using System.Collections.ObjectModel;
using CloudPrint.Client.Infrastructure;
using CloudPrint.Client.Models;
using CloudPrint.Client.Services;
using CloudPrint.Client.Services.Abstractions;
using Microsoft.Win32;

namespace CloudPrint.Client.ViewModels;

public sealed class LibraryViewModel : ObservableObject
{
    private readonly IFileService _fileService;
    private readonly IPrintBackendClient _backendClient;
    private readonly ClientSettings _settings;
    private LibraryCategory? _selectedCategory;
    private CloudPrintDocument? _selectedDocument;
    private string _statusMessage = "文库就绪";

    public LibraryViewModel()
        : this(new FileService(), new GrpcService(), new ClientSettings())
    {
    }

    public LibraryViewModel(IFileService fileService, IPrintBackendClient backendClient, ClientSettings settings)
    {
        _fileService = fileService;
        _backendClient = backendClient;
        _settings = settings;

        Categories.Add(new LibraryCategory { Id = 1, Name = "教材资料", Icon = "📘", SortOrder = 1 });
        Categories.Add(new LibraryCategory { Id = 2, Name = "考试真题", Icon = "📝", SortOrder = 2 });
        Categories.Add(new LibraryCategory { Id = 3, Name = "证件照片", Icon = "🖼️", SortOrder = 3 });
        Categories.Add(new LibraryCategory { Id = 4, Name = "其他文件", Icon = "📁", SortOrder = 99 });

        SelectedCategory = Categories.FirstOrDefault();
        AddDocumentCommand = new RelayCommand(AddDocument);
        RemoveDocumentCommand = new RelayCommand(RemoveSelectedDocument, () => SelectedDocument is not null);
        SyncSelectedCommand = new AsyncRelayCommand(SyncSelectedAsync, () => SelectedDocument is not null && _backendClient.IsConnected);
        SyncAllCommand = new AsyncRelayCommand(SyncAllAsync, () => Documents.Any(document => !document.IsUploaded) && _backendClient.IsConnected);
    }

    public ObservableCollection<LibraryCategory> Categories { get; } = new();
    public ObservableCollection<CloudPrintDocument> Documents { get; } = new();

    public LibraryCategory? SelectedCategory
    {
        get => _selectedCategory;
        set => SetProperty(ref _selectedCategory, value);
    }

    public CloudPrintDocument? SelectedDocument
    {
        get => _selectedDocument;
        set
        {
            if (SetProperty(ref _selectedDocument, value))
            {
                RemoveDocumentCommand.RaiseCanExecuteChanged();
                SyncSelectedCommand.RaiseCanExecuteChanged();
            }
        }
    }

    public string StatusMessage
    {
        get => _statusMessage;
        private set => SetProperty(ref _statusMessage, value);
    }

    public RelayCommand AddDocumentCommand { get; }
    public RelayCommand RemoveDocumentCommand { get; }
    public AsyncRelayCommand SyncSelectedCommand { get; }
    public AsyncRelayCommand SyncAllCommand { get; }

    public void RefreshCommandState()
    {
        SyncSelectedCommand.RaiseCanExecuteChanged();
        SyncAllCommand.RaiseCanExecuteChanged();
    }

    private void AddDocument()
    {
        var dialog = new Microsoft.Win32.OpenFileDialog
        {
            Title = "选择要加入文库的文件",
            Multiselect = true,
            Filter = "支持的文件|*.pdf;*.doc;*.docx;*.txt;*.xls;*.xlsx;*.ppt;*.pptx;*.jpg;*.jpeg;*.png;*.bmp;*.gif;*.zip;*.rar|所有文件|*.*"
        };

        if (dialog.ShowDialog() != true)
        {
            return;
        }

        var addedCount = 0;
        var categoryName = SelectedCategory?.Name ?? "未分类";
        var limit = Math.Max(1, _settings.MaxUploadSizeMb) * 1024L * 1024L;

        foreach (var fileName in dialog.FileNames)
        {
            var validation = _fileService.ValidateFile(fileName, limit);
            if (!validation.IsValid)
            {
                StatusMessage = $"跳过 {System.IO.Path.GetFileName(fileName)}：{validation.Message}";
                continue;
            }

            var document = _fileService.CopyToLibrary(fileName, _settings.LibraryRoot, categoryName, SelectedCategory?.Id ?? 0);
            Documents.Insert(0, document);
            addedCount++;
        }

        StatusMessage = addedCount > 0 ? $"已加入 {addedCount} 个文件到文库" : "没有文件被加入文库";
        RefreshCommandState();
    }

    private void RemoveSelectedDocument()
    {
        if (SelectedDocument is null)
        {
            return;
        }

        var document = SelectedDocument;
        Documents.Remove(document);
        SelectedDocument = null;
        StatusMessage = $"已从列表移除：{document.Title}";
        RefreshCommandState();
    }

    private async Task SyncSelectedAsync()
    {
        if (SelectedDocument is null)
        {
            return;
        }

        await _backendClient.UploadLibraryDocumentAsync(SelectedDocument).ConfigureAwait(true);
        StatusMessage = $"已同步：{SelectedDocument.Title}";
        RefreshCommandState();
    }

    private async Task SyncAllAsync()
    {
        var pendingDocuments = Documents.Where(document => !document.IsUploaded).ToList();
        foreach (var document in pendingDocuments)
        {
            await _backendClient.UploadLibraryDocumentAsync(document).ConfigureAwait(true);
        }

        StatusMessage = $"已同步 {pendingDocuments.Count} 个文库文件";
        RefreshCommandState();
    }
}