/* eslint no-param-reassign: ["error", { "props": true, "ignorePropertyModificationsFor": ["w"] }] */
// ESLint configuration that prevents reassigning function parameters except for "w" (window)

/* global QRCode */
// Informs ESLint that QRCode is a global variable that will be available at runtime

(function iefe(w, d, c, t, a, s) {
    // Immediately Invoked Function Expression (IIFE) to create a private scope
    // Parameters are shortcuts to commonly used objects/methods:
    // w = window, d = document, c = createElement, t = createTextNode
    // a = appendChild, s = setAttribute

    /* inject:js */
    /* endinject */
    // Placeholder comments for a build process to inject additional JavaScript

    w.printlinks = function printlinks(sel) {
        // Defines a global function on the window object called "printlinks"
        // Takes an optional selector parameter (sel)

        d.querySelectorAll('.tw-linklist,.tw-linkref').forEach((e) => {
            e.remove();
        });
        // First removes any existing link lists or references from previous runs

        const links = d.querySelectorAll(sel || 'a[href]:not([href^="javascript:"])');
        // Selects all links matching the provided selector, or if none provided,
        // selects all <a> elements with href attributes that don't start with "javascript:"

        if (links.length) {
            // Only proceeds if links were found
            
            const dimension = 36;
            // Sets the size for QR codes (36x36)
            
            const hrefs = new Map();
            // Creates a Map to store unique URLs and their reference numbers
            
            const linklist = d[c]('ol');
            // Creates an ordered list element
            
            linklist.className = 'tw-linklist';
            // Assigns a class name for styling and later identification
            
            links.forEach((l) => {
                // Processes each link element
                
                const href = String(l.href);
                // Gets the URL and ensures it's a string
                
                let sup = hrefs.size + 1;
                // Default superscript number if this is a new URL
                
                if (hrefs.has(href)) {
                    // If this URL was already processed
                    sup = hrefs.get(href);
                    // Reuse the existing reference number
                } else {
                    // For new URLs not seen before
                    hrefs.set(href, sup);
                    // Store the URL with its reference number
                    
                    const listitem = d[c]('li');
                    // Create a list item for this URL
                    
                    const qrcode = d.createElementNS('http://www.w3.org/2000/svg', 'svg');
                    // Create an SVG element for the QR code using proper namespace
                    
                    qrcode[s]('width', dimension);
                    qrcode[s]('height', dimension);
                    qrcode[s]('viewBox', `0 0 ${dimension} ${dimension}`);
                    qrcode[s]('aria-hidden', 'true');
                    qrcode[s]('focusable', 'false');
                    // Set SVG attributes for size, accessibility, etc.
                    
                    qrcode.innerHTML = (new QRCode({
                        content: href,       // URL to encode
                        width: dimension,    // Width of QR code
                        height: dimension,   // Height of QR code
                        join: true,          // Join paths into a single path
                        xmlDeclaration: false, // Skip XML declaration
                        ecl: 'L',            // Error correction level: Low
                        container: 'none'    // Don't wrap in a container
                    })).svg();
                    // Generate the QR code SVG and insert it
                    
                    listitem[a](qrcode);
                    // Add QR code to list item
                    
                    listitem[a](d[t](href));
                    // Add URL text to list item
                    
                    linklist[a](listitem);
                    // Add the list item to the ordered list
                }
                
                const ref = d[c]('sup');
                // Create a superscript element for the reference number
                
                ref.className = 'tw-linkref';
                // Assign class for styling and identification
                
                ref[a](d[t](sup));
                // Add the reference number to the superscript
                
                l.parentNode.insertBefore(ref, l.nextSibling);
                // Insert the superscript right after the link
            });
            
            d.body[a](linklist);
            // Add the completed ordered list to the end of the document body
        }
    };
}(window, document, 'createElement', 'createTextNode', 'appendChild', 'setAttribute'));
// Immediately invoke the function with these arguments