[RSS] Replace scipy KDTree with Euclidean distance (#245)

* Replace scipy KDTree with Euclidean distance

* fixed star expression and missing import

* Version number

Co-authored-by: aikaterna <20862007+aikaterna@users.noreply.github.com>

rss/color.py

@@ -1,9 +1,70 @@
+from math import sqrt
 import discord
 import re
-from scipy.spatial import KDTree
 import webcolors
 
 
+_DISCORD_COLOURS = {
+    discord.Color.teal().to_rgb(): 'teal',
+    discord.Color.dark_teal().to_rgb(): 'dark_teal',
+    discord.Color.green().to_rgb(): 'green',
+    discord.Color.dark_green().to_rgb(): 'dark_green',
+    discord.Color.blue().to_rgb(): 'blue',
+    discord.Color.dark_blue().to_rgb(): 'dark_blue',
+    discord.Color.purple().to_rgb(): 'purple',
+    discord.Color.dark_purple().to_rgb(): 'dark_purple',
+    discord.Color.magenta().to_rgb(): 'magenta',
+    discord.Color.dark_magenta().to_rgb(): 'dark_magenta',
+    discord.Color.gold().to_rgb(): 'gold',
+    discord.Color.dark_gold().to_rgb(): 'dark_gold',
+    discord.Color.orange().to_rgb(): 'orange',
+    discord.Color.dark_orange().to_rgb(): 'dark_orange',
+    discord.Color.red().to_rgb(): 'red',
+    discord.Color.dark_red().to_rgb(): 'dark_red',
+    discord.Color.lighter_grey().to_rgb(): 'lighter_grey',
+    discord.Color.light_grey().to_rgb(): 'light_grey',
+    discord.Color.dark_grey().to_rgb(): 'dark_grey',
+    discord.Color.darker_grey().to_rgb(): 'darker_grey',
+    discord.Color.blurple().to_rgb(): 'old_blurple',
+    discord.Color(0x4a90e2).to_rgb(): 'new_blurple',
+    discord.Color.greyple().to_rgb(): 'greyple',
+    discord.Color.dark_theme().to_rgb(): 'discord_dark_theme'
+}
+
+_RGB_NAME_MAP = {webcolors.hex_to_rgb(hexcode): name for hexcode, name in webcolors.css3_hex_to_names.items()}
+_RGB_NAME_MAP.update(_DISCORD_COLOURS)
+
+
+def _distance(point_a: tuple, point_b: tuple):
+    """
+    Euclidean distance between two points using rgb values as the metric space.
+    """
+    # rgb values
+    x1, y1, z1 = point_a
+    x2, y2, z2 = point_b
+
+    # distances
+    dx = x1 - x2
+    dy = y1 - y2
+    dz = z1 - z2
+
+    # final distance
+    return sqrt(dx**2 + dy**2 + dz**2)
+
+def _linear_nearest_neighbour(all_points: list, pivot: tuple):
+    """
+    Check distance against all points from the pivot and return the distance and nearest point.
+    """
+    best_dist = None
+    nearest = None
+    for point in all_points:
+        dist = _distance(point, pivot)
+        if best_dist is None or dist < best_dist:
+            best_dist = dist
+            nearest = point
+    return best_dist, nearest
+
+
 class Color:
     """Helper for color handling."""
 
@@ -43,17 +104,10 @@ class Color:
         hex_code = await self._hex_validator(hex_code)
         rgb_tuple = await self._hex_to_rgb(hex_code)
 
-        names = []
-        positions = []
+        positions = list(_RGB_NAME_MAP.keys())
+        dist, nearest = _linear_nearest_neighbour(positions, rgb_tuple)
 
-        for hex, name in webcolors.css3_hex_to_names.items():
-            names.append(name)
-            positions.append(webcolors.hex_to_rgb(hex))
-
-        spacedb = KDTree(positions)
-        dist, index = spacedb.query(rgb_tuple)
-
-        return names[index]
+        return _RGB_NAME_MAP[nearest]
 
     async def _hex_to_rgb(self, hex_code: str):
         """

rss/info.json

@@ -5,6 +5,6 @@
     "description": "Read RSS feeds",
     "tags": ["rss"],
     "permissions": ["embed_links"],
-    "requirements": ["bs4", "feedparser>=6.0.0", "scipy", "webcolors==1.3"],
+    "requirements": ["bs4", "feedparser>=6.0.0", "webcolors==1.3"],
     "min_bot_version" : "3.4.0"
 }

rss/rss.py

@@ -25,7 +25,7 @@ from .tag_type import INTERNAL_TAGS, VALID_IMAGES, TagType
 log = logging.getLogger("red.aikaterna.rss")
 
 
-__version__ = "1.4.5"
+__version__ = "1.5.0"
 
 
 class RSS(commands.Cog):