move 'WireMock.Net.OpenApiParser.Preview' to ''src-preview' folder

src-preview/WireMock.Net.OpenApiParser.Preview/Extensions/OpenApiSchemaExtensions.cs

@@ -0,0 +1,85 @@
+// Copyright © WireMock.Net
+
+using System.Linq;
+using System.Text.Json;
+using Microsoft.OpenApi.Any;
+using Microsoft.OpenApi.Models;
+using Microsoft.OpenApi.Models.Interfaces;
+using WireMock.Net.OpenApiParser.Types;
+
+namespace WireMock.Net.OpenApiParser.Extensions;
+
+internal static class OpenApiSchemaExtensions
+{
+    public static bool TryGetXNullable(this IOpenApiSchema schema, out bool value)
+    {
+        value = false;
+
+        if (schema.Extensions != null && schema.Extensions.TryGetValue(OpenApiConstants.NullableExtension, out var nullExtRawValue) && nullExtRawValue is OpenApiAny { Node: { } jsonNode })
+        {
+            value = jsonNode.GetValueKind() == JsonValueKind.True;
+            return true;
+        }
+
+        return false;
+    }
+
+    public static JsonSchemaType? GetSchemaType(this IOpenApiSchema? schema, out bool isNullable)
+    {
+        isNullable = false;
+
+        if (schema == null)
+        {
+            return null;
+        }
+
+        if (schema.Type == null)
+        {
+            if (schema.AllOf?.Any() == true || schema.AnyOf?.Any() == true)
+            {
+                return JsonSchemaType.Object;
+            }
+        }
+
+        isNullable = (schema.Type | JsonSchemaType.Null) == JsonSchemaType.Null || (schema.TryGetXNullable(out var xNullable) && xNullable);
+
+        // Removes the Null flag from the schema.Type, ensuring the returned value represents a non-nullable type.
+        return schema.Type & ~JsonSchemaType.Null;
+    }
+
+    public static SchemaFormat GetSchemaFormat(this IOpenApiSchema? schema)
+    {
+        switch (schema?.Format)
+        {
+            case "float":
+                return SchemaFormat.Float;
+
+            case "double":
+                return SchemaFormat.Double;
+
+            case "int32":
+                return SchemaFormat.Int32;
+
+            case "int64":
+                return SchemaFormat.Int64;
+
+            case "date":
+                return SchemaFormat.Date;
+
+            case "date-time":
+                return SchemaFormat.DateTime;
+
+            case "password":
+                return SchemaFormat.Password;
+
+            case "byte":
+                return SchemaFormat.Byte;
+
+            case "binary":
+                return SchemaFormat.Binary;
+
+            default:
+                return SchemaFormat.Undefined;
+        }
+    }
+}