using FastReport.Controls;
using FastReport.Editor.Syntax.Parsers;
using FastReport.Engine;
using FastReport.Utils;
using ICSharpCode.AvalonEdit.CodeCompletion;
using ICSharpCode.AvalonEdit.Document;
using ICSharpCode.AvalonEdit.Editing;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Windows.Forms;

namespace FastReport.Design.PageDesigners.Code
{
    partial class AvalonSyntaxEditor
    {
        private void DoCodeCompletion(CompletionEventArgs e)
        {
            List<string> parts = e.Text.Split('.').ToList();
            string filter = "";
            
            if (e.Action == CompletionAction.CtrlSpacePressed)
            {
                // last item is incomplete - we will use it as a filter
                if (parts.Count > 0)
                {
                    filter = parts[parts.Count - 1];
                    parts.RemoveAt(parts.Count - 1);
                }
            }
            
            if (parts.Count == 0)
            {
                // list all report objects
                var list = new List<NamedItem>();
                foreach (Base obj in report.AllObjects)
                {
                    if (string.IsNullOrEmpty(obj.Name))
                        continue;
                    list.Add(new NamedItem(obj.Name, obj.GetType()));
                }

                list.Add(new NamedItem("Report", typeof(Report)));
                list.Add(new NamedItem("Engine", typeof(ReportEngine)));
                list.Sort((x, y) => x.Name.CompareTo(y.Name));
                
                foreach (var obj in list)
                {
                    if (obj.Name.IndexOf(filter, StringComparison.InvariantCultureIgnoreCase) == -1)
                        continue;

                    string description = obj.Type.Name + " " + obj.Name;
                    System.Drawing.Image image = null;
                    var objInfo = RegisteredObjects.FindObject(obj.Type);
                    if (objInfo != null)
                        image = report.Designer.GetImage(objInfo.ImageIndex);

                    e.CompletionData.Add(new CompletionData(obj.Name, description, image));
                }
            }
            else
            {
                Type rootType = null;

                // report object
                object root = report.FindObject(parts[0]);
                if (root != null)
                    rootType = root.GetType();
                else
                {
                    // some frequently used types like Color?
                    if (parts[0] == "Color")
                        rootType = typeof(System.Drawing.Color);
                    else if (parts[0] == "Report")
                        rootType = typeof(Report);
                    else if (parts[0] == "Engine")
                        rootType = typeof(ReportEngine);
                }

                if (rootType != null)
                {
                    for (int i = 1; i < parts.Count; i++)
                    {
                        PropertyInfo member = null;
                        try
                        {
                            member = rootType.GetProperty(parts[i]);
                        }
                        catch 
                        { 
                            // ambiguous properties found, take first one
                            member = rootType.GetProperties().Where(x => x.Name == parts[i]).FirstOrDefault();
                        }
                        if (member != null)
                            rootType = member.PropertyType;
                        else
                        {
                            rootType = null;
                            break;
                        }
                    }
                }

                if (rootType != null)
                {
                    if (e.Action == CompletionAction.EqualEntered)
                    {
                        if (rootType.IsEnum)
                        {
                            // list enum members
                            foreach(var name in Enum.GetNames(rootType))
                            {
                                var fieldInfo = rootType.GetField(name);
                                e.CompletionData.Add(new CompletionData(rootType.Name + "." + name, ReflectionRepository.DescriptionHelper.GetDescription(fieldInfo), null));
                            }
                        }
                    }
                    else
                    {
                        var members = rootType.GetMembers(BindingFlags.Public | BindingFlags.Instance | BindingFlags.Static).ToList();
                        members.Sort((x, y) => (x.Name.CompareTo(y.Name)));
                        foreach (var member in members)
                        {
                            if (!string.IsNullOrEmpty(filter) && member.Name.IndexOf(filter, StringComparison.InvariantCultureIgnoreCase) == -1)
                                continue;

                            string description = "";
                            System.Drawing.Image image = null;
                            if (member.MemberType == MemberTypes.Property)
                            {
                                var propInfo = member as PropertyInfo;

                                image = report.Designer.GetImage(78);
                                description = report.CodeHelper.GetPropertySignature(propInfo, true);
                                description += "<br/>" + ReflectionRepository.DescriptionHelper.GetDescription(member);
                            }
                            else if (member.MemberType == MemberTypes.Method)
                            {
                                var methodInfo = member as MethodInfo;
                                if (methodInfo.IsSpecialName)
                                    continue;

                                image = report.Designer.GetImage(199);
                                description = report.CodeHelper.GetMethodSignature(methodInfo, true);
                                description += "<br/>" + ReflectionRepository.DescriptionHelper.GetDescription(methodInfo);
                                description += "<br/>";

                                foreach (ParameterInfo parInfo in methodInfo.GetParameters())
                                {
                                    // special case - skip "thisReport" parameter
                                    if (parInfo.Name == "thisReport")
                                        continue;

                                    string s = ReflectionRepository.DescriptionHelper.GetDescription(parInfo);
                                    s = s.Replace("<b>", "{i}").Replace("</b>:", "{/i}").Replace("&", "&amp;").Replace("<", "&lt;").Replace(">", "&gt;").Replace("{i}", "<i>").Replace("{/i}", "</i>");
                                    description += "<br/>" + s + "<br/>";
                                }
                                description = description.Replace("\t", "<br/>");
                            }
                            else
                            {
                                continue;
                            }

                            if (description.EndsWith("<br/>"))
                                description = description.Substring(0, description.Length - 5);
                            e.CompletionData.Add(new CompletionData(member.Name, description, image));
                        }
                    }
                }
            }
        }

        private class NamedItem
        {
            public string Name { get; }
            public Type Type { get; }

            public NamedItem(string name, Type type)
            {
                Name = name;
                Type = type;
            }
        }

        private class CompletionData : ICompletionData
        {
            private string htmlDescription;
            private HtmlDescriptionTextBlock descriptionTextBlock;

            public CompletionData(string text, string htmlDescription, System.Drawing.Image image)
            {
                this.Text = text;
                this.htmlDescription = htmlDescription;
                this.Image = Helper.GetImage(image);
            }

            public System.Windows.Media.ImageSource Image { get; }

            public string Text { get; private set; }

            public object Content => this.Text;

            public object Description
            {
                get
                {
                    if (descriptionTextBlock == null)
                        CreateTextBlock();
                    return descriptionTextBlock;
                }
                set { }
            }

            public double Priority => 0;

            public void Complete(TextArea textArea, ISegment completionSegment, EventArgs insertionRequestEventArgs)
            {
                textArea.Document.Replace(completionSegment, this.Text);
            }

            private void CreateTextBlock()
            {
                descriptionTextBlock = new HtmlDescriptionTextBlock();
                descriptionTextBlock.Image = this.Image;
                descriptionTextBlock.Description = this.htmlDescription;
                descriptionTextBlock.ParseDescription();
            }
        }
    }
}