from datetime import datetime
from app.extensions import db

MAINTENANCE_STATUSES = [
    ('open',        'Open / Diagnosed'),
    ('in_progress', 'In Progress'),
    ('closed',      'Closed'),
]


class MaintenanceRecord(db.Model):
    """A maintenance or service event performed on a single asset."""
    __tablename__ = 'maintenance_records'

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

    asset_id = db.Column(db.Integer, db.ForeignKey('assets.id'), nullable=False)

    start_date  = db.Column(db.Date, nullable=False)
    end_date    = db.Column(db.Date, nullable=True)

    status = db.Column(db.String(20), nullable=False, default='open')

    initial_diagnosis = db.Column(db.Text, nullable=True)
    action_taken      = db.Column(db.Text, nullable=True)
    action_result     = db.Column(db.Text, nullable=True)

    created_by_id = db.Column(db.Integer, db.ForeignKey('admin_users.id'), nullable=True)
    created_at    = db.Column(db.DateTime, default=datetime.utcnow)
    updated_at    = db.Column(db.DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    # Relationships
    asset      = db.relationship('Asset',      backref=db.backref('maintenance_records', lazy='dynamic'))
    created_by = db.relationship('AdminUser',  foreign_keys=[created_by_id])

    @property
    def is_open(self):
        return self.status != 'closed'

    def __repr__(self):
        return f'<MaintenanceRecord asset={self.asset_id} status={self.status}>'