backend/app/api/v1/__init__.py

@@ -2,7 +2,16 @@
 
 from fastapi import APIRouter
 
-from app.api.v1 import auth, events, persons, relationships, trees, users
+from app.api.v1 import (
+    auth,
+    citations,
+    events,
+    persons,
+    relationships,
+    sources,
+    trees,
+    users,
+)
 
 api_router = APIRouter(prefix="/api/v1")
 api_router.include_router(auth.router)
@@ -11,3 +20,5 @@ api_router.include_router(trees.router)
 api_router.include_router(persons.router)
 api_router.include_router(events.router)
 api_router.include_router(relationships.router)
+api_router.include_router(sources.router)
+api_router.include_router(citations.router)

backend/app/api/v1/citations.py

@@ -0,0 +1,41 @@
+import uuid
+
+from fastapi import APIRouter, status
+
+from app.api.deps import CurrentUser, SessionDep
+from app.schemas.source import CitationCreate, CitationRead
+from app.services import citation_service, tree_service
+
+router = APIRouter(prefix="/trees", tags=["citations"])
+
+
+@router.post(
+    "/{tree_id}/citations", response_model=CitationRead, status_code=status.HTTP_201_CREATED
+)
+async def create_citation(
+    tree_id: uuid.UUID, data: CitationCreate, session: SessionDep, current: CurrentUser
+) -> CitationRead:
+    tree = await tree_service.get_tree(session, viewer_id=current.id, tree_id=tree_id)
+    citation = await citation_service.create_citation(
+        session, actor=current, tree=tree, **data.model_dump()
+    )
+    return CitationRead.model_validate(citation)
+
+
+@router.get("/{tree_id}/citations", response_model=list[CitationRead])
+async def list_citations(
+    tree_id: uuid.UUID, session: SessionDep, current: CurrentUser
+) -> list[CitationRead]:
+    tree = await tree_service.get_tree(session, viewer_id=current.id, tree_id=tree_id)
+    citations = await citation_service.list_citations(session, viewer_id=current.id, tree=tree)
+    return [CitationRead.model_validate(c) for c in citations]
+
+
+@router.delete("/{tree_id}/citations/{citation_id}", status_code=status.HTTP_204_NO_CONTENT)
+async def delete_citation(
+    tree_id: uuid.UUID, citation_id: uuid.UUID, session: SessionDep, current: CurrentUser
+) -> None:
+    tree = await tree_service.get_tree(session, viewer_id=current.id, tree_id=tree_id)
+    await citation_service.delete_citation(
+        session, actor=current, tree=tree, citation_id=citation_id
+    )

backend/app/api/v1/sources.py

@@ -0,0 +1,48 @@
+import uuid
+
+from fastapi import APIRouter, status
+
+from app.api.deps import CurrentUser, SessionDep
+from app.schemas.source import SourceCreate, SourceRead
+from app.services import source_service, tree_service
+
+router = APIRouter(prefix="/trees", tags=["sources"])
+
+
+@router.post("/{tree_id}/sources", response_model=SourceRead, status_code=status.HTTP_201_CREATED)
+async def create_source(
+    tree_id: uuid.UUID, data: SourceCreate, session: SessionDep, current: CurrentUser
+) -> SourceRead:
+    tree = await tree_service.get_tree(session, viewer_id=current.id, tree_id=tree_id)
+    source = await source_service.create_source(
+        session, actor=current, tree=tree, **data.model_dump()
+    )
+    return SourceRead.model_validate(source)
+
+
+@router.get("/{tree_id}/sources", response_model=list[SourceRead])
+async def list_sources(
+    tree_id: uuid.UUID, session: SessionDep, current: CurrentUser
+) -> list[SourceRead]:
+    tree = await tree_service.get_tree(session, viewer_id=current.id, tree_id=tree_id)
+    sources = await source_service.list_sources(session, viewer_id=current.id, tree=tree)
+    return [SourceRead.model_validate(s) for s in sources]
+
+
+@router.get("/{tree_id}/sources/{source_id}", response_model=SourceRead)
+async def get_source(
+    tree_id: uuid.UUID, source_id: uuid.UUID, session: SessionDep, current: CurrentUser
+) -> SourceRead:
+    tree = await tree_service.get_tree(session, viewer_id=current.id, tree_id=tree_id)
+    source = await source_service.get_source(
+        session, viewer_id=current.id, tree=tree, source_id=source_id
+    )
+    return SourceRead.model_validate(source)
+
+
+@router.delete("/{tree_id}/sources/{source_id}", status_code=status.HTTP_204_NO_CONTENT)
+async def delete_source(
+    tree_id: uuid.UUID, source_id: uuid.UUID, session: SessionDep, current: CurrentUser
+) -> None:
+    tree = await tree_service.get_tree(session, viewer_id=current.id, tree_id=tree_id)
+    await source_service.delete_source(session, actor=current, tree=tree, source_id=source_id)

backend/app/schemas/source.py

@@ -0,0 +1,61 @@
+import uuid
+from datetime import datetime
+
+from pydantic import BaseModel, ConfigDict
+
+from app.models.enums import CitationConfidence
+
+
+class SourceCreate(BaseModel):
+    title: str
+    author: str | None = None
+    source_type: str | None = None
+    repository: str | None = None
+    url: str | None = None
+    citation_text: str | None = None
+    publication_info: str | None = None
+    quality_note: str | None = None
+
+
+class SourceRead(BaseModel):
+    model_config = ConfigDict(from_attributes=True)
+
+    id: uuid.UUID
+    tree_id: uuid.UUID
+    title: str
+    author: str | None
+    source_type: str | None
+    repository: str | None
+    url: str | None
+    citation_text: str | None
+    publication_info: str | None
+    quality_note: str | None
+    created_at: datetime
+
+
+class CitationCreate(BaseModel):
+    source_id: uuid.UUID
+    # Exactly one target fact.
+    person_id: uuid.UUID | None = None
+    event_id: uuid.UUID | None = None
+    name_id: uuid.UUID | None = None
+    relationship_id: uuid.UUID | None = None
+    page: str | None = None
+    detail: str | None = None
+    confidence: CitationConfidence | None = None
+
+
+class CitationRead(BaseModel):
+    model_config = ConfigDict(from_attributes=True)
+
+    id: uuid.UUID
+    tree_id: uuid.UUID
+    source_id: uuid.UUID
+    person_id: uuid.UUID | None
+    event_id: uuid.UUID | None
+    name_id: uuid.UUID | None
+    relationship_id: uuid.UUID | None
+    page: str | None
+    detail: str | None
+    confidence: CitationConfidence | None
+    created_at: datetime

backend/app/services/citation_service.py

@@ -0,0 +1,141 @@
+"""Citation service. A citation links one Source to exactly one fact (person,
+event, name, or relationship) within a tree — the provenance spine."""
+
+import uuid
+from datetime import UTC, datetime
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.models.enums import CitationConfidence
+from app.models.event import Event
+from app.models.person import Name, Person
+from app.models.relationship import Relationship
+from app.models.source import Citation, Source
+from app.models.tree import Tree
+from app.models.user import User
+from app.services import privacy
+from app.services.audit import record_audit
+from app.services.exceptions import Conflict, Forbidden, NotFound
+
+# Citation target column -> model, for tenant/existence validation.
+_TARGET_MODELS = {
+    "person_id": Person,
+    "event_id": Event,
+    "name_id": Name,
+    "relationship_id": Relationship,
+}
+
+
+async def _in_tree(session: AsyncSession, model: type, id_: uuid.UUID, tree_id: uuid.UUID) -> bool:
+    row = (
+        await session.execute(
+            select(model.id).where(
+                model.id == id_, model.tree_id == tree_id, model.deleted_at.is_(None)
+            )
+        )
+    ).scalar_one_or_none()
+    return row is not None
+
+
+async def create_citation(
+    session: AsyncSession,
+    *,
+    actor: User,
+    tree: Tree,
+    source_id: uuid.UUID,
+    person_id: uuid.UUID | None = None,
+    event_id: uuid.UUID | None = None,
+    name_id: uuid.UUID | None = None,
+    relationship_id: uuid.UUID | None = None,
+    page: str | None = None,
+    detail: str | None = None,
+    confidence: CitationConfidence | None = None,
+) -> Citation:
+    if not await privacy.can_edit_tree(session, user_id=actor.id, tree=tree):
+        raise Forbidden("not an editor of this tree")
+
+    targets = {
+        "person_id": person_id,
+        "event_id": event_id,
+        "name_id": name_id,
+        "relationship_id": relationship_id,
+    }
+    set_targets = {k: v for k, v in targets.items() if v is not None}
+    if len(set_targets) != 1:
+        raise Conflict("a citation must reference exactly one fact")
+
+    if not await _in_tree(session, Source, source_id, tree.id):
+        raise NotFound("source not found in this tree")
+    (target_col, target_id), = set_targets.items()
+    if not await _in_tree(session, _TARGET_MODELS[target_col], target_id, tree.id):
+        raise NotFound("cited fact not found in this tree")
+
+    citation = Citation(
+        tree_id=tree.id,
+        source_id=source_id,
+        person_id=person_id,
+        event_id=event_id,
+        name_id=name_id,
+        relationship_id=relationship_id,
+        page=page,
+        detail=detail,
+        confidence=confidence,
+    )
+    session.add(citation)
+    await session.flush()
+    record_audit(
+        session,
+        action="create",
+        entity_type="Citation",
+        entity_id=citation.id,
+        tree_id=tree.id,
+        actor_user_id=actor.id,
+        after={"source_id": str(source_id), target_col: str(target_id)},
+    )
+    await session.commit()
+    await session.refresh(citation)
+    return citation
+
+
+async def list_citations(
+    session: AsyncSession, *, viewer_id: uuid.UUID, tree: Tree
+) -> list[Citation]:
+    """All citations in the tree — the UI maps them to facts to show 'sourced'
+    indicators in a single round-trip."""
+    if not await privacy.can_view_tree(session, user_id=viewer_id, tree=tree):
+        raise Forbidden("not permitted to view this tree")
+    stmt = (
+        select(Citation)
+        .where(Citation.tree_id == tree.id, Citation.deleted_at.is_(None))
+        .order_by(Citation.created_at)
+    )
+    return list((await session.execute(stmt)).scalars().all())
+
+
+async def delete_citation(
+    session: AsyncSession, *, actor: User, tree: Tree, citation_id: uuid.UUID
+) -> None:
+    if not await privacy.can_edit_tree(session, user_id=actor.id, tree=tree):
+        raise Forbidden("not an editor of this tree")
+    citation = (
+        await session.execute(
+            select(Citation).where(
+                Citation.id == citation_id,
+                Citation.tree_id == tree.id,
+                Citation.deleted_at.is_(None),
+            )
+        )
+    ).scalar_one_or_none()
+    if citation is None:
+        raise NotFound("citation not found")
+    citation.deleted_at = datetime.now(UTC)
+    record_audit(
+        session,
+        action="delete",
+        entity_type="Citation",
+        entity_id=citation.id,
+        tree_id=tree.id,
+        actor_user_id=actor.id,
+    )
+    await session.commit()

backend/app/services/source_service.py

@@ -0,0 +1,112 @@
+"""Source service. Sources are reusable, tree-scoped records of an origin.
+Writes require editor rights; reads go through the privacy engine."""
+
+import uuid
+from datetime import UTC, datetime
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.models.source import Source
+from app.models.tree import Tree
+from app.models.user import User
+from app.services import privacy
+from app.services.audit import record_audit
+from app.services.exceptions import Forbidden, NotFound
+
+
+async def create_source(
+    session: AsyncSession,
+    *,
+    actor: User,
+    tree: Tree,
+    title: str,
+    author: str | None = None,
+    source_type: str | None = None,
+    repository: str | None = None,
+    url: str | None = None,
+    citation_text: str | None = None,
+    publication_info: str | None = None,
+    quality_note: str | None = None,
+) -> Source:
+    if not await privacy.can_edit_tree(session, user_id=actor.id, tree=tree):
+        raise Forbidden("not an editor of this tree")
+    source = Source(
+        tree_id=tree.id,
+        title=title,
+        author=author,
+        source_type=source_type,
+        repository=repository,
+        url=url,
+        citation_text=citation_text,
+        publication_info=publication_info,
+        quality_note=quality_note,
+    )
+    session.add(source)
+    await session.flush()
+    record_audit(
+        session,
+        action="create",
+        entity_type="Source",
+        entity_id=source.id,
+        tree_id=tree.id,
+        actor_user_id=actor.id,
+        after={"title": title},
+    )
+    await session.commit()
+    await session.refresh(source)
+    return source
+
+
+async def list_sources(session: AsyncSession, *, viewer_id: uuid.UUID, tree: Tree) -> list[Source]:
+    if not await privacy.can_view_tree(session, user_id=viewer_id, tree=tree):
+        raise Forbidden("not permitted to view this tree")
+    stmt = (
+        select(Source)
+        .where(Source.tree_id == tree.id, Source.deleted_at.is_(None))
+        .order_by(Source.title)
+    )
+    return list((await session.execute(stmt)).scalars().all())
+
+
+async def get_source(
+    session: AsyncSession, *, viewer_id: uuid.UUID, tree: Tree, source_id: uuid.UUID
+) -> Source:
+    if not await privacy.can_view_tree(session, user_id=viewer_id, tree=tree):
+        raise Forbidden("not permitted to view this tree")
+    source = (
+        await session.execute(
+            select(Source).where(
+                Source.id == source_id, Source.tree_id == tree.id, Source.deleted_at.is_(None)
+            )
+        )
+    ).scalar_one_or_none()
+    if source is None:
+        raise NotFound("source not found")
+    return source
+
+
+async def delete_source(
+    session: AsyncSession, *, actor: User, tree: Tree, source_id: uuid.UUID
+) -> None:
+    if not await privacy.can_edit_tree(session, user_id=actor.id, tree=tree):
+        raise Forbidden("not an editor of this tree")
+    source = (
+        await session.execute(
+            select(Source).where(
+                Source.id == source_id, Source.tree_id == tree.id, Source.deleted_at.is_(None)
+            )
+        )
+    ).scalar_one_or_none()
+    if source is None:
+        raise NotFound("source not found")
+    source.deleted_at = datetime.now(UTC)
+    record_audit(
+        session,
+        action="delete",
+        entity_type="Source",
+        entity_id=source.id,
+        tree_id=tree.id,
+        actor_user_id=actor.id,
+    )
+    await session.commit()

backend/tests/test_sources.py

@@ -0,0 +1,96 @@
+"""Sources and citations (the provenance spine)."""
+
+import uuid
+
+from tests.conftest import auth, register
+
+
+async def _setup(client, email):
+    h = auth(await register(client, email))
+    tree_id = (await client.post("/api/v1/trees", json={"name": "S"}, headers=h)).json()["id"]
+    person = (
+        await client.post(
+            f"/api/v1/trees/{tree_id}/persons", json={"given": "Cy"}, headers=h
+        )
+    ).json()["id"]
+    event = (
+        await client.post(
+            f"/api/v1/trees/{tree_id}/events",
+            json={"event_type": "birth", "person_id": person},
+            headers=h,
+        )
+    ).json()["id"]
+    return h, tree_id, person, event
+
+
+async def test_source_and_citation_flow(client):
+    h, tree_id, person, event = await _setup(client, "src1@example.com")
+
+    src = await client.post(
+        f"/api/v1/trees/{tree_id}/sources",
+        json={"title": "1880 Census", "repository": "NARA"},
+        headers=h,
+    )
+    assert src.status_code == 201, src.text
+    source_id = src.json()["id"]
+
+    assert len((await client.get(f"/api/v1/trees/{tree_id}/sources", headers=h)).json()) == 1
+
+    # Cite the source on the birth event.
+    cite = await client.post(
+        f"/api/v1/trees/{tree_id}/citations",
+        json={"source_id": source_id, "event_id": event, "page": "p. 4"},
+        headers=h,
+    )
+    assert cite.status_code == 201, cite.text
+    citation_id = cite.json()["id"]
+
+    citations = (await client.get(f"/api/v1/trees/{tree_id}/citations", headers=h)).json()
+    assert len(citations) == 1
+    assert citations[0]["event_id"] == event
+    assert citations[0]["source_id"] == source_id
+
+    resp = await client.delete(f"/api/v1/trees/{tree_id}/citations/{citation_id}", headers=h)
+    assert resp.status_code == 204
+    assert len((await client.get(f"/api/v1/trees/{tree_id}/citations", headers=h)).json()) == 0
+
+
+async def test_citation_needs_exactly_one_target(client):
+    h, tree_id, person, event = await _setup(client, "src2@example.com")
+    source_id = (
+        await client.post(
+            f"/api/v1/trees/{tree_id}/sources", json={"title": "X"}, headers=h
+        )
+    ).json()["id"]
+
+    # No target.
+    r = await client.post(
+        f"/api/v1/trees/{tree_id}/citations", json={"source_id": source_id}, headers=h
+    )
+    assert r.status_code == 409
+    # Two targets.
+    r = await client.post(
+        f"/api/v1/trees/{tree_id}/citations",
+        json={"source_id": source_id, "person_id": person, "event_id": event},
+        headers=h,
+    )
+    assert r.status_code == 409
+
+
+async def test_citation_unknown_source_404(client):
+    h, tree_id, person, _ = await _setup(client, "src3@example.com")
+    r = await client.post(
+        f"/api/v1/trees/{tree_id}/citations",
+        json={"source_id": str(uuid.uuid4()), "person_id": person},
+        headers=h,
+    )
+    assert r.status_code == 404
+
+
+async def test_non_member_cannot_create_source(client):
+    h, tree_id, _, _ = await _setup(client, "src4@example.com")
+    other = auth(await register(client, "src-intruder@example.com"))
+    r = await client.post(
+        f"/api/v1/trees/{tree_id}/sources", json={"title": "nope"}, headers=other
+    )
+    assert r.status_code == 403