// Clock simulation engine — uses real timestamps for consistent timing
import { state } from './state.js';
import { evaluateAll } from './gates.js';
import { forceRecordSample } from './waveform.js';

let lastTickTime = 0;
let animFrameId = null;

function simLoop(now) {
    if (!state.simRunning) return;

    // Fire ticks that are due based on real elapsed time
    while (now - lastTickTime >= state.simSpeed) {
        lastTickTime += state.simSpeed;

        // Toggle all CLOCK gates
        state.gates.forEach(g => {
            if (g.type === 'CLOCK') {
                g.value = g.value ? 0 : 1;
            }
        });
        evaluateAll();
        if (state.recording && state.waveformVisible) {
            forceRecordSample();
        }
    }

    animFrameId = requestAnimationFrame(simLoop);
}

export function startSim() {
    if (state.simRunning) return;
    const hasClocks = state.gates.some(g => g.type === 'CLOCK');
    if (!hasClocks) return;

    state.simRunning = true;

    // Auto-open waveform panel
    if (!state.waveformVisible) {
        state.waveformVisible = true;
        document.getElementById('waveform-panel').classList.add('visible');
        document.getElementById('sim-btn').classList.add('active');
        window.dispatchEvent(new Event('resize'));
    }

    lastTickTime = performance.now();
    animFrameId = requestAnimationFrame(simLoop);
    updateSimUI();
}

export function stopSim() {
    state.simRunning = false;
    if (animFrameId) cancelAnimationFrame(animFrameId);
    animFrameId = null;
    updateSimUI();
}

export function updateSimUI() {
    const btn = document.getElementById('sim-run-btn');
    if (state.simRunning) {
        btn.textContent = '⏹ Stop';
        btn.classList.add('active');
    } else {
        btn.textContent = '▶ Run';
        btn.classList.remove('active');
    }
    document.getElementById('sim-speed-label').textContent = `${state.simSpeed}ms`;
}

export function adjustSpeed(delta) {
    const wasRunning = state.simRunning;
    state.simSpeed = Math.max(50, Math.min(2000, state.simSpeed + delta));
    // No need to restart — the loop reads simSpeed dynamically
    updateSimUI();
}