using System.Text.RegularExpressions;
using Tomlyn;

namespace Luna.Configuration.Services.Agents;

internal sealed class AgentOptionsProvider(string? searchPath = null)
{
    private readonly EmbeddedResourceLoader embeddedResourceLoader = new();
    
    public IEnumerable<AgentOptions> GetAgentOptions()
    {
        return string.IsNullOrWhiteSpace(searchPath)
            ? GetAgentOptionsFromEmbeddedResources()
            : GetAgentOptionsFromFiles();
    }

    private IEnumerable<AgentOptions> GetAgentOptionsFromFiles()
    {
        ArgumentException.ThrowIfNullOrEmpty(searchPath);

        var files = Directory.Exists(searchPath)
            ? Directory.EnumerateFiles(searchPath, "Agent.*.toml")
            : [];
        
        foreach (var file in files)
        {
            using var reader = File.OpenText(file);
            var agentOptions = TomlSerializer.Deserialize<AgentOptions>(reader);
            
            yield return agentOptions
                ?? throw new FormatException($"Invalid agent config file: {file}");
        }
    }
    
    private IEnumerable<AgentOptions> GetAgentOptionsFromEmbeddedResources()
    {
        var resources = embeddedResourceLoader.ListResources("Agent.*.toml");
        foreach (var resource in resources)
        {
            var content = embeddedResourceLoader.LoadAsync(resource).GetAwaiter().GetResult();
            var agentOptions = TomlSerializer.Deserialize<AgentOptions>(content);
            
            yield return agentOptions
                ?? throw new FormatException($"Invalid agent config embedded resource: {resource}");
        }
    }
}

internal static partial class StringExtensions
{
    [GeneratedRegex(@"Agent\.(.+)\.toml", RegexOptions.IgnoreCase | RegexOptions.Compiled)]
    private static partial Regex AgentNameRegex { get; }
    
    extension(string str)
    {
        public string ToAgentName() => AgentNameRegex.Match(str) is { Success: true } match
            ? match.Groups[1].Value
            : throw new FormatException($"Invalid agent config file name: {str}");
    }
}