channels: add PUT /api/v6/:chan_id/permissions/:overwrite_id

This finishes the basics on channel overwrites.

SQL for instances:
```sql
DROP TABLE channel_overwrites;
```
Then run `schema.sql`.

 - channels: finish implementations for update_{text,voice}_channel
 - storage: fix _overwrite_convert
 - schema.sql: use unique constraint instead of primary key in
    channel_overwrites

litecord/blueprints/channels.py

@@ -7,7 +7,7 @@ from litecord.auth import token_check
 from litecord.enums import ChannelType, GUILD_CHANS
 from litecord.errors import ChannelNotFound
 from litecord.schemas import (
-    validate, CHAN_UPDATE
+    validate, CHAN_UPDATE, CHAN_OVERWRITE
 )
 
 from litecord.blueprints.checks import channel_check, channel_perm_check
@@ -231,6 +231,63 @@ async def _mass_chan_update(guild_id, channel_ids: int):
             'guild', guild_id, 'CHANNEL_UPDATE', chan)
 
 
+async def _process_overwrites(channel_id: int, overwrites: list):
+    for overwrite in overwrites:
+
+        # 0 for user overwrite, 1 for role overwrite
+        target_type = 0 if overwrite['type'] == 'user' else 1
+        target_role = None if target_type == 0 else overwrite['id']
+        target_user = overwrite['id'] if target_type == 0 else None
+
+        await app.db.execute(
+            """
+            INSERT INTO channel_overwrites
+                (channel_id, target_type, target_role,
+                target_user, allow, deny)
+            VALUES
+                ($1, $2, $3, $4, $5, $6)
+            ON CONFLICT ON CONSTRAINT channel_overwrites_uniq
+            DO
+            UPDATE
+                SET allow = $5, deny = $6
+                WHERE channel_overwrites.channel_id = $1
+                  AND channel_overwrites.target_type = $2
+                  AND channel_overwrites.target_role = $3
+                  AND channel_overwrites.target_user = $4
+            """,
+            channel_id, target_type,
+            target_role, target_user,
+            overwrite['allow'], overwrite['deny'])
+
+
+@bp.route('/<int:channel_id>/permissions/<int:overwrite_id>', methods=['PUT'])
+async def put_channel_overwrite(channel_id: int, overwrite_id: int):
+    """Insert or modify a channel overwrite."""
+    user_id = await token_check()
+    ctype, guild_id = await channel_check(user_id, channel_id)
+
+    if ctype not in GUILD_CHANS:
+        raise ChannelNotFound('Only usable for guild channels.')
+
+    await channel_perm_check(user_id, guild_id, 'manage_roles')
+
+    j = validate(
+        # inserting a fake id on the payload so validation passes through
+        {**await request.get_json(), **{'id': -1}},
+        CHAN_OVERWRITE
+    )
+
+    await _process_overwrites(channel_id, [{
+        'allow': j['allow'],
+        'deny': j['deny'],
+        'type': j['type'],
+        'id': overwrite_id
+    }])
+
+    await _mass_chan_update(guild_id, [channel_id])
+    return '', 204
+
+
 async def _update_channel_common(channel_id, guild_id: int, j: dict):
     if 'name' in j:
         await app.db.execute("""
@@ -282,13 +339,47 @@ async def _update_channel_common(channel_id, guild_id: int, j: dict):
         # since theres now an empty slot, move current channel to it
         await _update_pos(channel_id, new_pos)
 
+    if 'channel_overwrites' in j:
+        overwrites = j['channel_overwrites']
+        await _process_overwrites(channel_id, overwrites)
+
+
+async def _common_guild_chan(channel_id, j: dict):
+    # common updates to the guild_channels table
+    for field in [field for field in j.keys()
+                  if field in ('nsfw', 'parent_id')]:
+        await app.db.execute(f"""
+        UPDATE guild_channels
+        SET {field} = $1
+        WHERE id = $2
+        """, j[field], channel_id)
+
 
 async def _update_text_channel(channel_id: int, j: dict):
-    pass
+    # first do the specific ones related to guild_text_channels
+    for field in [field for field in j.keys()
+                  if field in ('topic', 'rate_limit_per_user')]:
+        await app.db.execute(f"""
+        UPDATE guild_text_channels
+        SET {field} = $1
+        WHERE id = $2
+        """, j[field], channel_id)
+
+    await _common_guild_chan(channel_id, j)
 
 
 async def _update_voice_channel(channel_id: int, j: dict):
-    pass
+    # first do the specific ones in guild_voice_channels
+    for field in [field for field in j.keys()
+                  if field in ('bitrate', 'user_limit')]:
+        await app.db.execute(f"""
+        UPDATE guild_voice_channels
+        SET {field} = $1
+        WHERE id = $2
+        """, j[field], channel_id)
+
+    # yes, i'm letting voice channels have nsfw, you cant stop me
+    await _common_guild_chan(channel_id, j)
 
 
 @bp.route('/<int:channel_id>', methods=['PUT', 'PATCH'])

litecord/schemas.py

@@ -252,13 +252,10 @@ GUILD_UPDATE = {
 
 
 CHAN_OVERWRITE = {
-    'type': 'dict',
-    'schema': {
-        'id': {'coerce': int},
-        'type': {'type': 'string', 'allowed': ['role', 'member']},
-        'allow': {'coerce': Permissions},
-        'deny': {'coerce': Permissions}
-    }
+    'id': {'coerce': int},
+    'type': {'type': 'string', 'allowed': ['role', 'member']},
+    'allow': {'coerce': Permissions},
+    'deny': {'coerce': Permissions}
 }
 
 
@@ -292,7 +289,7 @@ CHAN_UPDATE = {
 
     'permission_overwrites': {
         'type': 'list',
-        'schema': CHAN_OVERWRITE,
+        'schema': {'type': 'dict', 'schema': CHAN_OVERWRITE},
         'required': False
     },
 

litecord/storage.py

@@ -324,18 +324,20 @@ class Storage:
 
         def _overwrite_convert(row):
             drow = dict(row)
-            drow['type'] = drow['target_type']
+
+            target_type = drow['target_type']
+            drow['type'] = 'user' if target_type == 0 else 'role'
 
             # if type is 0, the overwrite is for a user
             # if type is 1, the overwrite is for a role
             drow['id'] = {
                 0: drow['target_user'],
                 1: drow['target_role'],
-            }[drow['type']]
+            }[target_type]
 
             drow['id'] = str(drow['id'])
 
-            drow.pop('overwrite_type')
+            drow.pop('target_type')
             drow.pop('target_user')
             drow.pop('target_role')
 

schema.sql

@@ -347,11 +347,15 @@ CREATE TABLE IF NOT EXISTS channel_overwrites (
     -- they're bigints (64bits), discord,
     -- for now, only needs 53.
     allow bigint DEFAULT 0,
-    deny bigint DEFAULT 0,
-
-    PRIMARY KEY (channel_id, target_role, target_user)
+    deny bigint DEFAULT 0
 );
 
+-- columns in private keys can't have NULL values,
+-- so instead we use a custom constraint with UNIQUE
+
+ALTER TABLE channel_overwrites ADD CONSTRAINT channel_overwrites_uniq
+    UNIQUE (channel_id, target_role, target_user);
+
 
 CREATE TABLE IF NOT EXISTS features (
     id serial PRIMARY KEY,