using Microsoft.EntityFrameworkCore;

namespace Drab.Logic.Services;

public class OrderProcessor : IOrderProcessor
{
    private readonly ILogger<OrderProcessor> _logger;
    private readonly IServiceScopeFactory _serviceScopeFactory;
    private readonly IPrintService _printService;
    private readonly IOrderPdfGenerator _orderPdfGenerator;
    private readonly OrderEventBus _eventBus;

    public OrderProcessor(IServiceScopeFactory serviceScopeFactory,
                          IPrintService printService,
                          IOrderPdfGenerator orderPdfGenerator,
                          OrderEventBus eventBus, ILogger<OrderProcessor> logger)
    {
        _serviceScopeFactory = serviceScopeFactory;
        _printService = printService;
        _orderPdfGenerator = orderPdfGenerator;
        _eventBus = eventBus;
        _logger = logger;
    }

    public async Task ProcessOrder(DokDto order)
    {
        var dok = await GetOrCreateOrder(order);

        if (dok.IsPrinted)
            return;

        var filePath = await EnsureOrderPdfExists(order, dok);
        var printResult = await PrintOrder(order, filePath);

        if (printResult.IsSuccess)
        {
            dok.IsPrinted = true;
            await SaveOrderIfChanged(dok);
        }
    }

    private async Task<OrderDb> GetOrCreateOrder(DokDto order)
    {
        var dok = await GetOrder(order.DokId);

        if (dok != null)
            return dok;

        _logger.LogInformation("Creating new order - {OrderNo}", order.NrDok);

        dok = new OrderDb
        {
            DokId = order.DokId,
            Created = order.Data,
            OrderId = order.DokId,
            Filename = string.Empty,
            IsPrinted = false,
            Shop = order.Sklep,
            OrderNumber = order.NrDok
        };

        await SaveOrderIfChanged(dok);
        return dok;
    }

    private async Task<string> EnsureOrderPdfExists(DokDto order, OrderDb dok)
    {
        if (!string.IsNullOrEmpty(dok.Filename))
        {
            var fullPath = Path.Combine(Constants.ReportsOutputPath, dok.Filename);
            if (File.Exists(fullPath))
                return fullPath;
        }

        _logger.LogInformation("Generating order file: {OrderNo}", order.NrDok);

        var generatedFilename = await _orderPdfGenerator.GenerateOrder(order);
        var newPath = Path.Combine(Constants.ReportsOutputPath, generatedFilename);

        if (string.Equals(dok.Filename, generatedFilename, StringComparison.OrdinalIgnoreCase))
            return newPath;
        dok.Filename = generatedFilename;
        await SaveOrderIfChanged(dok);

        return newPath;
    }

    private async Task<PrintDocumentResult> PrintOrder(DokDto order, string filePath)
    {
        _logger.LogInformation("Printing order: {OrderNo}", order.NrDok);

        var result = await _printService.PrintPdf(new PrintDocumentRequest(filePath, order.DokId));

        _logger.LogInformation("Printing result - OrderNo: {OrderNo}, Success: {IsSuccess}, Message: {Message}",
            order.NrDok, result.IsSuccess, result.Message);

        return result;
    }

    private async Task<OrderDb?> GetOrder(long dokId)
    {
        try
        {
            using var scope = _serviceScopeFactory.CreateScope();
            var context = scope.ServiceProvider.GetRequiredService<LocalDbContext>();

            return await context.Orders
                .FirstOrDefaultAsync(x => x.DokId == dokId);
        }
        catch (Exception e)
        {
            _logger.LogError(e, "Error retrieving order from database");
            return null;
        }
    }

    private async Task SaveOrderIfChanged(OrderDb order)
    {
        using var scope = _serviceScopeFactory.CreateScope();
        var context = scope.ServiceProvider.GetRequiredService<LocalDbContext>();

        var existing = await context.Orders.FirstOrDefaultAsync(x => x.DokId == order.DokId);

        if (existing == null)
        {
            await context.Orders.AddAsync(order);
            await context.SaveChangesAsync();
            _eventBus.NotifyOrdersChanged();
            return;
        }

        if (existing.IsPrinted == order.IsPrinted && existing.Filename == order.Filename)
            return;

        existing.IsPrinted = order.IsPrinted;
        existing.Filename = order.Filename;

        context.Orders.Update(existing);
        await context.SaveChangesAsync();

        _eventBus.NotifyOrdersChanged();
    }
}