import type { Signature } from "@prisma/client";
import { z } from "zod";
import { SIGNATURE_OUTCOMES, SIGNATURE_REASON_REQUIRED, type SignatureBlock } from "@/lib/reports/content";
import { can, assertCan, ServiceError, type ServiceCtx } from "@/server/services/context";
// TODO(merge L2): import from "@/server/services/work-orders/transition"
import { transitionWorkOrder } from "@/server/services/work-orders/transition";
import { auditReport, contentOf, requireVisibleReport } from "./common";

const optText = (max: number) =>
  z
    .string()
    .trim()
    .max(max)
    .nullish()
    .transform((v) => (v ? v : null));

export const captureSignatureSchema = z.object({
  reportId: z.string().min(1).max(64),
  outcome: z.enum(SIGNATURE_OUTCOMES),
  signerName: optText(200),
  signerRole: optText(200),
  imageDocumentId: optText(64),
  reason: optText(2000),
  confirmationText: z.string().trim().min(1).max(2000),
  clientId: z.string().min(1).max(64).optional(),
});
export type CaptureSignatureInput = z.input<typeof captureSignatureSchema>;

/** Outcomes that count as "signature documented" for the order flow (→ in_review). */
export const SIGNATURE_DOCUMENTED = ["signed", "not_required", "customer_absent", "refused"] as const;

/**
 * Digitale Kundenunterschrift bzw. begründete Ausnahme (Spec §18).
 * - signed: signer name + PNG image document required
 * - customer_absent / refused / later: reason required
 * - not_required: only if the work order does not require a signature or caller has report:approve
 * A signed signature is never overwritten; other outcomes may be replaced (e.g. "later" → "signed").
 */
export async function captureSignature(ctx: ServiceCtx, raw: CaptureSignatureInput): Promise<Signature> {
  assertCan(ctx, "report:write");
  const input = captureSignatureSchema.parse(raw);
  if (input.clientId) {
    const dup = await ctx.db.signature.findFirst({ where: { clientId: input.clientId } });
    if (dup) return dup;
  }
  const report = await requireVisibleReport(ctx, input.reportId);
  if (report.status === "approved" || report.status === "superseded") throw new ServiceError("conflict", `report is ${report.status}`);
  const wo = await ctx.db.workOrder.findFirstOrThrow({ where: { id: report.workOrderId }, select: { id: true, status: true, signatureRequired: true } });

  if (input.outcome === "signed") {
    if (!input.signerName) throw new ServiceError("invalid", "signer name required", { field: "signerName" });
    if (!input.imageDocumentId) throw new ServiceError("invalid", "signature image required", { field: "image" });
    const doc = await ctx.db.document.findFirst({
      where: { id: input.imageDocumentId, category: "signature", mimeType: "image/png", workOrderId: wo.id, deletedAt: null },
      select: { id: true },
    });
    if (!doc) throw new ServiceError("invalid", "signature image not found", { field: "image" });
  } else if (input.imageDocumentId) {
    throw new ServiceError("invalid", "image only allowed for signed outcome", { field: "image" });
  }
  if (SIGNATURE_REASON_REQUIRED.includes(input.outcome) && !input.reason) {
    throw new ServiceError("invalid", "reason required", { field: "reason" });
  }
  if (input.outcome === "not_required" && wo.signatureRequired && !can(ctx, "report:approve")) {
    throw new ServiceError("forbidden", "signature is required for this work order");
  }

  const existing = await ctx.db.signature.findFirst({ where: { reportId: report.id } });
  if (existing?.outcome === "signed") throw new ServiceError("conflict", "signature already captured");

  const data = {
    outcome: input.outcome,
    signerName: input.signerName,
    signerRole: input.signerRole,
    imageDocumentId: input.outcome === "signed" ? input.imageDocumentId : null,
    confirmationText: input.confirmationText,
    reason: input.reason,
    signedAt: new Date(),
    capturedById: ctx.userId,
  };
  const signature = existing
    ? await ctx.db.signature.update({ where: { id: existing.id }, data })
    : await ctx.db.signature.create({ data: { ...data, tenantId: ctx.tenantId, reportId: report.id, clientId: input.clientId ?? null } });

  const me = await ctx.db.user.findFirst({ where: { id: ctx.userId }, select: { name: true } });
  const block: SignatureBlock = {
    outcome: signature.outcome,
    signerName: signature.signerName,
    signerRole: signature.signerRole,
    signedAt: signature.signedAt.toISOString(),
    reason: signature.reason,
    confirmationText: signature.confirmationText,
    imageDocumentId: signature.imageDocumentId,
    capturedByName: me?.name ?? null,
  };
  const content = contentOf(report);
  await ctx.db.report.update({ where: { id: report.id }, data: { content: { ...content, signature: block } } });

  const view = (s: Pick<Signature, "outcome" | "signerName" | "signerRole" | "reason" | "imageDocumentId"> | null) =>
    s && { reportId: report.id, outcome: s.outcome, signerName: s.signerName, signerRole: s.signerRole, reason: s.reason, imageDocumentId: s.imageDocumentId };
  await auditReport(ctx, existing ? "update" : "create", signature.id, view(existing), view(signature), "signature");

  // Signature captured after submit: order waiting for it can move on to review.
  if (
    report.type === "completion" &&
    wo.status === "signature_pending" &&
    (SIGNATURE_DOCUMENTED as readonly string[]).includes(signature.outcome) &&
    can(ctx, "field:execute")
  ) {
    await transitionWorkOrder(ctx, { workOrderId: wo.id, to: "in_review", eventData: { occurrenceId: `${report.id}:signature:${signature.id}` } });
  }
  return signature;
}