feat: Implement dose calculation fix and enhance legend feature

- Fixed dose calculation logic in `_calculate_daily_dose` to correctly parse timestamps with multiple colons.
- Added comprehensive test cases for various dose formats and edge cases in `test_dose_calculation.py`.
- Enhanced graph legend to display individual medicines with average dosages and track medicines without dose data.
- Updated legend styling and positioning for better readability and organization.
- Created new tests for enhanced legend functionality, including handling of medicines with and without data.
- Improved mocking for matplotlib components in tests to prevent TypeErrors.

scripts/test_dose_simple.py

@@ -0,0 +1,95 @@
+#!/usr/bin/env python3
+"""
+Simple test script to verify dose calculation functionality without GUI.
+"""
+
+import os
+import sys
+
+# Add the src directory to Python path
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), "src"))
+
+
+def calculate_daily_dose(dose_str: str) -> float:
+    """Calculate total daily dose from dose string format."""
+    import pandas as pd
+
+    if not dose_str or pd.isna(dose_str) or str(dose_str).lower() == "nan":
+        return 0.0
+
+    total_dose = 0.0
+    # Handle different separators and clean the string
+    dose_str = str(dose_str).replace("•", "").strip()
+
+    # Split by | or by spaces if no | present
+    dose_entries = dose_str.split("|") if "|" in dose_str else [dose_str]
+
+    for entry in dose_entries:
+        entry = entry.strip()
+        if not entry:
+            continue
+
+        try:
+            # Extract dose part after the last colon (timestamp:dose format)
+            dose_part = entry.split(":")[-1] if ":" in entry else entry
+
+            # Extract numeric part from dose (e.g., "150mg" -> 150)
+            dose_value = ""
+            for char in dose_part:
+                if char.isdigit() or char == ".":
+                    dose_value += char
+                elif dose_value:  # Stop at first non-digit after finding digits
+                    break
+
+            if dose_value:
+                total_dose += float(dose_value)
+        except (ValueError, IndexError):
+            continue
+
+    return total_dose
+
+
+def test_dose_calculation():
+    """Test the dose calculation method directly."""
+
+    # Test cases
+    test_cases = [
+        # (input, expected_output, description)
+        ("2025-07-28 18:59:45:150mg", 150.0, "Single dose with timestamp"),
+        ("2025-07-28 18:59:45:150mg|2025-07-28 19:34:19:75mg", 225.0, "Multiple doses"),
+        ("• • • • 2025-07-30 07:50:00:300", 300.0, "Dose with bullet symbols"),
+        ("2025-07-28 18:59:45:12.5mg|2025-07-28 19:34:19:7.5mg", 20.0, "Decimal doses"),
+        ("100mg|50mg", 150.0, "Doses without timestamps"),
+        ("• 2025-07-30 22:50:00:10|75mg", 85.0, "Mixed format"),
+        ("", 0.0, "Empty string"),
+        ("nan", 0.0, "NaN value"),
+        ("2025-07-28 18:59:45:10|2025-07-28 19:34:19:5", 15.0, "No units"),
+    ]
+
+    print("Testing dose calculation...")
+    all_passed = True
+
+    for input_str, expected, description in test_cases:
+        result = calculate_daily_dose(input_str)
+        passed = abs(result - expected) < 0.001  # Allow for floating point precision
+
+        status = "PASS" if passed else "FAIL"
+        print(f"{status}: {description}")
+        print(f"  Input: '{input_str}'")
+        print(f"  Expected: {expected}, Got: {result}")
+        print()
+
+        if not passed:
+            all_passed = False
+
+    if all_passed:
+        print("All dose calculation tests PASSED!")
+    else:
+        print("Some dose calculation tests FAILED!")
+
+    return all_passed
+
+
+if __name__ == "__main__":
+    success = test_dose_calculation()
+    sys.exit(0 if success else 1)