Get routing working

package.json

@@ -15,10 +15,10 @@
   "types": "./build/src/main.d.ts",
   "exports": {
     ".": {
+      "types": "./build/src/main.d.ts",
       "import": "./build/src/main.mjs",
       "require": "./build/src/main.cjs"
-    },
-    "./types": "./build/src/main.d.ts"
+    }
   },
   "files": [
     "build"

src/connect/Subscription.ts

@@ -1,6 +1,7 @@
 import EventEmitter from "events"
 import type {Event} from 'nostr-tools'
 import type {Executor} from "./Executor"
+import type {Connection} from './Connection'
 import type {Filter} from '../util/Filters'
 import {matchFilters} from "../util/Filters"
 import {hasValidSignature} from "../util/Events"
@@ -116,7 +117,7 @@ export class Subscription extends EventEmitter {
       this.emit("close")
       this.removeAllListeners()
 
-      target.connections.forEach(con => con.off("close", this.closeHandlers.get(con.url)))
+      target.connections.forEach((con: Connection) => con.off("close", this.closeHandlers.get(con.url)))
       target.cleanup()
     }
   }

src/main.ts

@@ -8,6 +8,7 @@ export * from "./connect/target/Multi"
 export * from "./connect/target/Plex"
 export * from "./connect/target/Relay"
 export * from "./connect/target/Relays"
+export * from "./util/Address"
 export * from "./util/Deferred"
 export * from "./util/Emitter"
 export * from "./util/Events"

src/util/Address.ts

@@ -7,7 +7,7 @@ export const isGroupAddress = (a: string) => a.startsWith(`${GROUP_DEFINITION}:`
 
 export const isCommunityAddress = (a: string) => a.startsWith(`${COMMUNITY_DEFINITION}:`)
 
-export const isCommunityOrGroupAddress = (a: string) => isCommunityAddress(a) || isGroupAddress(a)
+export const isContextAddress = (a: string) => isCommunityAddress(a) || isGroupAddress(a)
 
 export class Address {
   readonly kind: number
@@ -23,24 +23,14 @@ export class Address {
   }
 
   static fromEvent = (e: UnsignedEvent, relays: string[] = []) =>
-    new Address(e.kind, e.pubkey, Tags.fromEvent(e).whereKey("d").values().first(), relays)
+    new Address(e.kind, e.pubkey, Tags.fromEvent(e).get("d")?.value() || "", relays)
 
-  static fromTagValue = (a: string, relays: string[] = []) => {
+  static fromRaw = (a: string, relays: string[] = []) => {
     const [kind, pubkey, identifier] = a.split(":")
 
     return new Address(kind, pubkey, identifier, relays)
   }
 
-  static fromTag = (tag: string[], relays: string[] = []) => {
-    const [a, hint] = tag.slice(1)
-
-    if (hint) {
-      relays = relays.concat(hint)
-    }
-
-    return this.fromTagValue(a, relays)
-  }
-
   static fromNaddr = (naddr: string) => {
     let type
     let data = {} as any
@@ -60,10 +50,10 @@ export class Address {
     return new Address(data.kind, data.pubkey, data.identifier, data.relays)
   }
 
-  asTagValue = () => [this.kind, this.pubkey, this.identifier].join(":")
+  asRaw = () => [this.kind, this.pubkey, this.identifier].join(":")
 
   asTag = (mark?: string) => {
-    const tag = ["a", this.asTagValue(), this.relays[0] || ""]
+    const tag = ["a", this.asRaw(), this.relays[0] || ""]
 
     if (mark) {
       tag.push(mark)

src/util/Events.ts

@@ -1,4 +1,4 @@
-import type {Event, EventTemplate} from 'nostr-tools'
+import type {Event, EventTemplate, UnsignedEvent} from 'nostr-tools'
 import {verifyEvent, getEventHash} from 'nostr-tools'
 import {cached} from "./LRUCache"
 import {now} from './Tools'
@@ -16,6 +16,15 @@ export type CreateEventOpts = {
 export const createEvent = (kind: number, {content = "", tags = [], created_at = now()}: CreateEventOpts) =>
   ({kind, content, tags, created_at})
 
+export const asEventTemplate = ({kind, tags, content, created_at}: EventTemplate): EventTemplate =>
+  ({kind, tags, content, created_at})
+
+export const asUnsignedEvent = ({kind, tags, content, created_at, pubkey}: UnsignedEvent): UnsignedEvent =>
+  ({kind, tags, content, created_at, pubkey})
+
+export const asRumor = ({kind, tags, content, created_at, pubkey, id}: Rumor): Rumor =>
+  ({kind, tags, content, created_at, pubkey, id})
+
 export const hasValidSignature = cached<string, boolean, [Event]>({
   maxSize: 10000,
   getKey: ([e]: [Event]) => {
@@ -34,15 +43,12 @@ export const hasValidSignature = cached<string, boolean, [Event]>({
   },
 })
 
-export const getAddress = (e: Rumor) => Address.fromEvent(e).asTagValue()
+export const getAddress = (e: UnsignedEvent) => Address.fromEvent(e).asRaw()
 
 export const getIdOrAddress = (e: Rumor) => isReplaceable(e) ? getAddress(e) : e.id
 
 export const getIdAndAddress = (e: Rumor) => isReplaceable(e) ? [e.id, getAddress(e)] : [e.id]
 
-export const getIdOrAddressTag = (e: Rumor, hint: string) =>
-  isReplaceable(e) ? ["a", getAddress(e), hint] : ["e", e.id, hint]
-
 export const isEphemeral = (e: EventTemplate) => isEphemeralKind(e.kind)
 
 export const isReplaceable = (e: EventTemplate) => isReplaceableKind(e.kind)

src/util/Fluent.ts

@@ -3,6 +3,10 @@ import {last} from './Tools'
 export class Fluent<T> {
   constructor(readonly xs: T[]) {}
 
+  static create() {
+    return this.from([])
+  }
+
   static from<T>(xs: Iterable<T>) {
     return new Fluent<T>(Array.from(xs))
   }
@@ -23,6 +27,8 @@ export class Fluent<T> {
 
   exists = () => this.xs.length > 0
 
+  has = (v: T) => this.xs.includes(v)
+
   every = (f: (t: T) => boolean) => this.xs.every(f)
 
   some = (f: (t: T) => boolean) => this.xs.some(f)
@@ -43,11 +49,17 @@ export class Fluent<T> {
 
   map = (f: (t: T) => T) => this.clone(this.xs.map(f))
 
-  mapTo = <U>(f: (t: T) => U) => new Fluent(this.xs.map(f))
+  mapTo = <U>(f: (t: T) => U) => Fluent.from(this.xs.map(f))
 
-  flatMap = <U>(f: (t: T) => U[]) => new Fluent(this.xs.flatMap(f))
+  flatMap = <U>(f: (t: T) => U[]) => Fluent.from(this.xs.flatMap(f))
+
+  forEach = (f: (t: T, i: number) => void) => this.xs.forEach(f)
+
+  set = (i: number, x: T) => this.clone([...this.xs.slice(0, i), x, ...this.xs.slice(i + 1)])
 
   concat = (xs: T[]) => this.clone(this.xs.concat(xs))
 
   append = (x: T) => this.concat([x])
+
+  prepend = (x: T) => this.clone([x].concat(this.xs))
 }

src/util/Router.ts

@@ -1,14 +1,26 @@
-import type {Event} from 'nostr-tools'
-import {Tags} from './Tags'
-import {nth, first} from '../util/Tools'
+import type {EventTemplate, UnsignedEvent} from 'nostr-tools'
+import type {Rumor} from './Events'
+import {nip19} from 'nostr-tools'
+import {getAddress, isReplaceable} from './Events'
+import {Tag, Tags} from './Tags'
+import {first, uniq, shuffle} from './Tools'
+import {isGroupAddress, isCommunityAddress} from './Address'
+
+export enum RelayMode {
+  Inbox = "inbox",
+  Outbox = "outbox",
+}
 
 export type RouterOptions = {
   getUserPubkey: () => string | null
-  getGroupRelayTags: (address: string) => string[][]
-  getCommunityRelayTags: (address: string) => string[][]
-  getPubkeyRelayTags: (pubkey: string) => string[][]
-  getFallbackRelayTags: () => string[][]
+  getGroupRelays: (address: string) => string[]
+  getCommunityRelays: (address: string) => string[]
+  getPubkeyInboxRelays: (pubkey: string) => string[]
+  getPubkeyOutboxRelays: (pubkey: string) => string[]
+  getFallbackInboxRelays: () => string[]
+  getFallbackOutboxRelays: () => string[]
   getRelayQuality?: (url: string) => number
+  getDefaultLimit: () => number
 }
 
 // - Fetch from and publish to non-shareable relays, but don't use them for hints
@@ -19,43 +31,36 @@ export class Router {
 
   // Utilities derived from options
 
-  getGroupRelayUrls = (address: string) =>
-    this.options.getGroupRelayTags(address).map(nth(1))
+  getAllPubkeyRelays = (pubkey: string) =>
+    [
+      ...this.options.getPubkeyInboxRelays(pubkey),
+      ...this.options.getPubkeyOutboxRelays(pubkey),
+    ]
 
-  getCommunityRelayUrls = (address: string) =>
-    this.options.getCommunityRelayTags(address).map(nth(1))
-
-  getPubkeyRelayTags = (pubkey: string, mode?: string) => {
-    const tags = this.options.getPubkeyRelayTags(pubkey)
-
-    return mode ? Tags.from(tags).whereMark(mode).valueOf() : tags
-  }
-
-  getPubkeyRelayUrls = (pubkey: string, mode?: string) =>
-    this.getPubkeyRelayTags(pubkey, mode).map(nth(1))
-
-  getUserRelayTags = (mode?: string) => {
+  getUserInboxRelays = () => {
     const pubkey = this.options.getUserPubkey()
 
-    return pubkey ? this.getPubkeyRelayTags(pubkey, mode) : []
+    return pubkey ? this.options.getPubkeyInboxRelays(pubkey) : []
   }
 
-  getUserRelayUrls = (mode?: string) => {
+  getUserOutboxRelays = () => {
     const pubkey = this.options.getUserPubkey()
 
-    return pubkey ? this.getPubkeyRelayUrls(pubkey, mode) : []
+    return pubkey ? this.options.getPubkeyOutboxRelays(pubkey) : []
   }
 
-  getEventGroupOrCommunityRelayUrlGroups = (event: Event, otherGroups: string[][]) => {
-    const groupAddresses = Tags.fromEvent(event).groups().valueOf()
+  getAllUserRelays = () => {
+    const pubkey = this.options.getUserPubkey()
 
-    if (groupAddresses.length > 0) {
-      return groupAddresses.map(this.getGroupRelayUrls)
-    }
+    return pubkey ? this.getAllPubkeyRelays(pubkey) : []
+  }
+
+  getEventContextRelayGroups = (event: EventTemplate) => {
+    const addresses = Tags.fromEvent(event).context().values().valueOf()
 
     return [
-      ...Tags.fromEvent(event).communities().valueOf().map(this.getCommunityRelayUrls),
-      ...otherGroups,
+      ...addresses.filter(isCommunityAddress).map(this.options.getCommunityRelays),
+      ...addresses.filter(isGroupAddress).map(this.options.getGroupRelays),
     ]
   }
 
@@ -64,19 +69,16 @@ export class Router {
   getGroupScores = (groups: string[][]) => {
     const scores: RouteScenarioScores = {}
 
-    // TODO: see if weighting earlier groups slightly heavier improves things
-    for (const urls of groups) {
-      urls.forEach((url, i) => {
-        const score = 1 / (i + 1) / urls.length
-
+    groups.forEach((urls, i) => {
+      for (const url of shuffle(uniq(urls))) {
         if (!scores[url]) {
           scores[url] = {score: 0, count: 0}
         }
 
-        scores[url].score += score
+        scores[url].score += 1 / (i + 1)
         scores[url].count += 1
-      })
-    }
+      }
+    })
 
     // Use log-sum-exp to get a a weighted sum
     for (const [url, score] of Object.entries(scores)) {
@@ -91,95 +93,210 @@ export class Router {
   }
 
   urlsFromScores = (limit: number, scores: RouteScenarioScores) =>
-    Object.entries(scores).sort((a, b) => a[1].score > b[1].score ? 1 : -1).map(pair => pair[0] as string).slice(0, limit)
+    Object.entries(scores).sort((a, b) => a[1].score > b[1].score ? -1 : 1).map(pair => pair[0] as string).slice(0, limit)
 
-  groupsToUrls = (limit: number, groups: string[][]) =>
-    this.urlsFromScores(limit, this.getGroupScores(groups))
+  groupsToUrls = (limit: number, groups: string[][]) => this.urlsFromScores(limit, this.getGroupScores(groups))
+
+  scenario = (options: RouterScenarioOptions) => new RouterScenario(this, options)
+
+  merge = ({fallbackPolicy, scenarios}: {fallbackPolicy: FallbackPolicy, scenarios: RouterScenario[]}) =>
+    this.scenario({fallbackPolicy, getGroups: () => scenarios.map(s => s.getRawUrls())})
 
   // Routing scenarios
 
-  FetchAllDirectMessage = () => new RouterScenario(this, {
-    fallbackPolicy: useMinimalFallbacks("read"),
-    getGroups: () => [this.getUserRelayUrls()],
+  Broadcast = () => this.scenario({
+    fallbackPolicy: useMinimalFallbacks(RelayMode.Outbox),
+    getGroups: () => [this.getAllUserRelays()],
   })
 
-  FetchDirectMessages = (pubkey: string) => new RouterScenario(this, {
-    fallbackPolicy: useMinimalFallbacks("read"),
-    getGroups: () => [this.getUserRelayUrls(), this.getPubkeyRelayUrls(pubkey)],
+  Aggregate = () => this.scenario({
+    fallbackPolicy: useMinimalFallbacks(RelayMode.Inbox),
+    getGroups: () => [this.getAllUserRelays()],
   })
 
-  PublishDirectMessage = (pubkey: string) => new RouterScenario(this, {
-    fallbackPolicy: useMinimalFallbacks("write"),
-    getGroups: () => [this.getUserRelayUrls("write"), this.getPubkeyRelayUrls(pubkey, "read")],
+  NoteToSelf = () => this.scenario({
+    fallbackPolicy: useMaximalFallbacks(RelayMode.Inbox),
+    getGroups: () => [this.getUserInboxRelays()],
   })
 
-  FetchPubkeyEvents = (pubkey: string) => new RouterScenario(this, {
-    fallbackPolicy: useMaximalFallbacks("read"),
-    getGroups: () => [this.getPubkeyRelayUrls(pubkey, "write")],
+  FetchAllMessages = () => this.scenario({
+    fallbackPolicy: useMinimalFallbacks(RelayMode.Inbox),
+    getGroups: () => [this.getAllUserRelays()],
   })
 
-  FetchEvent = (event: Event) => new RouterScenario(this, {
-    fallbackPolicy: useMaximalFallbacks("read"),
-    getGroups: () =>
-      this.getEventGroupOrCommunityRelayUrlGroups(event, [
-        this.getPubkeyRelayUrls(event.pubkey, "write"),
-      ]),
+  FetchMessages = (pubkeys: string[]) => this.scenario({
+    fallbackPolicy: useMinimalFallbacks(RelayMode.Inbox),
+    getGroups: () => [
+      this.getAllUserRelays(),
+      ...pubkeys.map(this.getAllPubkeyRelays)
+    ],
   })
 
-  FetchEventChildren = (event: Event) => new RouterScenario(this, {
-    fallbackPolicy: useMaximalFallbacks("read"),
-    getGroups: () =>
-      this.getEventGroupOrCommunityRelayUrlGroups(event, [
-        this.getPubkeyRelayUrls(event.pubkey, "read"),
-      ]),
+  PublishMessage = (pubkeys: string[]) => this.scenario({
+    fallbackPolicy: useMinimalFallbacks(RelayMode.Outbox),
+    getGroups: () => [
+      this.getUserOutboxRelays(),
+      ...pubkeys.map(this.options.getPubkeyInboxRelays)
+    ],
   })
 
-  FetchEventParent = (event: Event) => new RouterScenario(this, {
-    fallbackPolicy: useMaximalFallbacks("read"),
-    getGroups: () =>
-      this.getEventGroupOrCommunityRelayUrlGroups(event, [
-        Tags.fromEvent(event).replies().relays().valueOf(),
-        this.getPubkeyRelayUrls(event.pubkey, "read"),
-      ]),
+  FetchEvent = (event: UnsignedEvent) => this.scenario({
+    fallbackPolicy: useMaximalFallbacks(RelayMode.Inbox),
+    getGroups: () => [
+      this.options.getPubkeyOutboxRelays(event.pubkey),
+      ...this.getEventContextRelayGroups(event),
+    ],
   })
 
-  FetchEventRoot = (event: Event) => new RouterScenario(this, {
-    fallbackPolicy: useMaximalFallbacks("read"),
-    getGroups: () =>
-      this.getEventGroupOrCommunityRelayUrlGroups(event, [
-        Tags.fromEvent(event).roots().relays().valueOf(),
-        this.getPubkeyRelayUrls(event.pubkey, "read"),
-      ]),
+  FetchEventChildren = (event: UnsignedEvent) => this.scenario({
+    fallbackPolicy: useMaximalFallbacks(RelayMode.Inbox),
+    getGroups: () => [
+      this.options.getPubkeyInboxRelays(event.pubkey),
+      ...this.getEventContextRelayGroups(event),
+    ],
   })
 
-  PublishEvent = (event: Event) => new RouterScenario(this, {
-    fallbackPolicy: useMinimalFallbacks("write"),
-    getGroups: () =>
-      this.getEventGroupOrCommunityRelayUrlGroups(event, [
-        this.getPubkeyRelayUrls(event.pubkey, "write"),
-        ...Tags.fromEvent(event).whereKey("p").values().valueOf().map((pk: string) => this.getPubkeyRelayUrls(pk, "read")),
-      ]),
+  FetchEventParent = (event: UnsignedEvent) => this.scenario({
+    fallbackPolicy: useMaximalFallbacks(RelayMode.Inbox),
+    getGroups: () => [
+      Tags.fromEvent(event).replies().relays().valueOf(),
+      this.options.getPubkeyInboxRelays(event.pubkey),
+      ...this.getEventContextRelayGroups(event),
+    ],
   })
 
-  FetchFromGroup = (address: string) => new RouterScenario(this, {
+  FetchEventRoot = (event: UnsignedEvent) => this.scenario({
+    fallbackPolicy: useMaximalFallbacks(RelayMode.Inbox),
+    getGroups: () => [
+      Tags.fromEvent(event).roots().relays().valueOf(),
+      this.options.getPubkeyInboxRelays(event.pubkey),
+      ...this.getEventContextRelayGroups(event),
+    ],
+  })
+
+  PublishEvent = (event: UnsignedEvent) => this.scenario({
+    fallbackPolicy: useMinimalFallbacks(RelayMode.Outbox),
+    getGroups: () => {
+      const tags = Tags.fromEvent(event)
+      const mentions = tags.values("p").valueOf()
+      const addresses = tags.context().values().valueOf()
+      const groupAddresses = addresses.filter(isGroupAddress)
+      const communityAddresses = addresses.filter(isCommunityAddress)
+
+      // If we're publishing only to private groups, only publish to those groups' relays.
+      // Otherwise, publish to all relays, because it's essentially public.
+      if (groupAddresses.length > 0 && communityAddresses.length === 0) {
+        return groupAddresses.map(this.options.getGroupRelays)
+      }
+
+      return  [
+        this.options.getPubkeyOutboxRelays(event.pubkey),
+        ...groupAddresses.map(this.options.getGroupRelays),
+        ...communityAddresses.map(this.options.getCommunityRelays),
+        ...mentions.map((pk: string) => this.options.getPubkeyInboxRelays(pk)),
+      ]
+    },
+  })
+
+  FetchFromHints = (...groups: string[][]) => this.scenario({
+    fallbackPolicy: useMaximalFallbacks(RelayMode.Inbox),
+    getGroups: () => [...groups, this.getAllUserRelays()],
+  })
+
+  FetchFromPubkey = (pubkey: string) => this.scenario({
+    fallbackPolicy: useMaximalFallbacks(RelayMode.Outbox),
+    getGroups: () => [this.options.getPubkeyOutboxRelays(pubkey)],
+  })
+
+  FetchFromPubkeys = (pubkeys: string[]) => this.scenario({
+    fallbackPolicy: useMaximalFallbacks(RelayMode.Outbox),
+    getGroups: () => pubkeys.map(this.options.getPubkeyOutboxRelays),
+  })
+
+  FetchFromGroup = (address: string) => this.scenario({
     fallbackPolicy: useNoFallbacks(),
-    getGroups: () => [this.getGroupRelayUrls(address)],
+    getGroups: () => [this.options.getGroupRelays(address)],
   })
 
-  PublishToGroup = (address: string) => new RouterScenario(this, {
+  PublishToGroup = (address: string) => this.scenario({
     fallbackPolicy: useNoFallbacks(),
-    getGroups: () => [this.getGroupRelayUrls(address)],
+    getGroups: () => [this.options.getGroupRelays(address)],
   })
 
-  FetchFromCommunity = (address: string) => new RouterScenario(this, {
-    fallbackPolicy: useMaximalFallbacks("read"),
-    getGroups: () => [this.getCommunityRelayUrls(address)],
+  FetchFromCommunity = (address: string) => this.scenario({
+    fallbackPolicy: useMaximalFallbacks(RelayMode.Inbox),
+    getGroups: () => [this.options.getCommunityRelays(address)],
   })
 
-  PublishToCommunity = (address: string) => new RouterScenario(this, {
-    fallbackPolicy: useMaximalFallbacks("write"),
-    getGroups: () => [this.getCommunityRelayUrls(address)],
+  PublishToCommunity = (address: string) => this.scenario({
+    fallbackPolicy: useMaximalFallbacks(RelayMode.Outbox),
+    getGroups: () => [this.options.getCommunityRelays(address)],
   })
+
+  FetchFromContext = (address: string) => {
+    if (isGroupAddress(address)) {
+      return this.FetchFromGroup(address)
+    }
+
+    if (isCommunityAddress(address)) {
+      return this.FetchFromCommunity(address)
+    }
+
+    throw new Error(`Unknown context ${address}`)
+  }
+
+  FetchFromContexts = (addresses: string[]) =>
+    this.merge({
+      fallbackPolicy: useMinimalFallbacks(RelayMode.Outbox),
+      scenarios: addresses.map(this.FetchFromContext),
+    })
+
+  PublishToContext = (address: string) => {
+    if (isGroupAddress(address)) {
+      return this.PublishToGroup(address)
+    }
+
+    if (isCommunityAddress(address)) {
+      return this.PublishToCommunity(address)
+    }
+
+    throw new Error(`Unknown context ${address}`)
+  }
+
+  PublishToContexts = (addresses: string[]) =>
+    this.merge({
+      fallbackPolicy: useMinimalFallbacks(RelayMode.Outbox),
+      scenarios: addresses.map(this.PublishToContext),
+    })
+
+  // Higher level utils that use hints
+
+  tagPubkey = (pubkey: string) =>
+    Tag.from(["p", pubkey, this.FetchFromPubkey(pubkey).getUrl()])
+
+  tagEventId = (event: Rumor, ...extra: string[]) =>
+    Tag.from(["e", event.id, this.FetchEvent(event).getUrl(), ...extra])
+
+  tagEventAddress = (event: UnsignedEvent, ...extra: string[]) =>
+    Tag.from(["a", getAddress(event), this.FetchEvent(event).getUrl(), ...extra])
+
+  tagEvent = (event: Rumor, ...extra: string[]) => {
+    const tags = [this.tagEventId(event, ...extra)]
+
+    if (isReplaceable(event)) {
+      tags.push(this.tagEventAddress(event, ...extra))
+    }
+
+    return new Tags(tags)
+  }
+
+  getNaddr = (event: UnsignedEvent) =>
+    nip19.naddrEncode({
+      kind: event.kind,
+      pubkey: event.pubkey,
+      identifier: Tags.fromEvent(event).get("d")?.value() || "",
+      relays: this.FetchEvent(event).getUrls(3),
+    })
 }
 
 // Router Scenario
@@ -194,24 +311,41 @@ export type RouteScenarioScores = Record<string, {score: number, count: number}>
 export class RouterScenario {
   constructor(readonly router: Router, readonly options: RouterScenarioOptions) {}
 
-  addFallbackUrls = (limit: number, urls: string[]) => {
-    if (urls.length < limit) {
-      const {mode, getLimit} = this.options.fallbackPolicy
-      const fallbackRelayTags = this.router.options.getFallbackRelayTags()
-      const fallbackUrls = Tags.from(fallbackRelayTags).whereMark(mode).values().valueOf()
-      const fallbackLimit = getLimit(limit, urls)
+  getFallbackRelays = () => {
+    switch (this.options.fallbackPolicy.mode) {
+      case RelayMode.Inbox:
+        return this.router.options.getFallbackInboxRelays()
+      case RelayMode.Outbox:
+        return this.router.options.getFallbackOutboxRelays()
+      default:
+        throw new Error(`Invalid relay mode ${this.options.fallbackPolicy.mode}`)
+    }
+  }
 
-      return [...urls, ...fallbackUrls.slice(0, fallbackLimit)]
+  addFallbacks = (limit: number, urls: string[]) => {
+    if (urls.length < limit) {
+      const fallbackRelays = this.getFallbackRelays()
+      const fallbackLimit = this.options.fallbackPolicy.getLimit(limit, urls)
+
+      return [...urls, ...fallbackRelays.slice(0, fallbackLimit)]
     }
 
     return urls
   }
 
-  getUrls = (limit: number, extra: string[] = []) => {
+  getRawUrls = (limit?: number, extra: string[] = []) => {
+    const maxRelays = limit || this.router.options.getDefaultLimit()
     const urlGroups = this.options.getGroups().concat([extra])
-    const urls = this.router.groupsToUrls(limit, urlGroups)
 
-    return this.addFallbackUrls(limit, urls)
+    return this.router.groupsToUrls(maxRelays, urlGroups)
+  }
+
+  getUrls = (limit?: number, extra: string[] = []) => {
+    const maxRelays = limit || this.router.options.getDefaultLimit()
+    const urlGroups = [extra].concat(this.options.getGroups())
+    const urls = this.router.groupsToUrls(maxRelays, urlGroups)
+
+    return this.addFallbacks(maxRelays, urls)
   }
 
   getUrl = () => first(this.getUrls(1))
@@ -219,12 +353,12 @@ export class RouterScenario {
 
 // Fallback Policy
 
-class FallbackPolicy {
+export class FallbackPolicy {
   constructor(readonly mode: string, readonly getLimit: (limit: number, urls: string[]) => number) {}
 }
 
-const useNoFallbacks = () => new FallbackPolicy("read", (limit: number, urls: string[]) => 0)
+export const useNoFallbacks = () => new FallbackPolicy(RelayMode.Inbox, (limit: number, urls: string[]) => 0)
 
-const useMinimalFallbacks = (mode: string) => new FallbackPolicy(mode, (limit: number, urls: string[]) => urls.length === 0 ? 1 : 0)
+export const useMinimalFallbacks = (mode: string) => new FallbackPolicy(mode, (limit: number, urls: string[]) => urls.length === 0 ? 1 : 0)
 
-const useMaximalFallbacks = (mode: string) => new FallbackPolicy(mode, (limit: number, urls: string[]) => Math.max(0, limit - urls.length))
+export const useMaximalFallbacks = (mode: string) => new FallbackPolicy(mode, (limit: number, urls: string[]) => Math.max(0, limit - urls.length))

src/util/Tags.ts

@@ -1,15 +1,31 @@
-import type {EventTemplate} from 'nostr-tools'
+import {EventTemplate} from 'nostr-tools'
+import {nip19} from 'nostr-tools'
 import {Fluent} from './Fluent'
-import type {OmitAllStatics} from './Tools'
+import type {OmitStatics} from './Tools'
 import {last} from './Tools'
 import {isShareableRelayUrl} from './Relays'
-import {isCommunityAddress, isGroupAddress, isCommunityOrGroupAddress} from './Address'
+import {isCommunityAddress, isGroupAddress, isContextAddress} from './Address'
 
-export class Tag extends (Fluent<string> as OmitAllStatics<typeof Fluent<string>>) {
+export class Tag extends (Fluent<string> as OmitStatics<typeof Fluent<string>, 'from'>) {
   static from(xs: Iterable<string>) {
     return new Tag(Array.from(xs))
   }
 
+  static fromNaddr(naddr: string) {
+    const {type, data} = nip19.decode(naddr) as {
+      type: "naddr"
+      data: nip19.AddressPointer
+    }
+
+    if (type !== "naddr") {
+      throw new Error(`Invalid naddr ${naddr}`)
+    }
+
+    const {kind, pubkey, identifier, relays = []} = data
+
+    return Tag.from(["a", [kind, pubkey, identifier].join(':'), ...relays.slice(0, 1)])
+  }
+
   valueOf = () => this.xs
 
   key = () => this.xs[0]
@@ -19,19 +35,25 @@ export class Tag extends (Fluent<string> as OmitAllStatics<typeof Fluent<string>
   mark = () => last(this.xs.slice(2))
 
   entry = () => this.xs.slice(0, 2)
+
+  setKey = (k: string) => this.set(0, k)
+
+  setValue = (v: string) => this.set(1, v)
+
+  setMark = (m: string) => this.xs.length > 2 ? this.set(this.xs.length - 2, m) : this.append(m)
 }
 
-export class Tags extends (Fluent<Tag> as OmitAllStatics<typeof Fluent<Tag>>) {
+export class Tags extends (Fluent<Tag> as OmitStatics<typeof Fluent<Tag>, 'from'>) {
   static from(p: Iterable<string[]>) {
     return new Tags(Array.from(p).map(Tag.from))
   }
 
   static fromEvent(event: EventTemplate) {
-    return Tags.from(event.tags)
+    return Tags.from(event.tags || [])
   }
 
-  static fromEvents(events: Iterable<EventTemplate>) {
-    return Tags.from(Array.from(events).flatMap((e: EventTemplate) => e.tags))
+  static fromEvents(events: EventTemplate[]) {
+    return Tags.from(events.flatMap(e => e.tags || []))
   }
 
   // @ts-ignore
@@ -43,9 +65,17 @@ export class Tags extends (Fluent<Tag> as OmitAllStatics<typeof Fluent<Tag>>) {
 
   whereMark = (mark: string) => this.filter(t => t.mark() === mark)
 
+  removeKey = (key: string) => this.reject(t => t.key() === key)
+
+  removeValue = (value: string) => this.reject(t => t.value() === value)
+
+  removeMark = (mark: string) => this.reject(t => t.mark() === mark)
+
+  get = (key: string) => this.whereKey(key).first()
+
   keys = () => this.mapTo(t => t.key())
 
-  values = () => this.mapTo(t => t.value())
+  values = (key?: string) => (key ? this.whereKey(key) : this).mapTo(t => t.value())
 
   marks = () => this.mapTo(t => t.mark())
 
@@ -55,44 +85,124 @@ export class Tags extends (Fluent<Tag> as OmitAllStatics<typeof Fluent<Tag>>) {
 
   topics = () => this.whereKey("t").values().map((t: string) => t.replace(/^#/, ""))
 
-  getAncestorsLegacy(this: Tags) {
-    // Legacy only supports e tags. Normalize their length to 3
-    const eTags =
-      this
-        .whereKey("e")
-        .map((t: Tag) => t.concat([""]).slice(0, 3))
+  ancestors = () => {
+    const tags = this.filter(t => ["a", "e"].includes(t.key()) && !isContextAddress(t.value()))
+    const roots: string[][] = []
+    const replies: string[][] = []
+    const mentions: string[][] = []
+
+    tags
+      .forEach((t: Tag, i: number) => {
+        if (t.mark() === 'root') {
+          roots.push(t.valueOf())
+        } else if (t.mark() === 'reply') {
+          replies.push(t.valueOf())
+        } else if (t.mark() === 'mention') {
+          mentions.push(t.valueOf())
+        } else if (i === 0) {
+          roots.push(t.valueOf())
+        } else if (i === tags.count() - 1) {
+          replies.push(t.valueOf())
+        } else {
+          mentions.push(t.valueOf())
+        }
+      })
 
     return {
-      roots: eTags.slice(0, 1),
-      replies: eTags.slice(-1),
-      mentions: eTags.slice(1, -1),
+      roots: Tags.from(roots),
+      replies: Tags.from(replies),
+      mentions: Tags.from(mentions),
     }
   }
 
-  getAncestors = (key?: string) => {
-    // If we have a mark, we're not using the legacy format
-    if (!this.some((t: Tag) => t.count() === 4 && ["reply", "root", "mention"].includes(t.mark()))) {
-      return this.getAncestorsLegacy()
-    }
+  roots = () => this.ancestors().roots
 
-    const eTags = this.whereKey("e")
-    const aTags = this.whereKey("a").reject((t: Tag) => isCommunityOrGroupAddress(t.value()))
-    const allTags = eTags.concat(aTags.xs)
+  replies = () => this.ancestors().replies
 
-    return {
-      roots: allTags.whereMark('root').map((t: Tag) => t.take(3)),
-      replies: allTags.whereMark('reply').map((t: Tag) => t.take(3)),
-      mentions: allTags.whereMark('mention').map((t: Tag) => t.take(3)),
-    }
+  mentions = () => this.ancestors().mentions
+
+  root = () => {
+    const roots = this.roots()
+
+    return roots.get("e") || roots.get("a")
   }
 
-  roots = (key?: string) => this.getAncestors(key).roots
+  reply = () => {
+    const replies = this.replies()
 
-  replies = (key?: string) => this.getAncestors(key).replies
+    return replies.get("e") || replies.get("a")
+  }
 
-  groups = () => this.whereKey("a").values().filter(isGroupAddress)
+  parents = () => {
+    const {roots, replies} = this.ancestors()
 
-  communities = () => this.whereKey("a").values().filter(isCommunityAddress)
+    return replies.exists() ? replies: roots
+  }
 
-  communitiesAndGroups = () => this.whereKey("a").values().filter(isCommunityOrGroupAddress)
+  parent = () => {
+    const parents = this.parents()
+
+    return parents.get("e") || parents.get("a")
+  }
+
+  groups = () => this.whereKey("a").filter(t => isGroupAddress(t.value()))
+
+  communities = () => this.whereKey("a").filter(t => isCommunityAddress(t.value()))
+
+  context = () => this.whereKey("a").filter(t => isContextAddress(t.value()))
+
+  asObject = () => {
+    const result: Record<string, string> = {}
+
+    for (const t of this.xs) {
+      result[t.key()] = t.value()
+    }
+
+    return result
+  }
+
+  imeta = (url: string) => {
+    for (const tag of this.whereKey("imeta").xs) {
+      const tags = Tags.from(tag.drop(1).valueOf().map((m: string) => m.split(" ")))
+
+      if (tags.get("url")?.value() === url) {
+        return tags
+      }
+    }
+
+    return null
+  }
+
+  // Generic setters
+
+  addTag = (...args: string[]) => this.append(Tag.from(args))
+
+  setTag = (k: string, ...args: string[]) => this.removeKey(k).addTag(k, ...args)
+
+  // Context
+
+  addContext = (addresses: string[]) => this.concat(addresses.map(a => Tag.from(["a", a])))
+
+  removeContext = () => this.reject(t => t.key() === "a" && isContextAddress(t.value()))
+
+  setContext = (addresses: string[]) => this.removeContext().addContext(addresses)
+
+  // Images
+
+  addImages = (imeta: Tags[]) =>
+    this.concat(imeta.map(tags => Tag.from(["image", tags.get("url").value()])))
+
+  removeImages = () => this.removeKey('image')
+
+  setImages = (imeta: Tags[]) => this.removeImages().addImages(imeta)
+
+  // IMeta
+
+  addIMeta = (imeta: Tags[]) =>
+    this.concat(imeta.map(tags => Tag.from(["imeta", ...tags.valueOf().map(xs => xs.join(" "))])))
+
+  removeIMeta = () => this.removeKey('imeta')
+
+  setIMeta = (imeta: Tags[]) => this.removeIMeta().addIMeta(imeta)
 }
+

src/util/Tools.ts

@@ -14,12 +14,20 @@ export const flatten = <T>(xs: T[]) => xs.flatMap(identity)
 
 export const uniq = <T>(xs: T[]) => Array.from(new Set(xs))
 
+export const shuffle = <T>(xs: T[]): T[] => xs.sort(() => Math.random() > 0.5 ? 1 : -1)
+
 export const isIterable = (x: any) => Symbol.iterator in Object(x)
 
 export const toIterable = (x: any) => isIterable(x) ? x : [x]
 
 export const stripProtocol = (url: string) => url.replace(/.*:\/\//, "")
 
+// https://github.com/microsoft/TypeScript/issues/4628#issuecomment-1147905253
+export type OmitStatics<T, S extends string> =
+    T extends {new(...args: infer A): infer R} ?
+        {new(...args: A): R}&Omit<T, S> :
+        Omit<T, S>;
+
 // https://github.com/microsoft/TypeScript/issues/4628#issuecomment-1147905253
 export type OmitAllStatics<T extends {new(...args: any[]): any, prototype: any}> =
     T extends {new(...args: infer A): infer R, prototype: infer P} ?