from datetime import datetime
from typing import Optional

from sqlalchemy import CheckConstraint, DateTime, ForeignKey, Integer, String, func
from sqlalchemy.orm import Mapped, mapped_column, relationship

from .base import Base


class SSHKey(Base):
    """Registry of SSH private key files stored on the server filesystem."""

    __tablename__ = "ssh_keys"

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    name: Mapped[str] = mapped_column(String(100), nullable=False, unique=True)
    path: Mapped[str] = mapped_column(String(500), nullable=False)
    description: Mapped[Optional[str]] = mapped_column(String(1000), nullable=True)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), nullable=False
    )


class ObjectSSHCredential(Base):
    """Ordered list of SSH credentials (password or key) for an object.

    Tried in ascending priority order when connecting to hosts of this object.
    type='password': username + password_enc required.
    type='key':      username + ssh_key_id required.
    """

    __tablename__ = "object_ssh_credentials"
    __table_args__ = (
        CheckConstraint("type IN ('password', 'key')", name="ck_obj_ssh_cred_type"),
    )

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    object_id: Mapped[int] = mapped_column(
        Integer, ForeignKey("objects.id", ondelete="CASCADE"), nullable=False, index=True
    )
    type: Mapped[str] = mapped_column(String(10), nullable=False)
    username: Mapped[str] = mapped_column(String(100), nullable=False)
    password_enc: Mapped[Optional[str]] = mapped_column(String(500), nullable=True)
    ssh_key_id: Mapped[Optional[int]] = mapped_column(
        Integer, ForeignKey("ssh_keys.id", ondelete="SET NULL"), nullable=True
    )
    priority: Mapped[int] = mapped_column(Integer, nullable=False, default=0)

    object: Mapped["Object"] = relationship("Object", back_populates="ssh_credentials")
    ssh_key: Mapped[Optional["SSHKey"]] = relationship("SSHKey")


class ObjectCategoryCredential(Base):
    """Per-category credentials on an object.

    protocol='ssh': SSH access to devices of this category.
    protocol='http': HTTP/API access (cameras, MikroTik, Proxmox, etc.).
    type='password': username + password_enc required.
    type='key':      username + ssh_key_id required (ssh only).
    """

    __tablename__ = "object_category_credentials"
    __table_args__ = (
        CheckConstraint("protocol IN ('ssh', 'http')", name="ck_obj_cat_cred_protocol"),
        CheckConstraint("type IN ('password', 'key')", name="ck_obj_cat_cred_type"),
    )

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    object_id: Mapped[int] = mapped_column(
        Integer, ForeignKey("objects.id", ondelete="CASCADE"), nullable=False, index=True
    )
    category: Mapped[str] = mapped_column(String(20), nullable=False)
    protocol: Mapped[str] = mapped_column(String(10), nullable=False)
    type: Mapped[str] = mapped_column(String(10), nullable=False, default="password")
    username: Mapped[str] = mapped_column(String(100), nullable=False)
    password_enc: Mapped[Optional[str]] = mapped_column(String(500), nullable=True)
    ssh_key_id: Mapped[Optional[int]] = mapped_column(
        Integer, ForeignKey("ssh_keys.id", ondelete="SET NULL"), nullable=True
    )
    priority: Mapped[int] = mapped_column(Integer, nullable=False, default=0)

    object: Mapped["Object"] = relationship("Object", back_populates="category_credentials")
    ssh_key: Mapped[Optional["SSHKey"]] = relationship("SSHKey")


class GlobalSSHCredential(Base):
    """App-wide SSH credential used as last-resort fallback for all objects/devices.

    Tried after all object-level credentials are exhausted.
    type='password': username + password_enc required.
    type='key':      username + ssh_key_id required.
    """

    __tablename__ = "global_ssh_credentials"
    __table_args__ = (
        CheckConstraint("type IN ('password', 'key')", name="ck_global_ssh_cred_type"),
    )

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    type: Mapped[str] = mapped_column(String(10), nullable=False)
    username: Mapped[str] = mapped_column(String(100), nullable=False)
    password_enc: Mapped[Optional[str]] = mapped_column(String(500), nullable=True)
    ssh_key_id: Mapped[Optional[int]] = mapped_column(
        Integer, ForeignKey("ssh_keys.id", ondelete="SET NULL"), nullable=True
    )
    priority: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
    description: Mapped[Optional[str]] = mapped_column(String(200), nullable=True)

    ssh_key: Mapped[Optional["SSHKey"]] = relationship("SSHKey")