json-2-c-sharp-code-generator/Json2CSharpCodeGenerator.Lib/CodeWriters/PythonCodeWriter.cs

using System.Text;

namespace Json2CSharpCodeGenerator.Lib.CodeWriters;

public class PythonCodeWriter : ICodeBuilder
{
    public string FileExtension => throw new NotImplementedException();

    public string DisplayName => throw new NotImplementedException();

    public IReadOnlyCollection<string> ReservedKeywords => throw new NotImplementedException();

    public string GetTypeName(JsonType type, IJsonClassGeneratorConfig config)
    {
        return type.Type switch
        {
            JsonTypeEnum.Anything => "object",
            JsonTypeEnum.Array => GetCollectionTypeName(elementTypeName: GetTypeName(type.InternalType, config), config.CollectionType),
            // case JsonTypeEnum.Dictionary: return "Dictionary<string, " + this.GetTypeName(type.InternalType, config) + ">";
            JsonTypeEnum.Boolean => "bool",
            JsonTypeEnum.Float => "float",
            JsonTypeEnum.Integer => "int",
            JsonTypeEnum.Long => "float",
            //case JsonTypeEnum.Date: return "DateTime"; // Do Later
            JsonTypeEnum.Date => "str",
            JsonTypeEnum.NonConstrained => "object",
            // case JsonTypeEnum.NullableBoolean: return "bool?";
            //case JsonTypeEnum.NullableFloat: return "double?";
            //case JsonTypeEnum.NullableInteger: return "int?";
            //case JsonTypeEnum.NullableLong: return "long?";
            //case JsonTypeEnum.NullableDate: return "DateTime?";
            //case JsonTypeEnum.NullableSomething: return "object";
            JsonTypeEnum.Object => type.NewAssignedName,
            JsonTypeEnum.String => "str",
            _ => throw new NotSupportedException("Unsupported json type: " + type.Type),
        };
    }

    public string GetTypeFunctionName(JsonType type, IJsonClassGeneratorConfig config)
    {
        return type.Type switch
        {
            JsonTypeEnum.Anything => "",
            JsonTypeEnum.Array => "[" + type.InternalType.NewAssignedName + ".from_dict(y) for y in {0}]",
            // case JsonTypeEnum.Dictionary: return "Dictionary<string, " + this.GetTypeName(type.InternalType, config) + ">";
            JsonTypeEnum.Boolean => "",
            JsonTypeEnum.Float => "float({0})",
            JsonTypeEnum.Integer => "int({0})",
            JsonTypeEnum.Long => "float({0})",
            //case JsonTypeEnum.Date: return "DateTime"; // Do Later
            JsonTypeEnum.Date => "str({0})",
            JsonTypeEnum.NonConstrained => "",
            // case JsonTypeEnum.NullableBoolean: return "bool?";
            //case JsonTypeEnum.NullableFloat: return "double?";
            //case JsonTypeEnum.NullableInteger: return "int?";
            //case JsonTypeEnum.NullableLong: return "long?";
            //case JsonTypeEnum.NullableDate: return "DateTime?";
            //case JsonTypeEnum.NullableSomething: return "object";
            JsonTypeEnum.Object => type.NewAssignedName + ".from_dict({0})",
            JsonTypeEnum.String => "str({0})",
            _ => throw new NotSupportedException("Unsupported json type: " + type.Type),
        };
    }

    public bool IsReservedKeyword(string word) => throw new NotImplementedException();

    public void WriteClass(IJsonClassGeneratorConfig config, StringBuilder sw, JsonType type)
    {
        string className = type.AssignedName;

        _ = sw.AppendLine("@dataclass");
        _ = sw.AppendFormat("class {0}:{1}", className, Environment.NewLine);
        WriteClassMembers(config, sw, type, "");
        _ = sw.AppendLine();
    }

    public void WriteClassMembers(IJsonClassGeneratorConfig config, StringBuilder sw, JsonType type, string prefix)
    {
        StringBuilder fields = new();
        StringBuilder mappingFunction = new();
        foreach (FieldInfo field in type.Fields)
        {
            _ = field.MemberName;
            string propertyAttribute = field.JsonMemberName;
            string internalPropertyAttribute = "_" + propertyAttribute;
            _ = sw.AppendFormat("    {0}: {1}{2}", propertyAttribute, field.Type.GetTypeName(), Environment.NewLine);

            string mappingFragment = string.Format("obj.get(\"{0}\")", propertyAttribute);
            string mappingFragment2 = string.Format(GetTypeFunctionName(field.Type, config), mappingFragment);
            string mappingString = string.Format("        {0} = {1}", internalPropertyAttribute, mappingFragment2);
            _ = mappingFunction.AppendLine(mappingString);
            _ = fields.Append(internalPropertyAttribute + ", ");
        }

        // Remove trailing comma
        fields.Length--;
        fields.Length--;

        // Write Dictionnary Mapping Functions
        _ = sw.AppendLine();
        _ = sw.AppendLine("    @staticmethod");
        _ = sw.AppendLine(string.Format("    def from_dict(obj: Any) -> '{0}':", type.AssignedName));
        _ = sw.Append(mappingFunction.ToString());
        _ = sw.AppendLine(string.Format("        return {0}({1})", type.AssignedName, fields.ToString()));
    }

    public void WriteDeserializationComment(IJsonClassGeneratorConfig config, StringBuilder sw, bool rootIsArray = false)
    {
        return;
    }

    public void WriteFileEnd(IJsonClassGeneratorConfig config, StringBuilder sw)
    {
        _ = sw.Insert(0, "9 json" + Environment.NewLine);
        _ = sw.Insert(0, "from dataclasses import dataclass" + Environment.NewLine);
        _ = sw.Insert(0, "from typing import Any" + Environment.NewLine);
        if (sw.ToString().Contains("List"))
            _ = sw.Insert(0, string.Format("from typing import List{0}", Environment.NewLine));

        _ = sw.AppendLine("# Example Usage");
        _ = sw.AppendLine("# jsonstring = json.loads(myjsonstring)");
        _ = sw.AppendLine("# root = Root.from_dict(jsonstring)");
        return;
    }

    public void WriteFileStart(IJsonClassGeneratorConfig config, StringBuilder sw)
    {

        return;
    }

    public void WriteNamespaceEnd(IJsonClassGeneratorConfig config, StringBuilder sw, bool root)
    {

        return;
    }

    public void WriteNamespaceStart(IJsonClassGeneratorConfig config, StringBuilder sw, bool root)
    {
        return;
    }

    private static string GetCollectionTypeName(string elementTypeName, OutputCollectionType type)
    {
        return type switch
        {
            //case OutputCollectionType.Array: return elementTypeName + "[]";
            OutputCollectionType.Array => "List[" + elementTypeName + "]",
            OutputCollectionType.MutableList => "List[" + elementTypeName + "]",
            // case OutputCollectionType.IReadOnlyList: return "IReadOnlyList<" + elementTypeName + ">";
            // case OutputCollectionType.ImmutableArray: return "ImmutableArray<" + elementTypeName + ">";
            _ => throw new ArgumentOutOfRangeException(paramName: nameof(type), actualValue: type, message: "Invalid " + nameof(OutputCollectionType) + " enum value."),
        };
    }
}