefined)
    )
  }

  /**
   * Gets a UIEventSource as number for the given option, to be used with a dropdown or radiobutton
   */
  function getStateFor(option: FilterConfig): Writable<number> {
    return filteredLayer.appliedFilters.get(option.id)
  }

  let mainElem: HTMLElement
  $: onDestroy(
    highlightedLayer.addCallbackAndRun((highlightedLayer) => {
      if (highlightedLayer === filteredLayer.layerDef.id) {
        mainElem?.classList?.add("glowing-shadow")
      } else {
        mainElem?.classList?.remove("glowing-shadow")
      }
    })
  )
</script>

{#if filteredLayer.layerDef.name}
  <div bind:this={mainElem} class="mb-1.5">
    <label class="flex gap-1 no-image-background">
      <Checkbox selected={isDisplayed} />
      <If condition={filteredLayer.isDisplayed}>
        <ToSvelte
          construct={() => layer.defaultIcon()?.SetClass("block h-6 w-6 no-image-background")}
        />
        <ToSvelte
          slot="else"
          construct={() =>
            layer.defaultIcon()?.SetClass("block h-6 w-6 no-image-background opacity-50")}
        />
      </If>

      {filteredLayer.layerDef.name}

      {#if $zoomlevel < layer.minzoom}
        <span class="alert">
          <Tr t={Translations.t.general.layerSelection.zoomInToSeeThisLayer} />
        </span>
      {/if}
    </label>

    {#if $isDisplayed && filteredLayer.layerDef.filters?.length > 0}
      <div id="subfilters" class="flex flex-col gap-y-1 ml-4">
        {#each filteredLayer.layerDef.filters as filter}
          <div>
            <!-- There are three (and a half) modes of filters: a single checkbox, a radio button/dropdown or with searchable fields -->
            {#if filter.options.length === 1 && filter.options[0].fields.length === 0}
              <label>
                <Checkbox selected={getBooleanStateFor(filter)} />
                {filter.options[0].question}
              </label>
            {/if}

            {#if filter.options.length === 1 && filter.options[0].fields.length > 0}
              <FilterviewWithFields id={filter.id} {filteredLayer} option={filter.options[0]} />
            {/if}

            {#if filter.options.length > 1}
              <Dropdown value={getStateFor(filter)}>
                {#each filter.options as option, i}
                  <option value={i}>
                    {option.question}
                  </option>
                {/each}
              </Dropdown>
            {/if}
          </div>
        {/each}
      </div>
    {/if}
  </div>
{/if}
