from sqlalchemy import Column, Integer, String, Float, DateTime, Date, ForeignKey, Boolean, Text
from sqlalchemy.sql import func
from .database import Base

class User(Base):
    __tablename__ = "users"

    id = Column(Integer, primary_key=True, index=True)
    username = Column(String, unique=True, index=True, nullable=False)
    hashed_password = Column(String, nullable=False)
    role = Column(String, default="user", nullable=False)  # admin, user, readonly
    created_at = Column(DateTime(timezone=True), server_default=func.now())


class Drug(Base):
    __tablename__ = "drugs"

    id = Column(Integer, primary_key=True, index=True)
    name = Column(String, unique=True, index=True, nullable=False)
    description = Column(String, nullable=True)
    is_controlled = Column(Boolean, nullable=False, default=False)
    created_at = Column(DateTime(timezone=True), server_default=func.now())
    updated_at = Column(DateTime(timezone=True), onupdate=func.now(), server_default=func.now())


class DrugVariant(Base):
    __tablename__ = "drug_variants"

    id = Column(Integer, primary_key=True, index=True)
    drug_id = Column(Integer, ForeignKey("drugs.id"), nullable=False)
    strength = Column(String, nullable=False)  # e.g., "5.4mg", "16mg", "100ml"
    quantity = Column(Float, nullable=False, default=0)
    unit = Column(String, nullable=False, default="units")  # tablets, bottles, ml, etc
    low_stock_threshold = Column(Float, nullable=False, default=10)
    created_at = Column(DateTime(timezone=True), server_default=func.now())
    updated_at = Column(DateTime(timezone=True), onupdate=func.now(), server_default=func.now())


class Dispensing(Base):
    __tablename__ = "dispensings"

    id = Column(Integer, primary_key=True, index=True)
    drug_variant_id = Column(Integer, ForeignKey("drug_variants.id"), nullable=False)
    batch_id = Column(Integer, ForeignKey("batches.id"), nullable=True)
    actor_user_id = Column(Integer, ForeignKey("users.id"), nullable=True)
    quantity = Column(Float, nullable=False)
    animal_name = Column(String, nullable=True)  # Name/ID of the animal (optional)
    user_name = Column(String, nullable=False)  # User who dispensed
    dispensed_at = Column(DateTime(timezone=True), server_default=func.now(), index=True)
    notes = Column(String, nullable=True)


class Location(Base):
    __tablename__ = "locations"

    id = Column(Integer, primary_key=True, index=True)
    name = Column(String, unique=True, index=True, nullable=False)
    is_active = Column(Boolean, nullable=False, default=True)
    created_at = Column(DateTime(timezone=True), server_default=func.now())
    updated_at = Column(DateTime(timezone=True), onupdate=func.now(), server_default=func.now())


class Batch(Base):
    __tablename__ = "batches"

    id = Column(Integer, primary_key=True, index=True)
    drug_variant_id = Column(Integer, ForeignKey("drug_variants.id"), nullable=False, index=True)
    batch_number = Column(String, nullable=False, index=True)
    quantity = Column(Float, nullable=False, default=0)
    expiry_date = Column(Date, nullable=False, index=True)
    location_id = Column(Integer, ForeignKey("locations.id"), nullable=False, index=True)
    received_at = Column(DateTime(timezone=True), nullable=False, server_default=func.now(), index=True)
    notes = Column(String, nullable=True)
    created_at = Column(DateTime(timezone=True), server_default=func.now())
    updated_at = Column(DateTime(timezone=True), onupdate=func.now(), server_default=func.now())


class DispensingAllocation(Base):
    __tablename__ = "dispensing_allocations"

    id = Column(Integer, primary_key=True, index=True)
    dispensing_id = Column(Integer, ForeignKey("dispensings.id"), nullable=False, index=True)
    batch_id = Column(Integer, ForeignKey("batches.id"), nullable=False, index=True)
    quantity = Column(Float, nullable=False)


class AuditLog(Base):
    __tablename__ = "audit_logs"

    id = Column(Integer, primary_key=True, index=True)
    action = Column(String, nullable=False, index=True)
    entity_type = Column(String, nullable=False, index=True)
    entity_id = Column(Integer, nullable=True, index=True)
    actor_user_id = Column(Integer, ForeignKey("users.id"), nullable=True, index=True)
    actor_username = Column(String, nullable=False, index=True)
    details = Column(Text, nullable=True)
    created_at = Column(DateTime(timezone=True), server_default=func.now(), index=True)