feat(billing): add billing_mode to providers (postpaid support) & UI/migration

src/dashboard/providers.rs

@@ -17,6 +17,7 @@ pub(super) struct UpdateProviderRequest {
     pub(super) api_key: Option<String>,
     pub(super) credit_balance: Option<f64>,
     pub(super) low_credit_threshold: Option<f64>,
+    pub(super) billing_mode: Option<String>,
 }
 
 pub(super) async fn handle_get_providers(State(state): State<DashboardState>) -> Json<ApiResponse<serde_json::Value>> {
@@ -24,11 +25,12 @@ pub(super) async fn handle_get_providers(State(state): State<DashboardState>) ->
     let config = &state.app_state.config;
     let pool = &state.app_state.db_pool;
 
-    // Load all overrides from database
-    let db_configs_result =
-        sqlx::query("SELECT id, enabled, base_url, credit_balance, low_credit_threshold FROM provider_configs")
-            .fetch_all(pool)
-            .await;
+    // Load all overrides from database (including billing_mode)
+    let db_configs_result = sqlx::query(
+        "SELECT id, enabled, base_url, credit_balance, low_credit_threshold, billing_mode FROM provider_configs",
+    )
+    .fetch_all(pool)
+    .await;
 
     let mut db_configs = HashMap::new();
     if let Ok(rows) = db_configs_result {
@@ -38,7 +40,8 @@ pub(super) async fn handle_get_providers(State(state): State<DashboardState>) ->
             let base_url: Option<String> = row.get("base_url");
             let balance: f64 = row.get("credit_balance");
             let threshold: f64 = row.get("low_credit_threshold");
-            db_configs.insert(id, (enabled, base_url, balance, threshold));
+            let billing_mode: Option<String> = row.get("billing_mode");
+            db_configs.insert(id, (enabled, base_url, balance, threshold, billing_mode));
         }
     }
 
@@ -80,15 +83,17 @@ pub(super) async fn handle_get_providers(State(state): State<DashboardState>) ->
 
         let mut balance = 0.0;
         let mut threshold = 5.0;
+        let mut billing_mode: Option<String> = None;
 
         // Apply database overrides
-        if let Some((db_enabled, db_url, db_balance, db_threshold)) = db_configs.get(id) {
+        if let Some((db_enabled, db_url, db_balance, db_threshold, db_billing)) = db_configs.get(id) {
             enabled = *db_enabled;
             if let Some(url) = db_url {
                 base_url = url.clone();
             }
             balance = *db_balance;
             threshold = *db_threshold;
+            billing_mode = db_billing.clone();
         }
 
         // Find models for this provider in registry
@@ -138,6 +143,7 @@ pub(super) async fn handle_get_providers(State(state): State<DashboardState>) ->
             "base_url": base_url,
             "credit_balance": balance,
             "low_credit_threshold": threshold,
+            "billing_mode": billing_mode,
             "last_used": None::<String>,
         }));
     }
@@ -185,10 +191,11 @@ pub(super) async fn handle_get_provider(
 
     let mut balance = 0.0;
     let mut threshold = 5.0;
+    let mut billing_mode: Option<String> = None;
 
     // Apply database overrides
     let db_config = sqlx::query(
-        "SELECT enabled, base_url, credit_balance, low_credit_threshold FROM provider_configs WHERE id = ?",
+        "SELECT enabled, base_url, credit_balance, low_credit_threshold, billing_mode FROM provider_configs WHERE id = ?",
     )
     .bind(&name)
     .fetch_optional(pool)
@@ -201,6 +208,7 @@ pub(super) async fn handle_get_provider(
         }
         balance = row.get::<f64, _>("credit_balance");
         threshold = row.get::<f64, _>("low_credit_threshold");
+        billing_mode = row.get::<Option<String>, _>("billing_mode");
     }
 
     // Find models for this provider
@@ -246,6 +254,7 @@ pub(super) async fn handle_get_provider(
         "base_url": base_url,
         "credit_balance": balance,
         "low_credit_threshold": threshold,
+        "billing_mode": billing_mode,
         "last_used": None::<String>,
     })))
 }
@@ -262,19 +271,20 @@ pub(super) async fn handle_update_provider(
 
     let pool = &state.app_state.db_pool;
 
-    // Update or insert into database
+    // Update or insert into database (include billing_mode)
     let result = sqlx::query(
         r#"
-        INSERT INTO provider_configs (id, display_name, enabled, base_url, api_key, credit_balance, low_credit_threshold)
-        VALUES (?, ?, ?, ?, ?, ?, ?)
+        INSERT INTO provider_configs (id, display_name, enabled, base_url, api_key, credit_balance, low_credit_threshold, billing_mode)
+        VALUES (?, ?, ?, ?, ?, ?, ?, ?)
         ON CONFLICT(id) DO UPDATE SET
             enabled = excluded.enabled,
             base_url = excluded.base_url,
             api_key = COALESCE(excluded.api_key, provider_configs.api_key),
             credit_balance = COALESCE(excluded.credit_balance, provider_configs.credit_balance),
             low_credit_threshold = COALESCE(excluded.low_credit_threshold, provider_configs.low_credit_threshold),
+            billing_mode = COALESCE(excluded.billing_mode, provider_configs.billing_mode),
             updated_at = CURRENT_TIMESTAMP
-        "#
+        "#,
     )
     .bind(&name)
     .bind(name.to_uppercase())
@@ -283,6 +293,7 @@ pub(super) async fn handle_update_provider(
     .bind(&payload.api_key)
     .bind(payload.credit_balance)
     .bind(payload.low_credit_threshold)
+    .bind(payload.billing_mode)
     .execute(pool)
     .await;
 

src/logging/mod.rs

@@ -100,13 +100,18 @@ impl RequestLogger {
         .execute(&mut *tx)
         .await?;
 
-        // Deduct from provider balance if successful (skip postpaid like Gemini)
-        if log.cost > 0.0 && log.provider != "gemini" {
-            sqlx::query("UPDATE provider_configs SET credit_balance = credit_balance - ? WHERE id = ?")
-                .bind(log.cost)
-                .bind(&log.provider)
-                .execute(&mut *tx)
-                .await?;
+        // Deduct from provider balance if successful.
+        // Providers configured with billing_mode = 'postpaid' will not have their
+        // credit_balance decremented. Use a conditional UPDATE so we don't need
+        // a prior SELECT and avoid extra round-trips.
+        if log.cost > 0.0 {
+            sqlx::query(
+                "UPDATE provider_configs SET credit_balance = credit_balance - ? WHERE id = ? AND (billing_mode IS NULL OR billing_mode != 'postpaid')",
+            )
+            .bind(log.cost)
+            .bind(&log.provider)
+            .execute(&mut *tx)
+            .await?;
         }
 
         tx.commit().await?;