"""Machine relationship models."""

from shopdb.extensions import db
from .base import BaseModel


class RelationshipType(BaseModel):
    """Types of relationships between machines."""
    __tablename__ = 'relationshiptypes'

    relationshiptypeid = db.Column(db.Integer, primary_key=True)
    relationshiptype = db.Column(db.String(50), unique=True, nullable=False)
    description = db.Column(db.Text)

    # Example types:
    # - "Controls" (PC controls Equipment)
    # - "Dualpath" (Redundant path partner)
    # - "Backup" (Backup machine)

    def __repr__(self):
        return f"<RelationshipType {self.relationshiptype}>"


class MachineRelationship(BaseModel):
    """
    Relationships between machines.

    Examples:
    - PC controls CNC machine
    - Two CNCs are dualpath partners
    """
    __tablename__ = 'machinerelationships'

    relationshipid = db.Column(db.Integer, primary_key=True)

    parentmachineid = db.Column(
        db.Integer,
        db.ForeignKey('machines.machineid'),
        nullable=False
    )
    childmachineid = db.Column(
        db.Integer,
        db.ForeignKey('machines.machineid'),
        nullable=False
    )
    relationshiptypeid = db.Column(
        db.Integer,
        db.ForeignKey('relationshiptypes.relationshiptypeid'),
        nullable=False
    )

    notes = db.Column(db.Text)

    # Relationships
    parent_machine = db.relationship(
        'Machine',
        foreign_keys=[parentmachineid],
        backref='child_relationships'
    )
    child_machine = db.relationship(
        'Machine',
        foreign_keys=[childmachineid],
        backref='parent_relationships'
    )
    relationship_type = db.relationship('RelationshipType', backref='relationships')

    __table_args__ = (
        db.UniqueConstraint(
            'parentmachineid',
            'childmachineid',
            'relationshiptypeid',
            name='uq_machine_relationship'
        ),
    )

    def __repr__(self):
        return f"<MachineRelationship {self.parentmachineid} -> {self.childmachineid}>"