using System.Reflection;
using System.Text.RegularExpressions;
using Paca.App;
using Paca.Browser;
using Paca.Core.Config;

namespace Paca.Tests.Infrastructure;

/// <summary>
/// UI 유즈케이스 RED 스펙 테스트(docs/UI_USECASES.md)용 소스 접근 헬퍼.
/// 컴파일된 리소스가 아니라 저장소 원본 XAML·코드비하인드를 직접 읽어
/// "UI 복잡 버전" 계약(리소스 토큰·요소·설정 속성 존재)을 검증한다.
/// GREEN 전 단계이므로 대부분의 계약은 의도적으로 실패(RED)한다.
/// </summary>
public static class SourceTree
{
    /// <summary>저장소 루트(Paca.slnx 위치). 테스트 bin 에서 위로 올라가 탐색.</summary>
    public static string Root { get; } = FindRoot();

    private static string FindRoot()
    {
        for (var dir = new DirectoryInfo(AppContext.BaseDirectory); dir is not null; dir = dir.Parent)
        {
            if (File.Exists(Path.Combine(dir.FullName, "Paca.slnx")) || File.Exists(Path.Combine(dir.FullName, "VideoDownloader.slnx")))
                return dir.FullName;
        }
        throw new InvalidOperationException(
            $"솔루션 루트를 찾을 수 없습니다 (시작: {AppContext.BaseDirectory}). 빌드 산출물에서 실행 시 저장소 내 bin 디렉터리여야 합니다.");
    }

    public static string AppPath(string relative)
    {
        var srcPath = Path.Combine(Root, "src", "Paca.App", relative);
        if (File.Exists(srcPath) || Directory.Exists(srcPath)) return srcPath;
        return Path.Combine(Root, "Paca.App", relative);
    }
    public static bool AppFileExists(string relative) => File.Exists(AppPath(relative));
    public static bool DocFileExists(string fileName) => File.Exists(Path.Combine(Root, "docs", fileName));

    private static readonly Lazy<string> _mainWindowXaml = new(() => File.ReadAllText(AppPath("MainWindow.xaml")));
    private static readonly Lazy<string> _settingsXaml = new(() => File.ReadAllText(AppPath("SettingsWindow.xaml")));
    private static readonly Lazy<string> _sharedXaml = new(() => File.ReadAllText(AppPath("Themes/Shared.xaml")));
    private static readonly Lazy<string> _themeDark = new(() => File.ReadAllText(AppPath("Themes/Dark.xaml")));
    private static readonly Lazy<string> _themeLight = new(() => File.ReadAllText(AppPath("Themes/Light.xaml")));
    private static readonly Lazy<string> _mainWindowCs = new(() => File.ReadAllText(AppPath("MainWindow.xaml.cs")));
    private static readonly Lazy<string> _settingsCs = new(() => File.ReadAllText(AppPath("SettingsWindow.xaml.cs")));
    private static readonly Lazy<string> _readerModeCs = new(() => File.ReadAllText(AppPath("Browser/Features/ReaderMode.cs")));

    public static string MainWindowXaml => _mainWindowXaml.Value;
    public static string SettingsWindowXaml => _settingsXaml.Value;
    public static string SharedXaml => _sharedXaml.Value;
    public static string ThemeDarkXaml => _themeDark.Value;
    public static string ThemeLightXaml => _themeLight.Value;
    public static string MainWindowCs => _mainWindowCs.Value;
    public static string SettingsWindowCs => _settingsCs.Value;
    public static string ReaderModeCs => _readerModeCs.Value;

    /// <summary>XAML 리소스 사전에 키(x:Key)가 정의되어 있는지.</summary>
    public static bool HasKey(string xaml, string key) => xaml.Contains($"x:Key=\"{key}\"");

    /// <summary>SolidColorBrush 키의 색상(#RRGGBB) 조회. 없으면 null.</summary>
    public static string? BrushHex(string xaml, string key)
    {
        var m = Regex.Match(xaml, $"<SolidColorBrush\\s+x:Key=\"{Regex.Escape(key)}\"[^>]*Color=\"#([0-9A-Fa-f]{{6}})\"");
        return m.Success ? $"#{m.Groups[1].Value}" : null;
    }

    /// <summary>sys:Double 키의 숫자 값 조회. 없으면 null.</summary>
    public static double? GetDoubleResource(string xaml, string key)
    {
        var m = Regex.Match(xaml, $"<sys:Double\\s+x:Key=\"{Regex.Escape(key)}\">([0-9.]+)</sys:Double>");
        return m.Success && double.TryParse(m.Groups[1].Value, System.Globalization.CultureInfo.InvariantCulture, out var val) ? val : null;
    }

    /// <summary>WCAG 2.x 상대 휘도 기반 명도 대비율(1:1 ~ 21:1).</summary>
    public static double ContrastRatio(string hexA, string hexB)
    {
        var l1 = RelativeLuminance(hexA);
        var l2 = RelativeLuminance(hexB);
        return (Math.Max(l1, l2) + 0.05) / (Math.Min(l1, l2) + 0.05);
    }

    private static double RelativeLuminance(string hex)
    {
        double Channel(int offset) => Convert.ToInt32(hex.Substring(offset, 2), 16) / 255.0;
        static double Linearize(double c) => c <= 0.03928 ? c / 12.92 : Math.Pow((c + 0.055) / 1.055, 2.4);
        var r = Linearize(Channel(1));
        var g = Linearize(Channel(3));
        var b = Linearize(Channel(5));
        return 0.2126 * r + 0.7152 * g + 0.0722 * b;
    }

    /// <summary>Core·App·Browser 어셈블리에서 단순 이름으로 형식 탐색(아직 없는 신규 컴포넌트 계약용).</summary>
    public static Type? FindType(string simpleName)
    {
        foreach (var asm in TargetAssemblies())
        {
            Type[] types;
            try
            {
                types = asm.GetTypes();
            }
            catch (ReflectionTypeLoadException ex)
            {
                // 일부 형식 로드 실패는 건너뛰고 로드된 형식만 대상으로 한다.
                types = ex.Types.Where(t => t is not null).Select(t => t!).ToArray();
            }
            var found = types.FirstOrDefault(t => t.Name == simpleName);
            if (found is not null)
                return found;
        }
        return null;
    }

    private static IEnumerable<Assembly> TargetAssemblies()
    {
        yield return typeof(AppConfig).Assembly;
        yield return typeof(MainWindow).Assembly;
        yield return typeof(TabArchive).Assembly;
    }

    public static bool PropertyExists(Type type, string name) => UiContractPipeline.HasProperty(type, name);

    public static bool MethodExists(Type type, string name) => UiContractPipeline.HasMethod(type, name);

    /// <summary>유즈케이스 어설션 — 실패 메시지에 UC ID 와 사용자 스토리를 남긴다.</summary>
    public static void Usecase(bool ok, string id, string story) =>
        UiContractPipeline.AssertContract(ok, id, story);
}