Add shellgen core and backends modules

app/shellgen/backends/ollama.py

@@ -0,0 +1,94 @@
+"""Ollama backend implementation."""
+
+import ollama as ollama_client
+from typing import Optional
+
+from .base import LLMBackend
+
+
+class OllamaBackend(LLMBackend):
+    """Ollama API backend for local LLM inference."""
+
+    def __init__(
+        self,
+        host: str = "localhost:11434",
+        model: str = "codellama",
+        temperature: float = 0.1,
+        max_tokens: int = 500,
+    ):
+        """Initialize the Ollama backend.
+
+        Args:
+            host: Ollama server host.
+            model: Model name to use.
+            temperature: Generation temperature.
+            max_tokens: Maximum tokens to generate.
+        """
+        self.host = host
+        self._model = model
+        self.temperature = temperature
+        self.max_tokens = max_tokens
+        self._client = None
+
+    @property
+    def client(self):
+        """Get or create Ollama client."""
+        if self._client is None:
+            self._client = ollama_client.Client(host=self.host)
+        return self._client
+
+    def generate(self, prompt: str) -> str:
+        """Generate response using Ollama API.
+
+        Args:
+            prompt: The prompt to send.
+
+        Returns:
+            Generated response text.
+        """
+        try:
+            response = self.client.generate(
+                model=self._model,
+                prompt=prompt,
+                options={
+                    "temperature": self.temperature,
+                    "num_predict": self.max_tokens,
+                },
+            )
+
+            return response.get("response", "")
+
+        except Exception as e:
+            raise ConnectionError(f"Ollama API error: {e}")
+
+    def is_available(self) -> bool:
+        """Check if Ollama is running and model is available.
+
+        Returns:
+            True if backend is available.
+        """
+        try:
+            self.client.ps()
+            return True
+        except Exception:
+            return False
+
+    def get_model_name(self) -> str:
+        """Get the current model name.
+
+        Returns:
+            Model name string.
+        """
+        return self._model
+
+    def set_model(self, model: str) -> None:
+        """Set the model to use.
+
+        Args:
+            model: Name of the model.
+        """
+        self._model = model
+
+    def close(self) -> None:
+        """Clean up client resources."""
+        self._client = None