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_calc.py

@@ -0,0 +1,114 @@
+"""
+Direct test of dose calculation functionality.
+"""
+
+import pandas as pd
+import pytest
+
+
+def calculate_daily_dose(dose_str: str) -> float:
+    """Calculate total daily dose from dose string format - copied from GraphManager."""
+    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
+
+
+class TestDoseCalculation:
+    """Test dose calculation functionality."""
+
+    def test_standard_format(self):
+        """Test dose calculation with standard timestamp:dose format."""
+        # Single dose
+        dose_str = "2025-07-28 18:59:45:150mg"
+        assert calculate_daily_dose(dose_str) == 150.0
+
+        # Multiple doses
+        dose_str = "2025-07-28 18:59:45:150mg|2025-07-28 19:34:19:75mg"
+        assert calculate_daily_dose(dose_str) == 225.0
+
+    def test_with_symbols(self):
+        """Test dose calculation with bullet symbols."""
+        # With bullet symbols
+        dose_str = "• • • • 2025-07-30 07:50:00:300"
+        assert calculate_daily_dose(dose_str) == 300.0
+
+    def test_decimal_values(self):
+        """Test dose calculation with decimal values."""
+        # Decimal dose
+        dose_str = "2025-07-28 18:59:45:12.5mg"
+        assert calculate_daily_dose(dose_str) == 12.5
+
+        # Multiple decimal doses
+        dose_str = "2025-07-28 18:59:45:12.5mg|2025-07-28 19:34:19:7.5mg"
+        assert calculate_daily_dose(dose_str) == 20.0
+
+    def test_no_timestamp_format(self):
+        """Test dose calculation without timestamps."""
+        # Simple dose without timestamp
+        dose_str = "100mg|50mg"
+        assert calculate_daily_dose(dose_str) == 150.0
+
+    def test_mixed_format(self):
+        """Test dose calculation with mixed formats."""
+        # Mixed format
+        dose_str = "• 2025-07-30 22:50:00:10|75mg"
+        assert calculate_daily_dose(dose_str) == 85.0
+
+    def test_edge_cases(self):
+        """Test dose calculation with edge cases."""
+        # Empty string
+        assert calculate_daily_dose("") == 0.0
+
+        # NaN value
+        assert calculate_daily_dose("nan") == 0.0
+
+        # No units
+        dose_str = "2025-07-28 18:59:45:10|2025-07-28 19:34:19:5"
+        assert calculate_daily_dose(dose_str) == 15.0
+
+    def test_malformed_data(self):
+        """Test dose calculation with malformed data."""
+        # Malformed data
+        assert calculate_daily_dose("malformed:data") == 0.0
+        assert calculate_daily_dose("::::") == 0.0
+        assert calculate_daily_dose("2025-07-28:") == 0.0
+        assert calculate_daily_dose("2025-07-28::mg") == 0.0
+
+    def test_partial_data(self):
+        """Test dose calculation with partial data."""
+        # No units but valid dose
+        assert calculate_daily_dose("2025-07-28 18:59:45:150") == 150.0
+
+
+if __name__ == "__main__":
+    pytest.main([__file__, "-v"])