using System;

using UnityEngine;

namespace Framework.Services {
  
  /// <summary>Selects a default binding for a dependency-injected parameter</summary>
  [
    AttributeUsage(
      AttributeTargets.Parameter | AttributeTargets.Interface,
      Inherited = false,
      AllowMultiple = false
    )
  ]
  public class DefaultBindingAttribute : Attribute {

    /// <summary>Initializes a new default binding attribute</summary>
    /// <param named="serviceImplementationType">
    ///   Type that provides the implementation for the service
    /// </param>
    public DefaultBindingAttribute(Type serviceImplementationType) {
      this.serviceImplementationType = serviceImplementationType;
    }

    /// <summary>Initializes a new default binding attribute</summary>
    /// <param named="serviceImplementationTypeName">
    ///   Name of the type that provides the implementation for the service
    /// </param>
    public DefaultBindingAttribute(string serviceImplementationTypeName) {
      this.serviceImplementationTypeName = serviceImplementationTypeName;
    }
    
    /// <summary>Type that is providing the implementation for the service parameter</summary>
    public Type ServiceImplementationType {
      get {
        if(this.serviceImplementationType == null) {
          this.serviceImplementationType = Type.GetType(this.serviceImplementationTypeName);
        }
        
        return this.serviceImplementationType;
      }
    }
    
    /// <summary>Type that is providing the implementation for the service parameter</summary>
    private Type serviceImplementationType;
    /// <summary>Name of the type that is providing the service implementation</summary>
    private string serviceImplementationTypeName; 

  }

} // namespace Framework.Services