using System.Collections.Immutable;
using System.Linq;
using System.Text;
using Just.Railway.SourceGen.Executors.ResultExtensions.MainExtensions;
using Microsoft.CodeAnalysis;

namespace Just.Railway.SourceGen.Executors.ResultExtensions.ValueTaskExtensions;

internal class ResultValueTaskAppendExecutor : ResultAppendExecutor
{
    protected override string NamespaceName => "Just.Railway.ValueTaskExtensions";
    protected override string PartialClassName => "ResultValueTaskExtensions";

    protected override void GenerateHelperMethods(StringBuilder sb)
    {
        sb.AppendLine("""
        private static IEnumerable<string> GetBottom(ResultState r1, ResultState r2, string firstArg = "result", string secondArg = "next")
        {
            if (r1 == ResultState.Bottom)
                yield return firstArg;
            if (r2 == ResultState.Bottom)
                yield return secondArg;
        }
        """);
    }

    protected override void GenerateMethodsForArgCount(StringBuilder sb, int argCount)
    {
        var templateArgNames = Enumerable.Range(1, argCount)
            .Select(i => $"T{i}")
            .ToImmutableArray();

        string resultTypeDef = GenerateResultTypeDef(templateArgNames);
        string resultValueExpansion = GenerateResultValueExpansion(templateArgNames);

        sb.AppendLine($"#region {resultTypeDef}");

        GenerateAsyncMethods("ValueTask", "ValueTask", sb, templateArgNames, resultTypeDef, resultValueExpansion);

        if (argCount < Constants.MaxResultTupleSize)
        {
            GenerateExpandedAsyncMethods("ValueTask", "ValueTask", sb, templateArgNames, resultTypeDef, resultValueExpansion);
        }

        sb.AppendLine("#endregion");
    }
}