<template>
  <div class="tab-page" :class="[`tab-page-${tabPosition}`]">
    <!-- 顶部标签栏 -->
    <div v-if="tabPosition === 'top' && showTabs && panels && panels.length > 0" class="tab-header tab-header-horizontal">
      <div 
        v-for="(panel, index) in panels" 
        :key="panel.id"
        :class="['tab-item', { 'active': activeTabIndex === index }]"
        @click="setActiveTab(index)"
        @mousedown="onTabDragStart(index, $event)"
      >
        <div class="flex items-center justify-between h-full px-3">
          <span class="tab-title">{{ panel.title }}</span>
          <!-- 当标签页未被激活时显示关闭按钮 -->
          <button 
            v-if="activeTabIndex !== index"
            class="button-icon p-[2px] rounded hover:opacity-100 opacity-80"
            @click.stop="closeTab(panel.id)"
            aria-label="关闭"
          >
            <svg width="11" height="11" viewBox="0 0 11 11" aria-hidden="true">
              <line x1="2" y1="2" x2="9" y2="9" stroke="#e6efff" stroke-width="1" />
              <line x1="2" y1="9" x2="9" y2="2" stroke="#e6efff" stroke-width="1" />
            </svg>
          </button>
        </div>
      </div>
      <div class="tab-placeholder"></div>
    </div>

    <!-- 左侧标签栏 -->
    <div v-if="tabPosition === 'left' && showTabs && panels && panels.length > 0" class="tab-header tab-header-vertical tab-header-left">
      <div 
        v-for="(panel, index) in panels" 
        :key="panel.id"
        :class="['tab-item-vertical', { 'active': activeTabIndex === index }]"
        @click="setActiveTab(index)"
        @mousedown="onTabDragStart(index, $event)"
      >
        <div class="flex flex-col items-center justify-center w-full h-full py-2">
          <span class="tab-title-vertical">{{ panel.title }}</span>
          <!-- 当标签页未被激活时显示关闭按钮 -->
          <button 
            v-if="activeTabIndex !== index"
            class="button-icon p-[2px] rounded hover:opacity-100 opacity-80 mt-1"
            @click.stop="closeTab(panel.id)"
            aria-label="关闭"
          >
            <svg width="11" height="11" viewBox="0 0 11 11" aria-hidden="true">
              <line x1="2" y1="2" x2="9" y2="9" stroke="#e6efff" stroke-width="1" />
              <line x1="2" y1="9" x2="9" y2="2" stroke="#e6efff" stroke-width="1" />
            </svg>
          </button>
        </div>
      </div>
      <div class="tab-placeholder"></div>
    </div>

    <!-- Tab页内容区域 -->
    <div class="tab-content">
      <!-- 渲染slot内容（Panel组件） -->
      <slot></slot>
    </div>

    <!-- 右侧标签栏 -->
    <div v-if="tabPosition === 'right' && showTabs && panels && panels.length > 0" class="tab-header tab-header-vertical tab-header-right">
      <div 
        v-for="(panel, index) in panels" 
        :key="panel.id"
        :class="['tab-item-vertical', { 'active': activeTabIndex === index }]"
        @click="setActiveTab(index)"
        @mousedown="onTabDragStart(index, $event)"
      >
        <div class="flex flex-col items-center justify-center w-full h-full py-2">
          <span class="tab-title-vertical">{{ panel.title }}</span>
          <!-- 当标签页未被激活时显示关闭按钮 -->
          <button 
            v-if="activeTabIndex !== index"
            class="button-icon p-[2px] rounded hover:opacity-100 opacity-80 mt-1"
            @click.stop="closeTab(panel.id)"
            aria-label="关闭"
          >
            <svg width="11" height="11" viewBox="0 0 11 11" aria-hidden="true">
              <line x1="2" y1="2" x2="9" y2="9" stroke="#e6efff" stroke-width="1" />
              <line x1="2" y1="9" x2="9" y2="2" stroke="#e6efff" stroke-width="1" />
            </svg>
          </button>
        </div>
      </div>
      <div class="tab-placeholder"></div>
    </div>

    <!-- 底部标签栏 -->
    <div v-if="tabPosition === 'bottom' && showTabs && panels && panels.length > 0" class="tab-header tab-header-horizontal tab-header-bottom">
      <div 
        v-for="(panel, index) in panels" 
        :key="panel.id"
        :class="['tab-item', { 'active': activeTabIndex === index }]"
        @click="setActiveTab(index)"
        @mousedown="onTabDragStart(index, $event)"
      >
        <div class="flex items-center justify-between h-full px-3">
          <span class="tab-title">{{ panel.title }}</span>
          <!-- 当标签页未被激活时显示关闭按钮 -->
          <button 
            v-if="activeTabIndex !== index"
            class="button-icon p-[2px] rounded hover:opacity-100 opacity-80"
            @click.stop="closeTab(panel.id)"
            aria-label="关闭"
          >
            <svg width="11" height="11" viewBox="0 0 11 11" aria-hidden="true">
              <line x1="2" y1="2" x2="9" y2="9" stroke="#e6efff" stroke-width="1" />
              <line x1="2" y1="9" x2="9" y2="2" stroke="#e6efff" stroke-width="1" />
            </svg>
          </button>
        </div>
      </div>
      <div class="tab-placeholder"></div>
    </div>
  </div>
</template>

<script setup>
import { defineProps, defineEmits, ref, onMounted } from 'vue'

const props = defineProps({
  id: { type: String, required: true },
  title: { type: String, default: '标签页' },
  // 从父组件传入的面板数组
  panels: {
    type: Array,
    default: () => []
  },
  // 是否显示页标签栏
  showTabs: {
    type: Boolean,
    default: true
  },
  // 标签页位置：top(顶部), right(右侧), bottom(底部), left(左侧)
  tabPosition: {
    type: String,
    default: 'top',
    validator: (value) => ['top', 'right', 'bottom', 'left'].includes(value)
  }
})

const emit = defineEmits(['tabChange', 'tabClose', 'tabAdd', 'tabDragStart', 'tabDragMove', 'tabDragEnd'])

// 当前激活的标签页索引
const activeTabIndex = ref(-1)

// 拖拽相关状态
let isDragging = false
let dragIndex = -1

// 设置激活的标签页
const setActiveTab = (index) => {
  if (index >= 0 && index < props.panels.length) {
    activeTabIndex.value = index
    emit('tabChange', { index, tab: props.panels[index] })
  }
}

// 组件挂载后，如果有面板且没有激活的标签，默认激活第一个
onMounted(() => {
  if (props.panels && props.panels.length > 0 && activeTabIndex.value === -1) {
    setActiveTab(0)
  }
})

// 关闭标签页
const closeTab = (tabId) => {
  emit('tabClose', { id: tabId })
}

// 标签拖拽开始
const onTabDragStart = (index, event) => {
  // 只有当点击的是标题文本区域（不是关闭按钮）时才触发拖拽
  if (!event.target.closest('.button-icon') && !event.target.closest('button')) {
    isDragging = true
    dragIndex = index
    
    // 传递标签页索引和鼠标位置
    emit('tabDragStart', {
      clientX: event.clientX,
      clientY: event.clientY,
      tabIndex: index,
      tabId: props.panels[index].id
    })
    
    // 防止文本选择和默认行为
    event.preventDefault()
    event.stopPropagation()
    
    // 将鼠标移动和释放事件绑定到document，确保拖拽的连续性
    document.addEventListener('mousemove', onTabDragMove)
    document.addEventListener('mouseup', onTabDragEnd)
    document.addEventListener('mouseleave', onTabDragEnd)
  }
}

// 标签拖拽移动
const onTabDragMove = (event) => {
  if (isDragging) {
    // 防止文本选择和默认行为
    event.preventDefault()
    event.stopPropagation()
    emit('tabDragMove', {
      clientX: event.clientX,
      clientY: event.clientY,
      tabIndex: dragIndex
    })
  }
}

// 标签拖拽结束
const onTabDragEnd = () => {
  if (isDragging) {
    isDragging = false
    emit('tabDragEnd', { tabIndex: dragIndex })
    dragIndex = -1
    
    // 拖拽结束后移除事件监听器
    document.removeEventListener('mousemove', onTabDragMove)
    document.removeEventListener('mouseup', onTabDragEnd)
    document.removeEventListener('mouseleave', onTabDragEnd)
  }
}
</script>

<style scoped>
/* 主容器样式 */
.tab-page {
  display: flex;
  width: 100%;
  height: 100%;
  background: #5D6B99;
  border: 0px solid #c7d2ea;
  border-radius: 0;
  overflow: hidden;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

/* 顶部和底部位置：水平布局 */
.tab-page-top,
.tab-page-bottom {
  flex-direction: column;
}

/* 左侧和右侧位置：水平布局但标签栏垂直 */
.tab-page-left,
.tab-page-right {
  flex-direction: row;
}

:root {
  --vs-blue-top: #4f72b3;
  --vs-blue-bottom: #3c5a99;
}

/* 水平标签栏样式 */
.tab-header-horizontal {
  display: flex;
  flex-wrap: nowrap;
  height: 28px;
  background: transparent;
  overflow-x: auto;
  overflow-y: hidden;
  padding-top: 2px;
}

.tab-header-bottom {
  border-top: none;
  border-bottom: none;
  padding-top: 0;
  padding-bottom: 2px;
}

/* 垂直标签栏样式 */
.tab-header-vertical {
  display: flex;
  flex-wrap: nowrap;
  width: 28px;
  background: transparent;
  overflow-x: hidden;
  overflow-y: auto;
  padding-left: 2px;
}

.tab-header-right {
  flex-direction: column;
  padding-left: 0;
  padding-right: 2px;
}

/* 水平标签项样式 */
.tab-item {
  height: 26px;
  margin-left: 1px;
  background: linear-gradient(to bottom, var(--vs-blue-top), var(--vs-blue-bottom));
  border-radius: 3px 3px 0 0;
  cursor: pointer;
  white-space: nowrap;
  color: white;
  font-size: 12px;
  user-select: none;
  min-width: 60px;
  display: flex;
  align-items: center;
}

/* 底部位置的特殊样式 */
.tab-page-bottom .tab-item {
  border-radius: 0 0 3px 3px;
}

.tab-title {
  flex: 1;
  text-align: left;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  margin-right: 8px;
}

/* 垂直标签项样式 */
.tab-item-vertical {
  width: 26px;
  height: 60px;
  margin-top: 1px;
  background: linear-gradient(to right, var(--vs-blue-top), var(--vs-blue-bottom));
  border-radius: 3px 0 0 3px;
  cursor: pointer;
  white-space: nowrap;
  color: white;
  font-size: 12px;
  user-select: none;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* 右侧位置的特殊样式 */
.tab-page-right .tab-item-vertical {
  border-radius: 0 3px 3px 0;
  background: linear-gradient(to left, var(--vs-blue-top), var(--vs-blue-bottom));
}

.tab-title-vertical {
  text-align: center;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  margin: 0 4px;
  writing-mode: vertical-rl;
  text-orientation: mixed;
}

/* 活动标签样式 */
.tab-item.active,
.tab-item-vertical.active {
  background: #F5CC84;
  border: 1px solid #c7d2ea;
  color: #000000;
  font-weight: 500;
  cursor: move;
}

/* 顶部位置活动标签 */
.tab-page-top .tab-item.active {
  border-bottom-color: #F5CC84;
  border-top-width: 2px;
  border-top-color: #0078d7;
}

/* 底部位置活动标签 */
.tab-page-bottom .tab-item.active {
  border-top-color: #F5CC84;
  border-bottom-width: 2px;
  border-bottom-color: #0078d7;
}

/* 左侧位置活动标签 */
.tab-page-left .tab-item-vertical.active {
  border-right-color: #F5CC84;
  border-left-width: 2px;
  border-left-color: #0078d7;
}

/* 右侧位置活动标签 */
.tab-page-right .tab-item-vertical.active {
  border-left-color: #F5CC84;
  border-right-width: 2px;
  border-right-color: #0078d7;
}

/* 悬停样式 */
.tab-item:hover,
.tab-item-vertical:hover {
  background: linear-gradient(to bottom, #5a7db8, #4667a4);
}

.tab-page-right .tab-item-vertical:hover {
  background: linear-gradient(to left, #5a7db8, #4667a4);
}

.tab-item.active:hover,
.tab-item-vertical.active:hover {
  background: #F5CC84;
  color: #000000;
}

/* 按钮样式 */
.button-icon {
  background: transparent;
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* 确保在活动标签页中的按钮样式正确 */
.tab-item.active .button-icon,
.tab-item-vertical.active .button-icon {
  opacity: 0.6;
}

.tab-item.active .button-icon:hover,
.tab-item-vertical.active .button-icon:hover {
  opacity: 1;
  background: #f3f4f6;
}

/* 确保在非活动标签页中的按钮样式正确 */
.tab-item:not(.active) .button-icon svg line,
.tab-item-vertical:not(.active) .button-icon svg line {
  stroke: #e6efff;
}

.tab-item:not(.active) .button-icon:hover svg line,
.tab-item-vertical:not(.active) .button-icon:hover svg line {
  stroke: white;
}

.tab-placeholder {
  background: transparent;
  border: transparent;
}

/* 内容区域样式 */
.tab-content {
  flex: 1;
  position: relative;
  overflow: hidden;
}

.tab-panel {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  padding: 12px;
  overflow: auto;
  background: #ffffff;
  display: none;
}

.tab-panel.active {
  display: block;
}

.tab-empty {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 100%;
  color: #999;
  font-size: 14px;
}

/* 滚动条样式 - 水平标签栏 */
.tab-header-horizontal::-webkit-scrollbar {
  height: 6px;
}

.tab-header-horizontal::-webkit-scrollbar-track {
  background: #f0f0f0;
}

.tab-header-horizontal::-webkit-scrollbar-thumb {
  background: #c7d2ea;
  border-radius: 3px;
}

/* 滚动条样式 - 垂直标签栏 */
.tab-header-vertical::-webkit-scrollbar {
  width: 6px;
}

.tab-header-vertical::-webkit-scrollbar-track {
  background: #f0f0f0;
}

.tab-header-vertical::-webkit-scrollbar-thumb {
  background: #c7d2ea;
  border-radius: 3px;
}

/* 内容区域滚动条 */
.tab-panel::-webkit-scrollbar {
  width: 12px;
  height: 12px;
}

.tab-panel::-webkit-scrollbar-track {
  background: #f5f7fb;
}

.tab-panel::-webkit-scrollbar-thumb {
  background: linear-gradient(to bottom, #d0d6ea, #c0c7e0);
  border: 1px solid #b0b6d6;
  border-radius: 6px;
}

.tab-panel::-webkit-scrollbar-thumb:hover {
  background: linear-gradient(to bottom, #c1c7e2, #b2b8d9);
}
</style>