using System;
using System.Reflection;
using Svrnty.CQRS.Abstractions.Attributes;

namespace Svrnty.CQRS.Abstractions.Discovery;

public sealed class CommandMeta : ICommandMeta
{
    private readonly string _name;
    private readonly string _lowerCamelCaseName;

    public CommandMeta(Type commandType, Type serviceType, Type commandResultType)
    {
        CommandType = commandType;
        ServiceType = serviceType;
        CommandResultType = commandResultType;

        // Cache reflection and computed values once in constructor
        var nameAttribute = commandType.GetCustomAttribute<CommandNameAttribute>();
        _name = nameAttribute?.Name ?? commandType.Name.Replace("Command", string.Empty);
        _lowerCamelCaseName = ComputeLowerCamelCaseName(_name);
    }

    public CommandMeta(Type commandType, Type serviceType)
    {
        CommandType = commandType;
        ServiceType = serviceType;

        // Cache reflection and computed values once in constructor
        var nameAttribute = commandType.GetCustomAttribute<CommandNameAttribute>();
        _name = nameAttribute?.Name ?? commandType.Name.Replace("Command", string.Empty);
        _lowerCamelCaseName = ComputeLowerCamelCaseName(_name);
    }

    private static string ComputeLowerCamelCaseName(string name)
    {
        if (string.IsNullOrEmpty(name))
            return name;

        var firstLetter = char.ToLowerInvariant(name[0]);
        return $"{firstLetter}{name.Substring(1)}";
    }

    public string Name => _name;
    public Type CommandType { get; }
    public Type ServiceType { get; }
    public Type CommandResultType { get; }
    public string LowerCamelCaseName => _lowerCamelCaseName;
}