export type LimitWarningTone = 'warning' | 'danger';

export type LimitWarning = {
  id: string;
  scope: 'photos' | 'guests' | 'gallery';
  tone: LimitWarningTone;
  message: string;
};

export type LimitUsageSummary = {
  limit: number | null;
  used: number;
  remaining: number | null;
  percentage: number | null;
  state: 'ok' | 'warning' | 'limit_reached' | 'unlimited';
  threshold_reached: number | null;
  next_threshold: number | null;
  thresholds: number[];
} | null;

export type GallerySummary = {
  state: 'ok' | 'warning' | 'expired' | 'unlimited';
  expires_at: string | null;
  days_remaining: number | null;
  warning_thresholds: number[];
  warning_triggered: number | null;
  warning_sent_at: string | null;
  expired_notified_at: string | null;
} | null;

export type EventLimitSummary = {
  photos: LimitUsageSummary;
  guests: LimitUsageSummary;
  gallery: GallerySummary;
  can_upload_photos: boolean;
  can_add_guests: boolean;
} | null | undefined;

type TranslateFn = (key: string, options?: Record<string, unknown>) => string;

function hasRemaining(summary: LimitUsageSummary): summary is LimitUsageSummary & { remaining: number; limit: number } {
  return Boolean(summary)
    && typeof summary?.remaining === 'number'
    && typeof summary?.limit === 'number';
}

export function buildLimitWarnings(limits: EventLimitSummary, t: TranslateFn): LimitWarning[] {
  if (!limits) {
    return [];
  }

  const warnings: LimitWarning[] = [];

  if (limits.photos) {
    if (limits.photos.state === 'limit_reached') {
      warnings.push({
        id: 'photos-limit',
        scope: 'photos',
        tone: 'danger',
        message: t('photosBlocked'),
      });
    } else if (limits.photos.state === 'warning' && hasRemaining(limits.photos)) {
      warnings.push({
        id: 'photos-warning',
        scope: 'photos',
        tone: 'warning',
        message: t('photosWarning', {
          remaining: limits.photos.remaining,
          limit: limits.photos.limit,
        }),
      });
    }
  }

  if (limits.guests) {
    if (limits.guests.state === 'limit_reached') {
      warnings.push({
        id: 'guests-limit',
        scope: 'guests',
        tone: 'danger',
        message: t('guestsBlocked'),
      });
    } else if (limits.guests.state === 'warning' && hasRemaining(limits.guests)) {
      warnings.push({
        id: 'guests-warning',
        scope: 'guests',
        tone: 'warning',
        message: t('guestsWarning', {
          remaining: limits.guests.remaining,
          limit: limits.guests.limit,
        }),
      });
    }
  }

  if (limits.gallery) {
    if (limits.gallery.state === 'expired') {
      warnings.push({
        id: 'gallery-expired',
        scope: 'gallery',
        tone: 'danger',
        message: t('galleryExpired'),
      });
    } else if (limits.gallery.state === 'warning') {
      const days = limits.gallery.days_remaining ?? 0;
      const safeDays = Math.max(0, days);
      const key = safeDays === 1 ? 'galleryWarningDay' : 'galleryWarningDays';
      warnings.push({
        id: 'gallery-warning',
        scope: 'gallery',
        tone: 'warning',
        message: t(key, { days: safeDays }),
      });
    }
  }

  return warnings;
}