#include <GLFW/glfw3.h>
#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

const int scrW = 1280, scrH = 960;

//СНАЧАЛА y, ПОТОМ x
GLubyte vertexContainer[scrH][scrW][3] = {0};

// Y снизу вверх
// X слева направо

struct vertex {
    GLdouble x, y;
};

bool isPaintedOver(const GLubyte *mas) {
    return mas[0] || mas[1] || mas[2];
}

vector<vertex> mas;

int flag = 0;
int flagCanDraw = 1;
int someHappend = 0;

void drawPixel(int x, int y) {
    vertexContainer[y][x][0] = 0;
    vertexContainer[y][x][1] = 255;
    vertexContainer[y][x][2] = 255;
}

void drawline(int x1, int y1, int x2, int y2) {
    const int deltaX = abs(x2 - x1);
    const int deltaY = abs(y2 - y1);
    const int signX = x1 < x2 ? 1 : -1;
    const int signY = y1 < y2 ? 1 : -1;
    int error = deltaX - deltaY;
    drawPixel(x2, y2);
    while(x1 != x2 || y1 != y2) {
        drawPixel(x1, y1);
        const int error2 = error * 2;
        if (error2 > -deltaY) {
            error -= deltaY;
            x1 += signX;
        }
        if (error2 < deltaX) {
            error += deltaX;
            y1 += signY;
        }
    }

}


//void draw() {
//
//    for (int x = 0; x < scrW; x++) {
//        for (int y = 0; y < scrH; y++) {
//            vertexContainer[x][y][0] = 0;
//            vertexContainer[x][y][1] = 255;
//            vertexContainer[x][y][2] = 255;
//        }
//    }
//
//    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
//    glPixelStorei(GL_UNPACK_ROW_LENGTH, scrW); //длина строки
//    glPixelStorei(GL_UNPACK_SKIP_ROWS, 0); // сколько строк пропустить?
//    glPixelStorei(GL_UNPACK_SKIP_PIXELS, 0); // сколько пикселов пропустить в каждой строке?
//
//    glRasterPos2i(0, 0);
//    glDrawPixels(scrW, scrH, GL_RGB, GL_UNSIGNED_BYTE, vertexContainer);
//
//}

void fill() {
    for (int y = scrH - 1; y >= 0; y--) {
        int flagDraw = 0;

        int countConstDraw = 0;
        int countDraw = 0;
        int lastDraw = 0;

        for (int x = 0; x < scrW; x++) {
            if (isPaintedOver(vertexContainer[y][x])) {
                countConstDraw++;
            }
        }

        for (int x = 0; x < scrW; x++) {
            if (isPaintedOver(vertexContainer[y][x])) {
                if (flagDraw == 0) {
                    if (x > 0) {
                        if (lastDraw == x - 1) {
                            flagDraw = 0;
                        } else {
                            flagDraw = 1;
                        }
                    } else {
                        flagDraw = 1;
                    }
                    countDraw++;
                    lastDraw = x;
                } else if (flagDraw == 1) {
                    flagDraw = 1;
                    countDraw++;
                    lastDraw = x;
                } else if (flagDraw == 2) {
                    flagDraw = 0;
                    countDraw++;
                    lastDraw = x;
                }
            } else {
                if (flagDraw == 0) {
                    flagDraw = 0;
                } else if (flagDraw == 1) {
                    if (isPaintedOver(vertexContainer[y + 1][x])) {
                        flagDraw = 2;
                    } else {
                        flagDraw = 0;
                    }
                } else if (flagDraw == 2) {
                    flagDraw = 2;
                }
            }

            if (y < scrH - 1) {
                if (flagDraw == 2 && countConstDraw != countDraw) {
                    drawPixel(x, y);
                }
            }

        }
    }
    cout << "I fill" << endl;
    someHappend = 0;
}

void drawEdges() {

    if (mas.size() > 1) {
        for (int i = 0; i < mas.size() - 1; i++) {
            drawline(mas[i].x, mas[i].y, mas[i + 1].x, mas[i + 1].y);
        }

        if (flag == 1) {
            drawline(mas[mas.size() - 1].x, mas[mas.size() - 1].y, mas[0].x, mas[0].y);
        }

        glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
        glPixelStorei(GL_UNPACK_ROW_LENGTH, scrW);
        glPixelStorei(GL_UNPACK_SKIP_ROWS, 0);
        glPixelStorei(GL_UNPACK_SKIP_PIXELS, 0);

        glRasterPos2i(0, 0);
        glDrawPixels(scrW, scrH, GL_RGB, GL_UNSIGNED_BYTE, vertexContainer);

        if (flag == 2 && someHappend == 1) {
            fill();
        }
    }

}

void keyCallback(GLFWwindow *window, int key, int scancode, int action, int mods) {
    if (action == GLFW_PRESS) {
        switch (key) {
            case GLFW_KEY_1:
                flag = 1;
                flagCanDraw = 0;
                break;
            case GLFW_KEY_2:
                flag = 2;
                flagCanDraw = 0;
                someHappend = 1;
                break;
            case GLFW_KEY_C:
                mas.clear();
                for (int y = 0; y < scrH; y++) {
                    for (int x = 0; x < scrW; x++) {
                        vertexContainer[y][x][0] = 0;
                        vertexContainer[y][x][1] = 0;
                        vertexContainer[y][x][2] = 0;
                    }
                }
                flag = 0;
                flagCanDraw = 1;
                break;
            case GLFW_KEY_P:
                for (int y = scrH - 1; y >= 0; y--){
                    cout << "stroka y: " << y << endl;
                    for (int x = 0; x < scrW; x++) {
                        cout << int(isPaintedOver(vertexContainer[y][x])) << " ";
                    }
                    cout << endl;
                }
        }
    }
}

void mouseCallback(GLFWwindow *window, int button, int action, int mods) {
    if (flagCanDraw) {
        if (button == GLFW_MOUSE_BUTTON_LEFT && action == GLFW_PRESS) {
            GLdouble x, y;
            glfwGetCursorPos(window, &x, &y);
            vertex vertexLeftBut;
            vertexLeftBut.x = x;
            vertexLeftBut.y = scrH - y;
            mas.push_back(vertexLeftBut);
        }
    }

}


int main() {
    GLFWwindow *window;


    if (!glfwInit()) {
        return -1;
    }

    window = glfwCreateWindow(scrW, scrH, "Lab4", NULL, NULL);

    glfwSetKeyCallback(window, keyCallback);
    glfwSetMouseButtonCallback(window, mouseCallback);

    glfwSetInputMode(window, GLFW_STICKY_KEYS, 1);

    int screenW, screenH;
    glfwGetFramebufferSize(window, &screenW, &screenH);

    if (!window) {
        glfwTerminate();
        return -1;
    }

    glfwMakeContextCurrent(window);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();


    while (!glfwWindowShouldClose(window)) {

        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
        glPushMatrix();
        glOrtho(0.0, scrW, 0.0, scrH, -1.0, 1.0);
        glViewport(0, 0, screenW, screenH);

        drawEdges();

        glEnd();
        glPopMatrix();

        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    glfwTerminate();

    return 0;
}