Work on feed page

src/lib/feeds.ts

@@ -0,0 +1,78 @@
+import {fromPairs, parseJson, randomId} from "@welshman/lib"
+import {FEED, Address} from "@welshman/util"
+import type {TrustedEvent} from "@welshman/util"
+import {
+  makeIntersectionFeed,
+  hasSubFeeds,
+  isTagFeed,
+  isAuthorFeed,
+  isScopeFeed,
+} from "@welshman/feeds"
+import type {Feed as IFeed} from "@welshman/feeds"
+
+export type Feed = {
+  title: string
+  identifier: string
+  description: string
+  definition: IFeed
+  event?: TrustedEvent
+}
+
+export type PublishedFeed = Omit<Feed, "event"> & {
+  event: TrustedEvent
+}
+
+export const normalizeFeedDefinition = (feed: IFeed) =>
+  hasSubFeeds(feed) ? feed : makeIntersectionFeed(feed)
+
+export const makeFeed = (feed: Partial<Feed> = {}): Feed => ({
+  title: "",
+  description: "",
+  identifier: randomId(),
+  definition: makeIntersectionFeed(),
+  ...feed,
+})
+
+export const readFeed = (event: TrustedEvent) => {
+  const {d: identifier, title = "", description = "", feed = ""} = fromPairs(event.tags)
+  const definition = parseJson(feed) || makeIntersectionFeed()
+
+  return {title, identifier, description, definition, event} as PublishedFeed
+}
+
+export const createFeed = ({identifier, definition, title, description}: Feed) => ({
+  kind: FEED,
+  content: "",
+  tags: [
+    ["d", identifier],
+    ["alt", title],
+    ["title", title],
+    ["description", description],
+    ["feed", JSON.stringify(definition)],
+  ],
+})
+
+export const editFeed = (feed: PublishedFeed) => ({
+  kind: FEED,
+  content: feed.event.content,
+  tags: Object.entries({
+    ...fromPairs(feed.event.tags),
+    title: feed.title,
+    alt: feed.title,
+    description: feed.description,
+    feed: JSON.stringify(feed.definition),
+  }),
+})
+
+export const displayFeed = (feed?: Feed) => feed?.title || "[no name]"
+
+export const isTopicFeed = (f: IFeed) => isTagFeed(f) && f[1] === "#t"
+
+export const isMentionFeed = (f: IFeed) => isTagFeed(f) && f[1] === "#p"
+
+export const isAddressFeed = (f: IFeed) => isTagFeed(f) && f[1] === "#a"
+
+export const isContextFeed = (f: IFeed) =>
+  isTagFeed(f) && f[1] === "#a" && f.slice(2).every(Address.isAddress)
+
+export const isPeopleFeed = (f: IFeed) => isAuthorFeed(f) || isScopeFeed(f)