Phase 3 implementation. Coordinate system implemented. Initial text box tool implemented.

backend/app/api/v1/annotations.py

@@ -0,0 +1,91 @@
+from typing import Any
+from fastapi import APIRouter, Depends, HTTPException
+from sqlalchemy import select
+from sqlalchemy.orm import Session
+from datetime import datetime, timezone
+import json
+
+from app.db import get_db
+from app.models.document import Document
+from app.models.annotation_state import AnnotationState
+from app.auth.dependencies import get_current_user, verify_csrf
+from app.schemas.annotations import AnnotationStateResponse, AnnotationStateUpdateRequest, AnnotationStateUpdateResponse
+
+router = APIRouter(prefix="/documents", tags=["Annotations"])
+
+def _now_iso() -> str:
+    return datetime.now(timezone.utc).isoformat()
+
+@router.get("/{document_id}/annotations", response_model=AnnotationStateResponse)
+async def get_annotations(
+    document_id: str,
+    db: Session = Depends(get_db),
+    user_id: Any = Depends(get_current_user)
+):
+    doc = db.scalar(select(Document).where(Document.id == document_id, Document.deleted_at.is_(None)))
+    if not doc:
+        raise HTTPException(status_code=404, detail="Document not found")
+        
+    state = db.scalar(select(AnnotationState).where(AnnotationState.document_id == document_id))
+    
+    if not state:
+        return AnnotationStateResponse(data=[], updatedAt=datetime.now(timezone.utc))
+        
+    try:
+        data = json.loads(state.data)
+    except json.JSONDecodeError:
+        data = []
+        
+    return AnnotationStateResponse(
+        data=data,
+        updatedAt=datetime.fromisoformat(state.updated_at)
+    )
+
+@router.put("/{document_id}/annotations", response_model=AnnotationStateUpdateResponse, dependencies=[Depends(verify_csrf)])
+async def update_annotations(
+    document_id: str,
+    request: AnnotationStateUpdateRequest,
+    db: Session = Depends(get_db),
+    user_id: Any = Depends(get_current_user)
+):
+    doc = db.scalar(select(Document).where(Document.id == document_id, Document.deleted_at.is_(None)))
+    if not doc:
+        raise HTTPException(status_code=404, detail="Document not found")
+        
+    state = db.scalar(select(AnnotationState).where(AnnotationState.document_id == document_id))
+    
+    # Check for stale tab
+    if state and request.baseUpdatedAt:
+        current_updated_at = datetime.fromisoformat(state.updated_at).replace(tzinfo=timezone.utc)
+        request_updated_at = request.baseUpdatedAt.replace(tzinfo=timezone.utc)
+        # Allow a small grace period for timezone/parsing discrepancies
+        if abs((current_updated_at - request_updated_at).total_seconds()) > 1.0:
+            raise HTTPException(
+                status_code=409, 
+                detail=f"Conflict: annotations have been modified since {request.baseUpdatedAt}"
+            )
+            
+    now = _now_iso()
+    
+    import json
+    
+    # serialize request.data list of models to json string
+    data_json = json.dumps([a.model_dump(mode="json", by_alias=True) for a in request.data])
+
+    if not state:
+        state = AnnotationState(
+            document_id=document_id,
+            data=data_json,
+            updated_at=now
+        )
+        db.add(state)
+    else:
+        state.data = data_json
+        state.updated_at = now
+        
+    # Bump document updated_at
+    doc.updated_at = now
+        
+    db.commit()
+    
+    return AnnotationStateUpdateResponse(updatedAt=datetime.fromisoformat(now))