feat(T07): KI-Copilot with OpenRouter chat, voice input, action system, chat history

backend/app/models/copilot.py

@@ -0,0 +1,123 @@
+"""SQLAlchemy models for Copilot chat sessions and messages.
+
+Stores per-user chat history with action proposals from the AI assistant.
+"""
+
+import enum
+import uuid
+from datetime import datetime
+
+from sqlalchemy import DateTime, Enum, ForeignKey, String, Text, func
+from sqlalchemy.dialects.postgresql import JSONB, UUID
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from app.database import Base
+
+
+class CopilotRole(str, enum.Enum):
+    """Roles for chat messages."""
+    user = "user"
+    assistant = "assistant"
+
+
+class CopilotSession(Base):
+    """A chat session belonging to a user. Groups related messages."""
+
+    __tablename__ = "copilot_sessions"
+
+    id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True),
+        primary_key=True,
+        default=uuid.uuid4,
+    )
+    user_id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True),
+        ForeignKey("users.id", ondelete="CASCADE"),
+        nullable=False,
+        index=True,
+    )
+    title: Mapped[str] = mapped_column(
+        String(255), nullable=False, default="Neue Konversation",
+    )
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), nullable=False, server_default=func.now(),
+    )
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
+        nullable=False,
+        server_default=func.now(),
+        onupdate=func.now(),
+    )
+
+    messages: Mapped[list["CopilotChat"]] = relationship(
+        back_populates="session",
+        cascade="all, delete-orphan",
+        order_by="CopilotChat.created_at.asc()",
+        lazy="selectin",
+    )
+
+    def __repr__(self) -> str:
+        return f"<CopilotSession id={self.id} user_id={self.user_id} title={self.title}>"
+
+    def to_dict(self) -> dict:
+        """Serialize session for API responses."""
+        return {
+            "id": str(self.id),
+            "user_id": str(self.user_id),
+            "title": self.title,
+            "created_at": self.created_at.isoformat() if self.created_at else None,
+            "updated_at": self.updated_at.isoformat() if self.updated_at else None,
+            "messages": [m.to_dict() for m in (self.messages or [])],
+        }
+
+
+class CopilotChat(Base):
+    """A single chat message (user or assistant) within a session."""
+
+    __tablename__ = "copilot_chats"
+
+    id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True),
+        primary_key=True,
+        default=uuid.uuid4,
+    )
+    session_id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True),
+        ForeignKey("copilot_sessions.id", ondelete="CASCADE"),
+        nullable=False,
+        index=True,
+    )
+    user_id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True),
+        ForeignKey("users.id", ondelete="CASCADE"),
+        nullable=False,
+        index=True,
+    )
+    role: Mapped[CopilotRole] = mapped_column(
+        Enum(CopilotRole, name="copilot_role"),
+        nullable=False,
+    )
+    content: Mapped[str] = mapped_column(Text, nullable=False)
+    actions: Mapped[list | None] = mapped_column(
+        JSONB, nullable=True, default=None,
+    )
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), nullable=False, server_default=func.now(),
+    )
+
+    session: Mapped["CopilotSession"] = relationship(back_populates="messages")
+
+    def __repr__(self) -> str:
+        return f"<CopilotChat id={self.id} role={self.role} session_id={self.session_id}>"
+
+    def to_dict(self) -> dict:
+        """Serialize chat message for API responses."""
+        return {
+            "id": str(self.id),
+            "session_id": str(self.session_id),
+            "user_id": str(self.user_id),
+            "role": self.role.value if isinstance(self.role, CopilotRole) else self.role,
+            "content": self.content,
+            "actions": self.actions,
+            "created_at": self.created_at.isoformat() if self.created_at else None,
+        }