TelegramBot\InlineKeyboardPagination\InlineKeyboardPagination

Complexity

Total Complexity

41

Size/Duplication

Total Lines	315
Duplicated Lines	0 %

Coupling/Cohesion

Components	1
Dependencies	1

Importance

Changes

0

17 Methods

Rating	Name	Duplication	Size	Complexity
A	setMaxButtons()	0	9	3
A	getLabels()	0	4	1
A	setLabels()	0	6	1
A	setCommand()	0	6	1
A	setSelectedPage()	0	10	3
A	getItemsPerPage()	0	4	1
A	setItemsPerPage()	0	9	2
A	setItems()	0	9	2
A	getNumberOfPages()	0	4	1
A	__construct()	0	7	1
A	getPagination()	0	11	2
C	generateKeyboard()	0	50	14
B	generateRange()	0	26	5
A	generateButton()	0	7	1
A	generateCallbackData()	0	4	1
A	getPreparedItems()	0	4	1
A	getOffset()	0	4	1

<?php

namespace TelegramBot\InlineKeyboardPagination;

use TelegramBot\InlineKeyboardPagination\Exceptions\InlineKeyboardPaginationException;

/**
 * Class InlineKeyboardPagination
 *
 * @package TelegramBot\InlineKeyboardPagination
 */
class InlineKeyboardPagination implements InlineKeyboardPaginator
{
    /**
     * @var integer
     */
    private $items_per_page;

    /**
     * @var integer
     */
    private $max_buttons = 5;

    /**
     * @var integer
     */
    private $selected_page;

    /**
     * @var array
     */
    private $items;

    /**
     * @var string
     */
    private $command;

    /**
     * @var array
     */
    private $labels = [
        'default'  => '%d',
        'first'    => '« %d',
        'previous' => '‹ %d',
        'current'  => '· %d ·',
        'next'     => '%d ›',
        'last'     => '%d »',
    ];

    /**
     * @inheritdoc
     * @throws InlineKeyboardPaginationException
     */
    public function setMaxButtons(int $max_buttons = 5): InlineKeyboardPagination
    {
        if ($max_buttons < 5 || $max_buttons > 8) {
            throw new InlineKeyboardPaginationException('Invalid max buttons, must be between 5 and 8.');
        }
        $this->max_buttons = $max_buttons;

        return $this;
    }

    /**
     * Return list of keyboard button labels.
     *
     * @return array
     */
    public function getLabels(): array
    {
        return $this->labels;
    }

    /**
     * Set the keyboard button labels.
     *
     * @param array $labels
     *
     * @return InlineKeyboardPagination
     */
    public function setLabels($labels): InlineKeyboardPagination
    {
        $this->labels = $labels;

        return $this;
    }

    /**
     * @inheritdoc
     */
    public function setCommand(string $command = 'pagination'): InlineKeyboardPagination
    {
        $this->command = $command;

        return $this;
    }

    /**
     * @inheritdoc
     * @throws InlineKeyboardPaginationException
     */
    public function setSelectedPage(int $selected_page): InlineKeyboardPagination
    {
        $number_of_pages = $this->getNumberOfPages();
        if ($selected_page < 1 || $selected_page > $number_of_pages) {
            throw new InlineKeyboardPaginationException('Invalid selected page, must be between 1 and ' . $number_of_pages);
        }
        $this->selected_page = $selected_page;

        return $this;
    }

    /**
     * @return int
     */
    public function getItemsPerPage(): int
    {
        return $this->items_per_page;
    }

    /**
     * @param int $items_per_page
     *
     * @return InlineKeyboardPagination
     * @throws InlineKeyboardPaginationException
     */
    public function setItemsPerPage($items_per_page): InlineKeyboardPagination
    {
        if ($items_per_page <= 0) {
            throw new InlineKeyboardPaginationException('Invalid number of items per page, must be at least 1');
        }
        $this->items_per_page = $items_per_page;

        return $this;
    }

    /**
     * @param array $items
     *
     * @return InlineKeyboardPagination
     * @throws InlineKeyboardPaginationException
     */
    public function setItems(array $items): InlineKeyboardPagination
    {
        if (empty($items)) {
            throw new InlineKeyboardPaginationException('Items list empty.');
        }
        $this->items = $items;

        return $this;
    }

    /**
     * Calculate and return the number of pages.
     *
     * @return int
     */
    public function getNumberOfPages(): int
    {
        return (int) ceil(count($this->items) / $this->items_per_page);
    }

    /**
     * TelegramBotPagination constructor.
     *
     * @inheritdoc
     * @throws InlineKeyboardPaginationException
     */
    public function __construct(array $items, string $command = 'pagination', int $selected_page = 1, int $items_per_page = 5)
    {
        $this->setCommand($command);
        $this->setItemsPerPage($items_per_page);
        $this->setItems($items);
        $this->setSelectedPage($selected_page);
    }

    /**
     * @inheritdoc
     * @throws InlineKeyboardPaginationException
     */
    public function getPagination(int $selected_page = null): array
    {
        if ($selected_page !== null) {
            $this->setSelectedPage($selected_page);
        }

        return [
            'items'    => $this->getPreparedItems(),
            'keyboard' => [$this->generateKeyboard()],
        ];
    }

    /**
     * Generate the keyboard with the correctly labelled buttons.
     *
     * @return array
     */
    protected function generateKeyboard(): array
    {
        $buttons         = [];
        $number_of_pages = $this->getNumberOfPages();

        if ($number_of_pages > $this->max_buttons) {
            $buttons[1] = $this->generateButton(1);

            $range = $this->generateRange();
            for ($i = $range['from']; $i < $range['to']; $i++) {
                $buttons[$i] = $this->generateButton($i);
            }

            $buttons[$number_of_pages] = $this->generateButton($number_of_pages);
        } else {
            for ($i = 1; $i <= $number_of_pages; $i++) {
                $buttons[$i] = $this->generateButton($i);
            }
        }

        // Set the correct labels.
        foreach ($buttons as $page => &$button) {
            $in_first_block = $this->selected_page <= 3 && $page <= 3;
            $in_last_block  = $this->selected_page >= $number_of_pages - 2 && $page >= $number_of_pages - 2;

            $label_key = 'next';
            if ($page === $this->selected_page) {
                $label_key = 'current';
            } elseif ($in_first_block || $in_last_block) {
                $label_key = 'default';
            } elseif ($page === 1) {
                $label_key = 'first';
            } elseif ($page === $number_of_pages) {
                $label_key = 'last';
            } elseif ($page < $this->selected_page) {
                $label_key = 'previous';
            }

            $label = $this->labels[$label_key] ?? '';

            if ($label === '') {
                $button = null;
                continue;
            }

            $button['text'] = sprintf($label, $page);
        }

        return array_filter($buttons);
    }

    /**
     * Get the range of intermediate buttons for the keyboard.
     *
     * @return array
     */
    protected function generateRange(): array
    {
        $number_of_intermediate_buttons = $this->max_buttons - 2;
        $number_of_pages                = $this->getNumberOfPages();

        if ($this->selected_page === 1) {
            $from = 2;
            $to   = $from + $number_of_intermediate_buttons;
        } elseif ($this->selected_page === $number_of_pages) {
            $from = $number_of_pages - $number_of_intermediate_buttons;
            $to   = $number_of_pages;
        } else {
            if (($this->selected_page + $number_of_intermediate_buttons) > $number_of_pages) {
                $from = $number_of_pages - $number_of_intermediate_buttons;
                $to   = $number_of_pages;
            } elseif (($this->selected_page - 2) < 1) {
                $from = $this->selected_page;
                $to   = $this->selected_page + $number_of_intermediate_buttons;
            } else {
                $from = $this->selected_page - 1;
                $to   = $this->selected_page + 2;
            }
        }

        return compact('from', 'to');
    }

    /**
     * Generate the button for the passed page.
     *
     * @param int $page
     *
     * @return array
     */
    protected function generateButton(int $page): array
    {
        return [
            'text'          => (string) $page,
            'callback_data' => $this->generateCallbackData($page),
        ];
    }

    /**
     * Generate the callback data for the passed page.
     *
     * @param int $page
     *
     * @return string
     */
    protected function generateCallbackData(int $page): string
    {
        return "{$this->command}?currentPage={$this->selected_page}&nextPage={$page}";
    }

    /**
     * Get the prepared items for the selected page.
     *
     * @return array
     */
    protected function getPreparedItems(): array
    {
        return array_slice($this->items, $this->getOffset(), $this->items_per_page);
    }

    /**
     * @return int
     */
    protected function getOffset(): int
    {
        return $this->items_per_page * ($this->selected_page - 1);
    }
}