import type { PrismaClient } from '@generated/prisma/client';
import type {
  AttendeePaymentStatus,
  ClassToday,
  ProblemDetails,
  Result,
} from '@gruperly/shared';
import { err } from '@gruperly/shared';
import { noGroupAccessProblem, notFoundResourceProblem } from '@/http/problem-builders';

export type ClassesDb = Pick<
  PrismaClient,
  'group' | 'classSession' | 'attendee' | 'payment' | 'attendance' | 'slotRelease'
>;

type PaymentLike = {
  status: 'PENDING' | 'PAID' | 'OVERDUE' | 'CANCELLED';
  dueDate: Date;
};

// Estado de cobro calculado en tiempo real (sin columna denormalizada):
// PENDIENTE si hay un pago vencido (OVERDUE) o un PENDING cuyo vencimiento ya pasó.
export function resolvePaymentStatus(
  payments: PaymentLike[],
  startOfToday: Date,
): AttendeePaymentStatus {
  const hasUnpaid = payments.some(
    (payment) =>
      payment.status === 'OVERDUE'
      || (payment.status === 'PENDING' && payment.dueDate.getTime() < startOfToday.getTime()),
  );
  return hasUnpaid ? 'PENDING' : 'UP_TO_DATE';
}

export function absenceReleaseHours(): number {
  const raw = process.env.ABSENCE_RELEASE_HOURS;
  if (raw == null || raw.trim() === '') {
    return 12;
  }
  const parsed = Number(raw);
  return Number.isFinite(parsed) && parsed >= 0 ? parsed : 12;
}

export type ClassSessionRecord = {
  id: string;
  groupId: string;
  startsAt: Date;
};

type GroupWithAccess = {
  createdById: string;
  members: { userId: string }[];
};

// Verifica que el usuario sea owner o miembro del grupo dueño de la sesión.
export function ensureSessionAccess(
  session: ClassSessionRecord & { group: GroupWithAccess },
  userId: string,
): Result<ClassSessionRecord, ProblemDetails> {
  const isOwner = session.group.createdById === userId;
  const isMember = session.group.members.length > 0;
  if (!isOwner && !isMember) {
    return err(noGroupAccessProblem());
  }
  return {
    ok: true,
    value: { id: session.id, groupId: session.groupId, startsAt: session.startsAt },
  };
}

export function sessionNotFound(sessionId: string): ProblemDetails {
  return notFoundResourceProblem('Class session', sessionId);
}

export function toClassToday(
  session: { id: string; startsAt: Date },
  group: { id: string; name: string; capacity: number | null },
  enrolledCount: number,
  hasAttendance: boolean,
): ClassToday {
  return {
    sessionId: session.id,
    groupId: group.id,
    groupName: group.name,
    startsAt: session.startsAt.toISOString(),
    enrolledCount,
    capacity: group.capacity,
    availableSlots:
      group.capacity == null ? null : Math.max(0, group.capacity - enrolledCount),
    hasAttendance,
  };
}