async function runAllTestCases() {
        if (isRunning) return;
        isRunning = true;

        const outputBox = document.getElementById('output-box');
        outputBox.textContent = '⏳ Running test cases...';

        const code = editor.getValue();

        try {
            const response = await fetch("{{ route('student.course.verify.testcases') }}", {
                method: "POST",
                headers: {
                    "Content-Type": "application/json",
                    "X-CSRF-TOKEN": csrfToken
                },
                body: JSON.stringify({
                    code: code,
                    language: currentLanguage,
                    question_id: "{{ $id }}"
                })
            });

            const result = await response.json();

            if (result.success) {
                for (let i = 1; i <= totalExpectedTests; i++) {
                    const btn = testButtons[i];
                    if (btn) {
                        btn.classList.remove('bg-green-600', 'bg-red-600', 'bg-gray-400');
                        btn.classList.add('bg-yellow-300', 'text-black');
                    }
                }

                await pollTestResults(result.data.result_url, 'test_run');
            } else {
                outputBox.textContent = '❌ Error: ' + (result.message || 'Test execution failed');
            }

        } catch (error) {
            outputBox.textContent = '❌ Error: ' + error.message;
        } finally {
            isRunning = false;
        }
    }

    function checkAllTestsPassed() {
        let allGreen = true;
        for (let i = 1; i <= 4; i++) {
            const btn = testButtons[i];
            if (btn && !btn.classList.contains('bg-green-600')) {
                allGreen = false;
                break;
            }
        }
        return allGreen;
    }

    function forceCheckSubmitButton() {
        const allGreen = checkAllTestsPassed();
        if (allGreen) {
            allTestsPassed = true;
            enableSubmitButton();
        }
    }

    async function submitFinalSolution() {
        let allGreen = checkAllTestsPassed();
        if (!allGreen && !allTestsPassed) {
            alert("Please pass all test cases first before submitting!");
            return;
        }

        const submitBtn = document.getElementById('submitBtn');
        if (!submitBtn) return;

        submitBtn.disabled = true;
        submitBtn.textContent = "Submitting...";

        const outputBox = document.getElementById('output-box');
        outputBox.textContent = '⏳ Submitting final solution...\n';

        const code = editor.getValue();

        const timerValue = document.getElementById("timer-value").textContent;
        const [minutes, seconds] = timerValue.split(':').map(Number);
        const totalTimeSeconds = (minutes * 60) + seconds;

        try {
            const response = await fetch("{{ route('student.course.compiler.store.report') }}", {
                method: "POST",
                headers: {
                    "Content-Type": "application/json",
                    "X-CSRF-TOKEN": csrfToken
                },
                body: JSON.stringify({
                    code: code,
                    language: currentLanguage,
                    question_id: "{{ $id }}",
                    submission_type: 'final_submission',
                    total_time_seconds: totalTimeSeconds,
                    course_id: "{{ $course_id ?? $coursename ?? '' }}",
                    module_id: "{{ $module_id ?? $module ?? '' }}",
                    topic_id: "{{ $topic_id ?? $topic ?? '' }}"
                })
            });

            const result = await response.json();

            if (result.success) {
                outputBox.textContent = '✅ Final submission queued...\n';
                await pollTestResults(result.data.result_url, 'final_submission');
            } else {
                throw new Error(result.message || 'Submission failed');
            }

        } catch (error) {
            outputBox.textContent = '❌ Error: ' + error.message;
            submitBtn.disabled = false;
            submitBtn.textContent = "✅ Submit Final";
        }
    }

    /* ===== REST OF YOUR CODE UNCHANGED BELOW ===== */
    async function pollTestResults(resultUrl, submissionType) {
        const outputBox = document.getElementById('output-box');
        const submitBtn = document.getElementById('submitBtn');

        let attempts = 0;
        const maxAttempts = 30;
        const pollInterval = 2000;

        outputBox.textContent = '⏳ Running test cases...';

        return new Promise((resolve) => {
            const poll = async () => {
                attempts++;

                if (attempts > maxAttempts) {
                    outputBox.textContent = '❌ Timeout - No response after ' +
                        Math.round((maxAttempts * pollInterval) / 1000) + ' seconds';

                    if (submitBtn) {
                        submitBtn.disabled = false;
                        submitBtn.textContent = "✅ Submit Final";
                    }
                    resolve(false);
                    return;
                }

                try {
                    const url = `${resultUrl}?_t=${Date.now()}`;
                    const response = await fetch(url, {
                        method: 'GET',
                        headers: {
                            'Accept': 'application/json',
                            'Cache-Control': 'no-cache',
                            'Pragma': 'no-cache'
                        },
                        credentials: 'same-origin',
                        cache: 'no-store',
                    });

                    if (response.status === 404) {
                        clearInterval(intervalId);
                        outputBox.textContent = '❌ Result not found (404)';
                        resolve(false);
                        return;
                    }

                    if (response.status === 401) {
                        clearInterval(intervalId);
                        outputBox.textText = '❌ Session expired. Please login again.';
                        resolve(false);
                        return;
                    }

                    if (!response.ok) {
                        throw new Error(`HTTP ${response.status}: ${response.statusText}`);
                    }

                    const contentType = response.headers.get('content-type') || '';
                    if (!contentType.includes('application/json')) {
                        throw new Error(`Expected JSON but got: ${contentType}`);
                    }

                    const data = await response.json();
                    const status = String(data.status || '').toLowerCase();

                    if (status === 'completed' || status === 'done') {
                        clearInterval(intervalId);
                        outputBox.textContent = '✅ Test results received!\n';

                        const testsAllPassed = displayTestResults({ results: data.results || [] }, submissionType);

                        if (submissionType === 'final_submission' && testsAllPassed && data.report_stored) {
                            // ✅ Keep ONLY: "Congratulations! Question Submitted" (already set by displayTestResults)
                            setTimeout(() => autoExitCompiler(), 2000);
                        }

                        resolve(true);
                        return;
                    }

                    if (status === 'error' || data.error) {
                        clearInterval(intervalId);
                        outputBox.textContent = `❌ Error: ${data.error || 'Unknown error'}`;
                        if (submitBtn) {
                            submitBtn.disabled = false;
                            submitBtn.textContent = "✅ Submit Final";
                        }
                        resolve(false);
                        return;
                    }

                    outputBox.textContent = `⏳ Running test cases... (${attempts}/${maxAttempts})`;

                } catch (err) {
                    outputBox.textContent = `⏳ Running test cases... (${attempts}/${maxAttempts})\nError: ${err.message}`;

                    if ((attempts >= 5 && err.message.includes('NetworkError')) ||
                        err.message.includes('Failed to fetch')) {
                        clearInterval(intervalId);
                        outputBox.textContent = '❌ Network error. Please check your connection.';
                        resolve(false);
                    }
                }
            };

            poll();
            const intervalId = setInterval(poll, pollInterval);
        });
    }

    function displayTestResults(results, submissionType) {
        const outputBox = document.getElementById('output-box');

        if (!results || !results.results || !Array.isArray(results.results)) {
            outputBox.textContent = '❌ Error: Invalid test results';
            return false;
        }

        const testResults = results.results;

        // helper: 2nd / 3rd / 4th
        function ordinalSuffix(n) {
            if (n % 100 >= 11 && n % 100 <= 13) return 'th';
            switch (n % 10) {
                case 1: return 'st';
                case 2: return 'nd';
                case 3: return 'rd';
                default: return 'th';
            }
        }

        function failMessage(n) {
            if (n === 1) return 'Test case 1 failed';
            return `${n}${ordinalSuffix(n)} test case failed`;
        }

        let validTestCount = 0;
        let firstFailed = null; // { num, error? }

        for (let i = 0; i < testResults.length; i++) {
            const r = testResults[i];
            if (r.skipped || !r.is_valid) continue;

            validTestCount++;

            const testNum = Number(r.test_num || validTestCount);

            if (r.passed) {
                const btn = testButtons[testNum];
                if (btn) {
                    btn.classList.remove('bg-yellow-300', 'text-black', 'bg-red-600', 'bg-gray-400');
                    btn.classList.add('bg-green-600', 'text-white');
                }
                continue;
            }

            firstFailed = { num: testNum, error: r.error || '' };

            const btn = testButtons[testNum];
            if (btn) {
                btn.classList.remove('bg-yellow-300', 'text-black', 'bg-green-600', 'bg-gray-400');
                btn.classList.add('bg-red-600', 'text-white');
            }
            break;
        }

        if (validTestCount === 0) {
            allTestsPassed = false;
            disableSubmitButton();
            outputBox.textContent = '⚠️ No valid test cases to execute';
            return false;
        }

        if (firstFailed) {
            allTestsPassed = false;
            disableSubmitButton();

            let msg = failMessage(firstFailed.num);
            if (firstFailed.error) msg += `\n${firstFailed.error}`;
            outputBox.textContent = msg;

            return false;
        }

        allTestsPassed = true;

        if (submissionType === 'final_submission') {
            outputBox.textContent = 'Congratulations! Question Submitted';
            return true;
        }

        if (IS_COMPLETED) {
            outputBox.textContent = 'Congratulation: Problem solved';
            return true;
        }

        outputBox.textContent = 'Congratulation: Problem solved. You can now submit.';
        enableSubmitButton();
        return true;
    }

    function enableSubmitButton() {
        const submitBtn = document.getElementById('submitBtn');
        if (!submitBtn) return;
        submitBtn.disabled = false;
        submitBtn.classList.remove("opacity-50", "cursor-not-allowed");
        submitBtn.textContent = "✅ Submit Final";
        allTestsPassed = true;

        for (let i = 1; i <= 4; i++) {
            const btn = testButtons[i];
            if (btn) {
                btn.classList.remove('bg-yellow-300', 'text-black', 'bg-red-600', 'bg-gray-400');
                btn.classList.add('bg-green-600', 'text-white');
            }
        }
    }