from datetime import datetime
from app.extensions import db

ASSET_TYPES = [
    'Laptop', 'Desktop', 'Monitor', 'Keyboard', 'Mouse',
    'Headset', 'Docking Station', 'Printer', 'Scanner',
    'Tablet', 'Phone', 'Server', 'Network Equipment', 'Other',
]

ASSET_STATUSES = [
    ('available', 'Available'),
    ('assigned', 'Assigned'),
    ('maintenance', 'In Maintenance'),
    ('retired', 'Retired'),
    ('lost', 'Lost / Stolen'),
]


class Asset(db.Model):
    """Hardware asset tracked by serial number and/or service tag."""
    __tablename__ = 'assets'

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

    # Primary identifiers
    serial_number = db.Column(db.String(200), unique=True, nullable=False, index=True)
    service_tag = db.Column(db.String(200), unique=True, nullable=True, index=True)
    asset_tag = db.Column(db.String(100), nullable=True)  # internal barcode / tag

    # Classification
    asset_type = db.Column(db.String(50), nullable=False)
    brand = db.Column(db.String(100), nullable=True)
    model = db.Column(db.String(150), nullable=True)

    # Technical specs (optional)
    processor = db.Column(db.String(200), nullable=True)
    ram_gb = db.Column(db.Integer, nullable=True)
    storage_gb = db.Column(db.Integer, nullable=True)
    operating_system = db.Column(db.String(100), nullable=True)
    mac_address = db.Column(db.String(50), nullable=True)

    # Procurement
    purchase_date = db.Column(db.Date, nullable=True)
    warranty_expiry = db.Column(db.Date, nullable=True)
    purchase_price = db.Column(db.Numeric(10, 2), nullable=True)
    supplier = db.Column(db.String(200), nullable=True)
    po_number = db.Column(db.String(100), nullable=True)

    # Current state
    status = db.Column(db.String(30), default='available', nullable=False)
    location = db.Column(db.String(200), nullable=True)
    notes = db.Column(db.Text, nullable=True)

    # Compliance / IT checks — Desktop & Laptop only
    inventory_number   = db.Column(db.String(100), nullable=True)
    ad_device_name     = db.Column(db.String(150), nullable=True)
    location_note      = db.Column(db.Text, nullable=True)          # free-text location note

    # Current boolean state
    encryption_checked = db.Column(db.Boolean, default=False, nullable=False)
    backup_checked     = db.Column(db.Boolean, default=False, nullable=False)
    hr_notified        = db.Column(db.Boolean, default=False, nullable=False)

    # Who last changed each check and when
    encryption_checked_by_id = db.Column(db.Integer, db.ForeignKey('admin_users.id'), nullable=True)
    encryption_checked_at    = db.Column(db.DateTime, nullable=True)
    backup_checked_by_id     = db.Column(db.Integer, db.ForeignKey('admin_users.id'), nullable=True)
    backup_checked_at        = db.Column(db.DateTime, nullable=True)
    hr_notified_by_id        = db.Column(db.Integer, db.ForeignKey('admin_users.id'), nullable=True)
    hr_notified_at           = db.Column(db.DateTime, nullable=True)

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

    # Relationships
    assignments = db.relationship(
        'Assignment', backref='asset', lazy='dynamic', cascade='all, delete-orphan'
    )
    paperwork_docs = db.relationship(
        'Paperwork', backref='asset', lazy='dynamic'
    )
    compliance_checks = db.relationship(
        'ComplianceCheck', back_populates='asset', lazy='dynamic',
        cascade='all, delete-orphan',
        order_by='ComplianceCheck.performed_at.desc()',
    )
    created_by              = db.relationship('AdminUser', foreign_keys=[created_by_id])
    encryption_checked_by   = db.relationship('AdminUser', foreign_keys=[encryption_checked_by_id])
    backup_checked_by       = db.relationship('AdminUser', foreign_keys=[backup_checked_by_id])
    hr_notified_by          = db.relationship('AdminUser', foreign_keys=[hr_notified_by_id])

    @property
    def current_assignment(self):
        return self.assignments.filter_by(is_active=True).first()

    @property
    def current_user(self):
        a = self.current_assignment
        return a.user if a else None

    @property
    def status_badge(self):
        colours = {
            'available': 'success',
            'assigned': 'primary',
            'maintenance': 'warning',
            'retired': 'secondary',
            'lost': 'danger',
        }
        return colours.get(self.status, 'secondary')

    def __repr__(self):
        return f'<Asset sn={self.serial_number} type={self.asset_type}>'