add: Megalodon, initial mastodon api

packages/backend/src/server/api/mastodon/converters.ts

@@ -0,0 +1,136 @@
+import { Entity } from "megalodon";
+
+const CHAR_COLLECTION: string = "0123456789abcdefghijklmnopqrstuvwxyz";
+
+export enum IdConvertType {
+    MastodonId,
+    SharkeyId,
+}
+
+export function convertId(in_id: string, id_convert_type: IdConvertType): string {
+    switch (id_convert_type) {
+        case IdConvertType.MastodonId:
+          let out: bigint = BigInt(0);
+          const lowerCaseId = in_id.toLowerCase();
+          for (let i = 0; i < lowerCaseId.length; i++) {
+            const charValue = numFromChar(lowerCaseId.charAt(i));
+            out += BigInt(charValue) * BigInt(36) ** BigInt(i);
+          }
+          return out.toString();
+    
+        case IdConvertType.SharkeyId:
+          let input: bigint = BigInt(in_id);
+          let outStr = '';
+          while (input > BigInt(0)) {
+            const remainder = Number(input % BigInt(36));
+            outStr = charFromNum(remainder) + outStr;
+            input /= BigInt(36);
+          }
+          return outStr;
+    
+        default:
+          throw new Error('Invalid ID conversion type');
+    }
+}
+
+function numFromChar(character: string): number {
+    for (let i = 0; i < CHAR_COLLECTION.length; i++) {
+      if (CHAR_COLLECTION.charAt(i) === character) {
+        return i;
+      }
+    }
+
+    throw new Error('Invalid character in parsed base36 id');
+}
+
+function charFromNum(number: number): string {
+    if (number >= 0 && number < CHAR_COLLECTION.length) {
+      return CHAR_COLLECTION.charAt(number);
+    } else {
+      throw new Error('Invalid number for base-36 encoding');
+    }
+}
+
+function simpleConvert(data: any) {
+	// copy the object to bypass weird pass by reference bugs
+	const result = Object.assign({}, data);
+	result.id = convertId(data.id, IdConvertType.MastodonId);
+	return result;
+}
+
+export function convertAccount(account: Entity.Account) {
+	return simpleConvert(account);
+}
+export function convertAnnouncement(announcement: Entity.Announcement) {
+	return simpleConvert(announcement);
+}
+export function convertAttachment(attachment: Entity.Attachment) {
+	return simpleConvert(attachment);
+}
+export function convertFilter(filter: Entity.Filter) {
+	return simpleConvert(filter);
+}
+export function convertList(list: Entity.List) {
+	return simpleConvert(list);
+}
+export function convertFeaturedTag(tag: Entity.FeaturedTag) {
+	return simpleConvert(tag);
+}
+
+export function convertNotification(notification: Entity.Notification) {
+	notification.account = convertAccount(notification.account);
+	notification.id = convertId(notification.id, IdConvertType.MastodonId);
+	if (notification.status)
+		notification.status = convertStatus(notification.status);
+	if (notification.reaction)
+		notification.reaction = convertReaction(notification.reaction);
+	return notification;
+}
+
+export function convertPoll(poll: Entity.Poll) {
+	return simpleConvert(poll);
+}
+export function convertReaction(reaction: Entity.Reaction) {
+	if (reaction.accounts) {
+		reaction.accounts = reaction.accounts.map(convertAccount);
+	}
+	return reaction;
+}
+export function convertRelationship(relationship: Entity.Relationship) {
+	return simpleConvert(relationship);
+}
+
+export function convertStatus(status: Entity.Status) {
+	status.account = convertAccount(status.account);
+	status.id = convertId(status.id, IdConvertType.MastodonId);
+	if (status.in_reply_to_account_id)
+		status.in_reply_to_account_id = convertId(
+			status.in_reply_to_account_id,
+			IdConvertType.MastodonId,
+		);
+	if (status.in_reply_to_id)
+		status.in_reply_to_id = convertId(status.in_reply_to_id, IdConvertType.MastodonId);
+	status.media_attachments = status.media_attachments.map((attachment) =>
+		convertAttachment(attachment),
+	);
+	status.mentions = status.mentions.map((mention) => ({
+		...mention,
+		id: convertId(mention.id, IdConvertType.MastodonId),
+	}));
+	if (status.poll) status.poll = convertPoll(status.poll);
+	if (status.reblog) status.reblog = convertStatus(status.reblog);
+	if (status.quote) status.quote = convertStatus(status.quote);
+	status.reactions = status.reactions.map(convertReaction);
+
+	return status;
+}
+
+export function convertConversation(conversation: Entity.Conversation) {
+	conversation.id = convertId(conversation.id, IdConvertType.MastodonId);
+	conversation.accounts = conversation.accounts.map(convertAccount);
+	if (conversation.last_status) {
+		conversation.last_status = convertStatus(conversation.last_status);
+	}
+
+	return conversation;
+}