Add zap utils

packages/util/Address.ts

@@ -49,9 +49,6 @@ export const getIdentifier = (e: UnsignedEvent) => e.tags.find(t => t[0] === "d"
 export const addressFromEvent = (e: UnsignedEvent, relays: string[] = []) =>
   ({kind: e.kind, pubkey: e.pubkey, identifier: getIdentifier(e), relays})
 
-export const addressToFilter = (a: Address) =>
-  ({kinds: [a.kind], authors: [a.pubkey], "#d": [a.identifier]})
-
 // Utils
 
 export const isGroupAddress = (a: Address) => a.kind === GROUP_DEFINITION

packages/util/Events.ts

@@ -5,7 +5,9 @@ import {Tags} from './Tags'
 import {addressFromEvent, encodeAddress} from './Address'
 import {isEphemeralKind, isReplaceableKind, isPlainReplaceableKind, isParameterizedReplaceableKind} from './Kinds'
 
-export type Rumor = Pick<Event, 'kind' | 'tags' | 'content' | 'created_at' | 'pubkey' | 'id'>
+export type Rumor = Pick<Event, 'kind' | 'tags' | 'content' | 'created_at' | 'pubkey' | 'id'> & {
+  wrap?: Event
+}
 
 export type CreateEventOpts = {
   content?: string

packages/util/Filters.ts

@@ -1,5 +1,9 @@
 import type {Event} from 'nostr-tools'
 import {matchFilter as nostrToolsMatchFilter} from 'nostr-tools'
+import {prop, groupBy, randomId, uniq} from '@coracle.social/lib'
+import type {Rumor} from './Events'
+import {decodeAddress, addressFromEvent, encodeAddress} from './Address'
+import {isReplaceableKind} from './Kinds'
 
 export type Filter = {
   ids?: string[]
@@ -42,3 +46,111 @@ export const matchFilters = (filters: Filter[], event: Event) => {
 
   return false
 }
+
+export const calculateFilterGroup = ({since, until, limit, search, ...filter}: Filter) => {
+  const group = Object.keys(filter)
+
+  if (since) group.push(`since:${since}`)
+  if (until) group.push(`until:${until}`)
+  if (limit) group.push(`limit:${randomId()}`)
+  if (search) group.push(`search:${search}`)
+
+  return group.sort().join("-")
+}
+
+export const combineFilters = (filters: Filter[]) => {
+  const result = []
+
+  for (const group of Object.values(groupBy(calculateFilterGroup, filters))) {
+    const newFilter: Record<string, any> = {}
+
+    for (const k of Object.keys(group[0])) {
+      if (["since", "until", "limit", "search"].includes(k)) {
+        newFilter[k] = (group[0] as Record<string, any>)[k]
+      } else {
+        newFilter[k] = uniq(group.flatMap(prop(k)))
+      }
+    }
+
+    result.push(newFilter as Filter)
+  }
+
+  return result
+}
+
+export const getIdFilters = (idsOrAddresses: string[]) => {
+  const ids = []
+  const aFilters = []
+
+  for (const idOrAddress of idsOrAddresses) {
+    if (idOrAddress.includes(":")) {
+      const {kind, pubkey, identifier} = decodeAddress(idOrAddress)
+
+      if (identifier) {
+        aFilters.push({kinds: [kind], authors: [pubkey], "#d": [identifier]})
+      } else {
+        aFilters.push({kinds: [kind], authors: [pubkey]})
+      }
+    } else {
+      ids.push(idOrAddress)
+    }
+  }
+
+  const filters = combineFilters(aFilters)
+
+  if (ids.length > 0) {
+    filters.push({ids})
+  }
+
+  return filters
+}
+
+export const getReplyFilters = (events: Rumor[], filter: Filter) => {
+  const a = []
+  const e = []
+
+  for (const event of events) {
+    e.push(event.id)
+
+    if (isReplaceableKind(event.kind)) {
+      a.push(encodeAddress(addressFromEvent(event)))
+    }
+
+    if (event.wrap) {
+      e.push(event.wrap.id)
+    }
+  }
+
+  const filters = []
+
+  if (a.length > 0) {
+    filters.push({...filter, "#a": a})
+  }
+
+  if (e.length > 0) {
+    filters.push({...filter, "#e": e})
+  }
+
+  return filters
+}
+
+export const getFilterGenerality = (filter: Filter) => {
+  if (filter.ids || filter["#e"] || filter["#a"]) {
+    return 0
+  }
+
+  const hasTags = Object.keys(filter).find((k: string) => k.startsWith("#"))
+
+  if (filter.authors && hasTags) {
+    return 0.2
+  }
+
+  if (filter.authors) {
+    return Math.min(1, filter.authors.length / 100)
+  }
+
+  return 1
+}
+
+export const guessFilterDelta = (filters: Filter[], max = 60 * 60 * 24) =>
+  Math.round(max * Math.max(0.005, 1 - filters.map(getFilterGenerality).reduce((a, b) => a + b) / filters.length))

packages/util/Zaps.ts

@@ -0,0 +1,126 @@
+import type {Event} from 'nostr-tools'
+import {hexToBech32} from '@coracle.social/lib'
+import {Tags} from "./Tags"
+
+const DIVISORS = {
+  m: BigInt(1e3),
+  u: BigInt(1e6),
+  n: BigInt(1e9),
+  p: BigInt(1e12),
+}
+
+const MAX_MILLISATS = BigInt("2100000000000000000")
+
+const MILLISATS_PER_BTC = BigInt(1e11)
+
+export const hrpToMillisat = (hrpString: string) => {
+  let divisor, value
+  if (hrpString.slice(-1).match(/^[munp]$/)) {
+    divisor = hrpString.slice(-1)
+    value = hrpString.slice(0, -1)
+  } else if (hrpString.slice(-1).match(/^[^munp0-9]$/)) {
+    throw new Error("Not a valid multiplier for the amount")
+  } else {
+    value = hrpString
+  }
+
+  if (!value.match(/^\d+$/)) throw new Error("Not a valid human readable amount")
+
+  const valueBN = BigInt(value)
+
+  const millisatoshisBN = divisor
+    ? (valueBN * MILLISATS_PER_BTC) / (DIVISORS as any)[divisor]
+    : valueBN * MILLISATS_PER_BTC
+
+  if (
+    (divisor === "p" && !(valueBN % BigInt(10) === BigInt(0))) ||
+    millisatoshisBN > MAX_MILLISATS
+  ) {
+    throw new Error("Amount is outside of valid range")
+  }
+
+  return millisatoshisBN
+}
+
+export const getInvoiceAmount = (bolt11: string) => {
+  const hrp = bolt11.match(/lnbc(\d+\w)/)
+  const bn = hrpToMillisat(hrp![1])
+  return Number(bn)
+}
+
+export const getLnUrl = (address: string) => {
+  if (address.startsWith("lnurl1")) {
+    return address
+  }
+
+  // If it's a regular url, just encode it
+  if (address.includes("://")) {
+    return hexToBech32("lnurl", address)
+  }
+
+  // Try to parse it as a lud16 address
+  if (address.includes("@")) {
+    const [name, domain] = address.split("@")
+
+    if (domain && name) {
+      return hexToBech32("lnurl", `https://${domain}/.well-known/lnurlp/${name}`)
+    }
+  }
+
+  return null
+}
+
+export type Zapper = {
+  lnurl: string
+  pubkey: string,
+  callback: string
+  minSendable: number
+  maxSendable: number
+  nostrPubkey: string
+  allowsNostr: boolean
+}
+
+export type Zap = {
+  request: Event
+  response: Event,
+  invoiceAmount: number
+}
+
+export const zapFromEvent = (response: Event, zapper: Zapper) => {
+  const responseMeta = Tags.fromEvent(response).asObject()
+
+  let zap: Zap
+  try {
+    zap = {
+      response,
+      invoiceAmount: getInvoiceAmount(responseMeta.bolt11),
+      request: JSON.parse(responseMeta.description),
+    }
+  } catch (e) {
+    return null
+  }
+
+  // Don't count zaps that the user sent himself
+  if (zap.request.pubkey === zapper.pubkey) {
+    return null
+  }
+
+  const {amount, lnurl} = Tags.fromEvent(zap.request).asObject()
+
+  // Verify that the zapper actually sent the requested amount (if it was supplied)
+  if (amount && parseInt(amount) !== zap.invoiceAmount) {
+    return null
+  }
+
+  // If the sending client provided an lnurl tag, verify that too
+  if (lnurl && lnurl !== zapper.lnurl) {
+    return null
+  }
+
+  // Verify that the request actually came from the recipient's zapper
+  if (zap.response.pubkey !== zapper.nostrPubkey) {
+    return null
+  }
+
+  return zap
+}

packages/util/index.ts

@@ -6,3 +6,4 @@ export * from './Links'
 export * from './Relays'
 export * from './Router'
 export * from './Tags'
+export * from './Zaps'

packages/util/package.json

@@ -20,10 +20,8 @@
     }
   },
   "scripts": {
-    "pub": "npm run lint && npm run rebuild && npm publish",
-    "rebuild": "npm run clean && npm run build",
-    "build": "tsc-multi",
-    "clean": "gts clean",
+    "pub": "npm run lint && npm run build && npm publish",
+    "build": "gts clean && tsc-multi",
     "lint": "gts lint",
     "fix": "gts fix"
   },

packages/util/tsconfig.json

@@ -5,7 +5,7 @@
     "outDir": "build",
     "esModuleInterop": true,
     "skipLibCheck": true,
-    "lib": ["es2019"]
+    "lib": ["esnext"]
   },
   "include": ["**/*.ts"]
 }