using System;

using UnityEngine;

namespace Framework.Input.States {

  /// <summary>Gives an input action a default joystick axis</summary>
  [AttributeUsage(AttributeTargets.Field | AttributeTargets.Property, AllowMultiple = true)]
  public class DefaultJoystickAxisAttribute : Attribute {

    /// <summary>Initializes a new default joystick axis provider</summary>
    /// <param name="defaultAxis">
    ///   Joystick axis that will be bound to both the negative and positive side
    ///   of the action by default
    /// </param>
    public DefaultJoystickAxisAttribute(string defaultAxis) {
      if(!string.IsNullOrEmpty(defaultAxis)) {
        int lastCharacterIndex = defaultAxis.Length - 1;
        char lastCharacter = defaultAxis[lastCharacterIndex];
        if(lastCharacter == '-') {
          this.defaultPositiveAxis = new JoystickAxis(
            defaultAxis.Substring(0, lastCharacterIndex), true
          );
        } else if(lastCharacter == '+') {
          this.defaultPositiveAxis = new JoystickAxis(
            defaultAxis.Substring(0, lastCharacterIndex), false
          );
        } else {
          this.defaultNegativeAxis = new JoystickAxis(defaultAxis, true);
          this.defaultPositiveAxis = new JoystickAxis(defaultAxis, false);
        }
      }
    }

    /// <summary>Initializes a new default joystick axis provider</summary>
    /// <param name="defaultNegativeAxis">
    ///   Joystick axis that will be bound to the negative side of the action by default
    /// </param>
    /// <param name="defaultPositiveAxis">
    ///   Joystick axis that will be bound to the positive side of the action by default
    /// </param>
    public DefaultJoystickAxisAttribute(string defaultNegativeAxis, string defaultPositiveAxis) {
      if(!string.IsNullOrEmpty(defaultNegativeAxis)) { 
        this.defaultNegativeAxis = joystickAxisFromAxisName(defaultNegativeAxis);
      }
      if(!string.IsNullOrEmpty(defaultPositiveAxis)) {
        this.defaultPositiveAxis = joystickAxisFromAxisName(defaultPositiveAxis);
      }
    }

    /// <summary>
    ///   Default joystick axis that will be bound to the negative side of the axis
    /// </summary>
    public JoystickAxis DefaultNegativeAxis {
      get { return this.defaultNegativeAxis; }
    }

    /// <summary>
    ///   Default joystick axis that will be bound to the negative side of the axis
    /// </summary>
    public JoystickAxis DefaultPositiveAxis {
      get { return this.defaultPositiveAxis; }
    }

    /// <summary>Converts a joystick axis name with postfix into a joystick axis</summary>
    /// <param name="axisName">Name of the joystick axis with postfix</param>
    /// <returns>The matching joystick axis structure</returns>
    private static JoystickAxis joystickAxisFromAxisName(string axisName) {
      if(string.IsNullOrEmpty(axisName)) {
        return new JoystickAxis();
      } else {
        int lastCharacterIndex = axisName.Length - 1;
        char lastCharacter = axisName[lastCharacterIndex];
        if(lastCharacter == '-') {
          return new JoystickAxis(axisName.Substring(0, lastCharacter), true);
        } else if(lastCharacter == '+') {
          return new JoystickAxis(axisName.Substring(0, lastCharacter), false);
        } else {
          Debug.LogWarning(
            "Joystick axis '" + axisName + "' does not specify whether to use " +
            "the negative or the positive side of the axis. Binding not performed."
          );
          return new JoystickAxis();
        }
      }
    }

    /// <summary>
    ///   Default joystick axis that will be bound to the negative side of the axis
    /// </summary>
    private JoystickAxis defaultNegativeAxis;
    /// <summary>
    ///   Default joystick axis that will be bound to the positive side of the axis
    /// </summary>
    private JoystickAxis defaultPositiveAxis;

  }

} // namespace Framework.Input.States