#include <algorithm>
#include <stdlib.h>
#include <stdio.h>
#include "glad/glad.h"
#include <GLFW/glfw3.h>

#include "stb_image.h"

#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>

#include <iostream>
#include <filesystem>
#include <vector>
#include <math.h>

#include "collisions.h"
#include "player.h"
#include "shader.h"
#include "ghost.h"
#include "text.h"
#include "config.h"

void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void mouse_callback(GLFWwindow* window, double xpos, double ypos);
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset);
void set_light_front(int xoffset, int yoffset);

// player
Player *player;

// settings
unsigned int WINDOWWIDTH = 1600;
unsigned int WINDOWHEIGHT = 900;

// camera
bool first_frame = false;
float timed = 0.0f;
float last_frame = 0.0f;

float camera_speed = 20.0f;

const char *projectionC = "projection";
const char *viewC = "view";
const char *modelC = "model";

const char *objectcolorC = "objectcolor";
const char *viewposC = "viewPos";
const char *shininessC = "material.shininess";
const char *colorC = "material.color";
const char *lightposC = "light.position";
const char *directionC = "light.direction";
const char *largecutoffC = "light.largecutoff";
const char *smallcutoffC = "light.smallcutoff";
const char *ambientC = "light.ambient";
const char *diffuseC = "light.diffuse";
const char *specularC = "light.specular";

int num_walls;
float *wall_vertices;

int trailmax = 500;

int main(int argc, char *argv[]) {

    int success;
    glm::vec3 position;
    glm::vec3 start_position;
    float start_yaw;

    // Load configuration
    Config::loadFromFile("ghostland.json");
    camera_speed = Config::getFloat("camera_speed", camera_speed);

    FILE *fp = fopen("maze.txt", "r");
    float yaw;
    if (fscanf(fp, "%f %f %f %f\n", &position.x, &position.y, &position.z, &yaw) == EOF) {
        printf("1st fscanf failed.\n");
        return -1;
    }
    start_position = position;
    start_yaw = yaw;
    player = new Player(position, yaw);
    if (fscanf(fp, "%d\n", &num_walls) == EOF) {
        printf("2nd fscanf failed.\n");
        return -1;
    }
    player->num_walls = num_walls;
    // num surfaces * 6 (vertices per point) * 6 (floats per point)
    int num_wall_vertices = num_walls * 6 * 6;
    wall_vertices = (float *)calloc(sizeof(float), num_wall_vertices);
    float xmin_wall, xmax_wall, zmin_wall, zmax_wall;
    xmin_wall = 9999.9;
    xmax_wall = -9999.9;
    zmin_wall = 9999.9;
    zmax_wall = -9999.9;
    // read walls
    for (int i = 0; i < num_walls; i++) {
        for (int j = 0; j < 6; j++) {
            int vix = i*6*6 + j*6;
            if (fscanf(
                fp,
                "%f %f %f %f %f %f\n",
                &wall_vertices[vix],
                &wall_vertices[vix+1],
                &wall_vertices[vix+2],
                &wall_vertices[vix+3],
                &wall_vertices[vix+4],
                &wall_vertices[vix+5]
            ) == EOF) {
                printf("3rd fscanf failed.\n");
                return -1;
            }
            if (wall_vertices[vix] < xmin_wall) {
                xmin_wall = wall_vertices[vix];
            } else if (wall_vertices[vix] > xmax_wall) {
                xmax_wall = wall_vertices[vix];
            }
            if (wall_vertices[vix + 2] < zmin_wall) {
                zmin_wall = wall_vertices[vix + 2];
            } else if (wall_vertices[vix + 2] > zmax_wall) {
                zmax_wall = wall_vertices[vix + 2];
            }
        }
        if (fscanf(fp, "\n") == EOF) {
            printf("4th fscanf failed.\n");
            return -1;
        }
    }
    player->wall_vertices = wall_vertices;

    // read floor
    float *floor_vertices = (float *)calloc(sizeof(float), 6*6);
    for (int j = 0; j < 6; j++) {
        int vix = j*6;
        if (fscanf(
            fp,
            "%f %f %f %f %f %f\n",
            &floor_vertices[vix],
            &floor_vertices[vix+1],
            &floor_vertices[vix+2],
            &floor_vertices[vix+3],
            &floor_vertices[vix+4],
            &floor_vertices[vix+5]
        ) == EOF) {
            printf("floor fscanf failed.\n");
            return -1;
        }
    }
    fclose(fp);

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

    GLFWmonitor *monitor = glfwGetPrimaryMonitor();
    const GLFWvidmode *monitor_mode = glfwGetVideoMode(monitor);

    WINDOWWIDTH = monitor_mode->width;
    WINDOWHEIGHT = monitor_mode->height;
    //WINDOWWIDTH = 1280;
    //WINDOWHEIGHT = 960;

    GLFWwindow* window = glfwCreateWindow(WINDOWWIDTH, WINDOWHEIGHT, "Ghostland!", monitor, NULL);
    //GLFWwindow* window = glfwCreateWindow(WINDOWWIDTH, WINDOWHEIGHT, "Ghostland!", NULL, NULL);
    if (window == NULL)
    {
        printf("Failed to create GLFW window.\n");
        glfwTerminate();
        return -1;
    }
    glfwMakeContextCurrent(window);
    //glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
    glfwSetCursorPosCallback(window, mouse_callback);
    glfwSetScrollCallback(window, scroll_callback);

    glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);

    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
    {
        printf("Failed to initialize GLAD.\n");
        glfwTerminate();
        return -1;
    }

    glEnable(GL_DEPTH_TEST);
    //glEnable(GL_CULL_FACE);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

    int wall_program = create_shader_program("vertexshader.glsl", "fragmentshader.glsl");
    if (wall_program < 0) {
        glfwTerminate();
        return -1;
    }

    // Perhaps there's a better way of doing this, rather than re-compiling the same files?
    int floor_program = create_shader_program("vertexshader.glsl", "fragmentshader.glsl");
    if (wall_program < 0) {
        glfwTerminate();
        return -1;
    }

    // do stuff for walls
    unsigned int wallsVBO, wallsVAO;
    glGenVertexArrays(1, &wallsVAO);
    glGenBuffers(1, &wallsVBO);

    glBindVertexArray(wallsVAO);

    glBindBuffer(GL_ARRAY_BUFFER, wallsVBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(float) * num_wall_vertices, wall_vertices, GL_STATIC_DRAW);

    // position attribute
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
    glEnableVertexAttribArray(0);

    // normal attribute
    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)(3 * sizeof(float)));
    glEnableVertexAttribArray(1);

    // do stuff for floor
    unsigned int floorVBO, floorVAO;
    glGenVertexArrays(1, &floorVAO);
    glGenBuffers(1, &floorVBO);

    glBindVertexArray(floorVAO);

    glBindBuffer(GL_ARRAY_BUFFER, floorVBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(float) * 6 * 6 * 1, floor_vertices, GL_STATIC_DRAW);

    // position attribute
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
    glEnableVertexAttribArray(0);

    // normal attribute
    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)(3 * sizeof(float)));
    glEnableVertexAttribArray(1);

    // do stuff for trail
    float trail_vertices[] = {
        0.25f, 0.0f, 0.0f,
        -0.25f, 0.0f, 0.5f,
        -0.25f, 0.0f, -0.5f,

        -0.25f, 0.0f, 0.1f,
        -0.25f, 0.0f, -0.1f,
        -0.75f, 0.0f, 0.1f,

        -0.75f, 0.0f, 0.1f,
        -0.75f, 0.0f, -0.1f,
        -0.25f, 0.0f, -0.1f,
    };

    unsigned int trailVBO, trailVAO;
    glGenVertexArrays(1, &trailVAO);
    glGenBuffers(1, &trailVBO);

    glBindVertexArray(trailVAO);

    glBindBuffer(GL_ARRAY_BUFFER, trailVBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(float) * 3 * 3 * 3, trail_vertices, GL_STATIC_DRAW);

    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void *)0);
    glEnableVertexAttribArray(0);

    int trail_program = create_shader_program("trailshader.glsl", "trailfragshader.glsl");
    if (trail_program < 0) {
        glfwTerminate();
        return -1;
    }

    glm::vec3 *trail_positions = (glm::vec3 *)calloc(sizeof(glm::vec3), trailmax);
    float *trail_angles = (float *)calloc(sizeof(float), trailmax);
    int trail_ix = 0;
    int trail_sz = 0;

    // do stuff for ghosts
    // create program
    int ghost_program = create_shader_program("ghostshader.glsl", "ghostfragshader.glsl");
    if (ghost_program < 0) {
        glfwTerminate();
        return -1;
    }
    // ghost vertices
    float ghost_vertices[] = {
        -0.5f, -0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f,
         0.5f, -0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f,
         0.5f,  0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f,
         0.5f,  0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f,
        -0.5f,  0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f,
        -0.5f, -0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f,
    };
    unsigned int ghostVBO, ghostVAO;
    glGenVertexArrays(1, &ghostVAO);
    glBindVertexArray(ghostVAO);
    glGenBuffers(1, &ghostVBO);
    glBindBuffer(GL_ARRAY_BUFFER, ghostVBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(ghost_vertices), ghost_vertices, GL_STATIC_DRAW);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void *)0);
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void *)(3 * sizeof(float)));
    glEnableVertexAttribArray(1);
    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void *)(6 * sizeof(float)));
    glEnableVertexAttribArray(2);
    // ghost texture
    unsigned int ghost_texture;
    glGenTextures(1, &ghost_texture);
    glBindTexture(GL_TEXTURE_2D, ghost_texture);
    // set the texture wrapping parameters
    //glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_);
    //glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    // set texture filtering parameters
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    int width, height, numberChannels;
    //stbi_set_flip_vertically_on_load(true);
    unsigned char *ghost_data = stbi_load("ghost_facing_right.png", &width, &height, &numberChannels, 0);
    printf("Num channels: %d\n", numberChannels);
    if (!ghost_data) {
        printf("Failed to load texture!\n");
        glfwTerminate();
        return -1;
    }
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, ghost_data);
    glGenerateMipmap(GL_TEXTURE_2D);
    stbi_image_free(ghost_data);

    // do stuff for text
    int text_program;
    if (init_text(&text_program) < 0) {
        printf("Failed to load text module!\n");
        glfwTerminate();
        return -1;
    }
 
    // TODO move these into config file??
    int time_secI = 0, num_frames = 1;
    float time_sec;
    glm::vec3 wall_color = glm::vec3(0.61f, 0.6f, 0.59f);
    float wall_shininess = 6.5;
    glm::vec3 floor_color = glm::vec3(0.11f, 0.1f, 0.09f);
    float floor_shininess = 3.25;
    glm::vec3 ambient = glm::vec3(0.007f, 0.006f, 0.005f);
    glm::vec3 diffuse = glm::vec3(0.61f, 0.60f, 0.59f);
    glm::vec3 specular = glm::vec3(0.11f, 0.10f, 0.09f);

    float largecutoff = glm::cos(glm::radians(30.0f));
    float smallcutoff = glm::cos(glm::radians(7.5f));

    std::vector<Ghost *> ghosts;
    for (int i = 0; i < 800; i++) {
        Ghost *ghost = new Ghost(xmin_wall, xmax_wall, zmin_wall, zmax_wall);
        
        // Ensure ghost is not within 30.0 units of start_position
        while (glm::length(ghost->get_pos() - start_position) <= 30.0f) {
            ghost->regenerate_position();
        }
        
        ghosts.push_back(ghost);
    }

    player->mouse_callback(window, WINDOWWIDTH/2, WINDOWHEIGHT);

    int FPS = -1;

    while (!glfwWindowShouldClose(window))
    {
        float current_frame = static_cast<float>(glfwGetTime());
        int current_frameI = (int)current_frame;
        if (current_frameI != time_secI) {  // show stats every second
            FPS = num_frames;
            glm::vec3 player_pos = player->get_pos();
            float yaw, pitch;
            yaw = player->get_yaw();
            pitch = player->get_pitch();
            printf("FPS: %d\n", num_frames);
            printf("Player is at: (%f, %f, %f) facing (%f, %f)\n", player_pos.x, player_pos.y, player_pos.z, yaw, pitch);
            time_sec = current_frame;
            time_secI = current_frameI;
            num_frames = 1;
            trail_positions[trail_ix].x = player_pos.x;
            trail_positions[trail_ix].y = 6.5;
            trail_positions[trail_ix].z = player_pos.z;
            trail_angles[trail_ix] = yaw;
            //printf("Recorded trail %d: (%f, %f, %f) %f\n", trail_ix, trail_positions[trail_ix].x, trail_positions[trail_ix].y, trail_positions[trail_ix].z, yaw);
            trail_ix = (trail_ix + 1) % trailmax;
            if (trail_sz < trailmax) {
                trail_sz++;
            }
        } else { // otherwise increase number of frames
            num_frames++;
        }
        timed = current_frame - last_frame;
        last_frame = current_frame;
        if (!first_frame) {
            first_frame = true;
            continue;
        }

        player->process_input(window);

        glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        glUseProgram(wall_program);

        float fov = player->get_fov();
        glm::mat4 projection = glm::perspective(glm::radians(fov), (float)WINDOWWIDTH / (float)WINDOWHEIGHT, 0.1f, 256.0f);
        set_uniform(wall_program, projectionC, projection);

        glm::vec3 camera_pos, camera_front, camera_up;
        camera_pos = player->get_camera_pos();
        camera_front = player->get_camera_front();
        camera_up = player->get_camera_up();

        glm::mat4 view = glm::lookAt(camera_pos, camera_pos + camera_front, camera_up);
        set_uniform(wall_program, viewC, view);

        glm::mat4 model = glm::mat4(1.0f);
        set_uniform(wall_program, modelC, model);

        // light position
        glm::vec3 light_pos = player->get_light_pos();
        //printf("light_pos: (%f, %f, %f)\n", light_pos.x, light_pos.y, light_pos.z);
        glm::vec3 light_front = player->get_light_front();
        //printf("light_pos: (%f, %f, %f)\n", light_front.x, light_front.y, light_front.z);

        // Sort ghosts by distance to player for optimization
        glm::vec3 player_pos = player->get_pos();
        struct {
            bool operator()(const Ghost *a, const Ghost *b) const {
                glm::vec3 a_diff, b_diff;
                a_diff = player->get_pos() - a->get_pos();
                b_diff = player->get_pos() - b->get_pos();
                float a_dist, b_dist;
                a_dist = glm::length(a_diff);
                b_dist = glm::length(b_diff);
                return a_dist < b_dist;
            }
        } ghost_compare;
        std::partial_sort(ghosts.begin(), ghosts.begin() + ghosts.size() / 5, ghosts.end(), ghost_compare);
        
        // Calculate nearest ghost distance (first ghost is now closest)
        float nearest_ghost_distance = glm::length(ghosts[0]->get_pos() - player_pos);
        
        // Interpolate flashlight color based on nearest ghost distance
        // At 30.0+ units: (0.61, 0.60, 0.59) - normal color
        // At 10.0 units: (0.99, 0.60, 0.59) - red shift
        float color_factor = 1.0f;
        if (nearest_ghost_distance < 30.0f) {
            color_factor = (nearest_ghost_distance - 10.0f) / (30.0f - 10.0f);
            color_factor = glm::clamp(color_factor, 0.0f, 1.0f);
        }
        
        glm::vec3 normal_color = glm::vec3(0.61f, 0.60f, 0.59f);
        glm::vec3 danger_color = glm::vec3(0.99f, 0.60f, 0.59f);
        diffuse = glm::mix(danger_color, normal_color, color_factor);

        // fragment requirements
        set_uniform(wall_program, viewposC, camera_pos);
        set_uniform(wall_program, shininessC, wall_shininess);
        set_uniform(wall_program, colorC, wall_color);
        set_uniform(wall_program, lightposC, light_pos);
        set_uniform(wall_program, directionC, light_front);
        set_uniform(wall_program, largecutoffC, largecutoff);
        set_uniform(wall_program, smallcutoffC, smallcutoff);
        set_uniform(wall_program, ambientC, ambient);
        set_uniform(wall_program, diffuseC, diffuse);
        set_uniform(wall_program, specularC, specular);

        glBindVertexArray(wallsVAO);
        glDrawArrays(GL_TRIANGLES, 0, num_wall_vertices);

        glUseProgram(floor_program);

        set_uniform(floor_program, projectionC, projection);
        set_uniform(floor_program, viewC, view);
        set_uniform(floor_program, modelC, model);
        set_uniform(floor_program, viewposC, camera_pos);

        // fragment requirements
        set_uniform(floor_program, shininessC, floor_shininess);
        set_uniform(floor_program, colorC, floor_color);
        set_uniform(floor_program, lightposC, light_pos);
        set_uniform(floor_program, directionC, light_front);
        set_uniform(floor_program, largecutoffC, largecutoff);
        set_uniform(floor_program, smallcutoffC, smallcutoff);
        set_uniform(floor_program, ambientC, ambient);
        set_uniform(floor_program, diffuseC, diffuse);
        set_uniform(floor_program, specularC, specular);

        glBindVertexArray(floorVAO);
        glDrawArrays(GL_TRIANGLES, 0, 6 * 6 * 1);

        glUseProgram(trail_program);

        set_uniform(trail_program, projectionC, projection);
        set_uniform(trail_program, viewC, view);
        glm::vec3 trail_color = glm::vec3(1.0f, 0.0f, 0.0f);
        set_uniform(trail_program, objectcolorC, trail_color);

        for (int i = 0; i < trail_sz; i++) {
            glm::mat4 model = glm::mat4(1.0f);
            model = glm::translate(model, trail_positions[i]);
            model = glm::rotate(model, glm::radians(trail_angles[i]), glm::vec3(0.0f, -1.0f, 0.0f));
            set_uniform(trail_program, modelC, model);
            glBindVertexArray(trailVAO);
            glDrawArrays(GL_TRIANGLES, 0, 3 * 3 * 3);
        }

        glUseProgram(ghost_program);
        
        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_2D, ghost_texture);

        set_uniform(ghost_program, projectionC, projection);
        set_uniform(ghost_program, viewC, view);
        for (int i = ghosts.size()/5; i >= 0; i--) {
            glm::mat4 ghost_model = ghosts[i]->get_model(camera_pos);
            ghosts[i]->apply_movement(current_frame, timed);
            
            // Check if ghost is within 10.0 units of player
            glm::vec3 ghost_pos = ghosts[i]->get_pos();
            glm::vec3 player_pos = player->get_pos();
            float distance = glm::length(ghost_pos - player_pos);
            if (distance <= 10.0f) {
                player->reset_position(start_position, start_yaw);
            }
            
            // Check if ghost is within 30.0 units of start_position
            float start_distance = glm::length(ghost_pos - start_position);
            if (start_distance <= 30.0f) {
                ghosts[i]->reverse_direction_from_position(start_position);
            }
            
            set_uniform(ghost_program, modelC, ghost_model);
            glBindVertexArray(ghostVAO);
            glDrawArrays(GL_TRIANGLES, 0, (3 + 3 + 2) * 6);
        }

        if (FPS != -1) {
            glUseProgram(text_program);
            projection = glm::ortho(0.0f, static_cast<float>(WINDOWWIDTH), 0.0f, static_cast<float>(WINDOWHEIGHT));
            set_uniform(text_program, projectionC, projection);
            char fps_buff[256];
            sprintf(fps_buff, "FPS: %d", FPS);
            render_text(text_program, std::string(fps_buff), 25.0F, WINDOWHEIGHT - 35.0f, 0.5f, glm::vec3(1.0f, 0.0f, 0.0f));
        }

        player->apply_movement(timed);

        glfwSwapBuffers(window);
        glfwPollEvents();

    }

    glDeleteVertexArrays(1, &wallsVAO);
    glDeleteBuffers(1, &wallsVBO);

    glDeleteVertexArrays(1, &floorVAO);
    glDeleteBuffers(1, &floorVBO);

    glfwTerminate();
    return 0;
}

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

void mouse_callback(GLFWwindow* window, double xpos, double ypos) {
    player->mouse_callback(window, xpos, ypos);
}

void scroll_callback(GLFWwindow* window, double xoffset, double yoffset) {
    player->scroll_callback(window, xoffset, yoffset);
}