Implement LLM Chat API with tool calling support (#21731)

* Implement initial tools definiton APIs

* Add initial chat completion API with tool support

* Implement other providers

* Cleanup

frigate/genai/llama_cpp.py

@@ -1,6 +1,7 @@
 """llama.cpp Provider for Frigate AI."""
 
 import base64
+import json
 import logging
 from typing import Any, Optional
 
@@ -99,3 +100,132 @@ class LlamaCppClient(GenAIClient):
     def get_context_size(self) -> int:
         """Get the context window size for llama.cpp."""
         return self.genai_config.provider_options.get("context_size", 4096)
+
+    def chat_with_tools(
+        self,
+        messages: list[dict[str, Any]],
+        tools: Optional[list[dict[str, Any]]] = None,
+        tool_choice: Optional[str] = "auto",
+    ) -> dict[str, Any]:
+        """
+        Send chat messages to llama.cpp server with optional tool definitions.
+
+        Uses the OpenAI-compatible endpoint but passes through all native llama.cpp
+        parameters (like slot_id, temperature, etc.) via provider_options.
+        """
+        if self.provider is None:
+            logger.warning(
+                "llama.cpp provider has not been initialized. Check your llama.cpp configuration."
+            )
+            return {
+                "content": None,
+                "tool_calls": None,
+                "finish_reason": "error",
+            }
+
+        try:
+            openai_tool_choice = None
+            if tool_choice:
+                if tool_choice == "none":
+                    openai_tool_choice = "none"
+                elif tool_choice == "auto":
+                    openai_tool_choice = "auto"
+                elif tool_choice == "required":
+                    openai_tool_choice = "required"
+
+            payload = {
+                "messages": messages,
+            }
+
+            if tools:
+                payload["tools"] = tools
+                if openai_tool_choice is not None:
+                    payload["tool_choice"] = openai_tool_choice
+
+            provider_opts = {
+                k: v for k, v in self.provider_options.items() if k != "context_size"
+            }
+            payload.update(provider_opts)
+
+            response = requests.post(
+                f"{self.provider}/v1/chat/completions",
+                json=payload,
+                timeout=self.timeout,
+            )
+            response.raise_for_status()
+            result = response.json()
+
+            if result is None or "choices" not in result or len(result["choices"]) == 0:
+                return {
+                    "content": None,
+                    "tool_calls": None,
+                    "finish_reason": "error",
+                }
+
+            choice = result["choices"][0]
+            message = choice.get("message", {})
+
+            content = message.get("content")
+            if content:
+                content = content.strip()
+            else:
+                content = None
+
+            tool_calls = None
+            if "tool_calls" in message and message["tool_calls"]:
+                tool_calls = []
+                for tool_call in message["tool_calls"]:
+                    try:
+                        function_data = tool_call.get("function", {})
+                        arguments_str = function_data.get("arguments", "{}")
+                        arguments = json.loads(arguments_str)
+                    except (json.JSONDecodeError, KeyError, TypeError) as e:
+                        logger.warning(
+                            f"Failed to parse tool call arguments: {e}, "
+                            f"tool: {function_data.get('name', 'unknown')}"
+                        )
+                        arguments = {}
+
+                    tool_calls.append(
+                        {
+                            "id": tool_call.get("id", ""),
+                            "name": function_data.get("name", ""),
+                            "arguments": arguments,
+                        }
+                    )
+
+            finish_reason = "error"
+            if "finish_reason" in choice and choice["finish_reason"]:
+                finish_reason = choice["finish_reason"]
+            elif tool_calls:
+                finish_reason = "tool_calls"
+            elif content:
+                finish_reason = "stop"
+
+            return {
+                "content": content,
+                "tool_calls": tool_calls,
+                "finish_reason": finish_reason,
+            }
+
+        except requests.exceptions.Timeout as e:
+            logger.warning("llama.cpp request timed out: %s", str(e))
+            return {
+                "content": None,
+                "tool_calls": None,
+                "finish_reason": "error",
+            }
+        except requests.exceptions.RequestException as e:
+            logger.warning("llama.cpp returned an error: %s", str(e))
+            return {
+                "content": None,
+                "tool_calls": None,
+                "finish_reason": "error",
+            }
+        except Exception as e:
+            logger.warning("Unexpected error in llama.cpp chat_with_tools: %s", str(e))
+            return {
+                "content": None,
+                "tool_calls": None,
+                "finish_reason": "error",
+            }