enhance: Allow switching to a more expensive territory

api/paidAction/itemUpdate.js

@@ -12,12 +12,20 @@ export const paymentMethods = [
   PAID_ACTION_PAYMENT_METHODS.PESSIMISTIC
 ]
 
-export async function getCost ({ id, boost = 0, uploadIds, bio }, { me, models }) {
+async function getBaseCostDifference (oldSubName, newSubName, { models }) {
+  if (oldSubName === newSubName) return 0
+  const oldSub = await models.sub.findUnique({ where: { name: oldSubName }, select: { baseCost: true } })
+  const newSub = await models.sub.findUnique({ where: { name: newSubName }, select: { baseCost: true } })
+  return Math.max(0, (newSub?.baseCost ?? 0) - (oldSub?.baseCost ?? 0))
+}
+
+export async function getCost ({ subName, id, boost = 0, uploadIds, bio }, { me, models }) {
   // the only reason updating items costs anything is when it has new uploads
-  // or more boost
+  // or more boost or is switching to a more expensive sub
   const old = await models.item.findUnique({ where: { id: parseInt(id) } })
   const { totalFeesMsats } = await uploadFees(uploadIds, { models, me })
-  const cost = BigInt(totalFeesMsats) + satsToMsats(boost - old.boost)
+  const baseCostDifference = await getBaseCostDifference(old.subName, subName, { models })
+  const cost = BigInt(totalFeesMsats) + satsToMsats(boost - old.boost) + satsToMsats(baseCostDifference)
 
   if (cost > 0 && old.invoiceActionState && old.invoiceActionState !== 'PAID') {
     throw new Error('creation invoice not paid')

api/resolvers/item.js

@@ -1474,14 +1474,6 @@ export const updateItem = async (parent, { sub: subName, forward, hash, hmac, ..
     throw new GqlInputError('item does not belong to you')
   }
 
-  const differentSub = subName && old.subName !== subName
-  if (differentSub) {
-    const sub = await models.sub.findUnique({ where: { name: subName } })
-    if (sub.baseCost > old.sub.baseCost) {
-      throw new GqlInputError('cannot change to a more expensive sub')
-    }
-  }
-
   // in case they lied about their existing boost
   await validateSchema(advSchema, { boost: item.boost }, { models, me, existingBoost: old.boost })
 

fragments/items.js

@@ -35,6 +35,7 @@ export const ITEM_FIELDS = gql`
       meMuteSub
       meSubscription
       nsfw
+      baseCost
       replyCost
     }
     otsHash

pages/items/[id]/edit.js

@@ -7,26 +7,40 @@ import JobForm from '@/components/job-form'
 import { PollForm } from '@/components/poll-form'
 import { BountyForm } from '@/components/bounty-form'
 import { useState } from 'react'
-import { useQuery } from '@apollo/client'
+import { useQuery, gql } from '@apollo/client'
 import { useRouter } from 'next/router'
 import PageLoading from '@/components/page-loading'
-import { FeeButtonProvider } from '@/components/fee-button'
+import { FeeButtonProvider, postCommentBaseLineItems } from '@/components/fee-button'
 import SubSelect from '@/components/sub-select'
 import useCanEdit from '@/components/use-can-edit'
+import { useMe } from '@/components/me'
 
 export const getServerSideProps = getGetServerSideProps({
   query: ITEM,
   notFound: data => !data.item
 })
 
+const SUB_BASECOST = gql`
+  query Sub($name: String!) {
+    sub(name: $name) {
+      name
+      baseCost
+    }
+  }
+`
+
 export default function PostEdit ({ ssrData }) {
   const router = useRouter()
   const { data } = useQuery(ITEM, { variables: { id: router.query.id } })
   if (!data && !ssrData) return <PageLoading />
 
   const { item } = data || ssrData
+  const { me } = useMe()
   const [sub, setSub] = useState(item.subName)
 
+  // we need to fetch the new sub to calculate the cost difference
+  const { data: newSubData } = useQuery(SUB_BASECOST, { variables: { name: sub } })
+
   const [,, editThreshold] = useCanEdit(item)
 
   let FormType = DiscussionForm
@@ -45,20 +59,35 @@ export default function PostEdit ({ ssrData }) {
     itemType = 'BOUNTY'
   }
 
-  const existingBoostLineItem = item.boost
-    ? {
-        existingBoost: {
-          label: 'old boost',
-          term: `- ${item.boost}`,
-          op: '-',
-          modifier: cost => cost - item.boost
+  const editLineItems = (newSub) => {
+    const existingBoostLineItem = item.boost
+      ? {
+          existingBoost: {
+            label: 'old boost',
+            term: `- ${item.boost}`,
+            op: '-',
+            modifier: cost => cost - item.boost
+          }
         }
-      }
-    : undefined
+      : undefined
+
+    const isSwitchingSub = item.subName !== newSub?.name
+    const subCostDifference = isSwitchingSub && {
+      ...postCommentBaseLineItems({
+        baseCost: Math.max(0, (newSub?.baseCost ?? 0) - (item?.sub?.baseCost ?? 0)),
+        me: !!me
+      })
+    }
+
+    return {
+      ...subCostDifference,
+      ...existingBoostLineItem
+    }
+  }
 
   return (
     <CenterLayout sub={sub}>
-      <FeeButtonProvider baseLineItems={existingBoostLineItem}>
+      <FeeButtonProvider baseLineItems={editLineItems(newSubData?.sub)}>
         <FormType item={item} editThreshold={editThreshold}>
           {!item.isJob &&
             <SubSelect