dave: reorganize ModelConfig

start to clean up the lib.rs a bit

Signed-off-by: William Casarin <jb55@jb55.com>

crates/notedeck_dave/src/config.rs

@@ -0,0 +1,45 @@
+use async_openai::config::OpenAIConfig;
+
+#[derive(Debug)]
+pub struct ModelConfig {
+    endpoint: Option<String>,
+    model: String,
+    api_key: Option<String>,
+}
+
+impl Default for ModelConfig {
+    fn default() -> Self {
+        ModelConfig {
+            endpoint: None,
+            model: "gpt-4o".to_string(),
+            api_key: std::env::var("OPENAI_API_KEY").ok(),
+        }
+    }
+}
+
+impl ModelConfig {
+    pub fn model(&self) -> &str {
+        &self.model
+    }
+
+    pub fn ollama() -> Self {
+        ModelConfig {
+            endpoint: std::env::var("OLLAMA_HOST").ok().map(|h| h + "/v1"),
+            model: "hhao/qwen2.5-coder-tools:latest".to_string(),
+            api_key: None,
+        }
+    }
+
+    pub fn to_api(&self) -> OpenAIConfig {
+        let mut cfg = OpenAIConfig::new();
+        if let Some(endpoint) = &self.endpoint {
+            cfg = cfg.with_api_base(endpoint.to_owned());
+        }
+
+        if let Some(api_key) = &self.api_key {
+            cfg = cfg.with_api_key(api_key.to_owned());
+        }
+
+        cfg
+    }
+}