add: Calander and reservation mode implemented.

backend/models.py

@@ -402,3 +402,72 @@ class Alert(Base):
 
     created_at = Column(DateTime, default=datetime.utcnow)
     expires_at = Column(DateTime, nullable=True)  # Auto-dismiss after this time
+
+
+# ============================================================================
+# Fleet Calendar & Job Reservations
+# ============================================================================
+
+class JobReservation(Base):
+    """
+    Job reservations: reserve units for future jobs/projects.
+
+    Supports two assignment modes:
+    - "specific": Pick exact units (SN-001, SN-002, etc.)
+    - "quantity": Reserve a number of units (e.g., "need 8 seismographs")
+
+    Used by the Fleet Calendar to visualize unit availability over time.
+    """
+    __tablename__ = "job_reservations"
+
+    id = Column(String, primary_key=True, index=True)  # UUID
+    name = Column(String, nullable=False)  # "Job A - March deployment"
+    project_id = Column(String, nullable=True, index=True)  # Optional FK to Project
+
+    # Date range for the reservation
+    start_date = Column(Date, nullable=False)
+    end_date = Column(Date, nullable=True)  # Nullable = TBD / ongoing
+    estimated_end_date = Column(Date, nullable=True)  # For planning when end is TBD
+    end_date_tbd = Column(Boolean, default=False)  # True = end date unknown
+
+    # Assignment type: "specific" or "quantity"
+    assignment_type = Column(String, nullable=False, default="quantity")
+
+    # For quantity reservations
+    device_type = Column(String, default="seismograph")  # seismograph | slm
+    quantity_needed = Column(Integer, nullable=True)  # e.g., 8 units
+
+    # Metadata
+    notes = Column(Text, nullable=True)
+    color = Column(String, default="#3B82F6")  # For calendar display (blue default)
+
+    created_at = Column(DateTime, default=datetime.utcnow)
+    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
+
+
+class JobReservationUnit(Base):
+    """
+    Links specific units to job reservations.
+
+    Used when:
+    - assignment_type="specific": Units are directly assigned
+    - assignment_type="quantity": Units can be filled in later
+
+    Supports unit swaps: same reservation can have multiple units with
+    different date ranges (e.g., BE17353 Feb-Jun, then BE18438 Jun-Nov).
+    """
+    __tablename__ = "job_reservation_units"
+
+    id = Column(String, primary_key=True, index=True)  # UUID
+    reservation_id = Column(String, nullable=False, index=True)  # FK to JobReservation
+    unit_id = Column(String, nullable=False, index=True)  # FK to RosterUnit
+
+    # Unit-specific date range (for swaps) - defaults to reservation dates if null
+    unit_start_date = Column(Date, nullable=True)  # When this specific unit starts
+    unit_end_date = Column(Date, nullable=True)  # When this unit ends (swap out date)
+    unit_end_tbd = Column(Boolean, default=False)  # True = end unknown (until cal expires or job ends)
+
+    # Track how this assignment was made
+    assignment_source = Column(String, default="specific")  # "specific" | "filled" | "swap"
+    assigned_at = Column(DateTime, default=datetime.utcnow)
+    notes = Column(Text, nullable=True)  # "Replacing BE17353" etc.