from datetime import datetime, timezone

from sqlalchemy import (
    Boolean, Column, DateTime, Float, ForeignKey, Integer, String, Table, Text,
)
from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.database import Base


def utcnow() -> datetime:
    return datetime.now(timezone.utc)


key_endpoint_access = Table(
    "key_endpoint_access",
    Base.metadata,
    Column("api_key_id", ForeignKey("api_keys.id", ondelete="CASCADE"), primary_key=True),
    Column("endpoint_id", ForeignKey("endpoints.id", ondelete="CASCADE"), primary_key=True),
)


class User(Base):
    __tablename__ = "users"

    id: Mapped[int] = mapped_column(primary_key=True)
    username: Mapped[str] = mapped_column(String(64), unique=True, index=True)
    password_hash: Mapped[str] = mapped_column(String(256))
    is_active: Mapped[bool] = mapped_column(Boolean, default=True)
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=utcnow)

    api_keys: Mapped[list["ApiKey"]] = relationship(
        back_populates="user", cascade="all, delete-orphan"
    )


class Service(Base):
    __tablename__ = "services"

    id: Mapped[int] = mapped_column(primary_key=True)
    name: Mapped[str] = mapped_column(String(128))
    slug: Mapped[str] = mapped_column(String(64), unique=True, index=True)
    base_url: Mapped[str] = mapped_column(String(512))
    description: Mapped[str] = mapped_column(Text, default="")
    timeout_seconds: Mapped[float] = mapped_column(Float, default=30.0)
    # Disable for upstreams with self-signed / internal-CA certificates.
    verify_tls: Mapped[bool] = mapped_column(Boolean, default=True)
    is_active: Mapped[bool] = mapped_column(Boolean, default=True)
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=utcnow)

    endpoints: Mapped[list["Endpoint"]] = relationship(
        back_populates="service", cascade="all, delete-orphan",
        order_by="Endpoint.path",
    )


class Endpoint(Base):
    """A callable route of an upstream service.

    `method` is an HTTP verb or '*' (any). `path` starts with '/' and may use
    '{param}' (one segment), '*' (any within a segment) and '**' (any depth),
    e.g. '/orders/{id}', '/reports/**'.
    """
    __tablename__ = "endpoints"

    id: Mapped[int] = mapped_column(primary_key=True)
    service_id: Mapped[int] = mapped_column(ForeignKey("services.id", ondelete="CASCADE"))
    method: Mapped[str] = mapped_column(String(10), default="*")
    path: Mapped[str] = mapped_column(String(512))
    description: Mapped[str] = mapped_column(Text, default="")

    service: Mapped[Service] = relationship(back_populates="endpoints")
    api_keys: Mapped[list["ApiKey"]] = relationship(
        secondary=key_endpoint_access, back_populates="endpoints"
    )

    @property
    def label(self) -> str:
        return f"{self.method} {self.path}"


class ApiKey(Base):
    __tablename__ = "api_keys"

    id: Mapped[int] = mapped_column(primary_key=True)
    user_id: Mapped[int] = mapped_column(ForeignKey("users.id", ondelete="CASCADE"))
    name: Mapped[str] = mapped_column(String(128))
    prefix: Mapped[str] = mapped_column(String(16), index=True)  # first chars, for display
    key_hash: Mapped[str] = mapped_column(String(128), unique=True, index=True)
    rate_limit_per_minute: Mapped[int] = mapped_column(Integer, default=60)  # 0 = unlimited
    is_active: Mapped[bool] = mapped_column(Boolean, default=True)
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=utcnow)
    last_used_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)

    user: Mapped[User] = relationship(back_populates="api_keys")
    endpoints: Mapped[list[Endpoint]] = relationship(
        secondary=key_endpoint_access, back_populates="api_keys"
    )


class RequestLog(Base):
    __tablename__ = "request_logs"

    id: Mapped[int] = mapped_column(primary_key=True)
    timestamp: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=utcnow, index=True)
    api_key_id: Mapped[int | None] = mapped_column(
        ForeignKey("api_keys.id", ondelete="SET NULL"), nullable=True, index=True
    )
    service_id: Mapped[int | None] = mapped_column(
        ForeignKey("services.id", ondelete="SET NULL"), nullable=True, index=True
    )
    endpoint_id: Mapped[int | None] = mapped_column(
        ForeignKey("endpoints.id", ondelete="SET NULL"), nullable=True, index=True
    )
    method: Mapped[str] = mapped_column(String(10))
    path: Mapped[str] = mapped_column(String(1024))
    query_string: Mapped[str] = mapped_column(String(2048), default="")
    status_code: Mapped[int] = mapped_column(Integer, index=True)
    latency_ms: Mapped[float] = mapped_column(Float)
    client_ip: Mapped[str] = mapped_column(String(64), default="")
    request_body: Mapped[str] = mapped_column(Text, default="")
    response_body: Mapped[str] = mapped_column(Text, default="")

    api_key: Mapped[ApiKey | None] = relationship()
    service: Mapped[Service | None] = relationship()
    endpoint: Mapped[Endpoint | None] = relationship()