feat(faces): PeopleService — identity clustering + use cases

Phase 2 increment 4:
- recluster(user): union-find connected-components over the user's face
  embeddings (cosine threshold); groups of >= min_faces become persons, and
  an existing person's name is preserved across reclusters. O(n^2) — fine
  for moderate libraries; an ANN index is the documented scale-up.
- caller_id-scoped use cases for the HTTP layer: list_people (non-empty
  clusters, cover thumbnail, most-photographed first), person_photos,
  faces_for_file, rename, hide, merge, and delete_all (right to erasure).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JW6ghFMDtnRYuYNzZhb47M
This commit is contained in:
Claude
2026-06-19 11:40:33 +00:00
parent 248ad70f01
commit de95de013d
2 changed files with 272 additions and 0 deletions
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@@ -20,6 +20,7 @@ pub mod magic_link_invite_service;
pub mod music_service;
pub mod nextcloud_file_id_service;
pub mod nextcloud_login_flow_service;
pub mod people_service;
pub mod places_service;
pub mod recent_service;
pub mod recipient_notification_service;
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@@ -0,0 +1,271 @@
//! People (faces) use cases: identity clustering + the read/mutation methods
//! the HTTP layer calls.
//!
//! Clustering is a full re-cluster over the user's faces: a union-find groups
//! faces whose embeddings are within a cosine threshold (connected
//! components), and groups of at least `min_faces` become a "person". This is
//! O(n²) in the user's face count — fine for moderate libraries; an ANN index
//! (pgvector/VectorChord) is the documented scale-up.
//!
//! Strictly user-scoped (the repository filters by user), so — like
//! `RecentService` / `PlacesService` — no `AuthorizationEngine` check is
//! needed: the `caller_id` parameter is the access scope.
use std::collections::HashMap;
use std::sync::Arc;
use chrono::Utc;
use uuid::Uuid;
use crate::application::dtos::people_dto::{FaceBoxDto, PersonDto};
use crate::application::ports::face_ports::FaceRepository;
use crate::common::errors::DomainError;
use crate::domain::entities::face::Person;
use crate::infrastructure::repositories::pg::FacePgRepository;
/// Cosine similarity of two equal-length vectors. Embeddings are produced
/// L2-normalized, so this is ~a dot product; we normalize anyway for safety.
fn cosine(a: &[f32], b: &[f32]) -> f32 {
if a.len() != b.len() || a.is_empty() {
return 0.0;
}
let (mut dot, mut na, mut nb) = (0.0f32, 0.0f32, 0.0f32);
for (&x, &y) in a.iter().zip(b.iter()) {
dot += x * y;
na += x * x;
nb += y * y;
}
if na == 0.0 || nb == 0.0 {
return 0.0;
}
dot / (na.sqrt() * nb.sqrt())
}
/// Disjoint-set with path-halving + union by rank.
struct UnionFind {
parent: Vec<usize>,
rank: Vec<usize>,
}
impl UnionFind {
fn new(n: usize) -> Self {
Self {
parent: (0..n).collect(),
rank: vec![0; n],
}
}
fn find(&mut self, mut x: usize) -> usize {
while self.parent[x] != x {
self.parent[x] = self.parent[self.parent[x]];
x = self.parent[x];
}
x
}
fn union(&mut self, a: usize, b: usize) {
let (ra, rb) = (self.find(a), self.find(b));
if ra == rb {
return;
}
match self.rank[ra].cmp(&self.rank[rb]) {
std::cmp::Ordering::Less => self.parent[ra] = rb,
std::cmp::Ordering::Greater => self.parent[rb] = ra,
std::cmp::Ordering::Equal => {
self.parent[rb] = ra;
self.rank[ra] += 1;
}
}
}
}
pub struct PeopleService {
repo: Arc<FacePgRepository>,
/// Min cosine similarity to link two faces into the same identity.
cluster_threshold: f32,
/// Min faces in a cluster before it becomes a named-able "person".
min_faces: usize,
}
impl PeopleService {
pub fn new(repo: Arc<FacePgRepository>) -> Self {
Self {
repo,
cluster_threshold: 0.5,
min_faces: 3,
}
}
/// Re-cluster a user's faces. Returns the number of new persons created.
pub async fn recluster(&self, user_id: Uuid) -> Result<usize, DomainError> {
let faces = self.repo.faces_for_user(user_id).await?;
let n = faces.len();
if n == 0 {
return Ok(0);
}
let mut uf = UnionFind::new(n);
for i in 0..n {
for j in (i + 1)..n {
if cosine(&faces[i].embedding, &faces[j].embedding) >= self.cluster_threshold {
uf.union(i, j);
}
}
}
let mut groups: HashMap<usize, Vec<usize>> = HashMap::new();
for i in 0..n {
let root = uf.find(i);
groups.entry(root).or_default().push(i);
}
let mut created = 0usize;
for idxs in groups.into_values() {
if idxs.len() < self.min_faces {
// Too small to be a person — leave/reset these faces unassigned.
for &i in &idxs {
if faces[i].person_id.is_some() {
self.repo.assign_person(faces[i].id, None).await?;
}
}
continue;
}
// Reuse an existing person on this cluster (preserves a user's name)
// or mint a new one.
let existing = idxs.iter().find_map(|&i| faces[i].person_id);
let person_id = match existing {
Some(pid) => pid,
None => {
let pid = Uuid::new_v4();
let person = Person {
id: pid,
user_id,
display_name: None,
cover_face_id: Some(faces[idxs[0]].id),
is_hidden: false,
created_at: Utc::now(),
};
self.repo.create_person(&person).await?;
created += 1;
pid
}
};
for &i in &idxs {
if faces[i].person_id != Some(person_id) {
self.repo
.assign_person(faces[i].id, Some(person_id))
.await?;
}
}
let _ = self
.repo
.set_person_cover(person_id, faces[idxs[0]].id)
.await;
}
Ok(created)
}
/// People (non-empty clusters), most-photographed first.
pub async fn list_people(&self, caller_id: Uuid) -> Result<Vec<PersonDto>, DomainError> {
let persons = self.repo.persons_for_user(caller_id).await?;
let faces = self.repo.faces_for_user(caller_id).await?;
let mut count: HashMap<Uuid, i64> = HashMap::new();
let mut face_file: HashMap<Uuid, Uuid> = HashMap::new();
for f in &faces {
if let Some(pid) = f.person_id {
*count.entry(pid).or_default() += 1;
}
face_file.insert(f.id, f.file_id);
}
let mut out: Vec<PersonDto> = persons
.into_iter()
.filter_map(|p| {
let c = count.get(&p.id).copied().unwrap_or(0);
if c == 0 {
return None; // hide empty clusters (e.g. after a merge)
}
let cover_file_id = p
.cover_face_id
.and_then(|fid| face_file.get(&fid).copied())
.map(|u| u.to_string());
Some(PersonDto {
id: p.id.to_string(),
name: p.display_name,
cover_file_id,
face_count: c,
is_hidden: p.is_hidden,
})
})
.collect();
out.sort_by(|a, b| b.face_count.cmp(&a.face_count));
Ok(out)
}
/// File ids of a person's photos (most recent first).
pub async fn person_photos(
&self,
caller_id: Uuid,
person_id: Uuid,
) -> Result<Vec<String>, DomainError> {
let files = self.repo.files_for_person(caller_id, person_id).await?;
Ok(files.into_iter().map(|u| u.to_string()).collect())
}
/// Face boxes within a photo (for lightbox tagging), caller-scoped.
pub async fn faces_for_file(
&self,
caller_id: Uuid,
file_id: Uuid,
) -> Result<Vec<FaceBoxDto>, DomainError> {
let faces = self.repo.faces_for_file(file_id).await?;
Ok(faces
.into_iter()
.filter(|f| f.user_id == caller_id)
.map(|f| FaceBoxDto {
id: f.id.to_string(),
person_id: f.person_id.map(|u| u.to_string()),
x: f.bbox.x,
y: f.bbox.y,
w: f.bbox.w,
h: f.bbox.h,
})
.collect())
}
pub async fn rename_person(
&self,
caller_id: Uuid,
person_id: Uuid,
name: Option<String>,
) -> Result<(), DomainError> {
self.repo.rename_person(caller_id, person_id, name).await
}
pub async fn set_hidden(
&self,
caller_id: Uuid,
person_id: Uuid,
hidden: bool,
) -> Result<(), DomainError> {
self.repo
.set_person_hidden(caller_id, person_id, hidden)
.await
}
/// Merge `from` into `into` by reassigning all of `from`'s faces. The
/// now-empty `from` person is hidden by `list_people`.
pub async fn merge(&self, caller_id: Uuid, into: Uuid, from: Uuid) -> Result<(), DomainError> {
let faces = self.repo.faces_for_user(caller_id).await?;
for f in faces.into_iter().filter(|f| f.person_id == Some(from)) {
self.repo.assign_person(f.id, Some(into)).await?;
}
Ok(())
}
/// Erase all of the caller's face data (right to erasure / opt-out).
pub async fn delete_all(&self, caller_id: Uuid) -> Result<(), DomainError> {
self.repo.delete_all_for_user(caller_id).await
}
}