footnotes/includes/replacer.php

<?php
/**
 * Created by Stefan Herndler.
 * User: Stefan
 * Date: 15.05.14
 * Time: 16:21
 * Version: 1.0.7
 * Since: 1.0
 */

/*
 * collection of all footnotes found on the current page
 * @since 1.0
 */
$g_arr_Footnotes = array();

/*
 * collection of all footnotes settings
 * @since 1.0-beta
 */
$g_arr_FootnotesSettings = array();

/*
 * flag to know if the replacement already started for the current page
 * @since 1.0.7
 */
$g_bool_FootnotesReplacementStarted = false;

/**
 * register all functions needed for the replacement in the wordpress core
 * @since 1.0-gamma
 */
function footnotes_RegisterReplacementFunctions()
{
    /* access to the global settings collection */
    global $g_arr_FootnotesSettings;
    /* load footnote settings */
    $g_arr_FootnotesSettings = footnotes_filter_options(FOOTNOTE_SETTINGS_CONTAINER, Class_FootnotesSettings::$a_arr_Default_Settings, false);

    /* starts listening to the output for replacement */
    add_action('wp_head', 'footnotes_startReplacing');
    /* stops listening to the output and replaces the footnotes */
    add_action('get_footer', 'footnotes_StopReplacing');

    /* moves these contents through the replacement function */
    add_filter('the_content', 'footnotes_Replacer_Content');
    add_filter('the_excerpt', 'footnotes_Replacer_Excerpt');
    add_filter('widget_title', 'footnotes_Replacer_WidgetTitle');
    add_filter('widget_text', 'footnotes_Replacer_WidgetText');

    /* adds the love and share me slug to the footer */
    add_filter('wp_footer', 'footnotes_LoveAndShareMe');

}

/**
 * replacement action for the_excerpt
 * @param string $p_str_Content
 * @return string
 * @since 1.0.7
 */
function footnotes_Replacer_Content($p_str_Content)
{
    /* access to the global settings collection */
    global $g_arr_FootnotesSettings;
    /* get setting for 'display reference container position' */
    $l_str_ReferenceContainerPosition = $g_arr_FootnotesSettings[FOOTNOTE_INPUTFIELD_SEARCH_IN_EXCERPT];
    /* check if reference container should be displayed at the end of a post */
    if ($l_str_ReferenceContainerPosition == "post_end") {
        footnotes_StopReplacing();
        footnotes_startReplacing();
    }
    /* returns content */
    return $p_str_Content;
}

/**
 * replacement action for the_excerpt
 * @param string $p_str_Content
 * @return string
 * @since 1.0.7
 */
function footnotes_Replacer_Excerpt($p_str_Content)
{
    /* access to the global settings collection */
    global $g_arr_FootnotesSettings;
    /* get setting for accepting footnotes in the excerpt and convert it to boolean */
    $l_bool_SearchExcerpt = footnotes_ConvertToBool($g_arr_FootnotesSettings[FOOTNOTE_INPUTFIELD_SEARCH_IN_EXCERPT]);
    /* search in the excerpt only if activated */
    if ($l_bool_SearchExcerpt) {
        footnotes_StopReplacing();
        footnotes_startReplacing();
    }
    /* returns content */
    return $p_str_Content;
}

/**
 * replacement action for widget_title
 * @param string $p_str_Content
 * @return string
 * @since 1.0.7
 */
function footnotes_Replacer_WidgetTitle($p_str_Content)
{
    /* returns content */
    return $p_str_Content;
}

/**
 * replacement action for widget_text
 * @param string $p_str_Content
 * @return string
 * @since 1.0.7
 */
function footnotes_Replacer_WidgetText($p_str_Content)
{
    /* returns content */
    return $p_str_Content;
}

/**
 * starts listening for footnotes to be replaced
 * output will be buffered and not displayed
 * @since 1.0
 * added flag to only start 'stopping output' once in version 1.0.7
 */
function footnotes_startReplacing()
{
    /* global access to the replacement flag */
    global $g_bool_FootnotesReplacementStarted;
    /* stop output if flag is not set yet */
    if (!$g_bool_FootnotesReplacementStarted) {
        /* stop the output and move it to a buffer instead, defines a callback function */
        ob_start("footnotes_replaceFootnotes");
        /* set flag to only start stopping the output once */
        $g_bool_FootnotesReplacementStarted = true;
    }
}

/**
 * stops buffering the output, automatically calls the ob_start() defined callback function
 * replaces all footnotes in the whole buffer and outputs it
 * @since 1.0
 * cleared the flag in version 1.0.7
 */
function footnotes_StopReplacing()
{
    /* global access to the replacement flag */
    global $g_bool_FootnotesReplacementStarted;
    /* un-set the flag as soon as the replacement function stops and the content will be displayed */
    $g_bool_FootnotesReplacementStarted = false;
    /* calls the callback function defined in ob_start(); */
    ob_end_flush();
}

/**
 * outputs a link to love and share this awesome plugin
 * @since 1.0-gamma
 */
function footnotes_LoveAndShareMe()
{
    /* access to the global settings collection */
    global $g_arr_FootnotesSettings;
    /*
     * updated url to wordpress.org plugin page instead of the github page
     * also updated the font-style and translation the string "footnotes"
     * in version 1.0.6
     */
    /*
     * changed replacement of public plugin name to use global styling setting
     * @since 1.0.7
     */
    /* get setting for love and share this plugin and convert it to boolean */
    $l_bool_LoveMe = footnotes_ConvertToBool($g_arr_FootnotesSettings[FOOTNOTE_INPUTFIELD_LOVE]);
    /* check if the admin allows to add a link to the footer */
    if ($l_bool_LoveMe) {
        echo '
		<div style="text-align:center; color:#acacac;">' .
            sprintf(__("Hey there, I'm using the awesome WordPress Plugin called %s", FOOTNOTES_PLUGIN_NAME), '<a href="http://wordpress.org/plugins/footnotes/" target="_blank" style="text-decoration: none;">' . FOOTNOTES_PLUGIN_PUBLIC_NAME . '</a>') .
            '</div>';
    }
}

/**
 * replaces all footnotes in the given content
 * loading settings if not happened yet since 1.0-gamma
 * @since 1.0
 * @param string $p_str_Content
 * @param bool $p_bool_OutputReferences [default: true]
 * @param bool $p_bool_ReplaceHtmlChars [ default: false]
 * @return string
 */
function footnotes_replaceFootnotes($p_str_Content, $p_bool_OutputReferences = true, $p_bool_ReplaceHtmlChars = false)
{
    /* get access to the global array */
    global $g_arr_Footnotes;
    /* access to the global settings collection */
    global $g_arr_FootnotesSettings;
    /* load footnote settings */
    $g_arr_FootnotesSettings = footnotes_filter_options(FOOTNOTE_SETTINGS_CONTAINER, Class_FootnotesSettings::$a_arr_Default_Settings, $p_bool_ReplaceHtmlChars);
    /* replace all footnotes in the content */
    $p_str_Content = footnotes_getFromString($p_str_Content);

    /* add the reference list if set */
    if ($p_bool_OutputReferences) {
        $p_str_Content = $p_str_Content . footnotes_OutputReferenceContainer();
        /* free all found footnotes if reference container will be displayed */
        $g_arr_Footnotes = array();
    }
    /* return the replaced content */
    return $p_str_Content;
}

/**
 * replace all footnotes in the given string and adds them to an array
 * using a personal starting and ending tag for the footnotes since 1.0-gamma
 * @since 1.0
 * @param string $p_str_Content
 * @return string
 */
function footnotes_getFromString($p_str_Content)
{
    /* get access to the global array to store footnotes */
    global $g_arr_Footnotes;
    /* access to the global settings collection */
    global $g_arr_FootnotesSettings;
    /* contains the index for the next footnote on this page */
    $l_int_FootnoteIndex = 1;
    /* contains the starting position for the lookup of a footnote */
    $l_int_PosStart = 0;
    /* contains the footnote template */
    $l_str_FootnoteTemplate = file_get_contents(FOOTNOTES_TEMPLATES_DIR . "footnote.html");
    /* get footnote starting tag */
    $l_str_StartingTag = $g_arr_FootnotesSettings[FOOTNOTE_INPUTFIELD_PLACEHOLDER_START];
    /*get footnote ending tag */
    $l_str_EndingTag = $g_arr_FootnotesSettings[FOOTNOTE_INPUTFIELD_PLACEHOLDER_END];
    /*get footnote counter style */
    $l_str_CounterStyle = $g_arr_FootnotesSettings[FOOTNOTE_INPUTFIELD_COUNTER_STYLE];

    /* check for a footnote placeholder in the current page */
    do {
        /* get first occurence of a footnote starting tag */
        $l_int_PosStart = strpos($p_str_Content, $l_str_StartingTag, $l_int_PosStart);
        /* tag found */
        if ($l_int_PosStart !== false) {
            /* get first occurence of a footnote ending tag after the starting tag */
            $l_int_PosEnd = strpos($p_str_Content, $l_str_EndingTag, $l_int_PosStart);
            /* tag found */
            if ($l_int_PosEnd !== false) {
                /* get length of footnote text */
                $l_int_Length = $l_int_PosEnd - $l_int_PosStart;
                /* get text inside footnote */
                $l_str_FootnoteText = substr($p_str_Content, $l_int_PosStart + strlen($l_str_StartingTag), $l_int_Length - strlen($l_str_StartingTag));
                /* set replacer for the footnote */
                $l_str_ReplaceText = str_replace("[[FOOTNOTE INDEX]]", footnote_convert_index($l_int_FootnoteIndex, $l_str_CounterStyle), $l_str_FootnoteTemplate);
                $l_str_ReplaceText = str_replace("[[FOOTNOTE TEXT]]", $l_str_FootnoteText, $l_str_ReplaceText);
                /* replace footnote in content */
                $p_str_Content = substr_replace($p_str_Content, $l_str_ReplaceText, $l_int_PosStart, $l_int_Length + strlen($l_str_EndingTag));
                /* set footnote to the output box at the end */
                $g_arr_Footnotes[] = $l_str_FootnoteText;
                /* increase footnote index */
                $l_int_FootnoteIndex++;
                /* add offset to the new starting position */
                $l_int_PosStart += ($l_int_PosEnd - $l_int_PosStart);
                /* no ending tag found */
            } else {
                $l_int_PosStart++;
            }
            /* no starting tag found */
        } else {
            break;
        }
    } while (true);

    /* return content */
    return $p_str_Content;
}

/**
 * looks through all footnotes that has been replaced in the current content and
 * adds a reference to the footnote at the end of the content
 * function to collapse the reference container since 1.0-beta
 * @since 1.0
 * @return string
 */
function footnotes_OutputReferenceContainer()
{
    /* get access to the global array to read footnotes */
    global $g_arr_Footnotes;
    /* access to the global settings collection */
    global $g_arr_FootnotesSettings;

    /* no footnotes has been replaced on this page */
    if (empty($g_arr_Footnotes)) {
        /* return empty string */
        return "";
    }

    /* get setting for combine identical footnotes and convert it to boolean */
    $l_bool_CombineIdentical = footnotes_ConvertToBool($g_arr_FootnotesSettings[FOOTNOTE_INPUTFIELD_COMBINE_IDENTICAL]);
    /* get setting for preferences label */
    $l_str_ReferencesLabel = $g_arr_FootnotesSettings[FOOTNOTE_INPUTFIELD_REFERENCES_LABEL];
    /* get setting for collapse reference footnotes and convert it to boolean */
    $l_bool_CollapseReference = footnotes_ConvertToBool($g_arr_FootnotesSettings[FOOTNOTE_INPUTFIELD_COLLAPSE_REFERENCES]);
    /*get footnote counter style */
    $l_str_CounterStyle = $g_arr_FootnotesSettings[FOOTNOTE_INPUTFIELD_COUNTER_STYLE];

    /* output string, prepare it with the reference label as headline */
    $l_str_Output = '<div class="footnote_container_prepare"><p><span onclick="footnote_expand_reference_container(\"\");">' . $l_str_ReferencesLabel . '</span></p></div>';
    /* add a box around the footnotes */
    $l_str_Output .= '<div id="' . FOOTNOTE_REFERENCES_CONTAINER_ID . '"';
    /* add class to hide the references by default, if the user wants it */
    if ($l_bool_CollapseReference) {
        $l_str_Output .= ' class="footnote_hide_box"';
    }
    $l_str_Output .= '>';

    /* contains the footnote template */
    $l_str_FootnoteTemplate = file_get_contents(FOOTNOTES_TEMPLATES_DIR . "container.html");

    /* loop through all footnotes found in the page */
    for ($l_str_Index = 0; $l_str_Index < count($g_arr_Footnotes); $l_str_Index++) {
        /* get footnote text */
        $l_str_FootnoteText = $g_arr_Footnotes[$l_str_Index];
        /* if fottnote is empty, get to the next one */
        if (empty($l_str_FootnoteText)) {
            continue;
        }
        /* get footnote index */
        $l_str_FirstFootnoteIndex = ($l_str_Index + 1);
        $l_str_FootnoteIndex = footnote_convert_index(($l_str_Index + 1), $l_str_CounterStyle);

        /* check if it isn't the last footnote in the array */
        if ($l_str_FirstFootnoteIndex < count($g_arr_Footnotes) && $l_bool_CombineIdentical) {
            /* get all footnotes that I haven't passed yet */
            for ($l_str_CheckIndex = $l_str_FirstFootnoteIndex; $l_str_CheckIndex < count($g_arr_Footnotes); $l_str_CheckIndex++) {
                /* check if a further footnote is the same as the actual one */
                if ($l_str_FootnoteText == $g_arr_Footnotes[$l_str_CheckIndex]) {
                    /* set the further footnote as empty so it won't be displayed later */
                    $g_arr_Footnotes[$l_str_CheckIndex] = "";
                    /* add the footnote index to the actual index */
                    $l_str_FootnoteIndex .= ", " . footnote_convert_index(($l_str_CheckIndex + 1), $l_str_CounterStyle);
                }
            }
        }

        /* add the footnote to the output box */
        /*
         * added function to convert the counter style in the reference container (bugfix for the link to the footnote) in version 1.0.6
         */
        $l_str_ReplaceText = str_replace("[[FOOTNOTE INDEX SHORT]]", footnote_convert_index($l_str_FirstFootnoteIndex, $l_str_CounterStyle), $l_str_FootnoteTemplate);
        $l_str_ReplaceText = str_replace("[[FOOTNOTE INDEX]]", $l_str_FootnoteIndex, $l_str_ReplaceText);
        $l_str_ReplaceText = str_replace("[[FOOTNOTE TEXT]]", $l_str_FootnoteText, $l_str_ReplaceText);
        /* add the footnote container to the output */
        $l_str_Output = $l_str_Output . $l_str_ReplaceText;
    }
    /* add closing tag for the div of the references container */
    $l_str_Output = $l_str_Output . '</div>';
    /* add a javascript to expand the reference container when clicking on a footnote or the reference label */
    $l_str_Output .= '
		<script type="text/javascript">
			function footnote_expand_reference_container(p_str_ID) {
				jQuery("#' . FOOTNOTE_REFERENCES_CONTAINER_ID . '").show();
				if (p_str_ID.length > 0) {
					jQuery(p_str_ID).focus();
				}
			}
		</script>
	';

    /* return the output string */
    return $l_str_Output;
}