/**
 * Copyright Aquera Inc 2025
 *
 * This source code is licensed under the BSD-3-Clause license found in the
 * LICENSE file in the root directory of this source tree.
 */

import { html, type TemplateResult } from 'lit';
import { virtualize } from '@lit-labs/virtualizer/virtualize.js';
import { unsafeHTML } from 'lit/directives/unsafe-html.js';
import { ifDefined } from 'lit/directives/if-defined.js';
import { classMap } from 'lit/directives/class-map.js';

export class VirtualSelectRenderer {
  static getVirtualizedContent(
    data: any[], 
    searchEnabled: boolean, 
    renderItemFunction: (item: any) => string,
    value: string | string[],
    multiple: boolean,
    getDisplayText?: (item: any) => string,
    getItemValue?: (item: any) => string,
    getItemDescription?: (item: any) => string,
    getItemPrefix?: (item: any) => string,
    getItemSuffix?: (item: any) => string,
    showNoResults?: boolean,
    noResultsMessage?: string,
    loading?: boolean,
    onScroll?: (e: Event) => void,
    allowHtmlLabel?: boolean,
    enableDescription?: boolean
  ): TemplateResult {
    return html`
      <div part="select-options" class="select__options ${
        searchEnabled ? 'select__options__search-enabled' : ``
      } ${loading ? 'loading' : ''}">
        ${showNoResults && !loading
          ? html`
              <div part="select-no-results" class="select__no-results">
                ${noResultsMessage || 'No results found'}
              </div>
            `
          : html`
              <div
                class="virtualized"
                part="virtualized"
                @scroll=${onScroll}
              >
                ${VirtualSelectRenderer.shouldUseVirtualizer(data)
                  ? html`
                      ${virtualize({
                        items: data,
                        renderItem: (item: any): TemplateResult =>
                          VirtualSelectRenderer.getItemRenderFunction(item, renderItemFunction, value, multiple, getDisplayText, getItemValue, getItemDescription, getItemPrefix, getItemSuffix, allowHtmlLabel, enableDescription),
                        scroller: true,
                      })}
                    `
                  : html`
                      ${data.map((item: any) => 
                        VirtualSelectRenderer.getItemRenderFunction(item, renderItemFunction, value, multiple, getDisplayText, getItemValue, getItemDescription, getItemPrefix, getItemSuffix, allowHtmlLabel, enableDescription)
                      )}
                    `}
              </div>
            `}
      </div>`;
  }

  static getItemRenderFunction(
    item: any, 
    renderItemFunction: (item: any) => string, 
    value: string | string[], 
    multiple: boolean,
    getDisplayText?: (item: any) => string,
    getItemValue?: (item: any) => string,
    getItemDescription?: (item: any) => string,
    getItemPrefix?: (item: any) => string,
    getItemSuffix?: (item: any) => string,
    allowHtmlLabel?: boolean,
    enableDescription?: boolean,
  ): TemplateResult {
    if(!item) {
      return html``;
    }
    const displayTextFn = getDisplayText || renderItemFunction;
    const valueFn = getItemValue || ((item: any) => item?.value || item);
    
    const optionValue = valueFn(item);
    const displayText = displayTextFn(item);
    const isDisabled = item?.disabled || false;
    const className = item?.className;
    const description = (getItemDescription ? getItemDescription(item) : item?.description) ?? '';
    const prefix = (getItemPrefix ? getItemPrefix(item) : item?.prefix) ?? '';
    const suffix = (getItemSuffix ? getItemSuffix(item) : item?.suffix) ?? '';
    
    let isSelected = false;
    if (multiple) {
      isSelected = Array.isArray(value) && value.some(v => String(v) === String(optionValue));
    } else {
      isSelected = (Array.isArray(value) ? value[0] : value) === optionValue;
    }

    return html`
      <nile-option
        value=${optionValue} 
        .selected=${isSelected} 
        .disabled=${isDisabled}
        .showCheckbox=${multiple}
        class=${classMap({
          option: enableDescription ?? false,
          [className ?? '']: !!className,
        })}
        .description=${description}
        .isDescriptionEnabled=${enableDescription}
      >
        ${unsafeHTML(prefix)}
        ${allowHtmlLabel ? unsafeHTML(displayText) : displayText}
        ${unsafeHTML(suffix)}
      </nile-option>
    `;
  }

  /**
   * Determines whether to use virtualizer based on dataset size
   * For small datasets (less than 5 items), use regular rendering for better sizing
   */
  private static shouldUseVirtualizer(data: any[]): boolean {
    return data.length >= 5;
  }
}