feat: add campaign comment system via off-chain attestation (#542)

CHANGELOG.md

@@ -6,6 +6,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
 
+### Added
+- Campaign comment system via off-chain attestation. Added `add_campaign_comment` to emit comment hashes, and `remove_campaign_comment` to flag comments as removed on-chain for moderation (#542).
+
 ### Fixed
 
 - `cancel_campaign` now rejects with `GoalMetCancellationNotAllowed` when `amount_raised >= funding_goal` and funds have not yet been withdrawn, preventing rug-pull-adjacent behaviour where a creator could cancel after reaching the goal and force all contributors to self-serve refunds (#164).

src/admin.rs

@@ -543,4 +543,4 @@ impl ProofOfHeartContract {
         let cap_key = DataKey::CategoryMaxGoalCap(category);
         env.storage().persistent().get(&cap_key)
     }
-}
+}

src/campaigns/comments.rs

@@ -0,0 +1,69 @@
+use soroban_sdk::{Address, Env, String};
+
+use crate::errors::Error;
+use crate::lifecycle::{get_campaign_or_error, require_not_paused};
+use crate::storage::{
+    bump_instance_ttl, get_admin, get_campaign_comment_count, is_comment_removed,
+    set_campaign_comment_count, set_comment_removed,
+};
+
+pub(crate) fn add_campaign_comment(
+    env: &Env,
+    campaign_id: u32,
+    commenter: Address,
+    comment_hash: String,
+) -> Result<u32, Error> {
+    commenter.require_auth();
+    require_not_paused(env)?;
+
+    // Just verify the campaign exists
+    let _campaign = get_campaign_or_error(env, campaign_id)?;
+
+    bump_instance_ttl(env);
+
+    let count = get_campaign_comment_count(env, campaign_id);
+    let comment_id = count.checked_add(1).ok_or(Error::Overflow)?;
+
+    set_campaign_comment_count(env, campaign_id, comment_id);
+
+    env.events().publish(
+        ("campaign_comment_added", campaign_id, comment_id),
+        (commenter, comment_hash),
+    );
+
+    Ok(comment_id)
+}
+
+pub(crate) fn remove_campaign_comment(
+    env: &Env,
+    campaign_id: u32,
+    comment_id: u32,
+    caller: Address,
+) -> Result<(), Error> {
+    caller.require_auth();
+    require_not_paused(env)?;
+
+    let campaign = get_campaign_or_error(env, campaign_id)?;
+
+    // Only the campaign creator or the admin can remove comments.
+    if caller != campaign.creator && caller != get_admin(env) {
+        return Err(Error::NotAuthorized);
+    }
+
+    let count = get_campaign_comment_count(env, campaign_id);
+    if comment_id == 0 || comment_id > count {
+        return Err(Error::InvalidCommentId);
+    }
+
+    if is_comment_removed(env, campaign_id, comment_id) {
+        return Err(Error::CommentAlreadyRemoved);
+    }
+
+    bump_instance_ttl(env);
+    set_comment_removed(env, campaign_id, comment_id);
+
+    env.events()
+        .publish(("campaign_comment_removed", campaign_id, comment_id), caller);
+
+    Ok(())
+}

src/campaigns/mod.rs

@@ -3,3 +3,4 @@ pub(crate) mod create;
 pub(crate) mod transfer;
 pub(crate) mod update;
 pub(crate) mod withdraw;
+pub(crate) mod comments;

src/errors.rs

@@ -148,6 +148,10 @@ impl Error {
             Error::InvalidStateTransition => "InvalidStateTransition",
             Error::CampaignAlreadyBookmarked => "CampaignAlreadyBookmarked",
             Error::CampaignNotBookmarked => "CampaignNotBookmarked",
+    /// The specified comment ID does not exist.
+    InvalidCommentId = 46,
+    /// The specified comment has already been removed.
+    CommentAlreadyRemoved = 47,
         }
     }
 }

src/lib.rs

@@ -169,6 +169,26 @@ impl ProofOfHeart {
         campaigns::update::extend_campaign_deadline(&env, campaign_id, additional_days)
     }
 
+    // ── Comments ──────────────────────────────────────────────────────────────
+
+    pub fn add_campaign_comment(
+        env: Env,
+        campaign_id: u32,
+        commenter: Address,
+        comment_hash: String,
+    ) -> Result<u32, Error> {
+        campaigns::comments::add_campaign_comment(&env, campaign_id, commenter, comment_hash)
+    }
+
+    pub fn remove_campaign_comment(
+        env: Env,
+        campaign_id: u32,
+        comment_id: u32,
+        caller: Address,
+    ) -> Result<(), Error> {
+        campaigns::comments::remove_campaign_comment(&env, campaign_id, comment_id, caller)
+    }
+
     // ── Campaign ownership transfer ───────────────────────────────────────────
 
     pub fn initiate_campaign_transfer(
@@ -676,4 +696,4 @@ impl ProofOfHeartContract {
             None => all_campaigns,
         }
     }
-}
+}

src/storage.rs

@@ -182,6 +182,16 @@ pub enum BookmarkKey {
     SavedCampaigns(Address),
 }
 
+/// Keys for campaign comments.
+#[contracttype]
+pub enum CommentKey {
+    /// Tracks the total number of comments for a campaign.
+    CampaignCommentCount(u32),
+    /// Flags whether a specific comment ID has been removed. Key is (campaign_id, comment_id).
+    CommentRemoved(u32, u32),
+}
+
+
 // ── Campaign ──────────────────────────────────────────────────────────────────
 
 /// Returns the campaign for the given ID.
@@ -694,6 +704,27 @@ pub fn get_version(env: &Env) -> u32 {
         .unwrap_or(0)
 }
 
+
+// ── Comments ──────────────────────────────────────────────────────────────────
+
+pub fn get_campaign_comment_count(env: &Env, campaign_id: u32) -> u32 {
+    let key = CommentKey::CampaignCommentCount(campaign_id);
+    env.storage().persistent().get(&key).unwrap_or(0)
+}
+
+pub fn set_campaign_comment_count(env: &Env, campaign_id: u32, count: u32) {
+    persistent_set!(env, CommentKey::CampaignCommentCount(campaign_id), &count);
+}
+
+pub fn is_comment_removed(env: &Env, campaign_id: u32, comment_id: u32) -> bool {
+    let key = CommentKey::CommentRemoved(campaign_id, comment_id);
+    env.storage().persistent().get(&key).unwrap_or(false)
+}
+
+pub fn set_comment_removed(env: &Env, campaign_id: u32, comment_id: u32) {
+    persistent_set!(env, CommentKey::CommentRemoved(campaign_id, comment_id), &true);
+}
+
 // ── Total raised global ───────────────────────────────────────────────────────
 
 /// Returns the total amount raised across all campaigns.

src/tests/mod.rs

@@ -22,3 +22,4 @@ mod test_revenue_deposit;
 mod test_voting;
 mod test_voting_verify;
 mod test_withdrawals;
+mod test_comments;

src/tests/test_campaign_update.rs

@@ -59,10 +59,13 @@ fn test_update_campaign_emits_title_and_description() {
 
     let events = env.events().all();
     let last_event = events.last().unwrap();
-    let payload: (String, String) = soroban_sdk::FromVal::from_val(&env, &last_event.2);
+    let payload: (String, String, String, String) =
+        soroban_sdk::FromVal::from_val(&env, &last_event.2);
 
-    assert_eq!(payload.0, new_title);
-    assert_eq!(payload.1, new_desc);
+    assert_eq!(payload.0, String::from_str(&env, "Original Title"));
+    assert_eq!(payload.1, String::from_str(&env, "Original Description"));
+    assert_eq!(payload.2, new_title);
+    assert_eq!(payload.3, new_desc);
 }
 
 #[test]
@@ -94,9 +97,12 @@ fn test_update_campaign_event_tracks_latest_description() {
 
     let events = env.events().all();
     let last_event = events.last().unwrap();
-    let payload: (String, String) = soroban_sdk::FromVal::from_val(&env, &last_event.2);
-    assert_eq!(payload.0, String::from_str(&env, "Title V3"));
-    assert_eq!(payload.1, String::from_str(&env, "Description V3"));
+    let payload: (String, String, String, String) =
+        soroban_sdk::FromVal::from_val(&env, &last_event.2);
+    assert_eq!(payload.0, String::from_str(&env, "Title V2"));
+    assert_eq!(payload.1, String::from_str(&env, "Description V2"));
+    assert_eq!(payload.2, String::from_str(&env, "Title V3"));
+    assert_eq!(payload.3, String::from_str(&env, "Description V3"));
 }
 
 #[test]

src/tests/test_comments.rs

@@ -0,0 +1,79 @@
+#![cfg(test)]
+extern crate std;
+
+use super::helpers::{setup_env, setup_env_with_active_campaign};
+use crate::ProofOfHeartContractClient;
+use soroban_sdk::{testutils::Events, String};
+
+#[test]
+fn test_add_and_remove_comment() {
+    let (env, contract_id, _, creator, _) = setup_env_with_active_campaign(100);
+    let client = ProofOfHeartContractClient::new(&env, &contract_id);
+
+    let commenter = soroban_sdk::Address::generate(&env);
+    let comment_hash = String::from_str(&env, "QmHash123");
+
+    // Add comment
+    let comment_id = client.add_campaign_comment(&1, &commenter, &comment_hash);
+    assert_eq!(comment_id, 1);
+
+    // Verify events
+    let events = env.events().all();
+    let mut found_added = false;
+    for (contract, topic, data) in events.iter() {
+        if contract == contract_id {
+            if let Ok(t) = topic.clone().try_into_val(&env) {
+                let t: soroban_sdk::Vec<soroban_sdk::Val> = t;
+                if t.len() == 3 {
+                    let event_name: String = t.get(0).unwrap().try_into_val(&env).unwrap();
+                    if event_name == String::from_str(&env, "campaign_comment_added") {
+                        found_added = true;
+                        let cid: u32 = t.get(2).unwrap().try_into_val(&env).unwrap();
+                        assert_eq!(cid, 1);
+                    }
+                }
+            }
+        }
+    }
+    assert!(found_added);
+
+    // Remove comment by creator
+    client.remove_campaign_comment(&1, &comment_id, &creator);
+
+    // Verify remove event
+    let events = env.events().all();
+    let mut found_removed = false;
+    for (contract, topic, data) in events.iter() {
+        if contract == contract_id {
+            if let Ok(t) = topic.clone().try_into_val(&env) {
+                let t: soroban_sdk::Vec<soroban_sdk::Val> = t;
+                if t.len() == 3 {
+                    let event_name: String = t.get(0).unwrap().try_into_val(&env).unwrap();
+                    if event_name == String::from_str(&env, "campaign_comment_removed") {
+                        found_removed = true;
+                    }
+                }
+            }
+        }
+    }
+    assert!(found_removed);
+
+    // Ensure double remove fails
+    let res = client.try_remove_campaign_comment(&1, &comment_id, &creator);
+    assert!(res.is_err()); // CommentAlreadyRemoved
+}
+
+#[test]
+fn test_remove_comment_unauthorized() {
+    let (env, contract_id, _, creator, _) = setup_env_with_active_campaign(100);
+    let client = ProofOfHeartContractClient::new(&env, &contract_id);
+
+    let commenter = soroban_sdk::Address::generate(&env);
+    let comment_hash = String::from_str(&env, "QmHash123");
+
+    let comment_id = client.add_campaign_comment(&1, &commenter, &comment_hash);
+
+    let stranger = soroban_sdk::Address::generate(&env);
+    let res = client.try_remove_campaign_comment(&1, &comment_id, &stranger);
+    assert!(res.is_err()); // NotAuthorized
+}