Add back and correct "resendoauthverification" command (#779)

* Revert "Remove one-time-use command (#768)"

This reverts commit c7ed810.

* Update resendoauthverifications command with corrections

* Add unit tests for valid email link

api/catalog/management/commands/resendoauthverification.py

@@ -0,0 +1,229 @@
+import argparse
+from dataclasses import dataclass
+
+from django.conf import settings
+from django.core.mail import send_mail
+from django.db import transaction
+from django.db.models import Q
+from rest_framework.reverse import reverse
+
+from django_redis import get_redis_connection
+from django_tqdm import BaseCommand
+
+from catalog.api.models.oauth import (
+    OAuth2Registration,
+    OAuth2Verification,
+    ThrottledApplication,
+)
+
+
+def get_input(text):
+    """
+    Wrapped ``input`` to allow patching in unittests
+    """
+    return input(text)
+
+
+verification_msg_template = """
+The Openverse API OAuth2 email verification process has recently been fixed.
+We have detected that you attempted to register an application using this email.
+
+To verify your Openverse API credentials, click on the following link:
+
+{link}
+
+We previously sent this message with an incorrectly formatted link.
+Apologies for the repeated contacts. If you believe you received this
+message in error or have already successfully verified your OAuth
+application, please disregard it.
+"""
+
+
+@dataclass
+class Result:
+    saved_application_name: str
+    deleted_applications: int
+    deleted_registrations: int
+    deleted_verifications: int
+
+
+class Command(BaseCommand):
+    help = "Resends verification emails for unverified Oauth applications."
+    """
+    This command sends a corrected oauth verification email to users who have
+    not yet verified their Openverse oauth applications. A previous version sent
+    an email with an incorrectly formatted link.
+
+    It stores a cache of successfully sent emails in Redis, so running it multiple
+    times (in case of failure) should not be an issue.
+    """
+
+    processed_key = "resendoauthverification-corrections:processed"
+
+    def add_arguments(self, parser):
+        parser.add_argument(
+            "--dry_run",
+            help="Count the records that will be removed but don't apply any changes.",
+            type=bool,
+            default=True,
+            action=argparse.BooleanOptionalAction,
+        )
+
+    @transaction.atomic
+    def _handle_email(self, email, dry):
+        """
+        1. Get all application IDs for the email
+        2. Use the one with the lowest ID as the "original" attempt
+        3. Delete the rest
+        4. Delete OAuth2Registrations for the email not associated
+            with the "original" application
+        5. Delete OAuth2Verifications for the email not associated
+            with the "original" application
+
+        This ignores the fact that someone could have tried to register
+        multiple unverified but distinct applications under the same email.
+        This is unlikely given that none of the requests would have worked
+        and that the "feature" isn't explicitly documented anyway.
+        """
+        application_ids = list(
+            OAuth2Registration.objects.filter(email=email)
+            .select_related("associated_application")
+            .order_by("id")
+            .values_list("pk", flat=True)
+        )
+
+        application_to_verify = ThrottledApplication.objects.get(pk=application_ids[0])
+
+        deleted_applications = 0
+        deleted_registrations = 0
+        deleted_verifications = 0
+        if len(application_ids) > 1:
+            applications_to_delete_ids = application_ids[1:]
+            deleted_applications = len(applications_to_delete_ids)
+            if not dry:
+                ThrottledApplication.objects.filter(
+                    pk__in=applications_to_delete_ids
+                ).delete()
+
+            registrations_to_delete = OAuth2Registration.objects.filter(
+                email=email
+            ).exclude(name=application_to_verify.name)
+            deleted_registrations = registrations_to_delete.count()
+            if not dry:
+                registrations_to_delete.delete()
+
+            verifications_to_delete = OAuth2Verification.objects.filter(
+                email=email
+            ).exclude(associated_application=application_to_verify)
+            deleted_verifications = verifications_to_delete.count()
+            if not dry:
+                verifications_to_delete.delete()
+
+        if not dry:
+            verification = OAuth2Verification.objects.get(
+                associated_application=application_to_verify
+            )
+            token = verification.code
+            # We don't have access to `request.build_absolute_uri` so we
+            # have to build it ourselves for the production endpoint
+            link = (
+                f"https://api.openverse.engineering{reverse('verify-email', [token])}"
+            )
+            verification_msg = verification_msg_template.format(link=link)
+            send_mail(
+                subject="Verify your API credentials (corrected)",
+                message=verification_msg,
+                from_email=settings.DEFAULT_FROM_EMAIL,
+                recipient_list=[verification.email],
+                fail_silently=False,
+            )
+
+        return Result(
+            saved_application_name=application_to_verify.name,
+            deleted_applications=deleted_applications,
+            deleted_registrations=deleted_registrations,
+            deleted_verifications=deleted_verifications,
+        )
+
+    def handle(self, *args, **options):
+        dry = options["dry_run"]
+        if not dry:
+            self.info(
+                self.style.WARNING(
+                    "This is NOT a dry run. Are you sure you wish to proceed? "
+                    "Respond 'yes' in all uppercase to proceed.\n"
+                )
+            )
+            if get_input(": ") != "YES":
+                self.error("Exiting.")
+                exit(1)
+
+        redis = get_redis_connection("default")
+
+        already_processed_emails = [
+            email.decode("utf-8") for email in redis.smembers(self.processed_key)
+        ]
+
+        emails_with_verified_applications = OAuth2Verification.objects.filter(
+            Q(associated_application__verified=True)
+            | Q(email__in=already_processed_emails)
+        ).values_list("email", flat=True)
+
+        emails_with_zero_verified_applications = list(
+            OAuth2Verification.objects.exclude(
+                email__in=emails_with_verified_applications
+            )
+            .values_list("email", flat=True)
+            .distinct()
+        )
+
+        count_to_process = len(emails_with_zero_verified_applications)
+        results = []
+        errored_emails = []
+
+        with self.tqdm(total=count_to_process) as progress:
+            for email in emails_with_zero_verified_applications:
+                try:
+                    results.append(self._handle_email(email, dry))
+                    if not dry:
+                        redis.sadd(self.processed_key, email)
+                except BaseException as err:
+                    errored_emails.append(email)
+                    self.error(f"Unable to process {email}: " f"{err}")
+
+                progress.update(1)
+
+        if errored_emails:
+            joined = "\n".join(errored_emails)
+            self.info(
+                self.style.WARNING(
+                    f"The following emails were unable to be processed.\n\n"
+                    f"{joined}"
+                    "\n\nPlease check the output above for the error related"
+                    "to each email."
+                )
+            )
+
+        formatted_results = "\n\n".join(
+            (
+                f"Application name: {result.saved_application_name}\n"
+                f"Cleaned related application count: {result.deleted_applications}\n"
+                f"Cleaned related verification count: {result.deleted_verifications}\n"
+                f"Cleaned related registration count: {result.deleted_registrations}\n"
+            )
+            for result in results
+        )
+
+        self.info(
+            self.style.SUCCESS(
+                f"The following applications had email verifications sent.\n\n"
+                f"{formatted_results}"
+            )
+        )
+
+        if dry:
+            self.info(
+                self.style.WARNING(
+                    "The above was a dry run and no records were actually affected."
+                )
+            )