using System.IO;
using System.Text.RegularExpressions;
using System.Xml.Linq;
using Xunit;

namespace MmdPdf.Tests;

public sealed class LocalizationParityTests
{
    private static readonly string StringsDirectory = FindStringsDirectory();
    private static readonly XNamespace Xaml = "http://schemas.microsoft.com/winfx/2006/xaml";

    [Fact]
    public void EveryLocaleHasTheEnglishKeysAndPlaceholders()
    {
        var english = ReadStrings(Path.Combine(StringsDirectory, "en-US.xaml"));
        foreach (var file in Directory.GetFiles(StringsDirectory, "*.xaml"))
        {
            var localized = ReadStrings(file);
            Assert.True(english.Keys.OrderBy(x => x).SequenceEqual(localized.Keys.OrderBy(x => x)),
                $"{Path.GetFileName(file)} does not contain exactly the English resource-key set.");

            foreach (var key in english.Keys)
            {
                Assert.False(string.IsNullOrWhiteSpace(localized[key]),
                    $"{Path.GetFileName(file)} has an empty value for {key}.");
                Assert.True(Placeholders(english[key]).SequenceEqual(Placeholders(localized[key])),
                    $"{Path.GetFileName(file)} has different placeholders for {key}.");
            }
        }
    }

    [Fact]
    public void Issue227SharedSurfacesHaveResourceKeys()
    {
        var english = ReadStrings(Path.Combine(StringsDirectory, "en-US.xaml"));
        string[] required =
        [
            "Str_Btn_OK", "Str_Btn_Yes", "Str_Btn_No", "Str_Btn_Cancel",
            "Str_RecentMissing",
            "Str_St_CopiedAnnotationOne", "Str_St_CopiedAnnotationMany",
            "Str_St_PastedAnnotationOne", "Str_St_PastedAnnotationMany",
            "Str_St_DeletedAnnotationOne", "Str_St_DeletedAnnotationMany",
            "Str_Search_NoMatches", "Str_Search_Error", "Str_Search_Summary",
            "Str_Search_PreviousTT", "Str_Search_NextTT", "Str_Search_CloseTT",
            "Str_Busy_FlattenPage", "Str_Busy_ExportPage", "Str_Busy_CancelHint",
            "Str_Busy_DownloadingMany"
        ];

        foreach (string key in required)
            Assert.True(english.ContainsKey(key), $"Missing #227 resource key: {key}");
    }

    [Fact]
    public void Issue227ReportedEnglishIsNotHardcodedInItsUiPaths()
    {
        string root = Directory.GetParent(StringsDirectory)!.FullName;
        var checks = new Dictionary<string, string[]>
        {
            ["Controls/KillerDialog.cs"] = ["MakeBtn(\"Yes\"", "MakeBtn(\"No\"", "MakeBtn(\"Cancel\""],
            ["Shell/FileOperations.cs"] = [": \"missing\"", "\"Exporting\"", "\"Flattening\""],
            ["Shell/ContextMenu.cs"] = ["Copied 1 annotation", "Pasted 1 annotation"],
            ["Controls/Viewer/PdfViewer.Annotations.cs"] = ["Deleted selected annotation"],
            ["Shell/Search.cs"] = ["Previous Match (Shift+Enter)", "Next Match (Enter)", "Close (Esc)"],
            ["Features/Search/SearchController.cs"] = ["SetResultText(\"No matches\")", "SetResultText(\"Search error\")"],
            ["Services/OcrLanguages.cs"] = ["(Esc to cancel)"]
        };

        foreach (var check in checks)
        {
            string source = File.ReadAllText(Path.Combine(root, check.Key.Replace('/', Path.DirectorySeparatorChar)));
            foreach (string text in check.Value)
                Assert.DoesNotContain(text, source);
        }
    }

    private static Dictionary<string, string> ReadStrings(string path) =>
        XDocument.Load(path).Root!.Elements()
            .Where(e => e.Attribute(Xaml + "Key") is not null)
            .ToDictionary(e => e.Attribute(Xaml + "Key")!.Value, e => e.Value);

    private static IEnumerable<string> Placeholders(string value) =>
        Regex.Matches(value, @"\{\d+(?::[^}]*)?\}").Cast<Match>().Select(m => m.Value).OrderBy(x => x);

    private static string FindStringsDirectory()
    {
        var directory = new DirectoryInfo(AppContext.BaseDirectory);
        while (directory is not null && !Directory.Exists(Path.Combine(directory.FullName, "Strings")))
            directory = directory.Parent;
        Assert.NotNull(directory);
        return Path.Combine(directory!.FullName, "Strings");
    }
}