import { canvas, resize, cursor, brushSize, setBrushSize } from './state.js';
import { setupUI, handleInput, setLastPos, updateBrushUI } from './ui.js';
import { update } from './physics.js';
import { draw } from './renderer.js';
import { loadSettings, config, saveSettings } from './config.js';

let updateAccumulator = 0;

export function stepOnce() {
    update();
    draw();
}

function init() {
    loadSettings();
    if (config.brush?.size) {
        setBrushSize(config.brush.size);
    }
    resize();
    window.addEventListener('resize', resize);
    setupUI();
    
    // Input Handling
    let isMouseDown = false;
    let isRightClick = false;

    canvas.addEventListener('contextmenu', (e) => e.preventDefault());

    canvas.addEventListener('mousedown', (e) => {
        isMouseDown = true;
        isRightClick = (e.button === 2);
        cursor.visible = true;
        cursor.x = e.clientX;
        cursor.y = e.clientY;
        handleInput(e, isRightClick ? 'eraser' : null);
    });

    window.addEventListener('mouseup', () => {
        isMouseDown = false;
        isRightClick = false;
        setLastPos(null);
    });

    canvas.addEventListener('mousemove', (e) => {
        cursor.visible = true;
        cursor.x = e.clientX;
        cursor.y = e.clientY;
        if (isMouseDown) {
            handleInput(e, isRightClick ? 'eraser' : null);
        }
    });

    canvas.addEventListener('mouseenter', () => {
        cursor.visible = true;
    });

    canvas.addEventListener('mouseleave', () => {
        cursor.visible = false;
        setLastPos(null);
    });

    // Mouse wheel to change brush size
    canvas.addEventListener('wheel', (e) => {
        e.preventDefault();
        const delta = e.deltaY < 0 ? 1 : -1;
        setBrushSize(brushSize + delta);
        config.brush.size = brushSize;
        saveSettings();
        updateBrushUI();
    }, { passive: false });

    // Touch Support
    canvas.addEventListener('touchstart', (e) => {
        isMouseDown = true;
        if (e.touches.length > 0) {
            cursor.visible = true;
            cursor.x = e.touches[0].clientX;
            cursor.y = e.touches[0].clientY;
        }
        handleInput(e);
        e.preventDefault();
    }, { passive: false });

    canvas.addEventListener('touchend', (e) => {
        if (e.touches.length === 0) {
            isMouseDown = false;
            cursor.visible = false;
            setLastPos(null);
        }
    });

    canvas.addEventListener('touchmove', (e) => {
        if (e.touches.length > 0) {
            cursor.visible = true;
            cursor.x = e.touches[0].clientX;
            cursor.y = e.touches[0].clientY;
        }
        if (isMouseDown) handleInput(e);
        e.preventDefault();
    }, { passive: false });

    // Keyboard Shortcuts
    window.addEventListener('keydown', (e) => {
        if (e.target.tagName === 'INPUT' || e.target.tagName === 'TEXTAREA') return;

        if (e.code === 'Space') {
            e.preventDefault();
            config.time.paused = !config.time.paused;
            saveSettings();
            const pauseBtn = document.getElementById('togglePause');
            if (pauseBtn) pauseBtn.textContent = config.time.paused ? '▶' : '⏸';
        } else if (e.code === 'KeyS' || e.code === 'Period') {
            if (config.time.paused) {
                stepOnce();
            }
        } else if (e.code === 'BracketLeft') {
            setBrushSize(brushSize - 1);
            config.brush.size = brushSize;
            saveSettings();
            updateBrushUI();
        } else if (e.code === 'BracketRight') {
            setBrushSize(brushSize + 1);
            config.brush.size = brushSize;
            saveSettings();
            updateBrushUI();
        }
    });

    gameLoop();
}

function gameLoop() {
    if (!config.time.paused) {
        updateAccumulator += config.time.speed;
        while (updateAccumulator >= 1) {
            update();
            updateAccumulator -= 1;
            if (updateAccumulator > 30) {
                updateAccumulator = 0;
                break;
            }
        }
    }
    draw();
    requestAnimationFrame(gameLoop);
}

init();