'use client';

import { useState } from 'react';
import { Button } from '@/components/ui/button';
import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card';
import { MathBlock } from '@/components/math/MathFormula';
import { Lightbulb, Eye, Sparkles } from 'lucide-react';
import { cn } from '@/lib/utils';

/**
 * Hint data interface
 */
export interface Hint {
  id: string;
  content: string;
  isMath?: boolean;
  cost?: number;
}

/**
 * HintSystem component props
 */
export interface HintSystemProps {
  /**
   * Array of hints
   */
  hints: Hint[];

  /**
   * Current points
   */
  currentPoints?: number;

  /**
   * Points penalty per hint
   */
  pointsPerHint?: number;

  /**
   * Revealed hint indices
   */
  revealedHints?: Set<number>;

  /**
   * On hint reveal callback
   */
  onRevealHint?: (index: number, cost: number) => void;

  /**
   * Additional CSS classes
   */
  className?: string;

  /**
   * Compact mode
   */
  compact?: boolean;
}

/**
 * HintSystem component - displays hints with point costs
 */
export function HintSystem({
  hints,
  currentPoints,
  pointsPerHint = 5,
  revealedHints = new Set<number>(),
  onRevealHint,
  className,
  compact = false,
}: HintSystemProps) {
  const [showAll] = useState(false);

  if (hints.length === 0) {
    return null;
  }

  const canAffordHint = (hintIndex: number) => {
    if (!currentPoints) return true;

    const alreadyRevealed = Array.from(revealedHints).filter((i) => i <= hintIndex).length;
    const cost = (alreadyRevealed + 1) * pointsPerHint;
    return currentPoints >= cost;
  };

  const getHintCost = (hintIndex: number) => {
    const alreadyRevealed = Array.from(revealedHints).filter((i) => i <= hintIndex).length;
    return (alreadyRevealed + 1) * pointsPerHint;
  };

  const handleRevealHint = (index: number) => {
    if (onRevealHint) {
      onRevealHint(index, getHintCost(index));
    }
  };

  const allRevealed = revealedHints.size === hints.length;
  const hasUnrevealed = hints.length > revealedHints.size;

  return (
    <Card className={cn('border-yellow-200 dark:border-yellow-800', className)}>
      <CardHeader className={compact ? 'pb-3' : undefined}>
        <div className="flex items-center justify-between">
          <div className="flex items-center gap-2">
            <Lightbulb className="h-5 w-5 text-yellow-600 dark:text-yellow-400" />
            <CardTitle className="text-lg">Hints</CardTitle>
          </div>

          {hasUnrevealed && !compact && (
            <div className="text-sm text-muted-foreground">
              {revealedHints.size}/{hints.length} revealed
            </div>
          )}
        </div>

        {!compact && (
          <CardDescription>
            {currentPoints !== undefined && (
              <span>Cost: {pointsPerHint} points per hint (progressive)</span>
            )}
            {currentPoints === undefined && <span>Click to reveal hints</span>}
          </CardDescription>
        )}
      </CardHeader>

      <CardContent className="space-y-3">
        {hints.map((hint, index) => {
          const isRevealed = revealedHints.has(index);
          const cost = getHintCost(index);
          const canAfford = canAffordHint(index);

          if (!showAll && !isRevealed && index > 0 && !revealedHints.has(index - 1)) {
            // Hide hints that are not yet available (sequential reveal)
            return null;
          }

          return (
            <div
              key={hint.id}
              className={cn(
                'rounded-lg border p-4 transition-all duration-300',
                isRevealed
                  ? 'bg-yellow-50 dark:bg-yellow-950 border-yellow-200 dark:border-yellow-800'
                  : 'bg-muted border-muted-foreground/20',
                isRevealed && 'animate-in fade-in slide-in-from-bottom-2 duration-300'
              )}
            >
              <div className="flex items-start gap-3">
                <div
                  className={cn(
                    'flex-shrink-0 w-6 h-6 rounded-full flex items-center justify-center text-xs font-bold',
                    isRevealed
                      ? 'bg-yellow-200 dark:bg-yellow-800 text-yellow-800 dark:text-yellow-200'
                      : 'bg-muted-foreground/20 text-muted-foreground'
                  )}
                >
                  {index + 1}
                </div>

                <div className="flex-1 min-w-0">
                  {isRevealed ? (
                    <div className="animate-in fade-in duration-300 delay-100">
                        {hint.isMath ? (
                          <MathBlock formula={hint.content} />
                        ) : (
                          <p className="text-sm text-yellow-900 dark:text-yellow-100">
                            {hint.content}
                          </p>
                        )}

                        {hint.cost && (
                          <div className="mt-2 flex items-center gap-1 text-xs text-yellow-700 dark:text-yellow-300">
                            <Sparkles className="h-3 w-3" />
                            <span>Cost: {hint.cost} points</span>
                          </div>
                        )}
                      </div>
                    ) : (
                      <div className="space-y-2">
                        <p className="text-sm text-muted-foreground">
                          Hint #{index + 1} -{' '}
                          {currentPoints !== undefined ? (
                            canAfford ? (
                              <span className="text-foreground">Reveal for {cost} points</span>
                            ) : (
                              <span className="text-destructive">Need {cost - currentPoints} more points</span>
                            )
                          ) : (
                            <span className="text-foreground">Click to reveal</span>
                          )}
                        </p>

                        {onRevealHint && (
                          <Button
                            size="sm"
                            variant="outline"
                            onClick={() => handleRevealHint(index)}
                            disabled={!canAfford}
                            className="gap-1.5"
                          >
                            <Eye className="h-3.5 w-3.5" />
                            Reveal Hint
                          </Button>
                        )}
                      </div>
                    )}
                  </div>
                </div>
              </div>
            );
          })}

        {allRevealed && (
          <div className="text-center py-2 animate-in fade-in duration-300">
            <p className="text-sm text-muted-foreground">
              <Sparkles className="h-4 w-4 inline-block mr-1" />
              All hints revealed!
            </p>
          </div>
        )}
      </CardContent>
    </Card>
  );
}

/**
 * Compact hint button for inline display
 */
export interface HintButtonProps {
  hintCount: number;
  revealedCount: number;
  onClick?: () => void;
  className?: string;
}

export function HintButton({ hintCount, revealedCount, onClick, className }: HintButtonProps) {
  return (
    <Button
      variant="outline"
      size="sm"
      onClick={onClick}
      className={cn('gap-2', className)}
    >
      <Lightbulb className="h-4 w-4" />
      <span>Hint</span>
      <span className="text-xs text-muted-foreground">
        ({revealedCount}/{hintCount})
      </span>
    </Button>
  );
}