feat(phase-30): add coverage snapshots, temporal comparison and auto re-testing (T-230 to T-232)

backend/app/models/coverage_snapshot.py

@@ -0,0 +1,78 @@
+"""Coverage snapshot models — periodic snapshots of coverage state.
+
+CoverageSnapshot stores aggregate metrics at a point in time.
+SnapshotTechniqueState stores per-technique state (normalized, one row
+per technique per snapshot) to avoid bloated JSONB fields.
+"""
+
+import uuid
+from datetime import datetime
+
+from sqlalchemy import (
+    Column, String, Float, Integer, DateTime,
+    ForeignKey, Index,
+)
+from sqlalchemy.dialects.postgresql import UUID
+from sqlalchemy.orm import relationship
+
+from app.database import Base
+
+
+class CoverageSnapshot(Base):
+    """A point-in-time snapshot of the organisation's overall coverage."""
+
+    __tablename__ = "coverage_snapshots"
+
+    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
+    name = Column(String, nullable=True)  # e.g. "Pre-remediación Q1"
+    organization_score = Column(Float, nullable=False)
+    total_techniques = Column(Integer, nullable=False)
+    validated_count = Column(Integer, nullable=False)
+    partial_count = Column(Integer, nullable=False)
+    not_covered_count = Column(Integer, nullable=False)
+    in_progress_count = Column(Integer, nullable=False)
+    not_evaluated_count = Column(Integer, nullable=False)
+    created_by = Column(
+        UUID(as_uuid=True),
+        ForeignKey("users.id", ondelete="SET NULL"),
+        nullable=True,
+    )
+    created_at = Column(DateTime, default=datetime.utcnow)
+
+    # Relationships
+    creator = relationship("User", foreign_keys=[created_by])
+    technique_states = relationship(
+        "SnapshotTechniqueState",
+        back_populates="snapshot",
+        cascade="all, delete-orphan",
+    )
+
+
+class SnapshotTechniqueState(Base):
+    """Per-technique state within a snapshot (normalised storage)."""
+
+    __tablename__ = "snapshot_technique_states"
+
+    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
+    snapshot_id = Column(
+        UUID(as_uuid=True),
+        ForeignKey("coverage_snapshots.id", ondelete="CASCADE"),
+        nullable=False,
+    )
+    technique_id = Column(
+        UUID(as_uuid=True),
+        ForeignKey("techniques.id", ondelete="CASCADE"),
+        nullable=False,
+    )
+    mitre_id = Column(String, nullable=False)  # denormalised for fast queries
+    status = Column(String, nullable=False)
+    score = Column(Float, nullable=True)
+
+    # Relationships
+    snapshot = relationship("CoverageSnapshot", back_populates="technique_states")
+    technique = relationship("Technique")
+
+    __table_args__ = (
+        Index("ix_snapshot_technique_states_snapshot", "snapshot_id"),
+        Index("ix_snapshot_technique_states_technique", "technique_id"),
+    )