'use server';

import { revalidatePath } from 'next/cache';

import { diffOf, recordAudit } from '@/lib/audit';
import { requireAdmin } from '@/lib/auth/actions';
import { prisma } from '@/lib/db';
import type { CivilDate } from '@/lib/schedule/civil';
import { checkRange, expandRange, MAX_RANGE_DAYS } from '@/lib/schedule/exceptions';
import type { Slot } from '@/lib/schedule/types';
import { validateSlots } from '@/lib/schedule/validate';

export type ExceptionReason = 'TEMPORARY' | 'SPECIAL_EVENT';

export type ActionResult = { ok: true } | { ok: false; error: string };

export type ExceptionInput = {
  date: CivilDate;
  isClosed: boolean;
  slots: Slot[];
  reason: ExceptionReason;
  noteFr: string | null;
};

export async function saveException(input: ExceptionInput): Promise<ActionResult> {
  const gate = await requireAdmin();
  if (!gate.ok) {
    return { ok: false, error: gate.error };
  }

  const slots = input.isClosed ? [] : input.slots;
  if (!input.isClosed) {
    const problems = validateSlots(slots);
    if (slots.length === 0) {
      problems.push('Une ouverture exceptionnelle doit avoir au moins une plage horaire.');
    }
    if (problems.length > 0) {
      return { ok: false, error: problems.join(' ') };
    }
  }

  const date = asDate(input.date);
  const existing = await prisma.scheduleException.findUnique({ where: { date } });

  await prisma.scheduleException.upsert({
    where: { date },
    update: {
      isClosed: input.isClosed,
      slots: input.isClosed ? undefined : slots,
      reason: input.reason,
      noteFr: input.noteFr,
      // The French text changed, so any English translation is stale.
      noteEn: existing?.noteFr === input.noteFr ? undefined : null,
      source: 'MANUAL',
    },
    create: {
      date,
      isClosed: input.isClosed,
      slots: input.isClosed ? undefined : slots,
      reason: input.reason,
      noteFr: input.noteFr,
      source: 'MANUAL',
      createdBy: gate.value.email,
    },
  });

  await recordAudit({
    userEmail: gate.value.email,
    action: existing ? 'exception.update' : 'exception.create',
    entity: 'ScheduleException',
    entityId: input.date,
    diff: diffOf(
      existing ? { fermé: existing.isClosed, horaires: summarise(existing.slots as Slot[] | null), note: existing.noteFr } : null,
      { fermé: input.isClosed, horaires: summarise(slots), note: input.noteFr },
    ),
  });

  revalidateAll();
  return { ok: true };
}

export async function saveExceptionRange(input: {
  start: CivilDate;
  end: CivilDate;
  noteFr: string | null;
}): Promise<ActionResult> {
  const gate = await requireAdmin();
  if (!gate.ok) {
    return { ok: false, error: gate.error };
  }

  const problem = checkRange(input.start, input.end);
  if (problem === 'EMPTY') {
    return { ok: false, error: 'Indiquez une date de début et une date de fin.' };
  }
  if (problem === 'REVERSED') {
    return { ok: false, error: 'La date de fin précède la date de début.' };
  }
  if (problem === 'TOO_LONG') {
    return {
      ok: false,
      error: `Période trop longue (${MAX_RANGE_DAYS} jours au maximum). Utilisez les vacances pour une fermeture plus longue.`,
    };
  }

  const dates = expandRange(input.start, input.end);

  await prisma.$transaction(
    dates.map((date) =>
      prisma.scheduleException.upsert({
        where: { date: asDate(date) },
        update: { isClosed: true, slots: undefined, reason: 'TEMPORARY', noteFr: input.noteFr, noteEn: null, source: 'MANUAL' },
        create: {
          date: asDate(date),
          isClosed: true,
          reason: 'TEMPORARY',
          noteFr: input.noteFr,
          source: 'MANUAL',
          createdBy: gate.value.email,
        },
      }),
    ),
  );

  await recordAudit({
    userEmail: gate.value.email,
    action: 'exception.create_range',
    entity: 'ScheduleException',
    entityId: `${input.start}…${input.end}`,
    diff: { période: { before: null, after: `${dates.length} jours fermés` } },
  });

  revalidateAll();
  return { ok: true };
}

export async function deleteException(date: CivilDate): Promise<ActionResult> {
  const gate = await requireAdmin();
  if (!gate.ok) {
    return { ok: false, error: gate.error };
  }

  const existing = await prisma.scheduleException.findUnique({ where: { date: asDate(date) } });
  if (!existing) {
    return { ok: false, error: 'Cette exception a déjà été supprimée.' };
  }

  await prisma.scheduleException.delete({ where: { date: asDate(date) } });

  await recordAudit({
    userEmail: gate.value.email,
    action: 'exception.delete',
    entity: 'ScheduleException',
    entityId: date,
    diff: diffOf(
      { fermé: existing.isClosed, horaires: summarise(existing.slots as Slot[] | null), note: existing.noteFr },
      null,
    ),
  });

  revalidateAll();
  return { ok: true };
}

function summarise(slots: Slot[] | null): string {
  if (!slots || slots.length === 0) {
    return 'Fermé';
  }
  return slots.map((slot) => `${slot.open}–${slot.close}`).join(' · ');
}

function asDate(value: CivilDate): Date {
  return new Date(`${value}T00:00:00.000Z`);
}

function revalidateAll(): void {
  revalidatePath('/admin');
  revalidatePath('/admin/exceptions');
}