whatsapp integration

backend/app/whatsapp_graph_client.py

@@ -0,0 +1,56 @@
+import httpx
+
+from .config import settings
+
+
+class WhatsAppGraphError(Exception):
+    def __init__(self, detail: str, status_code: int = 502) -> None:
+        super().__init__(detail)
+        self.detail = detail
+        self.status_code = status_code
+
+
+class WhatsAppGraphClient:
+    def __init__(
+        self,
+        *,
+        access_token: str | None = None,
+        phone_number_id: str | None = None,
+        api_version: str | None = None,
+    ) -> None:
+        self.access_token = access_token or settings.whatsapp_access_token
+        self.phone_number_id = phone_number_id or settings.whatsapp_phone_number_id
+        self.api_version = api_version or settings.whatsapp_api_version
+
+    @property
+    def configured(self) -> bool:
+        return bool(self.access_token and self.phone_number_id)
+
+    def _messages_url(self) -> str:
+        return (
+            f"https://graph.facebook.com/{self.api_version}/"
+            f"{self.phone_number_id}/messages"
+        )
+
+    async def send_text(self, to: str, body: str) -> dict:
+        if not self.configured:
+            raise WhatsAppGraphError("WhatsApp Graph API is not configured", status_code=503)
+
+        payload = {
+            "messaging_product": "whatsapp",
+            "recipient_type": "individual",
+            "to": to,
+            "type": "text",
+            "text": {"preview_url": False, "body": body},
+        }
+        headers = {"Authorization": f"Bearer {self.access_token}"}
+        async with httpx.AsyncClient(timeout=30.0) as client:
+            response = await client.post(self._messages_url(), json=payload, headers=headers)
+        try:
+            data = response.json()
+        except ValueError:
+            data = {"raw": response.text}
+        if response.status_code >= 400:
+            detail = data.get("error", {}).get("message") if isinstance(data, dict) else response.text
+            raise WhatsAppGraphError(detail or "WhatsApp Graph API request failed", status_code=response.status_code)
+        return data