using System;

namespace Framework.Dialogue2 {

  /// <summary>Provides helper methods for dealing with dialogue canvases</summary>
  public static class DialogueCanvasHelper {

    #region class DialogueText

    /// <summary>Dialogue text container without any extras</summary>
    private class DialogueText : IDialogueText {

      /// <summary>Initialized a new text element for dialogues</summary>
      /// <param name="text">Text that will be shown on the dialogue</param>
      public DialogueText(string text) {
        this.text = text;
      }

      /// <summary>Text that will be shown in the dialogue</summary>
      public string Text {
        get { return this.text; }
      }

      /// <summary>Text that will be shown in the dialogue</summary>
      private string text;

    }

    #endregion // class DialogueText

    /// <summary>Displays the dialogue canvas using only text for the dialogue</summary>
    /// <param name="canvas">Canvas on which dialogue will be shown</param>
    /// <param name="speech">Speech that will be shown on the canvas (can be null)</param>
    /// <param name="choices">Choices that will be available to the user (can be null)</param>
    /// <remarks>
    ///   This constructs a simple text-only IDialogueText wrapper around the passed strings.
    ///   It is useful for very simply dialogue and testing only. Actual games likely want
    ///   to display character portraits, names and other things with their dialogue and
    ///   need a custom object that decorates text with a wrapper providing these informations.
    /// </remarks>
    public static void Show(this IDialogueCanvas canvas, string speech, params string[] choices) {

      // Count the number of choices specified by the caller
      int choiceCount;
      {
        if(choices == null) {
          choiceCount = 0;
        } else {
          choiceCount = choices.Length;
        }
      }

      // If the caller specified no choices, use the speech-only invocation
      if(choiceCount == 0) {
        canvas.ShowSpeech(new DialogueText(speech));
      } else { // Choices specified

        // Wrap the choices in dialogue text elements
        var choiceTexts = new IDialogueText[choiceCount];
        for(int index = 0; index < choiceCount; ++index) {
          choiceTexts[index] = new DialogueText(choices[index]);
        }

        // If no speech was specified, use a choice-only dialogue
        if(string.IsNullOrEmpty(speech)) {
          canvas.ShowChoices(new ArraySegment<IDialogueText>(choiceTexts, 0, choiceCount));
        } else { // We have speech and choices
          canvas.ShowSpeechAndChoices(
            new DialogueText(speech),
            new ArraySegment<IDialogueText>(choiceTexts, 0, choiceCount)
          );
        }
      }

    }

  }

} // namespace Framework.Dialogue