frontend/src/components/TopNavBar.jsx

import React from 'react';
import { useApp } from '../context/AppContext';

const TopNavBar = () => {
    const { sessionData, isConnected, sendCommand } = useApp();
    
    const status = sessionData?.status || 'STANDBY';
    const isRunning = sessionData?.active && status !== 'COMPLETED';
    
    const isStandby = status === 'STANDBY' || status === 'READY';
    
    return (
        <header className="fixed top-0 w-full z-50 flex justify-between items-center px-6 h-16 bg-surface/60 backdrop-blur-xl border-b border-primary/10 shadow-[0_0_40px_rgba(0,212,255,0.04)]">
            <div className="flex items-center gap-8">
                <span className="text-2xl font-black tracking-tighter text-primary font-headline">NEXUS</span>
                <div className="h-8 w-px bg-outline-variant/20 hidden md:block"></div>
                <div className="hidden md:flex flex-col">
                    <span className="text-[10px] font-mono text-outline-variant tracking-widest uppercase">System Status</span>
                    <div className="text-sm font-mono text-tertiary">{status}</div>
                </div>
            </div>

            <div className="flex items-center gap-6">
                <div className="flex gap-2">
                    {/* START - clickable when standby */}
                    <button
                        onClick={() => sendCommand({ action: 'start' })}
                        disabled={isRunning}
                        className={`flex items-center gap-2 px-4 py-1.5 rounded-full border text-xs font-bold transition-all ${isRunning 
                            ? 'bg-surface-container text-slate-600 border-slate-700 cursor-not-allowed' 
                            : 'bg-tertiary/10 border-tertiary/20 text-tertiary hover:bg-tertiary/20 active:scale-95'}`}
                    >
                        <span className="material-symbols-outlined text-sm">play_arrow</span> START
                    </button>

                    {/* PAUSE/RESUME - clickable when running */}
                    <button
                        onClick={() => sendCommand({ action: 'pause' })}
                        disabled={!isRunning}
                        className={`flex items-center gap-2 px-4 py-1.5 rounded-full border text-xs font-bold transition-all ${!isRunning 
                            ? 'bg-surface-container text-slate-600 border-slate-700 cursor-not-allowed' 
                            : status === 'PAUSED'
                                ? 'bg-secondary text-surface border-secondary active:scale-95' 
                                : 'bg-secondary/10 border-secondary/20 text-secondary hover:bg-secondary/20 active:scale-95'}`}
                    >
                        <span className="material-symbols-outlined text-sm">{status === 'PAUSED' ? 'play_arrow' : 'pause'}</span>
                        {status === 'PAUSED' ? 'RESUME' : 'PAUSE'}
                    </button>

                    {/* FORCE END - clickable when running */}
                    <button
                        onClick={() => sendCommand({ action: 'force_end' })}
                        disabled={!isRunning}
                        className={`flex items-center gap-2 px-4 py-1.5 rounded-full border text-xs font-bold transition-all ${!isRunning 
                            ? 'bg-surface-container text-slate-600 border-slate-700 cursor-not-allowed' 
                            : 'bg-[#f59e0b]/10 border-[#f59e0b]/20 text-[#f59e0b] hover:bg-[#f59e0b]/20 active:scale-95'}`}
                    >
                        <span className="material-symbols-outlined text-sm">stop_circle</span> FORCE END
                    </button>

                    {/* RESET - always clickable */}
                    <button
                        onClick={() => sendCommand({ action: 'reset' })}
                        className="flex items-center gap-2 px-4 py-1.5 rounded-full bg-error/10 border border-error/20 text-error text-xs font-bold hover:bg-error/20 transition-all active:scale-95"
                    >
                        <span className="material-symbols-outlined text-sm">restart_alt</span> RESET
                    </button>
                </div>

                <div className="flex items-center gap-2 ml-4">
                    <div className={`w-2 h-2 rounded-full animate-pulse shadow-[0_0_8px_#66fa8c] ${isConnected ? 'bg-tertiary' : 'bg-error'}`}></div>
                    <span className={`text-[10px] font-mono font-bold tracking-widest uppercase ${isConnected ? 'text-tertiary' : 'text-error'}`}>
                        {isConnected ? 'CONNECTED' : 'DISCONNECTED'}
                    </span>
                </div>
            </div>
        </header>
    );
};

export default TopNavBar;