import { useState, useRef, useEffect, KeyboardEvent } from 'react';
import { Input } from '@/Components/ui/input';
import { Label } from '@/Components/ui/label';
import { Switch } from '@/Components/ui/switch';
import { RefreshCcw, Scan, Zap } from 'lucide-react';
import { cn } from '@/lib/utils';

interface ScannerInputProps {
    onScan: (code: string, mode: 'continuous' | 'single') => void;
    className?: string;
    placeholder?: string;
}

export default function ScannerInput({ onScan, className, placeholder = "點擊此處並掃描..." }: ScannerInputProps) {
    const [code, setCode] = useState('');
    const [isContinuous, setIsContinuous] = useState(true);
    const [lastAction, setLastAction] = useState<{ message: string; type: 'success' | 'info' | 'error'; time: number } | null>(null);
    const [isFlashing, setIsFlashing] = useState(false);
    const inputRef = useRef<HTMLInputElement>(null);

    // Focus input on mount
    useEffect(() => {
        if (inputRef.current) {
            inputRef.current.focus();
        }
    }, []);

    // Audio context for beep sound
    const playBeep = (type: 'success' | 'error' = 'success') => {
        try {
            const AudioContext = window.AudioContext || (window as any).webkitAudioContext;
            if (!AudioContext) return;

            const ctx = new AudioContext();
            const oscillator = ctx.createOscillator();
            const gainNode = ctx.createGain();

            oscillator.connect(gainNode);
            gainNode.connect(ctx.destination);

            if (type === 'success') {
                oscillator.type = 'sine';
                oscillator.frequency.setValueAtTime(880, ctx.currentTime); // A5
                oscillator.frequency.exponentialRampToValueAtTime(440, ctx.currentTime + 0.1);
                gainNode.gain.setValueAtTime(0.1, ctx.currentTime);
                gainNode.gain.exponentialRampToValueAtTime(0.01, ctx.currentTime + 0.1);
                oscillator.start();
                oscillator.stop(ctx.currentTime + 0.1);
            } else {
                oscillator.type = 'sawtooth';
                oscillator.frequency.setValueAtTime(110, ctx.currentTime); // Low buzz
                gainNode.gain.setValueAtTime(0.2, ctx.currentTime);
                gainNode.gain.exponentialRampToValueAtTime(0.01, ctx.currentTime + 0.2);
                oscillator.start();
                oscillator.stop(ctx.currentTime + 0.2);
            }
        } catch (e) {
            console.error('Audio playback failed', e);
        }
    };

    const handleKeyDown = (e: KeyboardEvent<HTMLInputElement>) => {
        if (e.key === 'Enter') {
            e.preventDefault();
            if (code.trim()) {
                handleScanSubmit(code.trim());
            }
        }
    };

    const handleScanSubmit = (scannedCode: string) => {
        // Trigger parent callback
        onScan(scannedCode, isContinuous ? 'continuous' : 'single');

        // UI Feedback
        playBeep('success');
        setIsFlashing(true);
        setTimeout(() => setIsFlashing(false), 300);

        // Show last action tip
        setLastAction({
            message: `已掃描: ${scannedCode}`,
            type: 'success',
            time: Date.now()
        });

        // Clear input and focus
        setCode('');
    };

    // Public method to set last action message from parent (if needed for more context like product name)
    // For now we just use internal state

    return (
        <div className={cn("bg-white p-4 rounded-xl border-2 shadow-sm transition-all relative overflow-hidden", isFlashing ? "border-green-500 bg-green-50" : "border-primary/20", className)}>

            {/* Background flashy effect */}
            <div className={cn("absolute inset-0 bg-green-400/20 transition-opacity duration-300 pointer-events-none", isFlashing ? "opacity-100" : "opacity-0")} />

            <div className="flex flex-col md:flex-row gap-4 items-center justify-between relative z-10">

                {/* Left: Input Area */}
                <div className="flex-1 w-full relative">
                    <Scan className="absolute left-3 top-1/2 -translate-y-1/2 text-gray-400 h-5 w-5" />
                    <Input
                        ref={inputRef}
                        value={code}
                        onChange={(e) => setCode(e.target.value)}
                        onKeyDown={handleKeyDown}
                        placeholder={placeholder}
                        className="pl-10 h-12 text-lg font-mono border-gray-300 focus:border-primary focus:ring-primary/20"
                    />
                    {/* Continuous Mode Badge */}
                    <div className="absolute right-2 top-1/2 -translate-y-1/2 flex items-center gap-2">
                        {isContinuous && (
                            <div className="bg-primary/10 text-primary text-xs font-bold px-2 py-1 rounded-md flex items-center gap-1">
                                <Zap className="h-3 w-3 fill-primary" />
                                連續模式
                            </div>
                        )}
                    </div>
                </div>

                {/* Right: Controls & Status */}
                <div className="flex items-center gap-6 w-full md:w-auto justify-between md:justify-end">

                    {/* Last Action Display */}
                    <div className="flex-1 md:flex-none text-right min-h-[40px] flex flex-col justify-center">
                        {lastAction && (Date.now() - lastAction.time < 5000) ? (
                            <div className="animate-in fade-in slide-in-from-right-4 duration-300">
                                <span className="text-sm font-bold text-gray-800 block">{lastAction.message}</span>
                                {isContinuous && <span className="text-xs text-green-600 font-bold block">自動加總 (+1)</span>}
                            </div>
                        ) : (
                            <span className="text-gray-400 text-sm">等待掃描...</span>
                        )}
                    </div>

                    <div className="h-8 w-px bg-gray-200 hidden md:block"></div>

                    {/* Toggle */}
                    <div className="flex items-center gap-2">
                        <Label htmlFor="continuous-mode" className={cn("text-sm font-bold cursor-pointer select-none", isContinuous ? "text-primary" : "text-gray-500")}>
                            連續加總
                        </Label>
                        <Switch
                            id="continuous-mode"
                            checked={isContinuous}
                            onCheckedChange={setIsContinuous}
                        />
                    </div>
                </div>
            </div>

            <div className="mt-2 flex items-center gap-2 text-xs text-gray-400 px-1">
                <RefreshCcw className="h-3 w-3" />
                <span>提示：開啟連續模式時，掃描相同商品會自動將數量 +1；關閉則會視為新批號輸入。</span>
            </div>
        </div>
    );
}