<template>
  <div class="panel">
    <div class="panel-header">
      <div class="panel-title-row">
        <div class="panel-title-row">
          <h2 class="panel-title">
            All items
          </h2>
          <span v-if="total" class="item-count">{{ total }}</span>
        </div>
        <button class="btn-primary" @click="showAddModal = true">
          <svg width="11" height="11" viewBox="0 0 11 11" fill="none" aria-hidden="true">
            <path d="M5.5 1V10M1 5.5H10" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" />
          </svg>
          Add item
        </button>
      </div>
      <div class="search-wrap">
        <span class="search-icon" aria-hidden="true">
          <svg width="13" height="13" viewBox="0 0 13 13" fill="none">
            <circle cx="5.5" cy="5.5" r="4" stroke="currentColor" stroke-width="1.4" />
            <path d="M8.5 8.5L11.5 11.5" stroke="currentColor" stroke-width="1.4" stroke-linecap="round" />
          </svg>
        </span>
        <input
          class="search-input"
          type="text"
          placeholder="Search..."
          :value="search"
          @input="onSearchInput"
        >
      </div>
    </div>

    <div class="panel-body">
      <ul class="item-list">
        <li
          v-for="(item, index) in items"
          :key="item.id"
          class="item-row"
          :style="{ '--i': Math.min(index, 14) }"
        >
          <span class="item-id">#{{ item.id }}</span>
          <span class="item-value">{{ item.value }}</span>
          <button class="action-btn" title="Move to selected" @click="emit('select', item.id!)">
            <svg width="14" height="14" viewBox="0 0 14 14" fill="none" aria-hidden="true">
              <path d="M2.5 7H11.5M8.5 3.5L12 7L8.5 10.5" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round" />
            </svg>
          </button>
        </li>
      </ul>

      <div v-if="loading" class="status-row">
        <span class="status-dots">
          <span /><span /><span />
        </span>
      </div>
      <div v-if="hasMore && !loading" ref="sentinel" class="sentinel" />
      <div v-if="!loading && !hasMore && items.length === 0" class="empty-state">
        <span class="empty-label">No items found</span>
      </div>
    </div>

    <Transition name="modal">
      <div v-if="showAddModal" class="modal-overlay" @click.self="closeModal">
        <div class="modal-card">
          <div class="modal-header">
            <p class="modal-title">
              Add new item
            </p>
            <button class="modal-close" aria-label="Close" @click="closeModal">
              <svg width="13" height="13" viewBox="0 0 13 13" fill="none" aria-hidden="true">
                <path d="M1.5 1.5L11.5 11.5M11.5 1.5L1.5 11.5" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" />
              </svg>
            </button>
          </div>
          <input
            v-model.number="addIdInput"
            class="modal-input"
            type="number"
            placeholder="Enter item ID"
            @keydown.enter="submitAdd"
          >
          <div class="modal-footer">
            <button class="btn-ghost" @click="closeModal">
              Cancel
            </button>
            <button class="btn-primary" @click="submitAdd">
              Add item
            </button>
          </div>
        </div>
      </div>
    </Transition>
  </div>
</template>

<script setup lang="ts">
import type { Item } from '~/services/api'
import { onUnmounted, ref, watch } from 'vue'

const props = defineProps<{
  items: Item[]
  total: number | string
  loading: boolean
  hasMore: boolean
  search: string
}>()

const emit = defineEmits<{
  (e: 'update:search', val: string): void
  (e: 'loadMore'): void
  (e: 'select', id: number): void
  (e: 'add', id: number): void
}>()

const sentinel = ref<HTMLElement | null>(null)
const showAddModal = ref(false)
const addIdInput = ref<number | null>(null)
let observer: IntersectionObserver | null = null

watch(sentinel, (el) => {
  if (observer) {
    observer.disconnect()
    observer = null
  }
  if (el) {
    observer = new IntersectionObserver((entries) => {
      if (entries[0]?.isIntersecting && props.hasMore && !props.loading) {
        emit('loadMore')
      }
    }, { threshold: 0.1 })
    observer.observe(el)
  }
})

onUnmounted(() => {
  observer?.disconnect()
})

let debounceTimer: ReturnType<typeof setTimeout> | null = null

function onSearchInput(e: Event) {
  const val = (e.target as HTMLInputElement).value
  if (debounceTimer)
    clearTimeout(debounceTimer)
  debounceTimer = setTimeout(() => {
    emit('update:search', val)
  }, 300)
}

function closeModal() {
  showAddModal.value = false
  addIdInput.value = null
}

function submitAdd() {
  if (addIdInput.value !== null && Number.isInteger(addIdInput.value)) {
    emit('add', addIdInput.value)
    addIdInput.value = null
    showAddModal.value = false
  }
}
</script>

<style scoped lang="scss">
.panel {
  display: flex;
  flex-direction: column;
  height: 100%;
  background: var(--surface);
  border-right: 1px solid var(--border);
}

/* ── Header ── */
.panel-header {
  height: 108px;
  padding: 18px 20px 16px;
  border-bottom: 1px solid var(--border);
  background: var(--surface);
  flex-shrink: 0;
}

.item-count {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-left: 8px;
  min-width: 18px;
  height: 18px;
  padding: 0 5px;
  background: var(--surface-subtle);
  border: 1px solid var(--border);
  border-radius: 9999px;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  color: var(--text-secondary);
}

.panel-title-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 12px;
}

.panel-title {
  margin: 0;
  font-size: 0.72rem;
  font-weight: 500;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-secondary);
  font-family: var(--font-sans);
}

.search-wrap {
  position: relative;
  display: flex;
  align-items: center;
}

.search-icon {
  position: absolute;
  left: 10px;
  display: flex;
  align-items: center;
  color: var(--text-muted);
  pointer-events: none;
}

.search-input {
  width: 100%;
  padding: 7px 12px 7px 30px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--surface-subtle);
  font-family: var(--font-sans);
  font-size: 0.825rem;
  color: var(--text-primary);
  outline: none;
  transition:
    border-color 150ms ease,
    background 150ms ease;

  &::placeholder {
    color: var(--text-muted);
  }

  &:focus {
    border-color: var(--text-primary);
    background: var(--surface);
  }
}

/* ── Buttons ── */
.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  background: var(--text-primary);
  color: #ffffff;
  border: none;
  border-radius: var(--radius-sm);
  font-family: var(--font-sans);
  font-size: 0.78rem;
  font-weight: 500;
  cursor: pointer;
  letter-spacing: 0.01em;
  white-space: nowrap;
  transition:
    background 150ms ease,
    transform 100ms ease;

  &:hover {
    background: #333333;
  }

  &:active {
    transform: scale(0.97);
  }
}

.btn-ghost {
  padding: 7px 14px;
  background: none;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-family: var(--font-sans);
  font-size: 0.825rem;
  color: var(--text-secondary);
  cursor: pointer;
  transition:
    color 150ms ease,
    border-color 150ms ease,
    background 150ms ease;

  &:hover {
    color: var(--text-primary);
    border-color: #999;
    background: var(--surface-subtle);
  }
}

/* ── Body & list ── */
.panel-body {
  flex: 1;
  overflow-y: auto;

  &::-webkit-scrollbar {
    width: 3px;
  }
  &::-webkit-scrollbar-track {
    background: transparent;
  }
  &::-webkit-scrollbar-thumb {
    background: var(--border);
    border-radius: 2px;
  }
}

.item-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

@keyframes item-in {
  from {
    opacity: 0;
    transform: translateY(6px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.item-row {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 9px 12px 9px 20px;
  border-bottom: 1px solid var(--border);
  animation: item-in 350ms cubic-bezier(0.16, 1, 0.3, 1) both;
  animation-delay: calc(var(--i, 0) * 25ms);
  transition: background 120ms ease;

  &:hover {
    background: var(--surface-subtle);

    .action-btn {
      opacity: 1;
    }
  }
}

.item-id {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-muted);
  flex-shrink: 0;
  min-width: 44px;
}

.item-value {
  flex: 1;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-primary);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.action-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  background: none;
  border: none;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  cursor: pointer;
  opacity: 0;
  transition:
    color 120ms ease,
    background 120ms ease,
    opacity 120ms ease;

  &:hover {
    color: var(--text-primary);
    background: var(--border);
  }
}

/* ── States ── */
.status-row {
  display: flex;
  justify-content: center;
  padding: 24px;
}

.status-dots {
  display: flex;
  gap: 5px;
  align-items: center;

  span {
    width: 4px;
    height: 4px;
    border-radius: 50%;
    background: var(--text-muted);
    animation: dot-blink 1.2s ease-in-out infinite;

    &:nth-child(2) {
      animation-delay: 0.2s;
    }
    &:nth-child(3) {
      animation-delay: 0.4s;
    }
  }
}

@keyframes dot-blink {
  0%,
  80%,
  100% {
    opacity: 0.25;
  }
  40% {
    opacity: 1;
  }
}

.empty-state {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 56px 24px;
}

.empty-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  letter-spacing: 0.02em;
}

.sentinel {
  height: 1px;
}

/* ── Modal ── */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.24);
  backdrop-filter: blur(2px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 200;
}

.modal-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 28px;
  min-width: 340px;
  box-shadow: 0 4px 32px rgba(0, 0, 0, 0.06);
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 20px;
}

.modal-title {
  margin: 0;
  font-size: 0.88rem;
  font-weight: 500;
  color: var(--text-primary);
  letter-spacing: -0.01em;
}

.modal-close {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  background: none;
  border: none;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  cursor: pointer;
  transition:
    color 120ms ease,
    background 120ms ease;

  &:hover {
    color: var(--text-primary);
    background: var(--surface-subtle);
  }
}

.modal-input {
  width: 100%;
  padding: 9px 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--surface-subtle);
  font-family: var(--font-mono);
  font-size: 0.875rem;
  color: var(--text-primary);
  outline: none;
  transition:
    border-color 150ms ease,
    background 150ms ease;

  &::placeholder {
    color: var(--text-muted);
    font-family: var(--font-sans);
  }

  &:focus {
    border-color: var(--text-primary);
    background: var(--surface);
  }

  &::-webkit-inner-spin-button,
  &::-webkit-outer-spin-button {
    -webkit-appearance: none;
  }
}

.modal-footer {
  display: flex;
  gap: 8px;
  justify-content: flex-end;
  margin-top: 20px;
}

/* Modal enter/leave transition */
.modal-enter-active {
  transition: opacity 180ms ease;

  .modal-card {
    transition:
      transform 220ms cubic-bezier(0.16, 1, 0.3, 1),
      opacity 180ms ease;
  }
}

.modal-leave-active {
  transition: opacity 150ms ease;

  .modal-card {
    transition:
      transform 150ms ease,
      opacity 150ms ease;
  }
}

.modal-enter-from,
.modal-leave-to {
  opacity: 0;

  .modal-card {
    transform: translateY(10px) scale(0.98);
    opacity: 0;
  }
}
</style>
