using System.Text.RegularExpressions;

namespace DECompanion.Windows;

public sealed record StudyProgram(
    string Id,
    string Title,
    string PlanUrl,
    string? DetailsUrl,
    string? OverviewUrl,
    string? Code,
    string? FamilyTitle,
    string? DegreeTitle)
{
    public string CohortLabel
    {
        get
        {
            if (!string.IsNullOrWhiteSpace(Code))
                return Code.Trim().ToUpperInvariant();

            var match = Regex.Match(Title, @"[A-Z]{2,}\d{2}(?:-\d+)?");
            return match.Success ? match.Value.ToUpperInvariant() : Id.ToUpperInvariant();
        }
    }

    public string DisplayFamilyTitle
    {
        get
        {
            if (!string.IsNullOrWhiteSpace(FamilyTitle))
                return FamilyTitle.Trim();

            var label = CohortLabel;
            var cleaned = Title.Replace(label, "", StringComparison.OrdinalIgnoreCase).Trim();
            return string.IsNullOrWhiteSpace(cleaned) ? Title : cleaned;
        }
    }

    public string SelectionSubtitle =>
        string.Join(" · ", new[] { DegreeTitle, CohortLabel }.Where(v => !string.IsNullOrWhiteSpace(v)));
}

public sealed record TimetableEvent(
    string Id,
    string Subject,
    DateTimeOffset StartDate,
    DateTimeOffset EndDate,
    string Lecturer,
    string Room,
    string? Note,
    string? ColorHex,
    bool IsAllDay)
{
    public bool IsToday => StartDate.LocalDateTime.Date == DateTime.Today;
    public bool IsUpcoming => EndDate >= DateTimeOffset.Now;
    public bool IsLive => StartDate <= DateTimeOffset.Now && EndDate >= DateTimeOffset.Now;
    public string RoomLabel => string.IsNullOrWhiteSpace(Room) || Room.Trim() == "." ? "Raum folgt" : Room.Trim();
    public string LecturerLabel => string.IsNullOrWhiteSpace(Lecturer) ? "Dozent folgt" : Lecturer.Trim();
    public string TimeRangeText => $"{StartDate.LocalDateTime:HH:mm} - {EndDate.LocalDateTime:HH:mm}";
    public string DayText => StartDate.LocalDateTime.ToString("dddd, dd.MM.yyyy");
}

public sealed record MensaMeal(
    string Id,
    string Category,
    string Title,
    string PriceText,
    string? ImageUrl)
{
    public string PreviewTitle => Regex.Replace(Title, @"\s*\(\s*\d+(?:\s*,\s*\d+)*\s*\)", "").Trim();
}

public sealed record MensaDayMenu(
    string Id,
    string LocationTitle,
    DateTime Date,
    IReadOnlyList<MensaMeal> Meals)
{
    public string Title => Date.Date == DateTime.Today ? "Heute"
        : Date.Date == DateTime.Today.AddDays(1) ? "Morgen"
        : Date.ToString("dddd, dd.MM.");
}

public sealed record CampusLiveEntry(
    string ProgramCode,
    string Subject,
    string Room,
    string TimeRange)
{
    public string Id => ProgramCode;
}

public enum FeedStateStyle
{
    Live,
    Fallback,
    Error
}

public sealed record FeedState(string Label, string Detail, FeedStateStyle Style)
{
    public static FeedState Idle { get; } = new("Noch nicht geladen", "Warte auf die erste Synchronisation.", FeedStateStyle.Fallback);
}

public sealed record DataSnapshot(
    DateTimeOffset GeneratedAt,
    StudyProgram? SelectedProgram,
    IReadOnlyList<StudyProgram> Programs,
    IReadOnlyList<TimetableEvent> TimetableEvents,
    IReadOnlyList<MensaDayMenu> MensaMenus,
    IReadOnlyList<CampusLiveEntry> CampusEntries,
    FeedState ProgramState,
    FeedState TimetableState,
    FeedState MensaState,
    FeedState CampusState)
{
    public static DataSnapshot Empty { get; } = new(
        DateTimeOffset.Now,
        null,
        Array.Empty<StudyProgram>(),
        Array.Empty<TimetableEvent>(),
        Array.Empty<MensaDayMenu>(),
        Array.Empty<CampusLiveEntry>(),
        FeedState.Idle,
        FeedState.Idle,
        FeedState.Idle,
        FeedState.Idle);

    public TimetableEvent? NextEvent => TimetableEvents.Where(e => e.IsUpcoming).OrderBy(e => e.StartDate).FirstOrDefault();
    public IReadOnlyList<TimetableEvent> TodayEvents => TimetableEvents.Where(e => e.IsToday).OrderBy(e => e.StartDate).ToList();
    public MensaDayMenu? PrimaryMensaMenu => MensaMenus.FirstOrDefault(m => m.Date.Date >= DateTime.Today && m.Meals.Count > 0)
        ?? MensaMenus.FirstOrDefault(m => m.Meals.Count > 0);
}