using UnityEngine;
using UnityEngine.Assertions;
using UnityEngine.UI;

namespace Google.Maps.Examples.Shared {
  /// <summary>
  /// This class controls the behavior of the instructions panel.
  /// It also adjusts the instructions displayed on screen based on the platform where
  /// the example is running.
  ///
  /// The Instructions component has two states controlled by the help button.
  /// When the button is clicked on, the instruction dialog is displayed,
  /// and The help button is disabled.
  /// When the dialog is closed, we re-activate the help button.
  ///
  /// This approach optimizes the UI real estate for the example.
  ///
  /// </summary>
  public class InstructionsHandler : MonoBehaviour {
    /// <summary>
    /// Information text adjusted depending on deployed platform.
    /// </summary>
    public Text InstructionsText;
    /// <summary>
    /// Dialog box controlled by the help button.
    /// </summary>
    public GameObject InstructionsDialog;
    /// <summary>
    /// Reference to Help button.
    /// </summary>
    public GameObject HelpButton;
    /// <summary>
    /// Glass panel used to block events when dialog is on.
    /// </summary>
    public GameObject GlassPanel;

    [Multiline]
    public string InstructionsContent =
        "Arrow keys for pitch and yaw.\nWSAD to move.\nQE for height." +
        "\n\nClick anywhere to close.";

    /// <summary>
    /// At start, update the instructions text based on the target platform,
    /// and hide the Instructions Dialog.
    /// </summary>
    private void Start() {
      Assert.IsNotNull(InstructionsText, "Instructions Text is not set!");
      Assert.IsNotNull(InstructionsDialog, "Instructions Dialog is not set!");
      Assert.IsNotNull(HelpButton, "Help button is not set!");
      Assert.IsNotNull(GlassPanel, "GlassPanel is not set!");

      InstructionsText.text = InstructionsContent;

      #if (UNITY_IOS || UNITY_ANDROID) && !UNITY_EDITOR
      InstructionsText.text =
      "Drag knob to move and rotate.\nUp and Down buttons for elevation." +
      "\nGyroscope for pitch. \nPinch screen to zoom.\n\nTap anywhere to close.";
      #endif

      ShowHideDialog(false);
    }

    /// <summary>
    /// Event triggered when the help button is clicked on.
    /// </summary>
    public void OnClick() {
      ShowHideDialog(true);
    }

    /// <summary>
    /// Event triggered by any click/touch on the glass panel.
    /// </summary>
    public void OnClose() {
      ShowHideDialog(false);
    }

    /// <summary>
    /// Helper function to hide or show the dialog panel and its associated elements.
    /// </summary>
    /// <param name="isVisible">Indicates if dialog should be visible or hidden.</param>
    private void ShowHideDialog(bool isVisible) {
      HelpButton.SetActive(!isVisible);
      InstructionsDialog.SetActive(isVisible);
      GlassPanel.SetActive(isVisible);
    }
  }
}