namespace AxCopilot.Services;

/// <summary>
/// 장시간 실행되거나 메인 응답 흐름과 분리된 작업을 앱 전역에서 추적합니다.
/// 현재는 서브에이전트/분리 작업을 우선 배경 작업으로 취급합니다.
/// </summary>
public sealed class BackgroundJobService
{
    public sealed class BackgroundJobState
    {
        public string Id { get; set; } = "";
        public string Kind { get; set; } = "";
        public string Title { get; set; } = "";
        public string Summary { get; set; } = "";
        public string Status { get; set; } = "running";
        public DateTime StartedAt { get; set; } = DateTime.Now;
        public DateTime UpdatedAt { get; set; } = DateTime.Now;
    }

    private readonly List<BackgroundJobState> _active = [];
    private readonly List<BackgroundJobState> _recent = [];

    public IReadOnlyList<BackgroundJobState> ActiveJobs => _active;
    public IReadOnlyList<BackgroundJobState> RecentJobs => _recent;

    public event Action? Changed;

    public void Upsert(string id, string kind, string title, string summary, string status = "running")
    {
        var existing = _active.FirstOrDefault(x => string.Equals(x.Id, id, StringComparison.OrdinalIgnoreCase));
        if (existing == null)
        {
            _active.Insert(0, new BackgroundJobState
            {
                Id = id,
                Kind = kind,
                Title = title,
                Summary = summary,
                Status = status,
                StartedAt = DateTime.Now,
                UpdatedAt = DateTime.Now,
            });
        }
        else
        {
            existing.Kind = kind;
            existing.Title = title;
            existing.Summary = summary;
            existing.Status = status;
            existing.UpdatedAt = DateTime.Now;
        }

        Changed?.Invoke();
    }

    public void Complete(string id, string? summary = null, string status = "completed")
    {
        var existing = _active.FirstOrDefault(x => string.Equals(x.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);
        if (_recent.Count > 20)
            _recent.RemoveRange(20, _recent.Count - 20);
        Changed?.Invoke();
    }
}