using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using Serilog;
using System.Text.Json;
using ZB.MOM.WW.CBDDC.Core.Network;
using ZB.MOM.WW.CBDDC.Core.Storage;
using ZB.MOM.WW.CBDDC.Core.Sync;
using ZB.MOM.WW.CBDDC.Network;
using ZB.MOM.WW.CBDDC.Persistence.Snapshot;
using ZB.MOM.WW.CBDDC.Persistence.Surreal;

namespace ZB.MOM.WW.CBDDC.Sample.Console;

// Local User/Address classes removed in favor of Shared project

internal class Program
{
    private static async Task Main(string[] args)
    {
        if (await TryRunMigrationAsync(args)) return;

        var builder = Host.CreateApplicationBuilder(args);

        // Configuration
        builder.Configuration.SetBasePath(Directory.GetCurrentDirectory())
            .AddJsonFile("appsettings.json", true, true);

        // Logging
        builder.Logging.ClearProviders();
        builder.Services.AddSerilog((_, loggerConfiguration) =>
            loggerConfiguration
                .MinimumLevel.Information()
                .Enrich.FromLogContext()
                .Enrich.WithProperty("Application", "CBDDC.Sample.Console")
                .WriteTo.Console());

        int randomPort = new Random().Next(1000, 9999);
        // Node ID
        string nodeId = args.Length > 0 ? args[0] : "node-" + randomPort;
        int tcpPort = args.Length > 1 ? int.Parse(args[1]) : randomPort;


        // Conflict Resolution Strategy (can be switched at runtime via service replacement)
        bool useRecursiveMerge = args.Contains("--merge");
        if (useRecursiveMerge) builder.Services.AddSingleton<IConflictResolver, RecursiveNodeMergeConflictResolver>();

        IPeerNodeConfigurationProvider peerNodeConfigurationProvider = new StaticPeerNodeConfigurationProvider(
            new PeerNodeConfiguration
            {
                NodeId = nodeId,
                TcpPort = tcpPort,
                AuthToken = "Test-Cluster-Key"
                //KnownPeers = builder.Configuration.GetSection("CBDDC:KnownPeers").Get<List<KnownPeerConfiguration>>() ?? new()
            });

        builder.Services.AddSingleton(peerNodeConfigurationProvider);

        // Database path
        string dataPath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "data");
        Directory.CreateDirectory(dataPath);
        string databasePath = Path.Combine(dataPath, $"{nodeId}.rocksdb");
        string surrealDatabase = nodeId.Replace("-", "_", StringComparison.Ordinal);

        // Register CBDDC services with embedded Surreal (RocksDB).
        builder.Services.AddSingleton<ICBDDCSurrealSchemaInitializer, SampleSurrealSchemaInitializer>();
        builder.Services.AddSingleton<SampleDbContext>();
        builder.Services.AddCBDDCCore()
            .AddCBDDCSurrealEmbedded<SampleDocumentStore>(_ => new CBDDCSurrealEmbeddedOptions
            {
                Endpoint = "rocksdb://local",
                DatabasePath = databasePath,
                Namespace = "cbddc_sample",
                Database = surrealDatabase
            })
            .AddCBDDCNetwork<StaticPeerNodeConfigurationProvider>(); // useHostedService = true by default

        builder.Services.AddHostedService<ConsoleInteractiveService>(); // Runs the Input Loop

        var host = builder.Build();

        System.Console.WriteLine($"? Node {nodeId} initialized on port {tcpPort}");
        System.Console.WriteLine($"? Database: {databasePath}");
        System.Console.WriteLine();

        await host.RunAsync();
    }

    private static async Task<bool> TryRunMigrationAsync(string[] args)
    {
        int migrateIndex = Array.IndexOf(args, "--migrate-snapshot");
        if (migrateIndex < 0) return false;

        string snapshotPath = GetRequiredArgumentValue(args, migrateIndex, "--migrate-snapshot");
        if (!File.Exists(snapshotPath))
            throw new FileNotFoundException("Snapshot file not found.", snapshotPath);

        string targetPath = GetOptionalArgumentValue(args, "--target-db")
                            ?? Path.Combine(Directory.GetCurrentDirectory(), "data", "migration.rocksdb");
        Directory.CreateDirectory(Path.GetDirectoryName(Path.GetFullPath(targetPath))!);

        string nodeId = "migration-node";
        var configProvider = new StaticPeerNodeConfigurationProvider(new PeerNodeConfiguration
        {
            NodeId = nodeId,
            TcpPort = 0,
            AuthToken = "migration"
        });

        string databaseName = $"migration_{DateTimeOffset.UtcNow.ToUnixTimeSeconds()}";
        var services = new ServiceCollection();
        services.AddLogging();
        services.AddSingleton<IPeerNodeConfigurationProvider>(configProvider);
        services.AddSingleton<ICBDDCSurrealSchemaInitializer, SampleSurrealSchemaInitializer>();
        services.AddSingleton<SampleDbContext>();
        services.AddCBDDCCore()
            .AddCBDDCSurrealEmbedded<SampleDocumentStore>(_ => new CBDDCSurrealEmbeddedOptions
            {
                Endpoint = "rocksdb://local",
                DatabasePath = targetPath,
                Namespace = "cbddc_migration",
                Database = databaseName
            });

        using var provider = services.BuildServiceProvider();
        var snapshotService = provider.GetRequiredService<ISnapshotService>();
        await using (var snapshotStream = File.OpenRead(snapshotPath))
        {
            await snapshotService.ReplaceDatabaseAsync(snapshotStream);
        }

        await VerifyMigrationAsync(provider, snapshotPath);
        System.Console.WriteLine($"Migration completed successfully to: {targetPath}");
        return true;
    }

    private static async Task VerifyMigrationAsync(IServiceProvider provider, string snapshotPath)
    {
        await using var snapshotStream = File.OpenRead(snapshotPath);
        var source = await JsonSerializer.DeserializeAsync<SnapshotDto>(snapshotStream)
                     ?? throw new InvalidOperationException("Unable to deserialize source snapshot.");

        var documentStore = provider.GetRequiredService<IDocumentStore>();
        var oplogStore = provider.GetRequiredService<IOplogStore>();
        var peerStore = provider.GetRequiredService<IPeerConfigurationStore>();
        var confirmationStore = provider.GetService<IPeerOplogConfirmationStore>();

        int destinationDocuments = (await documentStore.ExportAsync()).Count();
        int destinationOplog = (await oplogStore.ExportAsync()).Count();
        int destinationPeers = (await peerStore.ExportAsync()).Count();
        int destinationConfirmations = confirmationStore == null
            ? 0
            : (await confirmationStore.ExportAsync()).Count();

        if (destinationDocuments != source.Documents.Count ||
            destinationOplog != source.Oplog.Count ||
            destinationPeers != source.RemotePeers.Count ||
            destinationConfirmations != source.PeerConfirmations.Count)
            throw new InvalidOperationException("Snapshot parity verification failed after migration.");

        if (source.Oplog.Count > 0)
        {
            string firstHash = source.Oplog[0].Hash;
            string lastHash = source.Oplog[^1].Hash;

            var firstEntry = await oplogStore.GetEntryByHashAsync(firstHash);
            var lastEntry = await oplogStore.GetEntryByHashAsync(lastHash);
            if (firstEntry == null || lastEntry == null)
                throw new InvalidOperationException("Oplog hash spot-check failed after migration.");
        }
    }

    private static string GetRequiredArgumentValue(string[] args, int optionIndex, string optionName)
    {
        if (optionIndex < 0 || optionIndex + 1 >= args.Length || args[optionIndex + 1].StartsWith("--"))
            throw new ArgumentException($"Missing value for {optionName}.");

        return args[optionIndex + 1];
    }

    private static string? GetOptionalArgumentValue(string[] args, string optionName)
    {
        int index = Array.IndexOf(args, optionName);
        if (index < 0) return null;
        if (index + 1 >= args.Length || args[index + 1].StartsWith("--"))
            throw new ArgumentException($"Missing value for {optionName}.");
        return args[index + 1];
    }

    private class StaticPeerNodeConfigurationProvider : IPeerNodeConfigurationProvider
    {
        /// <summary>
        ///     Initializes a new instance of the <see cref="StaticPeerNodeConfigurationProvider" /> class.
        /// </summary>
        /// <param name="configuration">The initial peer node configuration.</param>
        public StaticPeerNodeConfigurationProvider(PeerNodeConfiguration configuration)
        {
            Configuration = configuration;
        }

        /// <summary>
        ///     Gets or sets the current peer node configuration.
        /// </summary>
        public PeerNodeConfiguration Configuration { get; }

        /// <summary>
        ///     Occurs when the peer node configuration changes.
        /// </summary>
        public event PeerNodeConfigurationChangedEventHandler? ConfigurationChanged;

        /// <summary>
        ///     Gets the current peer node configuration.
        /// </summary>
        /// <returns>A task that returns the current configuration.</returns>
        public Task<PeerNodeConfiguration> GetConfiguration()
        {
            return Task.FromResult(Configuration);
        }

        /// <summary>
        ///     Raises the configuration changed event.
        /// </summary>
        /// <param name="newConfig">The new configuration value.</param>
        protected virtual void OnConfigurationChanged(PeerNodeConfiguration newConfig)
        {
            ConfigurationChanged?.Invoke(this, newConfig);
        }
    }
}