documenso/apps/web/src/app/(signing)/sign/[token]/signature-field.tsx

'use client';

import { useMemo, useState, useTransition } from 'react';

import { useRouter } from 'next/navigation';

import { Loader } from 'lucide-react';

import { DO_NOT_INVALIDATE_QUERY_ON_MUTATION } from '@documenso/lib/constants/trpc';
import { AppError, AppErrorCode } from '@documenso/lib/errors/app-error';
import type { TRecipientActionAuth } from '@documenso/lib/types/document-auth';
import { type Recipient } from '@documenso/prisma/client';
import type { FieldWithSignature } from '@documenso/prisma/types/field-with-signature';
import { trpc } from '@documenso/trpc/react';
import type {
  TRemovedSignedFieldWithTokenMutationSchema,
  TSignFieldWithTokenMutationSchema,
} from '@documenso/trpc/server/field-router/schema';
import { Button } from '@documenso/ui/primitives/button';
import { Dialog, DialogContent, DialogFooter, DialogTitle } from '@documenso/ui/primitives/dialog';
import { Label } from '@documenso/ui/primitives/label';
import { SignaturePad } from '@documenso/ui/primitives/signature-pad';
import { useToast } from '@documenso/ui/primitives/use-toast';

import { SigningDisclosure } from '~/components/general/signing-disclosure';

import { useRequiredDocumentAuthContext } from './document-auth-provider';
import { useRequiredSigningContext } from './provider';
import { SigningFieldContainer } from './signing-field-container';

type SignatureFieldState = 'empty' | 'signed-image' | 'signed-text';

export type SignatureFieldProps = {
  field: FieldWithSignature;
  recipient: Recipient;
  onSignField?: (value: TSignFieldWithTokenMutationSchema) => Promise<void> | void;
  onUnsignField?: (value: TRemovedSignedFieldWithTokenMutationSchema) => Promise<void> | void;
};

export const SignatureField = ({
  field,
  recipient,
  onSignField,
  onUnsignField,
}: SignatureFieldProps) => {
  const router = useRouter();

  const { toast } = useToast();

  const { signature: providedSignature, setSignature: setProvidedSignature } =
    useRequiredSigningContext();

  const { executeActionAuthProcedure } = useRequiredDocumentAuthContext();

  const [isPending, startTransition] = useTransition();

  const { mutateAsync: signFieldWithToken, isLoading: isSignFieldWithTokenLoading } =
    trpc.field.signFieldWithToken.useMutation(DO_NOT_INVALIDATE_QUERY_ON_MUTATION);

  const {
    mutateAsync: removeSignedFieldWithToken,
    isLoading: isRemoveSignedFieldWithTokenLoading,
  } = trpc.field.removeSignedFieldWithToken.useMutation(DO_NOT_INVALIDATE_QUERY_ON_MUTATION);

  const { Signature: signature } = field;

  const isLoading = isSignFieldWithTokenLoading || isRemoveSignedFieldWithTokenLoading || isPending;

  const [showSignatureModal, setShowSignatureModal] = useState(false);
  const [localSignature, setLocalSignature] = useState<string | null>(null);

  const state = useMemo<SignatureFieldState>(() => {
    if (!field.inserted) {
      return 'empty';
    }

    if (signature?.signatureImageAsBase64) {
      return 'signed-image';
    }

    return 'signed-text';
  }, [field.inserted, signature?.signatureImageAsBase64]);

  const onPreSign = () => {
    if (!providedSignature) {
      setShowSignatureModal(true);
      return false;
    }

    return true;
  };

  /**
   * When the user clicks the sign button in the dialog where they enter their signature.
   */
  const onDialogSignClick = () => {
    setShowSignatureModal(false);
    setProvidedSignature(localSignature);

    if (!localSignature) {
      return;
    }

    void executeActionAuthProcedure({
      onReauthFormSubmit: async (authOptions) => await onSign(authOptions, localSignature),
      actionTarget: field.type,
    });
  };

  const onSign = async (authOptions?: TRecipientActionAuth, signature?: string) => {
    try {
      const value = signature || providedSignature;

      if (!value) {
        setShowSignatureModal(true);
        return;
      }

      const payload: TSignFieldWithTokenMutationSchema = {
        token: recipient.token,
        fieldId: field.id,
        value,
        isBase64: true,
        authOptions,
      };

      if (onSignField) {
        await onSignField(payload);
        return;
      }

      await signFieldWithToken(payload);

      startTransition(() => router.refresh());
    } catch (err) {
      const error = AppError.parseError(err);

      if (error.code === AppErrorCode.UNAUTHORIZED) {
        throw error;
      }

      console.error(err);

      toast({
        title: 'Error',
        description: 'An error occurred while signing the document.',
        variant: 'destructive',
      });
    }
  };

  const onRemove = async () => {
    try {
      const payload: TRemovedSignedFieldWithTokenMutationSchema = {
        token: recipient.token,
        fieldId: field.id,
      };

      if (onUnsignField) {
        await onUnsignField(payload);
        return;
      }

      await removeSignedFieldWithToken(payload);

      startTransition(() => router.refresh());
    } catch (err) {
      console.error(err);

      toast({
        title: 'Error',
        description: 'An error occurred while removing the signature.',
        variant: 'destructive',
      });
    }
  };

  return (
    <SigningFieldContainer
      field={field}
      onPreSign={onPreSign}
      onSign={onSign}
      onRemove={onRemove}
      type="Signature"
    >
      {isLoading && (
        <div className="bg-background absolute inset-0 flex items-center justify-center rounded-md">
          <Loader className="text-primary h-5 w-5 animate-spin md:h-8 md:w-8" />
        </div>
      )}

      {state === 'empty' && (
        <p className="group-hover:text-primary font-signature text-muted-foreground text-lg duration-200 sm:text-xl md:text-2xl lg:text-3xl">
          Signature
        </p>
      )}

      {state === 'signed-image' && signature?.signatureImageAsBase64 && (
        <img
          src={signature.signatureImageAsBase64}
          alt={`Signature for ${recipient.name}`}
          className="h-full w-full object-contain dark:invert"
        />
      )}

      {state === 'signed-text' && (
        <p className="font-signature text-muted-foreground text-lg duration-200 sm:text-xl md:text-2xl lg:text-3xl">
          {/* This optional chaining is intentional, we don't want to move the check into the condition above */}
          {signature?.typedSignature}
        </p>
      )}

      <Dialog open={showSignatureModal} onOpenChange={setShowSignatureModal}>
        <DialogContent>
          <DialogTitle>
            Sign as {recipient.name}{' '}
            <span className="text-muted-foreground">({recipient.email})</span>
          </DialogTitle>

          <div className="">
            <Label htmlFor="signature">Signature</Label>

            <SignaturePad
              id="signature"
              className="border-border mt-2 h-44 w-full rounded-md border"
              onChange={(value) => setLocalSignature(value)}
            />
          </div>

          <SigningDisclosure />

          <DialogFooter>
            <div className="flex w-full flex-1 flex-nowrap gap-4">
              <Button
                type="button"
                className="dark:bg-muted dark:hover:bg-muted/80 flex-1  bg-black/5 hover:bg-black/10"
                variant="secondary"
                onClick={() => {
                  setShowSignatureModal(false);
                  setLocalSignature(null);
                }}
              >
                Cancel
              </Button>

              <Button
                type="button"
                className="flex-1"
                disabled={!localSignature}
                onClick={() => onDialogSignClick()}
              >
                Sign
              </Button>
            </div>
          </DialogFooter>
        </DialogContent>
      </Dialog>
    </SigningFieldContainer>
  );
};