using System.Text.RegularExpressions;

namespace StellaOps.Microservice;

/// <summary>
/// Options for configuring a Stella microservice.
/// </summary>
public sealed partial class StellaMicroserviceOptions
{
    /// <summary>
    /// Gets or sets the service name.
    /// </summary>
    public required string ServiceName { get; set; }

    /// <summary>
    /// Gets or sets the semantic version.
    /// Must be valid semver (e.g., "1.0.0", "2.1.0-beta.1").
    /// </summary>
    public required string Version { get; set; }

    /// <summary>
    /// Gets or sets the region where this instance is deployed.
    /// </summary>
    public required string Region { get; set; }

    /// <summary>
    /// Gets or sets the unique instance identifier.
    /// Auto-generated if not provided.
    /// </summary>
    public string InstanceId { get; set; } = Guid.NewGuid().ToString("N");

    /// <summary>
    /// Gets the router endpoints to connect to.
    /// At least one router endpoint is required.
    /// </summary>
    public List<RouterEndpointConfig> Routers { get; set; } = [];

    /// <summary>
    /// Gets or sets the optional path to a YAML config file for endpoint overrides.
    /// </summary>
    public string? ConfigFilePath { get; set; }

    /// <summary>
    /// Gets or sets the heartbeat interval.
    /// Default: 10 seconds.
    /// </summary>
    public TimeSpan HeartbeatInterval { get; set; } = TimeSpan.FromSeconds(10);

    /// <summary>
    /// Gets or sets the maximum reconnect backoff.
    /// Default: 1 minute.
    /// </summary>
    public TimeSpan ReconnectBackoffMax { get; set; } = TimeSpan.FromMinutes(1);

    /// <summary>
    /// Gets or sets the initial reconnect delay.
    /// Default: 1 second.
    /// </summary>
    public TimeSpan ReconnectBackoffInitial { get; set; } = TimeSpan.FromSeconds(1);

    /// <summary>
    /// Validates the options and throws if invalid.
    /// </summary>
    public void Validate()
    {
        if (string.IsNullOrWhiteSpace(ServiceName))
            throw new InvalidOperationException("ServiceName is required.");

        if (string.IsNullOrWhiteSpace(Version))
            throw new InvalidOperationException("Version is required.");

        if (!SemverRegex().IsMatch(Version))
            throw new InvalidOperationException($"Version '{Version}' is not valid semver.");

        if (string.IsNullOrWhiteSpace(Region))
            throw new InvalidOperationException("Region is required.");

        if (Routers.Count == 0)
            throw new InvalidOperationException("At least one router endpoint is required.");

        foreach (var router in Routers)
        {
            if (string.IsNullOrWhiteSpace(router.Host))
                throw new InvalidOperationException("Router host is required.");
            if (router.Port <= 0 || router.Port > 65535)
                throw new InvalidOperationException($"Router port {router.Port} is invalid.");
        }
    }

    [GeneratedRegex(@"^(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)(?:-((?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*)(?:\.(?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*))*))?(?:\+([0-9a-zA-Z-]+(?:\.[0-9a-zA-Z-]+)*))?$")]
    private static partial Regex SemverRegex();
}