Tag functionality added

backend/app/services/link_service.py

@@ -4,9 +4,71 @@ from uuid import uuid4
 from backend.app.core.security import clean_url
 from backend.app.database import get_connection
 
+MAX_TAGS = 10
 
-def create_link(user_id: str, title: str, url: str, comment: str, timestamp: str | None):
+
+def normalize_tags(tags: list[str] | None) -> list[str]:
+    normalized = []
+    normalized_keys = set()
+    for tag in tags or []:
+        value = tag.strip()
+        if value and not value.startswith('#'):
+            value = f'#{value}'
+        key = value.casefold()
+        if value and key not in normalized_keys:
+            normalized.append(value)
+            normalized_keys.add(key)
+    if len(normalized) > MAX_TAGS:
+        raise ValueError(f'A link can have at most {MAX_TAGS} tags')
+    return normalized
+
+
+def save_link_tags(conn, link_id: str, tags: list[str]) -> None:
+    canonical_tags = []
+    for tag in tags:
+        tag_row = conn.execute(
+            'SELECT id FROM tags WHERE lower(name) = lower(?)',
+            (tag,),
+        ).fetchone()
+        if tag_row is None:
+            conn.execute(
+                'INSERT INTO tags (id, name) VALUES (?, ?)',
+                (str(uuid4()), tag),
+            )
+            tag_row = conn.execute('SELECT id FROM tags WHERE name = ?', (tag,)).fetchone()
+        conn.execute(
+            'INSERT OR IGNORE INTO link_tags (link_id, tag_id) VALUES (?, ?)',
+            (link_id, tag_row['id']),
+        )
+        canonical_tags.append(conn.execute(
+            'SELECT name FROM tags WHERE id = ?',
+            (tag_row['id'],),
+        ).fetchone()['name'])
+    return canonical_tags
+
+
+def get_link_tags(conn, link_id: str) -> list[str]:
+    rows = conn.execute(
+        '''
+        SELECT tags.name FROM tags
+        JOIN link_tags ON link_tags.tag_id = tags.id
+        WHERE link_tags.link_id = ? ORDER BY tags.name
+        ''',
+        (link_id,),
+    ).fetchall()
+    return [row['name'] for row in rows]
+
+
+def create_link(
+    user_id: str,
+    title: str,
+    url: str,
+    comment: str,
+    timestamp: str | None,
+    tags: list[str] | None = None,
+):
     cleaned_url = clean_url(url)
+    normalized_tags = normalize_tags(tags)
     created_at = datetime.now(timezone.utc).isoformat()
     record = {
         'id': str(uuid4()),
@@ -37,7 +99,9 @@ def create_link(user_id: str, title: str, url: str, comment: str, timestamp: str
                 record['is_public'],
             ),
         )
+        stored_tags = save_link_tags(conn, record['id'], normalized_tags)
         conn.commit()
+    record['tags'] = stored_tags
     return record
 
 
@@ -54,11 +118,22 @@ def list_public_links(username: str | None = None):
             ''',
             (username, username),
         ).fetchall()
-    return [dict(row) for row in rows]
+        records = [dict(row) for row in rows]
+        for record in records:
+            record['tags'] = get_link_tags(conn, record['id'])
+    return records
 
 
-def update_link(link_id: str, user_id: str, title: str, url: str, comment: str):
+def update_link(
+    link_id: str,
+    user_id: str,
+    title: str,
+    url: str,
+    comment: str,
+    tags: list[str] | None = None,
+):
     cleaned_url = clean_url(url)
+    normalized_tags = normalize_tags(tags)
     with get_connection() as conn:
         cursor = conn.execute(
             '''
@@ -70,9 +145,13 @@ def update_link(link_id: str, user_id: str, title: str, url: str, comment: str):
         )
         if cursor.rowcount == 0:
             return None
+        conn.execute('DELETE FROM link_tags WHERE link_id = ?', (link_id,))
+        stored_tags = save_link_tags(conn, link_id, normalized_tags)
         conn.commit()
         row = conn.execute('SELECT * FROM links WHERE id = ?', (link_id,)).fetchone()
-    return dict(row)
+        record = dict(row)
+        record['tags'] = stored_tags
+    return record
 
 
 def list_public_users():
@@ -81,3 +160,15 @@ def list_public_users():
             'SELECT username FROM users ORDER BY username'
         ).fetchall()
     return [row['username'] for row in rows]
+
+
+def list_tags():
+    with get_connection() as conn:
+        rows = conn.execute('SELECT name FROM tags ORDER BY name').fetchall()
+    tags = []
+    seen = set()
+    for row in rows:
+        if row['name'].casefold() not in seen:
+            tags.append(row['name'])
+            seen.add(row['name'].casefold())
+    return tags