<?php

namespace Kirby\Parsley\Schema;

use Kirby\Parsley\Element;
use Kirby\Toolkit\Str;

/**
 * The plain schema definition converts
 * the entire document into simple text blocks
 *
 * @since 3.5.0
 *
 * @package   Kirby Parsley
 * @author    Bastian Allgeier <bastian@getkirby.com>,
 * @link      https://getkirby.com
 * @copyright Bastian Allgeier GmbH
 * @license   https://getkirby.com/license
 */
class Blocks extends Plain
{
    /**
     * @param \Kirby\Parsley\Element $node
     * @return array
     */
    public function blockquote(Element $node): array
    {
        $citation = null;
        $text     = [];

        // get all the text for the quote
        foreach ($node->children() as $child) {
            if (is_a($child, 'DOMText') === true) {
                $text[] = trim($child->textContent);
            }
            if (is_a($child, 'DOMElement') === true && $child->tagName !== 'footer') {
                $text[] = (new Element($child))->innerHTML($this->marks());
            }
        }

        // filter empty blocks and separate text blocks with breaks
        $text = implode('', array_filter($text));

        // get the citation from the footer
        if ($footer = $node->find('footer')) {
            $citation = $footer->innerHTML($this->marks());
        }

        return [
            'content' => [
                'citation' => $citation,
                'text'     => $text
            ],
            'type' => 'quote',
        ];
    }

    /**
     * Creates the fallback block type
     * if no other block can be found
     *
     * @param \Kirby\Parsley\Element|string $element
     * @return array|null
     */
    public function fallback($element): ?array
    {
        if (is_a($element, Element::class) === true) {
            $html = $element->innerHtml();

            // wrap the inner HTML in a p tag if it doesn't
            // contain one yet.
            if (Str::contains($html, '<p>') === false) {
                $html = '<p>' . $html . '</p>';
            }
        } elseif (is_string($element) === true) {
            $html = trim($element);

            if (Str::length($html) === 0) {
                return null;
            }

            $html = '<p>' . $html . '</p>';
        } else {
            return null;
        }

        return [
            'content' => [
                'text' => $html,
            ],
            'type' => 'text',
        ];
    }

    /**
     * Converts a heading element to a heading block
     *
     * @param \Kirby\Parsley\Element $node
     * @return array
     */
    public function heading(Element $node): array
    {
        $content = [
            'level' => strtolower($node->tagName()),
            'text'  => $node->innerHTML()
        ];

        if ($id = $node->attr('id')) {
            $content['id'] = $id;
        }

        ksort($content);

        return [
            'content' => $content,
            'type'    => 'heading',
        ];
    }

    /**
     * @param \Kirby\Parsley\Element $node
     * @return array
     */
    public function iframe(Element $node): array
    {
        $caption = null;
        $src     = $node->attr('src');

        if ($figcaption = $node->find('ancestor::figure[1]//figcaption')) {
            $caption = $figcaption->innerHTML($this->marks());

            // avoid parsing the caption twice
            $figcaption->remove();
        }

        // reverse engineer video URLs
        if (preg_match('!player.vimeo.com\/video\/([0-9]+)!i', $src, $array) === 1) {
            $src = 'https://vimeo.com/' . $array[1];
        } elseif (preg_match('!youtube.com\/embed\/([a-zA-Z0-9_-]+)!', $src, $array) === 1) {
            $src = 'https://youtube.com/watch?v=' . $array[1];
        } elseif (preg_match('!youtube-nocookie.com\/embed\/([a-zA-Z0-9_-]+)!', $src, $array) === 1) {
            $src = 'https://youtube.com/watch?v=' . $array[1];
        } else {
            $src = false;
        }

        // correct video URL
        if ($src) {
            return [
                'content' => [
                    'caption' => $caption,
                    'url'     => $src
                ],
                'type' => 'video',
            ];
        }

        return [
            'content' => [
                'text' => $node->outerHTML()
            ],
            'type' => 'markdown',
        ];
    }

    /**
     * @param \Kirby\Parsley\Element $node
     * @return array
     */
    public function img(Element $node): array
    {
        $caption = null;
        $link = null;

        if ($figcaption = $node->find('ancestor::figure[1]//figcaption')) {
            $caption = $figcaption->innerHTML($this->marks());

            // avoid parsing the caption twice
            $figcaption->remove();
        }

        if ($a = $node->find('ancestor::a')) {
            $link = $a->attr('href');
        }

        return [
            'content' => [
                'alt'      => $node->attr('alt'),
                'caption'  => $caption,
                'link'     => $link,
                'location' => 'web',
                'src'      => $node->attr('src'),
            ],
            'type' => 'image',
        ];
    }

    /**
     * Converts a list element to HTML
     *
     * @param \Kirby\Parsley\Element $node
     * @return string
     */
    public function list(Element $node): string
    {
        $html = [];

        foreach ($node->filter('li') as $li) {
            $innerHtml = '';

            foreach ($li->children() as $child) {
                if (is_a($child, 'DOMText') === true) {
                    $innerHtml .= $child->textContent;
                } elseif (is_a($child, 'DOMElement') === true) {
                    $child = new Element($child);

                    if (in_array($child->tagName(), ['ul', 'ol']) === true) {
                        $innerHtml .= $this->list($child);
                    } else {
                        $innerHtml .= $child->innerHTML($this->marks());
                    }
                }
            }

            $html[] = '<li>' . trim($innerHtml) . '</li>';
        }

        return '<' . $node->tagName() . '>' . implode($html) . '</' . $node->tagName() . '>';
    }

    /**
     * Returns a list of allowed inline marks
     * and their parsing rules
     *
     * @return array
     */
    public function marks(): array
    {
        return [
            [
                'tag' => 'a',
                'attrs' => ['href', 'rel', 'target', 'title'],
                'defaults' => [
                    'rel' => 'noopener noreferrer'
                ]
            ],
            [
                'tag' => 'abbr',
            ],
            [
                'tag' => 'b'
            ],
            [
                'tag' => 'br',
            ],
            [
                'tag' => 'code'
            ],
            [
                'tag' => 'del',
            ],
            [
                'tag' => 'em',
            ],
            [
                'tag' => 'i',
            ],
            [
                'tag' => 'p',
            ],
            [
                'tag' => 'strike',
            ],
            [
                'tag' => 'sub',
            ],
            [
                'tag' => 'sup',
            ],
            [
                'tag' => 'strong',
            ],
            [
                'tag' => 'u',
            ],
        ];
    }

    /**
     * Returns a list of allowed nodes and
     * their parsing rules
     *
     * @codeCoverageIgnore
     * @return array
     */
    public function nodes(): array
    {
        return [
            [
                'tag' => 'blockquote',
                'parse' => function (Element $node) {
                    return $this->blockquote($node);
                }
            ],
            [
                'tag' => 'h1',
                'parse' => function (Element $node) {
                    return $this->heading($node);
                }
            ],
            [
                'tag' => 'h2',
                'parse' => function (Element $node) {
                    return $this->heading($node);
                }
            ],
            [
                'tag' => 'h3',
                'parse' => function (Element $node) {
                    return $this->heading($node);
                }
            ],
            [
                'tag' => 'h4',
                'parse' => function (Element $node) {
                    return $this->heading($node);
                }
            ],
            [
                'tag' => 'h5',
                'parse' => function (Element $node) {
                    return $this->heading($node);
                }
            ],
            [
                'tag' => 'h6',
                'parse' => function (Element $node) {
                    return $this->heading($node);
                }
            ],
            [
                'tag' => 'hr',
                'parse' => function (Element $node) {
                    return [
                        'type' => 'line'
                    ];
                }
            ],
            [
                'tag' => 'iframe',
                'parse' => function (Element $node) {
                    return $this->iframe($node);
                }
            ],
            [
                'tag' => 'img',
                'parse' => function (Element $node) {
                    return $this->img($node);
                }
            ],
            [
                'tag' => 'ol',
                'parse' => function (Element $node) {
                    return [
                        'content' => [
                            'text' => $this->list($node)
                        ],
                        'type' => 'list',
                    ];
                }
            ],
            [
                'tag'   => 'pre',
                'parse' => function (Element $node) {
                    return $this->pre($node);
                }
            ],
            [
                'tag' => 'table',
                'parse' => function (Element $node) {
                    return $this->table($node);
                }
            ],
            [
                'tag' => 'ul',
                'parse' => function (Element $node) {
                    return [
                        'content' => [
                            'text' => $this->list($node)
                        ],
                        'type' => 'list',
                    ];
                }
            ],
        ];
    }

    /**
     * @param \Kirby\Parsley\Element $node
     * @return array
     */
    public function pre(Element $node): array
    {
        $language = 'text';

        if ($code = $node->find('//code')) {
            foreach ($code->classList() as $className) {
                if (preg_match('!language-(.*?)!', $className)) {
                    $language = str_replace('language-', '', $className);
                    break;
                }
            }
        }

        return [
            'content' => [
                'code'     => $node->innerText(),
                'language' => $language
            ],
            'type' => 'code',
        ];
    }

    /**
     * @param \Kirby\Parsley\Element $node
     * @return array
     */
    public function table(Element $node): array
    {
        return [
            'content' => [
                'text' => $node->outerHTML(),
            ],
            'type' => 'markdown',
        ];
    }
}