#include "board.h"
#include <cstdlib>
#include <iostream>

Board::Board() :
    selection_index(0),
    on_selection(false)
{}

Board::~Board()
{
    for (Cell *cell : vec_field)
    {
        delete cell->sprite;
        delete cell;
    }
}

void Board::draw(sf::RenderWindow& window)
{
    for (const Cell *cell : vec_field)
        window.draw(*cell->sprite);

    window.draw(rect_selection);
}

bool Board::moveSelection(const DIRECTION &direction)
{
    if (!on_selection)
    {
        switch (direction) {
        case DIRECTION::UP:
            if (selection_index < cells_on_width) // if upper row
                return false;
            selection_index -= cells_on_width;
            setSelectionVertex(selection_index);
            break;

        case DIRECTION::DOWN:
            if (selection_index > (cells_on_width * (cells_on_height - 1))) // if bottom row
                return false;
            selection_index += cells_on_width;
            setSelectionVertex(selection_index);
            break;

        case DIRECTION::RIGHT:
            ++selection_index;
            if (selection_index == vec_field.size()) // if the last cell of right bottom corner
                selection_index = 0; // move to the first cell of upper left corner
            setSelectionVertex(selection_index);
            break;

        case DIRECTION::LEFT:
            if (selection_index == 0) // if the first cell of of upper left corner
                selection_index = vec_field.size() - 1; // move to the last cell of right bottom corner
            else
                --selection_index;
            setSelectionVertex(selection_index);
            break;

        default:
            return false;
            break;
        }

        return true;
    }

    switch (direction) {
    case DIRECTION::UP:
        if (selection_index < cells_on_width) // if upper row
            return false;
        swapCells(selection_index, selection_index - cells_on_width);
        selection_index -= cells_on_width;
        setSelectionVertex(selection_index);
        break;

    case DIRECTION::DOWN:
        if (selection_index > (cells_on_width * (cells_on_height - 1))) // if bottom row
            return false;
        swapCells(selection_index, selection_index + cells_on_width);
        selection_index += cells_on_width;
        setSelectionVertex(selection_index);
        break;

    case DIRECTION::RIGHT:
        if ((selection_index + 1) % cells_on_width == 0)
            return false;
        swapCells(selection_index, selection_index + 1);
        ++selection_index;
        setSelectionVertex(selection_index);
        break;

    case DIRECTION::LEFT:
        if (((selection_index % cells_on_width == 0) && (selection_index > cells_on_width)) || selection_index == 0)
            return false;
        swapCells(selection_index, selection_index - 1);
        --selection_index;
        setSelectionVertex(selection_index);
        break;

    default:
        return false;
        break;
    }

    on_selection = false;
    return true;
}

void Board::onSelectionMode()
{
    on_selection = !on_selection;
}

void Board::setSelectionVertex(Cells::size_type index)
{
    const auto& cell = vec_field[index];
    const auto& pos = cell->sprite->getPosition();
    const auto& x = pos.x;
    const auto& y = pos.y;
    const float length = static_cast<float>(Cell::side_length);

    rect_selection = sf::VertexArray(sf::LinesStrip, 5);
    rect_selection[0].position = pos;
    rect_selection[0].color  = sf::Color::Red;
    rect_selection[1].position = sf::Vector2f(x + length, y);
    rect_selection[1].color = sf::Color::Red;
    rect_selection[2].position = sf::Vector2f(x + length, y + length);
    rect_selection[2].color = sf::Color::Red;
    rect_selection[3].position = sf::Vector2f(x, y + length);
    rect_selection[3].color = sf::Color::Red;
    rect_selection[4].position = pos;
    rect_selection[4].color = sf::Color::Red;
}

void Board::swapCells(Cells::size_type curr_index, Cells::size_type swap_index)
{
    Cell *curr_cell = vec_field[curr_index];
    Cell *swap_cell = vec_field[swap_index];
    const sf::Vector2f temp_pos = curr_cell->sprite->getPosition();
    const Cells::size_type temp_cell_index = curr_cell->current_index;

    curr_cell->sprite->setPosition(swap_cell->sprite->getPosition());
    curr_cell->current_index = swap_cell->current_index;

    swap_cell->sprite->setPosition(temp_pos);
    swap_cell->current_index = temp_cell_index;

    Cell* temp = vec_field[curr_index];
    vec_field[curr_index] = vec_field[swap_index];
    vec_field[swap_index] = temp;
}

bool Board::isWinCondition() const
{
    return std::all_of(vec_field.begin(), vec_field.end(), [](const Cell *cell){ return cell->current_index == cell->inital_index; });
}

bool Board::init(const std::string& path, int splitting, const sf::RenderWindow &window)
{
    // PREPARING INITIAL BOARD STATE //

    if (!global_texture.loadFromFile(path) )
        return false;

    const int width  = global_texture.getSize().x;
    const int height = global_texture.getSize().y;

    Cell::side_length = (width < height) ? width / splitting : height / splitting;
    cells_on_height = height / Cell::side_length;
    cells_on_width  = width  / Cell::side_length;

    vec_field.reserve(cells_on_height * cells_on_width);

    /* Iterating board cells' screen positions.
     * The initial image after this would look exactly like the loaded picture, not shuffled yet. */
    Cells::size_type index = 0;
    for (int x = 0; x < height; x += Cell::side_length)
    {
        if ((height - x) >= Cell::side_length)
        {
            for (int y = 0; y < width; y += Cell::side_length)
            {
                if ((width - y) >= Cell::side_length)
                {
                    sf::Sprite* sp = new sf::Sprite(global_texture, sf::IntRect(y, x, Cell::side_length, Cell::side_length));
                    sp->setPosition(static_cast<float>(y), static_cast<float>(x));

                    vec_field.push_back(new Cell({index, index, sp}));
                    ++index;
                }
            }
        }
    }

    // SCALING //

    float scaling = 0.;
    if (width >= height && width > static_cast<int>(window.getSize().x))
        scaling = static_cast<float>(window.getSize().x) / static_cast<float>(width);
    if (height >= width && height > static_cast<int>(window.getSize().y))
        scaling = static_cast<float>(window.getSize().y) / static_cast<float>(height);

    if (scaling != 0.)
    {
        // Calculating new size of each tile
        int old_side_length = Cell::side_length;
        Cell::side_length = static_cast<int>(static_cast<float>(Cell::side_length) * scaling);
        int shift = Cell::side_length - old_side_length;
        float move_x, move_y;
        // Moving all scaled tiles up and left, to remove spacing
        for (Cells::size_type i = 0; i < vec_field.size(); ++i)
        {
            move_x = 0.f;
            move_y = 0.f;
            // The first column isn't allowed to move by x
            if (!(((i % cells_on_width == 0) && (i >= cells_on_width))))
                move_x = static_cast<float>(shift) * static_cast<float>((i < cells_on_width) ? i : i % cells_on_width);
            // The first row isn't allowed to move by y
            if (i >= cells_on_width)
                move_y = static_cast<float>(shift) * static_cast<float>(i / cells_on_width);

            vec_field[i]->sprite->scale(scaling, scaling);
            vec_field[i]->sprite->move(move_x, move_y);
        }

    }


    // SHUFFLING //

    srand(static_cast<unsigned int>(time(nullptr)));
    for (Cells::size_type curr_i = 0; curr_i < vec_field.size(); ++curr_i)
    {
        Cells::size_type swap_i;
        do
        {   // find two different tiles
           swap_i = rand() & (vec_field.size() - 1);
        } while (curr_i == swap_i);

        swapCells(curr_i, swap_i);
    }

    // Set initial position of cursor
    setSelectionVertex(selection_index);

    return true;
}

int Board::Cell::side_length = 0;