using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using zero.Core.Entities;
using zero.Core.Extensions;
using zero.Core.Utils;

namespace zero.Core.Blueprints
{
  /// <summary>
  /// 
  /// </summary>
  public class Blueprint<T> : Blueprint where T : ZeroEntity, new()
  {
    public List<BlueprintField<T>> UnlockedFields { get; private set; } = new();

    protected static string[] DefaultFields { get; set; } = new[] { "name", "alias", "key", "sort", "isActive", "hash", "languageId", "createdById", "createdDate", "lastModifiedById", "lastModifiedDate", "blueprint" };


    public Blueprint() : base(typeof(T))
    {
      //Sync(x => x.Name);
      //Sync(x => x.Alias);
      //Sync(x => x.Sort);
      //Sync(x => x.IsActive);
      //Sync(x => x.LanguageId);
      //Sync(x => x.Key);
    }


    /// <summary>
    /// Merges blueprint data into a model based on the configuration
    /// </summary>
    public virtual T Apply(T blueprint, T model)
    {
      // reset blueprint options for model in case no blueprint was found
      if (blueprint == null || model.Blueprint == null)
      {
        model.Blueprint = null;
        return model;
      }

      // copy all properties which are synced from the blueprint to the model
      ApplyDefaults(blueprint, model);
      ObjectCloner.CopyProperties(blueprint, model, DefaultFields.Union(model.Blueprint.Desync).ToArray());

      return model;
    }


    /// <inheritdoc />
    public override ZeroEntity Apply(ZeroEntity blueprint, ZeroEntity model) => Apply(blueprint as T, model as T);


    /// <summary>
    /// Update default entity data
    /// </summary>
    protected virtual void ApplyDefaults(T blueprint, T model)
    {
      if (!model.Blueprint.Desync.Contains(nameof(ZeroEntity.Name), StringComparer))
      {
        model.Name = blueprint.Name;
        model.Alias = blueprint.Alias;
      }
      if (!model.Blueprint.Desync.Contains(nameof(ZeroEntity.Key), StringComparer))
      {
        model.Key = blueprint.Key;
      }
      if (!model.Blueprint.Desync.Contains(nameof(ZeroEntity.Sort), StringComparer))
      {
        model.Sort = blueprint.Sort;
      }
      if (!model.Blueprint.Desync.Contains(nameof(ZeroEntity.IsActive), StringComparer))
      {
        model.IsActive = blueprint.IsActive;
      }

      // these values can't be overridden
      model.Hash = blueprint.Hash;
      model.LanguageId = blueprint.LanguageId;
      model.CreatedById = blueprint.CreatedById;
      model.CreatedDate = blueprint.CreatedDate;
      model.LastModifiedById = blueprint.LastModifiedById;
      model.LastModifiedDate = blueprint.LastModifiedDate;
    }


    /// <summary>
    /// Lock a field so it always get synchronized no and cannot be changed
    /// </summary>
    public void LockAll()
    {
      UnlockedFields = new();
    }


    /// <summary>
    /// Lock a field so it always get synchronized no and cannot be changed
    /// </summary>
    public void Lock(Expression<Func<T, object>> selector)
    {
      RemoveField(selector);
    }


    public void Unlock(Expression<Func<T, object>> selector)
    {
      AddField(selector);
    }


    public void UnlockDefaults()
    {
      AddField(x => x.Name);
      AddField(x => x.Alias);
      AddField(x => x.Sort);
      AddField(x => x.Key);
      AddField(x => x.IsActive);
    }


    /// <inheritdoc />
    public override IEnumerable<string> GetUnlockedFieldNames()
    {
      foreach (BlueprintField<T> field in UnlockedFields)
      {
        yield return field.FieldName.ToCamelCaseId();
      }
    }


    /// <summary>
    /// Get existing field or create a new one
    /// </summary>
    protected BlueprintField<T> AddField(Expression<Func<T, object>> selector)
    {
      BlueprintField<T> tempField = new(selector);
      BlueprintField<T> storedField = UnlockedFields.FirstOrDefault(x => x.FieldName.Equals(tempField.FieldName, StringComparison.InvariantCultureIgnoreCase));

      if (storedField != null)
      {
        return storedField;
      }

      UnlockedFields.Add(tempField);
      return tempField;
    }


    /// <summary>
    /// Removes a field
    /// </summary>
    protected void RemoveField(Expression<Func<T, object>> selector)
    {
      BlueprintField<T> tempField = new(selector);

      if (tempField != null)
      {
        UnlockedFields.RemoveAll(x => x.FieldName.Equals(tempField.FieldName, StringComparison.InvariantCultureIgnoreCase));
      }
    }
  }


  /// <summary>
  /// 
  /// </summary>
  public abstract class Blueprint
  {
    /// <summary>
    /// Type of the associated entity
    /// </summary>
    public Type ContentType { get; private set; }

    public string Alias { get; private set; }

    /// <summary>
    /// String comparer for property name comparison
    /// </summary>
    protected readonly StringComparer StringComparer = StringComparer.InvariantCultureIgnoreCase;


    public Blueprint(Type type)
    {
      ContentType = type;
      Alias = type.Name.ToCamelCaseId();
    }

    /// <summary>
    /// Merges blueprint data into a model based on the configuration
    /// </summary>
    public abstract ZeroEntity Apply(ZeroEntity blueprint, ZeroEntity model);

    /// <summary>
    /// Get all fields which have been unlocked
    /// </summary>
    public abstract IEnumerable<string> GetUnlockedFieldNames();
  }


  public class DefaultBlueprint<T> : Blueprint<T> where T : ZeroEntity, new()
  {
    public DefaultBlueprint(Action<Blueprint<T>> expression = null) : base()
    {
      expression?.Invoke(this);
    }
  }
}