Fix SSE route dependency and align architecture docs

backend/app/domain/conversation/__init__.py

@@ -0,0 +1,15 @@
+"""Initialize the app.domain.conversation package."""
+
+from .models import AnswerResult, AnswerSource, ConversationMessage, ConversationSession
+from .ports import AnswerGenerator, ConversationStore
+# Keep package boundaries explicit so backend imports stay predictable.
+
+
+__all__ = [
+    "AnswerGenerator",
+    "AnswerResult",
+    "AnswerSource",
+    "ConversationMessage",
+    "ConversationSession",
+    "ConversationStore",
+]

backend/app/domain/conversation/models.py

@@ -0,0 +1,53 @@
+"""Define domain models for conversation."""
+
+from __future__ import annotations
+
+from dataclasses import dataclass, field
+from typing import Any
+# Keep module behavior explicit so the backend flow stays easy to audit.
+
+
+
+@dataclass
+class AnswerSource:
+    """Represent answer source data."""
+    doc_id: str
+    doc_name: str
+    chunk_id: str
+    section_title: str
+    page_number: int
+    score: float
+    content: str
+    metadata: dict[str, Any] = field(default_factory=dict)
+
+
+@dataclass
+class ConversationMessage:
+    """Represent conversation message data."""
+    role: str
+    content: str
+    timestamp: int
+    sources: list[dict[str, Any]] = field(default_factory=list)
+
+
+@dataclass
+class ConversationSession:
+    """Represent conversation session data."""
+    session_id: str
+    messages: list[ConversationMessage] = field(default_factory=list)
+    created_at: int = 0
+    updated_at: int = 0
+    metadata: dict[str, Any] = field(default_factory=dict)
+
+
+@dataclass
+class AnswerResult:
+    """Represent answer result data."""
+    answer: str
+    sources: list[AnswerSource] = field(default_factory=list)
+    model: str = ""
+    latency_ms: int = 0
+    retrieved_count: int = 0
+    context_tokens: int = 0
+    truncated: bool = False
+    error: str | None = None

backend/app/domain/conversation/ports.py

@@ -0,0 +1,78 @@
+"""Define domain ports for conversation."""
+
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+from typing import Generator
+
+from app.domain.retrieval.models import RetrievedChunk
+
+from .models import AnswerResult, ConversationSession
+# Keep domain contracts explicit so adapters can swap implementations cleanly.
+
+
+
+class AnswerGenerator(ABC):
+    """Represent the Answer Generator type."""
+    @abstractmethod
+    def generate(
+        self,
+        *,
+        query: str,
+        retrieved_chunks: list[RetrievedChunk],
+        history: list[dict[str, str]] | None = None,
+        provider: str | None = None,
+        model: str | None = None,
+        prompt_template: str | None = None,
+    ) -> AnswerResult:
+        """Handle generate for the Answer Generator instance."""
+        pass
+
+    @abstractmethod
+    def stream_generate(
+        self,
+        *,
+        query: str,
+        retrieved_chunks: list[RetrievedChunk],
+        history: list[dict[str, str]] | None = None,
+        provider: str | None = None,
+        model: str | None = None,
+        prompt_template: str | None = None,
+    ) -> Generator[dict, None, AnswerResult]:
+        """Stream generate for the Answer Generator instance."""
+        pass
+
+
+class ConversationStore(ABC):
+    """Provide the Conversation Store store implementation."""
+    @abstractmethod
+    def create_session(self, metadata: dict | None = None) -> ConversationSession:
+        """Create session for the Conversation Store instance."""
+        pass
+
+    @abstractmethod
+    def get_session(self, session_id: str) -> ConversationSession | None:
+        """Return session for the Conversation Store instance."""
+        pass
+
+    @abstractmethod
+    def save_message(
+        self,
+        session_id: str,
+        *,
+        role: str,
+        content: str,
+        sources: list[dict] | None = None,
+    ) -> ConversationSession | None:
+        """Save message for the Conversation Store instance."""
+        pass
+
+    @abstractmethod
+    def delete_session(self, session_id: str) -> bool:
+        """Delete session for the Conversation Store instance."""
+        pass
+
+    @abstractmethod
+    def list_sessions(self) -> list[dict]:
+        """List sessions for the Conversation Store instance."""
+        pass