from __future__ import annotations

from datetime import datetime
from enum import Enum
from typing import Optional

from sqlalchemy import DateTime, Enum as SAEnum, ForeignKey, Index, JSON, String, UniqueConstraint, text
from sqlalchemy.dialects.mysql import BIGINT
from sqlalchemy.orm import Mapped, mapped_column, relationship

from backend.db.base import Base


class InstanceStatus(str, Enum):
    PENDING = "PENDING"
    RUNNING = "RUNNING"
    STOPPING = "STOPPING"
    STOPPED = "STOPPED"
    SHUTTING_DOWN = "SHUTTING_DOWN"
    TERMINATED = "TERMINATED"
    UNKNOWN = "UNKNOWN"


class InstanceDesiredStatus(str, Enum):
    RUNNING = "RUNNING"
    STOPPED = "STOPPED"
    TERMINATED = "TERMINATED"


class Instance(Base):
    __tablename__ = "instances"
    __table_args__ = (
        UniqueConstraint("account_id", "region", "instance_id", name="uniq_instance_cloud"),
        Index("idx_instances_customer", "customer_id"),
        Index("idx_instances_status", "status"),
        Index("idx_instances_region", "region"),
        Index("idx_instances_last_sync", "last_sync"),
    )

    id: Mapped[int] = mapped_column(BIGINT(unsigned=True), primary_key=True, autoincrement=True)
    customer_id: Mapped[int] = mapped_column(
        ForeignKey("customers.id", ondelete="CASCADE", onupdate="CASCADE"), nullable=False
    )
    credential_id: Mapped[Optional[int]] = mapped_column(
        ForeignKey("aws_credentials.id", ondelete="SET NULL", onupdate="CASCADE")
    )
    account_id: Mapped[str] = mapped_column(String(32), nullable=False)
    region: Mapped[str] = mapped_column(String(32), nullable=False)
    az: Mapped[Optional[str]] = mapped_column(String(32))
    instance_id: Mapped[str] = mapped_column(String(32), nullable=False)
    name_tag: Mapped[Optional[str]] = mapped_column(String(255))
    instance_type: Mapped[str] = mapped_column(String(64), nullable=False)
    ami_id: Mapped[Optional[str]] = mapped_column(String(64))
    os_name: Mapped[Optional[str]] = mapped_column(String(128))
    key_name: Mapped[Optional[str]] = mapped_column(String(128))
    public_ip: Mapped[Optional[str]] = mapped_column(String(45))
    private_ip: Mapped[Optional[str]] = mapped_column(String(45))
    status: Mapped[InstanceStatus] = mapped_column(
        SAEnum(InstanceStatus), nullable=False, server_default=text("'UNKNOWN'")
    )
    desired_status: Mapped[Optional[InstanceDesiredStatus]] = mapped_column(SAEnum(InstanceDesiredStatus))
    security_groups: Mapped[Optional[dict]] = mapped_column(JSON)
    subnet_id: Mapped[Optional[str]] = mapped_column(String(64))
    vpc_id: Mapped[Optional[str]] = mapped_column(String(64))
    launched_at: Mapped[Optional[datetime]] = mapped_column(DateTime)
    terminated_at: Mapped[Optional[datetime]] = mapped_column(DateTime)
    last_sync: Mapped[Optional[datetime]] = mapped_column(DateTime)
    last_cloud_state: Mapped[Optional[dict]] = mapped_column(JSON)
    created_at: Mapped[datetime] = mapped_column(DateTime, server_default=text("CURRENT_TIMESTAMP"), nullable=False)
    updated_at: Mapped[datetime] = mapped_column(
        DateTime, server_default=text("CURRENT_TIMESTAMP"), onupdate=text("CURRENT_TIMESTAMP"), nullable=False
    )

    customer: Mapped["Customer"] = relationship("Customer")
    credential: Mapped[Optional["AWSCredential"]] = relationship("AWSCredential", back_populates="instances")
    job_items: Mapped[list["JobItem"]] = relationship("JobItem", back_populates="instance")

    @property
    def credential_name(self) -> Optional[str]:
        if getattr(self, "credential", None):
            return self.credential.name
        return None

    @property
    def credential_label(self) -> Optional[str]:
        if getattr(self, "credential", None):
            return f"{self.credential.name} ({self.credential.account_id})"
        return None

    @property
    def owner_name(self) -> Optional[str]:
        if getattr(self, "customer", None):
            return self.customer.name or self.customer.contact_email
        return None

    @property
    def customer_name(self) -> Optional[str]:
        return self.owner_name