Refactor BaseMetricService (#17)

backend/domain/services/__init__.py

@@ -1,14 +1,11 @@
 """Domain services package."""
-
-from .base import BaseMetricService
 from .abandoned_problems_service import AbandonedProblemsService
 from .daily_activity_service import DailyActivityService
 from .difficulty_distribution_service import DifficultyDistributionService
 from .tags_service import TagsService
 
 __all__ = [
     "AbandonedProblemsService",
-    "BaseMetricService",
     "DailyActivityService",
     "DifficultyDistributionService",
     "TagsService",

backend/domain/services/abandoned_problems_service.py

@@ -10,10 +10,9 @@
     TagAbandonedStats,
 )
 from backend.domain.models.codeforces import Submission
-from backend.domain.services.base import BaseMetricService
 
 
-class AbandonedProblemsService(BaseMetricService):
+class AbandonedProblemsService():
     """Service for analyzing abandoned problems (attempted but never solved)."""
 
     @staticmethod

backend/domain/services/base.py

@@ -1,42 +1,50 @@
+import copy
 from typing import List
-
 from backend.domain.models.codeforces import Submission
 
+class SubmissionCollection:
+    """Encapsulates submissions with filtering and deduplication operations."""
 
-class BaseMetricService:
-    """Base class for all metric services with shared functionality."""
-
-    @staticmethod
-    def _deduplicate_problems(submissions: List[Submission]) -> List[Submission]:
+    def __init__(self, submissions: List[Submission]):
+        """
+        Initialize an instance which contains original list of submissions.
+
+        Args:
+            submissions: List of user's submissions
+        """
+        self._submissions = submissions
+
+    def deduplicate_problems(self, submissions: List[Submission]=[]) -> List[Submission]:
         """
         Keep only the first successful solve for each unique problem.
 
         Args:
-            submissions: List of submissions to deduplicate
+            submissions: List of user's submissions to deduplicate
 
         Returns:
             List of submissions with only first solve per problem
         """
         seen_problems = set()
         unique_submissions = []
 
-        for submission in submissions:
+        # Preference given to submissions argument
+        submissions_copy = submissions if submissions else copy.copy(self._submissions)
+
+        for submission in submissions_copy:
             problem_key = submission.problem.problem_key
             if problem_key not in seen_problems:
                 seen_problems.add(problem_key)
                 unique_submissions.append(submission)
 
         return unique_submissions
 
-    @staticmethod
-    def _filter_successful_submissions(submissions: List[Submission]) -> List[Submission]:
+    def filter_successful_submissions(self) -> List[Submission]:
         """
         Filter submissions to only include solved problems.
 
-        Args:
-            submissions: List of all submissions
-
         Returns:
             List of only solved submissions
         """
-        return [s for s in submissions if s.is_solved]
+        submissions_copy = copy.copy(self._submissions)
+        successful_submissions = [s for s in submissions_copy if s.is_solved]
+        return successful_submissions

backend/domain/services/daily_activity_service.py

@@ -7,7 +7,6 @@
 from backend.domain.models.codeforces import Submission
 from backend.domain.models.daily_activity import DailyActivity, DailyActivityAnalysis
 from backend.domain.models.time_period import TimePeriod
-from backend.domain.services.base import BaseMetricService
 
 _GRANULARITY_MAP = {
     TimePeriod.HOUR: "minute",
@@ -61,7 +60,7 @@ def _advance(current: datetime, granularity: str) -> datetime:
     return current + _FIXED_STEPS[granularity]
 
 
-class DailyActivityService(BaseMetricService):
+class DailyActivityService():
     """Service for generating activity analytics with variable granularity."""
 
     @staticmethod

backend/domain/services/difficulty_distribution_service.py

@@ -8,10 +8,10 @@
     DifficultyDistribution,
     RatingRange,
 )
-from backend.domain.services.base import BaseMetricService
+from backend.domain.services.base import SubmissionCollection
 
 
-class DifficultyDistributionService(BaseMetricService):
+class DifficultyDistributionService():
     """Service for generating difficulty distribution analytics."""
 
     # Standard rating bins for Codeforces (100-point intervals)
@@ -61,9 +61,8 @@ def analyze_difficulty_distribution(
             DifficultyDistribution with analyzed data
         """
         # Filter successful submissions
-        successful_submissions = DifficultyDistributionService._filter_successful_submissions(
-            submissions
-        )
+        submission_collection = SubmissionCollection(submissions)
+        successful_submissions = submission_collection.filter_successful_submissions()
 
         if not successful_submissions:
             return DifficultyDistribution(
@@ -73,7 +72,7 @@ def analyze_difficulty_distribution(
             )
 
         # Remove duplicate problems (keep first solve)
-        unique_solves = DifficultyDistributionService._deduplicate_problems(successful_submissions)
+        unique_solves = submission_collection.deduplicate_problems(successful_submissions)
 
         # Group problems by rating bins
         bin_counts = DifficultyDistributionService._create_bin_distribution(unique_solves)

backend/domain/services/tags_service.py

@@ -6,10 +6,10 @@
 
 from backend.domain.models.codeforces import Submission
 from backend.domain.models.tags import TagInfo, TagsAnalysis
-from backend.domain.services.base import BaseMetricService
+from backend.domain.services.base import SubmissionCollection
 
 
-class TagsService(BaseMetricService):
+class TagsService():
     """Service for generating tags analytics."""
 
     @staticmethod
@@ -25,7 +25,8 @@ def analyze_tags(handle: str, submissions: List[Submission]) -> TagsAnalysis:
             TagsAnalysis with analyzed data
         """
         # Filter successful submissions
-        successful_submissions = TagsService._filter_successful_submissions(submissions)
+        submission_collection = SubmissionCollection(submissions)
+        successful_submissions = submission_collection.filter_successful_submissions()
 
         if not successful_submissions:
             return TagsAnalysis(
@@ -37,7 +38,7 @@ def analyze_tags(handle: str, submissions: List[Submission]) -> TagsAnalysis:
             )
 
         # Remove duplicate problems (keep first solve)
-        unique_solves = TagsService._deduplicate_problems(successful_submissions)
+        unique_solves = submission_collection.deduplicate_problems(successful_submissions)
 
         # Group problems by tags and calculate statistics
         tags_data, overall_ratings = TagsService._analyze_tags(unique_solves)

backend/tests/unit/base_metric_service/test_deduplicate_problems.py

@@ -1,4 +1,4 @@
-from backend.domain.services import BaseMetricService
+from backend.domain.services.base import SubmissionCollection
 
 
 def test_deduplicate_problems_happy_path(mock_submission):
@@ -20,11 +20,13 @@ def test_deduplicate_problems_happy_path(mock_submission):
         is_solved=True,
     )
 
-    result = BaseMetricService._deduplicate_problems([submission1, submission2])
+    submission_collection = SubmissionCollection([submission1, submission2])
+    result = submission_collection.deduplicate_problems()
     assert result == [submission1]
 
 def test_deduplicate_problems_empty_submissions_list(mock_submission):
-   result = BaseMetricService._deduplicate_problems([])
+   submission_collection = SubmissionCollection([])
+   result = submission_collection.deduplicate_problems()
    assert result == []
 
 def test_deduplicate_problems_single_submission(mock_submission):
@@ -37,7 +39,8 @@ def test_deduplicate_problems_single_submission(mock_submission):
        is_solved=False,
    )
 
-   result = BaseMetricService._deduplicate_problems([submission1])
+   submission_collection = SubmissionCollection([submission1])
+   result = submission_collection.deduplicate_problems()
 
    assert result == [submission1]
 
@@ -69,7 +72,8 @@ def test_deduplicate_problems_all_unique_submissions(mock_submission):
         is_solved=True,
     )
 
-    result = BaseMetricService._deduplicate_problems([submission1, submission2, submission3])
+    submission_collection = SubmissionCollection([submission1, submission2, submission3])
+    result = submission_collection.deduplicate_problems()
 
     assert result == [submission1, submission2, submission3]
 
@@ -101,7 +105,8 @@ def test_deduplicate_problems_multiple_duplicates(mock_submission):
         is_solved=False,
     )
 
-    result = BaseMetricService._deduplicate_problems([submission1, submission2, submission3])
+    submission_collection = SubmissionCollection([submission1, submission2, submission3])
+    result = submission_collection.deduplicate_problems()
 
     assert result == [submission1]
 
@@ -133,7 +138,8 @@ def test_deduplicate_problems_preserves_order(mock_submission):
         is_solved=False,
     )
 
-    result = BaseMetricService._deduplicate_problems([submission1, submission2, submission3])
+    submission_collection = SubmissionCollection([submission1, submission2, submission3])
+    result = submission_collection.deduplicate_problems()
 
     assert result == [submission1, submission2]
 
@@ -156,7 +162,8 @@ def test_deduplicate_problems_same_index_different_contest_id(mock_submission):
         is_solved=True,
     )
 
-    result = BaseMetricService._deduplicate_problems([submission1, submission2])
+    submission_collection = SubmissionCollection([submission1, submission2])
+    result = submission_collection.deduplicate_problems()
     assert result == [submission1, submission2]
 
 def test_deduplicate_problems_different_index_same_contest_id(mock_submission):
@@ -179,5 +186,6 @@ def test_deduplicate_problems_different_index_same_contest_id(mock_submission):
         is_solved=True,
     )
 
-    result = BaseMetricService._deduplicate_problems([submission1, submission2])
+    submission_collection = SubmissionCollection([submission1, submission2])
+    result = submission_collection.deduplicate_problems()
     assert result == [submission1, submission2]

backend/tests/unit/base_metric_service/test_filter_successful_submissions.py

@@ -1,4 +1,4 @@
-from backend.domain.services import BaseMetricService
+from backend.domain.services.base import SubmissionCollection
 
 
 def test_filter_successful_submissions_happy_path(mock_submission):
@@ -29,12 +29,14 @@ def test_filter_successful_submissions_happy_path(mock_submission):
         is_solved=True,
     )
 
-    result = BaseMetricService._filter_successful_submissions([submission1, submission2, submission3])
+    submission_collection = SubmissionCollection([submission1, submission2, submission3])
+    result = submission_collection.filter_successful_submissions()
 
     assert result == [submission2, submission3]
 
 def test_filter_successful_submissions_no_submissions(mock_submission):
-    result = BaseMetricService._filter_successful_submissions([])
+    submission_collection = SubmissionCollection([])
+    result = submission_collection.filter_successful_submissions()
     assert result == []
 
 def test_filter_successful_submissions_only_not_solved_submissions(mock_submission):
@@ -65,7 +67,8 @@ def test_filter_successful_submissions_only_not_solved_submissions(mock_submissi
         is_solved=False,
     )
 
-    result = BaseMetricService._filter_successful_submissions([submission1, submission2, submission3])
+    submission_collection = SubmissionCollection([submission1, submission2, submission3])
+    result = submission_collection.filter_successful_submissions()
 
     assert result == []
 
@@ -97,7 +100,8 @@ def test_filter_successful_submissions_only_solved_submissions(mock_submission):
         is_solved=True,
     )
 
-    result = BaseMetricService._filter_successful_submissions([submission1, submission2, submission3])
+    submission_collection = SubmissionCollection([submission1, submission2, submission3])
+    result = submission_collection.filter_successful_submissions()
 
     assert result == [submission1, submission2, submission3]
 
@@ -129,7 +133,8 @@ def test_filter_successful_submissions_one_solved_submission_to_the_problem(mock
         is_solved=False,
     )
 
-    result = BaseMetricService._filter_successful_submissions([submission1, submission2, submission3])
+    submission_collection = SubmissionCollection([submission1, submission2, submission3])
+    result = submission_collection.filter_successful_submissions()
 
     assert result == [submission2]
 

docs/ARCHITECTURE.md

@@ -111,7 +111,7 @@ HTTP Request → Route Handler → Check Redis Cache
 ### Key Backend Features
 
 **Submission Deduplication:**
-- `BaseMetricService._deduplicate_problems()` keeps only the first solve per problem
+- `SubmissionCollection.deduplicate_problems()` keeps only the first solve per problem
 - Problems identified by `(contest_id, index)` tuple
 - Critical for accurate statistics since users may solve problems multiple times