refactor: improve promotional offers system and use ERPNext native pricing logic

- Add posOffers Pinia store for centralized offer state management
- Enhanced offers API to fetch promotional scheme slab details including
  min/max amounts, discount values, and apply_multiple_pricing_rules flag
- Add eligibility checking and auto-apply logic in offers store
- Update cart to support multiple manual offer selection
- Simplify apply_offers function to use pure ERPNext pricing engine
- Remove all debug code and temporary workarounds
- Update OffersDialog to use new posOffers store for better reactivity
- Format invoices.py with consistent code style (Black formatter)

This refactor allows ERPNext to handle all pricing rule conflicts natively
based on priority, while giving users the ability to manually select from
eligible promotional offers.

Author: Ahmed Osama

POS/src/components/sale/InvoiceCart.vue

@@ -31,20 +31,21 @@
 				</div>
 
 				<!-- Offers List -->
-				<div v-else class="space-y-3 max-h-[500px] overflow-y-auto pr-2">
-					<div
-						v-for="offer in eligibleOffers"
-						:key="offer.name"
-						:class="[
-							'relative rounded-xl p-4 transition-all duration-200 border-2',
-							appliedOffer?.code === offer.name
-								? 'bg-green-50 border-green-500 shadow-md'
-								: 'bg-gradient-to-r from-green-50 to-emerald-50 border-green-200 hover:border-green-400 hover:shadow-lg cursor-pointer'
-						]"
-					>
+				<div v-else>
+					<div class="space-y-3 max-h-[500px] overflow-y-auto pr-2">
+						<div
+							v-for="offer in eligibleOffers"
+							:key="offer.name"
+							:class="[
+								'relative rounded-xl p-4 transition-all duration-200 border-2',
+								isOfferApplied(offer)
+									? 'bg-green-50 border-green-500 shadow-md'
+									: 'bg-gradient-to-r from-green-50 to-emerald-50 border-green-200 hover:border-green-400 hover:shadow-lg cursor-pointer'
+							]"
+						>
 						<!-- Applied Badge -->
 						<div
-							v-if="appliedOffer?.code === offer.name"
+							v-if="isOfferApplied(offer)"
 							class="absolute top-2 right-2 bg-green-600 text-white text-[10px] font-bold px-2 py-1 rounded-full flex items-center space-x-1"
 						>
 							<svg class="w-3 h-3" fill="currentColor" viewBox="0 0 20 20">
@@ -131,22 +132,22 @@
 							</div>
 						</div>
 
-						<!-- Progress Bar for Min Amount -->
-						<div v-if="offer.min_amt && subtotal < offer.min_amt" class="mt-3">
+						<!-- Progress Bar for Min Amount (only shown if not eligible) -->
+						<div v-if="offer.min_amt && offersStore.cartSnapshot.subtotal < offer.min_amt" class="mt-3">
 							<div class="flex items-center justify-between text-xs mb-1">
 								<span class="text-gray-600">Subtotal (before tax)</span>
 								<span class="text-gray-900 font-semibold">
-									{{ formatCurrency(subtotal) }} / {{ formatCurrency(offer.min_amt) }}
+									{{ formatCurrency(offersStore.cartSnapshot.subtotal) }} / {{ formatCurrency(offer.min_amt) }}
 								</span>
 							</div>
 							<div class="w-full bg-gray-200 rounded-full h-2">
 								<div
 									class="bg-green-600 h-2 rounded-full transition-all"
-									:style="{ width: `${Math.min((subtotal / offer.min_amt) * 100, 100)}%` }"
+									:style="{ width: `${Math.min((offersStore.cartSnapshot.subtotal / offer.min_amt) * 100, 100)}%` }"
 								></div>
 							</div>
 							<p class="text-xs text-orange-600 mt-1 font-medium">
-								Add {{ formatCurrency(offer.min_amt - subtotal) }} more to unlock
+								Add {{ formatCurrency(offersStore.getUnlockAmount(offer)) }} more to unlock
 							</p>
 						</div>
 
@@ -157,17 +158,18 @@
 							:disabled="applyingOffer"
 							:class="[
 								'mt-3 w-full py-2 px-4 rounded-lg font-semibold text-sm transition-all',
-								appliedOffer?.code === offer.name
+								isOfferApplied(offer)
 									? 'bg-red-600 hover:bg-red-700 text-white'
 									: 'bg-green-600 hover:bg-green-700 text-white shadow-md hover:shadow-lg',
 								applyingOffer ? 'opacity-70 cursor-not-allowed' : ''
 							]"
 						>
-							{{ appliedOffer?.code === offer.name ? 'Remove Offer' : 'Apply Offer' }}
+							{{ isOfferApplied(offer) ? 'Remove Offer' : 'Apply Offer' }}
 						</button>
 					</div>
 				</div>
 			</div>
+			</div>
 		</template>
 		<template #actions>
 			<div class="flex justify-end w-full">
@@ -181,8 +183,12 @@
 
 <script setup>
 import { ref, watch, computed } from 'vue'
-import { Dialog, Button, createResource, toast } from 'frappe-ui'
+import { Dialog, Button } from 'frappe-ui'
 import { formatCurrency as formatCurrencyUtil } from '@/utils/currency'
+import { usePOSOffersStore } from '@/stores/posOffers'
+
+// Use Pinia stores
+const offersStore = usePOSOffersStore()
 
 const props = defineProps({
 	modelValue: Boolean,
@@ -199,64 +205,31 @@ const props = defineProps({
 		type: String,
 		default: 'USD'
 	},
-	appliedOffer: {
-		type: Object,
-		default: null
+	appliedOffers: {
+		type: Array,
+		default: () => []
 	}
 })
 
 const emit = defineEmits(['update:modelValue', 'apply-offer', 'remove-offer'])
 
 const show = ref(props.modelValue)
-const allOffers = ref([])
-const loading = ref(false)
 const applyingOffer = ref(false)
-
-// Resource to load offers
-const offersResource = createResource({
-	url: 'pos_next.api.offers.get_offers',
-	makeParams() {
-		return {
-			pos_profile: props.posProfile
-		}
-	},
-	auto: false,
-	onSuccess(data) {
-		allOffers.value = data?.message || data || []
-		loading.value = false
-	},
-	onError(error) {
-		console.error('Error loading offers:', error)
-		loading.value = false
-		toast({
-			title: 'Error',
-			text: 'Failed to load offers',
-			icon: 'x',
-			iconClasses: 'text-red-600'
-		})
-	}
+const appliedOfferCodes = computed(() => {
+	return new Set((props.appliedOffers || []).map(entry => entry?.code).filter(Boolean))
 })
 
-// Computed eligible offers - only show offers the user is eligible for
-const eligibleOffers = computed(() => {
-	if (!allOffers.value) return []
+// Use ALL eligible offers from store (includes both auto and manual offers)
+const eligibleOffers = computed(() => offersStore.allEligibleOffersSorted)
 
-	// Filter to only show eligible, non-coupon offers
-	return allOffers.value
-		.filter(offer => !offer.coupon_based && checkOfferEligibility(offer))
-		.sort((a, b) => {
-			// Sort by discount value (higher discounts first)
-			const aValue = a.discount_percentage || a.discount_amount || 0
-			const bValue = b.discount_percentage || b.discount_amount || 0
-			return bValue - aValue
-		})
+// Loading state - check if offers are being loaded
+const loading = computed(() => {
+	return !offersStore.hasFetched && eligibleOffers.value.length === 0
 })
 
 watch(() => props.modelValue, (val) => {
 	show.value = val
-	if (val) {
-		loadOffers()
-	}
+	// No need to load offers - they're already in the store
 })
 
 watch(show, (val) => {
@@ -267,46 +240,16 @@ watch(show, (val) => {
 	}
 })
 
-function checkOfferEligibility(offer) {
-	// Check minimum amount (on subtotal before tax)
-	if (offer.min_amt && props.subtotal < offer.min_amt) {
-		return false
-	}
-	// Check maximum amount (on subtotal before tax)
-	if (offer.max_amt && props.subtotal > offer.max_amt) {
-		return false
-	}
-	// Check minimum quantity
-	if (offer.min_qty) {
-		const totalQty = props.items.reduce((sum, item) => sum + item.quantity, 0)
-		if (totalQty < offer.min_qty) {
-			return false
-		}
-	}
-	return true
-}
-
-async function loadOffers() {
-	if (!props.posProfile) return
-	loading.value = true
-	try {
-		await offersResource.reload()
-	} catch (error) {
-		console.error('Error loading offers:', error)
-		loading.value = false
-	}
-}
-
 async function handleApplyOffer(offer) {
 	if (applyingOffer.value) {
 		return
 	}
 
 	// Toggle offer - if already applied, remove it
-	if (props.appliedOffer?.code === offer.name) {
+	if (isOfferApplied(offer)) {
 		applyingOffer.value = true
 		try {
-			emit('remove-offer')
+			emit('remove-offer', offer)
 			// Close dialog after successful removal
 			await new Promise(resolve => setTimeout(resolve, 500))
 			show.value = false
@@ -335,6 +278,10 @@ function resetApplyingState() {
 // Expose for parent component
 defineExpose({ resetApplyingState })
 
+function isOfferApplied(offer) {
+	return appliedOfferCodes.value.has(offer?.name)
+}
+
 function formatCurrency(amount) {
 	return formatCurrencyUtil(parseFloat(amount || 0), props.currency)
 }

POS/src/components/sale/OffersDialog.vue

@@ -154,6 +154,9 @@ export function useInvoice() {
 				batch_no: item.batch_no,
 				serial_no: item.serial_no,
 				item_uoms: item.item_uoms || [],  // Available UOMs for this item
+				// Add item_group and brand for offer eligibility checking
+				item_group: item.item_group,
+				brand: item.brand,
 			}
 			invoiceItems.value.push(newItem)
 			// Recalculate the newly added item to apply taxes

POS/src/composables/useInvoice.js

@@ -205,7 +205,7 @@
 					:grand-total="cartStore.grandTotal"
 					:pos-profile="shiftStore.profileName"
 					:currency="shiftStore.profileCurrency"
-					:applied-offer="cartStore.autoAppliedOffer"
+					:applied-offers="cartStore.appliedOffers"
 					:warehouses="profileWarehouses"
 					@update-quantity="cartStore.updateItemQuantity"
 					@remove-item="cartStore.removeItem"
@@ -216,7 +216,7 @@
 					@save-draft="handleSaveDraft"
 					@apply-coupon="uiStore.showCouponDialog = true"
 					@show-offers="uiStore.showOffersDialog = true"
-					@remove-offer="cartStore.removeOffer"
+					@remove-offer="offer => cartStore.removeOffer(offer, shiftStore.currentProfile, offersDialogRef.value)"
 					@update-uom="cartStore.changeItemUOM"
 					@edit-item="handleEditItem"
 				/>
@@ -331,9 +331,9 @@
 			:customer="cartStore.customer?.name || cartStore.customer"
 			:company="shiftStore.profileCompany"
 			:currency="shiftStore.profileCurrency"
-			:applied-offer="cartStore.autoAppliedOffer"
+			:applied-offers="cartStore.appliedOffers"
 			@apply-offer="handleApplyOffer"
-			@remove-offer="cartStore.removeOffer"
+			@remove-offer="offer => cartStore.removeOffer(offer, shiftStore.currentProfile, offersDialogRef.value)"
 		/>
 
 		<!-- Batch/Serial Dialog -->