/**
 * Skeleton - Loading skeleton components for web
 *
 * Components:
 * - Skeleton: Basic skeleton element
 * - SkeletonCard: Card-style skeleton
 * - SkeletonList: List of skeleton items
 * - SkeletonText: Text skeleton with multiple lines
 * - SkeletonAvatar: Avatar/profile picture skeleton
 *
 * Features:
 * - Animated shimmer effect
 * - Multiple variants and sizes
 * - Composable building blocks
 * - Tailwind CSS styling
 *
 * @example
 * ```tsx
 * if (isLoading) {
 *   return <SkeletonCard />;
 * }
 * ```
 */

import { cn } from '@/lib/utils';

/**
 * Skeleton - Base skeleton component with shimmer animation
 */
interface SkeletonProps {
  className?: string;
  variant?: 'rectangular' | 'circular' | 'text';
}

export function Skeleton({
  className,
  variant = 'rectangular',
}: SkeletonProps) {
  const variantClasses = {
    rectangular: 'rounded',
    circular: 'rounded-full',
    text: 'rounded h-4',
  };

  return (
    <div
      className={cn(
        'animate-pulse bg-slate-200',
        variantClasses[variant],
        className
      )}
      aria-hidden="true"
    />
  );
}

/**
 * SkeletonAvatar - Avatar skeleton with circular shape
 *
 * @example
 * ```tsx
 * <SkeletonAvatar size="lg" />
 * ```
 */
interface SkeletonAvatarProps {
  size?: 'sm' | 'md' | 'lg' | 'xl';
  className?: string;
}

const avatarSizes = {
  sm: 'h-8 w-8',
  md: 'h-10 w-10',
  lg: 'h-12 w-12',
  xl: 'h-16 w-16',
};

export function SkeletonAvatar({
  size = 'md',
  className,
}: SkeletonAvatarProps) {
  return (
    <Skeleton
      variant="circular"
      className={cn(avatarSizes[size], className)}
    />
  );
}

/**
 * SkeletonText - Multi-line text skeleton
 *
 * @example
 * ```tsx
 * <SkeletonText lines={3} />
 * ```
 */
interface SkeletonTextProps {
  lines?: number;
  className?: string;
}

export function SkeletonText({ lines = 3, className }: SkeletonTextProps) {
  return (
    <div className={cn('space-y-2', className)}>
      {Array.from({ length: lines }).map((_, i) => (
        <Skeleton
          key={i}
          variant="text"
          className={cn(
            'h-4',
            i === lines - 1 && 'w-3/4' // Last line is shorter
          )}
        />
      ))}
    </div>
  );
}

/**
 * SkeletonCard - Card-style skeleton with header and content
 *
 * @example
 * ```tsx
 * {isLoading ? (
 *   <SkeletonCard />
 * ) : (
 *   <BeneficiaryCard data={data} />
 * )}
 * ```
 */
interface SkeletonCardProps {
  showAvatar?: boolean;
  lines?: number;
  className?: string;
}

export function SkeletonCard({
  showAvatar = true,
  lines = 3,
  className,
}: SkeletonCardProps) {
  return (
    <div
      className={cn(
        'rounded-lg border border-slate-200 bg-white p-6',
        className
      )}
    >
      <div className="flex items-start gap-4">
        {showAvatar && <SkeletonAvatar size="lg" />}
        <div className="flex-1 space-y-3">
          <Skeleton className="h-6 w-1/3" />
          <SkeletonText lines={lines} />
        </div>
      </div>
    </div>
  );
}

/**
 * SkeletonList - List of skeleton cards
 *
 * @example
 * ```tsx
 * {isLoading ? (
 *   <SkeletonList count={5} />
 * ) : (
 *   items.map(item => <ItemCard key={item.id} {...item} />)
 * )}
 * ```
 */
interface SkeletonListProps {
  count?: number;
  showAvatar?: boolean;
  className?: string;
}

export function SkeletonList({
  count = 3,
  showAvatar = true,
  className,
}: SkeletonListProps) {
  return (
    <div className={cn('space-y-4', className)}>
      {Array.from({ length: count }).map((_, i) => (
        <SkeletonCard key={i} showAvatar={showAvatar} />
      ))}
    </div>
  );
}

/**
 * SkeletonTable - Table skeleton with rows and columns
 *
 * @example
 * ```tsx
 * {isLoading ? (
 *   <SkeletonTable rows={5} columns={4} />
 * ) : (
 *   <DataTable data={data} />
 * )}
 * ```
 */
interface SkeletonTableProps {
  rows?: number;
  columns?: number;
  showHeader?: boolean;
  className?: string;
}

export function SkeletonTable({
  rows = 5,
  columns = 4,
  showHeader = true,
  className,
}: SkeletonTableProps) {
  return (
    <div className={cn('overflow-hidden rounded-lg border border-slate-200', className)}>
      {/* Header */}
      {showHeader && (
        <div className="flex gap-4 border-b border-slate-200 bg-slate-50 p-4">
          {Array.from({ length: columns }).map((_, i) => (
            <Skeleton key={i} className="h-4 flex-1" />
          ))}
        </div>
      )}

      {/* Rows */}
      <div className="divide-y divide-slate-200 bg-white">
        {Array.from({ length: rows }).map((_, rowIndex) => (
          <div key={rowIndex} className="flex gap-4 p-4">
            {Array.from({ length: columns }).map((_, colIndex) => (
              <Skeleton key={colIndex} className="h-4 flex-1" />
            ))}
          </div>
        ))}
      </div>
    </div>
  );
}

/**
 * SkeletonDashboard - Dashboard-style skeleton with multiple sections
 *
 * @example
 * ```tsx
 * {isLoading ? (
 *   <SkeletonDashboard />
 * ) : (
 *   <Dashboard data={data} />
 * )}
 * ```
 */
export function SkeletonDashboard() {
  return (
    <div className="space-y-6">
      {/* Header */}
      <div className="flex items-center justify-between">
        <Skeleton className="h-8 w-48" />
        <Skeleton className="h-10 w-32" />
      </div>

      {/* Stats grid */}
      <div className="grid gap-4 md:grid-cols-2 lg:grid-cols-4">
        {Array.from({ length: 4 }).map((_, i) => (
          <div key={i} className="rounded-lg border border-slate-200 bg-white p-6">
            <Skeleton className="mb-2 h-4 w-24" />
            <Skeleton className="h-8 w-16" />
          </div>
        ))}
      </div>

      {/* Content */}
      <div className="grid gap-6 lg:grid-cols-2">
        <div className="space-y-4">
          <Skeleton className="h-6 w-32" />
          <SkeletonCard />
          <SkeletonCard />
        </div>
        <div className="space-y-4">
          <Skeleton className="h-6 w-32" />
          <SkeletonCard />
          <SkeletonCard />
        </div>
      </div>
    </div>
  );
}

/**
 * SkeletonForm - Form skeleton with fields and button
 *
 * @example
 * ```tsx
 * {isLoading ? (
 *   <SkeletonForm fields={5} />
 * ) : (
 *   <BeneficiaryForm onSubmit={handleSubmit} />
 * )}
 * ```
 */
interface SkeletonFormProps {
  fields?: number;
  className?: string;
}

export function SkeletonForm({ fields = 3, className }: SkeletonFormProps) {
  return (
    <div className={cn('space-y-4', className)}>
      {Array.from({ length: fields }).map((_, i) => (
        <div key={i} className="space-y-2">
          <Skeleton className="h-4 w-24" />
          <Skeleton className="h-10 w-full" />
        </div>
      ))}
      <Skeleton className="h-10 w-full" />
    </div>
  );
}