using System;
using System.Diagnostics;
using System.IO;
using System.Linq;
using Gott.Extensions;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Routing;

namespace Gott.Endpoints;

public static class BackupEndpoint
{
    public static void MapBackupEndpoint(this IEndpointRouteBuilder app)
    {
        app.MapPost("/api/backup", HandleBackup);
    }

    private static async System.Threading.Tasks.Task<IResult> HandleBackup(HttpContext ctx)
    {
        if (!ctx.IsAdmin())
            return Results.Forbid();
        var dataDir = Path.Combine(AppContext.BaseDirectory, "data");

        if (!Directory.Exists(dataDir))
            return Results.NotFound(new { error = "Data-Ordner nicht gefunden" });

        var backupDir = Path.Combine(dataDir, "backup");
        Directory.CreateDirectory(backupDir);

        var timestamp = DateTimeOffset.UtcNow.ToUnixTimeSeconds();
        var archiveName = $"gott-{timestamp}.tar.gz";
        var archivePath = Path.Combine(backupDir, archiveName);

        var entries = Directory.GetFileSystemEntries(dataDir)
            .Select(e => Path.GetFileName(e))
            .Where(e => e != "backup")
            .ToArray();

        var psi = new ProcessStartInfo
        {
            FileName = "tar",
            RedirectStandardError = true,
            UseShellExecute = false
        };
        psi.ArgumentList.Add("-czf");
        psi.ArgumentList.Add(archivePath);
        psi.ArgumentList.Add("-C");
        psi.ArgumentList.Add(dataDir);
        foreach (var entry in entries)
            psi.ArgumentList.Add(entry);

        using (var process = Process.Start(psi))
        {
            if (process == null)
                return Results.StatusCode(500);

            var stderr = await process.StandardError.ReadToEndAsync();
            await process.WaitForExitAsync();

            if (process.ExitCode != 0)
                return Results.Problem($"tar fehlgeschlagen: {stderr}");
        }

        var bytes = await File.ReadAllBytesAsync(archivePath);
        return Results.File(bytes, "application/gzip", archiveName);
    }
}