'use client';

import { useEffect, useRef, useState } from 'react';
import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';
import { Button } from '@/components/ui/button';
import { ToggleGroup, ToggleGroupItem } from '@/components/ui/toggle-group';
import { Play, Pause, RotateCcw, Square, Circle, Type } from 'lucide-react';
import { buildCSS } from '@/lib/animate/cssBuilder';
import type { AnimationConfig, PreviewElement } from '@/types/animate';

interface Props {
  config: AnimationConfig;
  element: PreviewElement;
  onElementChange: (e: PreviewElement) => void;
}

type AnimState = 'playing' | 'paused' | 'ended';

const SPEEDS: { label: string; value: string }[] = [
  { label: '0.25×', value: '0.25' },
  { label: '0.5×', value: '0.5' },
  { label: '1×', value: '1' },
  { label: '2×', value: '2' },
];

export function AnimationPreview({ config, element, onElementChange }: Props) {
  const styleRef = useRef<HTMLStyleElement | null>(null);
  const [restartKey, setRestartKey] = useState(0);
  const [animState, setAnimState] = useState<AnimState>('playing');
  const [speed, setSpeed] = useState('1');

  // Inject @keyframes CSS into document head
  useEffect(() => {
    if (!styleRef.current) {
      styleRef.current = document.createElement('style');
      styleRef.current.id = 'kit-animate-preview';
      document.head.appendChild(styleRef.current);
    }
    styleRef.current.textContent = buildCSS(config);
    // Restart preview whenever config changes so changes are immediately visible
    setAnimState('playing');
    setRestartKey((k) => k + 1);
  }, [config]);

  // Cleanup on unmount
  useEffect(() => {
    return () => { styleRef.current?.remove(); };
  }, []);

  const restart = () => {
    setAnimState('playing');
    setRestartKey((k) => k + 1);
  };

  const handlePlay = () => {
    if (animState === 'ended') {
      // Animation finished — restart it
      restart();
    } else {
      setAnimState('playing');
    }
  };

  const scaledDuration = Math.round(config.duration / Number(speed));
  const isInfinite = config.iterationCount === 'infinite';

  return (
    <Card className="h-full flex flex-col">
      <CardHeader className="flex flex-row items-center justify-between space-y-0">
        <CardTitle>Preview</CardTitle>
        <ToggleGroup type="single" value={speed} onValueChange={(v) => v && setSpeed(v)} variant="outline" size="sm">
          {SPEEDS.map((s) => (
            <ToggleGroupItem key={s.value} value={s.value} className="h-6 px-1.5 min-w-0 text-[10px]">
              {s.label}
            </ToggleGroupItem>
          ))}
        </ToggleGroup>
      </CardHeader>
      <CardContent className="flex-1 flex flex-col gap-4">
        {/* Preview canvas */}
        <div className="flex-1 min-h-52 flex items-center justify-center rounded-xl bg-gradient-to-br from-muted/20 to-muted/5 border border-border relative overflow-hidden">
          {/* Grid overlay */}
          <div
            className="absolute inset-0 opacity-5 pointer-events-none"
            style={{
              backgroundImage: 'linear-gradient(var(--border) 1px, transparent 1px), linear-gradient(90deg, var(--border) 1px, transparent 1px)',
              backgroundSize: '32px 32px',
            }}
          />

          {/* Animated element */}
          <div
            key={restartKey}
            className="animated relative z-10"
            style={{
              animationDuration: `${scaledDuration}ms`,
              animationPlayState: animState === 'paused' ? 'paused' : 'running',
            }}
            onAnimationEnd={() => !isInfinite && setAnimState('ended')}
          >
            {element === 'box' && (
              <div className="w-20 h-20 rounded-xl bg-gradient-to-br from-violet-500 to-purple-600 shadow-lg shadow-purple-500/30" />
            )}
            {element === 'circle' && (
              <div className="w-20 h-20 rounded-full bg-gradient-to-br from-cyan-400 to-violet-500 shadow-lg shadow-cyan-500/30" />
            )}
            {element === 'text' && (
              <span className="text-4xl font-bold bg-gradient-to-r from-violet-400 via-pink-400 to-cyan-400 bg-clip-text text-transparent select-none">
                Hello
              </span>
            )}
          </div>
        </div>

        {/* Controls */}
        <div className="flex items-center justify-between gap-3">
          <ToggleGroup type="single" value={element} onValueChange={(v) => v && onElementChange(v as PreviewElement)} variant="outline" size="sm">
            <ToggleGroupItem value="box" className="h-6 px-1.5 min-w-0" title="Box">
              <Square className="h-3 w-3" />
            </ToggleGroupItem>
            <ToggleGroupItem value="circle" className="h-6 px-1.5 min-w-0" title="Circle">
              <Circle className="h-3 w-3" />
            </ToggleGroupItem>
            <ToggleGroupItem value="text" className="h-6 px-1.5 min-w-0" title="Text">
              <Type className="h-3 w-3" />
            </ToggleGroupItem>
          </ToggleGroup>

          <div className="flex items-center gap-1.5">
            <Button
              size="icon-xs"
              variant="outline"
              onClick={handlePlay}
              disabled={animState === 'playing'}
              title={animState === 'ended' ? 'Replay' : 'Play'}
            >
              <Play className="h-3 w-3" />
            </Button>
            <Button
              size="icon-xs"
              variant="outline"
              onClick={() => setAnimState('paused')}
              disabled={animState !== 'playing'}
              title="Pause"
            >
              <Pause className="h-3 w-3" />
            </Button>
            <Button
              size="icon-xs"
              variant="outline"
              onClick={restart}
              title="Restart"
            >
              <RotateCcw className="h-3 w-3" />
            </Button>
          </div>
        </div>
      </CardContent>
    </Card>
  );
}