// ============================================================================
// LabPicUrlPreview.cs  （C# 7.3 / DevExpress 15.2 兼容）
// - 公用方法封装在一个类里：InitPicColumn / Attach / AttachPreview
// - 线程安全缓存：缩略图 & 原图 分离缓存；并发限流 + LRU 清理
// - 只在同步阶段写 e.Value；异步完成后刷新单元格或更新预览窗体
// ============================================================================
using System;
using System.Collections.Generic;
using System.Data;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Net;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;

using DevExpress.Data;
using DevExpress.XtraEditors.Controls;
using DevExpress.XtraEditors.Repository;
using DevExpress.XtraGrid;
using DevExpress.XtraGrid.Columns;
using DevExpress.XtraGrid.Views.Base;
using DevExpress.XtraGrid.Views.Grid;
using DevExpress.XtraGrid.Views.BandedGrid;
using DevExpress.XtraGrid.Views.Grid.ViewInfo;
using DevExpress.XtraGrid.Views.BandedGrid.ViewInfo;
using Lskj.Control.Model;
using Lskj.Control;
using Lskj.Business;

public static class LabPicUrlPreview
{
    // ====== 对外：初始化图片列（创建 RepositoryItemPictureEdit、设为 Unbound） ======
    public static void InitPicColumn(GridControl gridControl, GridColumn gridColumn, GridColumnModel model)
    {
        if (gridControl == null || gridColumn == null || model == null) return;

        gridColumn.AppearanceCell.Options.UseTextOptions = true;
        gridColumn.AppearanceCell.TextOptions.HAlignment = DevExpress.Utils.HorzAlignment.Center;
        gridColumn.OptionsColumn.AllowEdit = false;

        // 唯一列名（保持你原逻辑）
        gridColumn.FieldName = string.Format("{0}{1}", model.FieldName, Guid.NewGuid());
        //gridColumn.FieldName = model.FieldName;
        gridColumn.Tag = model; // 事件里取模型

        RepositoryItemPictureEdit pictureEdit = new RepositoryItemPictureEdit();
        pictureEdit.ShowMenu = false;
        pictureEdit.NullText = " ";
        pictureEdit.SizeMode = PictureSizeMode.Zoom;

        gridControl.RepositoryItems.Add(pictureEdit);
        gridColumn.UnboundType = UnboundColumnType.Object;
        gridColumn.ColumnEdit = pictureEdit;
    }

    // ====== 对外：绑定“取缩略图”的事件（只需调用一次） ======
    public static void Attach(ColumnView view)
    {
        if (view == null) return;
        view.CustomUnboundColumnData -= OnCustomUnboundColumnData;
        view.CustomUnboundColumnData += OnCustomUnboundColumnData;
    }

    // ====== 对外：绑定“双击大图预览”的事件（只需调用一次） ======
    public static void AttachPreview(ColumnView view)
    {
        if (view == null) return;
        view.DoubleClick -= OnViewDoubleClick;
        view.DoubleClick += OnViewDoubleClick;
    }

    // ===================== 缩略图事件实现 =====================
    private static void OnCustomUnboundColumnData(object sender, CustomColumnDataEventArgs e)
    {
        ColumnView view = sender as ColumnView;
        if (view == null) return;

        GridColumnModel m = e.Column.Tag as GridColumnModel;
        if (m == null || m.FieldType != ControlType.LabPicUrl || !e.IsGetData) return;

        // 1) 用 ListSourceRowIndex → RowHandle（兼容 DevExpress 15.2）
        int listIndex = e.ListSourceRowIndex;
        int rowHandle = view.GetRowHandle(listIndex);

        // 2) 读取原始 URL（优先 ListSource；兜底 e.Row）
        string raw = null;
        try
        {
            object val = view.GetListSourceRowCellValue(listIndex, m.FieldName);
            raw = val == null ? null : Convert.ToString(val);
        }
        catch
        {
            DataRowView drv = e.Row as DataRowView;
            if (drv != null && drv.Row != null && drv.Row.Table != null && drv.Row.Table.Columns.Contains(m.FieldName))
                raw = Convert.ToString(drv.Row[m.FieldName]);
        }
        if (string.IsNullOrWhiteSpace(raw)) return;

        // 3) 拼接完整 URL（相对路径 -> OA 根地址）
        string url = ResolveFullUrl(raw);

        // 4) 目标高（属性或方法都兼容；<=18 则用 30）
        int targetHeight = NormalizeHeight(m);

        // 5) 缓存命中：当次赋值（只在同步阶段写 e.Value）
        Image img;
        if (ImageCache.TryGetThumb(url, targetHeight, out img))
        {
            e.Value = img;
            return;
        }

        // 6) 未命中：安排异步下载；完成后刷新该单元格（不要在异步线程里改 e.Value）
        System.Windows.Forms.Control invoker = view.GridControl; // UI 回调对象
        ImageCache.GetThumbAsync(url, targetHeight, invoker, delegate ()
        {
            RefreshCellCompat(view, rowHandle, e.Column);
        });
    }

    // ===================== 双击预览（原图） =====================
    private static void OnViewDoubleClick(object sender, EventArgs e)
    {
        ColumnView view = sender as ColumnView;
        if (view == null || view.GridControl == null) return;

        // 命中测试（GridView / BandedGridView 兼容）
        GridColumn hitColumn = null;
        int rowHandle = -1;

        Point pt = view.GridControl.PointToClient(Control.MousePosition);

        GridView gv = view as GridView;
        if (gv != null)
        {
            GridHitInfo hi = gv.CalcHitInfo(pt);
            if (hi == null || !hi.InRowCell || hi.Column == null) return;
            hitColumn = hi.Column;
            rowHandle = hi.RowHandle;
        }
        else
        {
            BandedGridView bgv = view as BandedGridView;
            if (bgv == null) return;
            BandedGridHitInfo hi2 = bgv.CalcHitInfo(pt);
            if (hi2 == null || !hi2.InRowCell || hi2.Column == null) return;
            hitColumn = hi2.Column;
            rowHandle = hi2.RowHandle;
        }

        // 只处理 LabPicUrl 列
        GridColumnModel m = hitColumn.Tag as GridColumnModel;
        if (m == null || m.FieldType != ControlType.LabPicUrl) return;

        // 取当前行的 URL（优先 RowHandle 取值）
        string raw = null;
        try
        {
            object val = view.GetRowCellValue(rowHandle, m.FieldName);
            raw = val == null ? null : Convert.ToString(val);
        }
        catch
        {
            // 兜底：通过 ListSourceRowIndex
            int listIndex = view.GetDataSourceRowIndex(rowHandle);
            try
            {
                object val2 = view.GetListSourceRowCellValue(listIndex, m.FieldName);// "GM_leb_TuShi_ZS"
                raw = val2 == null ? null : Convert.ToString(val2);
            }
            catch { }
        }
        if (string.IsNullOrWhiteSpace(raw)) return;

        string url = ResolveFullUrl(raw);

        // —— 打开你的预览窗体（先以缩略图占位） ——
        Image thumb = null;
        ImageCache.TryGetThumb(url, NormalizeHeight(m), out thumb);

        FrmPicture frm = new FrmPicture();
        try
        {
            // 这些属性基于你原有窗体接口
            frm.PicUrlColumns = view.Columns
                .Where(c => c.Tag is GridColumnModel cm && cm.FieldType == ControlType.LabPicUrl)
                .ToList();
            frm.FocusedRow = (view as GridView) != null ? (view as GridView).GetDataRow(rowHandle) : null;
            frm.FocusedColumn = hitColumn;
            frm.Text = "预览";
            frm.Picture = thumb;  // 先用缩略图（可能为 null）
            frm.WindowState = FormWindowState.Maximized;
            frm.StartPosition = FormStartPosition.CenterScreen;

            // 异步拉原图，完成后更新窗体
            ImageCache.GetFullAsync(url, frm, delegate (Image full)
            {
                if (full == null) return;
                try
                {
                    if (!frm.IsDisposed) frm.Picture = full;
                }
                catch { }
            });

            frm.ShowDialog();
        }
        finally
        {
            if (frm != null && !frm.IsDisposed) frm.Dispose();
        }
    }

    // ====== 视图安全刷新：GridView/BandedGridView 定向刷新，其他降级为 RefreshData ======
    private static void RefreshCellCompat(ColumnView view, int rowHandle, GridColumn column)
    {
        try
        {
            GridView gv = view as GridView;
            if (gv != null)
            {
                if (rowHandle >= 0) gv.RefreshRowCell(rowHandle, column);
                else gv.RefreshData();
                return;
            }

            BandedGridView bgv = view as BandedGridView;
            if (bgv != null)
            {
                if (rowHandle >= 0) bgv.RefreshRowCell(rowHandle, column);
                else bgv.RefreshData();
                return;
            }

            view.RefreshData();
        }
        catch
        {
            try { view.RefreshData(); } catch { }
        }
    }

    // ====== 兼容“属性或无参方法”的高度读取（避免 m.LabPicUrlHeight 被当作方法组出错） ======
    private static int NormalizeHeight(object model)
    {
        try
        {
            var t = model.GetType();

            // 属性
            var pi = t.GetProperty("LabPicUrlHeight");
            if (pi != null)
            {
                int v = Convert.ToInt32(pi.GetValue(model, null));
                return v <= 18 ? 30 : v;
            }

            // 无参方法
            var mi = t.GetMethod("LabPicUrlHeight", Type.EmptyTypes);
            if (mi != null)
            {
                int v = Convert.ToInt32(mi.Invoke(model, null));
                return v <= 18 ? 30 : v;
            }
        }
        catch { }
        return 30;
    }

    // ====== 解析完整 URL：相对路径 -> SystemInfo.Instance.OAUrl + 相对 ======
    private static string ResolveFullUrl(string raw)
    {
        if (string.IsNullOrEmpty(raw)) return raw;
        if (raw.StartsWith("http", StringComparison.OrdinalIgnoreCase)) return raw;

        try
        {
            string oa = SystemInfo.Instance.OAUrl;
            if (string.IsNullOrEmpty(oa)) return raw.TrimStart('/');
            if (!oa.EndsWith("/")) oa += "/";
            return oa + raw.TrimStart('/');
        }
        catch
        {
            return raw.TrimStart('/');
        }
    }

    // ====== 图片缓存（缩略图 & 原图）—— WebClient + Dictionary + Semaphore，C# 7.3 兼容 ======
    private static class ImageCache
    {
        // —— 公共接口（缩略图） ——
        public static bool TryGetThumb(string url, int targetHeight, out Image img)
        {
            return ThumbCache.TryGet(url, targetHeight, out img);
        }
        public static void GetThumbAsync(string url, int targetHeight, System.Windows.Forms.Control invoker, Action onReady)
        {
            ThumbCache.GetOrCreateAsync(url, targetHeight, invoker, onReady);
        }

        // —— 公共接口（原图） ——
        public static bool TryGetFull(string url, out Image img)
        {
            return FullCache.TryGet(url, out img);
        }
        public static void GetFullAsync(string url, System.Windows.Forms.Control invoker, Action<Image> onReady)
        {
            FullCache.GetOrCreateAsync(url, invoker, onReady);
        }

        // ===== 缩略图缓存实现 =====
        private static class ThumbCache
        {
            private class CacheEntry
            {
                public Image Image;
                public DateTime LastHitUtc;
            }

            private static readonly object _lock = new object();
            private static readonly Dictionary<string, CacheEntry> _cache =
                new Dictionary<string, CacheEntry>(StringComparer.OrdinalIgnoreCase);
            private static readonly Dictionary<string, Task<Image>> _tasks =
                new Dictionary<string, Task<Image>>(StringComparer.OrdinalIgnoreCase);

            private static readonly Semaphore _throttle = new Semaphore(4, 4); // 并发 4
            private const int Capacity = 300;

            static ThumbCache()
            {
                EnableTls12();
            }

            private static string MakeKey(string url, int h)
            {
                return url + "#h=" + h.ToString();
            }

            public static bool TryGet(string url, int targetHeight, out Image image)
            {
                string key = MakeKey(url, targetHeight);
                lock (_lock)
                {
                    CacheEntry e;
                    if (_cache.TryGetValue(key, out e) && e != null && e.Image != null)
                    {
                        e.LastHitUtc = DateTime.UtcNow;
                        _cache[key] = e;
                        image = e.Image;
                        return true;
                    }
                }
                image = null;
                return false;
            }

            public static void GetOrCreateAsync(string url, int targetHeight, System.Windows.Forms.Control uiInvoker, Action onReady)
            {
                string key = MakeKey(url, targetHeight);

                lock (_lock)
                {
                    if (_cache.ContainsKey(key))
                    {
                        BeginInvokeSafe(uiInvoker, onReady);
                        return;
                    }

                    Task<Image> exist;
                    if (_tasks.TryGetValue(key, out exist))
                    {
                        exist.ContinueWith(delegate { BeginInvokeSafe(uiInvoker, onReady); }, TaskScheduler.Default);
                        return;
                    }

                    Task<Image> task = Task.Factory.StartNew<Image>(delegate
                    {
                        _throttle.WaitOne();
                        try
                        {
                            byte[] bytes = DownloadBytes(url);
                            if (bytes == null) return null;
                            using (Bitmap src = BytesToBitmap(bytes))
                            {
                                return ScaleBitmap(src, targetHeight);
                            }
                        }
                        catch { return null; }
                        finally { try { _throttle.Release(); } catch { } }
                    }, CancellationToken.None, TaskCreationOptions.None, TaskScheduler.Default).ContinueWith<Image>(delegate (Task<Image> t)
                    {
                        Image result = t.Result;
                        lock (_lock)
                        {
                            _tasks.Remove(key);
                            if (result != null)
                            {
                                _cache[key] = new CacheEntry { Image = result, LastHitUtc = DateTime.UtcNow };
                                TrimIfNeededUnsafe();
                            }
                        }
                        return result;
                    }, TaskScheduler.Default);

                    _tasks[key] = task;
                    task.ContinueWith(delegate { BeginInvokeSafe(uiInvoker, onReady); }, TaskScheduler.Default);
                }
            }

            private static void TrimIfNeededUnsafe()
            {
                if (_cache.Count <= Capacity) return;
                List<KeyValuePair<string, CacheEntry>> list = _cache.ToList();
                list.Sort(delegate (KeyValuePair<string, CacheEntry> a, KeyValuePair<string, CacheEntry> b)
                {
                    return a.Value.LastHitUtc.CompareTo(b.Value.LastHitUtc);
                });
                int removeCount = Math.Max(1, Capacity / 10);
                for (int i = 0; i < removeCount && i < list.Count; i++)
                {
                    string k = list[i].Key;
                    CacheEntry e;
                    if (_cache.TryGetValue(k, out e))
                    {
                        _cache.Remove(k);
                        try { if (e.Image != null) e.Image.Dispose(); } catch { }
                    }
                }
            }
        }

        // ===== 原图缓存实现（容量更小） =====
        private static class FullCache
        {
            private class CacheEntry
            {
                public Image Image;
                public DateTime LastHitUtc;
            }

            private static readonly object _lock = new object();
            private static readonly Dictionary<string, CacheEntry> _cache =
                new Dictionary<string, CacheEntry>(StringComparer.OrdinalIgnoreCase);
            private static readonly Dictionary<string, Task<Image>> _tasks =
                new Dictionary<string, Task<Image>>(StringComparer.OrdinalIgnoreCase);

            private static readonly Semaphore _throttle = new Semaphore(2, 2); // 原图并发更小
            private const int Capacity = 50;

            static FullCache()
            {
                EnableTls12();
            }

            public static bool TryGet(string url, out Image image)
            {
                lock (_lock)
                {
                    CacheEntry e;
                    if (_cache.TryGetValue(url, out e) && e != null && e.Image != null)
                    {
                        e.LastHitUtc = DateTime.UtcNow;
                        _cache[url] = e;
                        image = e.Image;
                        return true;
                    }
                }
                image = null;
                return false;
            }

            public static void GetOrCreateAsync(string url, System.Windows.Forms.Control uiInvoker, Action<Image> onReady)
            {
                lock (_lock)
                {
                    Image cached;
                    if (TryGet(url, out cached))
                    {
                        BeginInvokeSafe(uiInvoker, delegate { onReady(cached); });
                        return;
                    }

                    Task<Image> exist;
                    if (_tasks.TryGetValue(url, out exist))
                    {
                        exist.ContinueWith(t => BeginInvokeSafe(uiInvoker, delegate { onReady(t.Result); }), TaskScheduler.Default);
                        return;
                    }

                    Task<Image> task = Task.Factory.StartNew<Image>(delegate
                    {
                        _throttle.WaitOne();
                        try
                        {
                            byte[] bytes = DownloadBytes(url);
                            if (bytes == null) return null;
                            using (Bitmap bmp = BytesToBitmap(bytes))
                            {
                                // 原图：不缩放，复制一份避免流依赖
                                return CopyBitmap(bmp);
                            }
                        }
                        catch { return null; }
                        finally { try { _throttle.Release(); } catch { } }
                    }, CancellationToken.None, TaskCreationOptions.None, TaskScheduler.Default).ContinueWith<Image>(delegate (Task<Image> t)
                    {
                        Image result = t.Result;
                        lock (_lock)
                        {
                            _tasks.Remove(url);
                            if (result != null)
                            {
                                _cache[url] = new CacheEntry { Image = result, LastHitUtc = DateTime.UtcNow };
                                TrimIfNeededUnsafe();
                            }
                        }
                        return result;
                    }, TaskScheduler.Default);

                    _tasks[url] = task;
                    task.ContinueWith(t => BeginInvokeSafe(uiInvoker, delegate { onReady(t.Result); }), TaskScheduler.Default);
                }
            }

            private static void TrimIfNeededUnsafe()
            {
                if (_cache.Count <= Capacity) return;
                List<KeyValuePair<string, CacheEntry>> list = _cache.ToList();
                list.Sort(delegate (KeyValuePair<string, CacheEntry> a, KeyValuePair<string, CacheEntry> b)
                {
                    return a.Value.LastHitUtc.CompareTo(b.Value.LastHitUtc);
                });
                int removeCount = Math.Max(1, Capacity / 10);
                for (int i = 0; i < removeCount && i < list.Count; i++)
                {
                    string k = list[i].Key;
                    CacheEntry e;
                    if (_cache.TryGetValue(k, out e))
                    {
                        _cache.Remove(k);
                        try { if (e.Image != null) e.Image.Dispose(); } catch { }
                    }
                }
            }
        }

        // ===== 共享底层工具 =====
        private static void EnableTls12()
        {
            try
            {
                const System.Security.Authentication.SslProtocols _Tls12 =
                    (System.Security.Authentication.SslProtocols)0x00000C00;
                ServicePointManager.SecurityProtocol |= (SecurityProtocolType)_Tls12;
            }
            catch { }
        }

        private static byte[] DownloadBytes(string url)
        {
            using (WebClient wc = new WebClient())
            {
                return wc.DownloadData(url);
            }
        }

        private static Bitmap BytesToBitmap(byte[] bytes)
        {
            using (MemoryStream ms = new MemoryStream(bytes))
            {
                // 为避免对流的依赖，先 Image.FromStream，再复制
                using (Image img = Image.FromStream(ms))
                {
                    return new Bitmap(img);
                }
            }
        }

        private static Image ScaleBitmap(Bitmap src, int targetHeight)
        {
            int h = targetHeight <= 0 ? 30 : targetHeight;
            if (h < 18) h = 18;
            double ratio = (double)h / (double)src.Height;
            int w = (int)Math.Round((double)src.Width * ratio);
            if (w < 1) w = 1;
            return new Bitmap(src, new Size(w, h));
        }

        private static Image CopyBitmap(Bitmap src)
        {
            return new Bitmap(src);
        }

        private static void BeginInvokeSafe(System.Windows.Forms.Control c, Action action)
        {
            if (action == null) return;
            try
            {
                if (c != null && !c.IsDisposed)
                    c.BeginInvoke(action);
                else
                    action();
            }
            catch
            {
                try { action(); } catch { }
            }
        }
    }
}