<?php

namespace RtfHtmlPhp;

class Group extends Element
{
    public $parent;
    public $children;

    /**
     * Create a new Group, with no parent and no children.
     */
    public function __construct()
    {
        $this->parent = null;
        $this->children = [];
    }

    /**
     * Returns group type
     *
     * @return string|null
     */
    public function getType()
    {
        // No children? Then the group type is null.
        if (count($this->children) == 0) {
            return null;
        }

        $child = $this->children[0];

        // If the first child is a control word, then
        // the group type is the word.
        if ($child instanceof ControlWord) {
            return $child->word;
        }

        // If the first child is a control symbol, then
        // the group type is * for a special symbol, or null.
        if ($child instanceof ControlSymbol) {
            return ($child->symbol == '*') ? '*' : null;
        }

        // If first child is neither word nor symbol, then
        // group type is null.
        return null;
    }

    /**
     * If a group contains a '*' symbol as its first child,
     * then it is a destination group.
     *
     * @return bool|null Group destination
     */
    public function isDestination()
    {
        // If group has no children, then destination is null.
        if (count($this->children) == 0) {
            return null;
        }

        $child = $this->children[0];

        // First child not a control symbol?
        if (!$child instanceof ControlSymbol) {
            return null;
        }

        return $child->symbol == '*';
    }

    /**
     * Returns string representation of the object for debug purposes
     *
     * @param int $level Indentation level
     *
     * @return string
     */
    public function toString($level = 0)
    {
        $str = str_repeat("  ", $level) .  "{\n";

        foreach ($this->children as $child) {
            /*
            // Skip some group types:
            if ($child instanceof Group) {
                if ($child->GetType() == "fonttbl") continue;
                if ($child->GetType() == "colortbl") continue;
                if ($child->GetType() == "stylesheet") continue;
                if ($child->GetType() == "info") continue;
                // Skip any pictures:
                if (substr($child->GetType(), 0, 4) == "pict") continue;
                if ($child->IsDestination()) continue;
            }
            */
            $str .= $child->toString($level + 1);
        }

        return $str . str_repeat("  ", $level) . "}\n";
    }
}