Initial MCM project: FastAPI + Textual TUI unified messenger

MultiCustomerMessenger supporting Telegram (python-telegram-bot),
WhatsApp (Green API) and SMS (python-gsmmodem-new). REST API with
Bearer-token auth, SQLAlchemy models for MariaDB, APScheduler for
background polling, and Textual TUI running in same asyncio event-loop.

services/conversation_service.py

@@ -0,0 +1,85 @@
+from __future__ import annotations
+
+from datetime import datetime
+
+from sqlalchemy.orm import Session
+
+from db.models import Contact, Conversation, Message
+
+
+def get_all(db: Session, channel: str | None = None, archived: bool = False) -> list[Conversation]:
+    q = db.query(Conversation).filter(Conversation.is_archived == archived)
+    if channel:
+        q = q.filter(Conversation.channel == channel)
+    return q.order_by(Conversation.last_message_at.desc().nullslast()).all()
+
+
+def get_by_id(db: Session, conv_id: str) -> Conversation | None:
+    return db.query(Conversation).filter(Conversation.id == conv_id).first()
+
+
+def get_by_channel_id(db: Session, channel: str, channel_conversation_id: str) -> Conversation | None:
+    return (
+        db.query(Conversation)
+        .filter(
+            Conversation.channel == channel,
+            Conversation.channel_conversation_id == channel_conversation_id,
+        )
+        .first()
+    )
+
+
+def get_or_create(
+    db: Session,
+    channel: str,
+    channel_conversation_id: str,
+    contact: Contact,
+    title: str | None = None,
+) -> Conversation:
+    conv = get_by_channel_id(db, channel, channel_conversation_id)
+    if not conv:
+        conv = Conversation(
+            channel=channel,
+            channel_conversation_id=channel_conversation_id,
+            title=title or contact.name,
+        )
+        conv.participants.append(contact)
+        db.add(conv)
+        db.commit()
+        db.refresh(conv)
+    return conv
+
+
+def get_messages(
+    db: Session, conv_id: str, limit: int = 50, offset: int = 0
+) -> list[Message]:
+    return (
+        db.query(Message)
+        .filter(Message.conversation_id == conv_id)
+        .order_by(Message.created_at.asc())
+        .offset(offset)
+        .limit(limit)
+        .all()
+    )
+
+
+def unread_count(db: Session, conv_id: str) -> int:
+    return (
+        db.query(Message)
+        .filter(
+            Message.conversation_id == conv_id,
+            Message.direction == "inbound",
+            Message.read_at.is_(None),
+        )
+        .count()
+    )
+
+
+def mark_all_read(db: Session, conv_id: str) -> None:
+    now = datetime.utcnow()
+    db.query(Message).filter(
+        Message.conversation_id == conv_id,
+        Message.direction == "inbound",
+        Message.read_at.is_(None),
+    ).update({"read_at": now, "status": "read"})
+    db.commit()