import { createTerminal } from './terminal.js';
import { createInputHandler } from './input.js';
import { Scene } from './scene.js';
import { LayerType } from './layer.js';  // Only need LayerType
import { mergeConfig, getConfig } from './config.js';
import { state } from './state.js';
import { Time } from './time.js';
import { Physics } from './physics.js';

function start(userConfig) {
    if (state.engineStarted) {
        console.error("Engine.start() called more than once!");
        return;
    }

    // Initialize config first
    mergeConfig(userConfig);
    state.engineStarted = true;

    // Create and setup canvas
    const canvas = document.createElement('canvas');
    document.body.appendChild(canvas);
    state.ctx = canvas.getContext('2d');

    // Create scene first
    state.scene = new Scene();
    state.scene.start();

    // Define and call resizeCanvas after scene creation
    const resizeCanvas = () => {
        state.canvasWidth = canvas.width = window.innerWidth;
        state.canvasHeight = canvas.height = window.innerHeight;
        // Now camera is available
        state.scene.camera.setViewport(state.canvasWidth, state.canvasHeight);
    };
    resizeCanvas();

    // Create input handler with canvas and scene
    state.inputHandler = createInputHandler(canvas, state.scene);

    // Create terminal last
    const terminalLayer = state.scene.getLayer(LayerType.TERMINAL);
    state.terminal = createTerminal(canvas, state.ctx, state.inputHandler);
    terminalLayer.addEntity(state.terminal);

    const config = getConfig();  // Get config at the start function level

    // Add resize listener
    window.addEventListener('resize', resizeCanvas);
}

export function run(userConfig) {
    state.currentConfig = userConfig;
    if (!state.engineStarted) {
        start(userConfig);
    }

    const config = getConfig();
    state.angularSpeed = config.initialAngularSpeed;
    state.physics = new Physics(config);

    // Game functions
    function Update(deltaTime) {
        // Clear the canvas
        state.ctx.clearRect(0, 0, state.canvasWidth, state.canvasHeight);

        // Update camera
        state.scene.camera.update(deltaTime);

        // Update scene (this will update entities)
        state.scene.update(deltaTime);

        // FPS calculation
        state.fps = Math.round(1 / deltaTime);

        // Draw scene (now includes debug layer)
        state.scene.draw(state.ctx);

        // Draw terminal text
        state.terminal.drawText();
    }

    function FixedUpdate(deltaTime) {
        state.physics.update(deltaTime);
    }

    // Game loop
    function gameLoop() {
        state.animationFrameId = requestAnimationFrame(gameLoop);

        Time.update();

        while (Time.accumulatedTime >= Time.fixedDeltaTime) {
            FixedUpdate(Time.fixedDeltaTime);
            Time.resetAccumulator();
        }

        Update(Time.deltaTime);
    }

    // Start the game loop
    gameLoop();
}