import React from 'react'
import { useTranslation } from '../i18n'

/**
 * LoadingSpinner
 *
 * 兽医主题加载动画组件。
 * 支持三种风格：paw（爪印）、heartbeat（心跳线）、dna（DNA 双螺旋）
 *
 * Props:
 *   size    - 尺寸：'sm' (24px) / 'md' (40px) / 'lg' (64px)
 *   variant - 风格：'paw' / 'heartbeat' / 'dna' / 'spinner'（默认 paw）
 *   label   - 无障碍文本，默认 "加载中..."
 *   className - 额外的包裹层 class
 *   colorClass - 自定义颜色类（如 'text-blue-500'）
 */

export type SpinnerSize = 'sm' | 'md' | 'lg'
export type SpinnerVariant = 'paw' | 'heartbeat' | 'dna' | 'spinner'

interface LoadingSpinnerProps {
  size?: SpinnerSize
  variant?: SpinnerVariant
  label?: string
  className?: string
  colorClass?: string
}

const SIZE_MAP: Record<SpinnerSize, number> = {
  sm: 24,
  md: 40,
  lg: 64,
}

/** 爪印动画 SVG */
function PawSpinner({ size, colorClass }: { size: number; colorClass: string }) {
  const scale = size / 48
  return (
    <svg
      className={`animate-spin-slow ${colorClass}`}
      width={size}
      height={size}
      viewBox="0 0 48 48"
      fill="none"
      xmlns="http://www.w3.org/2000/svg"
      style={{ transform: `scale(${scale})`, transformOrigin: 'center' }}
    >
      <g style={{ animation: 'paw-bounce 1.2s ease-in-out infinite' }}>
        {/* 主肉垫 */}
        <ellipse cx="24" cy="30" rx="10" ry="8" fill="currentColor" opacity="0.9" />
        {/* 四个趾垫 */}
        <ellipse cx="14" cy="18" rx="4.5" ry="5" fill="currentColor" opacity="0.9" />
        <ellipse cx="34" cy="18" rx="4.5" ry="5" fill="currentColor" opacity="0.9" />
        <ellipse cx="20" cy="13" rx="4" ry="5" fill="currentColor" opacity="0.9" />
        <ellipse cx="28" cy="13" rx="4" ry="5" fill="currentColor" opacity="0.9" />
      </g>
    </svg>
  )
}

/** 心跳线动画 SVG */
function HeartbeatSpinner({ size, colorClass }: { size: number; colorClass: string }) {
  return (
    <svg
      width={size}
      height={size}
      viewBox="0 0 48 48"
      fill="none"
      xmlns="http://www.w3.org/2000/svg"
    >
      {/* 心跳线路径 */}
      <path
        className={colorClass}
        d="M4 24h6l4-10 6 28 4-18h6"
        stroke="currentColor"
        strokeWidth="2.5"
        strokeLinecap="round"
        strokeLinejoin="round"
        fill="none"
        strokeDasharray="60"
        strokeDashoffset="60"
        style={{
          animation: 'heartbeat-draw 1.6s ease-in-out infinite',
        }}
      />
      {/* 脉冲点 */}
      <circle
        cx="24"
        cy="24"
        r="2"
        fill="currentColor"
        className={colorClass}
        style={{
          animation: 'heartbeat-pulse 1.6s ease-in-out infinite',
        }}
      />
    </svg>
  )
}

/** DNA 双螺旋动画 SVG */
function DnaSpinner({ size, colorClass }: { size: number; colorClass: string }) {
  return (
    <svg
      width={size}
      height={size}
      viewBox="0 0 48 48"
      fill="none"
      xmlns="http://www.w3.org/2000/svg"
    >
      {/* 左侧螺旋 */}
      <path
        className={colorClass}
        d="M18 4c-2 6 5 14 6 20-1 6-8 14-6 20"
        stroke="currentColor"
        strokeWidth="2"
        strokeLinecap="round"
        fill="none"
        opacity="0.6"
        style={{ animation: 'dna-wave 2s ease-in-out infinite' }}
      />
      {/* 右侧螺旋（相位偏移） */}
      <path
        className={colorClass}
        d="M30 4c2 6-5 14-6 20 1 6 8 14 6 20"
        stroke="currentColor"
        strokeWidth="2"
        strokeLinecap="round"
        fill="none"
        opacity="0.6"
        style={{ animation: 'dna-wave 2s ease-in-out 0.5s infinite' }}
      />
      {/* 横杠 */}
      <line x1="20" y1="12" x2="28" y2="12" stroke="currentColor" strokeWidth="1.5" className={colorClass} opacity="0.5" style={{ animation: 'dna-bar 2s ease-in-out infinite' }} />
      <line x1="18" y1="22" x2="30" y2="22" stroke="currentColor" strokeWidth="1.5" className={colorClass} opacity="0.5" style={{ animation: 'dna-bar 2s ease-in-out 0.3s infinite' }} />
      <line x1="18" y1="32" x2="30" y2="32" stroke="currentColor" strokeWidth="1.5" className={colorClass} opacity="0.5" style={{ animation: 'dna-bar 2s ease-in-out 0.6s infinite' }} />
    </svg>
  )
}

/** 默认圆形旋转器 */
function DefaultSpinner({ size, colorClass }: { size: number; colorClass: string }) {
  const borderWidth = size <= 24 ? 3 : 4
  return (
    <div
      className={`rounded-full animate-spin border-gray-200 ${colorClass}`}
      style={{
        width: size,
        height: size,
        borderWidth,
        borderTopColor: 'currentColor',
      }}
      role="presentation"
    />
  )
}

export default function LoadingSpinner({
  size = 'md',
  variant = 'paw',
  label,
  className = '',
  colorClass = 'text-medical-600',
}: LoadingSpinnerProps) {
  const { t } = useTranslation()
  const pxSize = SIZE_MAP[size]

  const renderSpinner = () => {
    switch (variant) {
      case 'paw':
        return <PawSpinner size={pxSize} colorClass={colorClass} />
      case 'heartbeat':
        return <HeartbeatSpinner size={pxSize} colorClass={colorClass} />
      case 'dna':
        return <DnaSpinner size={pxSize} colorClass={colorClass} />
      case 'spinner':
      default:
        return <DefaultSpinner size={pxSize} colorClass={colorClass} />
    }
  }

  return (
    <div
      className={`inline-flex flex-col items-center justify-center gap-2 ${className}`}
      role="status"
      aria-label={label || undefined}
    >
      {renderSpinner()}
      {label && (
        <span className="text-xs text-gray-400 font-medium">{label}</span>
      )}
      {!label && (
        <span className="sr-only">{t('common.loading')}</span>
      )}
    </div>
  )
}

/**
 * 全屏加载覆盖层
 * 用于页面级加载状态
 */
export function LoadingOverlay({
  message = '加载中...',
  variant = 'paw' as SpinnerVariant,
}: {
  message?: string
  variant?: SpinnerVariant
}) {
  return (
    <div
      className="fixed inset-0 z-[9998] flex items-center justify-center bg-white/60 backdrop-blur-sm"
      role="alert"
      aria-busy="true"
    >
      <LoadingSpinner size="lg" variant={variant} label={message} />
    </div>
  )
}