add functionality for people to block other users they don't want to interact with

.gitignore

@@ -1,4 +1,5 @@
 config.json
+blocks.json
 
 # ---> Python
 # Byte-compiled / optimized / DLL files

waggle-dance.py

@@ -4,20 +4,90 @@ import asyncio
 import discord
 import json
 import random
+import re
 import sys
 
+BLOCKS_FILE = 'blocks.json'
+
+def get_blocks():
+    try:
+        with open(BLOCKS_FILE) as f:
+            return {int(k): v for (k, v) in json.load(f).items()}
+    except FileNotFoundError:
+        return {}
+
+def add_block(requester, target):
+    blocks = get_blocks()
+    if requester not in blocks:
+        blocks[requester] = []
+    if target not in blocks[requester]:
+        blocks[requester].append(target)
+    with open(BLOCKS_FILE, 'w') as f:
+        json.dump(blocks, f)
+
+def remove_block(requester, target):
+    blocks = get_blocks()
+    if requester not in blocks:
+        return
+    while target in blocks[requester]:
+        blocks[requester].remove(target)
+    if len(blocks[requester]) == 0:
+        del blocks[requester]
+    with open(BLOCKS_FILE, 'w') as f:
+        json.dump(blocks, f)
+
 def matchings(l):
-    if len(l) == 0:
+    count = len(l)
+    if count == 0:
         return []
     l = l.copy()
     random.shuffle(l)
-    center = l.pop()
+    ids = set(u.id for u in l)
+
+    blocks = get_blocks()
+    block_pairs = set()
+    for r in blocks:
+        if r in ids:
+            for t in blocks[r]:
+                if t in ids:
+                    block_pairs.add((min(r,t), max(r,t)))
+    disjoint_pairs = []
+    while True:
+        paired = set(u for pair in disjoint_pairs for u in pair)
+        remaining = set(p for p in block_pairs if p[0] not in paired and p[1] not in paired)
+        if len(remaining) == 0:
+            break
+        disjoint_pairs.append(remaining.pop())
+
+    circle = [None]*(count - 1)
+    center = None
+    for i in range(count // 2):
+        if len(disjoint_pairs) != 0:
+            p = disjoint_pairs.pop()
+            l = [u for u in l if u.id not in p]
+            u0 = p[0]
+            u1 = p[1]
+        else:
+            u0 = l.pop()
+            u1 = l.pop()
+
+        circle[i] = u0
+        if i != count // 2 - 1:
+            circle[-(i+1)] = u1
+        else:
+            center = u1
+
     result = []
-    for i in range(len(l)):
-        matching = [(center, l[i])]
-        for j in range(1, (len(l)-1)//2 + 1):
-            matching.append((l[(i-j)%len(l)], l[(i+j)%len(l)]))
+    for i in range(len(circle)):
+        matching = [(center, circle[i])]
+        for j in range(1, (len(circle)-1)//2 + 1):
+            matching.append((circle[(i-j)%len(circle)], circle[(i+j)%len(circle)]))
         result.append(matching)
+
+    random.shuffle(result)
+    for i in range(len(result)):
+        random.shuffle(result[i])
+    result = [matching for matching in result if all((min(match[0].id,match[1].id), max(match[0].id,match[1].id)) not in block_pairs for match in matching)]
     return result
 
 async def delete_if_possible(channels):
@@ -39,15 +109,7 @@ with open('config.json') as f:
 
 client = discord.Client()
 
-@client.event
-async def on_ready():
-    print('logged in as {0.user}'.format(client), file=sys.stderr)
-
-@client.event
-async def on_message(message):
-    if message.author == client.user:
-        return
-
+async def handle_guild_message(message):
     if not message.content.startswith('!waggle'):
         return
 
@@ -81,10 +143,6 @@ async def on_message(message):
         participants.remove(message.author)
         await message.channel.send('leaving out {} so we have an even number of participants'.format(message.author.mention))
 
-    if len(participants) == 0:
-        await message.channel.send('there are no participants! :(')
-        return
-
     mention_all = ' '.join(u.mention for u in participants)
 
     schedule = matchings(participants)
@@ -92,6 +150,10 @@ async def on_message(message):
     if rounds:
         schedule = schedule[:rounds]
 
+    if len(schedule) == 0:
+        await message.channel.send("there aren't enough people for pollination right now :(")
+        return
+
     pollination_channels = []
     channel_names = config['channel_names'].copy()
     exception_count = 0
@@ -147,4 +209,44 @@ async def on_message(message):
 
     await delete_if_possible(pollination_channels)
 
+async def handle_dm(message):
+    requester = message.author.id
+    match = re.search('@([^#]+)#([0-9a-f]+)', message.content)
+    if match:
+        handle = match.group(0)
+        name = match.group(1)
+        discriminator = match.group(2)
+        matching_users = [u for u in client.users if u.name == name and u.discriminator == discriminator]
+        if len(matching_users) == 0:
+            await message.channel.send("sorry, I can't find user {}".format(handle))
+        else:
+            target = matching_users[0].id
+            if target in get_blocks().get(requester, []):
+                await message.channel.send("removing {} from your list of blocked users for pollination".format(handle))
+                remove_block(requester, target)
+            else:
+                await message.channel.send("adding {} to your list of blocked users for pollination".format(handle))
+                add_block(requester, target)
+
+    blocks = get_blocks().get(requester, [])
+    if len(blocks) == 0:
+        await message.channel.send("you currently don't have anyone blocked for pollination")
+    else:
+        await message.channel.send("your current list of blocked users for pollination is:\n{}".format('\n'.join('@{}#{}'.format(u.name, u.discriminator) for u in [client.get_user(uid) for uid in blocks] if u is not None)))
+    await message.channel.send("to block or unblock a user, DM me their handle, like @creep#0000. to see this message and your list of blocked users, DM me something random. buzz buzz!")
+
+@client.event
+async def on_ready():
+    print('logged in as {0.user}'.format(client), file=sys.stderr)
+
+@client.event
+async def on_message(message):
+    if message.author == client.user:
+        return
+
+    if isinstance(message.channel, discord.TextChannel):
+        await handle_guild_message(message)
+    elif isinstance(message.channel, discord.DMChannel):
+        await handle_dm(message)
+
 client.run(config['token'])