document.querySelector('.file-input-button').addEventListener('click', function() {
    document.getElementById('file').click();
});

document.getElementById('file').addEventListener('change', function(e) {
    const fileName = e.target.files[0] ? e.target.files[0].name : '未选择文件';
    document.getElementById('file-name').textContent = fileName;
});

document.getElementById('upload-form').addEventListener('submit', async (e) => {
    e.preventDefault();
    handleSubmission();
});

document.getElementById('verify-submit-button').addEventListener('click', async () => {
    await validateCodeAndSubmit();
});

async function handleSubmission() {
    const assignment = document.getElementById('assignment').value;
    const file = document.getElementById('file').files[0];
    const statusDiv = document.getElementById('status');

    if (!assignment || !file) {
        alert('请选择作业，并选择一个文件。');
        return;
    }

    setLoadingState(true);

    try {
        const recordResponse = await fetch('/record-submission', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json'
            },
            body: JSON.stringify({ assignment, filename: file.name })
        });

        if (recordResponse.status === 401) {
            setLoadingState(false);
            document.getElementById('verification-container').style.display = 'block';

            const emailResponse = await fetch('/generate-code', {
                method: 'POST',
                headers: {
                    'Content-Type': 'application/json'
                },
                body: JSON.stringify({ assignment })
            });

            if (emailResponse.ok) {
                alert('作业已提交过，请输入验证码提交');
            } else {
                const errorData = await emailResponse.json();
                throw new Error(`发送验证码失败: ${errorData.error}`);
            }
        } else if (!recordResponse.ok) {
            const errorRecordData = await recordResponse.json();
            throw new Error(`记录提交信息失败: ${errorRecordData.error}`);
        } else {
            const data = await recordResponse.json();
            await uploadFile(data.upload_url, file, statusDiv);
            alert('文件上传并记录成功');
        }
    } catch (error) {
        console.error('错误:', error);
        statusDiv.textContent = `错误: ${error.message}`;
        alert('发生错误: ' + error.message);
    } finally {
        setLoadingState(false);
    }
}

async function validateCodeAndSubmit() {
    const assignment = document.getElementById('assignment').value;
    const file = document.getElementById('file').files[0];
    const code = document.getElementById('verification-code').value;
    const statusDiv = document.getElementById('status');

    setLoadingState(true, true);

    try {
        const validateResponse = await fetch('/validate-code', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json'
            },
            body: JSON.stringify({ assignment, code })
        });

        if (validateResponse.ok) {
            const { upload_url } = await validateResponse.json();
            await uploadFile(upload_url, file, statusDiv);
            alert('文件上传并记录成功');
            document.getElementById('verification-container').style.display = 'none';
        } else {
            const errorData = await validateResponse.json();
            throw new Error(`验证码错误: ${errorData.error}`);
        }
    } catch (error) {
        console.error('错误:', error);
        statusDiv.textContent = `错误: ${error.message}`;
        alert('发生错误: ' + error.message);
    } finally {
        setLoadingState(false, true);
    }
}

async function uploadFile(upload_url, file, statusDiv) {
    const progressContainer = document.getElementById('progress-container');
    const progressBar = document.getElementById('progress-bar');
    const progressPercentage = document.getElementById('progress-percentage');
    const uploadSpeed = document.getElementById('upload-speed');
    const uploadSize = document.getElementById('upload-size');
    const uploadTime = document.getElementById('upload-time');

    statusDiv.textContent = '正在上传文件...';
    const totalSize = file.size;
    let uploadedSize = 0;
    let startTime = Date.now();

    progressContainer.style.display = 'block';

    const updateProgress = (additionalProgress = 0) => {
        uploadedSize += additionalProgress;
        const percentComplete = (uploadedSize / totalSize) * 100;
        const elapsedTime = (Date.now() - startTime) / 1000;
        const speed = uploadedSize / elapsedTime;
        const remainingSize = totalSize - uploadedSize;
        const estimatedRemainingTime = speed > 0 ? remainingSize / speed : 0;

        progressBar.style.width = percentComplete + '%';
        progressPercentage.textContent = percentComplete.toFixed(2) + '%';
        uploadSpeed.textContent = `速度: ${formatSize(speed)}/s`;
        uploadSize.textContent = `${formatSize(uploadedSize)} / ${formatSize(totalSize)}`;
        uploadTime.textContent = `剩余时间: ${formatTime(estimatedRemainingTime)}`;
    };

    const progressInterval = setInterval(() => {
        if (uploadedSize < totalSize) {
            updateProgress(totalSize / 100);
        }
    }, 200);

    const uploadResponse = await fetch(upload_url, {
        method: 'PUT',
        body: file,
        headers: {
            'Content-Type': 'application/octet-stream'
        }
    });

    clearInterval(progressInterval);

    if (!uploadResponse.ok) {
        throw new Error(`上传失败: ${uploadResponse.statusText}`);
    }

    updateProgress(totalSize - uploadedSize);
}

function setLoadingState(isLoading, isVerify = false) {
    const submitButton = document.querySelector('button[type="submit"]');
    const verifyButton = document.getElementById('verify-submit-button');
    const container = isVerify ? verifyButton.parentElement : submitButton.parentElement;

    const loadingIndicator = container.querySelector('.loading-indicator') || document.createElement('div');
    loadingIndicator.className = 'loading-indicator';
    loadingIndicator.innerHTML = '<span>加载中...</span>';
    loadingIndicator.style.display = isLoading ? 'block' : 'none';

    if (!loadingIndicator.parentElement) {
        container.appendChild(loadingIndicator);
    }

    if (isVerify) {
        verifyButton.disabled = isLoading;
    } else {
        submitButton.disabled = isLoading;
    }
}

function formatSize(bytes) {
    if (bytes === 0) return '0 Bytes';
    const k = 1024;
    const sizes = ['Bytes', 'KB', 'MB', 'GB', 'TB'];
    const i = Math.floor(Math.log(bytes) / Math.log(k));
    return parseFloat((bytes / Math.pow(k, i)).toFixed(2)) + ' ' + sizes[i];
}

function formatTime(seconds) {
    if (isNaN(seconds) || !isFinite(seconds)) {
        return '计算中';
    }
    if (seconds < 60) return Math.round(seconds) + ' 秒';
    const minutes = Math.floor(seconds / 60);
    const remainingSeconds = Math.round(seconds % 60);
    return `${minutes} 分 ${remainingSeconds} 秒`;
}

function previewTable(apiUrl, title) {
    fetch(apiUrl)
        .then(response => response.json())
        .then(data => {
            const newWindow = window.open('', '_blank');
            newWindow.document.write('<html><head><title>' + title + '</title><style>');
            newWindow.document.write('table { width: 100%; border-collapse: collapse; margin-top: 10px; }');
            newWindow.document.write('th, td { border: 1px solid #ddd; padding: 8px; text-align: left; word-wrap: break-word; }');
            newWindow.document.write('th { background-color: #f2f2f2; }');
            newWindow.document.write('body { font-family: Arial, sans-serif; padding: 20px; }');
            newWindow.document.write('</style></head><body>');
            newWindow.document.write('<h2>' + title + '</h2>');

            const table = newWindow.document.createElement('table');

            if (data.length > 0) {
                let headers;
                if (title === '预览统计表格') {
                    headers = ['时间', '提交的文件', '姓名', '学号', '作业'];
                } else {
                    headers = ['学号', '姓名', '作业', '提交情况', '提交的文件'];
                }

                const thead = newWindow.document.createElement('thead');
                const tr = newWindow.document.createElement('tr');
                headers.forEach((header, index) => {
                    const th = newWindow.document.createElement('th');
                    th.textContent = header;
                    // 设置列宽
                    if (title === '预览统计表格') {
                        if (index === 0) th.style.width = '20%'; // 时间
                        else if (index === 1) th.style.width = '30%'; // 提交的文件
                        else if (index === 2) th.style.width = '15%'; // 姓名
                        else if (index === 3) th.style.width = '15%'; // 学号
                        else if (index === 4) th.style.width = '20%'; // 作业
                    } else {
                        if (index === 0) th.style.width = '15%'; // 学号
                        else if (index === 1) th.style.width = '15%'; // 姓名
                        else if (index === 2) th.style.width = '20%'; // 作业
                        else if (index === 3) th.style.width = '15%'; // 提交情况
                        else if (index === 4) th.style.width = '35%'; // 提交的文件
                    }
                    tr.appendChild(th);
                });
                thead.appendChild(tr);
                table.appendChild(thead);
            }

            const tbody = newWindow.document.createElement('tbody');
            data.forEach(row => {
                const tr = newWindow.document.createElement('tr');
                if (title === '预览统计表格') {
                    ['时间', '提交的文件', '姓名', '学号', '作业'].forEach(key => {
                        const td = newWindow.document.createElement('td');
                        td.textContent = row[key] || '';
                        tr.appendChild(td);
                    });
                } else {
                    ['学号', '姓名', '作业', '提交情况', '提交的文件'].forEach(key => {
                        const td = newWindow.document.createElement('td');
                        td.textContent = row[key] || '';
                        tr.appendChild(td);
                    });
                }
                tbody.appendChild(tr);
            });

            table.appendChild(tbody);
            newWindow.document.body.appendChild(table);
            newWindow.document.write('</body></html>');
            newWindow.document.close();
        })
        .catch(error => console.error('Error fetching data:', error));
}