<template>
  <div :class="containerClasses" class="select-none">
    <button
      v-for="(option, index) in options"
      :key="option.value"
      :type="type"
      :disabled="disabled"
      :class="getButtonClasses(option.value, index)"
      @click="handleSelect(option.value)"
    >
      <!-- Icon (optional) -->
      <span v-if="option.icon" class="mr-2" v-html="option.icon"/>

      <!-- Label -->
      <span>{{ option.label }}</span>

      <!-- Badge (optional) -->
      <span
        v-if="option.badge"
        class="ml-2 px-1.5 py-0.5 text-xs rounded-full bg-white/20"
      >
        {{ option.badge }}
      </span>
    </button>
  </div>
</template>

<script setup lang="ts">
import { computed } from 'vue'

export interface ButtonGroupOption {
  value: string
  label: string
  icon?: string  // SVG or emoji
  badge?: string | number
}

interface Props {
  options: ButtonGroupOption[]
  modelValue: string
  disabled?: boolean
  type?: 'button' | 'submit' | 'reset'
  size?: 'sm' | 'md' | 'lg'
  variant?: 'primary' | 'secondary'
  vertical?: boolean
}

const props = withDefaults(defineProps<Props>(), {
  disabled: false,
  type: 'button',
  size: 'md',
  variant: 'primary',
  vertical: false,
})

const emit = defineEmits<{
  'update:modelValue': [value: string]
}>()

const containerClasses = computed(() => {
  const base = 'inline-flex gap-0'
  const direction = props.vertical ? 'flex-col w-full' : 'flex-row flex-wrap'
  return `${base} ${direction}`
})

const getButtonClasses = (value: string, index: number) => {
  const isSelected = value === props.modelValue
  const isFirst = index === 0
  const isLast = index === props.options.length - 1

  // Base classes
  const base = 'relative inline-flex items-center justify-center font-medium transition-all duration-200 focus:outline-none focus:ring-2 focus:ring-offset-0 disabled:opacity-50 disabled:cursor-not-allowed border'

  // Size classes
  const sizeClasses = {
    sm: 'px-3 py-1.5 text-sm min-h-[36px]',
    md: 'px-4 py-2.5 text-base min-h-[44px]',
    lg: 'px-5 py-3 text-lg min-h-[52px]',
  }

  // Variant classes (selected vs unselected)
  let variantClasses = ''
  if (props.variant === 'primary') {
    variantClasses = isSelected
      ? 'bg-gradient-to-r from-primary to-blue-600 text-white border-blue-600 shadow-lg z-10'
      : 'bg-white text-gray-700 border-gray-300 hover:bg-gray-50'
  } else {
    variantClasses = isSelected
      ? 'bg-gradient-to-r from-gray-600 to-gray-700 text-white border-gray-600 shadow-lg z-10'
      : 'bg-white text-gray-700 border-gray-300 hover:bg-gray-50'
  }

  // Border radius (first and last buttons)
  let roundedClasses = ''
  if (props.vertical) {
    if (isFirst) roundedClasses = 'rounded-t-lg'
    if (isLast) roundedClasses = 'rounded-b-lg'
    if (!isFirst && !isLast) roundedClasses = ''
  } else {
    if (isFirst) roundedClasses = 'rounded-l-lg'
    if (isLast) roundedClasses = 'rounded-r-lg'
    if (!isFirst && !isLast) roundedClasses = ''
  }

  // Border handling (remove double borders)
  const borderClasses = !isFirst && !props.vertical ? '-ml-px' : ''

  // Width for vertical layout
  const widthClass = props.vertical ? 'w-full' : ''

  return [
    base,
    sizeClasses[props.size],
    variantClasses,
    roundedClasses,
    borderClasses,
    widthClass,
  ].join(' ')
}

const handleSelect = (value: string) => {
  if (!props.disabled) {
    emit('update:modelValue', value)
  }
}
</script>

<style scoped>
/* Prevent text selection on button group - critical for mobile UX */
:deep(button),
:deep(button *) {
  -webkit-user-select: none !important;
  -moz-user-select: none !important;
  -ms-user-select: none !important;
  user-select: none !important;
  -webkit-touch-callout: none !important;
}

button {
  touch-action: manipulation;
}
</style>
