from decimal import Decimal, InvalidOperation from rest_framework.response import Response from django.shortcuts import get_object_or_404, render,redirect from django.views import View from codesofy.custom_config import get_local_date, set_user_profile,convert_to_decimal,get_privilleges,get_standard_text_input,get_unique_text,is_authorized,set_menu_items,get_global_master_details from codesofy.master_details import PerPageSelector, ProductType from constants.general_const import ActiveStatus from core.utils import get_api_message from cropmanagement.models import Crop from mydevicemanagement import apps from products.models import Product from scalemanagement.serializers import ScaleCropMappingLiteSerializer from .models import Scale, ScaleCropMapping from usermanagement.models import UserProfile from utils.product_utils import dict_diff, product_to_dict from rest_framework import serializers from django.contrib import messages from django.db import transaction, IntegrityError from django.db.models import RestrictedError from django.views.decorators.cache import cache_control from django.utils.decorators import method_decorator import math from django.core.paginator import Paginator from django.http import Http404, HttpResponse, HttpResponseBadRequest, JsonResponse import json from django.db.models import Max from PIL import Image from io import BytesIO from django.utils.timezone import now from django.contrib import messages from django.db import transaction, IntegrityError, models from rest_framework import viewsets, permissions, status from django.db.models.deletion import RestrictedError from django.db.models import ProtectedError from rest_framework import viewsets, permissions from django.db.models import Q from rest_framework.views import APIView from rest_framework.response import Response from rest_framework.permissions import AllowAny from rest_framework import status from django.core.paginator import Paginator from django.db.models import RestrictedError from django.core.exceptions import ObjectDoesNotExist menu_item = "scale_registry" def set_sub_menu_item(sub_menu_item,context): context = set_menu_items(menu_item,sub_menu_item,context) return context def get_local_master_details(): context = get_global_master_details() return context def _get_customer(request): cust = getattr(request.user, "customer", None) if not cust: # Should not happen because HasCustomerProfile is applied, but keep safe raise Http404("Not found.") return cust class HasCustomerProfile(permissions.BasePermission): """Allow only authenticated users that have a related .customer object.""" def has_permission(self, request, view): return bool(request.user and request.user.is_authenticated and getattr(request.user, "customer", None)) class IsCustomerOwner(permissions.BasePermission): """ Object-level permission helper for APIViews. Use it by calling `self.check_object_permissions(request, obj)` in your view after loading `obj`. Expects obj.customer_device.customer_id to match the current user's customer.id. """ def has_object_permission(self, request, view, obj): cust = getattr(request.user, "customer", None) if not cust: return False device = getattr(obj, "customer_device", None) if not device: return False return getattr(device, "customer_id", None) == cust.id def get_local_master_details_for_add_update_scalecropmapping(): context = get_local_master_details() scale_list = Scale.objects.all() crop_list = Crop.objects.all() mapping_status = ActiveStatus.to_list() context["mapping_status_list"] = mapping_status context['scale_list'] = scale_list context['crop_list'] = crop_list return context def get_local_master_details_for_scalecropmapping_details(): context = get_local_master_details() scale_list = Scale.objects.all() mapping_status = ActiveStatus.to_list_for_reports() context["mapping_status_list"] = mapping_status context['scale_list'] = scale_list return context def find_reverse_dependencies(instance, sample_per_relation: int = 3): """ Return a dict of {relation_label: [pk,...]} for reverse related objects that currently exist referencing `instance`. Uses model metadata, so you don't have to hardcode table names. """ blockers = {} # Walk all reverse relations declared on the model for rel in instance._meta.related_objects: # rel is a ManyToOneRel / ManyToManyRel / OneToOneRel (reverse side) accessor = rel.get_accessor_name() # e.g. "order_items", "results" manager = getattr(instance, accessor, None) if manager is None: continue # For O2O, manager is a single object accessor; handle safely try: if rel.one_to_one: try: obj = manager # If it exists, accessing .pk will not raise _ = obj.pk blockers[rel.related_model._meta.label] = [obj.pk] except rel.related_model.DoesNotExist: pass continue except AttributeError: # Older Django or unusual relation – skip continue # For reverse FK/M2M, manager is a RelatedManager try: qs = manager.all() except Exception: continue # Only flag if there are rows if qs.exists(): # Sample a few PKs for the message blockers[rel.related_model._meta.label] = list(qs.values_list("pk", flat=True)[:sample_per_relation]) return blockers @method_decorator(cache_control(no_cache=True, must_revalidate=True, no_store=True), name='dispatch') class AddScaleView(View): this_feature = "add_scale" sub_menu_item = "scale_list" def get(self, request): # This page is just the form; but your form+list live together. # Redirect to the list so the template gets full context. return redirect('scale-list') def post(self, request): user_profile = set_user_profile(request, {}) if user_profile is None: return redirect('login') if not is_authorized(user_profile, self.this_feature): return redirect('unauthorized-access') description = (request.POST.get('description') or '').strip() scale_id = (request.POST.get('scale_id') or '').strip() # Basic server-side validation if not scale_id or not description : messages.error(request, "Scale ID $Description are required.") return redirect('scale-list') try: with transaction.atomic(): # Normalize case consistently for both check and save scale_id = scale_id if Scale.objects.filter(scale_id__iexact=scale_id).exists(): messages.error(request, "Unique Scale ID already exists.") return redirect('scale-list') Scale.objects.create( description=description, scale_id=scale_id, created_by=user_profile, updated_by=user_profile, created_At = now(), updated_At = now(), ) messages.success(request, "New scale was created successfully.") return redirect('scale-list') except Exception as exp: messages.error(request, f"Unexpected Error: {exp}") messages.error(request, "Error occurred in atomic operation. Contact the administrator.") return redirect('scale-list') @method_decorator(cache_control(no_cache=True, must_revalidate=True,no_store=True), name='dispatch') class ViewScaleView(View): this_feature = "view_scale" sub_menu_item = "scale_list" def get(self, request,id): context = get_local_master_details() user_profile = set_user_profile(request,context) if user_profile==None: return redirect('login') get_privilleges(user_profile,context) if not is_authorized(user_profile,self.this_feature): return redirect('unauthorized-access') set_sub_menu_item(self.sub_menu_item,context) try: with transaction.atomic(): if Scale.objects.filter(pk=id).exists(): scale = Scale.objects.get(pk=id) context["scale"] = scale return render(request, 'scale.html', context) else: return redirect ('scale') except Exception or IntegrityError as exp: print (exp) messages.error( request, "Error Occured in atomic operation. Contact the System Administrator") return redirect ('scale') @method_decorator(cache_control(no_cache=True, must_revalidate=True,no_store=True), name='dispatch') class ScaleListView(View): this_feature = "scale_list" sub_menu_item = "scale_list" def get(self, request): context = get_local_master_details() user_profile = set_user_profile(request,context) if user_profile==None: return redirect('login') get_privilleges(user_profile,context) if not is_authorized(user_profile,self.this_feature): return redirect('unauthorized-access') set_sub_menu_item(self.sub_menu_item,context) per_page_count = request.GET.get('per_page_count') page_number = request.GET.get('page_number') start_index = request.GET.get('start_index') if not page_number: page_number = 1 if not per_page_count: per_page_count = 10 if start_index: page_number = math.ceil(int(start_index)/int(per_page_count)) context["default_per_page_count"] = per_page_count scale_list = Scale.objects.all().order_by('-id') if len(scale_list)>0: context["has_entries"] = True else: context["has_entries"] = False paginator = Paginator(scale_list,per_page_count) page = Paginator.get_page(paginator,page_number) page_list = list(paginator.get_elided_page_range(page_number, on_each_side=1)) context["page"] = page context["page_list"] = page_list return render(request, 'scale.html', context) @method_decorator(cache_control(no_cache=True, must_revalidate=True, no_store=True), name='dispatch') class UpdateScaleView(View): this_feature = "update_scale" sub_menu_item = "scale_list" # Handles: GET /update-scale/ def get(self, request, id): context = {} user_profile = set_user_profile(request, context) if user_profile is None: return redirect('login') get_privilleges(user_profile, context) if not is_authorized(user_profile, self.this_feature): return redirect('unauthorized-access') set_sub_menu_item(self.sub_menu_item, context) lang = get_object_or_404(Scale, pk=id) context["scale"] = lang context["old_input_field_values"] = {} return render(request, "update-scale.html", context) # Handles: POST /update-scale (id is taken from form) def post(self, request): context = {} user_profile = set_user_profile(request, context) if user_profile is None: return redirect('login') get_privilleges(user_profile, context) if not is_authorized(user_profile, self.this_feature): return redirect('unauthorized-access') set_sub_menu_item(self.sub_menu_item, context) try: id_ = int(request.POST.get("id") or 0) except ValueError: messages.error(request, "Invalid scale id.") return redirect("scale-list") description = (request.POST.get("description") or "").strip() scale_id = (request.POST.get("scale_id") or"").strip() if not id_ or not description or not scale_id: messages.error(request, "Scale id, and name are required.") return redirect("scale-list") lang = get_object_or_404(Scale, pk=id_) # Check unique (ignore current row) if Scale.objects.exclude(pk=id_).filter(scale_id__iexact=scale_id).exists(): messages.error(request, "Scale id already exists.") return redirect("scale-list") # unique check stays the same... try: with transaction.atomic(): changed = False if lang.description != description: lang.description = description; changed = True if lang.scale_id != scale_id: lang.scale_id = scale_id; changed =True if not changed: messages.info(request, "No changes detected.") return redirect("scale-list") lang.updated_by = user_profile lang.save(update_fields=["description","scale_id","updated_by", "updated_At"]) messages.success(request, "Scale updated successfully.") return redirect("scale-list") except Exception as e: messages.error(request, f"Update failed: {e}") return redirect("scale-list") @method_decorator(cache_control(no_cache=True, must_revalidate=True, no_store=True), name='dispatch') class DeleteScaleView(View): this_feature = "delete_scale" # Handles: POST /delete-scale (id is taken from form) def post(self, request): context = {} user_profile = set_user_profile(request, context) if user_profile is None: return redirect('login') get_privilleges(user_profile, context) if not is_authorized(user_profile, self.this_feature): return redirect('unauthorized-access') try: id_ = int(request.POST.get("id") or 0) except ValueError: messages.error(request, "Invalid scale id.") return redirect("scale-list") if not id_: messages.error(request, "Missing scale id.") return redirect("scale-list") scale_id = get_object_or_404(Scale, pk=id_) try: with transaction.atomic(): scale_id.delete() messages.success(request, "Scale deleted.") return redirect("scale-list") except ProtectedError: messages.error(request, "Deletion blocked: related data exists.") return redirect("scale-list") except IntegrityError: messages.error(request, "Deletion failed due to related constraints.") return redirect("scale-list") except Exception as e: messages.error(request, f"Unexpected error during delete: {e}") return redirect("scale-list") @method_decorator(cache_control(no_cache=True, must_revalidate=True, no_store=True), name='dispatch') class AddScaleCropMappingView(View): this_feature = "add_scalecropmapping" sub_menu_item = "add_scalecropmapping" def get(self, request): context = get_local_master_details_for_add_update_scalecropmapping() user_profile = set_user_profile(request, context) if user_profile is None: return redirect("login") get_privilleges(user_profile, context) if not is_authorized(user_profile, self.this_feature): return redirect("unauthorized-access") set_sub_menu_item(self.sub_menu_item, context) return render(request, "add-scalecropmapping.html", context) def post(self, request): context = get_local_master_details_for_add_update_scalecropmapping() user_profile = set_user_profile(request, context) if user_profile is None: return redirect("login") get_privilleges(user_profile, context) if not is_authorized(user_profile, self.this_feature): return redirect("unauthorized-access") set_sub_menu_item(self.sub_menu_item, context) # ---- Raw inputs (IDs for FKs expected from the form) ---- scale_id = (request.POST.get("scale") or "").strip() crop_id = (request.POST.get("crop") or "").strip() scale_order_number = (request.POST.get("scale_order_number") or "").strip() universal_moisture_threshold = (request.POST.get("universal_moisture_threshold") or "").strip() # Keep what the user typed to re-fill the form on error def keep_form_values(): context["form_values"] = { "scale": scale_id, "crop": crop_id, "scale_order_number": scale_order_number, "universal_moisture_threshold": universal_moisture_threshold, } # ---- Required fields check ---- if not scale_id or not crop_id: messages.error(request, "Scale and crop are required.") keep_form_values() return render(request, "add-scalecropmapping.html", context) # ---- Resolve FKs ---- try: scale = Scale.objects.get(pk=scale_id) crop = Crop.objects.get(pk=crop_id) except ObjectDoesNotExist: messages.error(request, "Invalid scale or crop selection.") keep_form_values() return render(request, "add-scalecropmapping.html", context) # ---- Parse optional numeric field (no range validation) ---- umt = None if universal_moisture_threshold: try: # Use Decimal to match DecimalField and avoid float quirks umt = Decimal(universal_moisture_threshold) except (InvalidOperation, ValueError): messages.error(request, "Moisture threshold must be a numeric value.") keep_form_values() return render(request, "add-scalecropmapping.html", context) # ---- Create with race-safety & unique-pair handling ---- try: with transaction.atomic(): mapping = ScaleCropMapping.objects.create( scale=scale, crop=crop, scale_order_number=scale_order_number, universal_moisture_threshold=umt, created_user=user_profile, updated_user=user_profile, ) except IntegrityError: # UniqueConstraint(fields=['scale','crop']) hit messages.error(request, "That scale is already mapped to this crop.") keep_form_values() return render(request, "add-scalecropmapping.html", context) messages.success( request, f'Mapping created: "{mapping.scale.scale_id} ↔ {mapping.crop.name}".' ) return redirect("view-scalecropmapping", id=mapping.id) @method_decorator(cache_control(no_cache=True, must_revalidate=True, no_store=True), name='dispatch') class ViewScaleCropMappingView(View): this_feature = "view_scalecropmapping" sub_menu_item = "scalecropmapping_details" def get(self, request, id): context = get_local_master_details_for_scalecropmapping_details() user_profile = set_user_profile(request, context) if user_profile is None: return redirect('login') get_privilleges(user_profile, context) if not is_authorized(user_profile, self.this_feature): return redirect('unauthorized-access') set_sub_menu_item(self.sub_menu_item, context) # Read-only fetch; no transaction needed mapping = get_object_or_404( ScaleCropMapping.objects.select_related('scale', 'crop'), pk=id ) context["mapping"] = mapping return render(request, 'view-scalecropmapping.html', context) @method_decorator(cache_control(no_cache=True, must_revalidate=True,no_store=True), name='dispatch') class ScaleCropMappingDetailsView(View): this_feature = "scalecropmapping_details" sub_menu_item = "scalecropmapping_details" def get(self, request): context = get_local_master_details_for_scalecropmapping_details() user_profile = set_user_profile(request,context) if user_profile==None: return redirect('login') get_privilleges(user_profile,context) if not is_authorized(user_profile,self.this_feature): return redirect('unauthorized-access') set_sub_menu_item(self.sub_menu_item,context) crop = request.GET.get('crop') scale = request.GET.get('scale') scale_order_number = request.GET.get('scale_order_number') # is_active = request.GET.get('is_active') per_page_count = request.GET.get('per_page_count') page_number = request.GET.get('page_number') start_index = request.GET.get('start_index') if not page_number: page_number = 1 if not per_page_count: per_page_count = PerPageSelector.get_default().value if start_index: page_number = math.ceil(int(start_index)/int(per_page_count)) #filter logic applies here filter_kwargs = {} if scale_order_number: context["default_scale_order_number"] = scale_order_number filter_kwargs['scale_order_number__icontains']= scale_order_number if scale: context ["default_scale"] = scale filter_kwargs["scale__scale_id__iexact"] = scale if crop: context["default_crop"] = crop filter_kwargs['crop__name']= crop # if is_active: # if is_active.lower()!="all": # context["default_is_active"] = ActiveStatus(is_active).value # filter_kwargs['is_active']= ActiveStatus(is_active).value mapping_list = ScaleCropMapping.objects.filter(**filter_kwargs).order_by('-id') if len(mapping_list)>0: context["has_entries"] = True else: context["has_entries"] = False paginator = Paginator(mapping_list,per_page_count) page = Paginator.get_page(paginator,page_number) page_list = list(paginator.get_elided_page_range(page_number, on_each_side=1)) context["page"] = page context["page_list"] = page_list return render(request, 'scalecropmapping-details.html', context) @method_decorator(cache_control(no_cache=True, must_revalidate=True, no_store=True), name="dispatch") class UpdateScaleCropMappingView(View): this_feature = "update_scalecropmapping" sub_menu_item = "scalecropmapping_details" def get(self, request, id): context = get_local_master_details_for_add_update_scalecropmapping() user_profile = set_user_profile(request, context) if user_profile is None: return redirect("login") get_privilleges(user_profile, context) if not is_authorized(user_profile, self.this_feature): return redirect("unauthorized-access") set_sub_menu_item(self.sub_menu_item, context) mapping = get_object_or_404( ScaleCropMapping.objects.select_related("scale", "crop"), pk=id ) context["mapping"] = mapping context["old_input_field_values"] = { "scale": str(mapping.scale_id), "crop": str(mapping.crop_id), "scale_order_number": mapping.scale_order_number or "", "universal_moisture_threshold": "" if mapping.universal_moisture_threshold is None else str(mapping.universal_moisture_threshold), } return render(request, "update-scalecropmapping.html", context) def post(self, request, id): context = get_local_master_details_for_add_update_scalecropmapping() user_profile = set_user_profile(request, context) if user_profile is None: return redirect("login") get_privilleges(user_profile, context) if not is_authorized(user_profile, self.this_feature): return redirect("unauthorized-access") set_sub_menu_item(self.sub_menu_item, context) mapping = get_object_or_404( ScaleCropMapping.objects.select_related("scale", "crop"), pk=id ) context["mapping"] = mapping scale_id = (request.POST.get("scale") or "").strip() crop_id = (request.POST.get("crop") or "").strip() scale_order_number = (request.POST.get("scale_order_number") or "").strip() universal_moisture_threshold = (request.POST.get("universal_moisture_threshold") or "").strip() context["old_input_field_values"] = { "scale": scale_id, "crop": crop_id, "scale_order_number": scale_order_number, "universal_moisture_threshold": universal_moisture_threshold, } if not scale_id or not crop_id: messages.error(request, "Scale and crop are required.") return render(request, "update-scalecropmapping.html", context) try: scale = Scale.objects.get(pk=scale_id) crop = Crop.objects.get(pk=crop_id) except (Scale.DoesNotExist, Crop.DoesNotExist): messages.error(request, "Invalid scale or crop selection.") return render(request, "update-scalecropmapping.html", context) umt = None if universal_moisture_threshold: try: umt = Decimal(universal_moisture_threshold) except (InvalidOperation, ValueError): messages.error(request, "Moisture threshold must be a numeric value.") return render(request, "update-scalecropmapping.html", context) try: with transaction.atomic(): mapping.scale = scale mapping.crop = crop mapping.scale_order_number = scale_order_number mapping.universal_moisture_threshold = umt mapping.updated_user = user_profile mapping.updated_at =now() mapping.save() except IntegrityError: messages.error(request, "Another mapping already exists for that Scale ↔ Crop pair.") return render(request, "update-scalecropmapping.html", context) messages.success(request, f'Updated mapping: "{mapping.scale.scale_id} ↔ {mapping.crop.name}".') return redirect("view-scalecropmapping", id=mapping.id) @method_decorator(cache_control(no_cache=True, must_revalidate=True, no_store=True), name='dispatch') class DeleteScaleCropMappingView(View): this_feature = "delete_scalecropmapping" sub_menu_item = "scalecropmapping_details" def post(self, request): context = get_local_master_details_for_scalecropmapping_details() user_profile = set_user_profile(request, context) if user_profile is None: return redirect('login') get_privilleges(user_profile, context) if not is_authorized(user_profile, self.this_feature): return redirect('unauthorized-access') set_sub_menu_item(self.sub_menu_item, context) mapping_id = (request.POST.get('mapping_id') or '').strip() if not mapping_id: messages.error(request, "No mapping id provided.") return redirect('scalecropmapping-details') # Fetch the mapping first (no lock yet) mapping = ScaleCropMapping.objects.select_related("scale", "crop").filter(pk=mapping_id).first() if not mapping: messages.error(request, "Scale–Crop mapping not found.") return redirect('scalecropmapping-details') # 1) Pre-check for dependencies (reverse relations) blockers = find_reverse_dependencies(mapping) if blockers: # Build a friendly message listing what blocks the deletion lines = [] for label, ids in blockers.items(): lines.append(f"{label} (example ids: {', '.join(map(str, ids))})") msg = "Cannot delete: this mapping is referenced by other records → " + "; ".join(lines) messages.error(request, msg) return redirect('scalecropmapping-details') # 2) No blockers found; lock + delete atomically to prevent race try: with transaction.atomic(): # Lock the same row before deleting, to avoid a new reference being created mid-flight locked = ScaleCropMapping.objects.select_for_update().get(pk=mapping.pk) # Double-check dependencies right before delete (TOCTOU safety) blockers_now = find_reverse_dependencies(locked) if blockers_now: lines = [] for label, ids in blockers_now.items(): lines.append(f"{label} (example ids: {', '.join(map(str, ids))})") msg = "Cannot delete (just referenced): " + "; ".join(lines) messages.error(request, msg) return redirect('scalecropmapping-details') scale_name = locked.scale.scale_id crop_name = locked.crop.name locked.delete() messages.success(request, f'Mapping "{scale_name} ↔ {crop_name}" deleted.') return redirect('scalecropmapping-details') except ScaleCropMapping.DoesNotExist: messages.error(request, "Scale–Crop mapping not found.") return redirect('scalecropmapping-details') except Exception as e: # Fallback: if your DB-level FKs are RESTRICT/PROTECT, this will still be safe. messages.error(request, f"Could not delete. {e}") return redirect('scalecropmapping-details') @method_decorator(cache_control(no_cache=True, must_revalidate=True, no_store=True), name="dispatch") class ScaleCropMappingsByQuery(APIView): permission_classes = [AllowAny] def get(self, request): scale_id = request.query_params.get("scale_id") # Validate query param if not scale_id: return JsonResponse( { "success": False, "message": get_api_message("MISSING_SCALE_ID", request), "code": "MISSING_SCALE_ID", "errors": {"scale_id": ["This query parameter is required."]}, }, status=400, ) # Validate scale exists if not Scale.objects.filter(pk=scale_id).exists(): return JsonResponse( { "success": False, "message": get_api_message("SCALE_NOT_FOUND", request), "code": "SCALE_NOT_FOUND", "errors": {"scale_id": [f"No scale with id {scale_id}."]}, }, status=404, ) # Fetch relevant mappings qs = ( ScaleCropMapping.objects .filter(scale_id=scale_id) .select_related("crop") .order_by("scale_order_number") ) data = ScaleCropMappingLiteSerializer(qs, many=True).data return JsonResponse( { "success": True, "message": get_api_message("MAPPINGS_FETCHED", request), "code": "MAPPINGS_FETCHED", "data": data, # list directly }, status=200, )