/* V12 Physics Module */
import { state } from './state.js';

// Gravity state (persistent)
let velocityX = 0;
let velocityY = 0;
let offsetX = 0;
let offsetY = 0;

/**
 * Apply gravity pull toward mouse position
 * Returns offset to apply to star position
 */
export function applyGravity(canvasWidth, canvasHeight) {
    if (!state.gravityEnabled) {
        // Reset when disabled
        velocityX *= 0.95;
        velocityY *= 0.95;
        offsetX *= 0.95;
        offsetY *= 0.95;
        return { x: offsetX, y: offsetY };
    }

    // Target position (mouse or center)
    const targetX = state.mouseX || 0;
    const targetY = state.mouseY || 0;

    // Calculate attraction force
    const dx = targetX - offsetX;
    const dy = targetY - offsetY;
    const distance = Math.sqrt(dx * dx + dy * dy);

    if (distance > 5) {
        const force = 0.02; // Gravity strength
        const ax = (dx / distance) * force;
        const ay = (dy / distance) * force;

        velocityX += ax;
        velocityY += ay;
    }

    // Apply friction
    velocityX *= 0.98;
    velocityY *= 0.98;

    // Update position
    offsetX += velocityX;
    offsetY += velocityY;

    return { x: offsetX, y: offsetY };
}

/**
 * Calculate orbital position around center
 */
export function calculateOrbit(time, radius = 100) {
    if (!state.orbitEnabled) return { x: 0, y: 0 };

    const speed = 0.001; // Orbit speed
    const angle = time * speed;

    return {
        x: Math.cos(angle) * radius,
        y: Math.sin(angle) * radius
    };
}

/**
 * Reset physics state
 */
export function resetPhysics() {
    velocityX = 0;
    velocityY = 0;
    offsetX = 0;
    offsetY = 0;
}