// Calculate sum of all file size displayed on a category page
// © 2025 [[User:RoyZuo]]
// Feedback ☞ [[c:User talk:RoyZuo]]
mw.hook('wikipage.content').add(function($content) {
    // Only run if the namespace is "Category" (wgNamespaceNumber == 14)
    if (mw.config.get('wgNamespaceNumber') === 14) {
        let totalSizeMB = 0;
        let totalFiles = 0;

        // Regex to match file size patterns like '2.56 MB', '500 KB', '2048 bytes', etc.
        let sizeRegex = /(\d+(\.\d+)?)\s*(bytes|KB|MB|GB)/g;

        // Extract and sum all sizes, counting total files
        $content.find("li.gallerybox").each(function() {
            let sizeText = $(this).find("div.gallerytext").text();
            let match;
            while ((match = sizeRegex.exec(sizeText)) !== null) {
                let size = parseFloat(match[1]);
                let unit = match[3].toUpperCase();

                // Convert the size to MB
                if (unit === "BYTES") {
                    size /= (1024 * 1024); // Convert bytes to MB
                } else if (unit === "KB") {
                    size /= 1024; // Convert KB to MB
                } else if (unit === "GB") {
                    size *= 1024; // Convert GB to MB
                }

                totalSizeMB += size;
                totalFiles++; // Count each file
            }
        });

        // Convert total size to the appropriate unit (KB, MB, or GB)
        let totalSize = totalSizeMB;
        let unit = "MB";

        if (totalSize >= 1024) {
            totalSize /= 1024;
            unit = "GB";
        } else if (totalSize < 1) {
            totalSize *= 1024;
            unit = "KB";
        }

        // Handle the case where the total size is exactly 1024 MB, to display it as 1 GB
        if (unit === "MB" && totalSize >= 1024) {
            totalSize /= 1024;
            unit = "GB";
        }

        // Create the message displaying the total files and total size
        let fileWord = totalFiles === 1 ? "file" : "files";
        let totalSizeMessage = `On this page: ${totalSize.toFixed(2)} ${unit} (${totalFiles} ${fileWord})`;

        // Create a paragraph element with the message
        let totalSizeElement = $("<p>").text(totalSizeMessage).css({
        	"font-size": "16px"
        });
        // Insert the message as the last element inside <h1 id="firstHeading">
        $("#firstHeading").append(totalSizeElement);
    }
});