/*************************************************************************
 * ModernUO                                                              *
 * Copyright 2019-2021 - ModernUO Development Team                       *
 * Email: hi@modernuo.com                                                *
 * File: SerializableEntityGeneration.Class.cs                           *
 *                                                                       *
 * This program is free software: you can redistribute it and/or modify  *
 * it under the terms of the GNU General Public License as published by  *
 * the Free Software Foundation, either version 3 of the License, or     *
 * (at your option) any later version.                                   *
 *                                                                       *
 * You should have received a copy of the GNU General Public License     *
 * along with this program.  If not, see <http://www.gnu.org/licenses/>. *
 *************************************************************************/

using System;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.IO;
using System.Linq;
using System.Text;
using System.Text.Json;
using Microsoft.CodeAnalysis;
using SerializableMigration;

namespace SerializationGenerator
{
    public static partial class SerializableEntityGeneration
    {
        public static string GenerateSerializationPartialClass(
            this GeneratorExecutionContext context,
            INamedTypeSymbol classSymbol,
            AttributeData serializableAttr,
            bool embedded,
            ImmutableArray<ISymbol> fieldsAndProperties,
            JsonSerializerOptions jsonSerializerOptions,
            ImmutableArray<INamedTypeSymbol> serializableTypes,
            ImmutableArray<INamedTypeSymbol> embeddedSerializableTypes
        )
        {
            var version = (int)serializableAttr.ConstructorArguments[0].Value!;

            var migrations = context.GetMigrationsByAnalyzerConfig(
                classSymbol,
                version,
                jsonSerializerOptions
            );

            return context.Compilation.GenerateSerializationPartialClass(
                classSymbol,
                serializableAttr,
                null, // Do not generate schema
                embedded,
                null,
                migrations.ToImmutableArray(),
                fieldsAndProperties,
                serializableTypes,
                embeddedSerializableTypes
            );
        }

        public static string GenerateSerializationPartialClass(
            this Compilation compilation,
            INamedTypeSymbol classSymbol,
            AttributeData serializableAttr,
            string? migrationPath,
            bool embedded,
            JsonSerializerOptions? jsonSerializerOptions,
            ImmutableArray<ISymbol> fieldsAndProperties,
            ImmutableArray<INamedTypeSymbol> serializableTypes,
            ImmutableArray<INamedTypeSymbol> embeddedSerializableTypes
        )
        {
            var version = (int)serializableAttr.ConstructorArguments[0].Value!;

            var migrations = SerializableMigrationSchema.GetMigrations(
                classSymbol,
                version,
                migrationPath,
                jsonSerializerOptions
            );

            return compilation.GenerateSerializationPartialClass(
                classSymbol,
                serializableAttr,
                migrationPath,
                embedded,
                jsonSerializerOptions,
                migrations.ToImmutableArray(),
                fieldsAndProperties,
                serializableTypes,
                embeddedSerializableTypes
            );
        }

        public static string GenerateSerializationPartialClass(
            this Compilation compilation,
            INamedTypeSymbol classSymbol,
            AttributeData serializableAttr,
            string? migrationPath,
            bool embedded,
            JsonSerializerOptions? jsonSerializerOptions,
            ImmutableArray<SerializableMetadata> migrations,
            ImmutableArray<ISymbol> fieldsAndProperties,
            ImmutableArray<INamedTypeSymbol> serializableTypes,
            ImmutableArray<INamedTypeSymbol> embeddedSerializableTypes
        )
        {
            var serializableFieldAttribute =
                compilation.GetTypeByMetadataName(SymbolMetadata.SERIALIZABLE_FIELD_ATTRIBUTE);
            var serializableFieldAttrAttribute =
                compilation.GetTypeByMetadataName(SymbolMetadata.SERIALIZABLE_FIELD_ATTR_ATTRIBUTE);
            var serializableInterface =
                compilation.GetTypeByMetadataName(SymbolMetadata.SERIALIZABLE_INTERFACE);
            var parentSerializableAttribute =
                compilation.GetTypeByMetadataName(SymbolMetadata.SERIALIZABLE_PARENT_ATTRIBUTE);
            var serializableFieldSaveFlagAttribute =
                compilation.GetTypeByMetadataName(SymbolMetadata.SERIALIZABLE_FIELD_SAVE_FLAG_ATTRIBUTE);
            var serializableFieldDefaultAttribute =
                compilation.GetTypeByMetadataName(SymbolMetadata.SERIALIZABLE_FIELD_DEFAULT_ATTRIBUTE);

            // If we have a parent that is or derives from ISerializable, then we are in override
            var isOverride = classSymbol.BaseType.ContainsInterface(serializableInterface);

            if (!(embedded || isOverride || classSymbol.ContainsInterface(serializableInterface)))
            {
                return null;
            }

            var isRawSerializable = classSymbol.HasRawSerializableInterface(compilation, ImmutableArray<INamedTypeSymbol>.Empty);

            var version = (int)serializableAttr.ConstructorArguments[0].Value!;
            var encodedVersion = (bool)serializableAttr.ConstructorArguments[1].Value!;

            // Let's find out if we need to do serialization flags
            var serializableFieldSaveFlags = new SortedDictionary<int, SerializableFieldSaveFlagMethods>();
            foreach (var m in classSymbol.GetMembers().OfType<IMethodSymbol>())
            {
                var getSaveFlagAttribute = m.GetAttribute(serializableFieldSaveFlagAttribute);
                var getDefaultValueAttribute = m.GetAttribute(serializableFieldDefaultAttribute);

                if (getSaveFlagAttribute == null && getDefaultValueAttribute == null)
                {
                    continue;
                }

                var attrCtorArgs = getSaveFlagAttribute?.ConstructorArguments ?? getDefaultValueAttribute.ConstructorArguments;
                var order = (int)attrCtorArgs[0].Value!;

                serializableFieldSaveFlags.TryGetValue(order, out var saveFlagMethods);

                serializableFieldSaveFlags[order] = new SerializableFieldSaveFlagMethods
                {
                    DetermineFieldShouldSerialize = getSaveFlagAttribute != null ? m : saveFlagMethods?.DetermineFieldShouldSerialize,
                    GetFieldDefaultValue = getDefaultValueAttribute != null ? m : saveFlagMethods?.GetFieldDefaultValue
                };
            }

            var namespaceName = classSymbol.ContainingNamespace.ToDisplayString();
            var className = classSymbol.Name;

            StringBuilder source = new StringBuilder();

            source.AppendLine("#pragma warning disable\n");
            source.GenerateNamespaceStart(namespaceName);

            var interfaces = !embedded || isRawSerializable
                ? Array.Empty<ITypeSymbol>()
                : new ITypeSymbol[] { compilation.GetTypeByMetadataName(SymbolMetadata.RAW_SERIALIZABLE_INTERFACE) };

            var indent = "    ";

            source.RecursiveGenerateClassStart(classSymbol, interfaces.ToImmutableArray(), ref indent);
            indent += "    ";

            source.GenerateClassField(
                indent,
                Accessibility.Private,
                InstanceModifier.Const,
                "int",
                "_version",
                version.ToString()
            );
            source.AppendLine();

            var parentFieldOrProperty = embedded ? fieldsAndProperties.FirstOrDefault(
                fieldOrPropertySymbol => fieldOrPropertySymbol.GetAttributes()
                    .FirstOrDefault(
                        attr =>
                            SymbolEqualityComparer.Default.Equals(attr.AttributeClass, parentSerializableAttribute)
                    ) != null
            ) : null;

            var serializablePropertySet = new SortedSet<SerializableProperty>(new SerializablePropertyComparer());

            foreach (var fieldOrPropertySymbol in fieldsAndProperties)
            {
                var allAttributes = fieldOrPropertySymbol.GetAttributes();

                var serializableFieldAttr = allAttributes
                    .FirstOrDefault(
                        attr =>
                            SymbolEqualityComparer.Default.Equals(attr.AttributeClass, serializableFieldAttribute)
                    );

                if (serializableFieldAttr == null)
                {
                    continue;
                }

                foreach (var attr in allAttributes)
                {
                    if (!SymbolEqualityComparer.Default.Equals(attr.AttributeClass, serializableFieldAttrAttribute))
                    {
                        continue;
                    }

                    if (attr.AttributeClass == null)
                    {
                        continue;
                    }

                    var ctorArgs = attr.ConstructorArguments;
                    var attrTypeArg = ctorArgs[0];

                    if (attrTypeArg.Kind == TypedConstantKind.Primitive && attrTypeArg.Value is string attrStr)
                    {
                        source.AppendLine($"{indent}    {attrStr}");
                    }
                    else
                    {
                        var attrType = (ITypeSymbol)attrTypeArg.Value;
                        source.GenerateAttribute(attrType?.Name, ctorArgs[1].Values);
                    }
                }

                var attrCtorArgs = serializableFieldAttr.ConstructorArguments;

                var order = (int)attrCtorArgs[0].Value!;
                var getterAccessor = Helpers.GetAccessibility(attrCtorArgs[1].Value?.ToString());
                var setterAccessor = Helpers.GetAccessibility(attrCtorArgs[2].Value?.ToString());
                var virtualProperty = (bool)attrCtorArgs[3].Value!;

                if (fieldOrPropertySymbol is IFieldSymbol fieldSymbol)
                {
                    source.GenerateSerializableProperty(
                        compilation,
                        fieldSymbol,
                        getterAccessor,
                        setterAccessor,
                        virtualProperty,
                        parentFieldOrProperty
                    );
                    source.AppendLine();
                }

                serializableFieldSaveFlags.TryGetValue(order, out var serializableFieldSaveFlagMethods);

                var serializableProperty = SerializableMigrationRulesEngine.GenerateSerializableProperty(
                    compilation,
                    fieldOrPropertySymbol,
                    order,
                    allAttributes,
                    serializableTypes,
                    embeddedSerializableTypes,
                    classSymbol,
                    serializableFieldSaveFlagMethods
                );

                serializablePropertySet.Add(serializableProperty);
            }

            var serializableProperties = serializablePropertySet.ToImmutableArray();

            // If we are not inheriting ISerializable, then we need to define some stuff
            if (!(isOverride || embedded))
            {
                // long ISerializable.SavePosition { get; set; } = -1;
                source.GenerateAutoProperty(
                    Accessibility.NotApplicable,
                    "long",
                    "ISerializable.SavePosition",
                    Accessibility.NotApplicable,
                    Accessibility.NotApplicable,
                    indent,
                    defaultValue: "-1"
                );

                // BufferWriter ISerializable.SaveBuffer { get; set; }
                source.GenerateAutoProperty(
                    Accessibility.NotApplicable,
                    "BufferWriter",
                    "ISerializable.SaveBuffer",
                    Accessibility.NotApplicable,
                    Accessibility.NotApplicable,
                    indent
                );
            }

            if (!embedded)
            {
                // Serial constructor
                source.GenerateSerialCtor(compilation, className, indent, isOverride);
                source.AppendLine();
            }

            if (version > 0)
            {
                for (var i = 0; i < migrations.Length; i++)
                {
                    var migration = migrations[i];
                    if (migration.Version < version)
                    {
                        source.GenerateMigrationContentStruct(compilation, indent, migration, classSymbol);
                        source.AppendLine();
                    }
                }
            }

            // Serialize Method
            source.GenerateSerializeMethod(
                compilation,
                indent,
                isOverride,
                encodedVersion,
                serializableProperties,
                serializableFieldSaveFlags
            );
            source.AppendLine();

            // Deserialize Method
            source.GenerateDeserializeMethod(
                compilation,
                classSymbol,
                indent,
                isOverride,
                version,
                encodedVersion,
                migrations,
                serializableProperties,
                parentFieldOrProperty,
                serializableFieldSaveFlags
            );

            // Serialize SaveFlag enum class
            if (serializableFieldSaveFlags.Count > 0)
            {
                source.AppendLine();
                source.GenerateEnumStart(
                    "SaveFlag",
                    $"{indent}    ",
                    true,
                    Accessibility.Private
                );

                source.GenerateEnumValue($"{indent}        ", true, "None", -1);
                int index = 0;
                foreach (var (order, _) in serializableFieldSaveFlags)
                {
                    source.GenerateEnumValue($"{indent}    ", true, serializableProperties[order].Name, index++);
                }

                source.GenerateEnumEnd($"{indent}    ");
            }

            indent = indent.Substring(0, indent.Length - 4);
            source.RecursiveGenerateClassEnd(classSymbol, ref indent);
            source.GenerateNamespaceEnd();

            if (migrationPath != null)
            {
                // Write the migration file
                var newMigration = new SerializableMetadata
                {
                    Version = version,
                    Type = classSymbol.ToDisplayString(),
                    Properties = serializableProperties.Length > 0 ? serializableProperties : null
                };

                WriteMigration(migrationPath, newMigration, jsonSerializerOptions);
            }

            return source.ToString();
        }

        private static void WriteMigration(string migrationPath, SerializableMetadata metadata, JsonSerializerOptions options)
        {
            Directory.CreateDirectory(migrationPath);
            var filePath = Path.Combine(migrationPath, $"{metadata.Type}.v{metadata.Version}.json");
            File.WriteAllText(filePath, JsonSerializer.Serialize(metadata, options));
        }

        private static void RecursiveGenerateClassStart(
            this StringBuilder source,
            INamedTypeSymbol classSymbol,
            ImmutableArray<ITypeSymbol> interfaces,
            ref string indent
        )
        {
            var containingSymbolList = new List<INamedTypeSymbol>();

            do
            {
                containingSymbolList.Add(classSymbol);
                classSymbol = classSymbol.ContainingSymbol as INamedTypeSymbol;
            } while (classSymbol != null);

            containingSymbolList.Reverse();

            for (var i = 0; i < containingSymbolList.Count; i++)
            {
                var symbol = containingSymbolList[i];
                source.GenerateClassStart(symbol, indent, i == containingSymbolList.Count - 1 ? interfaces : ImmutableArray<ITypeSymbol>.Empty);
                indent += "    ";
            }
        }

        private static void RecursiveGenerateClassEnd(this StringBuilder source, INamedTypeSymbol classSymbol, ref string indent)
        {
            do
            {
                source.GenerateClassEnd(indent);
                indent = indent.Substring(0, indent.Length - 4);

                classSymbol = classSymbol.ContainingSymbol as INamedTypeSymbol;
            } while (classSymbol != null);
        }
    }
}