<?php

namespace App\Game;

class GameBoardState
{
    /**
     * Cell states. (unset is default state)
     */
    const STATE_PRESSED = 0;
    const STATE_WIN     = 1;

    /**
     * Width of the board
     */
    protected int $width;

    /**
     * Height of the board
     */
    protected int $height;

    /**
     * State of the cells.
     */
    protected array $state = [];

    /**
     * If the board is in a winning state or not.
     */
    protected  int $winning = 0;

    /**
     * Constructor
     */
    public function __construct($width, $height)
    {
        $this->width = $width;
        $this->height = $height;
    }

    /**
     * Set the state of a cell.
     */
    public function set(int $pos, bool $pressed = true) : self
    {
        if ($this->hasGameEnded()) {
            return $this;
        }

        if ($pressed) {
            $this->state[$pos] = self::STATE_PRESSED;
        } else {
            unset($this->state[$pos]);
        }

        $this->update();

        return $this;
    }

    /**
     * Toggle pressed state of a cell.
     */
    public function toggle(int $pos) : self
    {
        return $this->set($pos, !$this->isPressed($pos));
    }

    /**
     * Check if a cell is pressed or not.
     */
    public function isPressed(int $pos) : bool
    {
        return isset($this->state[$pos]);
    }

    /**
     * Check if a cell is part of a winning row/column.
     */
    public function isWin(int $pos) : bool
    {
        return isset($this->state[$pos]) && $this->state[$pos] == self::STATE_WIN;
    }

    /**
     * Get the sate of the cells.
     */
    public function getState() : array
    {
        return $this->state;
    }

    /**
     * Get the size of the board.
     */
    public function getSize() : int
    {
        return $this->width * $this->height;
    }

    /**
     * Clear the board.
     */
    public function clear() : self
    {
        $this->state = [];
        $this->winning = 0;
        return $this;
    }

    // TODO: Rename
    public function getNumWinRows() : int
    {
        return $this->winning;
    }

    /**
     * Check if the board only has winning cards
     */
    public function hasGameEnded() : bool
    {
        if (count($this->state) < $this->width * $this->height) {
            return false;
        }

        foreach($this->state as $pos) {
            if ($pos !== self::STATE_WIN) {
                return false;
            }
        }
        return true;
    }

    /**
     * Check if the board is full and all positions is in a given state.
     */
    public function isFull($state) : bool
    {
        // Board not filled, impossible to have all positions set.
        if (count($this->state) < $this->width * $this->height) {
            return false;
        }

        foreach($this->state as $pos) {
            if ($pos !== $state) {
                return false;
            }
        }
        return true;
    }

    /**
     *
     */
    protected function update()
    {
        foreach($this->state as $pos => $_) {
            $this->state[$pos] = self::STATE_PRESSED;
        }

        $patterns = $this->checkWinningState();
        foreach($patterns as $cards) {
            foreach($cards as $pos) {
                $this->state[$pos] = self::STATE_WIN;
            }
        }
        $this->winning = count($patterns);
    }

    /**
     * Check if the board is in a winning state.
     */
    protected function checkWinningState() : array
    {
        $win = [];

        // Rows
        for($y=0; $y < $this->height; $y++) {
            $c = $this->checkRow($y);
            if (count($c)) {
                $win[] = $c;
            }
        }

        // Columns
        for($x=0; $x < $this->width; $x++) {
            $c = $this->checkCol($x);
            if (count($c)) {
                $win[] = $c;
            }
        }

        return $win;
    }

    /**
     * Check if a row is in a winning state (all cells pressed)
     */
    protected function checkRow($y) : array
    {
        $cards = [];

        $y = $y * $this->width;
        for($x = 0; $x < $this->width; $x++) {
            $pos = $x + $y;
            if (!$this->isPressed($pos)) {
                return [];
            }
            /*
            if ($this->state[$pos] == self::STATE_WIN) {
                continue;
            } */
            $cards[] = $pos;
        }

        return $cards;
    }

    /**
     * Check if a column is in a winning state (all cells pressed)
     */
    protected function checkCol($x) : array
    {
        $cards = [];

        for($y = 0; $y < $this->height; $y++) {
            $pos = $x + ($y * $this->width);
            if (!$this->isPressed($pos)) {
                return [];
            }
            /*
            if ($this->state[$pos] == self::STATE_WIN) {
                continue;
            } */
            $cards[] = $pos;
        }

        return $cards;
    }
}