/*******************************************************************
** This code is part of Breakout.
**
** Breakout is free software: you can redistribute it and/or modify
** it under the terms of the CC BY 4.0 license as published by
** Creative Commons, either version 4 of the License, or (at your
** option) any later version.
******************************************************************/
#include <algorithm>

#include "game.h"
#include "resource_manager.h"
#include "sprite_renderer.h"
#include "game_object.h"
#include "ball_object.h"
#include "particle_generator.h"
#include "post_processor.h"


// Game-related State data
SpriteRenderer    *Renderer;
GameObject        *Player;
BallObject        *Ball;
ParticleGenerator *Particles;
PostProcessor     *Effects;
GLfloat            ShakeTime = 0.0f;

Game::Game(GLuint width, GLuint height) 
	: State(GAME_ACTIVE), Keys(), Width(width), Height(height) 
{ 

}

Game::~Game()
{
    delete Renderer;
    delete Player;
    delete Ball;
    delete Particles;
    delete Effects;
}

void Game::Init()
{
    // Load shaders
    ResourceManager::LoadShader("shaders/sprite.vs", "shaders/sprite.frag", nullptr, "sprite");
    ResourceManager::LoadShader("shaders/particle.vs", "shaders/particle.frag", nullptr, "particle");
    ResourceManager::LoadShader("shaders/post_processing.vs", "shaders/post_processing.frag", nullptr, "postprocessing");
    // Configure shaders
    glm::mat4 projection = glm::ortho(0.0f, static_cast<GLfloat>(this->Width), static_cast<GLfloat>(this->Height), 0.0f, -1.0f, 1.0f);
    ResourceManager::GetShader("sprite").Use().SetInteger("sprite", 0);
    ResourceManager::GetShader("sprite").SetMatrix4("projection", projection);
    ResourceManager::GetShader("particle").Use().SetInteger("sprite", 0);
    ResourceManager::GetShader("particle").SetMatrix4("projection", projection);
    // Load textures
    ResourceManager::LoadTexture("textures/background.jpg", GL_FALSE, "background");
    ResourceManager::LoadTexture("textures/awesomeface.png", GL_TRUE, "face");
    ResourceManager::LoadTexture("textures/block.png", GL_FALSE, "block");
    ResourceManager::LoadTexture("textures/block_solid.png", GL_FALSE, "block_solid");
    ResourceManager::LoadTexture("textures/paddle.png", GL_TRUE, "paddle");
    ResourceManager::LoadTexture("textures/particle.png", GL_TRUE, "particle");
    ResourceManager::LoadTexture("textures/powerup_speed.png", GL_TRUE, "powerup_speed");
    ResourceManager::LoadTexture("textures/powerup_sticky.png", GL_TRUE, "powerup_sticky");
    ResourceManager::LoadTexture("textures/powerup_increase.png", GL_TRUE, "powerup_increase");
    ResourceManager::LoadTexture("textures/powerup_confuse.png", GL_TRUE, "powerup_confuse");
    ResourceManager::LoadTexture("textures/powerup_chaos.png", GL_TRUE, "powerup_chaos");
    ResourceManager::LoadTexture("textures/powerup_passthrough.png", GL_TRUE, "powerup_passthrough");
    // Set render-specific controls
    Renderer = new SpriteRenderer(ResourceManager::GetShader("sprite"));
    Particles = new ParticleGenerator(ResourceManager::GetShader("particle"), ResourceManager::GetTexture("particle"), 500);
    Effects = new PostProcessor(ResourceManager::GetShader("postprocessing"), this->Width, this->Height);
    // Load levels
    GameLevel one; one.Load("levels/one.lvl", this->Width, this->Height * 0.5);
    GameLevel two; two.Load("levels/two.lvl", this->Width, this->Height * 0.5);
    GameLevel three; three.Load("levels/three.lvl", this->Width, this->Height * 0.5);
    GameLevel four; four.Load("levels/four.lvl", this->Width, this->Height * 0.5);
    this->Levels.push_back(one);
    this->Levels.push_back(two);
    this->Levels.push_back(three);
    this->Levels.push_back(four);
    this->Level = 0;
    // Configure game objects
    glm::vec2 playerPos = glm::vec2(this->Width / 2 - PLAYER_SIZE.x / 2, this->Height - PLAYER_SIZE.y);
    Player = new GameObject(playerPos, PLAYER_SIZE, ResourceManager::GetTexture("paddle"));
    glm::vec2 ballPos = playerPos + glm::vec2(PLAYER_SIZE.x / 2 - BALL_RADIUS, -BALL_RADIUS * 2);
    Ball = new BallObject(ballPos, BALL_RADIUS, INITIAL_BALL_VELOCITY, ResourceManager::GetTexture("face"));
}

void Game::Update(GLfloat dt)
{
    // Update objects
    Ball->Move(dt, this->Width);
    // Check for collisions
    this->DoCollisions();
    // Update particles
    Particles->Update(dt, *Ball, 2, glm::vec2(Ball->Radius / 2));
    // Update PowerUps
    this->UpdatePowerUps(dt);
    // Reduce shake time
    if (ShakeTime > 0.0f)
    {
        ShakeTime -= dt;
        if (ShakeTime <= 0.0f)
            Effects->Shake = GL_FALSE;
    }
    // Check loss condition
    if (Ball->Position.y >= this->Height) // Did ball reach bottom edge?
    {
        this->ResetLevel();
        this->ResetPlayer();
    }
}


void Game::ProcessInput(GLfloat dt)
{
    if (this->State == GAME_ACTIVE)
    {
        GLfloat velocity = PLAYER_VELOCITY * dt;
        // Move playerboard
        if (this->Keys[GLFW_KEY_A])
        {
            if (Player->Position.x >= 0)
            {
                Player->Position.x -= velocity;
                if (Ball->Stuck)
                    Ball->Position.x -= velocity;
            }
        }
        if (this->Keys[GLFW_KEY_D])
        {
            if (Player->Position.x <= this->Width - Player->Size.x)
            {
                Player->Position.x += velocity;
                if (Ball->Stuck)
                    Ball->Position.x += velocity;
            }
        }
        if (this->Keys[GLFW_KEY_SPACE])
            Ball->Stuck = GL_FALSE;
    }
}

void Game::Render()
{
    if (this->State == GAME_ACTIVE)
    {
        // Begin rendering to postprocessing quad
        Effects->BeginRender();
            // Draw background
            Renderer->DrawSprite(ResourceManager::GetTexture("background"), glm::vec2(0, 0), glm::vec2(this->Width, this->Height), 0.0f);
            // Draw level
            this->Levels[this->Level].Draw(*Renderer);
            // Draw player
            Player->Draw(*Renderer);
            // Draw PowerUps
            for (PowerUp &powerUp : this->PowerUps)
                if (!powerUp.Destroyed)
                    powerUp.Draw(*Renderer);
            // Draw particles	
            Particles->Draw();
            // Draw ball
            Ball->Draw(*Renderer);
            // End rendering to postprocessing quad
        Effects->EndRender();
        // Render postprocessing quad
        Effects->Render(glfwGetTime());
    }
}


void Game::ResetLevel()
{
    if (this->Level == 0)this->Levels[0].Load("levels/one.lvl", this->Width, this->Height * 0.5f);
    else if (this->Level == 1)
        this->Levels[1].Load("levels/two.lvl", this->Width, this->Height * 0.5f);
    else if (this->Level == 2)
        this->Levels[2].Load("levels/three.lvl", this->Width, this->Height * 0.5f);
    else if (this->Level == 3)
        this->Levels[3].Load("levels/four.lvl", this->Width, this->Height * 0.5f);
}

void Game::ResetPlayer()
{
    // Reset player/ball stats
    Player->Size = PLAYER_SIZE;
    Player->Position = glm::vec2(this->Width / 2 - PLAYER_SIZE.x / 2, this->Height - PLAYER_SIZE.y);
    Ball->Reset(Player->Position + glm::vec2(PLAYER_SIZE.x / 2 - BALL_RADIUS, -(BALL_RADIUS * 2)), INITIAL_BALL_VELOCITY);
    // Also disable all active powerups
    Effects->Chaos = Effects->Confuse = GL_FALSE;
    Ball->PassThrough = Ball->Sticky = GL_FALSE;
    Player->Color = glm::vec3(1.0f);
    Ball->Color = glm::vec3(1.0f);
}


// PowerUps
GLboolean IsOtherPowerUpActive(std::vector<PowerUp> &powerUps, std::string type);

void Game::UpdatePowerUps(GLfloat dt)
{
    for (PowerUp &powerUp : this->PowerUps)
    {
        powerUp.Position += powerUp.Velocity * dt;
        if (powerUp.Activated)
        {
            powerUp.Duration -= dt;

            if (powerUp.Duration <= 0.0f)
            {
                // Remove powerup from list (will later be removed)
                powerUp.Activated = GL_FALSE;
                // Deactivate effects
                if (powerUp.Type == "sticky")
                {
                    if (!IsOtherPowerUpActive(this->PowerUps, "sticky"))
                    {	// Only reset if no other PowerUp of type sticky is active
                        Ball->Sticky = GL_FALSE;
                        Player->Color = glm::vec3(1.0f);
                    }
                }
                else if (powerUp.Type == "pass-through")
                {
                    if (!IsOtherPowerUpActive(this->PowerUps, "pass-through"))
                    {	// Only reset if no other PowerUp of type pass-through is active
                        Ball->PassThrough = GL_FALSE;
                        Ball->Color = glm::vec3(1.0f);
                    }
                }
                else if (powerUp.Type == "confuse")
                {
                    if (!IsOtherPowerUpActive(this->PowerUps, "confuse"))
                    {	// Only reset if no other PowerUp of type confuse is active
                        Effects->Confuse = GL_FALSE;
                    }
                }
                else if (powerUp.Type == "chaos")
                {
                    if (!IsOtherPowerUpActive(this->PowerUps, "chaos"))
                    {	// Only reset if no other PowerUp of type chaos is active
                        Effects->Chaos = GL_FALSE;
                    }
                }
            }
        }
    }
    // Remove all PowerUps from vector that are destroyed AND !activated (thus either off the map or finished)
    // Note we use a lambda expression to remove each PowerUp which is destroyed and not activated
    this->PowerUps.erase(std::remove_if(this->PowerUps.begin(), this->PowerUps.end(),
        [](const PowerUp &powerUp) { return powerUp.Destroyed && !powerUp.Activated; }
    ), this->PowerUps.end());
}

GLboolean ShouldSpawn(GLuint chance)
{
    GLuint random = rand() % chance;
    return random == 0;
}
void Game::SpawnPowerUps(GameObject &block)
{
    if (ShouldSpawn(75)) // 1 in 75 chance
        this->PowerUps.push_back(PowerUp("speed", glm::vec3(0.5f, 0.5f, 1.0f), 0.0f, block.Position, ResourceManager::GetTexture("powerup_speed")));
    if (ShouldSpawn(75))
        this->PowerUps.push_back(PowerUp("sticky", glm::vec3(1.0f, 0.5f, 1.0f), 20.0f, block.Position, ResourceManager::GetTexture("powerup_sticky")));
    if (ShouldSpawn(75))
        this->PowerUps.push_back(PowerUp("pass-through", glm::vec3(0.5f, 1.0f, 0.5f), 10.0f, block.Position, ResourceManager::GetTexture("powerup_passthrough")));
    if (ShouldSpawn(75))
        this->PowerUps.push_back(PowerUp("pad-size-increase", glm::vec3(1.0f, 0.6f, 0.4), 0.0f, block.Position, ResourceManager::GetTexture("powerup_increase")));
    if (ShouldSpawn(15)) // Negative powerups should spawn more often
        this->PowerUps.push_back(PowerUp("confuse", glm::vec3(1.0f, 0.3f, 0.3f), 15.0f, block.Position, ResourceManager::GetTexture("powerup_confuse")));
    if (ShouldSpawn(15))
        this->PowerUps.push_back(PowerUp("chaos", glm::vec3(0.9f, 0.25f, 0.25f), 15.0f, block.Position, ResourceManager::GetTexture("powerup_chaos")));
}

void ActivatePowerUp(PowerUp &powerUp)
{
    // Initiate a powerup based type of powerup
    if (powerUp.Type == "speed")
    {
        Ball->Velocity *= 1.2;
    }
    else if (powerUp.Type == "sticky")
    {
        Ball->Sticky = GL_TRUE;
        Player->Color = glm::vec3(1.0f, 0.5f, 1.0f);
    }
    else if (powerUp.Type == "pass-through")
    {
        Ball->PassThrough = GL_TRUE;
        Ball->Color = glm::vec3(1.0f, 0.5f, 0.5f);
    }
    else if (powerUp.Type == "pad-size-increase")
    {
        Player->Size.x += 50;
    }
    else if (powerUp.Type == "confuse")
    {
        if (!Effects->Chaos)
            Effects->Confuse = GL_TRUE; // Only activate if chaos wasn't already active
    }
    else if (powerUp.Type == "chaos")
    {
        if (!Effects->Confuse)
            Effects->Chaos = GL_TRUE;
    }
}

GLboolean IsOtherPowerUpActive(std::vector<PowerUp> &powerUps, std::string type)
{
    // Check if another PowerUp of the same type is still active
    // in which case we don't disable its effect (yet)
    for (const PowerUp &powerUp : powerUps)
    {
        if (powerUp.Activated)
            if (powerUp.Type == type)
                return GL_TRUE;
    }
    return GL_FALSE;
}


// Collision detection
GLboolean CheckCollision(GameObject &one, GameObject &two);
Collision CheckCollision(BallObject &one, GameObject &two);
Direction VectorDirection(glm::vec2 closest);

void Game::DoCollisions()
{
    for (GameObject &box : this->Levels[this->Level].Bricks)
    {
        if (!box.Destroyed)
        {
            Collision collision = CheckCollision(*Ball, box);
            if (std::get<0>(collision)) // If collision is true
            {
                // Destroy block if not solid
                if (!box.IsSolid)
                {
                    box.Destroyed = GL_TRUE;
                    this->SpawnPowerUps(box);
                }
                else
                {   // if block is solid, enable shake effect
                    ShakeTime = 0.05f;
                    Effects->Shake = GL_TRUE;
                }
                // Collision resolution
                Direction dir = std::get<1>(collision);
                glm::vec2 diff_vector = std::get<2>(collision);
                if (!(Ball->PassThrough && !box.IsSolid)) // don't do collision resolution on non-solid bricks if pass-through activated
                {
                    if (dir == LEFT || dir == RIGHT) // Horizontal collision
                    {
                        Ball->Velocity.x = -Ball->Velocity.x; // Reverse horizontal velocity
                        // Relocate
                        GLfloat penetration = Ball->Radius - std::abs(diff_vector.x);
                        if (dir == LEFT)
                            Ball->Position.x += penetration; // Move ball to right
                        else
                            Ball->Position.x -= penetration; // Move ball to left;
                    }
                    else // Vertical collision
                    {
                        Ball->Velocity.y = -Ball->Velocity.y; // Reverse vertical velocity
                        // Relocate
                        GLfloat penetration = Ball->Radius - std::abs(diff_vector.y);
                        if (dir == UP)
                            Ball->Position.y -= penetration; // Move ball bback up
                        else
                            Ball->Position.y += penetration; // Move ball back down
                    }
                }
            }
        }    
    }

    // Also check collisions on PowerUps and if so, activate them
    for (PowerUp &powerUp : this->PowerUps)
    {
        if (!powerUp.Destroyed)
        {
            // First check if powerup passed bottom edge, if so: keep as inactive and destroy
            if (powerUp.Position.y >= this->Height)
                powerUp.Destroyed = GL_TRUE;

            if (CheckCollision(*Player, powerUp))
            {	// Collided with player, now activate powerup
                ActivatePowerUp(powerUp);
                powerUp.Destroyed = GL_TRUE;
                powerUp.Activated = GL_TRUE;
            }
        }
    }

    // And finally check collisions for player pad (unless stuck)
    Collision result = CheckCollision(*Ball, *Player);
    if (!Ball->Stuck && std::get<0>(result))
    {
        // Check where it hit the board, and change velocity based on where it hit the board
        GLfloat centerBoard = Player->Position.x + Player->Size.x / 2;
        GLfloat distance = (Ball->Position.x + Ball->Radius) - centerBoard;
        GLfloat percentage = distance / (Player->Size.x / 2);
        // Then move accordingly
        GLfloat strength = 2.0f;
        glm::vec2 oldVelocity = Ball->Velocity;
        Ball->Velocity.x = INITIAL_BALL_VELOCITY.x * percentage * strength; 
        //Ball->Velocity.y = -Ball->Velocity.y;
        Ball->Velocity = glm::normalize(Ball->Velocity) * glm::length(oldVelocity); // Keep speed consistent over both axes (multiply by length of old velocity, so total strength is not changed)
        // Fix sticky paddle
        Ball->Velocity.y = -1 * abs(Ball->Velocity.y);

        // If Sticky powerup is activated, also stick ball to paddle once new velocity vectors were calculated
        Ball->Stuck = Ball->Sticky;
    }
}

GLboolean CheckCollision(GameObject &one, GameObject &two) // AABB - AABB collision
{
    // Collision x-axis?
    GLboolean collisionX = one.Position.x + one.Size.x >= two.Position.x &&
        two.Position.x + two.Size.x >= one.Position.x;
    // Collision y-axis?
    GLboolean collisionY = one.Position.y + one.Size.y >= two.Position.y &&
        two.Position.y + two.Size.y >= one.Position.y;
    // Collision only if on both axes
    return collisionX && collisionY;
}

Collision CheckCollision(BallObject &one, GameObject &two) // AABB - Circle collision
{
    // Get center point circle first 
    glm::vec2 center(one.Position + one.Radius);
    // Calculate AABB info (center, half-extents)
    glm::vec2 aabb_half_extents(two.Size.x / 2, two.Size.y / 2);
    glm::vec2 aabb_center(two.Position.x + aabb_half_extents.x, two.Position.y + aabb_half_extents.y);
    // Get difference vector between both centers
    glm::vec2 difference = center - aabb_center;
    glm::vec2 clamped = glm::clamp(difference, -aabb_half_extents, aabb_half_extents);
    // Now that we know the the clamped values, add this to AABB_center and we get the value of box closest to circle
    glm::vec2 closest = aabb_center + clamped;
    // Now retrieve vector between center circle and closest point AABB and check if length < radius
    difference = closest - center;
    
    if (glm::length(difference) < one.Radius) // not <= since in that case a collision also occurs when object one exactly touches object two, which they are at the end of each collision resolution stage.
        return std::make_tuple(GL_TRUE, VectorDirection(difference), difference);
    else
        return std::make_tuple(GL_FALSE, UP, glm::vec2(0, 0));
}

// Calculates which direction a vector is facing (N,E,S or W)
Direction VectorDirection(glm::vec2 target)
{
    glm::vec2 compass[] = {
        glm::vec2(0.0f, 1.0f),	// up
        glm::vec2(1.0f, 0.0f),	// right
        glm::vec2(0.0f, -1.0f),	// down
        glm::vec2(-1.0f, 0.0f)	// left
    };
    GLfloat max = 0.0f;
    GLuint best_match = -1;
    for (GLuint i = 0; i < 4; i++)
    {
        GLfloat dot_product = glm::dot(glm::normalize(target), compass[i]);
        if (dot_product > max)
        {
            max = dot_product;
            best_match = i;
        }
    }
    return (Direction)best_match;
}