import { z } from "zod";
import { prisma } from "@/server/db";
import { writeAuditLog } from "@/server/audit";
import { issueToken } from "@/server/auth-token";
import { sendUserInvitationMail } from "@/server/auth-selfservice";
import { ServiceError } from "@/server/services/context";
import { addDaysToKey, isDateKey, todayKey, trialEndInstant } from "@/lib/trial/dates";
import { daysMs, PLATFORM_TRIAL_MAX_DAYS, TRIAL_DELETION_GRACE_DAYS, TRIAL_DELETION_NOTICE_DAYS } from "./config";
import { provisionTrialTenant, type ProvisionTrialResult } from "./provision";

/**
 * L15 Testphase: platform-admin operations on trial tenants. ONLY for active platform full admins —
 * every function re-checks the actor against the PlatformAdmin store (tenant administrators have no
 * PlatformAdmin row and are rejected with `forbidden`). The adapter additionally requires the
 * platform session (src/server/actions/trial-platform.ts). Every change → audit (scope platform,
 * attached to the tenant so it shows in the tenant's audit trail) with before/after.
 */

export type PlatformActor = { platformAdminId: string };

async function assertPlatformFullAdmin(actor: PlatformActor): Promise<void> {
  const admin = actor.platformAdminId
    ? await prisma.platformAdmin.findUnique({ where: { id: actor.platformAdminId }, select: { status: true, role: true } })
    : null;
  if (!admin || admin.status !== "ACTIVE" || admin.role !== "full") throw new ServiceError("forbidden", "platform_admin_required");
}

const LIFECYCLE_SELECT = {
  id: true,
  name: true,
  status: true,
  plan: true,
  trialEndsAt: true,
  convertedAt: true,
  readOnlySince: true,
  deletionDueAt: true,
  trialDeletedAt: true,
} as const;

async function loadTrialTenant(tenantId: string) {
  const tenant = await prisma.tenant.findUnique({ where: { id: tenantId }, select: LIFECYCLE_SELECT });
  if (!tenant) throw new ServiceError("not_found", "tenant not found");
  if (tenant.trialDeletedAt || tenant.status === "ARCHIVED") throw new ServiceError("invalid", "tenant_deleted");
  if (tenant.plan !== "TRIAL" || !tenant.trialEndsAt) throw new ServiceError("invalid", "not_a_trial");
  return tenant;
}

type Snapshot = { plan: string; trialEndsAt: Date | null; readOnlySince: Date | null; deletionDueAt: Date | null; convertedAt: Date | null };
const snap = (t: Snapshot) => ({ plan: t.plan, trialEndsAt: t.trialEndsAt, readOnlySince: t.readOnlySince, deletionDueAt: t.deletionDueAt, convertedAt: t.convertedAt });

async function audit(actor: PlatformActor, tenantId: string, entity: string, before: Snapshot, after: Snapshot) {
  await writeAuditLog({ tenantId, scope: "platform", actorId: actor.platformAdminId, action: "update", entity, entityId: tenantId, before: snap(before), after: snap(after) });
}

const RESET_NOTICES = { trialReminder7At: null, trialReminder3At: null, trialReminder1At: null, trialExpiredNoticeAt: null, trialDeletionNoticeAt: null } as const;

export const platformTrialSchema = z.object({
  companyName: z.string().trim().min(2).max(120),
  sector: z.string().trim().max(80).default(""),
  adminName: z.string().trim().min(2).max(120),
  adminEmail: z.string().trim().toLowerCase().max(200).regex(/^[^\s@]+@[^\s@]+\.[^\s@]{2,}$/),
  endDate: z.string().refine(isDateKey, "date_invalid"),
  sampleData: z.boolean().default(true),
});

function assertEndDateRange(endDateKey: string, now: Date) {
  if (!isDateKey(endDateKey)) throw new ServiceError("invalid", "date_invalid", { field: "endDate" });
  const today = todayKey(now);
  if (endDateKey < today) throw new ServiceError("invalid", "date_in_past", { field: "endDate" });
  if (endDateKey > addDaysToKey(today, PLATFORM_TRIAL_MAX_DAYS)) throw new ServiceError("invalid", "date_too_late", { field: "endDate" });
}

/** Wizard "Testmandant anlegen": provisioning + invitation of a NEW admin identity (existing people keep their access). */
export async function createPlatformTrialTenant(
  actor: PlatformActor,
  raw: z.input<typeof platformTrialSchema>,
  opts: { now?: Date; invite?: (input: Parameters<typeof sendUserInvitationMail>[0]) => Promise<unknown> } = {},
): Promise<ProvisionTrialResult & { invited: boolean }> {
  await assertPlatformFullAdmin(actor);
  const now = opts.now ?? new Date();
  const input = platformTrialSchema.parse(raw);
  assertEndDateRange(input.endDate, now);
  const result = await provisionTrialTenant({
    companyName: input.companyName,
    sector: input.sector,
    admin: { name: input.adminName, email: input.adminEmail },
    endDateKey: input.endDate,
    sampleData: input.sampleData,
    source: "platform",
    actorId: actor.platformAdminId,
    now,
  });
  let invited = false;
  if (result.identityCreated) {
    const { raw: token, expiresAt } = await issueToken({ principalType: "identity", principalId: result.identityId, tenantId: result.tenantId, type: "invitation" });
    await (opts.invite ?? sendUserInvitationMail)({ to: input.adminEmail, name: input.adminName, tenantId: result.tenantId, tenantName: input.companyName, rawToken: token, expiresAt });
    invited = true;
  }
  return { ...result, invited };
}

/** Change/extend the end date — also after expiry (the tenant becomes writable again). */
export async function changeTrialEndDate(actor: PlatformActor, tenantId: string, endDateKey: string, opts: { now?: Date } = {}) {
  await assertPlatformFullAdmin(actor);
  const now = opts.now ?? new Date();
  assertEndDateRange(endDateKey, now);
  const before = await loadTrialTenant(tenantId);
  const endsAt = trialEndInstant(endDateKey);
  const after = await prisma.tenant.update({
    where: { id: tenantId },
    data: {
      trialEndsAt: endsAt,
      readOnlySince: null,
      // a cancelled deletion stays cancelled; otherwise the grace period follows the new end
      deletionDueAt: before.deletionDueAt ? new Date(endsAt.getTime() + daysMs(TRIAL_DELETION_GRACE_DAYS)) : null,
      ...RESET_NOTICES,
    },
    select: LIFECYCLE_SELECT,
  });
  await audit(actor, tenantId, "trial_end_date", before, after);
  return after;
}

/** Convert to the full version: never deleted, never read-only again. */
export async function convertTenantToFull(actor: PlatformActor, tenantId: string, opts: { now?: Date } = {}) {
  await assertPlatformFullAdmin(actor);
  const before = await loadTrialTenant(tenantId);
  const after = await prisma.tenant.update({
    where: { id: tenantId },
    data: { plan: "FULL", convertedAt: opts.now ?? new Date(), readOnlySince: null, deletionDueAt: null, trialDeletionNoticeAt: null },
    select: LIFECYCLE_SELECT,
  });
  await audit(actor, tenantId, "trial_converted", before, after);
  return after;
}

/** End the trial immediately (read-only from now on). */
export async function endTrialNow(actor: PlatformActor, tenantId: string, opts: { now?: Date } = {}) {
  await assertPlatformFullAdmin(actor);
  const now = opts.now ?? new Date();
  const before = await loadTrialTenant(tenantId);
  const after = await prisma.tenant.update({
    where: { id: tenantId },
    data: {
      trialEndsAt: now,
      readOnlySince: now,
      deletionDueAt: before.deletionDueAt ? new Date(now.getTime() + daysMs(TRIAL_DELETION_GRACE_DAYS)) : null,
      trialExpiredNoticeAt: null,
      trialDeletionNoticeAt: null,
    },
    select: LIFECYCLE_SELECT,
  });
  await audit(actor, tenantId, "trial_ended", before, after);
  return after;
}

/** Schedule the automatic deletion (end + 30 days, at least TRIAL_DELETION_NOTICE_DAYS from now so the notice can go out). */
export async function scheduleTrialDeletion(actor: PlatformActor, tenantId: string, opts: { now?: Date } = {}) {
  await assertPlatformFullAdmin(actor);
  const now = opts.now ?? new Date();
  const before = await loadTrialTenant(tenantId);
  const due = Math.max(before.trialEndsAt!.getTime() + daysMs(TRIAL_DELETION_GRACE_DAYS), now.getTime() + daysMs(TRIAL_DELETION_NOTICE_DAYS));
  const after = await prisma.tenant.update({ where: { id: tenantId }, data: { deletionDueAt: new Date(due), trialDeletionNoticeAt: null }, select: LIFECYCLE_SELECT });
  await audit(actor, tenantId, "trial_deletion_scheduled", before, after);
  return after;
}

export async function cancelTrialDeletion(actor: PlatformActor, tenantId: string) {
  await assertPlatformFullAdmin(actor);
  const before = await loadTrialTenant(tenantId);
  const after = await prisma.tenant.update({ where: { id: tenantId }, data: { deletionDueAt: null, trialDeletionNoticeAt: null }, select: LIFECYCLE_SELECT });
  await audit(actor, tenantId, "trial_deletion_cancelled", before, after);
  return after;
}