feat(subscription): Add endpoint to get Subscription estimate (#9637)

Co-authored-by: hyperswitch-bot[bot] <148525504+hyperswitch-bot[bot]@users.noreply.github.com>
Co-authored-by: Gaurav Rawat <104276743+GauravRawat369@users.noreply.github.com>

crates/api_models/src/lib.rs

@@ -44,7 +44,6 @@ pub mod relay;
 #[cfg(feature = "v2")]
 pub mod revenue_recovery_data_backfill;
 pub mod routing;
-#[cfg(feature = "v1")]
 pub mod subscription;
 pub mod surcharge_decision_configs;
 pub mod three_ds_decision_rule;

crates/api_models/src/subscription.rs

@@ -446,3 +446,52 @@ pub struct Invoice {
 }
 
 impl ApiEventMetric for ConfirmSubscriptionResponse {}
+
+#[derive(Debug, Clone, serde::Serialize, serde::Deserialize, ToSchema)]
+pub struct EstimateSubscriptionQuery {
+    /// Identifier for the associated subscription plan.
+    pub plan_id: Option<String>,
+
+    /// Identifier for the associated item_price_id for the subscription.
+    pub item_price_id: String,
+
+    /// Idenctifier for the coupon code for the subscription.
+    pub coupon_code: Option<String>,
+}
+
+impl ApiEventMetric for EstimateSubscriptionQuery {}
+
+#[derive(Debug, Clone, serde::Serialize, ToSchema)]
+pub struct EstimateSubscriptionResponse {
+    /// Estimated amount to be charged for the invoice.
+    pub amount: MinorUnit,
+    /// Currency for the amount.
+    pub currency: api_enums::Currency,
+    /// Identifier for the associated plan_id.
+    pub plan_id: Option<String>,
+    /// Identifier for the associated item_price_id for the subscription.
+    pub item_price_id: Option<String>,
+    /// Idenctifier for the coupon code for the subscription.
+    pub coupon_code: Option<String>,
+    /// Identifier for customer.
+    pub customer_id: Option<common_utils::id_type::CustomerId>,
+    pub line_items: Vec<SubscriptionLineItem>,
+}
+
+#[derive(Debug, Clone, serde::Serialize, ToSchema)]
+pub struct SubscriptionLineItem {
+    /// Unique identifier for the line item.
+    pub item_id: String,
+    /// Type of the line item.
+    pub item_type: String,
+    /// Description of the line item.
+    pub description: String,
+    /// Amount for the line item.
+    pub amount: MinorUnit,
+    /// Currency for the line item
+    pub currency: common_enums::Currency,
+    /// Quantity of the line item.
+    pub quantity: i64,
+}
+
+impl ApiEventMetric for EstimateSubscriptionResponse {}