from sqlalchemy import Column, Integer, String, Text, ForeignKey
from sqlalchemy.orm import declarative_base, relationship

Base = declarative_base()


class Device(Base):
    __tablename__ = "device"

    id = Column(Integer, primary_key=True, autoincrement=True)
    name = Column(String(100), nullable=False, unique=True)
    battery_slots = Column(Integer, nullable=False, default=1)
    device_type   = Column(String(50),  nullable=True)
    notes = Column(Text, nullable=True)

    batteries = relationship("Battery", back_populates="device")

    def installed_count(self):
        return sum(1 for b in self.batteries if b.status == "installed")

    def installed_brands(self):
        return set(b.brand for b in self.batteries if b.status == "installed")

    def has_mixed_brands(self):
        return len(self.installed_brands()) > 1

    def __repr__(self):
        return f"<Device {self.name}>"


class Battery(Base):
    __tablename__ = "battery"

    id = Column(Integer, primary_key=True, autoincrement=True)
    label = Column(String(50), nullable=False)
    brand = Column(String(100), nullable=False)
    status = Column(String(20), nullable=False, default="available")
    device_id = Column(Integer, ForeignKey("device.id", ondelete="SET NULL"), nullable=True)
    notes = Column(Text, nullable=True)

    # Optional metadata
    size                = Column(String(20),  nullable=True)   # AA, AAA, 18650, CR2032 …
    chemistry           = Column(String(20),  nullable=True)   # NiMH, Alkaline, Li-ion …
    capacity_mah        = Column(Integer,     nullable=True)   # nominal capacity in mAh
    tested_capacity_mah = Column(Integer,     nullable=True)   # last measured capacity in mAh
    tested_date         = Column(String(10),  nullable=True)   # YYYY-MM-DD of last test
    charge_cycles       = Column(Integer,     nullable=True)   # number of charge cycles
    purchase_date       = Column(String(10),  nullable=True)   # YYYY-MM-DD when purchased
    storage_location    = Column(String(100), nullable=True)   # where stored when not installed

    device = relationship("Device", back_populates="batteries")

    def is_available(self):
        return self.status == "available"

    def is_retired(self):
        return self.status == "retired"

    def is_installed(self):
        return self.status == "installed"

    def __repr__(self):
        return f"<Battery {self.label}>"