namespace AxCopilot.Services;

/// <summary>
/// 실행 중/최근 task 상태를 관리하는 전용 저장소.
/// AppStateService와 UI가 같은 로직을 공유할 수 있게 분리합니다.
/// </summary>
public sealed class TaskRunStore
{
    public sealed class TaskRun
    {
        public string Id { get; init; } = "";
        public string Kind { get; set; } = "";
        public string Title { get; set; } = "";
        public string Status { get; set; } = "running";
        public string Summary { get; set; } = "";
        public DateTime StartedAt { get; set; } = DateTime.Now;
        public DateTime UpdatedAt { get; set; } = DateTime.Now;
        public string? FilePath { get; set; }
    }

    private readonly List<TaskRun> _active = new();
    private readonly List<TaskRun> _recent = new();

    public IReadOnlyList<TaskRun> ActiveTasks => _active;
    public IReadOnlyList<TaskRun> RecentTasks => _recent;

    public event Action? Changed;

    public void Upsert(string id, string kind, string title, string summary, string status = "running", string? filePath = null)
    {
        var existing = _active.FirstOrDefault(t => string.Equals(t.Id, id, StringComparison.OrdinalIgnoreCase));
        if (existing == null)
        {
            _active.Add(new TaskRun
            {
                Id = id,
                Kind = kind,
                Title = title,
                Summary = summary,
                Status = status,
                FilePath = filePath,
                StartedAt = DateTime.Now,
                UpdatedAt = DateTime.Now,
            });
            Changed?.Invoke();
            return;
        }

        existing.Kind = kind;
        existing.Title = title;
        existing.Summary = summary;
        existing.Status = status;
        existing.FilePath = filePath;
        existing.UpdatedAt = DateTime.Now;
        Changed?.Invoke();
    }

    public void Complete(string id, string? summary = null, string status = "completed")
    {
        var existing = _active.FirstOrDefault(t => string.Equals(t.Id, id, StringComparison.OrdinalIgnoreCase));
        if (existing == null)
            return;

        _active.Remove(existing);
        existing.Status = status;
        if (!string.IsNullOrWhiteSpace(summary))
            existing.Summary = summary;
        existing.UpdatedAt = DateTime.Now;
        _recent.Insert(0, existing);
        TrimRecent();
        Changed?.Invoke();
    }

    public void CompleteByPrefix(string prefix, string? summary = null, string status = "completed")
    {
        var matches = _active
            .Where(t => t.Id.StartsWith(prefix, StringComparison.OrdinalIgnoreCase))
            .ToList();

        foreach (var match in matches)
        {
            _active.Remove(match);
            match.Status = status;
            if (!string.IsNullOrWhiteSpace(summary))
                match.Summary = summary;
            match.UpdatedAt = DateTime.Now;
            _recent.Insert(0, match);
        }

        if (matches.Count == 0)
            return;

        TrimRecent();
        Changed?.Invoke();
    }

    public void RestoreRecent(IEnumerable<TaskRun>? recent)
    {
        RestoreState(null, recent);
    }

    public void RestoreState(IEnumerable<TaskRun>? active, IEnumerable<TaskRun>? recent)
    {
        _active.Clear();
        _recent.Clear();

        if (active != null)
        {
            _active.AddRange(active
                .OrderByDescending(t => t.UpdatedAt)
                .Take(25));
        }

        if (recent != null)
        {
            _recent.AddRange(recent
                .OrderByDescending(t => t.UpdatedAt)
                .Take(25));
        }

        Changed?.Invoke();
    }

    private void TrimRecent()
    {
        if (_recent.Count > 25)
            _recent.RemoveRange(25, _recent.Count - 25);
    }
}