refactor(3): VideoDownloader.Browser library - tabs/find/search-engine/zoom/bookmark-history stores extracted from App (66 GREEN)

VideoDownloader.Browser/BrowserModels.cs

@@ -0,0 +1,5 @@
+namespace VideoDownloader.Browser;
+
+public record Bookmark(string Title, string Url);
+
+public record HistoryEntry(string Title, string Url, DateTime VisitedAt);

VideoDownloader.Browser/BrowserStore.cs

@@ -0,0 +1,67 @@
+using System.Text.Json;
+
+namespace VideoDownloader.Browser;
+
+/// <summary>즐겨찾기/히스토리 JSON 영속화 (%AppData%/VideoDownloader).
+/// #5 저장/로드 실패를 조용 삼킴하지 않고 browserstore.log 에 기록하며,
+///    손상 파일은 백업 후 빈 목록을 반환(다음 저장이 원본을 덮어쓰는 데이터 손실 방지).</summary>
+public static class BrowserStore
+{
+    private static string Dir => VideoDownloader.Core.Platform.CorePaths.DataDir;
+    private static string BookmarksPath => Path.Combine(Dir, "bookmarks.json");
+    private static string HistoryPath => Path.Combine(Dir, "history.json");
+    private static readonly JsonSerializerOptions JsonOpts = new() { WriteIndented = true };
+
+    public static List<Bookmark> LoadBookmarks()
+    {
+        try { if (File.Exists(BookmarksPath)) return JsonSerializer.Deserialize<List<Bookmark>>(File.ReadAllText(BookmarksPath)) ?? new(); }
+        catch (Exception e) { LogLoadFail(BookmarksPath, e); }
+        return new();
+    }
+
+    public static void SaveBookmarks(List<Bookmark> bookmarks)
+    {
+        try { Directory.CreateDirectory(Dir); File.WriteAllText(BookmarksPath, JsonSerializer.Serialize(bookmarks, JsonOpts)); }
+        catch (Exception e) { LogFail("저장", BookmarksPath, e); } // 디스크 가득/권한/잠금 → UI 스레드 전파 대신 로그
+    }
+
+    public static List<HistoryEntry> LoadHistory()
+    {
+        try { if (File.Exists(HistoryPath)) return JsonSerializer.Deserialize<List<HistoryEntry>>(File.ReadAllText(HistoryPath)) ?? new(); }
+        catch (Exception e) { LogLoadFail(HistoryPath, e); }
+        return new();
+    }
+
+    public static void SaveHistory(List<HistoryEntry> history)
+    {
+        try { Directory.CreateDirectory(Dir); File.WriteAllText(HistoryPath, JsonSerializer.Serialize(history, JsonOpts)); }
+        catch (Exception e) { LogFail("저장", HistoryPath, e); }
+    }
+
+    /// <summary>로드 실패(손상/권한/잠금) 시 원본을 .corrupt 백업한 뒤 로그.
+    /// 빈 목록을 반환하더라도 원본이 남아 다음 저장이 사용자 데이터를 덮어쓰지 않게 한다.</summary>
+    private static void LogLoadFail(string path, Exception e)
+    {
+        try
+        {
+            if (File.Exists(path))
+                File.Move(path, $"{path}.corrupt.{DateTime.Now:yyyyMMddHHmmss}.bak", overwrite: true);
+        }
+        catch { /* best-effort 백업 — 실패해도 계속 진행 */ }
+        LogFail("로드", path, e);
+    }
+
+    private static void LogFail(string op, string path, Exception e)
+        => Log($"{op} 실패({Path.GetFileName(path)}): {e.GetType().Name}: {e.Message}");
+
+    private static void Log(string msg)
+    {
+        try
+        {
+            Directory.CreateDirectory(Dir);
+            File.AppendAllText(Path.Combine(Dir, "browserstore.log"),
+                $"[{DateTime.Now:yyyy-MM-dd HH:mm:ss}] {msg}{Environment.NewLine}");
+        }
+        catch { /* 로그마저 실패하면 조용히 */ }
+    }
+}

VideoDownloader.Browser/FindSession.cs

@@ -0,0 +1,126 @@
+using Microsoft.Web.WebView2.Core;
+
+namespace VideoDownloader.Browser;
+
+/// <summary>네이티브 Find API 의 최소 추상화(단위 테스트용 fake 교체 가능).</summary>
+public interface IFindApi
+{
+    Task StartAsync(string term, bool caseSensitive, bool matchWord, bool highlightAll);
+    void FindNext();
+    void FindPrevious();
+    void Stop();
+    event EventHandler<int>? MatchCountChanged;
+    event EventHandler<int>? ActiveMatchIndexChanged;
+}
+
+/// <summary>WebView2 네이티브 Find(CoreWebView2.Find) 를 IFindApi 로 감싼 어댑터.
+/// 옵션 객체는 public ctor 가 없어 CoreWebView2Environment.CreateFindOptions() 로 생성.</summary>
+public sealed class WebView2FindApi : IFindApi
+{
+    private readonly CoreWebView2 _cv;
+    private readonly CoreWebView2Environment _env;
+
+    public WebView2FindApi(CoreWebView2 cv, CoreWebView2Environment env)
+    {
+        _cv = cv;
+        _env = env;
+    }
+
+    public Task StartAsync(string term, bool caseSensitive, bool matchWord, bool highlightAll)
+    {
+        var o = _env.CreateFindOptions();
+        o.FindTerm = term;
+        o.IsCaseSensitive = caseSensitive;
+        o.ShouldMatchWord = matchWord;
+        o.ShouldHighlightAllMatches = highlightAll;
+        o.SuppressDefaultFindDialog = true; // 자체 WPF 검색 바 사용
+        return _cv.Find.StartAsync(o);
+    }
+
+    public void FindNext() => _cv.Find.FindNext();
+    public void FindPrevious() => _cv.Find.FindPrevious();
+    public void Stop() => _cv.Find.Stop();
+
+    // 이벤트 인자가 object 로 전달되므로 매치 수는 Find 프로퍼티에서 직접 읽는다.
+    public event EventHandler<int>? MatchCountChanged
+    {
+        add => _cv.Find.MatchCountChanged += (s, _) => value?.Invoke(s, _cv.Find.MatchCount);
+        remove { }
+    }
+
+    public event EventHandler<int>? ActiveMatchIndexChanged
+    {
+        add => _cv.Find.ActiveMatchIndexChanged += (s, _) => value?.Invoke(s, _cv.Find.ActiveMatchIndex);
+        remove { }
+    }
+}
+
+/// <summary>
+/// 페이지 내 검색 세션 상태 머신(T1-3). 용어·매치 수·활성 인덱스를 유지하고
+/// UI(검색 바)가 표시할 "3 / 17" 텍스트를 제공한다.
+/// </summary>
+public sealed class FindSession : IDisposable
+{
+    private readonly IFindApi _api;
+
+    public string Term { get; private set; } = string.Empty;
+    public int MatchCount { get; private set; }
+    public int ActiveMatchIndex { get; private set; }
+    public bool IsCaseSensitive { get; private set; }
+    public bool MatchWholeWord { get; private set; }
+
+    public event Action? StateChanged;
+
+    public FindSession(IFindApi api)
+    {
+        _api = api;
+        _api.MatchCountChanged += (_, n) => { MatchCount = n; StateChanged?.Invoke(); };
+        _api.ActiveMatchIndexChanged += (_, n) => { ActiveMatchIndex = n; StateChanged?.Invoke(); };
+    }
+
+    public string StatusText
+    {
+        get
+        {
+            if (MatchCount <= 0) return "결과 없음";
+            var oneBased = ActiveMatchIndex >= 0 ? ActiveMatchIndex + 1 : 0;
+            return $"{oneBased} / {MatchCount}";
+        }
+    }
+
+    public async Task StartAsync(string term)
+    {
+        Term = term ?? "";
+        if (string.IsNullOrWhiteSpace(term))
+        {
+            Close();
+            return;
+        }
+        MatchCount = 0;
+        ActiveMatchIndex = -1;
+        await _api.StartAsync(Term, IsCaseSensitive, MatchWholeWord, highlightAll: true);
+        StateChanged?.Invoke();
+    }
+
+    public void SetOptions(bool caseSensitive, bool matchWholeWord)
+    {
+        IsCaseSensitive = caseSensitive;
+        MatchWholeWord = matchWholeWord;
+        if (!string.IsNullOrWhiteSpace(Term))
+            _ = StartAsync(Term); // 옵션 변경은 재시작 필요(네이티브 제약)
+    }
+
+    public void Next() => _api.FindNext();
+    public void Previous() => _api.FindPrevious();
+
+    public void Close()
+    {
+        _api.Stop();
+        Term = string.Empty;
+        MatchCount = 0;
+        ActiveMatchIndex = -1;
+        StateChanged?.Invoke();
+    }
+
+    public void Dispose() => Close();
+}

VideoDownloader.Browser/SearchEngine.cs

@@ -0,0 +1,34 @@
+namespace VideoDownloader.Browser;
+
+/// <summary>검색엔진 정의. QueryTemplate 의 {0} 이 URL 인코딩된 검색어로 치환된다.</summary>
+public sealed record SearchEngine(string Name, string Keyword, string QueryTemplate);
+
+/// <summary>기본 프리셋 엔진. Keyword 는 주소창에서 `&lt;키워드&gt; &lt;검색어&gt;` 형태로 즉시 전환에 쓰인다.</summary>
+public static class SearchEngines
+{
+    public static readonly IReadOnlyList<SearchEngine> Presets = new[]
+    {
+        new SearchEngine("Google",     "g",  "https://www.google.com/search?q={0}"),
+        new SearchEngine("Bing",       "b",  "https://www.bing.com/search?q={0}"),
+        new SearchEngine("DuckDuckGo", "d",  "https://duckduckgo.com/?q={0}"),
+        new SearchEngine("Naver",      "n",  "https://search.naver.com/search.naver?query={0}"),
+        new SearchEngine("YouTube",    "yt", "https://www.youtube.com/results?search_query={0}"),
+    };
+
+    public static SearchEngine? FindByName(string? name, IEnumerable<SearchEngine>? extra = null)
+    {
+        var pool = extra != null ? Presets.Concat(extra) : Presets;
+        return pool.FirstOrDefault(e =>
+            string.Equals(e.Name, name, StringComparison.OrdinalIgnoreCase));
+    }
+
+    public static SearchEngine? FindByKeyword(string? keyword, IEnumerable<SearchEngine>? extra = null)
+    {
+        var pool = extra != null ? Presets.Concat(extra) : Presets;
+        return pool.FirstOrDefault(e =>
+            string.Equals(e.Keyword, keyword, StringComparison.OrdinalIgnoreCase));
+    }
+}
+
+/// <summary>주소창 입력에 대한 네비게이션 의도. IsUrl=false 면 Target 은 검색 결과 URL.</summary>
+public sealed record NavigationIntent(bool IsUrl, string Target, string? EngineName = null);

VideoDownloader.Browser/SearchEngineResolver.cs

@@ -0,0 +1,80 @@
+using System.Text.RegularExpressions;
+
+namespace VideoDownloader.Browser;
+
+/// <summary>
+/// 주소창 입력을 URL 또는 검색 의도로 판별한다(T1-4).
+/// 판별 순서: ① 명시적 스킴 ② localhost/IPv4 ③ 도메인 형태 ④ 키워드 접두(`g `, `yt `) ⑤ 기본 엔진 검색.
+/// </summary>
+public sealed partial class SearchEngineResolver
+{
+    private readonly SearchEngine _default;
+    private readonly List<SearchEngine> _custom;
+
+    public SearchEngineResolver(string defaultEngineName, IEnumerable<SearchEngine>? customEngines = null)
+    {
+        _default = SearchEngines.FindByName(defaultEngineName, customEngines)
+                    ?? SearchEngines.Presets[0];
+        _custom = customEngines?.ToList() ?? new();
+    }
+
+    public SearchEngine DefaultEngine => _default;
+
+    /// <summary>입력이 비었으면 null, URL 이면 URL 의도, 아니면 검색 결과 URL 의도.</summary>
+    public NavigationIntent? Resolve(string? input)
+    {
+        input = input?.Trim();
+        if (string.IsNullOrEmpty(input)) return null;
+
+        if (HasScheme(input))
+            return new NavigationIntent(true, input);
+
+        if (IsLocalHost(input) || IsIpv4(input))
+            return new NavigationIntent(true, "https://" + input);
+
+        if (LooksLikeDomain(input))
+            return new NavigationIntent(true, "https://" + input);
+
+        // 키워드 전환: "g 고양이" → Google 검색. 미등록 키워드는 검색어의 일부.
+        if (MatchKeyword(input) is { } kw)
+            return new NavigationIntent(false, Format(kw.engine, kw.query), kw.engine.Name);
+
+        return new NavigationIntent(false, Format(_default, input), _default.Name);
+    }
+
+    private static string Format(SearchEngine engine, string query)
+        => string.Format(engine.QueryTemplate, Uri.EscapeDataString(query).Replace("%20", "+"));
+
+    private (SearchEngine engine, string query)? MatchKeyword(string input)
+    {
+        var m = KeywordPrefix().Match(input);
+        if (!m.Success) return null;
+        var engine = SearchEngines.FindByKeyword(m.Groups[1].Value, _custom);
+        return engine == null ? null : (engine, m.Groups[2].Value);
+    }
+
+    private static bool HasScheme(string s) =>
+        s.StartsWith("http://", StringComparison.OrdinalIgnoreCase)
+        || s.StartsWith("https://", StringComparison.OrdinalIgnoreCase)
+        || s.StartsWith("file://", StringComparison.OrdinalIgnoreCase)
+        || s.StartsWith("about:", StringComparison.OrdinalIgnoreCase)
+        || s.StartsWith("data:", StringComparison.OrdinalIgnoreCase)
+        || s.StartsWith("blob:", StringComparison.OrdinalIgnoreCase);
+
+    private static bool IsLocalHost(string s) =>
+        s.Equals("localhost", StringComparison.OrdinalIgnoreCase)
+        || s.StartsWith("localhost:", StringComparison.OrdinalIgnoreCase);
+
+    private static bool IsIpv4(string s) =>
+        s.Length > 7 && s[0] >= '0' && s[0] <= '9' && Regex.IsMatch(s, @"^\d{1,3}(\.\d{1,3}){3}(:\d+)?([/?#].*)?$");
+
+    private static bool LooksLikeDomain(string s) =>
+        DomainPattern().IsMatch(s);
+
+    // 라벨.라벨[.라벨...] 형태(최소 점 1개) + 선택적 포트/경로. 공백 포함 시 불일치.
+    [GeneratedRegex(@"^[a-zA-Z0-9]([a-zA-Z0-9\-]*[a-zA-Z0-9])?(\.[a-zA-Z0-9]([a-zA-Z0-9\-]*[a-zA-Z0-9])?)+(:\d+)?([/?#].*)?$")]
+    private static partial Regex DomainPattern();
+
+    [GeneratedRegex(@"^(\S+)\s+(.+)$", RegexOptions.Singleline)]
+    private static partial Regex KeywordPrefix();
+}

VideoDownloader.Browser/SiteZoomStore.cs

@@ -0,0 +1,106 @@
+using System.IO;
+using System.Text.Json;
+
+namespace VideoDownloader.Browser;
+
+/// <summary>
+/// 사이트별 줌 배율 영속 저장소(T1-7). WebView2 는 사이트별 줌 영속을 보장하지 않아
+/// 앱이 도메인→배율 사전을 SSOT 로 관리한다. LRU 300개, 저장 즉시 원자적 파일 기록.
+/// </summary>
+public sealed class SiteZoomStore
+{
+    private sealed record Entry(double Zoom, long LastUsedTicks);
+
+    private const int MaxEntries = 300;
+    private const double Min = 0.1, Max = 5.0;
+
+    private readonly string _path;
+    private readonly object _lock = new();
+    private readonly Dictionary<string, Entry> _map = new(StringComparer.OrdinalIgnoreCase);
+
+    public SiteZoomStore(string path)
+    {
+        _path = path;
+        try
+        {
+            if (File.Exists(path))
+            {
+                var loaded = JsonSerializer.Deserialize<Dictionary<string, Entry>>(File.ReadAllText(path));
+                if (loaded != null)
+                    foreach (var (k, v) in loaded) _map[k] = v;
+            }
+        }
+        catch
+        {
+            // 손상된 JSON → 빈 상태로 시작(기존 BrowserStore 정책과 동일)
+            _map.Clear();
+        }
+    }
+
+    public int Count { get { lock (_lock) return _map.Count; } }
+
+    /// <summary>URL 의 호스트에 저장된 배율. 없으면 1.0. 읽기는 LRU 를 갱신한다.</summary>
+    public double Get(string? url)
+    {
+        var host = NormalizeHost(url);
+        if (host == null) return 1.0;
+        lock (_lock)
+        {
+            if (_map.TryGetValue(host, out var e))
+            {
+                _map[host] = e with { LastUsedTicks = DateTime.UtcNow.Ticks };
+                return e.Zoom;
+            }
+        }
+        return 1.0;
+    }
+
+    /// <summary>배율 저장(0.1~5.0 클램프). 초과분은 가장 오래된 사용 순으로 제거 후 즉시 영속.</summary>
+    public void Set(string? url, double zoom)
+    {
+        var host = NormalizeHost(url);
+        if (host == null) return;
+        zoom = Math.Clamp(zoom, Min, Max);
+        lock (_lock)
+        {
+            _map[host] = new Entry(zoom, DateTime.UtcNow.Ticks);
+            if (_map.Count > MaxEntries)
+                foreach (var k in _map.OrderBy(kv => kv.Value.LastUsedTicks).Take(_map.Count - MaxEntries).Select(kv => kv.Key).ToList())
+                    _map.Remove(k);
+            Save();
+        }
+    }
+
+    public void Clear()
+    {
+        lock (_lock)
+        {
+            _map.Clear();
+            try { if (File.Exists(_path)) File.Delete(_path); } catch { }
+        }
+    }
+
+    private void Save()
+    {
+        try
+        {
+            var dir = Path.GetDirectoryName(_path);
+            if (!string.IsNullOrEmpty(dir)) Directory.CreateDirectory(dir);
+            var tmp = _path + ".tmp";
+            File.WriteAllText(tmp, JsonSerializer.Serialize(_map));
+            File.Move(tmp, _path, overwrite: true);
+        }
+        catch
+        {
+            // 저장 실패는 메모리 상태는 유지(조용한 내구성 저하)
+        }
+    }
+
+    private static string? NormalizeHost(string? url)
+    {
+        if (string.IsNullOrWhiteSpace(url)) return null;
+        if (!Uri.TryCreate(url, UriKind.Absolute, out var uri) || string.IsNullOrEmpty(uri.Host)) return null;
+        var host = uri.Host;
+        return host.StartsWith("www.", StringComparison.OrdinalIgnoreCase) ? host[4..] : host;
+    }
+}

VideoDownloader.Browser/Tabs/TabItem.cs

@@ -0,0 +1,66 @@
+using System.ComponentModel;
+using System.Runtime.CompilerServices;
+using Microsoft.Web.WebView2.Wpf;
+
+namespace VideoDownloader.Browser.Tabs;
+
+/// <summary>탭 하나의 상태. View(WebView2 컨트롤)는 앱 레이어에서 주입한다(단위 테스트에선 null).</summary>
+public sealed class TabItem : INotifyPropertyChanged
+{
+    public Guid Id { get; } = Guid.NewGuid();
+
+    /// <summary>탭에 연결된 WebView2 컨트롤. 닫힌 탭 재오픈 시 재생성될 수 있음.</summary>
+    public WebView2? View { get; set; }
+
+    /// <summary>CoreWebView2 (초기화 전 null)</summary>
+    public Microsoft.Web.WebView2.Core.CoreWebView2? Core => View?.CoreWebView2;
+    private string _title = "새 탭";
+    public string Title { get => _title; set => Set(ref _title, value); }
+
+    private string _url = "";
+    public string Url { get => _url; set => Set(ref _url, value); }
+
+    private bool _isPinned;
+    public bool IsPinned { get => _isPinned; set => Set(ref _isPinned, value); }
+
+    private bool _isActive;
+    public bool IsActive { get => _isActive; set => Set(ref _isActive, value); }
+
+    private bool _isAudioPlaying;
+    public bool IsAudioPlaying { get => _isAudioPlaying; set => Set(ref _isAudioPlaying, value); }
+
+    private bool _isMuted;
+    public bool IsMuted { get => _isMuted; set => Set(ref _isMuted, value); }
+
+    private bool _isSuspended;
+    public bool IsSuspended { get => _isSuspended; set => Set(ref _isSuspended, value); }
+
+    private bool _isLoading;
+    public bool IsLoading { get => _isLoading; set => Set(ref _isLoading, value); }
+
+    /// <summary>마지막 활성 시각(탭 절전 판정용)</summary>
+    public DateTime LastActivated { get; set; } = DateTime.UtcNow;
+
+    /// <summary>닫힌 시점의 인덱스(닫힌 탭 복원용). 열려 있는 동안은 무의미.</summary>
+    internal int ClosedIndex { get; set; } = -1;
+
+    // ---- 탭별 일시 상태(호스트 앱이 사용) ----
+    /// <summary>SourceChanged → 타이틀 확정 사이의 히스토리 기록 대기 URL.</summary>
+    public string? PendingHistoryUrl { get; set; }
+    /// <summary>소셜 카드 제목 갱신 대기 URL.</summary>
+    public string? PendingSocialUrl { get; set; }
+    /// <summary>탭별 페이지 내 검색 세션 (CoreWebView2 바인딩).</summary>
+    public FindSession? FindSession { get; set; }
+
+    public event PropertyChangedEventHandler? PropertyChanged;
+
+    private void Set<T>(ref T field, T value, [CallerMemberName] string? name = null)
+    {
+        if (EqualityComparer<T>.Default.Equals(field, value)) return;
+        field = value;
+        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(name));
+    }
+}
+
+/// <summary>세션 스냅샷(T1-10): 탭 URL 순서 + 활성 인덱스 + 핀 여부.</summary>
+public sealed record SessionSnapshot(List<string> Urls, int ActiveIndex, List<bool> Pinned);

VideoDownloader.Browser/Tabs/TabManager.cs

@@ -0,0 +1,164 @@
+using System.Collections.ObjectModel;
+
+namespace VideoDownloader.Browser.Tabs;
+
+/// <summary>
+/// 탭 관리 순수 로직(Phase A). WebView2 생성은 주입된 팩토리/어태처가 담당해
+/// 단위 테스트에서 UI 없이 검증 가능. 닫힌 탭 스택(25) · 핀 좌측 정렬 · 세션 캡처/복원 포함.
+/// </summary>
+public sealed class TabManager
+{
+    private const int MaxClosed = 25;
+
+    private readonly Func<TabItem> _createTab;
+    private readonly Action<TabItem>? _attachView;
+    private readonly List<(TabItem Tab, int Index)> _closed = new();
+
+    public ObservableCollection<TabItem> Tabs { get; } = new();
+    public TabItem? ActiveTab { get; private set; }
+
+    public event Action<TabItem>? ActiveChanged;
+    public event Action<TabItem>? TabAdded;
+    public event Action<TabItem>? TabRemoved;
+
+    /// <summary>닫힌 탭(LIFO — 최신 우선). Ctrl+Shift+T 복원 대상.</summary>
+    public IReadOnlyList<TabItem> ClosedStack => _closed.Select(e => e.Tab).ToList();
+
+    public TabManager(Func<TabItem> createTab, Action<TabItem>? attachView = null)
+    {
+        _createTab = createTab;
+        _attachView = attachView;
+    }
+
+    public TabItem NewTab(string? url = null, bool activate = true)
+    {
+        var tab = _createTab();
+        if (!string.IsNullOrEmpty(url)) tab.Url = url;
+        _attachView?.Invoke(tab);
+        Tabs.Add(tab); // 신규 탭은 핀 여부와 무관하게 끝에(핀 상태로 만들면 SetPinned 이동)
+        TabAdded?.Invoke(tab);
+        if (activate) Activate(tab);
+        else tab.IsActive = false;
+        return tab;
+    }
+
+    public void Activate(TabItem tab)
+    {
+        if (!Tabs.Contains(tab)) return;
+        foreach (var t in Tabs) t.IsActive = ReferenceEquals(t, tab);
+        ActiveTab = tab;
+        tab.LastActivated = DateTime.UtcNow;
+        ActiveChanged?.Invoke(tab);
+    }
+
+    /// <summary>탭 닫기. 활성 탭이면 오른쪽 이웃(없으면 왼쪽) 활성화. 마지막 탭이면 새 빈 탭으로 대체.</summary>
+    public bool CloseTab(TabItem tab)
+    {
+        var index = Tabs.IndexOf(tab);
+        if (index < 0) return false;
+
+        _closed.Insert(0, (tab, index));
+        while (_closed.Count > MaxClosed) _closed.RemoveAt(_closed.Count - 1);
+        tab.ClosedIndex = index;
+
+        var wasActive = ReferenceEquals(ActiveTab, tab);
+        Tabs.RemoveAt(index);
+        TabRemoved?.Invoke(tab);
+
+        if (Tabs.Count == 0)
+        {
+            NewTab(); // 창 유지 — 마지막 탭은 새 빈 탭으로 대체
+        }
+        else if (wasActive)
+        {
+            var next = Tabs[Math.Min(index, Tabs.Count - 1)]; // 오른쪽 우선, 끝이면 왼쪽
+            Activate(next);
+        }
+        return true;
+    }
+
+    /// <summary>Ctrl+Shift+T: 닫힌 탭을 닫힌 위치에 복원.</summary>
+    public TabItem? ReopenClosedTab()
+    {
+        if (_closed.Count == 0) return null;
+        var (tab, index) = _closed[0];
+        _closed.RemoveAt(0);
+
+        if (tab.View == null) _attachView?.Invoke(tab); // 뷰가 정리된 경우 재생성
+        Tabs.Insert(Math.Min(index, Tabs.Count), tab);
+        TabAdded?.Invoke(tab);
+        Activate(tab);
+        return tab;
+    }
+
+    public void ActivateNext()
+    {
+        if (ActiveTab == null || Tabs.Count < 2) return;
+        var i = Tabs.IndexOf(ActiveTab);
+        Activate(Tabs[(i + 1) % Tabs.Count]);
+    }
+
+    public void ActivatePrevious()
+    {
+        if (ActiveTab == null || Tabs.Count < 2) return;
+        var i = Tabs.IndexOf(ActiveTab);
+        Activate(Tabs[(i - 1 + Tabs.Count) % Tabs.Count]);
+    }
+
+    public void ActivateAt(int index)
+    {
+        if (index >= 0 && index < Tabs.Count) Activate(Tabs[index]);
+    }
+
+    public void ActivateLast() => ActivateAt(Tabs.Count - 1);
+
+    public void Move(TabItem tab, int newIndex)
+    {
+        var old = Tabs.IndexOf(tab);
+        if (old < 0) return;
+        newIndex = Math.Clamp(newIndex, 0, Tabs.Count - 1);
+        if (newIndex == old) return;
+        Tabs.Move(old, newIndex);
+    }
+
+    /// <summary>핀 설정. 핀 탭은 좌측 끝에 정렬(Chrome 동작).</summary>
+    public void SetPinned(TabItem tab, bool pinned)
+    {
+        if (!Tabs.Contains(tab)) return;
+        tab.IsPinned = pinned;
+        if (pinned)
+        {
+            var target = Tabs.Count(t => t.IsPinned) - 1; // 자신 포함 핀 탭 수 - 1
+            Move(tab, Math.Max(0, target));
+        }
+        else
+        {
+            var target = Tabs.Count(t => t.IsPinned); // 핀 탭 블록 바로 뒤
+            Move(tab, target);
+        }
+    }
+
+    public SessionSnapshot CaptureSession()
+    {
+        var active = ActiveTab == null ? 0 : Math.Max(0, Tabs.IndexOf(ActiveTab));
+        return new SessionSnapshot(
+            Tabs.Select(t => t.Url).ToList(),
+            active,
+            Tabs.Select(t => t.IsPinned).ToList());
+    }
+
+    public void RestoreSession(SessionSnapshot snap)
+    {
+        foreach (var t in Tabs.ToList())
+        {
+            Tabs.Remove(t);
+            TabRemoved?.Invoke(t);
+        }
+        for (var i = 0; i < snap.Urls.Count; i++)
+        {
+            var tab = NewTab(snap.Urls[i], activate: false);
+            if (i < snap.Pinned.Count && snap.Pinned[i]) tab.IsPinned = true; // 순서 유지(핀 우선 저장됨)
+        }
+        ActivateAt(Math.Clamp(snap.ActiveIndex, 0, Math.Max(0, Tabs.Count - 1)));
+    }
+}

VideoDownloader.Browser/Tabs/TabSessionStore.cs

@@ -0,0 +1,38 @@
+using System.IO;
+using System.Text.Json;
+
+namespace VideoDownloader.Browser.Tabs;
+
+/// <summary>세션 JSON 저장소(T1-10). 종료 시 탭 URL 저장, 시작 시 복원.</summary>
+public static class TabSessionStore
+{
+    public static void Save(string path, SessionSnapshot snap)
+    {
+        try
+        {
+            var dir = Path.GetDirectoryName(path);
+            if (!string.IsNullOrEmpty(dir)) Directory.CreateDirectory(dir);
+            var tmp = path + ".tmp";
+            File.WriteAllText(tmp, JsonSerializer.Serialize(snap));
+            File.Move(tmp, path, overwrite: true);
+        }
+        catch { }
+    }
+
+    public static SessionSnapshot? Load(string path)
+    {
+        try
+        {
+            if (!File.Exists(path)) return null;
+            var snap = JsonSerializer.Deserialize<SessionSnapshot>(File.ReadAllText(path));
+            if (snap == null || snap.Urls == null || snap.Urls.Count == 0) return null;
+            var pinned = snap.Pinned ?? new List<bool>();
+            while (pinned.Count < snap.Urls.Count) pinned.Add(false);
+            return snap with { Pinned = pinned };
+        }
+        catch
+        {
+            return null;
+        }
+    }
+}

VideoDownloader.Browser/VideoDownloader.Browser.csproj

@@ -0,0 +1,21 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFramework>net8.0-windows</TargetFramework>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <UseWPF>true</UseWPF>
+    <EnableWindowsTargeting>true</EnableWindowsTargeting>
+    <RootNamespace>VideoDownloader.Browser</RootNamespace>
+  </PropertyGroup>
+  <!-- net8.0-windows WPF 빌드 시 SDK implicit usings 보강 -->
+  <ItemGroup>
+    <Using Include="System.IO" />
+    <Using Include="System.Net.Http" />
+  </ItemGroup>
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Web.WebView2" Version="1.0.4078.44" />
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\VideoDownloader.Core\VideoDownloader.Core.csproj" />
+  </ItemGroup>
+</Project>