From 29a73c3c477b5207fd838252e7f8a3c6b360cc23 Mon Sep 17 00:00:00 2001
From: Tim Van Baak <tim.vanbaak@gmail.com>
Date: Tue, 1 Jun 2021 18:47:03 -0700
Subject: [PATCH] Add article backend

---
 amanuensis/backend/article.py | 62 +++++++++++++++++++++++++++++++++++
 tests/test_article.py         | 53 ++++++++++++++++++++++++++++++
 2 files changed, 115 insertions(+)
 create mode 100644 amanuensis/backend/article.py
 create mode 100644 tests/test_article.py

diff --git a/amanuensis/backend/article.py b/amanuensis/backend/article.py
new file mode 100644
index 0000000..932f70b
--- /dev/null
+++ b/amanuensis/backend/article.py
@@ -0,0 +1,62 @@
+"""
+Article query interface
+"""
+
+from sqlalchemy import select
+
+from amanuensis.db import *
+from amanuensis.errors import ArgumentError
+
+
+def create(
+    db: DbContext,
+    lexicon_id: int,
+    user_id: int,
+    character_id: int) -> Article:
+    """
+    Create a new article in a lexicon.
+    """
+    # Verify argument types are correct
+    if not isinstance(lexicon_id, int):
+        raise ArgumentError('lexicon_id')
+    if not isinstance(user_id, int):
+        raise ArgumentError('user_id')
+    if character_id is not None and not isinstance(character_id, int):
+        raise ArgumentError('character_id')
+
+    # Check that the user is a member of this lexicon
+    mem: Membership = db(
+        select(Membership)
+        .where(Membership.user_id == user_id)
+        .where(Membership.lexicon_id == lexicon_id)
+    ).scalar_one_or_none()
+    if not mem:
+        raise ArgumentError('User is not a member of lexicon')
+
+    # If the character id is provided, check that the user owns the character
+    # and the character belongs to the lexicon
+    if character_id is not None:
+        character: Character = db(
+            select(Character)
+            .where(Character.id == character_id)
+        ).scalar_one_or_none()
+        if not character:
+            raise ArgumentError('Character does not exist')
+        if character.user.id != user_id:
+            raise ArgumentError('Character is owned by the wrong player')
+        if character.lexicon.id != lexicon_id:
+            raise ArgumentError('Character belongs to the wrong lexicon')
+        signature = character.signature
+    else:
+        signature = '~Ersatz Scrivener'
+
+    new_article = Article(
+        lexicon_id=lexicon_id,
+        user_id=user_id,
+        character_id=character_id,
+        title='Article title',
+        body=f'\n\n{signature}',
+    )
+    db.session.add(new_article)
+    db.session.commit()
+    return new_article
diff --git a/tests/test_article.py b/tests/test_article.py
new file mode 100644
index 0000000..8b7b6cf
--- /dev/null
+++ b/tests/test_article.py
@@ -0,0 +1,53 @@
+import pytest
+
+from amanuensis.db import DbContext
+import amanuensis.backend.article as artiq
+
+from amanuensis.errors import ArgumentError
+
+
+def test_create_article(db: DbContext, make):
+    """Test new article creation"""
+    # Create two users in a shared lexicon
+    user1 = make.user()
+    user2 = make.user()
+    lexicon1 = make.lexicon()
+    make.membership(user_id=user1.id, lexicon_id=lexicon1.id)
+    make.membership(user_id=user2.id, lexicon_id=lexicon1.id)
+    char1_1 = make.character(lexicon_id=lexicon1.id, user_id=user1.id)
+    char1_2 = make.character(lexicon_id=lexicon1.id, user_id=user2.id)
+
+    # Create a lexicon that only one user is in
+    lexicon2 = make.lexicon()
+    make.membership(user_id=user2.id, lexicon_id=lexicon2.id)
+    char2_2 = make.character(lexicon_id=lexicon2.id, user_id=user2.id)
+
+    # User cannot create article for another user's character
+    with pytest.raises(ArgumentError):
+        artiq.create(db, lexicon1.id, user1.id, char1_2.id)
+    with pytest.raises(ArgumentError):
+        artiq.create(db, lexicon1.id, user2.id, char1_1.id)
+
+    # User cannot create article for their character in the wrong lexicon
+    with pytest.raises(ArgumentError):
+        artiq.create(db, lexicon1.id, user2.id, char2_2.id)
+    with pytest.raises(ArgumentError):
+        artiq.create(db, lexicon2.id, user2.id, char1_2.id)
+
+    # User cannot create article in a lexicon they aren't in
+    with pytest.raises(ArgumentError):
+        artiq.create(db, lexicon2.id, user1.id, char1_1.id)
+
+    # User cannot create anonymous articles in a lexicon they aren't in
+    with pytest.raises(ArgumentError):
+        artiq.create(db, lexicon2.id, user1.id, character_id=None)
+
+    # Users can create character-owned articles
+    assert artiq.create(db, lexicon1.id, user1.id, char1_1.id)
+    assert artiq.create(db, lexicon1.id, user2.id, char1_2.id)
+    assert artiq.create(db, lexicon2.id, user2.id, char2_2.id)
+
+    # Users can create anonymous articles
+    assert artiq.create(db, lexicon1.id, user1.id, character_id=None)
+    assert artiq.create(db, lexicon1.id, user2.id, character_id=None)
+    assert artiq.create(db, lexicon2.id, user2.id, character_id=None)