using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Windows.Controls;
using System.Windows.Data;
using HeuristicLab.BackgroundProcessing;
using System.ComponentModel;
using System.Windows;
using System.IO;
using System.Threading;
using System.Collections.Specialized;
using HeuristicLab.MainForm.WPF;
using HeuristicLab.OKB.Cockpit.Query.OKBQuery;
using HeuristicLab.MainForm;
using HeuristicLab.OKB.Client;

namespace HeuristicLab.OKB.Cockpit.Query {

  public partial class RunView : UserControl, IAutoView, IOKBCockpitItem {

    private object selectorRefreshLock = new object();
    private AttributeSelectors attributeSelectors;
    private DataTable runTable;
    private List<AttributeSelector> selectors = null;
    private ManualResetEvent selectorsInitialized = new ManualResetEvent(false);

    public RunView() {
      InitializeComponent();
      attributeSelectors = new AttributeSelectors();
      GridView view = (GridView)Runs.View;
      attributeSelectors.CollectionChanged += (sender, args) => {
        if (args.Action == NotifyCollectionChangedAction.Add) {
          foreach (AttributeSelector selector in args.NewItems) {
            GridViewColumn column = new GridViewColumn() {
              Header = selector,
              DisplayMemberBinding = new Binding(selector.ColumnName),
            };
            view.Columns.Add(column);
            selector.PropertyChanged += (s, a) => {
              if (a.PropertyName == "ColumnName") {
                column.DisplayMemberBinding = new Binding(selector.ColumnName);
              }
              Validate();
            };
          }
        } else if (args.Action == NotifyCollectionChangedAction.Remove) {
          foreach (AttributeSelector selector in args.OldItems) {
            view.Columns.Remove(view.Columns.First(i => i.Header == selector));
          }
        }
      };
      attributeSelectors.Add(new AttributeSelector("Run", "Id", typeof(int)));
      attributeSelectors.Add(new AttributeSelector("Run", "FinishedDate", typeof(DateTime)));
      attributeSelectors.Add(new AttributeSelector("Algorithm", "Name", typeof(string)));
      attributeSelectors.Add(new AttributeSelector("Problem", "Name", typeof(string)));
      attributeSelectors.Add(new AttributeSelector("SolutionRepresentation", "Name", typeof(string)));
      RefreshSelectors();
    }

    #region IView Members

    public string Caption {
      get { return "Run View"; }
      set { throw new NotSupportedException(); }
    }

    public event EventHandler CaptionChanged;

    public event EventHandler Changed;

    protected void OnChanged() {
      EventHandler handler = CaptionChanged;
      if (handler != null)
        handler(this, EventArgs.Empty);
    }

    public virtual void Close() {
      MainFormManager.GetMainForm<WPFMainFormBase>().CloseView(this);
      IsShown = false;
    }

    public void Hide() {
      MainFormManager.GetMainForm<WPFMainFormBase>().HideView(this);
      IsShown = false;
    }

    public bool IsShown { get; protected set; }

    private bool readOnly = false;
    public bool ReadOnly {
      get {
        return readOnly;
      }
      set {
        if (value == readOnly) return;
        readOnly = value;
        OnReadOnlyChanged();
      }
    }
    public event EventHandler ReadOnlyChanged;
    protected void OnReadOnlyChanged() {
      EventHandler handler = ReadOnlyChanged;
      if (handler != null)
        handler(this, EventArgs.Empty);
    }

    public void Show() {
      MainFormManager.GetMainForm<WPFMainFormBase>().ShowView(this);
      IsShown = true;
    }

    #endregion

    protected void OnAddClicked(object sender, EventArgs args) {
      AddItem();
    }

    protected void OnCheckClicked(object sender, EventArgs args) {
      var loader = new ObservableBackgroundWorker("Checking Runs");
      int? count = null;
      bool failed = false;
      loader.DoWork += (snd, arg) => {
        try {
          QueryServiceClient client = ClientFactory.Create<QueryServiceClient, IQueryService>();
          client.PrepareQuery(attributeSelectors.ToList());
          count = client.GetCount();
          client.Terminate();
          client.Close();
        } catch {
          failed = true;
        }
      };
      loader.RunWorkerCompleted += (snd, arg) => {
        if (failed) {
          NrOfRunsLabel.Text = "?";
          MessageBox.Show("Checking runs failed.", Caption);
        } else {
          NrOfRunsLabel.Text = count.ToString();
        }
      };
      loader.RunWorkerAsync();
    }


    private void RefreshSelectors() {
      ObservableBackgroundWorker loader = new ObservableBackgroundWorker("Fetching DB schema");
      bool failed = false;
      loader.DoWork += (s, a) => {
        try {
          QueryServiceClient client = ClientFactory.Create<QueryServiceClient, IQueryService>();
          selectors = client.GetAllAttributeSelectors();
        } catch {
          failed = true;
        } finally {
          selectorsInitialized.Set();
        }
      };
      loader.RunWorkerCompleted += (s, a) => {
        if (failed) {
          if (MessageBox.Show(
                "Could not fetch DB Schema. Retry?", Caption,
                MessageBoxButton.OKCancel) == MessageBoxResult.OK) {
            selectorsInitialized.Reset();
            RefreshSelectors();
          }
        }
      };
      loader.RunWorkerAsync();
    }

    protected void AddItem() {
      BackgroundWorker waiter = new BackgroundWorker();
      waiter.DoWork += (s, a) => selectorsInitialized.WaitOne();
      waiter.RunWorkerCompleted += (s, a) => {
        if (!VerifySelectors())
          return;
        var selector = new AttributeSelectorWindow(selectors) {
          Owner = MainFormManager.GetMainForm<CockpitMainWindow>(),
        };
        if (selector.ShowDialog() == true) {
          attributeSelectors.Add(selector.AttributeSelector);
        }
      };
      waiter.RunWorkerAsync();
    }

    private bool VerifySelectors() {
      if (selectors == null &&
          MessageBox.Show(
            "Schema information not available. Retry?",
            this.Caption, MessageBoxButton.OKCancel) == MessageBoxResult.OK) {
        selectorsInitialized.Reset();
        RefreshSelectors();
        return false;
      }
      return true;
    }

    protected void OnUpdateClicked(object sender, EventArgs args) {
      var loader = new ObservableBackgroundWorker("Preparing Query") {
        WorkerReportsProgress = true,
        WorkerSupportsCancellation = true,
      };
      int total = 0;
      loader.DoWork += (snd, arg) => {
        loader.ReportProgress(0);
        QueryServiceClient client = ClientFactory.Create<QueryServiceClient, IQueryService>();
        runTable = client.PrepareQuery(attributeSelectors.ToList());
        loader.ReportProgress(50);
        total = client.GetCount();
        int stepSize = Math.Max(1, Math.Min(total / 100, 100));
        loader.ReportProgress(100);
        Thread.Sleep(0);
        loader.Name = "Loading Runs";
        loader.ReportProgress(0);
        if (total > 0) {
          DataTable newRows = new DataTable();
          do {
            newRows = client.GetNextRows(stepSize);
            runTable.Merge(newRows);
            loader.ReportProgress(100 * runTable.Rows.Count / total);
          } while (!loader.CancellationPending && newRows.Rows.Count > 0);
        }
        client.Terminate();
        client.Close();
        loader.ReportProgress(100);
      };
      loader.RunWorkerCompleted += (snd, arg) => {
        if (arg.Error == null) {
          NrOfRunsLabel.Text = total.ToString();
          for (int i = 0; i < runTable.Columns.Count; i++) {
            attributeSelectors[i].ColumnName = runTable.Columns[i].ColumnName;
          }
          Runs.DataContext = runTable;
          Runs.SetBinding(ListView.ItemsSourceProperty, new Binding());
        } else {
          NrOfRunsLabel.Text = "?";
        }
      };
      loader.RunWorkerAsync();
    }

    protected void ContextMenuClicked(object sender, RoutedEventArgs args) {
      ContextMenu menu = sender as ContextMenu;
      MenuItem item = args.Source as MenuItem;
      AttributeSelector selector = menu.Tag as AttributeSelector;
      if (menu == null || item == null || selector == null)
        return;
      if (item.Name == "ConfigureItem") {
        BackgroundWorker waiter = new BackgroundWorker();
        waiter.DoWork += (s, a) => selectorsInitialized.WaitOne();
        waiter.RunWorkerCompleted += (s, a) => {
          if (!VerifySelectors())
            return;
          var selectorView = new AttributeSelectorWindow(selectors) {
            Owner = MainFormManager.GetMainForm<CockpitMainWindow>(),
            AttributeSelector = selector,
          };
          selectorView.ShowDialog();
        };
        waiter.RunWorkerAsync();
      } else if (item.Name == "RemoveItem") {
        attributeSelectors.Remove(selector);
      } else if (item.Name == "AddColumn") {
        AddItem();
      }
    }

    protected void OnCopyClicked(object sender, RoutedEventArgs args) {
      ObservableBackgroundWorker copier = new ObservableBackgroundWorker("Copying to Clipboard") {
        WorkerReportsProgress = true,
        WorkerSupportsCancellation = true
      };
      StringBuilder sb = new StringBuilder();
      copier.DoWork += (s, a) => {
        sb.Append(
          string.Join("\t",
            runTable.Columns.Cast<DataColumn>()
            .Select(c => c.ColumnName)
            .ToArray()))
          .Append('\n');
        int i = 0;
        int lastProgress = 0;
        foreach (DataRow row in runTable.Rows) {
          sb.Append(string.Join("\t", row.ItemArray.Select(v => v.ToString()).ToArray())).Append('\n');
          i++;
          int progress = 100 * i / runTable.Rows.Count;
          if (progress > lastProgress) {
            copier.ReportProgress(progress);
            lastProgress = progress;
            Thread.Sleep(0);
          }
          if (copier.CancellationPending) {
            a.Cancel = true;
            break;
          }
        }
      };
      copier.RunWorkerCompleted += (s, a) => {
        if (!a.Cancelled)
          Clipboard.SetText(sb.ToString(), TextDataFormat.Text);
      };
      copier.RunWorkerAsync();
    }

    protected void Validate() {
      CheckButton.IsEnabled = UpdateButton.IsEnabled = attributeSelectors.All(s => s.IsValid);
      if (CheckButton.IsEnabled) {
        ErrorMessages.Text = "";
      } else {
        ErrorMessages.Text = "Invalid attribute selector configuration";
      }
    }
  }
}