<?php

namespace Give\Receipt;

use ArrayAccess;
use Give\Framework\Exceptions\Primitives\InvalidArgumentException;
use Iterator;

/**
 * Class Section
 *
 * This class represent receipt section as object and you can add ass many as you want line items.
 *
 * @package Give\Receipt
 * @since 2.7.0
 */
class Section implements Iterator, ArrayAccess
{
    /**
     * Iterator initial position.
     *
     * @var int
     */
    private $position = 0;

    /**
     * Array of line item ids to use in Iterator.
     * Note: this property helps to iterate over associative array.
     *
     * @var int
     */
    private $lineItemIds = [];

    /**
     * Section heading.
     *
     * @since 2.7.0
     * @var string
     */
    public $label = '';

    /**
     * Section ID.
     *
     * @since 2.7.0
     * @var string
     */
    public $id = '';

    /**
     * Array of detail item class names.
     *
     * @since 2.7.0
     * @var LineItem[]
     */
    private $lineItems = [];

    /**
     * Section constructor.
     *
     * @param string $id
     * @param string $label
     */
    public function __construct($id, $label)
    {
        $this->id = $id;
        $this->label = $label;
    }

    /**
     * Get line items.
     *
     * @since 2.7.0
     * @return LineItem[]
     */
    public function getLineItems()
    {
        return $this->lineItems;
    }

    /**
     * Add detail group.
     *
     * @since 2.7.0
     *
     * @param string $position Position can be set either "before" or "after" to insert line item at specific position.
     * @param string $lineItemId
     *
     * @param array  $lineItem
     *
     * @return LineItem
     */
    public function addLineItem($lineItem, $position = '', $lineItemId = '')
    {
        $this->validateLineItem($lineItem);

        $icon = isset($lineItem['icon']) ? $lineItem['icon'] : '';

        $lineItemObj = new LineItem($lineItem['id'], $lineItem['label'], $lineItem['value'], $icon);

        if (isset($this->lineItems[$lineItemId]) && in_array($position, ['before', 'after'])) {
            // Insert line item at specific position.
            $tmp = [];
            $tmpIds = [];

            foreach ($this->lineItems as $id => $data) {
                if ('after' === $position) {
                    $tmp[$id] = $data;
                    $tmpIds[] = $id;
                }

                if ($id === $lineItemId) {
                    $tmp[$lineItemObj->id] = $lineItemObj;
                    $tmpIds[] = $lineItemObj->id;
                }

                if ('before' === $position) {
                    $tmp[$id] = $data;
                    $tmpIds[] = $id;
                }
            }

            $this->lineItems = $tmp;
            $this->lineItemIds = $tmpIds;
        } else {
            $this->lineItems[$lineItemObj->id] = $lineItemObj;
            $this->lineItemIds[] = $lineItemObj->id;
        }

        return $lineItemObj;
    }

    /**
     * Remove line item.
     *
     * @since 2.7.0
     *
     * @param string $lineItemId
     *
     */
    public function removeLineItem($lineItemId)
    {
        $this->offsetUnset($lineItemId);
    }

    /**
     * Validate line item.
     *
     * @since 2.7.0
     *
     * @param array $array
     *
     */
    protected function validateLineItem($array)
    {
        $required = ['id', 'label', 'value'];
        $array = array_filter($array); // Remove empty values.

        if (array_diff($required, array_keys($array))) {
            throw new InvalidArgumentException(
                esc_html__(
                    'Invalid receipt section line item. Please provide valid line item id, label, and value.',
                    'give'
                )
            );
        }
    }

    /**
     * Return current data.
     *
     * @since 2.7.0
     * @return mixed
     */
    public function current()
    {
        return $this->lineItems[$this->lineItemIds[$this->position]];
    }

    /**
     * Update iterator position.
     *
     * @since 2.7.0
     */
    public function next()
    {
        ++$this->position;
    }

    /**
     * Return iterator position.
     *
     * @since 2.7.0
     * @return int
     */
    public function key()
    {
        return $this->position;
    }

    /**
     * Return whether or not valid array position.
     *
     * @since 2.7.0
     * @return bool|void
     */
    public function valid()
    {
        return isset($this->lineItemIds[$this->position]);
    }

    /**
     * Set iterator position to zero when rewind.
     *
     * @since 2.7.0
     */
    public function rewind()
    {
        $this->position = 0;
    }

    /**
     * Set line item.
     *
     * @since 2.7.0
     *
     * @param array  $value LineItem Data.
     *
     * @param string $offset LineItem ID.
     */
    public function offsetSet($offset, $value)
    {
        $this->addLineItem($value);
    }

    /**
     * Return whether or not line item id exist in line.
     *
     * @since 2.7.0
     *
     * @param string $offset LineItem ID.
     *
     * @return bool
     */
    public function offsetExists($offset)
    {
        return isset($this->lineItems[$offset]);
    }

    /**
     * Remove line item from line.
     *
     * @since 2.7.0
     *
     * @param string $offset LineItem ID.
     *
     */
    public function offsetUnset($offset)
    {
        if ($this->offsetExists($offset)) {
            unset($this->lineItems[$offset]);
            $this->lineItemIds = array_keys($this->lineItems);
        }
    }

    /**
     * Get line item.
     *
     * @since 2.7.0
     *
     * @param string $offset LineItem ID.
     *
     * @return LineItem|null
     */
    public function offsetGet($offset)
    {
        return isset($this->lineItems[$offset]) ? $this->lineItems[$offset] : null;
    }
}