SandGame/physics.js

import { grid, cols, rows } from './state.js';
import { config } from './config.js';
import { move, swap } from './actions.js';
import { updateDirt } from './dirt.js';
import { updateWater } from './water.js';
import { updateAcid } from './acid.js';
import { updateSteam } from './steam.js';
import { updatePlant } from './plant.js';
import { updateFire } from './fire.js';
import { updateExplosive, explode } from './explosive.js';

export function spawnCell(x, y, type) {
    if (x >= 0 && x < cols && y >= 0 && y < rows) {
        const target = grid[x][y];
        
        // Manual Detonation
        if (target && target.type === 'explosive' && type === 'fire') {
            if (!config.time.paused) {
                explode(x, y);
            }
            return;
        }
        
        // Check if target is a fluid/gas that can be displaced
        const isDisplaceable = target && (target.type === 'water' || target.type === 'acid' || target.type === 'steam');
        
        if (!target || (isDisplaceable && type !== target.type)) {
            // If it's displaceable, try to push it aside
            if (isDisplaceable) {
                const neighbors = [[-1,0], [1,0], [0,-1], [0,1]];
                neighbors.sort(() => Math.random() - 0.5);

                for (let n of neighbors) {
                    const nx = x + n[0];
                    const ny = y + n[1];
                    if (nx >= 0 && nx < cols && ny >= 0 && ny < rows && !grid[nx][ny]) {
                        grid[nx][ny] = target; // Move fluid here
                        target.updated = true;
                        // Add Ripple Velocity
                        target.vx = (target.vx || 0) + n[0] * 2;
                        target.vy = (target.vy || 0) + n[1] * 2 - 1;
                        break;
                    }
                }
            }

            grid[x][y] = createCell(type);
        }
    }
}

function createCell(type) {
    const colors = {
        dirt: '#ffaa00',
        plant: '#228B22',
        water: '#0000FF',
        fire: '#FF5500',
        rock: '#808080',
        wood: '#8B4513',
        explosive: '#8B0000',
        acid: '#7FFF00',
        steam: '#E0FFFF'
    };
    return { type, color: colors[type] || '#FFF', updated: false };
}

export function update() {
    for (let x = 0; x < cols; x++) {
        for (let y = 0; y < rows; y++) {
            if (grid[x][y]) grid[x][y].updated = false;
        }
    }

    for (let y = rows - 1; y >= 0; y--) {
        for (let x = 0; x < cols; x++) {
            if (grid[x][y] && !grid[x][y].updated) {
                updateCell(x, y);
            }
        }
    }
}

function updateCell(x, y) {
    const cell = grid[x][y];
    cell.updated = true;

    // Physics for tossed particles (Explosions/Velocity)
    if (cell.vx || cell.vy) {
        applyVelocity(x, y, cell);
        // If velocity moved it, we might stop here or continue depending on logic.
        // For now, if it moved, we consider it updated for this frame.
        if (!grid[x][y] || grid[x][y] !== cell) return;
    }

    const type = cell.type;

    if (type === 'dirt') {
        updateDirt(x, y, cell);
    } else if (type === 'water') {
        updateWater(x, y, cell);
    } else if (type === 'fire') {
        updateFire(x, y, cell);
    } else if (type === 'steam') {
        updateSteam(x, y, cell);
    } else if (type === 'acid') {
        updateAcid(x, y, cell);
    } else if (type === 'plant') {
        updatePlant(x, y, cell);
    } else if (type === 'explosive') {
        updateExplosive(x, y, cell);
    }
}

function applyVelocity(x, y, cell) {
    cell.vx = cell.vx || 0;
    cell.vy = cell.vy || 0;
    
    if (cell.type === 'steam') {
        cell.vy -= 0.1; // Steam rises
    } else {
        cell.vy += config.global.gravity;
    }
    cell.vx *= config.global.drag;
    cell.vy *= config.global.drag;
    
    let nextX = Math.round(x + cell.vx);
    let nextY = Math.round(y + cell.vy);
    
    // Bounce off walls
    if (nextX < 0 || nextX >= cols) {
        cell.vx *= -0.5;
        nextX = x;
    }
    if (nextY < 0 || nextY >= rows) {
        cell.vy *= -0.3;
        nextY = y;
    }
    
    if (nextX >= 0 && nextX < cols && nextY >= 0 && nextY < rows) {
        const neighbor = grid[nextX][nextY];
        if (!neighbor) {
            move(x, y, nextX, nextY);
        } else if (neighbor.type === 'steam') {
            swap(x, y, nextX, nextY);
        } else if (neighbor.type === 'water' || neighbor.type === 'dirt' || neighbor.type === 'acid') {
            // Collision with movable particles
            neighbor.vx = (neighbor.vx || 0) + cell.vx * 0.8;
            neighbor.vy = (neighbor.vy || 0) + cell.vy * 0.8;
            neighbor.vx += (Math.random() - 0.5); // Scatter
            neighbor.updated = true;
            cell.vx *= -0.4;
            cell.vy *= -0.4;
        } else {
            cell.vx *= -0.3;
            cell.vy *= -0.3;
        }
    }
}