feature/issue-102-get-top-contributor-for-campaign

contract/contract/src/base/types.rs

@@ -127,6 +127,8 @@ pub struct CampaignMetrics {
     pub total_raised: i128,
     pub contributor_count: u32,
     pub last_donation_at: u64,
+    pub max_donation: i128,
+    pub top_contributor: Option<Address>,
 }
 
 impl Default for CampaignMetrics {
@@ -141,6 +143,8 @@ impl CampaignMetrics {
             total_raised: 0,
             contributor_count: 0,
             last_donation_at: 0,
+            max_donation: 0,
+            top_contributor: None,
         }
     }
 }

contract/contract/src/crowdfunding.rs

@@ -172,6 +172,25 @@ impl CrowdfundingTrait for CrowdfundingContract {
             .unwrap_or(0)
     }
 
+    fn get_top_contributor_for_campaign(
+        env: Env,
+        campaign_id: BytesN<32>,
+    ) -> Result<Address, CrowdfundingError> {
+        // Validate campaign exists
+        Self::get_campaign(env.clone(), campaign_id.clone())?;
+
+        let metrics_key = StorageKey::CampaignMetrics(campaign_id);
+        let metrics: CampaignMetrics = env
+            .storage()
+            .instance()
+            .get(&metrics_key)
+            .unwrap_or_default();
+
+        metrics
+            .top_contributor
+            .ok_or(CrowdfundingError::CampaignNotFound)
+    }
+
     fn get_all_campaigns(env: Env) -> Vec<BytesN<32>> {
         env.storage()
             .instance()
@@ -349,6 +368,12 @@ impl CrowdfundingTrait for CrowdfundingContract {
         metrics.total_raised += amount;
         metrics.last_donation_at = env.ledger().timestamp();
 
+        // Track top contributor (whale donor)
+        if amount > metrics.max_donation {
+            metrics.max_donation = amount;
+            metrics.top_contributor = Some(donor.clone());
+        }
+
         // Track unique donor
         let donor_key = StorageKey::CampaignDonor(campaign_id.clone(), donor.clone());
         if !env.storage().instance().has(&donor_key) {

contract/contract/src/interfaces/crowdfunding.rs

@@ -87,6 +87,11 @@ pub trait CrowdfundingTrait {
 
     fn get_global_raised_total(env: Env) -> i128;
 
+    fn get_top_contributor_for_campaign(
+        env: Env,
+        campaign_id: BytesN<32>,
+    ) -> Result<Address, CrowdfundingError>;
+
     fn initialize(
         env: Env,
         admin: Address,