Generating images using background tasks

--- 
+++ 
@@ -1,8 +1,10 @@
 import logging
+from json import JSONDecodeError

 import httpx
-
+from databases import Database
 from storeapi.config import config
+from storeapi.database import post_table

 logger = logging.getLogger(__name__)

@@ -46,3 +48,68 @@
             f" following link: {confirmation_url}"
         ),
     )
+
+
+async def _generate_cute_creature_api(prompt: str):
+    logger.debug("Generating cute creature")
+    async with httpx.AsyncClient() as client:
+        try:
+            response = await client.post(
+                "https://api.deepai.org/api/cute-creature-generator",
+                data={"text": prompt},
+                headers={"api-key": config.DEEPAI_API_KEY},
+                timeout=60,
+            )
+            logger.debug(response)
+            response.raise_for_status()
+            return response.json()
+        except httpx.HTTPStatusError as err:
+            raise APIResponseError(
+                f"API request failed with status code {err.response.status_code}"
+            ) from err
+        except (JSONDecodeError, TypeError) as err:
+            raise APIResponseError("API response parsing failed") from err
+
+
+async def generate_and_add_to_post(
+    email: str,
+    post_id: int,
+    post_url: str,
+    database: Database,
+    prompt: str = "A blue british shorthair cat is sitting on a couch",
+):
+    try:
+        response = await _generate_cute_creature_api(prompt)
+    except APIResponseError:
+        return await send_simple_email(
+            email,
+            "Error generating image",
+            (
+                f"Hi {email}! Unfortunately there was an error generating an image"
+                "for your post."
+            ),
+        )
+
+    logger.debug("Connecting to database to update post")
+
+    query = (
+        post_table.update()
+        .where(post_table.c.id == post_id)
+        .values(image_url=response["output_url"])
+    )
+
+    logger.debug(query)
+
+    await database.execute(query)
+
+    logger.debug("Database connection in background task closed")
+
+    await send_simple_email(
+        email,
+        "Image generation completed",
+        (
+            f"Hi {email}! Your image has been generated and added to your post."
+            f" Please click on the following link to view it: {post_url}"
+        ),
+    )
+    return response

--- 
+++ 
@@ -1,7 +1,13 @@
 import httpx
 import pytest
-
-from storeapi.tasks import APIResponseError, send_simple_email
+from databases import Database
+from storeapi.database import database, post_table
+from storeapi.tasks import (
+    APIResponseError,
+    _generate_cute_creature_api,
+    generate_and_add_to_post,
+    send_simple_email,
+)


 @pytest.mark.anyio
@@ -18,3 +24,60 @@

     with pytest.raises(APIResponseError):
         await send_simple_email("test@example.net", "Test Subject", "Test Body")
+
+
+@pytest.mark.anyio
+async def test_generate_cute_creature_api_success(mock_httpx_client):
+    json_data = {"output_url": "https://example.com/image.jpg"}
+
+    mock_httpx_client.post.return_value = httpx.Response(
+        status_code=200, json=json_data, request=httpx.Request("POST", "//")
+    )
+
+    result = await _generate_cute_creature_api("A cat")
+
+    assert result == json_data
+
+
+@pytest.mark.anyio
+async def test_generate_cute_creature_api_server_error(mock_httpx_client):
+    mock_httpx_client.post.return_value = httpx.Response(
+        status_code=500, content="", request=httpx.Request("POST", "//")
+    )
+
+    with pytest.raises(
+        APIResponseError, match="API request failed with status code 500"
+    ):
+        await _generate_cute_creature_api("A cat")
+
+
+@pytest.mark.anyio
+async def test_generate_cute_creature_api_json_error(mock_httpx_client):
+    mock_httpx_client.post.return_value = httpx.Response(
+        status_code=200, content="Not JSON", request=httpx.Request("POST", "//")
+    )
+
+    with pytest.raises(APIResponseError, match="API response parsing failed"):
+        await _generate_cute_creature_api("A cat")
+
+
+@pytest.mark.anyio
+async def test_generate_and_add_to_post_success(
+    mock_httpx_client, created_post: dict, confirmed_user: dict, db: Database
+):
+    json_data = {"output_url": "https://example.com/image.jpg"}
+
+    mock_httpx_client.post.return_value = httpx.Response(
+        status_code=200, json=json_data, request=httpx.Request("POST", "//")
+    )
+
+    await generate_and_add_to_post(
+        confirmed_user["email"], created_post["id"], "/post/1", db, "A cat"
+    )
+
+    # Check that after the background task runs, the post has been updated
+    query = post_table.select().where(post_table.c.id == created_post["id"])
+
+    updated_post = await database.fetch_one(query)
+
+    assert updated_post.image_url == json_data["output_url"]