using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using Sdl.FileTypeSupport.Framework.BilingualApi;
using Sdl.TranslationStudioAutomation.IntegrationApi.AutoSuggest;
using Sdl.TranslationStudioAutomation.IntegrationApi.Extensions;

namespace Sdl.AutoSuggest.Sample
{
    [AutoSuggestProvider(Id = "SourceCopyAutoSuggestProvider", Name = "AutoSuggest provider for copying the source words")]
    public class SourceCopyAutoSuggestProvider : AbstractAutoSuggestProvider
    {
        private List<string> _segmentWordSuggestCandidates;

        public SourceCopyAutoSuggestProvider()
        {
            // Set the default icon for the suggestions from this provider
            Icon = new Icon(SystemIcons.Exclamation, 16, 16);
        }

        #region AutoSuggestProvider Implementation
        /// <summary>
        /// This function is not necessary for this sample. It just shows in case you need dictionary or some other language specific action, you can do it here.
        /// </summary>
        protected override void OnActiveDocumentChanged()
        {
            if (ActiveDocument != null)
            {
                var sourceLanguage = ActiveDocument.Project.GetProjectInfo().SourceLanguage;
                var targetLanguage = ActiveDocument.Files.First().Language;

                System.Diagnostics.Debug.WriteLine("SourceCopyAutoSuggestProvider Language pair: {0}->{1}", sourceLanguage.DisplayName, targetLanguage.DisplayName);

                // in case you need prepare the dictionary for this language pair, do it here
            }
            else
            {
                _segmentWordSuggestCandidates = null;
            }

            System.Diagnostics.Debug.WriteLine("OnActiveDocumentChanged  {0}", ActiveDocument != null);
        }

        // when user goes to a segment, we want to prepare the AutoSuggest Candidate first. 
        // when it takes long, for performance reason, the execution might be done in a separate thread.
        protected override void OnActiveSegmentChanged()
        {
            if (Settings.Enabled)
            {
                PrepareSegmentSuggestCandiates();
            }
            else
            {
                _segmentWordSuggestCandidates = null;
            }
            System.Diagnostics.Debug.WriteLine("OnActiveSegmentChanged  {0}", ActiveSegmentPair != null);
        }

        /// <summary>
        /// We only provide the AutoSuggest when the candidate is available. The user might have the change from disabled to enabled, we need preapre the candidate.
        /// </summary>
        protected override void OnSettingsChanged()
        {
            if (Settings.Enabled)
            {
                PrepareSegmentSuggestCandiates();
            }
            else
            {
                _segmentWordSuggestCandidates = null;
            }
        }

        protected override IEnumerable<AbstractAutoSuggestResult> GetSuggestions(AbstractEditingContext context)
        {
            if (Settings.Enabled)
            {
                string suffix = context.GetAllPrefixes().First();
                if (!string.IsNullOrEmpty(suffix) && _segmentWordSuggestCandidates != null && _segmentWordSuggestCandidates.Count > 0)
                {
                    return _segmentWordSuggestCandidates
                        .Where(item => item.StartsWith(suffix, Settings.CaseSensitive ? StringComparison.InvariantCulture : StringComparison.InvariantCultureIgnoreCase))
                        .Select(item =>
                            {
                                var result = new AutoSuggestTextResult(context, item);
                                result.Priority = Settings.Priority;

                                // Set different icon for suggestions starting with "a". For the rest set the default provider icon
                                result.Icon = result.Text.StartsWith("a") ? new Icon(SystemIcons.Question, 16, 16) : Icon;

                                return result;
                            });
                }

            }
            return null;
        }

        #endregion

        private void PrepareSegmentSuggestCandiates()
        {
            if (ActiveSegmentPair != null)
            {
                var stringBuilder = new StringBuilder();
                foreach (var item in ActiveSegmentPair.Source.AllSubItems)
                {
                    var text = item as IText;
                    if (text != null)
                    {
                        stringBuilder.Append(text.Properties.Text);
                    }
                }

                // Split the sentence to words in a naive way, in practice a better way is needed to to tokenize the sentence.
                // As a sample we will show the source words in the AutoSuggest, in practice, translation to the target language are needed
                _segmentWordSuggestCandidates = Regex.Split(stringBuilder.ToString(), @"\W+").ToList();

                System.Diagnostics.Debug.WriteLine("PrepareSegmentSuggestCandiates: {0}", stringBuilder.ToString());
                System.Diagnostics.Debug.WriteLine("{0}", _segmentWordSuggestCandidates == null);
            }
        }

    }
}