Script check each page

This is as far as I got with the code - when i got into trouble I tried flushing it through ChatGPT and Gemini - but neither could resolve the issue or figure out why it's not working. 

This is literally where I have left off. 

#targetengine "textVariableCheckEngine"

(function () {
    var enableEventListener = false; // Set true later if you want automatic check on save

    if (enableEventListener) {
        var handlerAlreadyAdded = true;
        for (var i = 0; i < app.eventListeners.length; i++) {
            if (app.eventListeners[i].name === "textVariableCheckHandler") {
                handlerAlreadyAdded = true;
                break;
            }
        }
        if (!handlerAlreadyAdded) {
            var el = app.addEventListener("beforeSave", textVariableCheck, false);
            el.name = "textVariableCheckHandler";
        }
    }

    textVariableCheck(); // Run immediately for manual test

    function textVariableCheck() {
        try {
            if (app.documents.length === 0) return;

            var doc = app.activeDocument;
            var usedVariables = [];

            // --- Scan pages and master spreads ---
            function scanContainer(container) {
                for (var p = 0; p < container.length; p++) {
                    var page = container[p];
                    var pageItems = page.allPageItems;
                    for (var i = 0; i < pageItems.length; i++) {
                        var item = pageItems[i];
                        if (item.hasOwnProperty("textVariableInstances")) {
                            var instances = item.textVariableInstances;
                            for (var j = 0; j < instances.length; j++) {
                                var v = instances[j];
                                if (v && v.associatedTextVariable && v.associatedTextVariable.name != null) {
                                    var nameStr = String(v.associatedTextVariable.name);
                                    // Classic loop duplicate check
                                    var alreadyAdded = false;
                                    for (var k = 0; k < usedVariables.length; k++) {
                                        if (usedVariables[k] === nameStr) {
                                            alreadyAdded = true;
                                            break;
                                        }
                                    }
                                    if (!alreadyAdded) usedVariables.push(nameStr);
                                }
                            }
                        }
                    }
                }
            }

            scanContainer(doc.pages);
            scanContainer(doc.masterSpreads);

            if (usedVariables.length === 0) {
                alert("⚠ No text variables found in pages or master pages.");
            }

            // --- Code Layer check ---
            var fileName = doc.name.replace(/\.[^\.]+$/, "");
            var techMismatch = false;
            var techFound = false;

            for (var t = 0; t < doc.textFrames.length; t++) {
                var tf = doc.textFrames[t];
                if (tf.itemLayer && /Code/i.test(tf.itemLayer.name)) {
                    techFound = true;

                    // Ignore frames that have text variables
                    if (tf.textVariableInstances.length > 0) continue;

                    // Clean content for comparison
                    var content = String(tf.contents)
                        .replace(/[\s\u00A0\u200B-\u200D\uFEFF]/g, "")
                        .replace(/[^\x20-\x7E]/g, "")
                        .toLowerCase();
                    var cleanFile = String(fileName)
                        .replace(/[\s\u00A0\u200B-\u200D\uFEFF]/g, "")
                        .replace(/[^\x20-\x7E]/g, "")
                        .toLowerCase();

                    if (content.indexOf(cleanFile) === -1) {
                        techMismatch = true;
                        break;
                    }
                }
            }

            if (!techFound) {
                alert("⚠ No text found on the Code layer.");
            } else if (techMismatch) {
                alert("⚠ Code layer text does NOT match the filename: " + fileName);
            }

            // Silent if all is okay

        } catch (e) {
            alert("Error in textVariableCheck: " + e);
        }
    }
})();