feat: Implemented OAuth support for OpenAI models via Codex endpoints

src/client/openai_oauth.rs

@@ -0,0 +1,79 @@
+use super::oauth::{OAuthProvider, TokenRequestFormat};
+use base64::Engine;
+use base64::engine::general_purpose::URL_SAFE_NO_PAD;
+use serde_json::Value;
+
+pub struct OpenAIOAuthProvider;
+
+impl OAuthProvider for OpenAIOAuthProvider {
+    fn provider_name(&self) -> &str {
+        "openai"
+    }
+
+    fn client_id(&self) -> &str {
+        "app_EMoamEEZ73f0CkXaXp7hrann"
+    }
+
+    fn authorize_url(&self) -> &str {
+        "https://auth.openai.com/oauth/authorize"
+    }
+
+    fn token_url(&self) -> &str {
+        "https://auth.openai.com/oauth/token"
+    }
+
+    fn redirect_uri(&self) -> &str {
+        "http://localhost:1455/auth/callback"
+    }
+
+    fn scopes(&self) -> &str {
+        "openid profile email offline_access"
+    }
+
+    fn token_request_format(&self) -> TokenRequestFormat {
+        TokenRequestFormat::FormUrlEncoded
+    }
+
+    fn extra_authorize_params(&self) -> Vec<(&str, &str)> {
+        vec![
+            ("id_token_add_organizations", "true"),
+            ("codex_cli_simplified_flow", "true"),
+        ]
+    }
+
+    fn fixed_redirect_uri(&self) -> Option<String> {
+        Some("http://localhost:1455/auth/callback".to_string())
+    }
+
+    fn include_state_in_token_exchange(&self) -> bool {
+        false
+    }
+
+    fn extract_account_id(&self, response: &Value) -> Option<String> {
+        let id_token = response["id_token"].as_str().unwrap_or_default();
+        let access_token = response["access_token"].as_str().unwrap_or_default();
+        extract_account_id_from_jwt(id_token).or_else(|| extract_account_id_from_jwt(access_token))
+    }
+}
+
+fn extract_account_id_from_jwt(token: &str) -> Option<String> {
+    let parts: Vec<&str> = token.splitn(3, '.').collect();
+    if parts.len() < 2 {
+        return None;
+    }
+    let decoded = URL_SAFE_NO_PAD.decode(parts[1]).ok()?;
+    let claims: Value = serde_json::from_slice(&decoded).ok()?;
+    claims["chatgpt_account_id"]
+        .as_str()
+        .map(|s| s.to_string())
+        .or_else(|| {
+            claims["https://api.openai.com/auth"]["chatgpt_account_id"]
+                .as_str()
+                .map(|s| s.to_string())
+        })
+        .or_else(|| {
+            claims["organizations"][0]["id"]
+                .as_str()
+                .map(|s| s.to_string())
+        })
+}