ytptube/ui/app/components/TextareaAutocomplete.vue

<template>
  <div
    class="dropdown"
    :class="{ 'is-active': showList && filteredOptions.length }"
    style="width: 100%"
  >
    <div class="control" style="width: 100%">
      <textarea
        :id="id"
        ref="textareaRef"
        v-model="localValue"
        @input="onInput"
        @focus="onFocus"
        @blur="hideList"
        @keydown="onKeydown"
        @keyup="updateCaret"
        @click="updateCaret"
        @mouseup="updateCaret"
        class="control is-fullwidth textarea"
        :placeholder="placeholder"
        autocomplete="off"
        style="width: 100%; position: relative; z-index: 2"
        rows="4"
        :disabled="disabled"
      />
    </div>
    <div class="dropdown-menu" role="menu" style="width: 100%; z-index: 3">
      <div class="dropdown-content" style="width: 100%; max-height: 11em; overflow-y: auto">
        <a
          v-for="(option, idx) in filteredOptions"
          :key="option.value"
          @mousedown.prevent="appendFlag(option.value)"
          :class="['dropdown-item', { 'is-active': idx === highlightedIndex }]"
          style="display: flex; justify-content: space-between"
          ref="dropdownItems"
        >
          <span class="has-text-weight-bold">{{ option.value }}</span>
          <span class="has-text-grey-light is-text-overflow" style="margin-left: 1em">{{
            option.description
          }}</span>
        </a>
      </div>
    </div>
  </div>
</template>

<script setup lang="ts">
import { ref, computed, watch, nextTick } from 'vue';
import type { AutoCompleteOptions } from '~/types/autocomplete';

const props = defineProps<{
  options: AutoCompleteOptions;
  placeholder?: string;
  disabled?: boolean;
  id?: string;
}>();

const model = defineModel<string>();
const localValue = ref(model.value || '');
const textareaRef = ref<HTMLTextAreaElement | null>(null);
const caretIndex = ref(0);
const showList = ref(false);
const highlightedIndex = ref(-1);
const dropdownItems = ref<HTMLElement[]>([]);

watch(model, (val) => (localValue.value = val || ''));
watch(localValue, (val) => (model.value = val));

// Compute token at caret position
const getCurrentToken = (value: string, caret: number) => {
  const left = value.slice(0, caret);
  const right = value.slice(caret);
  const leftMatch = left.match(/(\S+)$/);
  const rightMatch = right.match(/^(\S+)/);
  const leftToken: string = (leftMatch?.[1] ?? '') as string;
  const rightToken: string = (rightMatch?.[1] ?? '') as string;
  const token = leftToken + rightToken;
  const start = leftMatch ? caret - leftToken.length : caret;
  const end = rightMatch ? caret + rightToken.length : caret;
  return { token, start, end };
};

const filteredOptions = computed(() => {
  const { token } = getCurrentToken(localValue.value, caretIndex.value);
  // Hide suggestions once '=' is present in the current token
  if (!token || token.includes('=')) {
    return [];
  }
  // Only suggest when typing a long flag starting with `--`
  if (!token.startsWith('--')) {
    return [];
  }
  // Hide suggestions if token exactly matches an option value
  if (props.options.some((opt) => opt.value === token)) {
    return [];
  }
  const val = token.toLowerCase();
  const startsWithFlag = [];
  const includesFlag = [];
  const includesDesc = [];
  for (const opt of props.options) {
    const flag = opt.value.toLowerCase();
    const desc = opt.description.toLowerCase();
    if (flag.startsWith(val)) {
      startsWithFlag.push(opt);
    } else if (flag.includes(val)) {
      includesFlag.push(opt);
    } else if (desc.includes(val)) {
      includesDesc.push(opt);
    }
  }
  return [...startsWithFlag, ...includesFlag, ...includesDesc];
});

const appendFlag = (flag: string) => {
  const value = localValue.value;
  const caret = caretIndex.value;
  const { token, start, end } = getCurrentToken(value, caret);
  if (token) {
    // Replace only the flag part of the token, preserving any '=value' suffix in the same token
    const eqPos = token.indexOf('=');
    const after = eqPos !== -1 ? token.slice(eqPos) : '';
    localValue.value = value.slice(0, start) + flag + after + value.slice(end);
    nextTick(() => {
      const pos = start + flag.length + after.length;
      if (textareaRef.value) {
        textareaRef.value.selectionStart = textareaRef.value.selectionEnd = pos;
        caretIndex.value = pos;
      }
    });
  } else {
    // No token at caret: append at caret position
    const needsSpace = caret > 0 && value[caret - 1] !== ' ';
    localValue.value = value.slice(0, caret) + (needsSpace ? ' ' : '') + flag + value.slice(caret);
    nextTick(() => {
      const pos = caret + (needsSpace ? 1 : 0) + flag.length;
      if (textareaRef.value) {
        textareaRef.value.selectionStart = textareaRef.value.selectionEnd = pos;
        caretIndex.value = pos;
      }
    });
  }
  showList.value = false;
  highlightedIndex.value = -1;
};

const updateCaret = () => {
  caretIndex.value = textareaRef.value
    ? (textareaRef.value.selectionStart ?? localValue.value.length)
    : localValue.value.length;
};

const onFocus = () => {
  updateCaret();
  showList.value = true;
};

const onInput = () => {
  updateCaret();
  const { token } = getCurrentToken(localValue.value, caretIndex.value);
  const hasEqual = token.includes('=');
  const isFlagTrigger = token.startsWith('--') && !hasEqual;
  showList.value = isFlagTrigger && filteredOptions.value.length > 0;
  highlightedIndex.value = showList.value ? 0 : -1;
};

// Reset scroll position when filtered options change
watch(filteredOptions, () => {
  highlightedIndex.value = filteredOptions.value.length > 0 && showList.value ? 0 : -1;
  nextTick(() => {
    const dropdown = document.querySelector('.dropdown-content');
    if (dropdown) {
      dropdown.scrollTop = 0;
    }
    const items = document.querySelectorAll('.dropdown-item');
    dropdownItems.value = Array.from(items) as HTMLElement[];
  });
});

const hideList = () =>
  setTimeout(() => {
    showList.value = false;
    highlightedIndex.value = -1;
  }, 100);

const onKeydown = (e: KeyboardEvent) => {
  // Track caret and allow ESC to immediately close suggestions and restore normal keys
  updateCaret();
  if (e.key === 'Escape') {
    showList.value = false;
    highlightedIndex.value = -1;
    return;
  }
  if (!showList.value || !filteredOptions.value.length) {
    return;
  }

  const pageSize = 5;

  if (e.key === 'ArrowDown') {
    e.preventDefault();
    highlightedIndex.value = Math.min(highlightedIndex.value + 1, filteredOptions.value.length - 1);
    nextTick(() => {
      const el = dropdownItems.value[highlightedIndex.value];
      if (el) el.scrollIntoView({ block: 'nearest' });
    });
  } else if (e.key === 'ArrowUp') {
    e.preventDefault();
    highlightedIndex.value = Math.max(highlightedIndex.value - 1, 0);
    nextTick(() => {
      const el = dropdownItems.value[highlightedIndex.value];
      if (el) el.scrollIntoView({ block: 'nearest' });
    });
  } else if (e.key === 'PageDown') {
    e.preventDefault();
    highlightedIndex.value = Math.min(
      highlightedIndex.value + pageSize,
      filteredOptions.value.length - 1,
    );
    nextTick(() => {
      const el = dropdownItems.value[highlightedIndex.value];
      if (el) el.scrollIntoView({ block: 'nearest' });
    });
  } else if (e.key === 'PageUp') {
    e.preventDefault();
    highlightedIndex.value = Math.max(highlightedIndex.value - pageSize, 0);
    nextTick(() => {
      const el = dropdownItems.value[highlightedIndex.value];
      if (el) el.scrollIntoView({ block: 'nearest' });
    });
  } else if (e.key === 'Enter' || e.key === 'Tab') {
    const { token } = getCurrentToken(localValue.value, caretIndex.value);
    const hasEqual = token.includes('=');
    const isFlagTrigger = token.startsWith('--') && !hasEqual;
    const selected =
      highlightedIndex.value >= 0 && highlightedIndex.value < filteredOptions.value.length
        ? filteredOptions.value[highlightedIndex.value]
        : undefined;
    // Only autocomplete if there's a partial word being typed
    if (selected && isFlagTrigger) {
      e.preventDefault();
      appendFlag(selected.value);
    }
  }

  // dropdownItems is updated via a single top-level watch(filteredOptions)
};
</script>