feat(purgatory): add broken purgatory implementation

1 files changed, 149 insertions, 0 deletions

diff --git a/src/nostr/policy/pr_event.rs b/src/nostr/policy/pr_event.rs
index 53da369..c7602b0 100644
--- a/src/nostr/policy/pr_event.rs
+++ b/src/nostr/policy/pr_event.rs
@@ -19,6 +19,155 @@ impl PrEventPolicy {
         Self { ctx }
     }
 
+    /// Check if git data exists for a PR event
+    ///
+    /// This checks:
+    /// 1. If a placeholder exists (git-data-first scenario)
+    /// 2. If the commit exists in any relevant repository
+    ///
+    /// # Returns
+    /// - `Ok(true)` if git data ready (either placeholder found or commit exists)
+    /// - `Ok(false)` if git data missing (should add to purgatory)
+    /// - `Err(msg)` on errors
+    pub async fn check_git_data_exists(&self, event: &Event) -> Result<bool, String> {
+        let event_id = event.id.to_hex();
+
+        // Extract the `c` tag (commit hash) from the PR event
+        let commit = event.tags.iter().find_map(|tag| {
+            let tag_vec = tag.clone().to_vec();
+            if tag_vec.len() >= 2 && tag_vec[0] == "c" {
+                Some(tag_vec[1].clone())
+            } else {
+                None
+            }
+        });
+
+        let commit = match commit {
+            Some(c) => c,
+            None => {
+                return Err(format!("PR event {} has no 'c' tag", event_id));
+            }
+        };
+
+        // Check for placeholder first (git-data-first scenario)
+        if let Some(placeholder_commit) = self.ctx.purgatory.find_pr_placeholder(&event_id) {
+            if placeholder_commit == commit {
+                // Perfect match - git data arrived first with matching commit
+                tracing::debug!(
+                    "Found matching placeholder for PR event {} with commit {}",
+                    event_id,
+                    commit
+                );
+                // Remove placeholder - event processing will continue normally
+                self.ctx.purgatory.remove_pr(&event_id);
+                return Ok(true);
+            } else {
+                // Placeholder has different commit - incoming event supersedes
+                tracing::info!(
+                    "PR event {} supersedes placeholder: event expects commit {}, placeholder has {}",
+                    event_id,
+                    commit,
+                    placeholder_commit
+                );
+                // Remove placeholder with old commit data
+                self.ctx.purgatory.remove_pr(&event_id);
+                // TODO: Also remove git data (refs/nostr/<event-id>) - Phase 5
+                // Fall through to check if new commit exists
+            }
+        }
+
+        // Check if commit exists in any repository referenced by this PR
+        // Extract ALL `a` tags (repository references) from the PR event
+        let repo_refs: Vec<String> = event
+            .tags
+            .iter()
+            .filter_map(|tag| {
+                let tag_vec = tag.clone().to_vec();
+                if tag_vec.len() >= 2 && tag_vec[0] == "a" && tag_vec[1].starts_with("30617:") {
+                    Some(tag_vec[1].clone())
+                } else {
+                    None
+                }
+            })
+            .collect();
+
+        if repo_refs.is_empty() {
+            // No repo references - cannot check git data
+            // This is unusual but let it through (other validation will catch issues)
+            return Ok(true);
+        }
+
+        // Check each repository to see if commit exists
+        for repo_ref in repo_refs {
+            // Parse the repo reference: 30617:<pubkey>:<identifier>
+            let parts: Vec<&str> = repo_ref.split(':').collect();
+            if parts.len() < 3 {
+                continue;
+            }
+
+            let repo_pubkey = match PublicKey::from_hex(parts[1]) {
+                Ok(pk) => pk,
+                Err(_) => continue,
+            };
+            let identifier = parts[2];
+
+            // Look up repository announcement to get the npub for path
+            let filter = Filter::new()
+                .kind(Kind::from(KIND_REPOSITORY_ANNOUNCEMENT))
+                .author(repo_pubkey)
+                .custom_tag(
+                    SingleLetterTag::lowercase(Alphabet::D),
+                    identifier.to_string(),
+                );
+
+            let announcements: Vec<Event> = match self.ctx.database.query(filter).await {
+                Ok(events) => events.into_iter().collect(),
+                Err(e) => {
+                    tracing::warn!(
+                        "Failed to query for repository announcement for PR {}: {}",
+                        event_id,
+                        e
+                    );
+                    continue;
+                }
+            };
+
+            if announcements.is_empty() {
+                continue;
+            }
+
+            // Check each matching announcement
+            for announcement_event in announcements {
+                let announcement = match RepositoryAnnouncement::from_event(announcement_event) {
+                    Ok(a) => a,
+                    Err(_) => continue,
+                };
+
+                // Build repository path
+                let repo_path = self.ctx.git_data_path.join(announcement.repo_path());
+
+                // Check if commit exists
+                if git::commit_exists(&repo_path, &commit) {
+                    tracing::debug!(
+                        "Found commit {} for PR event {} in repository {}",
+                        commit,
+                        event_id,
+                        repo_path.display()
+                    );
+                    return Ok(true);
+                }
+            }
+        }
+
+        // No git data found - should add to purgatory
+        tracing::debug!(
+            "No git data found for PR event {} with commit {}",
+            event_id,
+            commit
+        );
+        Ok(false)
+    }
+
     /// Validate refs/nostr/<event-id> ref against a PR or PR Update event's `c` tag
     ///
     /// When a PR event (kind 1618) or PR Update event (kind 1619) is received,