#include <math.h>
#include "Vector3D.h"
#include "GameEngine.h"
#include "Control.h"

long tickCounter = 0;
long renderTickCounter = 0;

long tickSum = 0;
long renderTickSum = 0;

long tickTime = -1;
long renderTickTime = -1;

typedef struct GameField
{
    int id;
    float r;
    float g;
    float b;
    float a;
} GameField;

int amountGameFields = -1;
GameField* gameFields = NULL;

GLuint vbo = -1;
GLuint vba = -1;

int fieldSize = 0;
int quality = 0;
int vertices = 0;
GLsizeiptr size = 0;
GLfloat* data = NULL;

Vector3D oldCamera;
Vector3D camera;
float oldLengthAngle;
float lengthAngle;
float oldWidthAngle;
float widthAngle;

float mouseX = 0.0f;
float mouseY = 0.0f;

Vector3D front;
Vector3D back;
Vector3D right;
Vector3D left;
Vector3D up;
Vector3D down;

int selectedIndex = -1;
int selectedLayer = -1;

GameField* getGameField(int layer, int index)
{   
    if(layer == 0)
    {
        return &gameFields[0];
    }
    else if(layer == 1 + fieldSize)
    {
        return &gameFields[1];
    }
    
    index += (layer - 1) * fieldSize + 2;
    if(index < 2 || index >= amountGameFields)
    {
        return NULL;
    }
    return &gameFields[index];
}

float interpolate(float lag, float old, float new)
{
    return old + lag * (new - old);
}

void colorField(GameField* field)
{
    if(field->id)
    {
        field->r = 1.0f;
        field->g = 0.0f;
        field->b = 0.0f;
        field->a = 1.0f;
    }
    else
    {
        field->r = 1.0f;
        field->g = 1.0f;
        field->b = 1.0f;
        field->a = 1.0f;
    }
}

void generateSphere()
{
    int triangles = fieldSize * quality;
    int layers = (2 + fieldSize) * quality;
    
    if(gameFields == NULL)
    {
        amountGameFields = 2 + fieldSize * fieldSize;
        gameFields = malloc(sizeof(GameField) * amountGameFields);
        for(int i = 0; i < amountGameFields; i++)
        {
            gameFields[i].id = (rand() < RAND_MAX / 2) ? 1 : 0;
            colorField(&gameFields[i]);
        }
    }
    
    if(data == NULL)
    {
        vertices = triangles * layers * 3 * 2;
        size = sizeof(GLfloat) * 9 * vertices;
        data = malloc(size);
    }

    for(int l = 0; l < layers; l++)
    {
        float high1 = cos((M_PI * l) / layers);
        float high2 = cos((M_PI * (l + 1)) / layers);
        
        float texHigh1 = (l % quality) * (1.0f / quality);  
        float texHigh2 = texHigh1 + (1.0f / quality);  
        
        float r1 = sqrt(1 - high1 * high1);
        float r2 = sqrt(1 - high2 * high2);
        
        int flag = (l / quality) == 0;
        if(flag)
        {
            texHigh1 = 1 - texHigh1;
            texHigh2 = 1 - texHigh2;
        }
        flag |= (l / quality) >= fieldSize + 1;
        
        for(int i = 0; i < triangles; i++)
        {
            float first = 2 * M_PI * i / triangles;
            float second = 2 * M_PI * (i + 1) / triangles;

            int off = 27 * 2 * i + l * triangles * 27 * 2;
            
            float texWidth1 = (i % quality) * (1.0f / quality);  
            float texWidth2 = texWidth1 + (1.0f / quality);  
            
            float r = 0.0f;
            float g = 0.0f;
            float b = 0.0f;
            float a = 0.0f;
            
            GameField* field = getGameField(l / quality, i / quality);
            if(field != NULL)
            {
                r = field->r;
                g = field->g;
                b = field->b;
                a = field->a;
            }
            
            for(int j = 0; j < 54; j += 9)
            {
                data[3 + off + j] = r;
                data[4 + off + j] = g;
                data[5 + off + j] = b;
                data[6 + off + j] = a;
            }
            
            data[0 + off] = r2 * cos(first);
            data[1 + off] = high2;
            data[2 + off] = r2 * sin(first);
            
            data[9 + off] = r1 * cos(first);
            data[10 + off] = high1;
            data[11 + off] = r1 * sin(first);
            
            data[18 + off] = r1 * cos(second);
            data[19 + off] = high1;
            data[20 + off] = r1 * sin(second);
            
            if(flag)
            {
                data[7 + off] = texHigh2 * 0.5f;
                data[8 + off] = texHigh2 * 0.5f;

                data[16 + off] = texHigh1 * 0.5f;
                data[17 + off] = texHigh1 * 0.5f;

                data[25 + off] = texHigh1 * 0.5f;
                data[26 + off] = texHigh1 * 0.5f;
            }
            else
            {
                data[7 + off] = texWidth1;
                data[8 + off] = texHigh2;

                data[16 + off] = texWidth1;
                data[17 + off] = texHigh1;

                data[25 + off] = texWidth2;
                data[26 + off] = texHigh1;
            }

            data[27 + off] = r2 * cos(first);
            data[28 + off] = high2;
            data[29 + off] = r2 * sin(first);            

            data[36 + off] = r1 * cos(second);
            data[37 + off] = high1;
            data[38 + off] = r1 * sin(second);
            
            data[45 + off] = r2 * cos(second);
            data[46 + off] = high2;
            data[47 + off] = r2 * sin(second);
            
            if(flag)
            {
                data[34 + off] = texHigh2 * 0.5f;
                data[35 + off] = texHigh2 * 0.5f;

                data[43 + off] = texHigh1 * 0.5f;
                data[44 + off] = texHigh1 * 0.5f;

                data[52 + off] = texHigh2 * 0.5f;
                data[53 + off] = texHigh2 * 0.5f;
            }
            else
            {
                data[34 + off] = texWidth1;
                data[35 + off] = texHigh2;

                data[43 + off] = texWidth2;
                data[44 + off] = texHigh1;

                data[52 + off] = texWidth2;
                data[53 + off] = texHigh2;
            }
        }
    }

    glBufferData(GL_ARRAY_BUFFER, size, data, GL_STATIC_DRAW);
}

void updateProjection(float aspect, int program)
{
    float fovY = 60.0f;
    float nearClip = 0.1f;
    float farClip = 1000;
    
    float q = 1.0f / (float) tan((0.5f * fovY) * M_PI / 180.0f);
    float a = q / aspect;
    float b = (nearClip + farClip) / (nearClip - farClip);
    float c = (2.0f * nearClip * farClip) / (nearClip - farClip);

    GLfloat data[16];
    data[0] = a;
    data[1] = 0.0f;
    data[2] = 0.0f;
    data[3] = 0.0f;
    
    data[4] = 0.0f;
    data[5] = q;
    data[6] = 0.0f;
    data[7] = 0.0f;
    
    data[8] = 0.0f;
    data[9] = 0.0f;
    data[10] = b;
    data[11] = -1.0f;
    
    data[12] = 0.0f;
    data[13] = 0.0f;
    data[14] = c;
    data[15] = 0;
    
    GLint loc = glGetUniformLocation(program, "projMatrix");
    glUniformMatrix4fv(loc, 1, 0, data);
}

float chooseSmallerPositive(float a, float b)
{
    if(a < 0)
    {
        return b;
    }
    else if(b < 0 || b > a)
    {
        return a;
    }
    return b;
}

void updateView(int program, float lag)
{
    // front
    vectorSetAngles(&front, interpolate(lag, oldLengthAngle, lengthAngle), interpolate(lag, oldWidthAngle, widthAngle));
    
    // calculate selected tile
    float a = camera.x * camera.x + camera.y * camera.y + camera.z * camera.z - 1;
    float b = 2 * (camera.x * front.x + camera.y * front.y + camera.z * front.z);
    float c = front.x * front.x + front.y * front.y + front.z * front.z;

    float p = b / c;
    float q = a / c;

    float det = p * p * 0.25f - q;
    if(det >= 0)
    {
        float k = sqrt(det);
        k = chooseSmallerPositive(-0.5f * p + k, -0.5f * p - k);
        if(k >= 0)
        {
            Vector3D v;
            vectorSetTo(&v, &camera);
            vectorAddMul(&v, &front, k);

            selectedLayer = (asin(-v.y) + M_PI_2) * M_1_PI * (2 + fieldSize);
            if(selectedLayer == 2 + fieldSize)
            {
                selectedLayer = fieldSize + 1;
            }

            float tan = atan2(v.z, v.x) * M_1_PI * 0.5;
            tan += (tan < 0);
            selectedIndex = tan * fieldSize;
        }
    }

    // back
    vectorSetToInverse(&back, &front);

    // right
    vectorSetTo(&right, &front);
    vectorCross(&right, 0.0f, 1.0f, 0.0f);
    vectorNormalize(&right);
    
    // left
    vectorSetToInverse(&left, &right);

    // up
    vectorSetTo(&up, &front);
    vectorCrossWith(&up, &left);
    vectorNormalize(&up);
    
    // down
    vectorSetToInverse(&down, &up);

    GLfloat data[16];
    data[0] = right.x;
    data[1] = up.x;
    data[2] = back.x;
    data[3] = 0.0f;
    
    data[4] = right.y;
    data[5] = up.y;
    data[6] = back.y;
    data[7] = 0.0f;
    
    data[8] = right.z;
    data[9] = up.z;
    data[10] = back.z;
    data[11] = 0.0f;
    
    Vector3D interCam;
    vectorSetTo(&interCam, &oldCamera);
    vectorAddMul(&interCam, &camera, lag);
    vectorAddMul(&interCam, &oldCamera, -lag);
    
    data[12] = vectorDotInverse(&right, &interCam);
    data[13] = vectorDotInverse(&up, &interCam);
    data[14] = vectorDotInverse(&back, &interCam);
    data[15] = 1.0f;
    
    //printf("%f %f %f %f\n", data[0], data[4], data[8], data[12]);
    //printf("%f %f %f %f\n", data[1], data[5], data[9], data[13]);
    //printf("%f %f %f %f\n", data[2], data[6], data[10], data[14]);
    //printf("%f %f %f %f\n", data[3], data[7], data[11], data[15]);
    
    // front
    vectorSetAngles(&front, interpolate(lag, oldLengthAngle, lengthAngle), interpolate(lag, oldWidthAngle, widthAngle));
    front.y = 0;
    vectorNormalize(&front);

    // back
    vectorSetToInverse(&back, &front);

    // right
    vectorSetTo(&right, &front);
    vectorCross(&right, 0.0f, 1.0f, 0.0f);
    vectorNormalize(&right);
    
    // left
    vectorSetToInverse(&left, &right);

    // up
    vectorSet(&up, 0.0f, 1.0f, 0.0f);
    
    // down
    vectorSetToInverse(&down, &up);
    
    GLint loc = glGetUniformLocation(program, "viewMatrix");
    glUniformMatrix4fv(loc, 1, 0, data);
}

void init(int program)
{
    printf("Init\n");
    
    glGenBuffers(1, &vbo);
    glGenVertexArrays(1, &vba);
    
    glBindBuffer(GL_ARRAY_BUFFER, vbo);
    glBindVertexArray(vba);

    glVertexAttribPointer(0, 3, GL_FLOAT, 0, 36, (GLvoid*) 0);
    glEnableVertexAttribArray(0);

    glVertexAttribPointer(1, 4, GL_FLOAT, 0, 36, (GLvoid*) 12);
    glEnableVertexAttribArray(1);       
    
    glVertexAttribPointer(2, 2, GL_FLOAT, 0, 36, (GLvoid*) 28);
    glEnableVertexAttribArray(2);    
    
    generateSphere();
    
    vectorSet(&camera, 0.0f, 0.0f, -5.0f);
    lengthAngle = 0.0f;
    widthAngle = 0.0f;
    
    updateProjection(4.0f / 3.0f, program);
}

void invertField(int layer, int index)
{
    GameField* field = getGameField(layer, index);
    if(field != NULL)
    {
        field->id = 1 - field->id;
        colorField(field);
    }
}

void invertAt(int layer, int index)
{
    if(layer == 0)
    {
        invertField(layer, index);
        layer++;
        for(int i = 0; i < fieldSize ; i++)
        {
            invertField(layer, i);
        }
    }
    else if(layer == fieldSize + 1)
    {
        invertField(layer, index);
        layer--;
        for(int i = 0; i < fieldSize ; i++)
        {
            invertField(layer, i);
        }
    }
    else
    {
        invertField(layer, index);
        invertField(layer, (index + 1) % fieldSize);
        invertField(layer, (index - 1 + fieldSize) % fieldSize);
        invertField(layer + 1, index);
        invertField(layer - 1, index);
    }
}

void tick(int program)
{
    if(tickTime == -1)
    {
        tickTime = glfwGetTimerValue();
    }
    else
    {
        long time = glfwGetTimerValue();
        tickSum += time - tickTime;
        tickTime = time;
        
        tickCounter++;
    }
    
    vectorSetTo(&oldCamera, &camera);
    oldLengthAngle = lengthAngle;
    oldWidthAngle = widthAngle;
    
    float factor = 0.05f;
    if(keyIsDown(GLFW_KEY_A))
    {
        vectorAddMul(&camera, &left, factor);
    }
    if(keyIsDown(GLFW_KEY_D))
    {
        vectorAddMul(&camera, &right, factor);
    }
    if(keyIsDown(GLFW_KEY_W))
    {
        vectorAddMul(&camera, &front, factor);
    }
    if(keyIsDown(GLFW_KEY_S))
    {
        vectorAddMul(&camera, &back, factor);
    }
    if(keyIsDown(GLFW_KEY_SPACE))
    {
        vectorAddMul(&camera, &up, factor);
    }
    if(keyIsDown(GLFW_KEY_LEFT_SHIFT))
    {
        vectorAddMul(&camera, &down, factor);
    }
    
    if(mouseIsJustDown(GLFW_MOUSE_BUTTON_1) && selectedLayer != -1 && selectedIndex != -1)
    {
        invertAt(selectedLayer, selectedIndex);
        generateSphere();
        selectedLayer = -1;
        selectedIndex = -1;
    }
    
    widthAngle -= mouseY * 0.1f;
    lengthAngle -= mouseX * 0.1f;
    
    if(widthAngle >= 89.5)
    {
        widthAngle = 89.5f;
    }
    else if(widthAngle <= -89.5)
    {
        widthAngle = -89.5f;
    }
    
    mouseX = 0.0f;
    mouseY = 0.0f;
}

void renderTick(int program, float lag)
{
    if(renderTickTime == -1)
    {
        renderTickTime = glfwGetTimerValue();
    }
    else
    {
        long time = glfwGetTimerValue();
        renderTickSum += time - renderTickTime;
        renderTickTime = time;
        
        renderTickCounter++;
    }
    
    updateView(program, lag);
    
    glBindBuffer(GL_ARRAY_BUFFER, vbo);
    glBindVertexArray(vba);
    glDrawArrays(GL_TRIANGLES, 0, vertices);
}

void onWindowResize(int width, int height)
{
    updateProjection((float) width / height, getProgram());
}

void onMouseMove(float x, float y)
{
    mouseX += x;
    mouseY += y;
}

int readPositiveInt(int from, int to, char* message, int error)
{
    fputs(message, stdout);
    fflush(stdout);
    
    int size = 16;
    int index = 0;
    char* buffer = malloc(sizeof(char) * size);
    
    while(1)
    {
        int c = fgetc(stdin);
        if(c == EOF)
        {
            free(buffer);
            return error;
        }
        else if(c == '\n')
        {
            int number = 0;
            int i = 0;
            while(i < index)
            {
                int n = buffer[i] - '0';
                if(n < 0 || n > 9)
                {
                    break;
                }
                number = number * 10 + n;
                if(number > to)
                {
                    break;
                }
                i++;
            }
            
            if(i >= index && number >= from)
            {
                free(buffer);
                return number;
            }
            
            fputs(message, stdout);
            fflush(stdout);
            index = 0;
            continue;
        }
        
        if(index >= size)
        {
            size *= 2;
            buffer = realloc(buffer, sizeof(char) * size);
        }
        buffer[index] = c;
        index++;
    }
}

int main()
{   
    /*fieldSize = readPositiveInt(5, 20, "Select a game size from 5 to 20:\n", 0);
    if(fieldSize == 0)
    {
        printf("Cannot read from stdin\n");
        return EXIT_SUCCESS;
    }
    quality = readPositiveInt(1, 9, "Select a rendering quality from 1 to 9:\n", 0);
    if(quality == 0)
    {
        printf("Cannot read from stdin\n");
        return EXIT_SUCCESS;
    }*/
    fieldSize = 5;
    quality = 8;
    
    if(startGame("Test Game", init, tick, renderTick, onWindowResize, onMouseMove))
    {
        fprintf(stderr, "Exited with error\n");
        //return EXIT_FAILURE;
    }
    
    if(data != NULL)
    {
        free(data);
    }
    if(gameFields != NULL)
    {
        free(gameFields);
    }
    
    glDeleteBuffers(1, &vbo);
    glDeleteVertexArrays(1, &vba);
    
    printf("_______________TPS_______________\n");
    printf("%ld  %ld  %ld\n", tickCounter, tickSum, tickTime);
    printf("%lf\n", (double) tickSum / tickCounter);
    printf("%lf\n", 1000000000.0 * tickCounter / tickSum);
    printf("_______________FPS_______________\n");
    printf("%ld  %ld  %ld\n", renderTickCounter, renderTickSum, renderTickTime);
    printf("%lf\n", (double) renderTickSum / renderTickCounter);
    printf("%lf\n", 1000000000.0 * renderTickCounter / renderTickSum);
    return EXIT_SUCCESS;
}