classlib/ExpenseTracker.Persistence/MongoDb/Serializers/TransactionSerializer.cs

using MongoDB.Bson;
using MongoDB.Bson.IO;
using MongoDB.Bson.Serialization;
using MongoDB.Bson.Serialization.Serializers;
using ExpenseTracker.Domain.Entities;
using ExpenseTracker.Domain.Enums;

namespace ExpenseTracker.Persistence.Serializers;

public class TransactionSerializer : SerializerBase<Transaction>, IBsonDocumentSerializer
{
    private const string IdDeserializedFieldName = "Id";
    private const string IdSerializedFieldName = "_id";

    private const string AmountDeserializedFieldName = "Amount";
    private const string AmountSerializedFieldName = "amount";

    private const string CategoryDeserializedFieldName = "Category";
    private const string CategorySerializedFieldName = "category";

    private const string TimeDeserializedFieldName = "Time";
    private const string TimeSerializedFieldName = "time";

    private const string DescriptionDeserializedFieldName = "Description";
    private const string DescriptionSerializedFieldName = "description";

    private const string AccountIdDeserializedFieldName = "AccountId";
    private const string AccountIdSerializedFieldName = "accountId";

    public override Transaction Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args)
    {
        context.Reader.ReadStartDocument();

        var entity = new Transaction();

        while (context.Reader.ReadBsonType() != BsonType.EndOfDocument)
        {
            var fieldName = context.Reader.ReadName();

            switch (fieldName)
            {
                case IdSerializedFieldName:
                    entity.Id = context.Reader.ReadString();
                    break;
                case AmountSerializedFieldName:
                    entity.Amount = context.Reader.ReadDouble();
                    break;
                case CategorySerializedFieldName:
                    entity.Category = Category.FromName(context.Reader.ReadString());
                    break;
                case TimeSerializedFieldName:
                    entity.Time = DateTimeOffset.FromUnixTimeMilliseconds(context.Reader.ReadDateTime());
                    break;
                case DescriptionSerializedFieldName:
                    var description = context.Reader.ReadString();
                    entity.Description = description.Equals(String.Empty) ? null : description;
                    break;
                case AccountIdSerializedFieldName:
                    entity.AccountId = context.Reader.ReadString();
                    break;
            }
        }

        context.Reader.ReadEndDocument();

        return entity;
    }

    public override void Serialize(BsonSerializationContext context, BsonSerializationArgs args, Transaction value)
    {
        context.Writer.WriteStartDocument();

        context.Writer.WriteString(IdSerializedFieldName, value.Id);
        context.Writer.WriteDouble(AmountSerializedFieldName, value.Amount);
        context.Writer.WriteString(CategorySerializedFieldName, value.Category.Name);
        context.Writer.WriteDateTime(TimeSerializedFieldName, value.Time.ToUnixTimeMilliseconds());
        context.Writer.WriteString(DescriptionSerializedFieldName, value.Description ?? String.Empty);
        context.Writer.WriteString(AccountIdSerializedFieldName, value.AccountId);

        context.Writer.WriteEndDocument();
    }

    public bool TryGetMemberSerializationInfo(string memberName, out BsonSerializationInfo serializationInfo)
    {
        switch (memberName)
        {
            case IdDeserializedFieldName:
                serializationInfo = new BsonSerializationInfo(IdSerializedFieldName, new StringSerializer(), typeof(string));
                return true;
            case AmountDeserializedFieldName:
                serializationInfo = new BsonSerializationInfo(AmountSerializedFieldName, new DoubleSerializer(), typeof(double));
                return true;
            case CategoryDeserializedFieldName:
                serializationInfo = new BsonSerializationInfo(CategorySerializedFieldName, new StringSerializer(), typeof(string));
                return true;
            case TimeDeserializedFieldName:
                serializationInfo = new BsonSerializationInfo(TimeSerializedFieldName, new DateTimeSerializer(), typeof(DateTimeOffset));
                return true;
            case DescriptionDeserializedFieldName:
                serializationInfo = new BsonSerializationInfo(DescriptionSerializedFieldName, new StringSerializer(), typeof(string));
                return true;
            case AccountIdDeserializedFieldName:
                serializationInfo = new BsonSerializationInfo(AccountIdSerializedFieldName, new StringSerializer(), typeof(string));
                return true;
            default:
                serializationInfo = null;
                return false;
        }
    }
}