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();
}