Add the ability to use LLM Providers from the Arch config (#112)

Signed-off-by: José Ulises Niño Rivera <junr03@users.noreply.github.com>

arch/src/routing.rs

@@ -1,13 +1,42 @@
-use crate::llm_providers::{LlmProvider, LlmProviders};
-use rand::{seq::SliceRandom, thread_rng};
+use std::rc::Rc;
 
-pub fn get_llm_provider<'hostname>(deterministic: bool) -> &'static LlmProvider<'hostname> {
-    if deterministic {
-        &LlmProviders::OPENAI_PROVIDER
-    } else {
-        let mut rng = thread_rng();
-        LlmProviders::VARIANTS
-            .choose(&mut rng)
-            .expect("There should always be at least one llm provider")
+use crate::llm_providers::LlmProviders;
+use public_types::configuration::LlmProvider;
+use rand::{seq::IteratorRandom, thread_rng};
+
+pub enum ProviderHint {
+    Default,
+    Name(String),
+}
+
+impl From<String> for ProviderHint {
+    fn from(value: String) -> Self {
+        match value.as_str() {
+            "default" => ProviderHint::Default,
+            _ => ProviderHint::Name(value),
+        }
     }
 }
+
+pub fn get_llm_provider(
+    llm_providers: &LlmProviders,
+    provider_hint: Option<ProviderHint>,
+) -> Rc<LlmProvider> {
+    let maybe_provider = provider_hint.and_then(|hint| match hint {
+        ProviderHint::Default => llm_providers.default(),
+        // FIXME: should a non-existent name in the hint be more explicit? i.e, return a BAD_REQUEST?
+        ProviderHint::Name(name) => llm_providers.get(&name),
+    });
+
+    if let Some(provider) = maybe_provider {
+        return provider;
+    }
+
+    let mut rng = thread_rng();
+    llm_providers
+        .iter()
+        .choose(&mut rng)
+        .expect("There should always be at least one llm provider")
+        .1
+        .clone()
+}