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using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata;
using Microsoft.EntityFrameworkCore.Metadata.Builders;
using Microsoft.EntityFrameworkCore.Metadata.Conventions;
using Microsoft.EntityFrameworkCore.Metadata.Conventions.Infrastructure;
using MySql.EntityFrameworkCore.Extensions;
using MySql.EntityFrameworkCore.Metadata.Internal;

namespace MySql.EntityFrameworkCore.Metadata.Conventions
{
  /// <summary>
  ///     A convention that configures store value generation as <see cref="ValueGenerated.OnAdd"/> on properties that are
  ///     part of the primary key and not part of any foreign keys, are configured to have a database default value, or are 
  ///     configured to use a <see cref="SqlServerValueGenerationStrategy"/>.
  ///     It also configures properties as <see cref="ValueGenerated.OnAddOrUpdate"/> if they are configured as computed columns.
  /// </summary>
  internal class MySQLValueGenerationConvention : RelationalValueGenerationConvention
  {
    /// <summary>
    /// Creates a new instance of <see cref="MySQLValueGenerationConvention" />.
    /// </summary>
    /// <param name="dependencies"> Parameter object containing dependencies for this convention. </param>
    /// <param name="relationalDependencies">  Parameter object containing relational dependencies for this convention. </param>
    public MySQLValueGenerationConvention(
      [NotNull] ProviderConventionSetBuilderDependencies dependencies,
      [NotNull] RelationalConventionSetBuilderDependencies relationalDependencies)
      : base(dependencies, relationalDependencies)
    {
    }

    /// <summary>
    /// Called after an annotation is changed on a property.
    /// </summary>
    /// <param name="propertyBuilder"> The builder for the property. </param>
    /// <param name="name"> The annotation name. </param>
    /// <param name="annotation"> The new annotation. </param>
    /// <param name="oldAnnotation"> The old annotation.  </param>
    /// <param name="context"> Additional information associated with convention execution. </param>
    public override void ProcessPropertyAnnotationChanged(
        IConventionPropertyBuilder propertyBuilder,
        string name,
        IConventionAnnotation? annotation,
        IConventionAnnotation? oldAnnotation,
        IConventionContext<IConventionAnnotation> context)
    {
      if (name == MySQLAnnotationNames.ValueGenerationStrategy)
      {
        propertyBuilder.ValueGenerated(GetValueGenerated(propertyBuilder.Metadata));
        return;
      }

      base.ProcessPropertyAnnotationChanged(propertyBuilder, name, annotation, oldAnnotation, context);
    }

    /// <summary>
    /// Indicates the store value generation strategy to set for the given property.
    /// </summary>
    /// <param name="property"> The property. </param>
    /// <returns> The store value generation strategy to set for the given property. </returns>
    protected override ValueGenerated? GetValueGenerated(IConventionProperty property)
    {
      var tableName = property.DeclaringEntityType.GetTableName();
      if (tableName == null)
      {
        return null;
      }

      return GetValueGenerated(
        property, StoreObjectIdentifier.Table(tableName, property.DeclaringEntityType.GetSchema()));
    }

    /// <summary>
    /// Indicates the store value generation strategy to set for the given property.
    /// </summary>
    /// <param name="property"> The property. </param>
    /// <returns> The store value generation strategy to set for the given property. </returns>
    public static new ValueGenerated? GetValueGenerated([NotNull] IProperty property)
    {
      var valueGenerated = RelationalValueGenerationConvention.GetValueGenerated(property);
      if (valueGenerated != null)
      {
        return valueGenerated;
      }

      var valueGenerationStrategy = property.GetValueGenerationStrategy();
      if (valueGenerationStrategy.HasValue)
      {
        switch (valueGenerationStrategy.Value)
        {
          case MySQLValueGenerationStrategy.IdentityColumn:
            return ValueGenerated.OnAdd;
          case MySQLValueGenerationStrategy.ComputedColumn:
            return ValueGenerated.OnAddOrUpdate;
        }
      }

      return null;
    }
  }
}