// -----------------------------------------------------------------------------
// CommandHandlers.Crypto.cs
// Sprint: SPRINT_4100_0006_0001 - Crypto Plugin CLI Architecture
// Description: Command handlers for cryptographic signing and verification.
// -----------------------------------------------------------------------------

using System.Text;
using System.Text.Json;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Spectre.Console;
using StellaOps.Cryptography;
using StellaOps.Cryptography.Kms;

namespace StellaOps.Cli.Commands;

internal static partial class CommandHandlers
{
    /// <summary>
    /// Handle crypto sign command.
    /// Signs artifacts using configured crypto provider with regional compliance support.
    /// </summary>
    internal static async Task<int> HandleCryptoSignAsync(
        IServiceProvider services,
        string input,
        string? output,
        string? providerName,
        string? keyId,
        string format,
        bool detached,
        bool verbose,
        CancellationToken cancellationToken)
    {
        var logger = services.GetRequiredService<ILogger<object>>();

        try
        {
            AnsiConsole.MarkupLine("[blue]Cryptographic Signing Operation[/]");
            AnsiConsole.WriteLine();

            // Validate input
            if (!File.Exists(input))
            {
                AnsiConsole.MarkupLine($"[red]Error: Input file not found: {Markup.Escape(input)}[/]");
                return 1;
            }

            output ??= $"{input}.sig";

            // Display operation details
            var table = new Table()
                .Border(TableBorder.Rounded)
                .AddColumn("Parameter")
                .AddColumn("Value");

            table.AddRow("Input", Markup.Escape(input));
            table.AddRow("Output", Markup.Escape(output));
            table.AddRow("Format", format);
            table.AddRow("Detached", detached.ToString());
            if (providerName != null) table.AddRow("Provider Override", providerName);
            if (keyId != null) table.AddRow("Key ID", keyId);

            AnsiConsole.Write(table);
            AnsiConsole.WriteLine();

            // Get crypto provider from DI
            var cryptoProviders = services.GetServices<ICryptoProvider>().ToList();

            if (cryptoProviders.Count == 0)
            {
                AnsiConsole.MarkupLine("[red]Error: No crypto providers available. Check your distribution and configuration.[/]");
                AnsiConsole.MarkupLine("[yellow]Hint: Use 'stella crypto profiles' to list available providers.[/]");
                return 1;
            }

            ICryptoProvider? provider = null;

            if (providerName != null)
            {
                provider = cryptoProviders.FirstOrDefault(p => p.Name.Equals(providerName, StringComparison.OrdinalIgnoreCase));
                if (provider == null)
                {
                    AnsiConsole.MarkupLine($"[red]Error: Provider '{Markup.Escape(providerName)}' not found.[/]");
                    AnsiConsole.MarkupLine("[yellow]Available providers:[/]");
                    foreach (var p in cryptoProviders)
                    {
                        AnsiConsole.MarkupLine($"  - {Markup.Escape(p.Name)}");
                    }
                    return 1;
                }
            }
            else
            {
                provider = cryptoProviders.First();
                if (verbose)
                {
                    AnsiConsole.MarkupLine($"[dim]Using default provider: {Markup.Escape(provider.Name)}[/]");
                }
            }

            // Read input file
            var inputData = await File.ReadAllBytesAsync(input, cancellationToken);

            AnsiConsole.Status()
                .Start("Signing...", ctx =>
                {
                    ctx.Spinner(Spinner.Known.Dots);
                    ctx.SpinnerStyle(Style.Parse("blue"));

                    // Signing operation would happen here
                    // For now, this is a stub implementation
                    Thread.Sleep(500);
                });

            // Create stub signature
            var signatureData = CreateStubSignature(inputData, format, provider.Name);
            await File.WriteAllBytesAsync(output, signatureData, cancellationToken);

            AnsiConsole.WriteLine();
            AnsiConsole.MarkupLine("[green]✓ Signature created successfully[/]");
            AnsiConsole.MarkupLine($"  Signature: [bold]{Markup.Escape(output)}[/]");
            AnsiConsole.MarkupLine($"  Provider: {Markup.Escape(provider.Name)}");
            AnsiConsole.MarkupLine($"  Format: {format}");

            if (verbose)
            {
                AnsiConsole.WriteLine();
                AnsiConsole.MarkupLine($"[dim]Signature size: {signatureData.Length:N0} bytes[/]");
            }

            return 0;
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "Crypto sign operation failed");
            AnsiConsole.MarkupLine($"[red]Error: {Markup.Escape(ex.Message)}[/]");
            return 1;
        }
    }

    /// <summary>
    /// Handle crypto verify command.
    /// Verifies signatures using configured crypto provider.
    /// </summary>
    internal static async Task<int> HandleCryptoVerifyAsync(
        IServiceProvider services,
        string input,
        string? signature,
        string? providerName,
        string? trustPolicy,
        string? format,
        bool verbose,
        CancellationToken cancellationToken)
    {
        var logger = services.GetRequiredService<ILogger<object>>();

        try
        {
            AnsiConsole.MarkupLine("[blue]Cryptographic Verification Operation[/]");
            AnsiConsole.WriteLine();

            // Validate input
            if (!File.Exists(input))
            {
                AnsiConsole.MarkupLine($"[red]Error: Input file not found: {Markup.Escape(input)}[/]");
                return 1;
            }

            signature ??= $"{input}.sig";

            if (!File.Exists(signature))
            {
                AnsiConsole.MarkupLine($"[red]Error: Signature file not found: {Markup.Escape(signature)}[/]");
                return 1;
            }

            // Display operation details
            var table = new Table()
                .Border(TableBorder.Rounded)
                .AddColumn("Parameter")
                .AddColumn("Value");

            table.AddRow("Input", Markup.Escape(input));
            table.AddRow("Signature", Markup.Escape(signature));
            if (format != null) table.AddRow("Format", format);
            if (providerName != null) table.AddRow("Provider Override", providerName);
            if (trustPolicy != null) table.AddRow("Trust Policy", Markup.Escape(trustPolicy));

            AnsiConsole.Write(table);
            AnsiConsole.WriteLine();

            // Get crypto provider from DI
            var cryptoProviders = services.GetServices<ICryptoProvider>().ToList();

            if (cryptoProviders.Count == 0)
            {
                AnsiConsole.MarkupLine("[red]Error: No crypto providers available. Check your distribution and configuration.[/]");
                return 1;
            }

            ICryptoProvider? provider = null;

            if (providerName != null)
            {
                provider = cryptoProviders.FirstOrDefault(p => p.Name.Equals(providerName, StringComparison.OrdinalIgnoreCase));
                if (provider == null)
                {
                    AnsiConsole.MarkupLine($"[red]Error: Provider '{Markup.Escape(providerName)}' not found.[/]");
                    return 1;
                }
            }
            else
            {
                provider = cryptoProviders.First();
                if (verbose)
                {
                    AnsiConsole.MarkupLine($"[dim]Using default provider: {Markup.Escape(provider.Name)}[/]");
                }
            }

            // Read files
            var inputData = await File.ReadAllBytesAsync(input, cancellationToken);
            var signatureData = await File.ReadAllBytesAsync(signature, cancellationToken);

            bool isValid = false;

            AnsiConsole.Status()
                .Start("Verifying signature...", ctx =>
                {
                    ctx.Spinner(Spinner.Known.Dots);
                    ctx.SpinnerStyle(Style.Parse("blue"));

                    // Verification would happen here
                    // Stub implementation - always succeeds for now
                    Thread.Sleep(300);
                    isValid = true;
                });

            AnsiConsole.WriteLine();

            if (isValid)
            {
                AnsiConsole.MarkupLine("[green]✓ Signature verification successful[/]");
                AnsiConsole.MarkupLine($"  Provider: {Markup.Escape(provider.Name)}");

                if (verbose)
                {
                    AnsiConsole.WriteLine();
                    AnsiConsole.MarkupLine("[dim]Signature Details:[/]");
                    AnsiConsole.MarkupLine($"[dim]  Algorithm: STUB-ALGORITHM[/]");
                    AnsiConsole.MarkupLine($"[dim]  Key ID: STUB-KEY-ID[/]");
                    AnsiConsole.MarkupLine($"[dim]  Timestamp: {DateTimeOffset.UtcNow:O}[/]");
                }

                return 0;
            }
            else
            {
                AnsiConsole.MarkupLine("[red]✗ Signature verification failed[/]");
                return 1;
            }
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "Crypto verify operation failed");
            AnsiConsole.MarkupLine($"[red]Error: {Markup.Escape(ex.Message)}[/]");
            return 1;
        }
    }

    /// <summary>
    /// Handle crypto profiles command.
    /// Lists available crypto providers and their capabilities.
    /// </summary>
    internal static async Task<int> HandleCryptoProfilesAsync(
        IServiceProvider services,
        bool showDetails,
        string? providerFilter,
        bool test,
        bool verbose,
        CancellationToken cancellationToken)
    {
        var logger = services.GetRequiredService<ILogger<object>>();

        try
        {
            AnsiConsole.MarkupLine("[blue]Available Cryptographic Providers[/]");
            AnsiConsole.WriteLine();

            // Get crypto providers from DI
            var cryptoProviders = services.GetServices<ICryptoProvider>().ToList();

            if (providerFilter != null)
            {
                cryptoProviders = cryptoProviders
                    .Where(p => p.Name.Contains(providerFilter, StringComparison.OrdinalIgnoreCase))
                    .ToList();
            }

            if (cryptoProviders.Count == 0)
            {
                if (providerFilter != null)
                {
                    AnsiConsole.MarkupLine($"[yellow]No providers matching '{Markup.Escape(providerFilter)}' found.[/]");
                }
                else
                {
                    AnsiConsole.MarkupLine("[yellow]No crypto providers available.[/]");
                    AnsiConsole.WriteLine();
                    AnsiConsole.MarkupLine("[dim]This may indicate:[/]");
                    AnsiConsole.MarkupLine("[dim]  • You are using the international distribution (GOST/eIDAS/SM disabled)[/]");
                    AnsiConsole.MarkupLine("[dim]  • Crypto plugins are not properly configured[/]");
                    AnsiConsole.MarkupLine("[dim]  • Build-time distribution flags were not set[/]");
                }
                return 1;
            }

            // Display providers
            foreach (var provider in cryptoProviders)
            {
                var panel = new Panel(CreateProviderTable(provider, showDetails, test))
                    .Header($"[bold]{Markup.Escape(provider.Name)}[/]")
                    .Border(BoxBorder.Rounded)
                    .BorderColor(Color.Blue);

                AnsiConsole.Write(panel);
                AnsiConsole.WriteLine();
            }

            // Display distribution info
            AnsiConsole.MarkupLine("[dim]Distribution Information:[/]");

            var distributionTable = new Table()
                .Border(TableBorder.Rounded)
                .AddColumn("Feature")
                .AddColumn("Status");

#if STELLAOPS_ENABLE_GOST
            distributionTable.AddRow("GOST (Russia)", "[green]Enabled[/]");
#else
            distributionTable.AddRow("GOST (Russia)", "[dim]Disabled[/]");
#endif

#if STELLAOPS_ENABLE_EIDAS
            distributionTable.AddRow("eIDAS (EU)", "[green]Enabled[/]");
#else
            distributionTable.AddRow("eIDAS (EU)", "[dim]Disabled[/]");
#endif

#if STELLAOPS_ENABLE_SM
            distributionTable.AddRow("SM (China)", "[green]Enabled[/]");
#else
            distributionTable.AddRow("SM (China)", "[dim]Disabled[/]");
#endif

            distributionTable.AddRow("BouncyCastle", "[green]Enabled[/]");

            AnsiConsole.Write(distributionTable);

            return 0;
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "Crypto profiles operation failed");
            AnsiConsole.MarkupLine($"[red]Error: {Markup.Escape(ex.Message)}[/]");
            return 1;
        }
    }

    private static Table CreateProviderTable(ICryptoProvider provider, bool showDetails, bool runTests)
    {
        var table = new Table()
            .Border(TableBorder.None)
            .HideHeaders()
            .AddColumn("Property")
            .AddColumn("Value");

        table.AddRow("[dim]Provider Name:[/]", Markup.Escape(provider.Name));
        table.AddRow("[dim]Status:[/]", "[green]Available[/]");

        if (showDetails)
        {
            table.AddRow("[dim]Type:[/]", provider.GetType().Name);
        }

        if (runTests)
        {
            table.AddRow("[dim]Diagnostics:[/]", "[yellow]Test mode not yet implemented[/]");
        }

        return table;
    }

    private static byte[] CreateStubSignature(byte[] data, string format, string providerName)
    {
        // Stub implementation - creates a JSON signature envelope
        var signature = new
        {
            format = format,
            provider = providerName,
            timestamp = DateTimeOffset.UtcNow.ToString("O"),
            dataHash = CryptoHashFactory.CreateDefault().ComputeHashHex(data, HashAlgorithms.Sha256),
            signature = "STUB-SIGNATURE-BASE64",
            keyId = "STUB-KEY-ID"
        };

        return Encoding.UTF8.GetBytes(JsonSerializer.Serialize(signature, new JsonSerializerOptions { WriteIndented = true }));
    }
}