#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include "glad/glad.h"
#include <GLFW/glfw3.h>
#include "cglm/cglm.h"
#include "lib.h"
#include "stb_image.h"

#define PI 3.14159f

int SCREEN_WIDTH = 1024;
int SCREEN_HEIGHT = 768;

typedef struct State {
    float camX;
    float camY;
    float px;
    float py;
} State;

void framebuffer_size_callback(GLFWwindow* window, int width, int height) {
    (void)window;
    glViewport(0, 0, width, height);
    SCREEN_WIDTH = width;
    SCREEN_HEIGHT = height;
}

void processInput(GLFWwindow *window, State* state) {
    if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS) {
        glfwSetWindowShouldClose(window, true);
    }

    float amount = 1.0f;
    if (glfwGetKey(window, GLFW_KEY_UP) == GLFW_PRESS) {
        state->camY -= amount;
    }
    if (glfwGetKey(window, GLFW_KEY_DOWN) == GLFW_PRESS) {
        state->camY += amount;
    }
    if (glfwGetKey(window, GLFW_KEY_LEFT) == GLFW_PRESS) {
        state->camX -= amount;
    }
    if (glfwGetKey(window, GLFW_KEY_RIGHT) == GLFW_PRESS) {
        state->camX += amount;
    }
    amount = 1.1f;
    if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS) {
        state->py -= amount;
    }
    if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS) {
        state->py += amount;
    }
    if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS) {
        state->px -= amount;
    }
    if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS) {
        state->px += amount;
    }
}

int main(void) {
    glfwInit();

    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

    GLFWwindow* window =
        checkPtr(glfwCreateWindow(SCREEN_WIDTH, SCREEN_HEIGHT, "2D Engine", NULL, NULL),
                 "Error creating GLFW window");
    if (window == NULL) glfwTerminate();

    glfwMakeContextCurrent(window);

    checkCode(gladLoadGLLoader((GLADloadproc)glfwGetProcAddress), "Error initializing GLAD");

    glViewport(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT);

    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);

    unsigned int shaderProgram =
        compileShaderProgram("shaders/main.vert", "shaders/main.frag", NULL);

    glEnable(GL_FRAMEBUFFER_SRGB);
    glDisable(0x809D);
    glEnable(GL_BLEND);
    // CHECK: Do we need this?
    // glEnable(GL_DEPTH_TEST);
    // glDepthFunc(GL_GREATER);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

    float vertices[] = {
        // pos      // tex
        0.0f, 1.0f, 0.0f, 1.0f,
        1.0f, 0.0f, 1.0f, 0.0f,
        0.0f, 0.0f, 0.0f, 0.0f,

        0.0f, 1.0f, 0.0f, 1.0f,
        1.0f, 1.0f, 1.0f, 1.0f,
        1.0f, 0.0f, 1.0f, 0.0f
    };

    unsigned int VBO, VAO;
    glGenVertexArrays(1, &VAO);
    glGenBuffers(1, &VBO);

    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    glBindVertexArray(VAO);
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 4 * sizeof(float), (void*)0);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glBindVertexArray(0);

    mat4 camOrtho;
    glm_ortho(0.0f, SCREEN_WIDTH, SCREEN_HEIGHT, 0.0f, -1.0f, 1.0f, camOrtho);

    unsigned int textureID;
    int width, height, channels;
    char* data = (char*)stbi_load("assets/idle.png", &width, &height, &channels, 4);
    if (data == NULL) {
        fprintf(stderr, "Could not load texture");
        return -1;
    }

    glGenTextures(1, &textureID);
    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, textureID);
    // // set Texture wrap and filter modes
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_SRGB8_ALPHA8, width, height, 0,
                 GL_RGBA, GL_UNSIGNED_BYTE, data);

    stbi_image_free(data);
    // glBindTexture(GL_TEXTURE_2D, 0);

    // float deltaTime = 0.0f;
    // float lastFrame = 0.0f;
    State state = {0};
    int frameCount = 0;
    float elapsed = 0.0f;
    float lastFrame;
    while (!glfwWindowShouldClose(window)) {

        float currentFrame = glfwGetTime();
        float deltaTime = currentFrame - lastFrame;
        lastFrame = currentFrame;

        processInput(window, &state);

        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);


        glUseProgram(shaderProgram);

        // vec4 vec = {1.0f, 0.0f, 0.0f, 1.0f};
        mat4 model;
        mat4 projection;
        glm_mat4_identity(model);
        glm_mat4_identity(projection);
        float pivotx = 0.5f;
        float pivoty = 0.5f;
        glm_translate(model, (vec3){state.px, state.py, 0.0f});
        glm_translate(model, (vec3){0.f, 0.f, 0.0f});
        glm_translate(model, (vec3){pivotx, pivoty, 0.0f});
        // glm_rotate(model, currentFrame, (vec3){0.0f, 0.0f, 1.0f});
        glm_scale(model, (vec3){100.0f, 100.0f, 0.0f});
        glm_translate(model, (vec3){-pivotx, -pivoty, 0.0f});
        // printf("X:%f Y:%f Z:%f\n", projection[3][0], projection[3][1], projection[3][2]);

        float worldUnitSizeInPixels = 2; // Desired size of a 1x1 area on the screen
        float hw = (SCREEN_WIDTH / 2.f) / worldUnitSizeInPixels;
        float hh = (SCREEN_HEIGHT / 2.f) / worldUnitSizeInPixels;

        glm_ortho(-hw, hw, hh, -hh, -1.0f, 1.0f, projection);
        glm_translate(projection, (vec3){0.0f + state.camX, 0.0f + state.camY, 0.0f});

        GLint location = glGetUniformLocation(shaderProgram, "model");
        glUniformMatrix4fv(location, 1, GL_FALSE, model[0]);

        location = glGetUniformLocation(shaderProgram, "projection");
        glUniformMatrix4fv(location, 1, GL_FALSE, projection[0]);

        location = glGetUniformLocation(shaderProgram, "spriteColor");
        glUniform3f(location, 1.0f, 1.0f, 1.0f);

        elapsed += deltaTime;
        if (elapsed >  0.1f) {
            frameCount += 1;
            if (frameCount > 9) {
                frameCount = 0;
            }
            elapsed = 0.0f;
        }

        location = glGetUniformLocation(shaderProgram, "spriteX");
        float spriteX = (float)frameCount / 10;
        glUniform1f(location, spriteX);

        location = glGetUniformLocation(shaderProgram, "spriteY");
        glUniform1f(location, state.py);

        glUniform1i(glGetUniformLocation(shaderProgram, "image"), 0);

        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_2D, textureID);

        glBindVertexArray(VAO);
        glDrawArrays(GL_TRIANGLES, 0, 6);
        glBindVertexArray(0);

        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    glDeleteVertexArrays(1, &VAO);
    glDeleteBuffers(1, &VBO);
    glDeleteProgram(shaderProgram);
    glfwTerminate();
    return 0;
}