Feat/auto persona colors (#23)

* add auto-generated persona colors based on name hash.

* updated color picker to use the colorhash package.

* comment out current persona colors to test auto generation.

* removed unused import.

* Added auto_color and lucide_icons tests to CI pytest command.

* uncommented the manually selected colors for the 10 phd advisor personas.

* Apply suggestion from @NeonDaniel

---------

Co-authored-by: Daniel McKnight <34697904+NeonDaniel@users.noreply.github.com>

.github/workflows/unit_tests.yml

@@ -27,7 +27,7 @@ jobs:
       - name: Run unit tests
         working-directory: multi_llm_chatbot_backend
         run: |
-          pytest app/tests/test_persona_config.py --junitxml=test-results/results.xml
+          pytest app/tests/test_persona_config.py app/tests/test_auto_colors.py app/tests/test_lucide_icons.py --junitxml=test-results/results.xml
 
       - name: Upload test results
         if: always()

multi_llm_chatbot_backend/app/config.py

@@ -9,8 +9,10 @@ working.
 
 import os
 import logging
+import colorsys
 from pathlib import Path
 from typing import List, Optional
+from colorhash import ColorHash
 
 import yaml
 from pydantic import BaseModel, validator, Field, model_validator
@@ -88,14 +90,24 @@ class PersonaItemConfig(_IconValidatorMixin):
     enabled: bool = True
     role: str = ""
     summary: str = ""
-    color: str = "#6B7280"
-    bg_color: str = "#F3F4F6"
-    dark_color: str = "#9CA3AF"
-    dark_bg_color: str = "#374151"
+    color: Optional[str] = None
+    bg_color: Optional[str] = None
+    dark_color: Optional[str] = None
+    dark_bg_color: Optional[str] = None
     icon: str = "HelpCircle"
     temperature: int = 5
     persona_prompt: str = ""
 
+    @model_validator(mode='after')
+    def _auto_generate_colors(self):
+        if self.color is None:
+            generated = generate_persona_colors(self.name)
+            self.color = generated["color"]
+            self.bg_color = generated["bg_color"]
+            self.dark_color = generated["dark_color"]
+            self.dark_bg_color = generated["dark_bg_color"]
+        return self
+
     def to_frontend_config(self) -> dict:
         return {
             "id": self.id,
@@ -293,7 +305,7 @@ def get_settings() -> AppSettings:
 
 
 # ---------------------------------------------------------------------------
-# Personas loader from directory
+# Helper Functions
 # ---------------------------------------------------------------------------
 
 
@@ -346,4 +358,23 @@ def load_personas_from_dir(personas_dir: str) -> List[PersonaItemConfig]:
         personas.append(persona)
 
     logger.info(f"Loaded {len(personas)} persona(s) from {personas_dir}")
-    return personas
+    return personas
+
+
+def generate_persona_colors(name: str) -> dict:
+    """Deterministically generate four theme colors from a persona name."""
+
+    ch = ColorHash(name.lower(), lightness=[0.55], saturation=[0.65])
+    hue = ch.hsl[0]  # grab the hue colorhash picked
+    h = hue / 360
+
+    def hsl_to_hex(h, s, l):
+        r, g, b = colorsys.hls_to_rgb(h, l, s)
+        return f"#{int(r*255):02X}{int(g*255):02X}{int(b*255):02X}"
+
+    return {
+        "color":         hsl_to_hex(h, 0.65, 0.55),
+        "bg_color":      hsl_to_hex(h, 0.60, 0.95),
+        "dark_color":    hsl_to_hex(h, 0.70, 0.70),
+        "dark_bg_color": hsl_to_hex(h, 0.65, 0.25),
+    }

multi_llm_chatbot_backend/app/tests/test_auto_colors.py

@@ -0,0 +1,42 @@
+import re
+import pytest
+from app.config import PersonaItemConfig, generate_persona_colors
+
+
+HEX_COLOR_RE = re.compile(r"^#[0-9A-Fa-f]{6}$")
+
+
+def _perceived_lightness(hex_color: str) -> float:
+    """0.0 = black, 1.0 = white. Weighted formula matching human perception."""
+    h = hex_color.lstrip("#")
+    r, g, b = (int(h[i:i+2], 16) for i in (0, 2, 4))
+    return (0.299 * r + 0.587 * g + 0.114 * b) / 255
+
+
+# ---------------------------------------------------------------------------
+# generate_persona_colors tests
+# ---------------------------------------------------------------------------
+
+
+def test_all_values_are_valid_hex():
+    colors = generate_persona_colors("Methodologist")
+    for key in ("color", "bg_color", "dark_color", "dark_bg_color"):
+        assert key in colors, f"Missing key: {key}"
+        assert HEX_COLOR_RE.match(colors[key]), f"{key}={colors[key]} is not valid hex"
+
+
+def test_deterministic():
+    a = generate_persona_colors("Methodologist")
+    b = generate_persona_colors("Methodologist")
+    assert a == b
+
+
+def test_bg_color_is_light_and_dark_bg_is_dark():
+    colors = generate_persona_colors("Methodologist")
+    assert _perceived_lightness(colors["bg_color"]) > 0.85
+    assert _perceived_lightness(colors["dark_bg_color"]) < 0.35
+
+
+def test_explicit_color_preserved():
+    p = PersonaItemConfig(id="test", name="Methodologist", color="#FF0000")
+    assert p.color == "#FF0000"

multi_llm_chatbot_backend/requirements.txt

@@ -15,6 +15,9 @@ python-docx
 python-dotenv
 pyyaml~=6.0
 
+# Persona color generation
+colorhash~=2.3
+
 # Vector database and embeddings
 chromadb
 sentence-transformers