split wasm filter (#186)

* split wasm filter

* fix int and unit tests

* rename public_types => common and move common code there

* rename

* fix int test

crates/common/src/routing.rs

@@ -0,0 +1,50 @@
+use std::rc::Rc;
+
+use crate::{configuration, llm_providers::LlmProviders};
+use configuration::LlmProvider;
+use log::debug;
+use rand::{seq::IteratorRandom, thread_rng};
+
+#[derive(Debug)]
+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;
+    }
+
+    if llm_providers.default().is_some() {
+        debug!("no llm provider found for hint, using default llm provider");
+        return llm_providers.default().unwrap();
+    }
+
+    debug!("no default llm found, using random llm provider");
+    let mut rng = thread_rng();
+    llm_providers
+        .iter()
+        .choose(&mut rng)
+        .expect("There should always be at least one llm provider")
+        .1
+        .clone()
+}