using DataModel.Database.Common;
using Microsoft.Extensions.DependencyInjection;
using Timer = System.Timers.Timer;

namespace Processor;

public static class ExportProcessor
{
    private static readonly Timer EXPORT_TIMER = new();
    private static readonly SemaphoreSlim EXPORT_SEMAPHORE_BRICK_WALL = new(2);
    private static readonly SemaphoreSlim EXPORT_SEMAPHORE_EXPORTING = new(1);

    static ExportProcessor()
    {
        EXPORT_TIMER.Interval = 6_000; // 6 seconds
        EXPORT_TIMER.AutoReset = false;
        EXPORT_TIMER.Elapsed += async (sender, args) => await ExportToJson();
    }

    private static async Task ExportToJson()
    {
        if(!await EXPORT_SEMAPHORE_BRICK_WALL.WaitAsync(1))
            return;
        
        try
        {
            await EXPORT_SEMAPHORE_EXPORTING.WaitAsync();
            await using var db = ProcessorMeta.ServiceProvider.GetRequiredService<DataContext>();
            await db.ExportAsync(Environment.ExpandEnvironmentVariables(Path.Join(await AppSettings.GetAutoExportDestinationPath(), await AppSettings.GetAutoExportFilename())));
        }
        finally
        {
            EXPORT_SEMAPHORE_EXPORTING.Release();
            EXPORT_SEMAPHORE_BRICK_WALL.Release();
        }
    }
    
    public static async Task TriggerExport()
    {
        if (!await AppSettings.GetAutoExportEnabled())
            return;
        
        EXPORT_TIMER.Stop();
        EXPORT_TIMER.Start();
    }
}