feat(agent-chat): complete core workflow and strengthen auth rate limiting

backend/src/models/__init__.py

@@ -1,5 +1,15 @@
 from __future__ import annotations
 
+from models.agent_chat_message import AgentChatMessage
+from models.agent_chat_session import AgentChatSession
+from models.llm import Llm
+from models.llm_factory import LlmFactory
 from models.profile import Profile
 
-__all__ = ["Profile"]
+__all__ = [
+    "AgentChatMessage",
+    "AgentChatSession",
+    "Llm",
+    "LlmFactory",
+    "Profile",
+]

backend/src/models/agent_chat_message.py

@@ -0,0 +1,62 @@
+from __future__ import annotations
+
+from decimal import Decimal
+import uuid
+from enum import Enum
+
+from sqlalchemy import (
+    JSON,
+    Enum as SqlEnum,
+    ForeignKey,
+    Integer,
+    Numeric,
+    String,
+    Text,
+    UniqueConstraint,
+)
+from sqlalchemy.dialects.postgresql import JSONB, UUID
+from sqlalchemy.orm import Mapped, mapped_column
+
+from core.db.base import Base, SoftDeleteMixin, TimestampMixin
+
+
+class AgentChatMessageRole(str, Enum):
+    USER = "user"
+    ASSISTANT = "assistant"
+    SYSTEM = "system"
+    TOOL = "tool"
+
+
+class AgentChatMessage(TimestampMixin, SoftDeleteMixin, Base):
+    __tablename__: str = "messages"
+    __table_args__: tuple[UniqueConstraint] = (
+        UniqueConstraint("session_id", "seq", name="uq_messages_session_seq"),
+    )
+
+    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("sessions.id", ondelete="CASCADE"),
+        nullable=False,
+        index=True,
+    )
+    seq: Mapped[int] = mapped_column(Integer, nullable=False)
+    role: Mapped[AgentChatMessageRole] = mapped_column(
+        SqlEnum(
+            AgentChatMessageRole, name="agent_chat_message_role", native_enum=False
+        ),
+        nullable=False,
+    )
+    content: Mapped[str] = mapped_column(Text, nullable=False)
+    model_code: Mapped[str | None] = mapped_column(String(50), nullable=True)
+    tool_name: Mapped[str | None] = mapped_column(String(100), nullable=True)
+    input_tokens: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
+    output_tokens: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
+    cost: Mapped[Decimal] = mapped_column(Numeric(12, 6), nullable=False, default=0)
+    currency: Mapped[str] = mapped_column(String(3), nullable=False, default="USD")
+    latency_ms: Mapped[int | None] = mapped_column(Integer, nullable=True)
+    metadata_json: Mapped[dict[str, object] | None] = mapped_column(
+        "metadata", JSON().with_variant(JSONB, "postgresql"), nullable=True
+    )

backend/src/models/agent_chat_session.py

@@ -0,0 +1,64 @@
+from __future__ import annotations
+
+from datetime import datetime
+from decimal import Decimal
+import uuid
+from enum import Enum
+
+from sqlalchemy import (
+    DateTime,
+    Enum as SqlEnum,
+    ForeignKey,
+    Integer,
+    Numeric,
+    String,
+    func,
+    text,
+)
+from sqlalchemy.dialects.postgresql import UUID
+from sqlalchemy.orm import Mapped, mapped_column
+
+from core.db.base import Base, SoftDeleteMixin, TimestampMixin
+
+
+class AgentChatSessionStatus(str, Enum):
+    PENDING = "pending"
+    RUNNING = "running"
+    COMPLETED = "completed"
+    FAILED = "failed"
+
+
+class AgentChatSession(TimestampMixin, SoftDeleteMixin, Base):
+    __tablename__: str = "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("auth.users.id", ondelete="CASCADE"),
+        nullable=False,
+        index=True,
+    )
+    title: Mapped[str | None] = mapped_column(String(255), nullable=True)
+    status: Mapped[AgentChatSessionStatus] = mapped_column(
+        SqlEnum(
+            AgentChatSessionStatus, name="agent_chat_session_status", native_enum=False
+        ),
+        nullable=False,
+        default=AgentChatSessionStatus.PENDING,
+    )
+    last_activity_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
+        server_default=func.now(),
+        nullable=False,
+    )
+    message_count: Mapped[int] = mapped_column(
+        Integer, nullable=False, server_default=text("0")
+    )
+    total_tokens: Mapped[int] = mapped_column(
+        Integer, nullable=False, server_default=text("0")
+    )
+    total_cost: Mapped[Decimal] = mapped_column(
+        Numeric(12, 6), nullable=False, server_default=text("0")
+    )

backend/src/models/llm.py

@@ -0,0 +1,26 @@
+from __future__ import annotations
+
+import uuid
+
+from sqlalchemy import ForeignKey, String
+from sqlalchemy.dialects.postgresql import UUID
+from sqlalchemy.orm import Mapped, mapped_column
+
+from core.db.base import Base, SoftDeleteMixin, TimestampMixin
+
+
+class Llm(TimestampMixin, SoftDeleteMixin, Base):
+    __tablename__: str = "llms"
+
+    id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True), primary_key=True, default=uuid.uuid4
+    )
+    factory_id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True),
+        ForeignKey("llm_factory.id", ondelete="RESTRICT"),
+        nullable=False,
+        index=True,
+    )
+    model_code: Mapped[str] = mapped_column(
+        String(50), nullable=False, unique=True, index=True
+    )

backend/src/models/llm_factory.py

@@ -0,0 +1,22 @@
+from __future__ import annotations
+
+import uuid
+
+from sqlalchemy import String, Text
+from sqlalchemy.dialects.postgresql import UUID
+from sqlalchemy.orm import Mapped, mapped_column
+
+from core.db.base import Base, SoftDeleteMixin, TimestampMixin
+
+
+class LlmFactory(TimestampMixin, SoftDeleteMixin, Base):
+    __tablename__: str = "llm_factory"
+
+    id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True), primary_key=True, default=uuid.uuid4
+    )
+    name: Mapped[str] = mapped_column(
+        String(50), nullable=False, unique=True, index=True
+    )
+    request_url: Mapped[str] = mapped_column(String(255), nullable=False)
+    avatar: Mapped[str | None] = mapped_column(Text, nullable=True)