using FastReport.Controls;
using FastReport.Utils;
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;

namespace FastReport.Design.ToolWindows
{
    /// <summary>
    /// Represents the "Report Tree" window.
    /// </summary>
    public class ReportTreeWindow : FilterableToolWindow
    {
        #region Fields
        private Dictionary<Base, TreeNode> objectNodes;
        private Panel dragIndicator;
        private ToolbarButton btnSync;
        #endregion

        #region Private Methods
        private void UpdateSelection()
        {
            if (Designer.SelectedObjects == null || Designer.SelectedObjects.Count == 0)
                return;

            if (objectNodes.ContainsKey(Designer.SelectedObjects[0]))
            {
                ObjectsToSelectedNodes();
            }
        }

        private void ObjectsToSelectedNodes()
        {
            var nodes = new List<TreeNode>();
            foreach (Base b in Designer.SelectedObjects)
                nodes.Add(objectNodes[b]);
            tree.SelectedNodes = nodes;
            if (btnSync.Checked)
                tree.TrackSelection();
        }

        private void SelectedNodesToObjects()
        {
            Designer.SelectedObjects.Clear();
            foreach (var node in tree.SelectedNodes)
                Designer.SelectedObjects.Add(node.Tag as Base);

            // activate object's page
            if (Designer.SelectedObjects.Count > 0)
            {
                var c = Designer.SelectedObjects[0];
                if (!(c is Report))
                    Designer.ActiveReportTab.ActivePage = c.Page;
            }

            Designer.SelectionChanged(this);
        }

        private void EnumComponents(Base rootComponent, TreeNodeCollection rootNode)
        {
            string name = rootComponent is Report ?
              "Report - " + Designer.ActiveReportTab.ReportName : rootComponent.Name;
            TreeNode node = rootNode.Add(name);
            node.Tag = rootComponent;

            objectNodes[rootComponent] = node;

            int imageIndex = rootComponent.GetImageIndex();
            if (imageIndex != -1)
            {
                node.ImageIndex = imageIndex;
                node.SelectedImageIndex = imageIndex;
            }

            if (rootComponent.HasFlag(Flags.CanShowChildrenInReportTree))
            {
                foreach (Base component in rootComponent.ChildObjects)
                    EnumComponents(component, node.Nodes);
            }
        }

        private bool CheckChanges(Base rootComponent, TreeNode rootNode)
        {
            if (rootNode.Tag != rootComponent)
                return false;
            if (!(rootComponent is Report))
            {
                if (rootNode.Text != rootComponent.Name)
                    return false;
            }
            if (!rootComponent.HasFlag(Flags.CanShowChildrenInReportTree))
                return true;

            ObjectCollection childObjects = rootComponent.ChildObjects;
            if (childObjects.Count != rootNode.Nodes.Count)
                return false;
            for (int i = 0; i < childObjects.Count; i++)
            {
                if (!CheckChanges(childObjects[i], rootNode.Nodes[i]))
                    return false;
            }
            return true;
        }

        private void tree_SelectionChanged(object sender, EventArgs e)
        {
            SelectedNodesToObjects();
        }

        private void tree_RightMouseButtonClicked(object sender, MouseEventArgs e)
        {
            var menu = Designer.SelectedObjects[0].GetContextMenu();
            menu?.Show(tree, e.Location);
        }

        private void tree_ItemDrag(object sender, ItemDragEventArgs e)
        {
            // check if every item can be dragged
            var effect = DragDropEffects.Move;
            foreach (Base draggedItem in Designer.SelectedObjects)
            {
                if (draggedItem is ComponentBase &&
                    (draggedItem.IsAncestor || draggedItem.HasFlag(Flags.CanChangeParent)))
                {
                    // ok
                }
                else
                {
                    effect = DragDropEffects.None;
                    break;
                }
            }
            tree.DoDragDrop(e.Item, effect);
        }

        private void tree_DragOver(object sender, DragEventArgs e)
        {
            dragIndicator.Hide();

            TreeNode targetNode = (tree.GetNodeAt(tree.PointToClient(new Point(e.X, e.Y))));
            if (targetNode == null || e.AllowedEffect == DragDropEffects.None)
                return;

            Base target = targetNode.Tag as Base;

            // allowed moves are:
            // - target is not dragged
            // - target is not child of dragged
            // - dragged is not child of parent
            // - target can contain dragged, or 
            // parent of target can contain dragged

            int dragPos = 0;
            int allow = 0;
            foreach (Base dragged in Designer.SelectedObjects)
            {
                if (dragged == target || target.HasParent(dragged) || dragged.Parent == target)
                    continue;

                bool changeParent = (target as IParent)?.CanContain(dragged) ?? false;
                bool changeOrder = (target.Parent as IParent)?.CanContain(dragged) ?? false;
                if (changeParent || changeOrder)
                {
                    allow++;
                    dragPos = changeParent ? targetNode.Bounds.Bottom : targetNode.Bounds.Top;
                }
            }

            if (allow == Designer.SelectedObjects.Count)
            {
                e.Effect = e.AllowedEffect;
                dragIndicator.BackColor = tree.ForeColor;
                dragIndicator.SetBounds(tree.Left + targetNode.Bounds.Left, tree.Top + dragPos, targetNode.Bounds.Width, Designer.LogicalToDevice(2));
                dragIndicator.Show();
            }
        }

        private void tree_DragDrop(object sender, DragEventArgs e)
        {
            dragIndicator.Hide();

            TreeNode targetNode = tree.GetNodeAt(tree.PointToClient(new Point(e.X, e.Y)));
            Base target = targetNode.Tag as Base;

            // cases: 
            // - target can contain dragged. Just change parent.
            // - target cannot contain dragged. Change creation order (Z-order).

            foreach (Base dragged in Designer.SelectedObjects)
            {
                if (target is IParent par && par.CanContain(dragged))
                {
                    dragged.Parent = target;
                }
                else
                {
                    Base parent = target.Parent;
                    dragged.Parent = parent;
                    dragged.ZOrder = target.ZOrder;
                }
            }

            // update all designer plugins (this one too)
            Designer.SetModified(null, "ChangeParent");
        }

        private void tree_DragLeave(object sender, EventArgs e)
        {
            dragIndicator.Hide();
        }

        private void tree_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.Delete)
                Designer.cmdDelete.Invoke();
        }

        private void tree_BeforeLabelEdit(object sender, NodeLabelEditEventArgs e)
        {
            Base c = e.Node.Tag as Base;
            if (c is Report)
                e.CancelEdit = true;
        }

        private void tree_AfterLabelEdit(object sender, NodeLabelEditEventArgs e)
        {
            if (e.Label != null)
            {
                Base c = e.Node.Tag as Base;
                try
                {
                    c.Name = e.Label;
                    Designer.SetModified(this, "Change");
                }
                catch (Exception ex)
                {
                    FRMessageBox.Error(ex.Message);
                    e.CancelEdit = true;
                }
            }
        }

        private void btnSync_Click(object sender, EventArgs e)
        {
            tree.TrackSelection();
        }

        #endregion

        #region Protected/Public Methods
        /// <inheritdoc/>
        protected override void UpdateTree()
        {
            // if there was no changes in the report structure, do nothing
            if (Designer.ActiveReport != null && tree.Nodes.Count > 0)
            {
                if (CheckChanges(Designer.ActiveReport, tree.Nodes[0]))
                    return;
            }

            tree.BeginUpdate();
            tree.Nodes.Clear();
            objectNodes.Clear();
            if (Designer.ActiveReport != null)
                EnumComponents(Designer.ActiveReport, tree.Nodes);
            tree.ExpandAll();
            tree.EndUpdate();
        }

        /// <inheritdoc/>
        public override void SelectionChanged()
        {
            Throttle.Execute(UpdateSelection);
        }

        /// <inheritdoc/>
        public override void UpdateContent()
        {
            Throttle.Execute(() =>
            {
                UpdateTree();
                UpdateSelection();
#if !WPF
                SearchMatches();
#endif
            });
        }

        /// <inheritdoc/>
        public override void Localize()
        {
            base.Localize();
            MyRes res = new MyRes("Designer,ToolWindow,ReportTree");
            Text = res.Get("");
            btnSync.ToolTipText = res.Get("Sync");
        }

        /// <inheritdoc/>
        public override void UpdateDpiDependencies()
        {
            base.UpdateDpiDependencies();
            Image = Designer.GetImage(189);
            tree.ImageList = Designer.GetImages();
        }
        #endregion

        /// <summary>
        /// Initializes a new instance of the <see cref="ReportTreeWindow"/> class with default settings.
        /// </summary>
        /// <param name="designer">The report designer.</param>
        public ReportTreeWindow(Designer designer) : base(designer)
        {
            Name = "ReportTreeWindow";
            objectNodes = new Dictionary<Base, TreeNode>();

            tree.LabelEdit = true;
            tree.ShowRootLines = false;
            tree.AllowDrop = true;
            tree.SelectionChanged += tree_SelectionChanged;
            tree.RightMouseButtonClicked += tree_RightMouseButtonClicked;
            tree.ItemDrag += tree_ItemDrag;
            tree.DragOver += tree_DragOver;
            tree.DragDrop += tree_DragDrop;
            tree.DragLeave += tree_DragLeave;
            tree.KeyDown += tree_KeyDown;
            tree.BeforeLabelEdit += tree_BeforeLabelEdit;
            tree.AfterLabelEdit += tree_AfterLabelEdit;

            btnSync = AddButton(81, btnSync_Click);
            btnSync.CheckOnClick = true;

            toolbar.AddItems(btnSync);

            dragIndicator = new Panel();
            dragIndicator.Visible = false;

            Controls.Add(dragIndicator);
            Controls.SetChildIndex(dragIndicator, 0);

            Localize();
            UpdateDpiDependencies();
        }
    }
}