Add OCR, Background Removal, and PDF Editor features with tests

- Implemented OCR functionality using pytesseract for image and PDF text extraction.
- Added Background Removal service using rembg for image processing.
- Developed PDF Editor service for applying text annotations to PDF files.
- Created corresponding API routes for OCR, Background Removal, and PDF Editor.
- Added frontend components for OCR and Background Removal tools.
- Integrated feature flagging for new tools, ensuring they are disabled by default.
- Implemented comprehensive unit tests for OCR service, PDF editor, and background removal.
- Updated documentation to reflect new features and usage instructions.
- Added translations for new features in English, Arabic, and French.

backend/app/__init__.py

@@ -90,6 +90,9 @@ def create_app(config_name=None):
     from app.routes.flowchart import flowchart_bp
     from app.routes.v1.tools import v1_bp
     from app.routes.config import config_bp
+    from app.routes.ocr import ocr_bp
+    from app.routes.removebg import removebg_bp
+    from app.routes.pdf_editor import pdf_editor_bp
 
     app.register_blueprint(health_bp, url_prefix="/api")
     app.register_blueprint(auth_bp, url_prefix="/api/auth")
@@ -106,5 +109,8 @@ def create_app(config_name=None):
     app.register_blueprint(download_bp, url_prefix="/api/download")
     app.register_blueprint(v1_bp, url_prefix="/api/v1")
     app.register_blueprint(config_bp, url_prefix="/api/config")
+    app.register_blueprint(ocr_bp, url_prefix="/api/ocr")
+    app.register_blueprint(removebg_bp, url_prefix="/api/remove-bg")
+    app.register_blueprint(pdf_editor_bp, url_prefix="/api/pdf-editor")
 
     return app

backend/app/extensions.py

@@ -32,6 +32,9 @@ def init_celery(app):
         "app.tasks.video_tasks.*": {"queue": "video"},
         "app.tasks.pdf_tools_tasks.*": {"queue": "pdf_tools"},
         "app.tasks.flowchart_tasks.*": {"queue": "flowchart"},
+        "app.tasks.ocr_tasks.*": {"queue": "image"},
+        "app.tasks.removebg_tasks.*": {"queue": "image"},
+        "app.tasks.pdf_editor_tasks.*": {"queue": "pdf_tools"},
     }
 
     # Celery Beat — periodic tasks

backend/app/routes/ocr.py

@@ -0,0 +1,134 @@
+"""OCR routes — extract text from images and PDFs."""
+from flask import Blueprint, request, jsonify, current_app
+
+from app.extensions import limiter
+from app.services.policy_service import (
+    assert_quota_available,
+    build_task_tracking_kwargs,
+    PolicyError,
+    record_accepted_usage,
+    resolve_web_actor,
+    validate_actor_file,
+)
+from app.services.ocr_service import SUPPORTED_LANGUAGES
+from app.utils.file_validator import FileValidationError
+from app.utils.sanitizer import generate_safe_path
+from app.tasks.ocr_tasks import ocr_image_task, ocr_pdf_task
+
+ocr_bp = Blueprint("ocr", __name__)
+
+ALLOWED_IMAGE_TYPES = ["png", "jpg", "jpeg", "webp", "tiff", "bmp"]
+ALLOWED_OCR_TYPES = ALLOWED_IMAGE_TYPES + ["pdf"]
+
+
+def _check_feature_flag():
+    """Return an error response if FEATURE_EDITOR is disabled."""
+    if not current_app.config.get("FEATURE_EDITOR", False):
+        return jsonify({"error": "This feature is not enabled."}), 403
+    return None
+
+
+@ocr_bp.route("/image", methods=["POST"])
+@limiter.limit("10/minute")
+def ocr_image_route():
+    """Extract text from an image using OCR.
+
+    Accepts: multipart/form-data with:
+        - 'file': Image file
+        - 'lang' (optional): Language code — eng, ara, fra (default: eng)
+    Returns: JSON with task_id for polling
+    """
+    flag_err = _check_feature_flag()
+    if flag_err:
+        return flag_err
+
+    if "file" not in request.files:
+        return jsonify({"error": "No file provided."}), 400
+
+    file = request.files["file"]
+    lang = request.form.get("lang", "eng").lower()
+    if lang not in SUPPORTED_LANGUAGES:
+        lang = "eng"
+
+    actor = resolve_web_actor()
+    try:
+        assert_quota_available(actor)
+    except PolicyError as e:
+        return jsonify({"error": e.message}), e.status_code
+
+    try:
+        original_filename, ext = validate_actor_file(
+            file, allowed_types=ALLOWED_IMAGE_TYPES, actor=actor
+        )
+    except FileValidationError as e:
+        return jsonify({"error": e.message}), e.code
+
+    task_id, input_path = generate_safe_path(ext, folder_type="upload")
+    file.save(input_path)
+
+    task = ocr_image_task.delay(
+        input_path, task_id, original_filename, lang,
+        **build_task_tracking_kwargs(actor),
+    )
+    record_accepted_usage(actor, "ocr-image", task.id)
+
+    return jsonify({
+        "task_id": task.id,
+        "message": "OCR started. Poll /api/tasks/{task_id}/status for progress.",
+    }), 202
+
+
+@ocr_bp.route("/pdf", methods=["POST"])
+@limiter.limit("5/minute")
+def ocr_pdf_route():
+    """Extract text from a scanned PDF using OCR.
+
+    Accepts: multipart/form-data with:
+        - 'file': PDF file
+        - 'lang' (optional): Language code — eng, ara, fra (default: eng)
+    Returns: JSON with task_id for polling
+    """
+    flag_err = _check_feature_flag()
+    if flag_err:
+        return flag_err
+
+    if "file" not in request.files:
+        return jsonify({"error": "No file provided."}), 400
+
+    file = request.files["file"]
+    lang = request.form.get("lang", "eng").lower()
+    if lang not in SUPPORTED_LANGUAGES:
+        lang = "eng"
+
+    actor = resolve_web_actor()
+    try:
+        assert_quota_available(actor)
+    except PolicyError as e:
+        return jsonify({"error": e.message}), e.status_code
+
+    try:
+        original_filename, ext = validate_actor_file(
+            file, allowed_types=["pdf"], actor=actor
+        )
+    except FileValidationError as e:
+        return jsonify({"error": e.message}), e.code
+
+    task_id, input_path = generate_safe_path(ext, folder_type="upload")
+    file.save(input_path)
+
+    task = ocr_pdf_task.delay(
+        input_path, task_id, original_filename, lang,
+        **build_task_tracking_kwargs(actor),
+    )
+    record_accepted_usage(actor, "ocr-pdf", task.id)
+
+    return jsonify({
+        "task_id": task.id,
+        "message": "OCR started. Poll /api/tasks/{task_id}/status for progress.",
+    }), 202
+
+
+@ocr_bp.route("/languages", methods=["GET"])
+def ocr_languages_route():
+    """Return the list of supported OCR languages."""
+    return jsonify({"languages": SUPPORTED_LANGUAGES}), 200

backend/app/routes/pdf_editor.py

@@ -0,0 +1,80 @@
+"""PDF Editor route — apply text annotations to PDFs."""
+import json
+
+from flask import Blueprint, request, jsonify, current_app
+
+from app.extensions import limiter
+from app.services.policy_service import (
+    assert_quota_available,
+    build_task_tracking_kwargs,
+    PolicyError,
+    record_accepted_usage,
+    resolve_web_actor,
+    validate_actor_file,
+)
+from app.utils.file_validator import FileValidationError
+from app.utils.sanitizer import generate_safe_path
+from app.tasks.pdf_editor_tasks import edit_pdf_task
+
+pdf_editor_bp = Blueprint("pdf_editor", __name__)
+
+
+@pdf_editor_bp.route("/edit", methods=["POST"])
+@limiter.limit("10/minute")
+def edit_pdf_route():
+    """Apply text annotations to a PDF.
+
+    Accepts: multipart/form-data with:
+        - 'file': PDF file
+        - 'edits': JSON string — array of edit objects
+          Each edit: { type: "text", page: 1, x: 100, y: 200, content: "Hello", fontSize: 14, color: "#000000" }
+    Returns: JSON with task_id for polling
+    """
+    if not current_app.config.get("FEATURE_EDITOR", False):
+        return jsonify({"error": "This feature is not enabled."}), 403
+
+    if "file" not in request.files:
+        return jsonify({"error": "No file provided."}), 400
+
+    file = request.files["file"]
+    edits_raw = request.form.get("edits", "[]")
+
+    try:
+        edits = json.loads(edits_raw)
+        if not isinstance(edits, list):
+            return jsonify({"error": "Edits must be a JSON array."}), 400
+    except (json.JSONDecodeError, TypeError):
+        return jsonify({"error": "Invalid JSON in 'edits' field."}), 400
+
+    if not edits:
+        return jsonify({"error": "At least one edit is required."}), 400
+
+    if len(edits) > 500:
+        return jsonify({"error": "Maximum 500 edits allowed."}), 400
+
+    actor = resolve_web_actor()
+    try:
+        assert_quota_available(actor)
+    except PolicyError as e:
+        return jsonify({"error": e.message}), e.status_code
+
+    try:
+        original_filename, ext = validate_actor_file(
+            file, allowed_types=["pdf"], actor=actor
+        )
+    except FileValidationError as e:
+        return jsonify({"error": e.message}), e.code
+
+    task_id, input_path = generate_safe_path(ext, folder_type="upload")
+    file.save(input_path)
+
+    task = edit_pdf_task.delay(
+        input_path, task_id, original_filename, edits,
+        **build_task_tracking_kwargs(actor),
+    )
+    record_accepted_usage(actor, "pdf-edit", task.id)
+
+    return jsonify({
+        "task_id": task.id,
+        "message": "PDF editing started. Poll /api/tasks/{task_id}/status for progress.",
+    }), 202

backend/app/routes/removebg.py

@@ -0,0 +1,64 @@
+"""Background removal route."""
+from flask import Blueprint, request, jsonify, current_app
+
+from app.extensions import limiter
+from app.services.policy_service import (
+    assert_quota_available,
+    build_task_tracking_kwargs,
+    PolicyError,
+    record_accepted_usage,
+    resolve_web_actor,
+    validate_actor_file,
+)
+from app.utils.file_validator import FileValidationError
+from app.utils.sanitizer import generate_safe_path
+from app.tasks.removebg_tasks import remove_bg_task
+
+removebg_bp = Blueprint("removebg", __name__)
+
+ALLOWED_IMAGE_TYPES = ["png", "jpg", "jpeg", "webp"]
+
+
+@removebg_bp.route("", methods=["POST"])
+@limiter.limit("5/minute")
+def remove_bg_route():
+    """Remove the background from an image.
+
+    Accepts: multipart/form-data with:
+        - 'file': Image file (PNG, JPG, JPEG, WebP)
+    Returns: JSON with task_id for polling
+    """
+    if not current_app.config.get("FEATURE_EDITOR", False):
+        return jsonify({"error": "This feature is not enabled."}), 403
+
+    if "file" not in request.files:
+        return jsonify({"error": "No file provided."}), 400
+
+    file = request.files["file"]
+
+    actor = resolve_web_actor()
+    try:
+        assert_quota_available(actor)
+    except PolicyError as e:
+        return jsonify({"error": e.message}), e.status_code
+
+    try:
+        original_filename, ext = validate_actor_file(
+            file, allowed_types=ALLOWED_IMAGE_TYPES, actor=actor
+        )
+    except FileValidationError as e:
+        return jsonify({"error": e.message}), e.code
+
+    task_id, input_path = generate_safe_path(ext, folder_type="upload")
+    file.save(input_path)
+
+    task = remove_bg_task.delay(
+        input_path, task_id, original_filename,
+        **build_task_tracking_kwargs(actor),
+    )
+    record_accepted_usage(actor, "remove-bg", task.id)
+
+    return jsonify({
+        "task_id": task.id,
+        "message": "Background removal started. Poll /api/tasks/{task_id}/status for progress.",
+    }), 202

backend/app/services/ocr_service.py

@@ -0,0 +1,121 @@
+"""OCR service — extract text from images and PDFs using Tesseract."""
+import logging
+import os
+import subprocess
+import tempfile
+
+from PIL import Image
+
+logger = logging.getLogger(__name__)
+
+
+class OCRError(Exception):
+    """Custom exception for OCR failures."""
+    pass
+
+
+# Tesseract language codes
+SUPPORTED_LANGUAGES = {
+    "eng": "English",
+    "ara": "Arabic",
+    "fra": "French",
+}
+
+DEFAULT_LANG = "eng"
+
+
+def _get_tesseract_cmd() -> str:
+    """Return the tesseract binary path."""
+    return os.getenv("TESSERACT_CMD", "tesseract")
+
+
+def ocr_image(input_path: str, lang: str = DEFAULT_LANG) -> dict:
+    """Extract text from an image file using Tesseract.
+
+    Args:
+        input_path: Path to the input image.
+        lang: Tesseract language code (e.g. "eng", "ara", "fra").
+
+    Returns:
+        dict with ``text``, ``lang``, ``char_count``.
+
+    Raises:
+        OCRError: If the OCR operation fails.
+    """
+    if lang not in SUPPORTED_LANGUAGES:
+        lang = DEFAULT_LANG
+
+    try:
+        import pytesseract
+
+        pytesseract.pytesseract.tesseract_cmd = _get_tesseract_cmd()
+
+        with Image.open(input_path) as img:
+            # Convert to RGB if needed (tesseract works best with RGB)
+            if img.mode not in ("RGB", "L"):
+                img = img.convert("RGB")
+            text = pytesseract.image_to_string(img, lang=lang)
+
+        text = text.strip()
+        return {
+            "text": text,
+            "lang": lang,
+            "char_count": len(text),
+        }
+    except ImportError:
+        raise OCRError("pytesseract is not installed.")
+    except Exception as e:
+        raise OCRError(f"OCR failed: {str(e)}")
+
+
+def ocr_pdf(input_path: str, output_path: str, lang: str = DEFAULT_LANG) -> dict:
+    """Extract text from a scanned PDF by converting pages to images first.
+
+    Args:
+        input_path: Path to the input PDF.
+        output_path: Path for the output text file.
+        lang: Tesseract language code.
+
+    Returns:
+        dict with ``text``, ``page_count``, ``char_count``.
+
+    Raises:
+        OCRError: If the OCR operation fails.
+    """
+    if lang not in SUPPORTED_LANGUAGES:
+        lang = DEFAULT_LANG
+
+    try:
+        from pdf2image import convert_from_path
+        import pytesseract
+
+        pytesseract.pytesseract.tesseract_cmd = _get_tesseract_cmd()
+
+        images = convert_from_path(input_path, dpi=300)
+        if not images:
+            raise OCRError("Could not convert PDF to images — file may be empty.")
+
+        all_text = []
+        for i, img in enumerate(images, 1):
+            if img.mode not in ("RGB", "L"):
+                img = img.convert("RGB")
+            page_text = pytesseract.image_to_string(img, lang=lang)
+            all_text.append(f"--- Page {i} ---\n{page_text.strip()}")
+
+        full_text = "\n\n".join(all_text)
+
+        os.makedirs(os.path.dirname(output_path), exist_ok=True)
+        with open(output_path, "w", encoding="utf-8") as f:
+            f.write(full_text)
+
+        return {
+            "text": full_text,
+            "page_count": len(images),
+            "char_count": len(full_text),
+        }
+    except ImportError as e:
+        raise OCRError(f"Missing dependency: {e}")
+    except OCRError:
+        raise
+    except Exception as e:
+        raise OCRError(f"PDF OCR failed: {str(e)}")

backend/app/services/pdf_editor_service.py

@@ -0,0 +1,120 @@
+"""PDF Editor service — add text annotations and simple edits to PDFs."""
+import io
+import logging
+import os
+
+logger = logging.getLogger(__name__)
+
+
+class PDFEditorError(Exception):
+    """Custom exception for PDF editor failures."""
+    pass
+
+
+def apply_pdf_edits(input_path: str, output_path: str, edits: list[dict]) -> dict:
+    """Apply a list of edits (text annotations) to an existing PDF.
+
+    Each edit dict can contain:
+        - type: "text"
+        - page: 1-based page number
+        - x, y: position in points from bottom-left
+        - content: text string to place
+        - fontSize: optional, default 12
+        - color: optional hex e.g. "#000000"
+
+    Args:
+        input_path: Path to the source PDF.
+        output_path: Path for the edited PDF.
+        edits: List of edit operation dicts.
+
+    Returns:
+        dict with ``page_count``, ``edits_applied``, ``output_size``.
+
+    Raises:
+        PDFEditorError: If the edit fails.
+    """
+    if not edits:
+        raise PDFEditorError("No edits provided.")
+
+    os.makedirs(os.path.dirname(output_path), exist_ok=True)
+
+    try:
+        from PyPDF2 import PdfReader, PdfWriter
+        from reportlab.pdfgen import canvas
+        from reportlab.lib.pagesizes import letter
+        from reportlab.lib.colors import HexColor
+
+        reader = PdfReader(input_path)
+        writer = PdfWriter()
+        page_count = len(reader.pages)
+
+        if page_count == 0:
+            raise PDFEditorError("PDF has no pages.")
+
+        # Group edits by page
+        edits_by_page: dict[int, list[dict]] = {}
+        for edit in edits:
+            page_num = int(edit.get("page", 1))
+            if page_num < 1 or page_num > page_count:
+                continue
+            edits_by_page.setdefault(page_num, []).append(edit)
+
+        edits_applied = 0
+
+        for page_idx in range(page_count):
+            page = reader.pages[page_idx]
+            page_num = page_idx + 1
+            page_edits = edits_by_page.get(page_num, [])
+
+            if page_edits:
+                # Get page dimensions
+                media_box = page.mediabox
+                page_width = float(media_box.width)
+                page_height = float(media_box.height)
+
+                # Create overlay with annotations
+                packet = io.BytesIO()
+                c = canvas.Canvas(packet, pagesize=(page_width, page_height))
+
+                for edit in page_edits:
+                    edit_type = edit.get("type", "text")
+                    if edit_type == "text":
+                        x = float(edit.get("x", 72))
+                        y = float(edit.get("y", 72))
+                        content = str(edit.get("content", ""))
+                        font_size = int(edit.get("fontSize", 12))
+                        color = str(edit.get("color", "#000000"))
+
+                        try:
+                            c.setFillColor(HexColor(color))
+                        except Exception:
+                            c.setFillColor(HexColor("#000000"))
+
+                        c.setFont("Helvetica", font_size)
+                        c.drawString(x, y, content)
+                        edits_applied += 1
+
+                c.save()
+                packet.seek(0)
+
+                overlay_reader = PdfReader(packet)
+                if len(overlay_reader.pages) > 0:
+                    page.merge_page(overlay_reader.pages[0])
+
+            writer.add_page(page)
+
+        with open(output_path, "wb") as f:
+            writer.write(f)
+
+        output_size = os.path.getsize(output_path)
+
+        return {
+            "page_count": page_count,
+            "edits_applied": edits_applied,
+            "output_size": output_size,
+        }
+
+    except PDFEditorError:
+        raise
+    except Exception as e:
+        raise PDFEditorError(f"PDF editing failed: {str(e)}")

backend/app/services/removebg_service.py

@@ -0,0 +1,60 @@
+"""Background removal service using rembg."""
+import logging
+import os
+
+from PIL import Image
+
+logger = logging.getLogger(__name__)
+
+
+class RemoveBGError(Exception):
+    """Custom exception for background removal failures."""
+    pass
+
+
+def remove_background(input_path: str, output_path: str) -> dict:
+    """Remove the background from an image.
+
+    Args:
+        input_path: Path to the input image.
+        output_path: Path for the output PNG (always PNG — transparency).
+
+    Returns:
+        dict with ``original_size``, ``output_size``, ``width``, ``height``.
+
+    Raises:
+        RemoveBGError: If the operation fails.
+    """
+    os.makedirs(os.path.dirname(output_path), exist_ok=True)
+
+    try:
+        from rembg import remove as rembg_remove
+
+        with Image.open(input_path) as img:
+            if img.mode != "RGBA":
+                img = img.convert("RGBA")
+            width, height = img.size
+            original_size = os.path.getsize(input_path)
+
+            result = rembg_remove(img)
+            result.save(output_path, format="PNG", optimize=True)
+
+        output_size = os.path.getsize(output_path)
+
+        logger.info(
+            "Background removed: %s → %s (%d → %d bytes)",
+            input_path, output_path, original_size, output_size,
+        )
+
+        return {
+            "original_size": original_size,
+            "output_size": output_size,
+            "width": width,
+            "height": height,
+        }
+    except ImportError:
+        raise RemoveBGError("rembg is not installed.")
+    except (IOError, OSError) as e:
+        raise RemoveBGError(f"Background removal failed: {str(e)}")
+    except Exception as e:
+        raise RemoveBGError(f"Background removal failed: {str(e)}")

backend/app/tasks/ocr_tasks.py

@@ -0,0 +1,159 @@
+"""Celery tasks for OCR processing."""
+import os
+import logging
+
+from flask import current_app
+
+from app.extensions import celery
+from app.services.ocr_service import ocr_image, ocr_pdf, OCRError
+from app.services.storage_service import storage
+from app.services.task_tracking_service import finalize_task_tracking
+from app.utils.sanitizer import cleanup_task_files
+
+logger = logging.getLogger(__name__)
+
+
+def _cleanup(task_id: str):
+    cleanup_task_files(task_id, keep_outputs=not storage.use_s3)
+
+
+def _get_output_dir(task_id: str) -> str:
+    output_dir = os.path.join(current_app.config["OUTPUT_FOLDER"], task_id)
+    os.makedirs(output_dir, exist_ok=True)
+    return output_dir
+
+
+def _finalize_task(
+    task_id, user_id, tool, original_filename, result,
+    usage_source, api_key_id, celery_task_id,
+):
+    finalize_task_tracking(
+        user_id=user_id, tool=tool, original_filename=original_filename,
+        result=result, usage_source=usage_source,
+        api_key_id=api_key_id, celery_task_id=celery_task_id,
+    )
+    _cleanup(task_id)
+    return result
+
+
+@celery.task(bind=True, name="app.tasks.ocr_tasks.ocr_image_task")
+def ocr_image_task(
+    self,
+    input_path: str,
+    task_id: str,
+    original_filename: str,
+    lang: str = "eng",
+    user_id: int | None = None,
+    usage_source: str = "web",
+    api_key_id: int | None = None,
+):
+    """Async task: Extract text from an image via OCR."""
+    output_dir = _get_output_dir(task_id)
+    output_path = os.path.join(output_dir, f"{task_id}.txt")
+
+    try:
+        self.update_state(state="PROCESSING", meta={"step": "Running OCR on image..."})
+
+        stats = ocr_image(input_path, lang=lang)
+
+        # Write text to file for download
+        with open(output_path, "w", encoding="utf-8") as f:
+            f.write(stats["text"])
+
+        self.update_state(state="PROCESSING", meta={"step": "Uploading result..."})
+        s3_key = storage.upload_file(output_path, task_id, folder="outputs")
+
+        name_without_ext = os.path.splitext(original_filename)[0]
+        download_name = f"{name_without_ext}_ocr.txt"
+
+        download_url = storage.generate_presigned_url(s3_key, original_filename=download_name)
+
+        result = {
+            "status": "completed",
+            "download_url": download_url,
+            "filename": download_name,
+            "text": stats["text"][:5000],  # preview (first 5k chars)
+            "char_count": stats["char_count"],
+            "lang": stats["lang"],
+        }
+
+        logger.info("Task %s: OCR image completed (%d chars)", task_id, stats["char_count"])
+        return _finalize_task(
+            task_id, user_id, "ocr-image", original_filename,
+            result, usage_source, api_key_id, self.request.id,
+        )
+
+    except OCRError as e:
+        logger.error("Task %s: OCR error — %s", task_id, e)
+        return _finalize_task(
+            task_id, user_id, "ocr-image", original_filename,
+            {"status": "failed", "error": str(e)},
+            usage_source, api_key_id, self.request.id,
+        )
+    except Exception as e:
+        logger.error("Task %s: Unexpected error — %s", task_id, e)
+        return _finalize_task(
+            task_id, user_id, "ocr-image", original_filename,
+            {"status": "failed", "error": "An unexpected error occurred."},
+            usage_source, api_key_id, self.request.id,
+        )
+
+
+@celery.task(bind=True, name="app.tasks.ocr_tasks.ocr_pdf_task")
+def ocr_pdf_task(
+    self,
+    input_path: str,
+    task_id: str,
+    original_filename: str,
+    lang: str = "eng",
+    user_id: int | None = None,
+    usage_source: str = "web",
+    api_key_id: int | None = None,
+):
+    """Async task: Extract text from a scanned PDF via OCR."""
+    output_dir = _get_output_dir(task_id)
+    output_path = os.path.join(output_dir, f"{task_id}.txt")
+
+    try:
+        self.update_state(state="PROCESSING", meta={"step": "Converting PDF pages & running OCR..."})
+
+        stats = ocr_pdf(input_path, output_path, lang=lang)
+
+        self.update_state(state="PROCESSING", meta={"step": "Uploading result..."})
+        s3_key = storage.upload_file(output_path, task_id, folder="outputs")
+
+        name_without_ext = os.path.splitext(original_filename)[0]
+        download_name = f"{name_without_ext}_ocr.txt"
+
+        download_url = storage.generate_presigned_url(s3_key, original_filename=download_name)
+
+        result = {
+            "status": "completed",
+            "download_url": download_url,
+            "filename": download_name,
+            "text": stats["text"][:5000],
+            "page_count": stats["page_count"],
+            "char_count": stats["char_count"],
+            "lang": lang,
+        }
+
+        logger.info("Task %s: OCR PDF completed (%d pages, %d chars)", task_id, stats["page_count"], stats["char_count"])
+        return _finalize_task(
+            task_id, user_id, "ocr-pdf", original_filename,
+            result, usage_source, api_key_id, self.request.id,
+        )
+
+    except OCRError as e:
+        logger.error("Task %s: OCR error — %s", task_id, e)
+        return _finalize_task(
+            task_id, user_id, "ocr-pdf", original_filename,
+            {"status": "failed", "error": str(e)},
+            usage_source, api_key_id, self.request.id,
+        )
+    except Exception as e:
+        logger.error("Task %s: Unexpected error — %s", task_id, e)
+        return _finalize_task(
+            task_id, user_id, "ocr-pdf", original_filename,
+            {"status": "failed", "error": "An unexpected error occurred."},
+            usage_source, api_key_id, self.request.id,
+        )

backend/app/tasks/pdf_editor_tasks.py

@@ -0,0 +1,95 @@
+"""Celery tasks for PDF editing."""
+import os
+import logging
+
+from flask import current_app
+
+from app.extensions import celery
+from app.services.pdf_editor_service import apply_pdf_edits, PDFEditorError
+from app.services.storage_service import storage
+from app.services.task_tracking_service import finalize_task_tracking
+from app.utils.sanitizer import cleanup_task_files
+
+logger = logging.getLogger(__name__)
+
+
+def _cleanup(task_id: str):
+    cleanup_task_files(task_id, keep_outputs=not storage.use_s3)
+
+
+def _get_output_dir(task_id: str) -> str:
+    output_dir = os.path.join(current_app.config["OUTPUT_FOLDER"], task_id)
+    os.makedirs(output_dir, exist_ok=True)
+    return output_dir
+
+
+def _finalize_task(
+    task_id, user_id, tool, original_filename, result,
+    usage_source, api_key_id, celery_task_id,
+):
+    finalize_task_tracking(
+        user_id=user_id, tool=tool, original_filename=original_filename,
+        result=result, usage_source=usage_source,
+        api_key_id=api_key_id, celery_task_id=celery_task_id,
+    )
+    _cleanup(task_id)
+    return result
+
+
+@celery.task(bind=True, name="app.tasks.pdf_editor_tasks.edit_pdf_task")
+def edit_pdf_task(
+    self,
+    input_path: str,
+    task_id: str,
+    original_filename: str,
+    edits: list[dict],
+    user_id: int | None = None,
+    usage_source: str = "web",
+    api_key_id: int | None = None,
+):
+    """Async task: Apply text annotations to a PDF."""
+    output_dir = _get_output_dir(task_id)
+    output_path = os.path.join(output_dir, f"{task_id}.pdf")
+
+    try:
+        self.update_state(state="PROCESSING", meta={"step": "Applying edits to PDF..."})
+
+        stats = apply_pdf_edits(input_path, output_path, edits)
+
+        self.update_state(state="PROCESSING", meta={"step": "Uploading result..."})
+        s3_key = storage.upload_file(output_path, task_id, folder="outputs")
+
+        name_without_ext = os.path.splitext(original_filename)[0]
+        download_name = f"{name_without_ext}_edited.pdf"
+
+        download_url = storage.generate_presigned_url(s3_key, original_filename=download_name)
+
+        result = {
+            "status": "completed",
+            "download_url": download_url,
+            "filename": download_name,
+            "page_count": stats["page_count"],
+            "edits_applied": stats["edits_applied"],
+            "output_size": stats["output_size"],
+        }
+
+        logger.info("Task %s: PDF edit completed (%d edits)", task_id, stats["edits_applied"])
+        return _finalize_task(
+            task_id, user_id, "pdf-edit", original_filename,
+            result, usage_source, api_key_id, self.request.id,
+        )
+
+    except PDFEditorError as e:
+        logger.error("Task %s: PDF edit error — %s", task_id, e)
+        return _finalize_task(
+            task_id, user_id, "pdf-edit", original_filename,
+            {"status": "failed", "error": str(e)},
+            usage_source, api_key_id, self.request.id,
+        )
+    except Exception as e:
+        logger.error("Task %s: Unexpected error — %s", task_id, e)
+        return _finalize_task(
+            task_id, user_id, "pdf-edit", original_filename,
+            {"status": "failed", "error": "An unexpected error occurred."},
+            usage_source, api_key_id, self.request.id,
+        )

backend/app/tasks/removebg_tasks.py

@@ -0,0 +1,95 @@
+"""Celery tasks for background removal."""
+import os
+import logging
+
+from flask import current_app
+
+from app.extensions import celery
+from app.services.removebg_service import remove_background, RemoveBGError
+from app.services.storage_service import storage
+from app.services.task_tracking_service import finalize_task_tracking
+from app.utils.sanitizer import cleanup_task_files
+
+logger = logging.getLogger(__name__)
+
+
+def _cleanup(task_id: str):
+    cleanup_task_files(task_id, keep_outputs=not storage.use_s3)
+
+
+def _get_output_dir(task_id: str) -> str:
+    output_dir = os.path.join(current_app.config["OUTPUT_FOLDER"], task_id)
+    os.makedirs(output_dir, exist_ok=True)
+    return output_dir
+
+
+def _finalize_task(
+    task_id, user_id, tool, original_filename, result,
+    usage_source, api_key_id, celery_task_id,
+):
+    finalize_task_tracking(
+        user_id=user_id, tool=tool, original_filename=original_filename,
+        result=result, usage_source=usage_source,
+        api_key_id=api_key_id, celery_task_id=celery_task_id,
+    )
+    _cleanup(task_id)
+    return result
+
+
+@celery.task(bind=True, name="app.tasks.removebg_tasks.remove_bg_task")
+def remove_bg_task(
+    self,
+    input_path: str,
+    task_id: str,
+    original_filename: str,
+    user_id: int | None = None,
+    usage_source: str = "web",
+    api_key_id: int | None = None,
+):
+    """Async task: Remove background from an image."""
+    output_dir = _get_output_dir(task_id)
+    output_path = os.path.join(output_dir, f"{task_id}.png")
+
+    try:
+        self.update_state(state="PROCESSING", meta={"step": "Removing background..."})
+
+        stats = remove_background(input_path, output_path)
+
+        self.update_state(state="PROCESSING", meta={"step": "Uploading result..."})
+        s3_key = storage.upload_file(output_path, task_id, folder="outputs")
+
+        name_without_ext = os.path.splitext(original_filename)[0]
+        download_name = f"{name_without_ext}_nobg.png"
+
+        download_url = storage.generate_presigned_url(s3_key, original_filename=download_name)
+
+        result = {
+            "status": "completed",
+            "download_url": download_url,
+            "filename": download_name,
+            "original_size": stats["original_size"],
+            "output_size": stats["output_size"],
+            "width": stats["width"],
+            "height": stats["height"],
+        }
+
+        logger.info("Task %s: Background removal completed", task_id)
+        return _finalize_task(
+            task_id, user_id, "remove-bg", original_filename,
+            result, usage_source, api_key_id, self.request.id,
+        )
+
+    except RemoveBGError as e:
+        logger.error("Task %s: RemoveBG error — %s", task_id, e)
+        return _finalize_task(
+            task_id, user_id, "remove-bg", original_filename,
+            {"status": "failed", "error": str(e)},
+            usage_source, api_key_id, self.request.id,
+        )
+    except Exception as e:
+        logger.error("Task %s: Unexpected error — %s", task_id, e)
+        return _finalize_task(
+            task_id, user_id, "remove-bg", original_filename,
+            {"status": "failed", "error": "An unexpected error occurred."},
+            usage_source, api_key_id, self.request.id,
+        )