Automatic USDC Reward Distribution on Course Completion

contracts/course-registry/Cargo.toml

@@ -13,6 +13,7 @@ doctest = false
 
 [dependencies]
 soroban-sdk = { workspace = true }
+reward-pool = { path = "../reward-pool" }
 
 [dev-dependencies]
 soroban-sdk = { workspace = true, features = ["testutils"] }

contracts/course-registry/src/lib.rs

@@ -3,6 +3,7 @@ use soroban_sdk::{contract, contractevent, contractimpl, Address, BytesN, Env};
 
 pub mod types;
 use types::{Course, DataKey};
+use reward_pool::RewardPoolClient;
 
 #[contract]
 pub struct CourseRegistry;
@@ -188,6 +189,22 @@ impl CourseRegistry {
         CourseStatusChanged { id, active }.publish(&env);
     }
 
+    /// Sets the RewardPool contract address. Only callable by the Protocol Admin.
+    pub fn set_reward_pool(env: Env, admin: Address, reward_pool: Address) {
+        admin.require_auth();
+
+        let stored_admin: Address = env
+            .storage()
+            .instance()
+            .get(&DataKey::Admin)
+            .expect("Contract not initialized");
+        assert!(admin == stored_admin, "Unauthorized: Caller is not the protocol admin");
+
+        env.storage()
+            .instance()
+            .set(&DataKey::RewardPool, &reward_pool);
+    }
+
     /// Returns true if the learner has completed all modules in the course.
     pub fn is_course_finished(env: Env, learner: Address, id: u32) -> bool {
         let course: Course = env
@@ -281,11 +298,27 @@ impl CourseRegistry {
 
         // 8. Emit ModuleCompleted event
         ModuleCompleted {
-            learner,
+            learner: learner.clone(),
             course_id: id,
             new_progress,
         }
         .publish(&env);
+        // 9. If learner finished the course, trigger reward distribution
+        if new_progress == course.total_modules {
+            // Fetch RewardPool address from instance storage
+            let reward_pool_addr: Address = env
+                .storage()
+                .instance()
+                .get(&DataKey::RewardPool)
+                .expect("RewardPool not set");
+
+            let reward_pool = RewardPoolClient::new(&env, &reward_pool_addr);
+
+            // Base reward in token's smallest unit (e.g., 10 USDC)
+            let base_reward: i128 = 10_0000000;
+
+            reward_pool.distribute_reward(&env.current_contract_address(), &learner, &base_reward);
+        }
     }
 }
 

contracts/course-registry/src/test.rs

@@ -6,6 +6,8 @@ use soroban_sdk::{
 };
 
 use crate::{CourseRegistry, CourseRegistryClient, DataKey};
+use reward_pool::RewardPoolClient;
+use soroban_sdk::token;
 
 // ── Helpers ───────────────────────────────────────────────────────────────────
 
@@ -563,3 +565,86 @@ fn test_get_progress_tracks_completion() {
     client.complete_module(&admin, &learner, &course_id);
     assert_eq!(client.get_progress(&learner, &course_id), 3);
 }
+
+#[test]
+fn test_complete_module_triggers_reward_success() {
+    let env = Env::default();
+    env.mock_all_auths();
+
+    // Register CourseRegistry
+    let cr_contract_id = env.register(CourseRegistry, ());
+    let cr_client = CourseRegistryClient::new(&env, &cr_contract_id);
+
+    // Register RewardPool
+    let rp_contract_id = env.register(reward_pool::RewardPool, ());
+    let rp_client = RewardPoolClient::new(&env, &rp_contract_id);
+
+    let admin = Address::generate(&env);
+    let instructor = Address::generate(&env);
+    let learner = Address::generate(&env);
+
+    // Create a mock token and initialize reward pool
+    let token_id = env.register_stellar_asset_contract_v2(admin.clone());
+    cr_client.initialize(&admin);
+    rp_client.initialize(&admin, &token_id.address());
+
+    // Set reward pool address on CourseRegistry and whitelist CourseRegistry in RewardPool
+    cr_client.set_reward_pool(&admin, &rp_client.address);
+    rp_client.add_approved_spender(&admin, &cr_client.address);
+
+    // Create course and enroll learner
+    let course_id = cr_client.create_course(&admin, &instructor, &3, &dummy_hash(&env));
+    cr_client.enroll(&learner, &course_id);
+
+    // Fund reward pool with tokens
+    let token_client = token::StellarAssetClient::new(&env, &token_id.address());
+    token_client.mint(&rp_client.address, &100000000i128);
+
+    // Complete modules - final completion should trigger distribution
+    cr_client.complete_module(&admin, &learner, &course_id);
+    cr_client.complete_module(&admin, &learner, &course_id);
+    cr_client.complete_module(&admin, &learner, &course_id);
+
+    // Verify learner received base reward (10_0000000)
+    assert_eq!(token_client.balance(&learner), 10_0000000i128);
+}
+
+#[test]
+#[should_panic(expected = "Caller is not an authorized spender")]
+fn test_complete_module_fails_when_not_whitelisted() {
+    let env = Env::default();
+    env.mock_all_auths();
+
+    // Register CourseRegistry
+    let cr_contract_id = env.register(CourseRegistry, ());
+    let cr_client = CourseRegistryClient::new(&env, &cr_contract_id);
+
+    // Register RewardPool
+    let rp_contract_id = env.register(reward_pool::RewardPool, ());
+    let rp_client = RewardPoolClient::new(&env, &rp_contract_id);
+
+    let admin = Address::generate(&env);
+    let instructor = Address::generate(&env);
+    let learner = Address::generate(&env);
+
+    // Create a mock token and initialize reward pool
+    let token_id = env.register_stellar_asset_contract_v2(admin.clone());
+    cr_client.initialize(&admin);
+    rp_client.initialize(&admin, &token_id.address());
+
+    // Set reward pool address on CourseRegistry but DO NOT whitelist CourseRegistry in RewardPool
+    cr_client.set_reward_pool(&admin, &rp_client.address);
+
+    // Create course and enroll learner
+    let course_id = cr_client.create_course(&admin, &instructor, &3, &dummy_hash(&env));
+    cr_client.enroll(&learner, &course_id);
+
+    // Fund reward pool with tokens
+    let token_client = token::StellarAssetClient::new(&env, &token_id.address());
+    token_client.mint(&rp_client.address, &100000000i128);
+
+    // Complete modules - final completion should attempt distribution and panic
+    cr_client.complete_module(&admin, &learner, &course_id);
+    cr_client.complete_module(&admin, &learner, &course_id);
+    cr_client.complete_module(&admin, &learner, &course_id);
+}

contracts/course-registry/src/types.rs

@@ -16,4 +16,5 @@ pub enum DataKey {
     Progress(Address, u32),
     CourseCount,
     Admin,
+        RewardPool,
 }