using Avalonia.Controls;
using Avalonia.Interactivity;
using Avalonia.Platform.Storage;
using LehrerApp.Core.Importing;
using LehrerApp.Core.Interfaces;
using LehrerApp.Core.Models;
using LehrerApp.Core.Services;
using LehrerApp.Desktop.ViewModels.Groups;
using LehrerApp.Desktop.ViewModels.Students;
using LehrerApp.Desktop.Services;
using LehrerApp.Desktop.Views.Shared;
using LehrerApp.Desktop.Views.Students;
using Microsoft.Extensions.DependencyInjection;

namespace LehrerApp.Desktop.Views.Groups;

public partial class GroupDetailView : UserControl
{
    private const int MaximumImportFileSize = 20 * 1024 * 1024;

    public GroupDetailView() => InitializeComponent();

    protected override void OnDataContextChanged(EventArgs e)
    {
        base.OnDataContextChanged(e);
        if (DataContext is GroupDetailViewModel vm)
        {
            vm.OnAddStudent      = ShowAddStudentDialog;
            vm.OnWithdrawStudent = ShowWithdrawStudentDialog;
            vm.OnAddExam         = ShowAddExamDialog;
            vm.OnEditExam        = ShowEditExamDialog;
            vm.OnDuplicateExam   = ShowDuplicateExamDialog;
            vm.OnConfirmDeleteExam = ShowDeleteExamDialog;
            vm.OnGradeExam       = ShowGradeExamDialog;
            vm.OnEvaluateExam    = ShowEvaluateExamDialog;
            vm.OnConfirmReactivate = ShowReactivateConfirmDialog;
        }
    }

    private async Task<bool> ShowReactivateConfirmDialog()
    {
        var dialog = new ConfirmDialog
        {
            DataContext = new ConfirmDialogInfo
            {
                Title = "Archivierte Gruppe wieder aktivieren?",
                Message = "Nach der Wiederaktivierung können historische Daten dieser Gruppe wieder verändert werden.",
                ConfirmText = "Wieder aktivieren",
            },
        };
        var owner = TopLevel.GetTopLevel(this) as Window;
        return owner is not null && await dialog.ShowDialog<bool>(owner);
    }

    private async Task<bool> ShowAddStudentDialog()
    {
        if (DataContext is not GroupDetailViewModel vm || vm.Group is null) return false;

        var dialogVm = new AddStudentToGroupDialogViewModel(
            App.Services.GetRequiredService<IStudentRepository>(),
            App.Services.GetRequiredService<IGroupMembershipRepository>(),
            vm.Group.Id);

        var dialog = new AddStudentToGroupDialog { DataContext = dialogVm };
        var owner = TopLevel.GetTopLevel(this) as Window;
        if (owner is null) return false;

        return await dialog.ShowDialog<bool>(owner);
    }

    private async void OnImportParticipantsClick(object? sender, RoutedEventArgs e)
    {
        var owner = TopLevel.GetTopLevel(this) as Window;
        if (owner is null || DataContext is not GroupDetailViewModel vm || vm.Group is null) return;

        var service = App.Services.GetRequiredService<StudentImportService>();
        var patterns = service.SupportedExtensions.Select(extension => $"*{extension}").ToArray();
        var files = await owner.StorageProvider.OpenFilePickerAsync(new FilePickerOpenOptions
        {
            Title = $"Teilnehmer für {vm.Group.Name} importieren",
            AllowMultiple = false,
            FileTypeFilter =
            [
                new FilePickerFileType("Unterstützte Schülerlisten")
                {
                    Patterns = patterns.Length > 0 ? patterns : ["*.csv"],
                },
            ],
        });
        if (files.Count == 0) return;

        try
        {
            await using var source = await files[0].OpenReadAsync();
            if (source.CanSeek && source.Length > MaximumImportFileSize)
                throw new InvalidDataException("Die Importdatei ist größer als 20 MB.");

            using var buffer = new MemoryStream();
            await source.CopyToAsync(buffer);
            if (buffer.Length > MaximumImportFileSize)
                throw new InvalidDataException("Die Importdatei ist größer als 20 MB.");

            var importFile = new ImportFile(files[0].Name, buffer.ToArray());
            var preview = await Task.Run(async () =>
                await service.AnalyzeAsync(importFile, vm.Group.Id).ConfigureAwait(false));
            var dialogVm = new StudentImportDialogViewModel(service, preview, files[0].Name);
            var dialog = new StudentImportDialog { DataContext = dialogVm };
            if (!await dialog.ShowDialog<bool>(owner)) return;

            vm.LoadStudents();
            vm.ParticipationTab.RefreshCurrentGrid();
            var result = dialogVm.Result!;
            App.Services.GetRequiredService<NotificationService>().ShowSuccess(
                $"Teilnehmerimport abgeschlossen: {result.CreatedStudents} neu, "
                + $"{result.UpdatedStudents} ergänzt, {result.CreatedMemberships} zugeordnet.");
        }
        catch (Exception ex) when (ex is ImportFormatException
                                   or InvalidDataException
                                   or IOException
                                   or UnauthorizedAccessException)
        {
            App.Services.GetRequiredService<NotificationService>().ShowError(ex.Message);
        }
    }

    private async Task<bool> ShowWithdrawStudentDialog(StudentSummary student)
    {
        if (DataContext is not GroupDetailViewModel vm || vm.Group is null) return false;
        var memberships = App.Services.GetRequiredService<IGroupMembershipRepository>();
        var membership = memberships.GetByStudentAndGroup(student.Id, vm.Group.Id);
        if (membership is null) return false;

        var dialogVm = new WithdrawStudentDialogViewModel(
            memberships, membership, student.FullName, vm.Group.Name);
        var dialog = new WithdrawStudentDialog { DataContext = dialogVm };
        var owner = TopLevel.GetTopLevel(this) as Window;
        return owner is not null && await dialog.ShowDialog<bool>(owner);
    }

    private Task<bool> ShowAddExamDialog(Guid groupId) =>
        ShowExamDialog(groupId, editingExam: null, duplicateSource: null);

    private Task<bool> ShowEditExamDialog(Exam exam) =>
        ShowExamDialog(exam.GroupId, editingExam: exam, duplicateSource: null);

    private Task<bool> ShowDuplicateExamDialog(Exam exam) =>
        ShowExamDialog(exam.GroupId, editingExam: null, duplicateSource: exam);

    private async Task<bool> ShowExamDialog(Guid groupId, Exam? editingExam, Exam? duplicateSource)
    {
        if (DataContext is not GroupDetailViewModel vm || vm.Group is null) return false;

        var dialogVm = new ExamDialogViewModel(
            App.Services.GetRequiredService<IExamRepository>(),
            App.Services.GetRequiredService<ICompetencyDomainRepository>(),
            App.Services.GetRequiredService<IGradingKeyTemplateRepository>(),
            App.Services.GetRequiredService<GradingService>(),
            groupId, vm.Group.SubjectId, vm.Group.GradeLevel, vm.Group.GradingSystem,
            vm.SubjectName, vm.Group.IsDifferentiated, editingExam, duplicateSource);

        var dialog = new ExamDialog { DataContext = dialogVm };
        var owner = TopLevel.GetTopLevel(this) as Window;
        if (owner is null) return false;

        return await dialog.ShowDialog<bool>(owner);
    }

    private async Task<bool> ShowDeleteExamDialog(ExamSummary exam)
    {
        var dialog = new DeleteExamDialog { DataContext = exam.Title };
        var owner = TopLevel.GetTopLevel(this) as Window;
        return owner is not null && await dialog.ShowDialog<bool>(owner);
    }

    private async Task ShowGradeExamDialog(Exam exam)
    {
        if (DataContext is not GroupDetailViewModel vm || vm.Group is null) return;

        var dialogVm = new ExamGradingDialogViewModel(
            App.Services.GetRequiredService<IExamResultRepository>(),
            App.Services.GetRequiredService<IStudentRepository>(),
            App.Services.GetRequiredService<IGroupMembershipRepository>(),
            App.Services.GetRequiredService<GradingService>(),
            exam, vm.Group.Id);

        var dialog = new ExamGradingDialog { DataContext = dialogVm };
        var owner = TopLevel.GetTopLevel(this) as Window;
        if (owner is not null) await dialog.ShowDialog(owner);
    }

    private async Task ShowEvaluateExamDialog(Exam exam)
    {
        if (DataContext is not GroupDetailViewModel vm || vm.Group is null) return;

        var dialogVm = new ExamEvaluationDialogViewModel(
            App.Services.GetRequiredService<IExamRepository>(),
            App.Services.GetRequiredService<IExamResultRepository>(),
            App.Services.GetRequiredService<GradingService>(),
            exam, vm.Group.GradingSystem);

        var dialog = new ExamEvaluationDialog { DataContext = dialogVm };
        var owner = TopLevel.GetTopLevel(this) as Window;
        if (owner is not null) await dialog.ShowDialog(owner);
    }
}