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

const std::string picture_dest = "art.png";

Board::Board(int splitting) :
    selection_index(0),
    on_selection(false)
{
    // PREPARING INITIAL BOARD STATE //

    if (!global_texture.loadFromFile(picture_dest) )
        return;

    const float width  = global_texture.getSize().x;
    const float 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);
    vec_ref.reserve(vec_field.size());

    /* 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(y, x);

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

    // SHUFFLING //

    srand(static_cast<unsigned int>(time(nullptr)));
    for (Cells::iterator curr_it = vec_field.begin(); curr_it != vec_field.end(); ++curr_it)
    {
        bool success = false;
        while (!success)
        {
            Cells::iterator swap_it = cellByCurrentIndex(rand() & (vec_field.size() - 1));
            if (curr_it->current_index == swap_it->current_index)
                continue;

            swapCells(curr_it, swap_it);
            success = true;
        }
    }

    setSelectionVertex(selection_index);
}

Board::~Board()
{
    for (Cell& cell : vec_field)
        delete cell.sprite;
}

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(cellByCurrentIndex(selection_index), cellByCurrentIndex(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(cellByCurrentIndex(selection_index), cellByCurrentIndex(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(cellByCurrentIndex(selection_index), cellByCurrentIndex(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(cellByCurrentIndex(selection_index), cellByCurrentIndex(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 = cellByCurrentIndex(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_cell_ind, Cells::size_type swap_cell_ind)
{
    auto& curr_cell = vec_field[curr_cell_ind];
    auto& swap_cell = vec_field[swap_cell_ind];
    const sf::Vector2f temp_pos = curr_cell.sprite->getPosition();
    const Cells::size_type temp_cell_index = curr_cell.current_index;

    curr_cell.sprite->setPosition(vec_field[swap_cell_ind].sprite->getPosition());
    curr_cell.current_index = vec_field[swap_cell_ind].current_index;

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

Board::Cells::iterator Board::cellByCurrentIndex(Cells::size_type index)
{
    return std::find_if(vec_field.begin(), vec_field.end(), [&](const Cell& cell) { return cell.current_index == index; });
}

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

int Board::Cell::side_length = 0;