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using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Text.Json;
using System.Xml;
using NUnit.Framework;
using Opc.Ua.Core.TestFramework;
using Opc.Ua.Tests;
using ComplexStructure = Opc.Ua.Encoders.Structure;

namespace Opc.Ua.Client.ComplexTypes.Tests
{
    /// <summary>
    /// Encoder/decoder tests for default complex types.
    /// Mirrors ComplexTypesEncoderTests from Opc.Ua.Client.ComplexTypes.Tests.
    /// </summary>
    [TestFixture]
    [Category("DefaultComplexTypes")]
    [Category("Encoder")]
    [SetCulture("en-us")]
    [SetUICulture("en-us")]
    [Parallelizable]
    public class DefaultComplexTypesEncoderTests : DefaultComplexTypesCommon
    {
        public IServiceMessageContext EncoderContext;
        public new ITelemetryContext Telemetry;
        public Dictionary<StructureType, (ExpandedNodeId, IEncodeableType)> TypeDictionary;

        [OneTimeSetUp]
        protected new void OneTimeSetUp()
        {
            Telemetry = NUnitTelemetryContext.Create();
            EncoderContext = ServiceMessageContext.Create(Telemetry);
            EncoderContext.NamespaceUris.Append("urn:This:is:my:test:encoder");
            EncoderContext.NamespaceUris.Append("urn:This:is:another:namespace");
            EncoderContext.NamespaceUris.Append(Namespaces.OpcUaEncoderTests);
            TypeDictionary = [];
            CreateComplexTypes(EncoderContext, TypeDictionary, string.Empty);
        }

        [OneTimeTearDown]
        protected new void OneTimeTearDown()
        {
        }

        [SetUp]
        protected new void SetUp()
        {
        }

        [TearDown]
        protected new void TearDown()
        {
        }

        /// <summary>
        /// Binary-decoded enum fields retain known symbols and unknown numeric values.
        /// </summary>
        [TestCase(ValueRanks.Scalar, 1, true)]
        [TestCase(ValueRanks.OneDimension, 1, true)]
        [TestCase(ValueRanks.TwoDimensions, 1, true)]
        [TestCase(ValueRanks.Scalar, 99, true)]
        [TestCase(ValueRanks.OneDimension, 99, true)]
        [TestCase(ValueRanks.TwoDimensions, 99, true)]
        [TestCase(ValueRanks.Scalar, 1, false)]
        [TestCase(ValueRanks.OneDimension, 1, false)]
        [TestCase(ValueRanks.TwoDimensions, 1, false)]
        public void BinaryStructureRoundTripPreservesEnumerationSymbols(int valueRank, int numericValue, bool registerType)
        {
            ServiceMessageContext context = ServiceMessageContext.Create(Telemetry);
            const string namespaceUri = "urn:enum-symbol-regression";
            ushort namespaceIndex = context.NamespaceUris.GetIndexOrAppend(namespaceUri);
            var enumId = new NodeId(1, namespaceIndex);
            var enumType = new Opc.Ua.Encoders.Enumeration(
                new XmlQualifiedName("State", namespaceUri),
                new EnumDefinition
                {
                    Fields = [new EnumField { Name = "On", Value = 1 }]
                });
            if (registerType)
            {
                context.Factory.Builder
                    .AddEnumeratedType(NodeId.ToExpandedNodeId(enumId, context.NamespaceUris), enumType)
                    .Commit();
            }
            var original = new ComplexStructure(
                new XmlQualifiedName("Machine", namespaceUri),
                new ExpandedNodeId(2, namespaceUri),
                new ExpandedNodeId(3, namespaceUri),
                new ExpandedNodeId(4, namespaceUri),
                new StructureDefinition
                {
                    StructureType = StructureType.Structure,
                    BaseDataType = DataTypeIds.Structure,
                    Fields = [new StructureField { Name = "State", DataType = enumId, ValueRank = valueRank }]
                },
                new Dictionary<string, BuiltInType> { ["State"] = BuiltInType.Enumeration });
            var enumValue = new EnumValue(numericValue, enumType);
            original["State"] = valueRank switch
            {
                ValueRanks.Scalar => Variant.From(enumValue),
                ValueRanks.OneDimension => Variant.From(new EnumValue[] { enumValue }.ToArrayOf()),
                _ => Variant.From(MatrixOf.From<EnumValue>(new EnumValue[,] { { enumValue } }))
            };
            using var encoder = new BinaryEncoder(context);
            original.Encode(encoder);
            using var decoder = new BinaryDecoder(encoder.CloseAndReturnBuffer()!, context);
            var decoded = (ComplexStructure)original.CreateInstance();
            decoded.Decode(decoder);
            ArrayOf<EnumValue> actual = valueRank switch
            {
                ValueRanks.Scalar => new EnumValue[] { decoded["State"].GetEnumeration() }.ToArrayOf(),
                ValueRanks.OneDimension => decoded["State"].GetEnumerationArray(),
                _ => decoded["State"].GetEnumerationMatrix().ToArrayOf()
            };
            Assert.That(actual.Count, Is.EqualTo(1));
            Assert.That(actual[0].Value, Is.EqualTo(numericValue));
            Assert.That(actual[0].Symbol, Is.EqualTo(registerType && numericValue == 1 ? "On" : null));

            using var jsonEncoder = new JsonEncoder(context, JsonEncoderOptions.RawData);
            jsonEncoder.WriteEncodeable("Machine", decoded, ExpandedNodeId.Null);
            using JsonDocument json = JsonDocument.Parse(jsonEncoder.CloseAndReturnText());
            JsonElement state = json.RootElement.GetProperty("Machine").GetProperty("State");
            string expected = registerType && numericValue == 1 ? "On_1" : numericValue.ToString(CultureInfo.InvariantCulture);
            if (valueRank == ValueRanks.Scalar)
            {
                Assert.That(state.GetString(), Is.EqualTo(expected));
            }
            else
            {
                Assert.That(state.GetRawText(), Does.Contain($"\"{expected}\""));
            }
        }

        /// <summary>
        /// Enumeration metadata does not change null or empty array values during decoding.
        /// </summary>
        [Test]
        [Combinatorial]
        public void BinaryStructureRoundTripPreservesNullAndEmptyEnumerationArrays(
            [Values] bool isNull,
            [Values] bool registerType)
        {
            ServiceMessageContext context = ServiceMessageContext.Create(Telemetry);
            const string namespaceUri = "urn:enum-array-null-regression";
            ushort namespaceIndex = context.NamespaceUris.GetIndexOrAppend(namespaceUri);
            var enumId = new NodeId(1, namespaceIndex);
            if (registerType)
            {
                context.Factory.Builder.AddEnumeratedType(
                    NodeId.ToExpandedNodeId(enumId, context.NamespaceUris),
                    new Opc.Ua.Encoders.Enumeration(
                        new XmlQualifiedName("State", namespaceUri),
                        new EnumDefinition { Fields = [new EnumField { Name = "On", Value = 1 }] }))
                    .Commit();
            }
            var original = new ComplexStructure(
                new XmlQualifiedName("Machine", namespaceUri),
                new ExpandedNodeId(2, namespaceUri),
                new ExpandedNodeId(3, namespaceUri),
                new ExpandedNodeId(4, namespaceUri),
                new StructureDefinition
                {
                    StructureType = StructureType.Structure,
                    BaseDataType = DataTypeIds.Structure,
                    Fields = [new StructureField
                    {
                        Name = "State",
                        DataType = enumId,
                        ValueRank = ValueRanks.OneDimension
                    }]
                },
                new Dictionary<string, BuiltInType> { ["State"] = BuiltInType.Enumeration });
            original["State"] = Variant.From(isNull ? ArrayOf<EnumValue>.Null : ArrayOf<EnumValue>.Empty);

            using var encoder = new BinaryEncoder(context);
            original.Encode(encoder);
            byte[] encoded = encoder.CloseAndReturnBuffer()!;
            using var decoder = new BinaryDecoder(encoded!, context);
            var decoded = (ComplexStructure)original.CreateInstance();
            decoded.Decode(decoder);
            ArrayOf<EnumValue> actual = decoded["State"].GetEnumerationArray();
            Assert.That(actual.IsNull, Is.EqualTo(isNull));
            Assert.That(actual.Count, Is.Zero);

            using var roundTripEncoder = new BinaryEncoder(context);
            decoded.Encode(roundTripEncoder);
            Assert.That(roundTripEncoder.CloseAndReturnBuffer(), Is.EqualTo(encoded));
        }

        /// <summary>
        /// XML enum fields preserve missing values and recover metadata from integer representations.
        /// </summary>
        [Test]
        [Combinatorial]
        public void XmlStructurePreservesEnumerationValues(
            [Values(ValueRanks.Scalar, ValueRanks.OneDimension, ValueRanks.TwoDimensions)] int valueRank,
            [Values] bool useParser,
            [Values("Missing", "Null", "Value", "Unknown")] string valueKind)
        {
            ServiceMessageContext context = ServiceMessageContext.Create(Telemetry);
            const string namespaceUri = "urn:xml-enum-regression";
            ushort namespaceIndex = context.NamespaceUris.GetIndexOrAppend(namespaceUri);
            var enumId = new NodeId(1, namespaceIndex);
            var enumType = new Opc.Ua.Encoders.Enumeration(
                new XmlQualifiedName("State", namespaceUri),
                new EnumDefinition { Fields = [new EnumField { Name = "On", Value = 1 }] });
            var original = new ComplexStructure(
                new XmlQualifiedName("Machine", namespaceUri),
                new ExpandedNodeId(2, namespaceUri),
                new ExpandedNodeId(3, namespaceUri),
                new ExpandedNodeId(4, namespaceUri),
                new StructureDefinition
                {
                    StructureType = StructureType.Structure,
                    BaseDataType = DataTypeIds.Structure,
                    Fields = [new StructureField { Name = "State", DataType = enumId, ValueRank = valueRank }]
                },
                new Dictionary<string, BuiltInType> { ["State"] = BuiltInType.Enumeration });
            context.Factory.Builder
                .AddEnumeratedType(NodeId.ToExpandedNodeId(enumId, context.NamespaceUris), enumType)
                .AddEncodeableType(original)
                .Commit();
            int numericValue = valueKind == "Unknown" ? 99 : 1;
            string xml;
            if (valueKind is "Missing" or "Null")
            {
                string field = valueKind == "Missing" ? "<Unrelated />"
                    : $"<State><Null xmlns=\"{Opc.Ua.Namespaces.OpcUaXsd}\" /></State>";
                xml = $"<Machine xmlns=\"{namespaceUri}\">{field}</Machine>";
            }
            else if (valueKind is "NullArray" or "EmptyArray")
            {
                string nil = valueKind == "NullArray" ? " xsi:nil=\"true\"" : string.Empty;
                xml = $"<Machine xmlns=\"{namespaceUri}\" xmlns:xsi=\"{Opc.Ua.Namespaces.XmlSchemaInstance}\">" +
                    $"<State><ListOfInt32 xmlns=\"{Opc.Ua.Namespaces.OpcUaXsd}\"{nil} /></State></Machine>";
            }
            else
            {
                var enumValue = new EnumValue(numericValue, enumType);
                original["State"] = valueRank switch
                {
                    ValueRanks.Scalar => Variant.From(enumValue),
                    ValueRanks.OneDimension => Variant.From(new EnumValue[] { enumValue }.ToArrayOf()),
                    _ => Variant.From(MatrixOf.From<EnumValue>(new EnumValue[,] { { enumValue } }))
                };
                using var encoder = new XmlEncoder(context);
                encoder.PushNamespace(namespaceUri);
                encoder.WriteEncodeable("Machine", original, original.TypeId);
                xml = encoder.CloseAndReturnText()!;
            }
            using var reader = XmlReader.Create(new StringReader(xml!));
            using IDecoder decoder = useParser ? new XmlParser(xml, context) : new XmlDecoder(reader, context);
            decoder.PushNamespace(namespaceUri);
            ComplexStructure decoded = decoder.ReadEncodeable<ComplexStructure>("Machine", original.TypeId);
            if (valueKind is "NullArray" or "EmptyArray")
            {
                Assert.That(decoded["State"].GetInt32Array().IsNull, Is.EqualTo(valueKind == "NullArray"));
                Assert.That(decoded["State"].GetInt32Array().Count, Is.Zero);
                return;
            }
            if (valueKind is "Missing" or "Null")
            {
                Assert.That(decoded["State"].IsNull, Is.True);
                return;
            }
            ArrayOf<EnumValue> values = valueRank switch
            {
                ValueRanks.Scalar => new EnumValue[] { decoded["State"].GetEnumeration() }.ToArrayOf(),
                ValueRanks.OneDimension => decoded["State"].GetEnumerationArray(),
                _ => decoded["State"].GetEnumerationMatrix().ToArrayOf()
            };
            Assert.That(values.Count, Is.EqualTo(1));
            Assert.That(values[0].Value, Is.EqualTo(numericValue));
            Assert.That(values[0].Symbol, Is.EqualTo(valueKind == "Value" ? "On" : null));
        }

        /// <summary>
        /// XML integer-array representations retain null and empty states when enum metadata is restored.
        /// </summary>
        [Test]
        [Combinatorial]
        public void XmlEnumerationArraysPreserveNullAndEmpty([Values] bool useParser, [Values] bool isNull)
        {
            XmlStructurePreservesEnumerationValues(
                ValueRanks.OneDimension, useParser, isNull ? "NullArray" : "EmptyArray");
        }

        /// <summary>
        /// Verify encode and decode of a structured type.
        /// </summary>
        [Theory]
        [Category("DefaultComplexTypes")]
        public void ReEncodeComplexType(
            [ValueSource(
                nameof(EncodingTypesJsonBinaryXmlAndJsonCompact))] EncodingTypeGroup encoderTypeGroup,
            MemoryStreamType memoryStreamType,
            StructureType structureType)
        {
            EncodingType encoderType = encoderTypeGroup.EncoderType;
            JsonEncodingType jsonEncodingType = encoderTypeGroup.JsonEncodingType;
            bool useXmlParser = encoderTypeGroup.UseXmlParser;
            (ExpandedNodeId nodeId, IEncodeableType encodeableType) = TypeDictionary[structureType];
            IEncodeable instance = encodeableType.CreateInstance();
            var structure = instance as ComplexStructure;
            Assert.That(structure, Is.Not.Null);
            FillStructWithValues(structure, true, NameSpaceUris);
            EncodeDecodeComplexType(
                EncoderContext,
                memoryStreamType,
                encoderType,
                jsonEncodingType,
                useXmlParser,
                structureType,
                nodeId,
                instance);
        }

        /// <summary>
        /// Verify encode and decode of a Structure type with optional fields.
        /// </summary>
        [Theory]
        [Category("DefaultComplexTypes")]
        public void ReEncodeStructureWithOptionalFieldsComplexType(
            [ValueSource(
                nameof(EncodingTypesJsonBinaryXmlAndJsonCompact))] EncodingTypeGroup encoderTypeGroup,
            MemoryStreamType memoryStreamType,
            StructureFieldParameter structureFieldParameter)
        {
            EncodingType encoderType = encoderTypeGroup.EncoderType;
            JsonEncodingType jsonEncodingType = encoderTypeGroup.JsonEncodingType;
            bool useXmlParser = encoderTypeGroup.UseXmlParser;
            (ExpandedNodeId nodeId, IEncodeableType encodeableType) =
                TypeDictionary[StructureType.StructureWithOptionalFields];
            IEncodeable instance = encodeableType.CreateInstance();
            var structure = instance as ComplexStructure;
            Assert.That(structure, Is.Not.Null);

            TestOutput.WriteLine(
                $"Optional Field: {structureFieldParameter.BuiltInType} is the only value.");
            structure[structureFieldParameter.Name] =
                DataGenerator.GetRandomVariant(structureFieldParameter.BuiltInType, false);
            EncodeDecodeComplexType(
                EncoderContext,
                memoryStreamType,
                encoderType,
                jsonEncodingType,
                useXmlParser,
                StructureType.StructureWithOptionalFields,
                nodeId,
                instance);

            TestOutput.WriteLine(
                $"Optional Field: {structureFieldParameter.BuiltInType} is null.");
            structure[structureFieldParameter.Name] = default;
            EncodeDecodeComplexType(
                EncoderContext,
                memoryStreamType,
                encoderType,
                jsonEncodingType,
                useXmlParser,
                StructureType.StructureWithOptionalFields,
                nodeId,
                instance);

            TestOutput.WriteLine(
                $"Optional Field: {structureFieldParameter.BuiltInType} is null, all other fields have random values.");
            FillStructWithValues(structure, true, NameSpaceUris);
            structure[structureFieldParameter.Name] = default;
            EncodeDecodeComplexType(
                EncoderContext,
                memoryStreamType,
                encoderType,
                jsonEncodingType,
                useXmlParser,
                StructureType.StructureWithOptionalFields,
                nodeId,
                instance);

            TestOutput.WriteLine(
                $"Optional Field: {structureFieldParameter.BuiltInType} has random value.");
            structure[structureFieldParameter.Name] =
                DataGenerator.GetRandomVariant(structureFieldParameter.BuiltInType, false);
            EncodeDecodeComplexType(
                EncoderContext,
                memoryStreamType,
                encoderType,
                jsonEncodingType,
                useXmlParser,
                StructureType.StructureWithOptionalFields,
                nodeId,
                instance);
        }

        /// <summary>
        /// Verify encode and decode of a Union type.
        /// </summary>
        [Theory]
        [Category("DefaultComplexTypes")]
        public void ReEncodeUnionComplexType(
            [ValueSource(
                nameof(EncodingTypesJsonBinaryXmlAndJsonCompact))] EncodingTypeGroup encoderTypeGroup,
            MemoryStreamType memoryStreamType,
            StructureFieldParameter structureFieldParameter)
        {
            EncodingType encoderType = encoderTypeGroup.EncoderType;
            JsonEncodingType jsonEncodingType = encoderTypeGroup.JsonEncodingType;
            bool useXmlParser = encoderTypeGroup.UseXmlParser;
            (ExpandedNodeId nodeId, IEncodeableType encodeableType) =
                TypeDictionary[StructureType.Union];
            IEncodeable instance = encodeableType.CreateInstance();
            var structure = instance as ComplexStructure;
            Assert.That(structure, Is.Not.Null);

            TestOutput.WriteLine(
                $"Union Field: {structureFieldParameter.BuiltInType} is random.");
            structure[structureFieldParameter.Name] =
                DataGenerator.GetRandomVariant(structureFieldParameter.BuiltInType, false);
            EncodeDecodeComplexType(
                EncoderContext,
                memoryStreamType,
                encoderType,
                jsonEncodingType,
                useXmlParser,
                StructureType.Union,
                nodeId,
                instance);

            TestOutput.WriteLine(
                $"Union Field: {structureFieldParameter.BuiltInType} is null.");
            structure[structureFieldParameter.Name] = default;
            EncodeDecodeComplexType(
                EncoderContext,
                memoryStreamType,
                encoderType,
                jsonEncodingType,
                useXmlParser,
                StructureType.Union,
                nodeId,
                instance);
        }
    }
}