feat(contracts): implement content flagging mechanism

contracts/geev-core/src/governance.rs

@@ -0,0 +1,64 @@
+use soroban_sdk::{contract, contractevent, contractimpl, Address, Env};
+
+use crate::types::{DataKey, Error};
+
+#[contract]
+pub struct GovernanceContract;
+
+#[contractevent]
+pub struct ContentFlagged {
+    #[topic]
+    target_id: u64,
+    user: Address,
+    count: u32,
+}
+
+#[contractimpl]
+impl GovernanceContract {
+    /// Flag a piece of content (Giveaway or HelpRequest) by its ID.
+    /// Each user may only flag a given ID once.
+    pub fn flag_content(env: Env, user: Address, target_id: u64) -> Result<(), Error> {
+        // 1. Verify caller signature
+        user.require_auth();
+
+        // 2. Prevent duplicate flags from the same user
+        let flag_key = DataKey::FlagRecord(target_id, user.clone());
+        if env.storage().persistent().has(&flag_key) {
+            return Err(Error::AlreadyFlagged);
+        }
+
+        // 3. Record that this user has flagged this ID
+        env.storage().persistent().set(&flag_key, &true);
+
+        // 4. Increment the total flag count for this ID
+        let count_key = DataKey::FlagCount(target_id);
+        let current: u32 = env.storage().persistent().get(&count_key).unwrap_or(0);
+        let new_count = current.checked_add(1).ok_or(Error::ArithmeticOverflow)?;
+        env.storage().persistent().set(&count_key, &new_count);
+
+        // 5. Emit "ContentFlagged" event: topics = (name, target_id), data = (user, total_flags)
+        ContentFlagged {
+            target_id,
+            user,
+            count: new_count,
+        }
+        .publish(&env);
+
+        Ok(())
+    }
+
+    /// Returns the total number of flags for a given content ID.
+    pub fn get_flag_count(env: Env, target_id: u64) -> u32 {
+        env.storage()
+            .persistent()
+            .get(&DataKey::FlagCount(target_id))
+            .unwrap_or(0)
+    }
+
+    /// Returns whether a specific user has already flagged a given content ID.
+    pub fn has_flagged(env: Env, user: Address, target_id: u64) -> bool {
+        env.storage()
+            .persistent()
+            .has(&DataKey::FlagRecord(target_id, user))
+    }
+}

contracts/geev-core/src/lib.rs

@@ -3,6 +3,7 @@
 pub mod access;
 pub mod admin;
 pub mod giveaway;
+pub mod governance;
 pub mod mutual_aid;
 pub mod profile;
 pub mod types;
@@ -15,6 +16,7 @@ pub use crate::admin::AdminContract;
 pub use crate::admin::AdminContractClient;
 pub use crate::giveaway::GiveawayContract;
 pub use crate::giveaway::GiveawayContractClient;
+pub use crate::governance::{GovernanceContract, GovernanceContractClient};
 pub use crate::mutual_aid::MutualAidContract;
 pub use crate::mutual_aid::MutualAidContractClient;
 pub use crate::profile::{ProfileContract, ProfileContractClient};

contracts/geev-core/src/test.rs

@@ -1,6 +1,7 @@
 use crate::access::check_admin;
 use crate::admin::{AdminContract, AdminContractClient};
 use crate::giveaway::{GiveawayContract, GiveawayContractClient};
+use crate::governance::{GovernanceContract, GovernanceContractClient};
 use crate::mutual_aid::{MutualAidContract, MutualAidContractClient};
 use crate::profile::{ProfileContract, ProfileContractClient};
 use crate::types::{DataKey, HelpRequest, HelpRequestStatus};
@@ -1312,3 +1313,88 @@ fn test_donate_event_emits_exact_amount_and_total() {
         "DonationReceived event did not contain the exact amount_donated and new_total_raised"
     );
 }
+
+// ── Governance / flag_content tests ──────────────────────────────────────────
+#[test]
+fn test_flag_content_increments_count() {
+    let env = Env::default();
+    env.mock_all_auths();
+
+    let contract_id = env.register(GovernanceContract, ());
+    let client = GovernanceContractClient::new(&env, &contract_id);
+
+    let user = Address::generate(&env);
+    let target_id: u64 = 42;
+
+    assert_eq!(client.get_flag_count(&target_id), 0);
+
+    client.flag_content(&user, &target_id);
+
+    assert_eq!(client.get_flag_count(&target_id), 1);
+}
+
+#[test]
+fn test_flag_content_multiple_users() {
+    let env = Env::default();
+    env.mock_all_auths();
+
+    let contract_id = env.register(GovernanceContract, ());
+    let client = GovernanceContractClient::new(&env, &contract_id);
+
+    let user_a = Address::generate(&env);
+    let user_b = Address::generate(&env);
+    let target_id: u64 = 7;
+
+    client.flag_content(&user_a, &target_id);
+    client.flag_content(&user_b, &target_id);
+
+    assert_eq!(client.get_flag_count(&target_id), 2);
+    assert!(client.has_flagged(&user_a, &target_id));
+    assert!(client.has_flagged(&user_b, &target_id));
+}
+
+#[test]
+#[should_panic]
+fn test_flag_content_duplicate_panics() {
+    let env = Env::default();
+    env.mock_all_auths();
+
+    let contract_id = env.register(GovernanceContract, ());
+    let client = GovernanceContractClient::new(&env, &contract_id);
+
+    let user = Address::generate(&env);
+    let target_id: u64 = 1;
+
+    client.flag_content(&user, &target_id);
+    // Second flag from the same user must panic with AlreadyFlagged
+    client.flag_content(&user, &target_id);
+}
+
+#[test]
+fn test_has_flagged_returns_false_before_flag() {
+    let env = Env::default();
+    env.mock_all_auths();
+
+    let contract_id = env.register(GovernanceContract, ());
+    let client = GovernanceContractClient::new(&env, &contract_id);
+
+    let user = Address::generate(&env);
+    assert!(!client.has_flagged(&user, &99u64));
+}
+
+#[test]
+fn test_flag_counts_are_independent_per_id() {
+    let env = Env::default();
+    env.mock_all_auths();
+
+    let contract_id = env.register(GovernanceContract, ());
+    let client = GovernanceContractClient::new(&env, &contract_id);
+
+    let user = Address::generate(&env);
+
+    client.flag_content(&user, &1u64);
+
+    // ID 2 should still be at 0
+    assert_eq!(client.get_flag_count(&2u64), 0);
+    assert_eq!(client.get_flag_count(&1u64), 1);
+}

contracts/geev-core/src/types.rs

@@ -22,6 +22,7 @@ pub enum Error {
     HelpRequestAlreadyExists = 16,
     TokenNotSupported = 17,
     UsernameTaken = 18,
+    AlreadyFlagged = 19,
 }
 
 #[derive(Clone, PartialEq, Eq)]
@@ -83,6 +84,8 @@ pub enum DataKey {
     AllowedToken(Address),
     Profile(Address),
     Username(String),
+    FlagRecord(u64, Address),
+    FlagCount(u64),
 }
 
 #[derive(Clone, Debug, Eq, PartialEq)]