ReC/src/ReC.Application/Common/Procedures/StoredProcedureBuilder.cs

using Microsoft.Data.SqlClient;
using System.Data;
using System.Text;

namespace ReC.Application.Common.Procedures;

internal sealed class StoredProcedureBuilder(string procedureName, string? returnVariable = null)
{
    private readonly StringBuilder _execSql = returnVariable is not null
            ? new StringBuilder($"EXEC @{returnVariable} = {procedureName}")
            : new StringBuilder($"EXEC {procedureName}");
    private readonly List<SqlParameter> _parameters = [];
    private char _separator = ' ';

    public StoredProcedureBuilder Add(string name, object? value, SqlDbType? dbType = null)
    {
        if (value is null) return this;

        _execSql.AppendLine($"{_separator}@{name} = @{name}");
        _separator = ',';

        if (dbType.HasValue)
            _parameters.Add(new SqlParameter($"@{name}", dbType.Value) { Value = value });
        else
            _parameters.Add(new SqlParameter($"@{name}", value));

        return this;
    }

    public StoredProcedureBuilder AddOutput(string name, SqlDbType dbType)
    {
        _execSql.AppendLine($"{_separator}@{name} = @{name} OUTPUT");
        _separator = ',';

        _parameters.Add(new SqlParameter
        {
            ParameterName = $"@{name}",
            SqlDbType = dbType,
            Direction = ParameterDirection.Output
        });

        return this;
    }

    public string BuildSql()
    {
        if (returnVariable is null)
            return _execSql.ToString();

        return new StringBuilder()
            .AppendLine($"DECLARE @{returnVariable} SMALLINT = 0;")
            .Append(_execSql).AppendLine(";")
            .AppendLine($"SELECT @{returnVariable};")
            .ToString();
    }

    public SqlParameter[] BuildParameters() => [.. _parameters];

    public SqlParameter? GetParameter(string name) =>
        _parameters.Find(p => p.ParameterName == $"@{name}");
}