using WorkCameraExport.Models;
using WorkCameraExport.Services;

namespace WorkCameraExport.Forms
{
    /// <summary>
    /// 迁移窗体 - 历史数据迁移功能
    /// </summary>
    public partial class MigrationForm : Form
    {
        private readonly ApiService _apiService;
        private readonly CosService _cosService;
        private CancellationTokenSource? _migrationCts;
        private bool _isMigrating;

        // 记录数据
        private List<MigrationRecordDto> _records = new();
        private int _totalRecords;

        public MigrationForm(ApiService apiService)
        {
            InitializeComponent();
            _apiService = apiService;
            _cosService = new CosService();
        }

        /// <summary>
        /// 窗体加载事件
        /// </summary>
        private void MigrationForm_Load(object sender, EventArgs e)
        {
            InitializeDefaults();
        }

        /// <summary>
        /// 初始化默认值
        /// </summary>
        private void InitializeDefaults()
        {
            // 设置默认日期范围（最近90天）
            dtpEndDate.Value = DateTime.Today;
            dtpStartDate.Value = DateTime.Today.AddDays(-90);

            // 设置默认状态为"未迁移"
            cboStatus.SelectedIndex = 1; // 未迁移

            UpdateMigrateButtonState();
        }

        #region 查询功能

        /// <summary>
        /// 查询按钮点击事件
        /// </summary>
        private async void btnQuery_Click(object sender, EventArgs e)
        {
            await DoQueryAsync();
        }

        /// <summary>
        /// 执行查询
        /// </summary>
        private async Task DoQueryAsync()
        {
            SetQueryControlsEnabled(false);
            lblStatusBar.Text = "正在查询...";
            lblStatusBar.ForeColor = Color.Blue;
            dgvRecords.Rows.Clear();
            _records.Clear();
            _totalRecords = 0;

            try
            {
                var query = BuildQuery();
                query.PageNum = 1;
                query.PageSize = 50;

                // 获取所有记录（分页获取）
                var allRecords = new List<MigrationRecordDto>();
                int pageNum = 1;

                while (true)
                {
                    query.PageNum = pageNum;
                    var (success, message, data) = await _apiService.GetMigrationListAsync(query);

                    if (!success || data == null)
                    {
                        ShowError(message);
                        return;
                    }

                    allRecords.AddRange(data.Result);
                    _totalRecords = data.TotalNum;

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

                    pageNum++;

                    // 更新状态
                    lblStatusBar.Text = $"正在查询... 已获取 {allRecords.Count} 条";
                }

                _records = allRecords;

                // 显示数据
                foreach (var record in _records)
                {
                    dgvRecords.Rows.Add(
                        false, // 选择框
                        record.Id,
                        record.RecordTime?.ToString("yyyy-MM-dd HH:mm") ?? "",
                        record.DeptName,
                        TruncateContent(record.Content, 40),
                        record.ImageCount,
                        GetStatusText(record.MigrationStatus)
                    );
                }

                // 更新统计信息
                lblTotalRecords.Text = $"共 {_totalRecords} 条记录";
                UpdateSelectedCount();
                lblStatusBar.Text = $"查询完成，共 {_totalRecords} 条记录";
                lblStatusBar.ForeColor = Color.Green;
            }
            catch (Exception ex)
            {
                ShowError($"查询异常: {ex.Message}");
            }
            finally
            {
                SetQueryControlsEnabled(true);
                UpdateMigrateButtonState();
            }
        }

        /// <summary>
        /// 构建查询参数
        /// </summary>
        private MigrationQuery BuildQuery()
        {
            int? status = cboStatus.SelectedIndex switch
            {
                1 => 0, // 未迁移
                2 => 1, // 已迁移
                3 => 2, // 迁移失败
                _ => null // 全部
            };

            return new MigrationQuery
            {
                StartDate = dtpStartDate.Value.Date,
                EndDate = dtpEndDate.Value.Date.AddDays(1).AddSeconds(-1),
                Status = status
            };
        }

        /// <summary>
        /// 获取状态文本
        /// </summary>
        private static string GetStatusText(int status)
        {
            return status switch
            {
                0 => "未迁移",
                1 => "已迁移",
                2 => "迁移失败",
                _ => "未知"
            };
        }

        #endregion

        #region 选择功能

        /// <summary>
        /// 全选/取消复选框变更事件
        /// </summary>
        private void chkSelectAll_CheckedChanged(object sender, EventArgs e)
        {
            foreach (DataGridViewRow row in dgvRecords.Rows)
            {
                row.Cells[0].Value = chkSelectAll.Checked;
            }
            UpdateSelectedCount();
            UpdateMigrateButtonState();
        }

        /// <summary>
        /// 数据网格单元格点击事件
        /// </summary>
        private void dgvRecords_CellContentClick(object sender, DataGridViewCellEventArgs e)
        {
            if (e.ColumnIndex == 0 && e.RowIndex >= 0)
            {
                // 延迟更新，等待复选框状态变更
                BeginInvoke(new Action(() =>
                {
                    UpdateSelectedCount();
                    UpdateMigrateButtonState();
                }));
            }
        }

        /// <summary>
        /// 更新已选数量
        /// </summary>
        private void UpdateSelectedCount()
        {
            int selectedCount = GetSelectedRecordIds().Count;
            lblSelectedRecords.Text = $"已选 {selectedCount} 条";
        }

        /// <summary>
        /// 获取选中的记录ID列表
        /// </summary>
        private List<int> GetSelectedRecordIds()
        {
            var selectedIds = new List<int>();
            foreach (DataGridViewRow row in dgvRecords.Rows)
            {
                if (row.Cells[0].Value is true)
                {
                    if (int.TryParse(row.Cells[1].Value?.ToString(), out int id))
                    {
                        selectedIds.Add(id);
                    }
                }
            }
            return selectedIds;
        }

        /// <summary>
        /// 获取选中的记录
        /// </summary>
        private List<MigrationRecordDto> GetSelectedRecords()
        {
            var selectedIds = GetSelectedRecordIds();
            return _records.Where(r => selectedIds.Contains(r.Id)).ToList();
        }

        #endregion

        #region 迁移功能

        /// <summary>
        /// 迁移按钮点击事件
        /// </summary>
        private async void btnMigrate_Click(object sender, EventArgs e)
        {
            if (_isMigrating)
            {
                // 取消迁移
                _migrationCts?.Cancel();
                return;
            }

            var selectedRecords = GetSelectedRecords();
            if (selectedRecords.Count == 0)
            {
                MessageBox.Show("请先选择要迁移的记录", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
                return;
            }

            var result = MessageBox.Show(
                $"确定要迁移选中的 {selectedRecords.Count} 条记录吗？\n\n迁移过程中请勿关闭程序。",
                "确认迁移",
                MessageBoxButtons.YesNo,
                MessageBoxIcon.Question);

            if (result != DialogResult.Yes)
                return;

            await DoMigrationAsync(selectedRecords);
        }

        /// <summary>
        /// 执行迁移
        /// </summary>
        private async Task DoMigrationAsync(List<MigrationRecordDto> records)
        {
            _isMigrating = true;
            _migrationCts = new CancellationTokenSource();
            SetMigratingState(true);

            int successCount = 0;
            int failCount = 0;
            int totalRecords = records.Count;
            int processedRecords = 0;

            try
            {
                // 获取 COS 临时密钥
                lblCurrentRecord.Text = "正在获取 COS 临时密钥...";
                var (credSuccess, credMessage, credentials) = await _apiService.GetTempCredentialsAsync();

                if (!credSuccess || credentials == null)
                {
                    ShowError($"获取 COS 临时密钥失败: {credMessage}");
                    return;
                }

                // 初始化 COS 服务
                _cosService.Initialize(credentials);

                // 逐条迁移记录
                foreach (var record in records)
                {
                    if (_migrationCts.Token.IsCancellationRequested)
                    {
                        lblStatusBar.Text = "迁移已取消";
                        lblStatusBar.ForeColor = Color.Orange;
                        break;
                    }

                    processedRecords++;
                    lblCurrentRecord.Text = $"正在迁移记录 {record.Id} ({processedRecords}/{totalRecords})...";

                    try
                    {
                        var migrationResult = await MigrateRecordAsync(record, _migrationCts.Token);
                        
                        if (migrationResult)
                        {
                            successCount++;
                            UpdateRowStatus(record.Id, "已迁移", Color.Green);
                        }
                        else
                        {
                            failCount++;
                            UpdateRowStatus(record.Id, "迁移失败", Color.Red);
                        }
                    }
                    catch (OperationCanceledException)
                    {
                        break;
                    }
                    catch (Exception ex)
                    {
                        failCount++;
                        UpdateRowStatus(record.Id, "迁移失败", Color.Red);
                        System.Diagnostics.Debug.WriteLine($"迁移记录 {record.Id} 失败: {ex.Message}");
                    }

                    // 更新进度
                    int progress = (int)((processedRecords * 100.0) / totalRecords);
                    progressBar.Value = progress;
                    lblProgress.Text = $"{progress}%";
                }

                // 完成
                if (!_migrationCts.Token.IsCancellationRequested)
                {
                    progressBar.Value = 100;
                    lblProgress.Text = "100%";
                    lblCurrentRecord.Text = $"迁移完成！成功: {successCount}, 失败: {failCount}";
                    lblStatusBar.Text = $"迁移完成，成功 {successCount} 条，失败 {failCount} 条";
                    lblStatusBar.ForeColor = failCount > 0 ? Color.Orange : Color.Green;

                    MessageBox.Show(
                        $"迁移完成！\n\n成功: {successCount} 条\n失败: {failCount} 条",
                        "迁移结果",
                        MessageBoxButtons.OK,
                        failCount > 0 ? MessageBoxIcon.Warning : MessageBoxIcon.Information);
                }
            }
            catch (Exception ex)
            {
                ShowError($"迁移异常: {ex.Message}");
            }
            finally
            {
                _isMigrating = false;
                _migrationCts?.Dispose();
                _migrationCts = null;
                SetMigratingState(false);
            }
        }

        /// <summary>
        /// 迁移单条记录
        /// </summary>
        private async Task<bool> MigrateRecordAsync(MigrationRecordDto record, CancellationToken cancellationToken)
        {
            var urlPairs = new List<MigrationUrlPair>();

            // 获取需要迁移的图片（未迁移的）
            var imagesToMigrate = record.Images.Where(img => !img.IsMigrated).ToList();

            if (imagesToMigrate.Count == 0)
            {
                // 没有需要迁移的图片，直接返回成功
                return true;
            }

            int imageIndex = 0;
            int totalImages = imagesToMigrate.Count;

            foreach (var image in imagesToMigrate)
            {
                if (cancellationToken.IsCancellationRequested)
                    throw new OperationCanceledException();

                imageIndex++;
                lblCurrentRecord.Text = $"正在迁移记录 {record.Id} - 图片 {imageIndex}/{totalImages}...";

                try
                {
                    // 1. 下载原图片
                    var (downloadSuccess, imageData, downloadMessage) = 
                        await _apiService.DownloadImageAsync(image.Url, cancellationToken);

                    if (!downloadSuccess || imageData == null)
                    {
                        System.Diagnostics.Debug.WriteLine($"下载图片失败: {image.Url} - {downloadMessage}");
                        continue; // 跳过失败的图片，继续处理其他图片
                    }

                    // 2. 生成 COS 路径
                    var recordTime = record.RecordTime ?? DateTime.Now;
                    var fileName = CosService.GenerateFileName(".jpg");
                    var cosKey = CosService.GenerateCosKey(recordTime, "当日照片", "", fileName);

                    // 3. 上传到 COS
                    var (uploadSuccess, uploadMessage, cosUrl) = 
                        await _cosService.UploadBytesAsync(imageData, cosKey, cancellationToken: cancellationToken);

                    if (!uploadSuccess || string.IsNullOrEmpty(cosUrl))
                    {
                        System.Diagnostics.Debug.WriteLine($"上传图片失败: {uploadMessage}");
                        continue; // 跳过失败的图片，继续处理其他图片
                    }

                    // 4. 记录 URL 映射
                    urlPairs.Add(new MigrationUrlPair
                    {
                        OldUrl = image.Url,
                        NewUrl = cosUrl
                    });
                }
                catch (OperationCanceledException)
                {
                    throw;
                }
                catch (Exception ex)
                {
                    System.Diagnostics.Debug.WriteLine($"处理图片异常: {image.Url} - {ex.Message}");
                    continue; // 跳过失败的图片，继续处理其他图片
                }
            }

            // 5. 调用 API 更新 URL
            if (urlPairs.Count > 0)
            {
                var updateRequest = new MigrationUpdateRequest
                {
                    RecordId = record.Id,
                    ImageUrls = urlPairs
                };

                var (updateSuccess, updateMessage) = await _apiService.UpdateMigrationUrlsAsync(updateRequest);

                if (!updateSuccess)
                {
                    System.Diagnostics.Debug.WriteLine($"更新 URL 失败: {updateMessage}");
                    return false;
                }
            }

            // 如果所有图片都成功迁移，返回成功
            return urlPairs.Count == imagesToMigrate.Count;
        }

        /// <summary>
        /// 更新行状态
        /// </summary>
        private void UpdateRowStatus(int recordId, string status, Color color)
        {
            foreach (DataGridViewRow row in dgvRecords.Rows)
            {
                if (row.Cells[1].Value?.ToString() == recordId.ToString())
                {
                    row.Cells[6].Value = status;
                    row.Cells[6].Style.ForeColor = color;
                    break;
                }
            }
        }

        #endregion

        #region UI 辅助方法

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

        /// <summary>
        /// 设置迁移状态
        /// </summary>
        private void SetMigratingState(bool migrating)
        {
            SetQueryControlsEnabled(!migrating);
            dgvRecords.Enabled = !migrating;
            chkSelectAll.Enabled = !migrating;

            if (migrating)
            {
                btnMigrate.Text = "取消迁移";
                btnMigrate.BackColor = Color.FromArgb(220, 53, 69);
            }
            else
            {
                btnMigrate.Text = "开始迁移";
                btnMigrate.BackColor = Color.FromArgb(40, 167, 69);
                progressBar.Value = 0;
                lblProgress.Text = "";
            }
        }

        /// <summary>
        /// 更新迁移按钮状态
        /// </summary>
        private void UpdateMigrateButtonState()
        {
            btnMigrate.Enabled = GetSelectedRecordIds().Count > 0 || _isMigrating;
        }

        /// <summary>
        /// 显示错误信息
        /// </summary>
        private void ShowError(string message)
        {
            lblStatusBar.Text = message;
            lblStatusBar.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 MigrationForm_FormClosing(object sender, FormClosingEventArgs e)
        {
            if (_isMigrating)
            {
                var result = MessageBox.Show(
                    "正在迁移中，确定要取消并退出吗？",
                    "确认",
                    MessageBoxButtons.YesNo,
                    MessageBoxIcon.Question);

                if (result == DialogResult.No)
                {
                    e.Cancel = true;
                    return;
                }

                _migrationCts?.Cancel();
            }

            // 释放 COS 服务
            _cosService.Dispose();
        }

        #endregion
    }
}