using System.Diagnostics;
using System.Text.Json.Serialization;

var builder = WebApplication.CreateSlimBuilder(args);
builder.Services.ConfigureHttpJsonOptions(opts =>
{
    opts.SerializerOptions.DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull;
});

var app = builder.Build();

const string CsptestPath = "/opt/cprocsp/bin/amd64/csptest";

app.MapGet("/health", () =>
{
    if (!File.Exists(CsptestPath))
    {
        return Results.Problem(statusCode: 500, detail: "csptest not found; ensure CryptoPro CSP is installed");
    }

    return Results.Ok(new { status = "ok", csptest = CsptestPath });
});

app.MapGet("/license", () =>
{
    var result = RunProcess([CsptestPath, "-keyset", "-info"], allowFailure: true);
    return Results.Json(result);
});

app.MapPost("/hash", async (HashRequest request) =>
{
    byte[] data;
    try
    {
        data = Convert.FromBase64String(request.DataBase64);
    }
    catch (FormatException)
    {
        return Results.BadRequest(new { error = "Invalid base64" });
    }

    var inputPath = Path.GetTempFileName();
    var outputPath = Path.GetTempFileName();
    await File.WriteAllBytesAsync(inputPath, data);

    var result = RunProcess([CsptestPath, "-hash", "-alg", "GOST12_256", "-in", inputPath, "-out", outputPath], allowFailure: true);
    string? digestBase64 = null;
    if (File.Exists(outputPath))
    {
        var digestBytes = await File.ReadAllBytesAsync(outputPath);
        digestBase64 = Convert.ToBase64String(digestBytes);
    }

    TryDelete(inputPath);
    TryDelete(outputPath);

    return Results.Json(new
    {
        result.ExitCode,
        result.Output,
        digest_b64 = digestBase64
    });
});

app.MapPost("/keyset/init", (KeysetRequest request) =>
{
    var name = string.IsNullOrWhiteSpace(request.Name) ? "default" : request.Name!;
    var result = RunProcess([CsptestPath, "-keyset", "-newkeyset", "-container", name, "-keytype", "none"], allowFailure: true);
    return Results.Json(result);
});

app.Run("http://0.0.0.0:8080");

static void TryDelete(string path)
{
    try { File.Delete(path); } catch { /* ignore */ }
}

static ProcessResult RunProcess(string[] args, bool allowFailure = false)
{
    try
    {
        var psi = new ProcessStartInfo
        {
            FileName = args[0],
            RedirectStandardOutput = true,
            RedirectStandardError = true,
            UseShellExecute = false,
            ArgumentList = { }
        };
        for (var i = 1; i < args.Length; i++)
        {
            psi.ArgumentList.Add(args[i]);
        }

        using var proc = Process.Start(psi)!;
        var output = proc.StandardOutput.ReadToEnd();
        output += proc.StandardError.ReadToEnd();
        proc.WaitForExit();
        if (proc.ExitCode != 0 && !allowFailure)
        {
            throw new InvalidOperationException($"Command failed with exit {proc.ExitCode}: {output}");
        }
        return new ProcessResult(proc.ExitCode, output);
    }
    catch (Exception ex)
    {
        if (!allowFailure)
        {
            throw;
        }
        return new ProcessResult(-1, ex.ToString());
    }
}

sealed record HashRequest([property: JsonPropertyName("data_b64")] string DataBase64);
sealed record KeysetRequest([property: JsonPropertyName("name")] string? Name);
sealed record ProcessResult(int ExitCode, string Output);