using System.Collections;
using System.IO;
using System.Net;
using System.Net.Http;
using System.Text.Json;
using System.Windows;
using Lskj.AgentPet.Host.Core;
using Lskj.AgentPet.Host.Core.AstrBot;
using Lskj.AgentPet.Host.Core.Attachments;
using Lskj.AgentPet.Host.Core.Configuration;
using Lskj.AgentPet.Host.Core.ErpBridge;
using Lskj.AgentPet.Host.Core.Security;
using Lskj.AgentPet.Host.Core.WebViewHost;
using Microsoft.Win32;
using Microsoft.Web.WebView2.Core;

namespace Lskj.AgentPet.Host;

public partial class MainWindow : Window
{
    private const string TrustedPageUrl = EmbeddedPetResources.PageUrl;
    private const string SpriteResourceUrl = "https://lserp-sprite.local/atlas.webp";
    private const string PetContentSecurityPolicy =
        "default-src 'self'; img-src 'self' https://lserp-sprite.local data:; "
        + "style-src 'self'; script-src 'self'; connect-src 'none'; object-src 'none'; "
        + "base-uri 'none'; form-action 'none'; frame-src 'none'; child-src 'none'; "
        + "worker-src 'none'; media-src 'none'; manifest-src 'none'";
    private HostConfiguration? _configuration;
    private WebMessageCoordinator? _coordinator;
    private HttpClient? _httpClient;
    private readonly CancellationTokenSource _lifetime = new();
    private byte[]? _spriteBytes;
    private IReadOnlyDictionary<string, EmbeddedPetResource>? _petResources;
    private bool _closing;

    public MainWindow()
    {
        InitializeComponent();
        Loaded += OnLoaded;
        Closed += OnClosed;
    }

    private async void OnLoaded(object sender, RoutedEventArgs e)
    {
        try
        {
            Dictionary<string, string?> environment = EnvironmentValues();
            WindowsCredentialStore.PopulateAstrBotApiKey(environment);
            _configuration = HostConfiguration.Load(environment, AppContext.BaseDirectory);
            _spriteBytes = _configuration.ValidateFiles();
            _petResources = EmbeddedPetResources.Load();
            HttpClientHandler handler = new()
            {
                AllowAutoRedirect = false,
                AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate
            };
            _httpClient = new HttpClient(handler, disposeHandler: true);
            _coordinator = new WebMessageCoordinator(
                new SessionBoundErpBridgeClient(
                    new ErpBridgeClient(_configuration),
                    _configuration.ExpectedSessionScope),
                new AstrBotChatClient(_httpClient, _configuration),
                new WebViewSink(PetWebView),
                new PlanTrustStore(),
                _configuration.BridgeClientSessionId,
                new AttachmentSession(
                    new NativeAttachmentPicker(this),
                    new AstrBotAttachmentUploader(_httpClient, _configuration),
                    _configuration.MaximumAttachmentCount,
                    _configuration.MaximumAttachmentFileBytes,
                    _configuration.MaximumAttachmentTotalBytes));

            await PetWebView.EnsureCoreWebView2Async();
            ConfigureWebView(PetWebView.CoreWebView2);
            PositionAtBottomRight();
            PetWebView.Source = new Uri(TrustedPageUrl);
        }
        catch (HostError error)
        {
            MessageBox.Show(error.Message, "朗速 ERP 智能桌宠", MessageBoxButton.OK, MessageBoxImage.Error);
            Close();
        }
        catch (Exception)
        {
            MessageBox.Show(
                "桌宠启动失败，请联系管理员检查宿主日志和 WebView2 Runtime。",
                "朗速 ERP 智能桌宠",
                MessageBoxButton.OK,
                MessageBoxImage.Error);
            Close();
        }
    }

    private void ConfigureWebView(CoreWebView2 webView)
    {
        webView.Settings.AreDefaultContextMenusEnabled = false;
        webView.Settings.AreDevToolsEnabled = false;
        webView.Settings.AreHostObjectsAllowed = false;
        webView.Settings.IsPasswordAutosaveEnabled = false;
        webView.Settings.IsGeneralAutofillEnabled = false;
        webView.Settings.IsStatusBarEnabled = false;
        webView.Settings.IsZoomControlEnabled = false;
        webView.Settings.AreBrowserAcceleratorKeysEnabled = false;
        webView.Settings.IsNonClientRegionSupportEnabled = true;
        webView.AddWebResourceRequestedFilter(
            "https://lserp-pet.local/*",
            CoreWebView2WebResourceContext.All);
        webView.AddWebResourceRequestedFilter(
            "https://lserp-sprite.local/*",
            CoreWebView2WebResourceContext.All);
        webView.WebResourceRequested += OnPetResourceRequested;
        webView.WebResourceRequested += OnSpriteResourceRequested;
        webView.NavigationStarting += (_, args) =>
        {
            if (!string.Equals(args.Uri, TrustedPageUrl, StringComparison.OrdinalIgnoreCase))
                args.Cancel = true;
        };
        webView.NewWindowRequested += (_, args) => args.Handled = true;
        webView.WebMessageReceived += OnWebMessageReceived;
        webView.NavigationCompleted += (_, args) =>
        {
            if (!args.IsSuccess) return;
            webView.PostWebMessageAsJson(JsonSerializer.Serialize(new
            {
                type = "lserp.pet.configure",
                spriteUrl = SpriteResourceUrl
            }));
        };
    }

    private void OnPetResourceRequested(
        object? sender,
        CoreWebView2WebResourceRequestedEventArgs e)
    {
        if (sender is not CoreWebView2 webView
            || !e.Request.Uri.StartsWith(
                "https://lserp-pet.local/",
                StringComparison.Ordinal)) return;
        IReadOnlyDictionary<string, EmbeddedPetResource>? resources = _petResources;
        if (resources is not null
            && string.Equals(e.Request.Method, "GET", StringComparison.OrdinalIgnoreCase)
            && resources.TryGetValue(e.Request.Uri, out EmbeddedPetResource? resource))
        {
            MemoryStream content = new(
                resource.Bytes,
                0,
                resource.Bytes.Length,
                writable: false,
                publiclyVisible: false);
            string headers = "Content-Type: " + resource.ContentType + "\r\n"
                + "Content-Length: " + resource.Bytes.Length + "\r\n"
                + "Cache-Control: no-store\r\n"
                + "X-Content-Type-Options: nosniff\r\n"
                + "Cross-Origin-Resource-Policy: same-origin";
            if (resource.IsDocument)
                headers += "\r\nContent-Security-Policy: " + PetContentSecurityPolicy;
            e.Response = webView.Environment.CreateWebResourceResponse(
                content,
                200,
                "OK",
                headers);
            return;
        }

        e.Response = webView.Environment.CreateWebResourceResponse(
            new MemoryStream(Array.Empty<byte>(), writable: false),
            404,
            "Not Found",
            "Content-Length: 0\r\nCache-Control: no-store");
    }

    private void OnSpriteResourceRequested(
        object? sender,
        CoreWebView2WebResourceRequestedEventArgs e)
    {
        if (sender is not CoreWebView2 webView
            || !e.Request.Uri.StartsWith(
                "https://lserp-sprite.local/",
                StringComparison.Ordinal)) return;
        byte[]? sprite = _spriteBytes;
        if (sprite is not null
            && string.Equals(e.Request.Method, "GET", StringComparison.OrdinalIgnoreCase)
            && string.Equals(e.Request.Uri, SpriteResourceUrl, StringComparison.Ordinal))
        {
            MemoryStream content = new(
                sprite,
                0,
                sprite.Length,
                writable: false,
                publiclyVisible: false);
            string headers = "Content-Type: image/webp\r\n"
                + "Content-Length: " + sprite.Length + "\r\n"
                + "Cache-Control: no-store\r\n"
                + "X-Content-Type-Options: nosniff\r\n"
                + "Access-Control-Allow-Origin: https://lserp-pet.local\r\n"
                + "Cross-Origin-Resource-Policy: cross-origin";
            e.Response = webView.Environment.CreateWebResourceResponse(
                content,
                200,
                "OK",
                headers);
            return;
        }

        e.Response = webView.Environment.CreateWebResourceResponse(
            new MemoryStream(Array.Empty<byte>(), writable: false),
            404,
            "Not Found",
            "Content-Length: 0\r\nCache-Control: no-store");
    }

    private async void OnWebMessageReceived(object? sender, CoreWebView2WebMessageReceivedEventArgs e)
    {
        if (_coordinator is null
            || !string.Equals(e.Source, TrustedPageUrl, StringComparison.OrdinalIgnoreCase)) return;
        if (HostWindowCommandParser.TryParse(
            e.WebMessageAsJson,
            out HostWindowCommand windowCommand))
        {
            if (windowCommand == HostWindowCommand.Close) Close();
            return;
        }
        try
        {
            await _coordinator.HandleAsync(e.WebMessageAsJson, _lifetime.Token);
        }
        catch (OperationCanceledException) when (_closing)
        {
            return;
        }
        catch (HostError)
        {
            if (_closing) return;
            PetWebView.CoreWebView2.PostWebMessageAsJson(JsonSerializer.Serialize(new
            {
                type = "lserp.chat.error",
                code = "host_message_rejected",
                message = "桌宠消息被宿主安全策略拒绝。"
            }));
        }
        catch (Exception)
        {
            if (_closing) return;
            PetWebView.CoreWebView2.PostWebMessageAsJson(JsonSerializer.Serialize(new
            {
                type = "lserp.chat.error",
                code = "host_internal_error",
                message = "桌宠宿主发生内部错误。"
            }));
        }
    }

    private void PositionAtBottomRight()
    {
        Rect area = SystemParameters.WorkArea;
        Left = Math.Max(area.Left, area.Right - Width - 20);
        Top = Math.Max(area.Top, area.Bottom - Height - 20);
    }

    private void OnClosed(object? sender, EventArgs e)
    {
        _closing = true;
        _lifetime.Cancel();
        if (PetWebView.CoreWebView2 is not null)
        {
            PetWebView.CoreWebView2.WebMessageReceived -= OnWebMessageReceived;
            PetWebView.CoreWebView2.WebResourceRequested -= OnPetResourceRequested;
            PetWebView.CoreWebView2.WebResourceRequested -= OnSpriteResourceRequested;
        }
        _spriteBytes = null;
        _petResources = null;
        _httpClient?.Dispose();
        PetWebView.Dispose();
    }

    private static Dictionary<string, string?> EnvironmentValues()
    {
        Dictionary<string, string?> result = new(StringComparer.OrdinalIgnoreCase);
        foreach (DictionaryEntry item in Environment.GetEnvironmentVariables())
        {
            if (item.Key is string name) result[name] = item.Value?.ToString();
        }
        return result;
    }

    private sealed class WebViewSink : IWebViewSink
    {
        private readonly Microsoft.Web.WebView2.Wpf.WebView2CompositionControl _webView;

        public WebViewSink(Microsoft.Web.WebView2.Wpf.WebView2CompositionControl webView)
        {
            _webView = webView;
        }

        public async Task PostAsync(object message, CancellationToken cancellationToken = default)
        {
            string json = JsonSerializer.Serialize(message);
            await _webView.Dispatcher.InvokeAsync(() =>
                _webView.CoreWebView2.PostWebMessageAsJson(json),
                System.Windows.Threading.DispatcherPriority.Normal,
                cancellationToken);
        }
    }

    private sealed class NativeAttachmentPicker : IAttachmentPicker
    {
        private readonly Window _owner;

        public NativeAttachmentPicker(Window owner)
        {
            _owner = owner;
        }

        public async Task<IReadOnlyList<string>> PickAsync(
            int maximumCount,
            CancellationToken cancellationToken = default)
        {
            return await _owner.Dispatcher.InvokeAsync(() =>
            {
                cancellationToken.ThrowIfCancellationRequested();
                OpenFileDialog dialog = new()
                {
                    Title = "选择发票或业务明细",
                    CheckFileExists = true,
                    CheckPathExists = true,
                    Multiselect = true,
                    ValidateNames = true,
                    DereferenceLinks = false,
                    Filter = "支持的附件|*.png;*.jpg;*.jpeg;*.webp;*.pdf;*.xlsx;*.csv|"
                        + "图片|*.png;*.jpg;*.jpeg;*.webp|PDF|*.pdf|Excel/CSV|*.xlsx;*.csv"
                };
                if (dialog.ShowDialog(_owner) != true)
                    return (IReadOnlyList<string>)Array.Empty<string>();
                if (dialog.FileNames.Length > maximumCount)
                    throw new HostError(
                        "attachment_count_exceeded",
                        $"本次最多还可选择 {maximumCount} 个附件。");
                return dialog.FileNames.ToArray();
            }, System.Windows.Threading.DispatcherPriority.Normal, cancellationToken);
        }
    }
}