using System;
using System.Collections.Generic;
using System.Linq;
using Unosquare.Swan.Exceptions;

namespace Unosquare.Swan.Components {
  /// <summary>
  /// Registration options for "fluent" API.
  /// </summary>
  public sealed class RegisterOptions {
    private readonly TypesConcurrentDictionary _registeredTypes;
    private readonly DependencyContainer.TypeRegistration _registration;

    /// <summary>
    /// Initializes a new instance of the <see cref="RegisterOptions" /> class.
    /// </summary>
    /// <param name="registeredTypes">The registered types.</param>
    /// <param name="registration">The registration.</param>
    public RegisterOptions(TypesConcurrentDictionary registeredTypes, DependencyContainer.TypeRegistration registration) {
      this._registeredTypes = registeredTypes;
      this._registration = registration;
    }

    /// <summary>
    /// Make registration a singleton (single instance) if possible.
    /// </summary>
    /// <returns>A registration options  for fluent API.</returns>
    /// <exception cref="DependencyContainerRegistrationException">Generic constraint registration exception.</exception>
    public RegisterOptions AsSingleton() {
      ObjectFactoryBase currentFactory = this._registeredTypes.GetCurrentFactory(this._registration);

      if(currentFactory == null) {
        throw new DependencyContainerRegistrationException(this._registration.Type, "singleton");
      }

      return this._registeredTypes.AddUpdateRegistration(this._registration, currentFactory.SingletonVariant);
    }

    /// <summary>
    /// Make registration multi-instance if possible.
    /// </summary>
    /// <returns>A registration options  for fluent API.</returns>
    /// <exception cref="DependencyContainerRegistrationException">Generic constraint registration exception.</exception>
    public RegisterOptions AsMultiInstance() {
      ObjectFactoryBase currentFactory = this._registeredTypes.GetCurrentFactory(this._registration);

      if(currentFactory == null) {
        throw new DependencyContainerRegistrationException(this._registration.Type, "multi-instance");
      }

      return this._registeredTypes.AddUpdateRegistration(this._registration, currentFactory.MultiInstanceVariant);
    }

    /// <summary>
    /// Make registration hold a weak reference if possible.
    /// </summary>
    /// <returns>A registration options  for fluent API.</returns>
    /// <exception cref="DependencyContainerRegistrationException">Generic constraint registration exception.</exception>
    public RegisterOptions WithWeakReference() {
      ObjectFactoryBase currentFactory = this._registeredTypes.GetCurrentFactory(this._registration);

      if(currentFactory == null) {
        throw new DependencyContainerRegistrationException(this._registration.Type, "weak reference");
      }

      return this._registeredTypes.AddUpdateRegistration(this._registration, currentFactory.WeakReferenceVariant);
    }

    /// <summary>
    /// Make registration hold a strong reference if possible.
    /// </summary>
    /// <returns>A registration options  for fluent API.</returns>
    /// <exception cref="DependencyContainerRegistrationException">Generic constraint registration exception.</exception>
    public RegisterOptions WithStrongReference() {
      ObjectFactoryBase currentFactory = this._registeredTypes.GetCurrentFactory(this._registration);

      if(currentFactory == null) {
        throw new DependencyContainerRegistrationException(this._registration.Type, "strong reference");
      }

      return this._registeredTypes.AddUpdateRegistration(this._registration, currentFactory.StrongReferenceVariant);
    }
  }

  /// <summary>
  /// Registration options for "fluent" API when registering multiple implementations.
  /// </summary>
  public sealed class MultiRegisterOptions {
    private IEnumerable<RegisterOptions> _registerOptions;

    /// <summary>
    /// Initializes a new instance of the <see cref="MultiRegisterOptions"/> class.
    /// </summary>
    /// <param name="registerOptions">The register options.</param>
    public MultiRegisterOptions(IEnumerable<RegisterOptions> registerOptions) => this._registerOptions = registerOptions;

    /// <summary>
    /// Make registration a singleton (single instance) if possible.
    /// </summary>
    /// <returns>A registration multi-instance for fluent API.</returns>
    /// <exception cref="DependencyContainerRegistrationException">Generic Constraint Registration Exception.</exception>
    public MultiRegisterOptions AsSingleton() {
      this._registerOptions = this.ExecuteOnAllRegisterOptions(ro => ro.AsSingleton());
      return this;
    }

    /// <summary>
    /// Make registration multi-instance if possible.
    /// </summary>
    /// <returns>A registration multi-instance for fluent API.</returns>
    /// <exception cref="DependencyContainerRegistrationException">Generic Constraint Registration Exception.</exception>
    public MultiRegisterOptions AsMultiInstance() {
      this._registerOptions = this.ExecuteOnAllRegisterOptions(ro => ro.AsMultiInstance());
      return this;
    }

    private IEnumerable<RegisterOptions> ExecuteOnAllRegisterOptions(
        Func<RegisterOptions, RegisterOptions> action) => this._registerOptions.Select(action).ToList();
  }
}