rename envoyfilter => arch (#91)

* rename envoyfilter => arch

* fix more files

* more fixes

* more renames

arch/src/llm_providers.rs

@@ -0,0 +1,47 @@
+#[non_exhaustive]
+pub struct LlmProviders;
+
+impl LlmProviders {
+    pub const OPENAI_PROVIDER: LlmProvider<'static> = LlmProvider {
+        name: "openai",
+        api_key_header: "x-arch-openai-api-key",
+        model: "gpt-3.5-turbo",
+    };
+    pub const MISTRAL_PROVIDER: LlmProvider<'static> = LlmProvider {
+        name: "mistral",
+        api_key_header: "x-arch-mistral-api-key",
+        model: "mistral-large-latest",
+    };
+
+    pub const VARIANTS: &'static [LlmProvider<'static>] =
+        &[Self::OPENAI_PROVIDER, Self::MISTRAL_PROVIDER];
+}
+
+pub struct LlmProvider<'prov> {
+    name: &'prov str,
+    api_key_header: &'prov str,
+    model: &'prov str,
+}
+
+impl AsRef<str> for LlmProvider<'_> {
+    fn as_ref(&self) -> &str {
+        self.name
+    }
+}
+
+impl std::fmt::Display for LlmProvider<'_> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.name)
+    }
+}
+
+impl LlmProvider<'_> {
+    pub fn api_key_header(&self) -> &str {
+        self.api_key_header
+    }
+
+    pub fn choose_model(&self) -> &str {
+        // In the future this can be a more complex function balancing reliability, cost, performance, etc.
+        self.model
+    }
+}