#include "enemies.h"
#include "renderer.h"
#include <math.h>   // för fmod()


GameObject heart[100], coin[100], alien[30], apples[100];
static void updateEnemies(GameObject* this);
static void renderEnemies(GameObject* this);

static void init(GameObject* pObj, GfxObject* pGfx, int x, int y, float startFrame, float frameSpeed, int numFrames)
{
    pObj->gfxObj = *pGfx;
    pObj->gfxObj.outputWidth  = 100;
    pObj->gfxObj.outputHeight = 100;
    pObj->pos.x = x;
    pObj->pos.y = y;
    pObj->speed = 0;
    pObj->angle = 0;               // unused
    pObj->angleSpeed = 0;          // unused
    pObj->scale = 1.0f;
    pObj->scaleSpeed = 0;          // unused
    pObj->update = updateEnemies;
    pObj->render = renderEnemies;
    pObj->frame = startFrame;
    pObj->frameSpeed = frameSpeed;
    pObj->numFrames = numFrames;
}

void createApple()
{
    static GfxObject gfx;
    static bool bFirstTime = true;
    if(bFirstTime) {
        bFirstTime = false;
        gfx = createGfxObject(  "../apples25st.png" );
    }
    init(&apples[0], &gfx, 100, 100, 0, 0.5f, 25);
    gameObjects[nGameObjects++] = &apples[0];
}

void createHearts()
{
    static GfxObject gfxHeart;
    static bool bFirstTime = true;
    
    // It is unnecesary to load the heart image for every instance. Just do it once:
    if(bFirstTime)
    {
        bFirstTime = false;
        // Create a GfxObject for the heart image
        gfxHeart = createGfxObject(  "../fireheart_new.png" );
        //gfxHeart = createGfxObject(  "../explosion50st.png" );
    }
        
    init(&heart[0], &gfxHeart, 100, 100, 0, 0.5f, 10);
    init(&heart[1], &gfxHeart, 200, 100, 3, 0.5f, 10);
    init(&heart[2], &gfxHeart, 300, 100, 6, 0.5f, 10);
    gameObjects[nGameObjects++] = &heart[0];
    gameObjects[nGameObjects++] = &heart[1];
    gameObjects[nGameObjects++] = &heart[2];
}

void createCoins()
{
    static GfxObject gfx;
    static bool bFirstTime = true;
    
    // It is unnecesary to load the heart image for every instance. Just do it once:
    if(bFirstTime)
    {
        bFirstTime = false;
        // Create a GfxObject for the heart image
        gfx = createGfxObject(  "../coinstrip40st.png" ); 
        //gfx = createGfxObject(  "../apples25st.png" ); 
        //gfx = createGfxObject(  "../alienship.png" );        
    }
    
    float frameSpeed = 1.0f;
    init(&coin[0], &gfx, 400, 100,  0, frameSpeed, 40);
    init(&coin[1], &gfx, 500, 100, 10, frameSpeed, 40);
    init(&coin[2], &gfx, 600, 100, 20, frameSpeed, 40);
    init(&coin[3], &gfx, 700, 100, 30, frameSpeed, 40);
    gameObjects[nGameObjects++] = &coin[0];
    gameObjects[nGameObjects++] = &coin[1];
    gameObjects[nGameObjects++] = &coin[2];
    gameObjects[nGameObjects++] = &coin[3]; 
}

static void updateEnemies(GameObject* this)
{
    // update which frame in texture to show
    this->frame = fmod( (this->frame+this->frameSpeed), this->numFrames );   
    
    // update positions
    static int iter = 0; 
    int duration = 200;
    float ampl = 100.0f, t;

    iter++;
    
    // this frame
    int frame = iter + (this->pos.x) / 3.5f;
    t = (frame % duration) / (float)(duration-1); // t: 0 -> duration
    float current_y = ampl*( fabs(2.0f*(3*t*t - 2*t*t*t) -1)); // snott fr. uppg.3 v1.
    
    // previous frame
    t = ((frame-1) % duration) / (float)(duration-1); 
    float previous_y = ampl*( fabs(2.0f*(3*t*t - 2*t*t*t) -1)); 
    
    // Compute delta step in y-direction
    float delta_y = current_y - previous_y;
    
    this->pos.y += delta_y;
}

static void renderEnemies(GameObject* this)
{
    if(this->status != DEAD)
    {
         // Render a sub frame to screen
        // Here, we know that the heart image is a sprite sheet with 10 frames
        // simply outlined next to each other in the x-direction.
        // Thus, the x-coordinate for the current frame is easy to compute:
        int w = this->gfxObj.textureWidth / this->numFrames;
        int x = w * (int)(this->frame);

        SDL_Rect srcRect = { x, 0, w, this->gfxObj.textureHeight }; // select the frame image
        
        renderGfxSubFrame(&this->gfxObj, this->pos.x, this->pos.y, this->angle, this->scale, srcRect );       
    }
}