implement nip99

nip99.ts

@@ -0,0 +1,229 @@
+import { Event, EventTemplate } from './core.ts'
+import { ClassifiedListing, DraftClassifiedListing } from './kinds.ts'
+import { finalizeEvent, generateSecretKey } from './pure.ts'
+
+/**
+ * Represents the details of a price.
+ * @example { amount: '100', currency: 'USD', frequency: 'month' }
+ * @example { amount: '100', currency: 'EUR' }
+ */
+export type PriceDetails = {
+  /**
+   * The amount of the price.
+   */
+  amount: string
+  /**
+   * The currency of the price in 3-letter ISO 4217 format.
+   * @example 'USD'
+   */
+  currency: string
+  /**
+   * The optional frequency of payment.
+   * Can be one of: 'hour', 'day', 'week', 'month', 'year', or a custom string.
+   */
+  frequency?: string
+}
+
+/**
+ * Represents a classified listing object.
+ */
+export type ClassifiedListingObject = {
+  /**
+   * Whether the listing is a draft or not.
+   */
+  isDraft: boolean
+  /**
+   * A title of the listing.
+   */
+  title: string
+  /**
+   * A short summary or tagline.
+   */
+  summary: string
+  /**
+   * A description in Markdown format.
+   */
+  content: string
+  /**
+   * Timestamp in unix seconds of when the listing was published.
+   */
+  publishedAt: string
+  /**
+   * Location of the listing.
+   * @example 'NYC'
+   */
+  location: string
+  /**
+   * Price details.
+   */
+  price: PriceDetails
+  /**
+   * Images of the listing with optional dimensions.
+   */
+  images: Array<{
+    url: string
+    dimensions?: string
+  }>
+  /**
+   * Tags/Hashtags (i.e. categories, keywords, etc.)
+   */
+  hashtags: string[]
+  /**
+   * Other standard tags.
+   * @example "g", a geohash for more precise location
+   */
+  additionalTags: Record<string, string | string[]>
+}
+
+/**
+ * Validates an event to ensure it is a valid classified listing event.
+ * @param event - The event to validate.
+ * @returns True if the event is valid, false otherwise.
+ */
+export function validateEvent(event: Event): boolean {
+  if (![ClassifiedListing, DraftClassifiedListing].includes(event.kind)) return false
+
+  const requiredTags = ['d', 'title', 'summary', 'location', 'published_at', 'price']
+  const requiredTagCount = requiredTags.length
+  const tagCounts: Record<string, number> = {}
+
+  if (event.tags.length < requiredTagCount) return false
+
+  for (const tag of event.tags) {
+    if (tag.length < 2) return false
+
+    const [tagName, ...tagValues] = tag
+
+    if (tagName == 'published_at') {
+      const timestamp = parseInt(tagValues[0])
+      if (isNaN(timestamp)) return false
+    } else if (tagName == 'price') {
+      if (tagValues.length < 2) return false
+
+      const price = parseInt(tagValues[0])
+      if (isNaN(price) || tagValues[1].length != 3) return false
+    } else if ((tagName == 'e' || tagName == 'a') && tag.length != 3) {
+      return false
+    }
+
+    if (requiredTags.includes(tagName)) {
+      tagCounts[tagName] = (tagCounts[tagName] || 0) + 1
+    }
+  }
+
+  return Object.values(tagCounts).every(count => count == 1) && Object.keys(tagCounts).length == requiredTagCount
+}
+
+/**
+ * Parses an event and returns a classified listing object.
+ * @param event - The event to parse.
+ * @returns The classified listing object.
+ * @throws Error if the event is invalid.
+ */
+export function parseEvent(event: Event): ClassifiedListingObject {
+  if (!validateEvent(event)) {
+    throw new Error('Invalid event')
+  }
+
+  const listing: ClassifiedListingObject = {
+    isDraft: event.kind === DraftClassifiedListing,
+    title: '',
+    summary: '',
+    content: event.content,
+    publishedAt: '',
+    location: '',
+    price: {
+      amount: '',
+      currency: '',
+    },
+    images: [],
+    hashtags: [],
+    additionalTags: {},
+  }
+
+  for (let i = 0; i < event.tags.length; i++) {
+    const tag = event.tags[i]
+    const [tagName, ...tagValues] = tag
+
+    if (tagName == 'title') {
+      listing.title = tagValues[0]
+    } else if (tagName == 'summary') {
+      listing.summary = tagValues[0]
+    } else if (tagName == 'published_at') {
+      listing.publishedAt = tagValues[0]
+    } else if (tagName == 'location') {
+      listing.location = tagValues[0]
+    } else if (tagName == 'price') {
+      listing.price.amount = tagValues[0]
+      listing.price.currency = tagValues[1]
+
+      if (tagValues.length == 3) {
+        listing.price.frequency = tagValues[2]
+      }
+    } else if (tagName == 'image') {
+      listing.images.push({
+        url: tagValues[0],
+        dimensions: tagValues?.[1] ?? undefined,
+      })
+    } else if (tagName == 't') {
+      listing.hashtags.push(tagValues[0])
+    } else if (tagName == 'e' || tagName == 'a') {
+      listing.additionalTags[tagName] = [...tagValues]
+    }
+  }
+
+  return listing
+}
+
+/**
+ * Generates an event template based on a classified listing object.
+ *
+ * @param listing - The classified listing object.
+ * @returns The event template.
+ */
+export function generateEventTemplate(listing: ClassifiedListingObject): EventTemplate {
+  const priceTag = ['price', listing.price.amount, listing.price.currency]
+  if (listing.price.frequency) priceTag.push(listing.price.frequency)
+
+  const tags: string[][] = [
+    ['d', listing.title.trim().toLowerCase().replace(/ /g, '-')],
+    ['title', listing.title],
+    ['published_at', listing.publishedAt],
+    ['summary', listing.summary],
+    ['location', listing.location],
+    priceTag,
+  ]
+
+  for (let i = 0; i < listing.images.length; i++) {
+    const image = listing.images[i]
+    const imageTag = ['image', image.url]
+    if (image.dimensions) imageTag.push(image.dimensions)
+
+    tags.push(imageTag)
+  }
+
+  for (let i = 0; i < listing.hashtags.length; i++) {
+    const t = listing.hashtags[i]
+
+    tags.push(['t', t])
+  }
+
+  for (const [key, value] of Object.entries(listing.additionalTags)) {
+    if (Array.isArray(value)) {
+      for (let i = 0; i < value.length; i++) {
+        const val = value[i]
+
+        tags.push([key, val])
+      }
+    } else {
+      tags.push([key, value])
+    }
+  }
+
+  return {
+    kind: listing.isDraft ? DraftClassifiedListing : ClassifiedListing,
+    content: listing.content,
+    tags,
+    created_at: Math.floor(Date.now() / 1000),
+  }
+}