feat: Add Mollie payment provider support

- Introduce `mollieProvider` for handling Mollie payments
- Add configurable payment hooks for initialization and processing
- Implement `initPayment` logic to create Mollie payments and update metadata
- Include types for Mollie integration in payments and refunds
- Update `package.json` to include `@mollie/api-client` dependency
- Refactor existing payment-related types into modular files for better maintainability

src/collections/hooks.ts

@@ -0,0 +1,11 @@
+import type { Payment } from '@/plugin/types'
+import type { Payload } from 'payload'
+import { useBillingPlugin } from '@/plugin'
+
+export const initProviderPayment = (payload: Payload, payment: Partial<Payment>) => {
+  const billing = useBillingPlugin(payload)
+  if (!payment.provider || !billing.providerConfig[payment.provider]) {
+    throw new Error(`Provider ${payment.provider} not found.`)
+  }
+  return billing.providerConfig[payment.provider].initPayment(payload, payment)
+}

src/collections/invoices.ts

@@ -5,9 +5,10 @@ import {
   CollectionBeforeValidateHook,
   CollectionConfig, Field,
 } from 'payload'
-import { BillingPluginConfig, CustomerInfoExtractor, defaults } from '@/plugin/config'
-import { Invoice } from '@/plugin/types'
+import type { BillingPluginConfig} from '@/plugin/config';
+import { defaults } from '@/plugin/config'
 import { extractSlug } from '@/plugin/utils'
+import type { Invoice } from '@/plugin/types/invoices'
 
 export function createInvoicesCollection(pluginConfig: BillingPluginConfig): CollectionConfig {
   const {customerRelationSlug, customerInfoExtractor} = pluginConfig
@@ -31,7 +32,7 @@ export function createInvoicesCollection(pluginConfig: BillingPluginConfig): Col
         position: 'sidebar' as const,
         description: 'Link to customer record (optional)',
       },
-      relationTo: pluginConfig.customerRelationSlug as never,
+      relationTo: extractSlug(customerRelationSlug),
       required: false,
     }] : []),
     // Basic customer info fields (embedded)
@@ -275,7 +276,7 @@ export function createInvoicesCollection(pluginConfig: BillingPluginConfig): Col
         condition: (data) => data.status === 'paid',
         position: 'sidebar',
       },
-      relationTo: 'payments',
+      relationTo: extractSlug(pluginConfig.collections?.payments || defaults.paymentsCollection),
     },
     {
       name: 'notes',

src/collections/payments.ts

@@ -1,8 +1,9 @@
-import type { AccessArgs, CollectionBeforeChangeHook, CollectionConfig, Field } from 'payload'
-import type { Payment } from '@/plugin/types'
+import type { AccessArgs, CollectionBeforeChangeHook, CollectionConfig, CollectionSlug, Field } from 'payload'
 import type { BillingPluginConfig} from '@/plugin/config';
 import { defaults } from '@/plugin/config'
 import { extractSlug } from '@/plugin/utils'
+import { Payment } from '@/plugin/types/payments'
+import { initProviderPayment } from '@/collections/hooks'
 
 export function createPaymentsCollection(pluginConfig: BillingPluginConfig): CollectionConfig {
   const overrides = typeof pluginConfig.collections?.payments === 'object' ? pluginConfig.collections?.payments : {}
@@ -27,7 +28,6 @@ export function createPaymentsCollection(pluginConfig: BillingPluginConfig): Col
         description: 'The payment ID from the payment provider',
       },
       label: 'Provider Payment ID',
-      required: true,
       unique: true,
     },
     {
@@ -78,7 +78,7 @@ export function createPaymentsCollection(pluginConfig: BillingPluginConfig): Col
       admin: {
         position: 'sidebar',
       },
-      relationTo: 'invoices',
+      relationTo: extractSlug(pluginConfig.collections?.invoices || defaults.invoicesCollection) as CollectionSlug,
     },
     {
       name: 'metadata',
@@ -103,7 +103,7 @@ export function createPaymentsCollection(pluginConfig: BillingPluginConfig): Col
         readOnly: true,
       },
       hasMany: true,
-      relationTo: 'refunds',
+      relationTo: extractSlug(pluginConfig.collections?.refunds || defaults.refundsCollection) as CollectionSlug,
     },
   ]
   if (overrides?.fields) {
@@ -126,7 +126,7 @@ export function createPaymentsCollection(pluginConfig: BillingPluginConfig): Col
     fields,
     hooks: {
       beforeChange: [
-        ({ data, operation }) => {
+        async ({ data, operation, req }) => {
           if (operation === 'create') {
             // Validate amount format
             if (data.amount && !Number.isInteger(data.amount)) {
@@ -140,6 +140,8 @@ export function createPaymentsCollection(pluginConfig: BillingPluginConfig): Col
                 throw new Error('Currency must be a 3-letter ISO code')
               }
             }
+
+            await initProviderPayment(req.payload, data)
           }
         },
       ] satisfies CollectionBeforeChangeHook<Payment>[],

src/collections/refunds.ts

@@ -1,9 +1,9 @@
 import type { AccessArgs, CollectionConfig } from 'payload'
 import { BillingPluginConfig, defaults } from '@/plugin/config'
 import { extractSlug } from '@/plugin/utils'
+import { Payment } from '@/plugin/types'
 
 export function createRefundsCollection(pluginConfig: BillingPluginConfig): CollectionConfig {
-  const overrides = typeof pluginConfig.collections?.invoices === 'object' ? pluginConfig.collections?.invoices : {}
   // TODO: finish collection overrides
   return {
     slug: extractSlug(pluginConfig.collections?.refunds || defaults.refundsCollection),
@@ -35,7 +35,7 @@ export function createRefundsCollection(pluginConfig: BillingPluginConfig): Coll
         admin: {
           position: 'sidebar',
         },
-        relationTo: 'payments',
+        relationTo: extractSlug(pluginConfig.collections?.payments || defaults.paymentsCollection),
         required: true,
       },
       {
@@ -117,13 +117,13 @@ export function createRefundsCollection(pluginConfig: BillingPluginConfig): Coll
             try {
               const payment = await req.payload.findByID({
                 id: typeof doc.payment === 'string' ? doc.payment : doc.payment.id,
-                collection: 'payments',
-              })
+                collection: extractSlug(pluginConfig.collections?.payments || defaults.paymentsCollection),
+              }) as Payment
 
               const refundIds = Array.isArray(payment.refunds) ? payment.refunds : []
               await req.payload.update({
                 id: typeof doc.payment === 'string' ? doc.payment : doc.payment.id,
-                collection: 'payments',
+                collection: extractSlug(pluginConfig.collections?.payments || defaults.paymentsCollection),
                 data: {
                   refunds: [...refundIds, doc.id],
                 },