From b1ce901555a51c7082e242057ffc17a5cbee2cec Mon Sep 17 00:00:00 2001
From: Sepehr Safari <safari.sepehr@gmail.com>
Date: Thu, 15 Feb 2024 01:13:53 +0330
Subject: [PATCH] implement nip75 handlers

---
 nip75.ts | 115 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 115 insertions(+)
 create mode 100644 nip75.ts

diff --git a/nip75.ts b/nip75.ts
new file mode 100644
index 0000000..5b07ea0
--- /dev/null
+++ b/nip75.ts
@@ -0,0 +1,115 @@
+import { Event, EventTemplate } from './core'
+import { ZapGoal } from './kinds'
+
+/**
+ * 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
+}