feat: creatives and external channels

src/usecase/external_channel/create_external_channel.py

@@ -0,0 +1,47 @@
+import logging
+import uuid
+from typing import TYPE_CHECKING
+
+from src import domain, dto
+
+if TYPE_CHECKING:
+    from .. import Usecase
+
+log = logging.getLogger(__name__)
+
+
+async def create_external_channel(
+    self: 'Usecase', input: dto.CreateExternalChannelInput, user_id: uuid.UUID
+) -> dto.ExternalChannelOutput:
+    async with self.database.transaction():
+        for target_id in input.target_channel_ids:
+            target_channel = await self.database.get_target_channel(user_id, channel_id=target_id)
+            if not target_channel:
+                log.warning('User %s attempted to add external channel to unavailable target %s', user_id, target_id)
+                raise domain.TargetChannelNotFound(target_id)
+
+        channel = domain.ExternalChannel(
+            telegram_id=input.telegram_id,
+            title=input.title,
+            username=input.username,
+            description=input.description,
+            subscribers_count=input.subscribers_count,
+            user_id=user_id,
+        )
+        created_channel = await self.database.create_external_channel(channel)
+
+        if input.target_channel_ids:
+            await self.database.add_external_channel_to_targets(created_channel.id, input.target_channel_ids)
+
+    log.info(
+        'External channel %s created and linked to %s target channels', input.telegram_id, len(input.target_channel_ids)
+    )
+
+    return dto.ExternalChannelOutput(
+        id=created_channel.id,
+        telegram_id=created_channel.telegram_id,
+        title=created_channel.title,
+        username=created_channel.username,
+        description=created_channel.description,
+        subscribers_count=created_channel.subscribers_count,
+    )