nip75.ts

import { Event, EventTemplate } from './core.ts'
import { ZapGoal } from './kinds.ts'

/**
 * Represents a fundraising goal in the Nostr network as defined by NIP-75.
 * This type is used to structure the information needed to create a goal event (`kind:9041`).
 */
export type Goal = {
  /**
   * A human-readable description of the fundraising goal.
   * This content should provide clear information about the purpose of the fundraising.
   */
  content: string

  /**
   * The target amount for the fundraising goal in milisats.
   * This defines the financial target that the fundraiser aims to reach.
   */
  amount: string

  /**
   * A list of relays where the zaps towards this goal will be sent to and tallied from.
   * Each relay is represented by its WebSocket URL.
   */
  relays: string[]

  /**
   * An optional timestamp (in seconds, UNIX epoch) indicating when the fundraising goal is considered closed.
   * Zaps published after this timestamp should not count towards the goal progress.
   * If not provided, the goal remains open indefinitely or until manually closed.
   */
  closedAt?: number

  /**
   * An optional URL to an image related to the goal.
   * This can be used to visually represent the goal on client interfaces.
   */
  image?: string

  /**
   * An optional brief description or summary of the goal.
   * This can provide a quick overview of the goal, separate from the detailed `content`.
   */
  summary?: string

  /**
   * An optional URL related to the goal, providing additional information or actions through an 'r' tag.
   * This is a single URL, as per NIP-75 specifications for linking additional resources.
   */
  r?: string

  /**
   * An optional parameterized replaceable event linked to the goal, specified through an 'a' tag.
   * This is a single event id, aligning with NIP-75's allowance for linking to specific events.
   */
  a?: string

  /**
   * Optional tags specifying multiple beneficiary pubkeys or additional criteria for zapping,
   * allowing contributions to be directed towards multiple recipients or according to specific conditions.
   */
  zapTags?: string[][]
}

/**
 * Generates an EventTemplate for a fundraising goal based on the provided ZapGoal object.
 * This function is tailored to fit the structure of EventTemplate as defined in the library.
 * @param zapGoal The ZapGoal object containing the details of the fundraising goal.
 * @returns An EventTemplate object structured for creating a Nostr event.
 */
export function generateGoalEventTemplate({
  amount,
  content,
  relays,
  a,
  closedAt,
  image,
  r,
  summary,
  zapTags,
}: Goal): EventTemplate {
  const tags: string[][] = [
    ['amount', amount],
    ['relays', ...relays],
  ]

  // Append optional tags based on the presence of optional properties in zapGoal
  closedAt && tags.push(['closed_at', closedAt.toString()])
  image && tags.push(['image', image])
  summary && tags.push(['summary', summary])
  r && tags.push(['r', r])
  a && tags.push(['a', a])
  zapTags && tags.push(...zapTags)

  // Construct the EventTemplate object
  const eventTemplate: EventTemplate = {
    created_at: Math.floor(Date.now() / 1000),
    kind: ZapGoal,
    content,
    tags,
  }

  return eventTemplate
}

export function validateZapGoalEvent(event: Event): boolean {
  if (event.kind !== ZapGoal) return false

  const requiredTags = ['amount', 'relays'] as const
  for (const tag of requiredTags) {
    if (!event.tags.find(([t]) => t == tag)) return false
  }

  return true
}