let images = {};
let simulator = [];
let maxSpeed = 1;
let backgroundImage;
let worldScale;
let LEFT = [-1,0];

const entityTypes = Object.freeze({
    METERORITE_SMALL: "meteorite_small",
    METERORITE_LARGE: "meteorite_large",
    COMET: "comet",
});

var Settings = {
    windowWrap: true,
    physics: true,
    respawn: true,
    devMode: false,
    maxSpeed: 1,
    backgroundImage: "/media/Art/EmptySpace.png",
    entityCount: 50,
    emptyEntries: [],
    rarity: {
        "comet": .9,
        "meteorite_small": 500.0,
        "meteorite_large": 1000.0,
    },
    mass: {
        "comet": 1400.0,
        "meteorite_small": 500.0,
        "meteorite_large": 1000.0,
    },
}

function distance(entity1, entity2){
    return Math.sqrt(
        ((entity2.x-entity1.x)*(entity2.x-entity1.x)) +
        ((entity2.y-entity1.y)*(entity2.y-entity1.y))
    );
}

function getMass(type){
    switch (type){
        case entityTypes.COMET: return Settings.mass[entityTypes.COMET]
        case entityTypes.METERORITE_SMALL: return Settings.mass[entityTypes.METERORITE_SMALL];
        case entityTypes.METERORITE_LARGE: return Settings.mass[entityTypes.METERORITE_LARGE];
    }
}

function createEntity(x, y, vx, vy, ax, ay, rot, rotv, type, id=0, iframes=Math.floor(Math.random()*100)){ 
    if (Settings.emptyEntries.length > 1){
        var entryID = Settings.emptyEntries.pop();
        if (Settings.devMode) console.warn("Creating new enity from old", entryID);
        if (entryID <= simulator.length && entryID >= 0){
            entity = simulator[entryID];
            entity.x = x;
            entity.y = y;
            entity.vx = vx;
            entity.vy = vy;
            entity.ax = ax;
            entity.ay = ay;
            entity.rot = rot;
            entity.rotv = rotv;
            entity.iframes = 1000;
            entity.show = true;
            entity.type = type
        }else{
            if (Settings.devMode) console.error("Entry ID out of bounds", Settings.emptyEntries.length, id, entryID);
        }
    }else{
        simulator.push({
        x: x,
        y: y,
        ax: ax,
        ay: ay,
        vx: vx,
        vy: vy,
        rot: rot,
        rotv: rotv,
        mass: getMass(type),
        forcex: 0.0,
        forcey: 0.0,
        type: type,
            show: true,
            ueid: id,
            iframes: iframes
        });
    }
}


function getRandomType(){
    let rand = Math.random();
    if (rand > 0.955){
        console.log("Comet made");
        return entityTypes.COMET;
    }if(rand > 0.4){
        return entityTypes.METERORITE_SMALL;
    }else{
        return entityTypes.METERORITE_LARGE;
    }
}

function physicsUpdate(entity){
    if (entity.show){
    entity.vx += entity.ax;
    entity.vy += entity.ay;
    entity.x += entity.vx;
    entity.y += entity.vy;
    entity.rot += entity.rotv;
        if (entity.iframes > 0) entity.iframes -= 1;
        if (entity.iframes == 0) simulator.forEach((other_entity) =>{
            checkCollision(entity, other_entity);
        });
    }
}

function checkCollision(entity1, entity2){
    if (entity1.type == entityTypes.COMET && entity2.type == entityTypes.COMET){
        
    }else if (entity1.ueid != entity2.ueid 
        && entity1.show 
        && entity2.show){
        var dist = distance(entity1, entity2);
        if(dist < 15){
            if (Settings.devMode) {
                stroke('magenta');
                strokeWeight(5);  
                line(entity1.x,entity1.y, entity2.x, entity2.y);
                console.log("Collision at", entity1.x, entity1.y, entity1.iframes, entity2.x, entity2.y, dist);
            }
        Explode(entity1);
            Explode(entity2);
        }
    }
    }

function Explode(entity){
    if(entity.type == entityTypes.METERORITE_SMALL){
        entity.show = false;
        Settings.emptyEntries.push(entity.ueid);
    }if(entity.type == entityTypes.METERORITE_LARGE){
        entity.type = entityTypes.METERORITE_SMALL
        entity.iframes = 1000;
        createEntity(entity.x, entity.y, entity.vx + Math.random(), entity.vy + Math.random(), 0.0,0.0,0.0,0.0, entityTypes.METERORITE_SMALL, id=entity.ueid, iframes=1000);
    }

}

function Explode(entity){

}

function drawBackground(refImage){
    let w = windowWidth / refImage.width;
    let h = windowHeight / refImage.height;
    for (let iy = 0; iy <= h; iy++){
        for (let ix = 0; ix <= w; ix++){
            image(refImage, refImage.width * ix, refImage.height * iy);
        }
    }
}

function drawEntity(entity){
    push();
    imageMode(CENTER);
    translate(entity.x*(worldScale.value()/100), entity.y*(worldScale.value()/100), 0);
    if (entity.type == entityTypes.COMET){
        rotate((Math.atan2(entity.vx, entity.vy) - Math.atan2(-1,0)) * 180/Math.PI);

    }else{
        rotate(entity.rot);
    }
    image(images[entity.type], 0,0);
    pop();
}

function preload(){
    images[entityTypes.METERORITE_SMALL] = loadImage("/media/Art/meteorite_small_1.png");
    images[entityTypes.METERORITE_LARGE] = loadImage("/media/Art/Meteorite_Large_1_100.png");
    images[entityTypes.COMET] = loadImage("/media/Art/comet.png");
    //images["ship"] = loadImage("/media/Art/ship.png"); #Make Ship asset for game portion
    images["background"] = loadImage("/media/Art/EmptySpace.png");
}

function setup(){
    let canvas = createCanvas(windowWidth, windowHeight);
    background(255);
    describe("A space physics simulator");
    
    canvas.position(0,0);
    worldScale = createSlider();
    //Load Entities
    
    for(var i = 0; i <= entityCount; i+=1){
        createEntity(
            Math.floor(Math.random() * windowWidth), //X Location
            Math.floor(Math.random() * windowHeight), //Y Location 
            (Math.random() * maxSpeed * 2)-maxSpeed, //X Velocity
            (Math.random() * maxSpeed * 2)-maxSpeed, //Y Velocity
            0.0, //X Acceleration
            0.0, //Y Acceleration
            0.0, //Current Rotation
            (Math.random() * 2 *(Math.PI / rotationSpeed))-(Math.PI / rotationSpeed), //Rotation Velocity
            getRandomType(),
            id=i
        );
    }
}

function mouseClicked(){
    console.log(mouseX, mouseY);
    simulator.forEach((entity) =>{
        
    })
    console.log(worldScale.value());
}

function draw(){
    //background(images["background"]);
    //Draw Tiled Background
    drawBackground(images["background"]);

    for(let e = 1; e < simulator.length; e++){
        let entity = simulator[e]
        
        //Physics Update
        if (Settings.physics){
            physicsUpdate(entity)
        }

        //Window Wrap
        if (Settings.windowWrap){
            if (entity.x * (worldScale.value() /100) > windowWidth){
                entity.x = 0;
            }
            if (entity.x < 0){
                entity.x = windowWidth / (worldScale.value() /100);
            }
            if (entity.y * (worldScale.value() /100) > windowHeight){
                entity.y = 0;
            }
            if (entity.y < 0){
                entity.y = windowHeight / (worldScale.value() /100);
            }
        }
        //Draw Entity
        drawEntity(entity);
    }
}

function windowResized() {
    resizeCanvas(windowWidth, windowHeight);
}