#include "SynEngine.hpp"

enum PlayerSprite
{
    Empty,
    Point,
    Straight,
    Curved,
    Back,
    Head,
    PointGot,
    GameOver
};

struct SnakePart
{
    sf::Vector2i cellPosition;
    unsigned direction;
};

class Snake : public IBehaviour
{
    private:
        std::vector<SnakePart> snake;
        unsigned int lenght;
        SnakePart *head;
        Timer *timer;
        Grid *grid;
        float timeCountdown;
        float timeResetValue;
        unsigned TickPerSec;
        GameConfiguration *config;

        void Move();
        void Grow();
        unsigned GetDirection(sf::Vector2i, sf::Vector2i);
        unsigned GetBackDirection();
        sf::Vector2i GetDirectionVector(unsigned);
        PlayerSprite GetNewSprite(unsigned &);
    public:
        Snake();
        void Update();
        ~Snake();
};

Snake::Snake()
{
    TickPerSec = 4;
    timeResetValue = 1.0 / (float)TickPerSec;
    timeCountdown = timeResetValue;
    lenght = 2;
    snake.reserve(lenght);

    for (unsigned i = 0; i < lenght; i++)
        snake.push_back({ sf::Vector2i(1 - i, 0), 0});
    
    timer = &GameManager::timer;
    head = &snake[0];
    config = GameManager::GetConfig();
    grid = &GameManager::GetGrid();

    grid -> UpdateCell(snake[0].cellPosition.x, snake[0].cellPosition.y, PlayerSprite::Head, 0);
    grid -> UpdateCell(snake[1].cellPosition.x, snake[1].cellPosition.y, PlayerSprite::Straight, 0);
}

void Snake::Move()
{
    sf::Vector2i *backPosition   = &snake[lenght - 1].cellPosition;
    sf::Vector2i *secondPosition = &snake[1].cellPosition;
    sf::Vector2i headPosition = head -> cellPosition;
    unsigned direction;
    unsigned headDirection;
    PlayerSprite sprite;
    
    grid -> UpdateCell(backPosition -> x, -backPosition -> y, PlayerSprite::Empty);
    
    headDirection = head -> direction;
    snake.pop_back();
    
    // Check if the new direction is opposite to the head's direction
    if((GameManager::GetInputDirection() + 2) % 4 == headDirection)
        headPosition += GetDirectionVector(headDirection);
    else
    {
        headPosition += GameManager::GetInputVector();
        headDirection = GameManager::GetInputDirection();
    }
    snake.insert(snake.begin(), { headPosition, headDirection });

    direction = snake[1].direction;
    sprite = GetNewSprite(direction);

    grid -> UpdateCell(headPosition.x, -headPosition.y, PlayerSprite::Head, headDirection);
    grid -> UpdateCell(secondPosition -> x, -secondPosition -> y, sprite, (int)direction); 
    grid -> UpdateCell(backPosition -> x, -backPosition -> y, PlayerSprite::Back, GetBackDirection()); 
}

void Snake::Update()
{
    if(timeCountdown > 0.0)
    {
        timeCountdown -= timer -> GetDeltaTime();
        return;
    }
    
    Move();
    timeCountdown = timeResetValue;
}

sf::Vector2i Snake::GetDirectionVector(unsigned direction)
{
    switch (direction)
    {
    case 0: return sf::Vector2i(1, 0);
    case 1: return sf::Vector2i(0, -1);
    case 2: return sf::Vector2i(-1, 0);
    case 3: return sf::Vector2i(0, 1);
    default: return sf::Vector2i(1, 0);
    }
}

PlayerSprite Snake::GetNewSprite(unsigned &direction)
{
    SnakePart *third = &snake[2];
    SnakePart *second = &snake[1];
    sf::Vector2i vector = third -> cellPosition - head -> cellPosition;
    unsigned newDirection = GameManager::GetInputDirection();


    // I need to update this. It look so bad
    if(vector.x != 0 && vector.y != 0)
    {
        direction += 2;
        direction %= 4;
        if(direction > newDirection)
        {
            unsigned temp;
            temp = direction;
            direction = newDirection;
            newDirection = temp;
        }
        
        // 0 - 1 -> 0
        // 1 - 2 -> 1
        // 2 - 3 -> 2
        // 0 - 3 -> 3
        if(direction == 0 && newDirection == 3)
            direction = 3;

        return PlayerSprite::Curved;
    }
    
    direction = GetDirection(head -> cellPosition, second -> cellPosition);
    return PlayerSprite::Straight;
}

unsigned Snake::GetDirection(sf::Vector2i first, sf::Vector2i second)
{
    first -= second;

    if(first.x > 0) return 0;
    if(first.y < 0) return 1;
    if(first.x < 0) return 2;
    if(first.y > 0) return 3;
    return 0;
}

unsigned Snake::GetBackDirection()
{
    return GetDirection(snake[lenght - 2].cellPosition, snake[lenght - 1].cellPosition);
}

Snake::~Snake()
{
}