using System.Text.Json;
using System.Text.Json.Serialization;
using Microsoft.Extensions.Logging;
using ZB.MOM.WW.OtOpcUa.Core.Hosting;
using ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Config;

namespace ZB.MOM.WW.OtOpcUa.Driver.Galaxy;

/// <summary>
///     Static factory registration helper for <see cref="GalaxyDriver"/>. Mirrors
///     <c>GalaxyProxyDriverFactoryExtensions</c> / <c>ModbusDriverFactoryExtensions</c>.
///     Server's <c>Program.cs</c> calls <see cref="Register"/> once at startup; the driver
///     bootstrap pipeline materialises DriverInstance rows whose <c>DriverType</c> matches
///     <see cref="DriverTypeName"/> into live <see cref="GalaxyDriver"/> instances.
/// </summary>
/// <remarks>
///     The driver-type name <c>"GalaxyMxGateway"</c> is intentionally distinct from the
///     legacy proxy's <c>"Galaxy"</c> so both factories can be registered simultaneously
///     during parity testing (Phase 5). PR 4.W will add a server-side <c>Galaxy:Backend</c>
///     switch that materialises a Galaxy DriverInstance under one or the other type name.
/// </remarks>
public static class GalaxyDriverFactoryExtensions
{
    public const string DriverTypeName = "GalaxyMxGateway";

    public static void Register(DriverFactoryRegistry registry, ILoggerFactory? loggerFactory = null)
    {
        ArgumentNullException.ThrowIfNull(registry);
        registry.Register(DriverTypeName, (id, json) => CreateInstance(id, json, loggerFactory));
    }

    /// <summary>Convenience for tests + standalone callers.</summary>
    public static GalaxyDriver CreateInstance(string driverInstanceId, string driverConfigJson)
        => CreateInstance(driverInstanceId, driverConfigJson, loggerFactory: null);

    public static GalaxyDriver CreateInstance(
        string driverInstanceId, string driverConfigJson, ILoggerFactory? loggerFactory)
    {
        ArgumentException.ThrowIfNullOrWhiteSpace(driverInstanceId);
        ArgumentException.ThrowIfNullOrWhiteSpace(driverConfigJson);

        var dto = JsonSerializer.Deserialize<GalaxyDriverConfigDto>(driverConfigJson, JsonOptions)
            ?? throw new InvalidOperationException(
                $"Galaxy driver config for '{driverInstanceId}' deserialised to null");

        var options = new GalaxyDriverOptions(
            Gateway: new GalaxyGatewayOptions(
                Endpoint: dto.Gateway?.Endpoint
                    ?? throw new InvalidOperationException(
                        $"Galaxy driver '{driverInstanceId}' missing required Gateway.Endpoint"),
                ApiKeySecretRef: dto.Gateway.ApiKeySecretRef
                    ?? throw new InvalidOperationException(
                        $"Galaxy driver '{driverInstanceId}' missing required Gateway.ApiKeySecretRef"),
                UseTls: dto.Gateway.UseTls ?? true,
                CaCertificatePath: dto.Gateway.CaCertificatePath,
                ConnectTimeoutSeconds: dto.Gateway.ConnectTimeoutSeconds ?? 10,
                DefaultCallTimeoutSeconds: dto.Gateway.DefaultCallTimeoutSeconds ?? 30,
                StreamTimeoutSeconds: dto.Gateway.StreamTimeoutSeconds ?? 0),
            MxAccess: new GalaxyMxAccessOptions(
                ClientName: dto.MxAccess?.ClientName
                    ?? throw new InvalidOperationException(
                        $"Galaxy driver '{driverInstanceId}' missing required MxAccess.ClientName"),
                PublishingIntervalMs: dto.MxAccess.PublishingIntervalMs ?? 1000,
                WriteUserId: dto.MxAccess.WriteUserId ?? 0,
                EventPumpChannelCapacity: dto.MxAccess.EventPumpChannelCapacity ?? 50_000),
            Repository: new GalaxyRepositoryOptions(
                DiscoverPageSize: dto.Repository?.DiscoverPageSize ?? 5000,
                WatchDeployEvents: dto.Repository?.WatchDeployEvents ?? true),
            Reconnect: new GalaxyReconnectOptions(
                InitialBackoffMs: dto.Reconnect?.InitialBackoffMs ?? 500,
                MaxBackoffMs: dto.Reconnect?.MaxBackoffMs ?? 30_000,
                ReplayOnSessionLost: dto.Reconnect?.ReplayOnSessionLost ?? true));

        return new GalaxyDriver(driverInstanceId, options, loggerFactory?.CreateLogger<GalaxyDriver>());
    }

    private static readonly JsonSerializerOptions JsonOptions = new()
    {
        PropertyNameCaseInsensitive = true,
        ReadCommentHandling = JsonCommentHandling.Skip,
        AllowTrailingCommas = true,
    };

    internal sealed class GalaxyDriverConfigDto
    {
        public GatewayDto? Gateway { get; init; }
        public MxAccessDto? MxAccess { get; init; }
        public RepositoryDto? Repository { get; init; }
        public ReconnectDto? Reconnect { get; init; }
    }

    internal sealed class GatewayDto
    {
        public string? Endpoint { get; init; }
        public string? ApiKeySecretRef { get; init; }
        public bool? UseTls { get; init; }
        public string? CaCertificatePath { get; init; }
        public int? ConnectTimeoutSeconds { get; init; }
        public int? DefaultCallTimeoutSeconds { get; init; }
        public int? StreamTimeoutSeconds { get; init; }
    }

    internal sealed class MxAccessDto
    {
        public string? ClientName { get; init; }
        public int? PublishingIntervalMs { get; init; }
        public int? WriteUserId { get; init; }
        public int? EventPumpChannelCapacity { get; init; }
    }

    internal sealed class RepositoryDto
    {
        public int? DiscoverPageSize { get; init; }
        public bool? WatchDeployEvents { get; init; }
    }

    internal sealed class ReconnectDto
    {
        public int? InitialBackoffMs { get; init; }
        public int? MaxBackoffMs { get; init; }
        public bool? ReplayOnSessionLost { get; init; }
    }
}