using WorkCameraExport.Models;
using WorkCameraExport.Services;

namespace WorkCameraExport.Forms
{
    /// <summary>
    /// 主窗体 - 数据导出功能
    /// </summary>
    public partial class MainForm : Form
    {
        private readonly ApiService _apiService;
        private readonly AppSettings _settings;
        private CancellationTokenSource? _exportCts;
        private bool _isExporting;

        // 预览数据
        private int _totalRecords;
        private int _totalImages;

        public MainForm(ApiService apiService)
        {
            InitializeComponent();
            _apiService = apiService;
            _settings = AppSettings.Load();
            InitializeDefaults();
        }

        /// <summary>
        /// 初始化默认值
        /// </summary>
        private void InitializeDefaults()
        {
            // 设置默认日期范围（最近30天）
            dtpEndDate.Value = DateTime.Today;
            dtpStartDate.Value = DateTime.Today.AddDays(-30);

            // 设置默认导出路径
            if (!string.IsNullOrEmpty(_settings.DefaultExportPath) && 
                Directory.Exists(_settings.DefaultExportPath))
            {
                txtExportPath.Text = _settings.DefaultExportPath;
            }
            else
            {
                txtExportPath.Text = PathService.ExportDirectory;
            }

            UpdateExportButtonState();
        }

        /// <summary>
        /// 预览按钮点击事件
        /// </summary>
        private async void btnPreview_Click(object sender, EventArgs e)
        {
            await DoPreviewAsync();
        }

        /// <summary>
        /// 执行预览查询
        /// </summary>
        private async Task DoPreviewAsync()
        {
            SetQueryControlsEnabled(false);
            lblStatus.Text = "正在查询...";
            lblStatus.ForeColor = Color.Blue;
            dgvPreview.Rows.Clear();
            _totalRecords = 0;
            _totalImages = 0;

            try
            {
                var query = BuildQuery();
                query.PageNum = 1;
                query.PageSize = 50; // 预览最多显示50条

                var (success, message, data) = await _apiService.GetExportListAsync(query);

                if (success && data != null)
                {
                    _totalRecords = data.TotalNum;
                    
                    // 计算图片总数（需要遍历所有记录）
                    _totalImages = await CalculateTotalImagesAsync(query, data.TotalNum);

                    // 显示预览数据
                    foreach (var record in data.Result)
                    {
                        dgvPreview.Rows.Add(
                            record.Id,
                            record.RecordTime?.ToString("yyyy-MM-dd HH:mm") ?? "",
                            record.DeptName,
                            TruncateContent(record.Content, 30),
                            record.Images.Count
                        );
                    }

                    // 更新统计信息
                    lblTotalRecords.Text = $"共 {_totalRecords} 条记录";
                    lblTotalImages.Text = $"约 {_totalImages} 张图片";
                    lblStatus.Text = $"查询完成，共 {_totalRecords} 条记录";
                    lblStatus.ForeColor = Color.Green;
                }
                else
                {
                    ShowError(message);
                }
            }
            catch (Exception ex)
            {
                ShowError($"查询异常: {ex.Message}");
            }
            finally
            {
                SetQueryControlsEnabled(true);
                UpdateExportButtonState();
            }
        }

        /// <summary>
        /// 计算图片总数
        /// </summary>
        private async Task<int> CalculateTotalImagesAsync(WorkRecordExportQuery query, int totalRecords)
        {
            if (totalRecords <= 50)
            {
                // 如果记录数不多，直接从预览数据计算
                var (success, _, data) = await _apiService.GetExportListAsync(query);
                if (success && data != null)
                {
                    return data.Result.Sum(r => r.Images.Count);
                }
            }
            
            // 估算：假设平均每条记录2张图片
            return totalRecords * 2;
        }

        /// <summary>
        /// 构建查询参数
        /// </summary>
        private WorkRecordExportQuery BuildQuery()
        {
            return new WorkRecordExportQuery
            {
                StartDate = dtpStartDate.Value.Date,
                EndDate = dtpEndDate.Value.Date.AddDays(1).AddSeconds(-1),
                DeptName = string.IsNullOrWhiteSpace(txtDeptName.Text) ? null : txtDeptName.Text.Trim(),
                WorkerName = string.IsNullOrWhiteSpace(txtWorkerName.Text) ? null : txtWorkerName.Text.Trim(),
                Content = string.IsNullOrWhiteSpace(txtContent.Text) ? null : txtContent.Text.Trim()
            };
        }

        /// <summary>
        /// 浏览导出路径
        /// </summary>
        private void btnBrowse_Click(object sender, EventArgs e)
        {
            using var dialog = new FolderBrowserDialog
            {
                Description = "选择导出目录",
                UseDescriptionForTitle = true,
                SelectedPath = txtExportPath.Text
            };

            if (dialog.ShowDialog() == DialogResult.OK)
            {
                txtExportPath.Text = dialog.SelectedPath;
                _settings.DefaultExportPath = dialog.SelectedPath;
                _settings.Save();
            }
        }

        /// <summary>
        /// 导出按钮点击事件
        /// </summary>
        private async void btnExport_Click(object sender, EventArgs e)
        {
            if (_isExporting)
            {
                // 取消导出
                _exportCts?.Cancel();
                return;
            }

            if (_totalRecords == 0)
            {
                MessageBox.Show("请先预览数据", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
                return;
            }

            if (string.IsNullOrWhiteSpace(txtExportPath.Text))
            {
                MessageBox.Show("请选择导出目录", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
                return;
            }

            if (!Directory.Exists(txtExportPath.Text))
            {
                MessageBox.Show("导出目录不存在", "提示", MessageBoxButtons.OK, MessageBoxIcon.Warning);
                return;
            }

            await DoExportAsync();
        }

        /// <summary>
        /// 执行导出
        /// </summary>
        private async Task DoExportAsync()
        {
            _isExporting = true;
            _exportCts = new CancellationTokenSource();
            SetExportingState(true);

            var exportPath = Path.Combine(
                txtExportPath.Text,
                $"工作记录导出_{DateTime.Now:yyyyMMdd_HHmmss}.xlsx");

            try
            {
                var query = BuildQuery();
                var excelService = new ExcelService();
                var allRecords = new List<WorkRecordExportDto>();
                var downloadedImages = new Dictionary<string, byte[]>();

                // 阶段1：获取所有数据
                lblStatus.Text = "正在获取数据...";
                progressBar.Value = 0;

                int pageNum = 1;
                int totalPages = (int)Math.Ceiling(_totalRecords / 50.0);

                while (true)
                {
                    if (_exportCts.Token.IsCancellationRequested)
                    {
                        lblStatus.Text = "导出已取消";
                        lblStatus.ForeColor = Color.Orange;
                        return;
                    }

                    query.PageNum = pageNum;
                    query.PageSize = 50;

                    var (success, message, data) = await _apiService.GetExportListAsync(query);

                    if (!success || data == null)
                    {
                        throw new Exception($"获取数据失败: {message}");
                    }

                    allRecords.AddRange(data.Result);

                    // 更新进度
                    int progress = (int)((pageNum * 100.0) / totalPages * 0.3); // 数据获取占30%
                    progressBar.Value = Math.Min(progress, 30);
                    lblProgress.Text = $"获取数据: {pageNum}/{totalPages} 页";

                    if (data.Result.Count < 50 || pageNum >= data.TotalPage)
                        break;

                    pageNum++;
                }

                // 阶段2：下载图片
                lblStatus.Text = "正在下载图片...";
                var allImageUrls = allRecords.SelectMany(r => r.Images).Distinct().ToList();
                int downloadedCount = 0;
                int totalImages = allImageUrls.Count;

                // 使用信号量限制并发数为5
                using var semaphore = new SemaphoreSlim(5);
                var downloadTasks = allImageUrls.Select(async url =>
                {
                    await semaphore.WaitAsync(_exportCts.Token);
                    try
                    {
                        if (_exportCts.Token.IsCancellationRequested)
                            return;

                        var (success, imageData, _) = await _apiService.DownloadImageAsync(url, _exportCts.Token);
                        if (success && imageData != null)
                        {
                            lock (downloadedImages)
                            {
                                downloadedImages[url] = imageData;
                            }
                        }

                        Interlocked.Increment(ref downloadedCount);

                        // 更新进度（在UI线程）
                        this.Invoke(() =>
                        {
                            int progress = 30 + (int)((downloadedCount * 100.0) / totalImages * 0.5); // 图片下载占50%
                            progressBar.Value = Math.Min(progress, 80);
                            lblProgress.Text = $"下载图片: {downloadedCount}/{totalImages}";
                        });
                    }
                    finally
                    {
                        semaphore.Release();
                    }
                });

                await Task.WhenAll(downloadTasks);

                if (_exportCts.Token.IsCancellationRequested)
                {
                    lblStatus.Text = "导出已取消";
                    lblStatus.ForeColor = Color.Orange;
                    return;
                }

                // 阶段3：生成Excel
                lblStatus.Text = "正在生成Excel...";
                progressBar.Value = 80;
                lblProgress.Text = "生成Excel文件...";

                await Task.Run(() =>
                {
                    excelService.GenerateExcel(exportPath, allRecords, downloadedImages, 
                        (current, total) =>
                        {
                            this.Invoke(() =>
                            {
                                int progress = 80 + (int)((current * 100.0) / total * 0.2); // Excel生成占20%
                                progressBar.Value = Math.Min(progress, 100);
                                lblProgress.Text = $"生成Excel: {current}/{total}";
                            });
                        });
                }, _exportCts.Token);

                // 完成
                progressBar.Value = 100;
                lblProgress.Text = "导出完成";
                lblStatus.Text = $"导出完成: {exportPath}";
                lblStatus.ForeColor = Color.Green;

                // 打开文件所在目录
                if (MessageBox.Show("导出完成！是否打开文件所在目录？", "提示", 
                    MessageBoxButtons.YesNo, MessageBoxIcon.Question) == DialogResult.Yes)
                {
                    System.Diagnostics.Process.Start("explorer.exe", $"/select,\"{exportPath}\"");
                }
            }
            catch (OperationCanceledException)
            {
                lblStatus.Text = "导出已取消";
                lblStatus.ForeColor = Color.Orange;
            }
            catch (Exception ex)
            {
                ShowError($"导出失败: {ex.Message}");
            }
            finally
            {
                _isExporting = false;
                _exportCts?.Dispose();
                _exportCts = null;
                SetExportingState(false);
            }
        }

        /// <summary>
        /// 设置查询控件启用状态
        /// </summary>
        private void SetQueryControlsEnabled(bool enabled)
        {
            dtpStartDate.Enabled = enabled;
            dtpEndDate.Enabled = enabled;
            txtDeptName.Enabled = enabled;
            txtWorkerName.Enabled = enabled;
            txtContent.Enabled = enabled;
            btnPreview.Enabled = enabled;
        }

        /// <summary>
        /// 设置导出状态
        /// </summary>
        private void SetExportingState(bool exporting)
        {
            SetQueryControlsEnabled(!exporting);
            txtExportPath.Enabled = !exporting;
            btnBrowse.Enabled = !exporting;
            
            if (exporting)
            {
                btnExport.Text = "取消导出";
                btnExport.BackColor = Color.FromArgb(220, 53, 69);
            }
            else
            {
                btnExport.Text = "导出Excel";
                btnExport.BackColor = Color.FromArgb(40, 167, 69);
                progressBar.Value = 0;
                lblProgress.Text = "";
            }
        }

        /// <summary>
        /// 更新导出按钮状态
        /// </summary>
        private void UpdateExportButtonState()
        {
            btnExport.Enabled = _totalRecords > 0 || _isExporting;
        }

        /// <summary>
        /// 显示错误信息
        /// </summary>
        private void ShowError(string message)
        {
            lblStatus.Text = message;
            lblStatus.ForeColor = Color.Red;
        }

        /// <summary>
        /// 截断内容
        /// </summary>
        private static string TruncateContent(string content, int maxLength)
        {
            if (string.IsNullOrEmpty(content)) return "";
            return content.Length <= maxLength ? content : content[..maxLength] + "...";
        }

        /// <summary>
        /// 窗体关闭事件
        /// </summary>
        private void MainForm_FormClosing(object sender, FormClosingEventArgs e)
        {
            if (_isExporting)
            {
                var result = MessageBox.Show("正在导出中，确定要取消并退出吗？", "确认", 
                    MessageBoxButtons.YesNo, MessageBoxIcon.Question);
                
                if (result == DialogResult.No)
                {
                    e.Cancel = true;
                    return;
                }

                _exportCts?.Cancel();
            }
        }

        /// <summary>
        /// 历史数据迁移按钮点击事件
        /// </summary>
        private void btnMigration_Click(object sender, EventArgs e)
        {
            if (_isExporting)
            {
                MessageBox.Show("正在导出中，请等待导出完成后再进行迁移操作", "提示", 
                    MessageBoxButtons.OK, MessageBoxIcon.Information);
                return;
            }

            using var migrationForm = new MigrationForm(_apiService);
            migrationForm.ShowDialog(this);
        }
    }
}