8 files changed, 532 insertions, 0 deletions
diff --git a/src/lib/nip01.ts b/src/lib/nip01.ts
new file mode 100644
index 00000000..a5d3f4b5
--- /dev/null
+++ b/src/lib/nip01.ts
@@ -0,0 +1,19 @@
+import { PUBLIC_DM_RELAYS, PUBLIC_COINOS_RELAY } from '$env/static/public';
+const DM_RELAYS_LIST = PUBLIC_DM_RELAYS.split(',');
+const USERINFO_RELAYS = [ ...DM_RELAYS_LIST, PUBLIC_COINOS_RELAY ];
+
+import { SimplePool } from 'nostr-tools/pool';
+const pool = new SimplePool();
+
+// Returns the content of the kind-0 event of the provided pubkey.
+export const getNostrUserInfo = async (pubkey: string) => {
+    const events = await pool.querySync(
+        USERINFO_RELAYS, { kinds: [0], limit: 1, authors: [pubkey] }
+    );
+
+    if (events.length == 0) {
+        return null;
+    }
+
+    return JSON.parse(events[0].content);
+}
diff --git a/src/lib/nip07.ts b/src/lib/nip07.ts
new file mode 100644
index 00000000..9f675950
--- /dev/null
+++ b/src/lib/nip07.ts
@@ -0,0 +1,42 @@
+import { bytesToHex } from '@noble/hashes/utils';
+import { finalizeEvent } from 'nostr-tools/pure';
+import { unwrapEvent } from 'nostr-tools/nip17';
+import { getPrivateKey } from '$lib/nostr';
+import * as libnip44 from '$lib/nip44';
+import { u } from '$lib/nip44';
+
+// Signs an event using NIP-07 if available, otherwise getPrivateKey()
+export const signEvent = async (event: object, user: object): object => {
+    if (await window.nostr.getPublicKey() === user.pubkey) {
+        return window.nostr.signEvent(event);
+    } else {
+        const sk = await getPrivateKey();
+        return finalizeEvent(event, sk);
+    }
+}
+
+// Encrypts an event in NIP-44 using NIP-07 if available, otherwise getPrivateKey()
+export const encrypt = async (json: object, user: object, receiverPK: string): string => {
+    if (await window.nostr.getPublicKey() === user.pubkey) {
+        return window.nostr.nip44.encrypt(
+            receiverPK, JSON.stringify(json));
+    } else {
+        const senderSK = await getPrivateKey();
+        const senderSKString = bytesToHex(senderSK);
+        const ckey = u.getConversationKey(senderSKString, receiverPK);
+        return libnip44.encrypt(JSON.stringify(json), ckey);
+    }
+}
+
+// Decrypts an event in NIP-44 using NIP-07 if available, otherwise getPrivateKey()
+export const decrypt = async (encrypted: string, user: object, receiverPK: string): object => {
+    if (await window.nostr.getPublicKey() === user.pubkey) {
+        return JSON.parse(await window.nostr.nip44.decrypt(
+            receiverPK, encrypted));
+    } else {
+        const senderSK = await getPrivateKey();
+        const senderSKString = bytesToHex(senderSK);
+        const ckey = u.getConversationKey(senderSKString, receiverPK);
+        return JSON.parse(libnip44.decrypt(encrypted, ckey));
+    }
+}
diff --git a/src/lib/nip11.ts b/src/lib/nip11.ts
new file mode 100644
index 00000000..af254b7e
--- /dev/null
+++ b/src/lib/nip11.ts
@@ -0,0 +1,15 @@
+import { fetchRelayInformation } from 'nostr-tools/nip11';
+
+// Accepts a list of relays, and returns a list of the relays that support all the provided NIPs.
+export const relaysSupporting = async (relays: string[], nips: number[]) => {
+    let supportingRelays = [];
+
+    for (const relay of relays) {
+        const relayInfo = await fetchRelayInformation(relay);
+        if (nips.every(relay => relayInfo.supported_nips.includes(relay))) {
+            supportingRelays.push(relay);
+        }
+    }
+
+    return supportingRelays;
+}
diff --git a/src/lib/nip17.ts b/src/lib/nip17.ts
new file mode 100644
index 00000000..b128dab9
--- /dev/null
+++ b/src/lib/nip17.ts
@@ -0,0 +1,223 @@
+import { bytesToHex } from '@noble/hashes/utils';
+
+import { finalizeEvent, getEventHash, generateSecretKey, getPublicKey } from 'nostr-tools/pure';
+import { SimplePool } from 'nostr-tools/pool';
+import { unwrapEvent } from 'nostr-tools/nip17';
+
+import { getPrivateKey } from '$lib/nostr';
+import { relaysSupporting } from '$lib/nip11';
+import { expired, expiration } from '$lib/nip40';
+import { encrypt, u } from '$lib/nip44';
+
+const TWO_DAYS = 2 * 24 * 60 * 60;
+const randomTimestamp = () => Math.floor(
+    Date.now() / 1000 - Math.random() * TWO_DAYS);
+const pool = new SimplePool();
+let relayListCache = new Map();
+
+import { PUBLIC_DM_RELAYS } from '$env/static/public';
+const DM_RELAYS_LIST = PUBLIC_DM_RELAYS.split(',');
+const DM_FETCH_LIMIT = 256;
+
+// Create a NIP-17 message using a provided sender secret key.
+// If wrapPK is specified and different than receiverPK,
+// the message will be gift-wrapped to wrapPK
+// but the rumour will be sent to receiverPK.
+// If expiryDays is specified, the message will expire in that many days,
+// plus a random amount from 0 to 2 for security.
+// (expiration time = random creation time + expiryDays + 2 days)
+export const createNIP17MessageSK = (text: string, senderSK: Uint8Array, receiverPK: string, wrapPK: string = null, expiryDays: number = null) => {
+    const rumour = createRumour(text, getPublicKey(senderSK), receiverPK);
+    const sealed = sealRumourSK(rumour, senderSK, wrapPK || receiverPK, expiryDays);
+    return giftWrap(sealed, wrapPK || receiverPK, expiryDays);
+}
+
+// Create a NIP-17 message using NIP-07, requiring no sender secret key.
+// If wrapPK is specified and different than receiverPK,
+// the message will be gift-wrapped to wrapPK
+// but the rumour will be sent to receiverPK.
+// If expiryDays is specified, the message will expire in that many days,
+// plus a random amount from 0 to 2 for security.
+// (expiration time = random creation time + expiryDays + 2 days)
+export const createNIP17MessageNIP07 = async (text: string, senderPK: string, receiverPK: string, wrapPK: string = null, expiryDays: number = null) => {
+    const rumour = createRumour(text, senderPK, receiverPK);
+    const sealed = await sealRumourNip07(rumour, wrapPK || receiverPK, expiryDays);
+    return giftWrap(sealed, wrapPK || receiverPK, expiryDays);
+}
+
+const createRumour = (text: string, senderPK: string, receiverPK: string) => {
+    const rumour = {
+        kind: 14, // rumour
+        created_at: Math.floor(Date.now() / 1000),
+        tags: [["p", receiverPK]],
+        pubkey: senderPK,
+        content: text
+    };
+    rumour.id = getEventHash(rumour); // do NOT sign rumours!
+    return rumour;
+}
+
+const sealRumourSK = (rumour: object, senderSK: Uint8Array, receiverPK: string, expiryDays: number = null) => {
+    const senderSKString = bytesToHex(senderSK);
+    const conversationKey = u.getConversationKey(senderSKString, receiverPK);
+    const encryptedRumour = encrypt(JSON.stringify(rumour), conversationKey);
+
+    const created = randomTimestamp();
+    const sealEvent = {
+        kind: 13, // seal
+        created_at: created,
+        tags: [],
+        pubkey: getPublicKey(senderSK),
+        content: encryptedRumour
+    }
+    if (expiryDays != null) {
+        const expiration = created + (expiryDays + 2) * 86400;
+        sealEvent.tags.push(["expiration", expiration.toString()]);
+    }
+
+    return finalizeEvent(sealEvent, senderSK);
+}
+
+const sealRumourNip07 = async (rumour: object, receiverPK: string, expiryDays: number = null) => {
+    const encryptedRumour = await window.nostr.nip44.encrypt(
+        receiverPK, JSON.stringify(rumour));
+
+    const created = randomTimestamp();
+    const sealEvent = {
+        kind: 13, // seal
+        created_at: created,
+        tags: [],
+        content: encryptedRumour
+    }
+    if (expiryDays != null) {
+        const expiration = created + (expiryDays + 2) * 86400;
+        sealEvent.tags.push(["expiration", expiration.toString()]);
+    }
+
+    return window.nostr.signEvent(sealEvent);
+}
+
+const giftWrap = (event: object, receiverPK: string, expiryDays: number = null) => {
+    const secretKey = generateSecretKey();
+    const SKString = bytesToHex(secretKey);
+    const conversationKey = u.getConversationKey(secretKey, receiverPK);
+    const encryptedEvent = encrypt(JSON.stringify(event), conversationKey);
+    const created = randomTimestamp();
+
+    const giftWrapEvent = {
+        kind: 1059, // gift wrap
+        created_at: created,
+        tags: [["p", receiverPK]],
+        pubkey: getPublicKey(secretKey),
+        content: encryptedEvent
+    }
+    if (expiryDays != null) {
+        const expiration = created + (expiryDays + 2) * 86400;
+        giftWrapEvent.tags.push(["expiration", expiration.toString()]);
+    }
+
+    return finalizeEvent(giftWrapEvent, secretKey);
+}
+
+const decryptNIP17MessageNIP07 = async (wrapped: object): object => {
+    const sealedText = await window.nostr.nip44.decrypt(
+        wrapped.pubkey, wrapped.content);
+    const sealed = JSON.parse(sealedText);
+    const rumourText = await window.nostr.nip44.decrypt(
+        sealed.pubkey, sealed.content);
+    return JSON.parse(rumourText);
+}
+
+// Decrypts the provided message, addressed to the user.
+// If NIP-07 is available, it uses that, otherwise it uses getPrivateKey().
+export const decrypt = async (wrapped: object, user: object): object => {
+   if (await window.nostr.getPublicKey() === user.pubkey) {
+     return decryptNIP17MessageNIP07(wrapped);
+   } else {
+     const sk = await getPrivateKey(user);
+     return unwrapEvent(wrapped, sk);
+   }
+ }
+
+// Returns the rumours of the messages the provided user has sent or received.
+// If the events have an expiration timestamp,
+// that timestamp is added to its rumour object as the property `expiration`.
+export const getMessageRumours = async (user: object): object[] => {
+    const relays = await getPreferredRelays(user.pubkey);
+    const wrapped = await pool.querySync(
+        relays, { kinds: [1059], "#p": [user.pubkey], limit: DM_FETCH_LIMIT }
+    );
+
+    let rumours = [];
+    // intentionally decrypting sequentially to avoid having a bunch of popups
+    for (event of wrapped) {
+        if (expired(event)) {
+            console.log("relay(s) contain expired event", event.id);
+            continue;
+        }
+
+        const rumour = await decrypt(event, user);
+
+        const expires = expiration(event);
+        if (expires) {
+            rumour.expiration = expires;
+        }
+
+        rumours.push(rumour);
+    }
+
+    return rumours;
+}
+
+// Returns the preferred relays of the user with the provided pubkey,
+// according to their kind-10050 event.
+export const getPreferredRelays = async (pubkey: string): string[] => {
+    if (relayListCache.has(pubkey))
+        return relayListCache.get(pubkey);
+
+    const events = await pool.querySync(
+        DM_RELAYS_LIST, { kinds: [10050], limit: 1, authors: [pubkey] }
+    );
+
+    let relays = [];
+    for (const event of events) {
+        for (const tag of event.tags) {
+            if (tag.length >= 2 && tag[0] == "relay") {
+                relays.push(tag[1]);
+            }
+        }
+    }
+
+    relayListCache.set(pubkey, relays);
+    return relays;
+}
+
+const publishToPreferred = async (event: object, pubkey: string, expiryEnabled: boolean): Promise<string> => {
+    let preferredRelays = await getPreferredRelays(pubkey);
+    if (expiryEnabled) {
+        preferredRelays = await relaysSupporting(preferredRelays, [40]);
+    }
+    return Promise.any(pool.publish(preferredRelays, event));
+}
+
+// Sends a NIP-17 message from `user` to `recipient`.
+// If expiryDays is set, messages will expire after that many days.
+export const send = async (message: string, user: object, recipient: object, expiryDays?: number) => {
+    let event1, event2;
+    if (await window.nostr.getPublicKey() === user.pubkey) {
+        event1 = await createNIP17MessageNIP07(
+            message, user.pubkey, recipient.pubkey, recipient.pubkey, expiryDays);
+        event2 = await createNIP17MessageNIP07(
+            message, user.pubkey, recipient.pubkey, user.pubkey, expiryDays);
+    } else {
+        const sk = await getPrivateKey(user);
+        event1 = createNIP17MessageSK(
+            message, sk, recipient.pubkey, recipient.pubkey, expiryDays);
+        event2 = createNIP17MessageSK(
+            message, sk, recipient.pubkey, user.pubkey, expiryDays);
+    }
+
+    const p1 = publishToPreferred(event1, recipient.pubkey, expiryDays != null);
+    const p2 = publishToPreferred(event2, user.pubkey, expiryDays != null);
+    return Promise.all([p1, p2]);
+}
diff --git a/src/lib/nip40.ts b/src/lib/nip40.ts
new file mode 100644
index 00000000..030fe0df
--- /dev/null
+++ b/src/lib/nip40.ts
@@ -0,0 +1,16 @@
+// Returns true if the message has an expiration in the past, false otherwise.
+export const expired = (event: object): boolean => {
+    const expiryTime = expiration(event);
+    return expiryTime !== null && Date.now() / 1000 >= expiryTime;
+}
+
+// Returns the provided event's expiration time, as a Unix ms integer.
+// If it has none, returns null.
+export const expiration = (event: object): number | null => {
+    for (const tag of event.tags) {
+        if (tag[0] == "expiration") {
+            return parseInt(tag[1]);
+        }
+    }
+    return null;
+}
diff --git a/src/lib/nip44.ts b/src/lib/nip44.ts
new file mode 100644
index 00000000..313d6f6b
--- /dev/null
+++ b/src/lib/nip44.ts
@@ -0,0 +1,135 @@
+// Copied from this public-domain code:
+// https://github.com/paulmillr/nip44/blob/main/javascript/index.ts
+// Modified slightly to deal with a dependency issue
+
+import { chacha20 } from '@noble/ciphers/chacha';
+import { equalBytes } from '@noble/ciphers/utils';
+import { secp256k1 } from '@noble/curves/secp256k1';
+import { extract as hkdf_extract, expand as hkdf_expand } from '@noble/hashes/hkdf';
+import { hmac } from '@noble/hashes/hmac';
+import { sha256 } from '@noble/hashes/sha256';
+import { concatBytes, randomBytes, utf8ToBytes } from '@noble/hashes/utils';
+import { base64 } from '@scure/base';
+
+declare const TextDecoder: any;
+
+const decoder = new TextDecoder();
+export const u = {
+  minPlaintextSize: 0x0001, // 1b msg => padded to 32b
+  maxPlaintextSize: 0xffff, // 65535 (64kb-1) => padded to 64kb
+
+  utf8Encode: utf8ToBytes,
+  utf8Decode(bytes: Uint8Array) {
+    return decoder.decode(bytes);
+  },
+
+  getConversationKey(privkeyA: string, pubkeyB: string): Uint8Array {
+    const sharedX = secp256k1.getSharedSecret(privkeyA, '02' + pubkeyB).subarray(1, 33);
+    return hkdf_extract(sha256, sharedX, 'nip44-v2');
+  },
+
+  getMessageKeys(conversationKey: Uint8Array, nonce: Uint8Array) {
+    // ensureBytes(conversationKey, 32);
+    // ensureBytes(nonce, 32);
+    const keys = hkdf_expand(sha256, conversationKey, nonce, 76);
+    return {
+      chacha_key: keys.subarray(0, 32),
+      chacha_nonce: keys.subarray(32, 44),
+      hmac_key: keys.subarray(44, 76),
+    };
+  },
+
+  calcPaddedLen(len: number): number {
+    if (!Number.isSafeInteger(len) || len < 1) throw new Error('expected positive integer');
+    if (len <= 32) return 32;
+    const nextPower = 1 << (Math.floor(Math.log2(len - 1)) + 1);
+    const chunk = nextPower <= 256 ? 32 : nextPower / 8;
+    return chunk * (Math.floor((len - 1) / chunk) + 1);
+  },
+
+  writeU16BE(num: number) {
+    if (!Number.isSafeInteger(num) || num < u.minPlaintextSize || num > u.maxPlaintextSize)
+      throw new Error('invalid plaintext size: must be between 1 and 65535 bytes');
+    const arr = new Uint8Array(2);
+    new DataView(arr.buffer).setUint16(0, num, false);
+    return arr;
+  },
+
+  pad(plaintext: string): Uint8Array {
+    const unpadded = u.utf8Encode(plaintext);
+    const unpaddedLen = unpadded.length;
+    const prefix = u.writeU16BE(unpaddedLen);
+    const suffix = new Uint8Array(u.calcPaddedLen(unpaddedLen) - unpaddedLen);
+    return concatBytes(prefix, unpadded, suffix);
+  },
+
+  unpad(padded: Uint8Array): string {
+    const unpaddedLen = new DataView(padded.buffer).getUint16(0);
+    const unpadded = padded.subarray(2, 2 + unpaddedLen);
+    if (
+      unpaddedLen < u.minPlaintextSize ||
+      unpaddedLen > u.maxPlaintextSize ||
+      unpadded.length !== unpaddedLen ||
+      padded.length !== 2 + u.calcPaddedLen(unpaddedLen)
+    )
+      throw new Error('invalid padding');
+    return u.utf8Decode(unpadded);
+  },
+
+  hmacAad(key: Uint8Array, message: Uint8Array, aad: Uint8Array) {
+    if (aad.length !== 32) throw new Error('AAD associated data must be 32 bytes');
+    const combined = concatBytes(aad, message);
+    return hmac(sha256, key, combined);
+  },
+
+  // metadata: always 65b (version: 1b, nonce: 32b, max: 32b)
+  // plaintext: 1b to 0xffff
+  // padded plaintext: 32b to 0xffff
+  // ciphertext: 32b+2 to 0xffff+2
+  // raw payload: 99 (65+32+2) to 65603 (65+0xffff+2)
+  // compressed payload (base64): 132b to 87472b
+  decodePayload(payload: string) {
+    if (typeof payload !== 'string') throw new Error('payload must be a valid string');
+    const plen = payload.length;
+    if (plen < 132 || plen > 87472) throw new Error('invalid payload length: ' + plen);
+    if (payload[0] === '#') throw new Error('unknown encryption version');
+    let data: Uint8Array;
+    try {
+      data = base64.decode(payload);
+    } catch (error) {
+      throw new Error('invalid base64: ' + (error as any).message);
+    }
+    const dlen = data.length;
+    if (dlen < 99 || dlen > 65603) throw new Error('invalid data length: ' + dlen);
+    const vers = data[0];
+    if (vers !== 2) throw new Error('unknown encryption version ' + vers);
+    return {
+      nonce: data.subarray(1, 33),
+      ciphertext: data.subarray(33, -32),
+      mac: data.subarray(-32),
+    };
+  },
+};
+
+export function encrypt(plaintext: string, conversationKey: Uint8Array, nonce = randomBytes(32)): string {
+  const { chacha_key, chacha_nonce, hmac_key } = u.getMessageKeys(conversationKey, nonce);
+  const padded = u.pad(plaintext);
+  const ciphertext = chacha20(chacha_key, chacha_nonce, padded);
+  const mac = u.hmacAad(hmac_key, ciphertext, nonce);
+  return base64.encode(concatBytes(new Uint8Array([2]), nonce, ciphertext, mac));
+}
+
+export function decrypt(payload: string, conversationKey: Uint8Array): string {
+  const { nonce, ciphertext, mac } = u.decodePayload(payload);
+  const { chacha_key, chacha_nonce, hmac_key } = u.getMessageKeys(conversationKey, nonce);
+  const calculatedMac = u.hmacAad(hmac_key, ciphertext, nonce);
+  if (!equalBytes(calculatedMac, mac)) throw new Error('invalid MAC');
+  const padded = chacha20(chacha_key, chacha_nonce, ciphertext);
+  return u.unpad(padded);
+}
+
+export const v2 = {
+  utils: u,
+  encrypt,
+  decrypt,
+};
diff --git a/src/lib/nip51.ts b/src/lib/nip51.ts
new file mode 100644
index 00000000..b1b0b613
--- /dev/null
+++ b/src/lib/nip51.ts
@@ -0,0 +1,71 @@
+import { SimplePool } from 'nostr-tools/pool';
+import { verifyEvent } from 'nostr-tools/pure';
+import { signEvent, encrypt, decrypt } from '$lib/nip07';
+const pool = new SimplePool();
+
+import { PUBLIC_DM_RELAYS } from '$env/static/public';
+const DM_RELAYS_LIST = PUBLIC_DM_RELAYS.split(',');
+
+// Mute the provided pubkey, as the provided user.
+export const mute = async (user: object, pubkey: string, hide: bool) => {
+    let { shown, hidden } = await getMuteLists(user);
+    if (hide) {
+        hidden.push(["p", pubkey]);
+    } else {
+        shown.push(["p", pubkey]);
+    }
+    await publishMuteList(user, shown, hidden);
+}
+
+const tagMatches = (tag: string[], pubkey: string): bool =>
+    tag.length >= 2 && tag[0] === "p" && tag[1] === pubkey;
+
+// Unmute the provided pubkey, as the provided user.
+export const unmute = async (user: object, pubkey: string) => {
+    let { shown, hidden } = await getMuteLists(user);
+    shown = shown.filter(tag => !tagMatches(tag, pubkey));
+    hidden = hidden.filter(tag => !tagMatches(tag, pubkey));
+    await publishMuteList(user, shown, hidden);
+}
+
+// Returns a set of the provided user's muted accounts.
+export const mutedAccounts = async (user: object): Set<string> => {
+    const { shown, hidden } = await getMuteLists(user);
+    let muted = new Set<string>();
+    for (const tag of shown) {
+        if (tag.length >= 2 && tag[0] === "p") {
+            muted.add(tag[1]);
+        }
+    }
+    for (const tag of hidden) {
+        if (tag.length >= 2 && tag[0] === "p") {
+            muted.add(tag[1]);
+        }
+    }
+    return muted;
+}
+
+const getMuteLists = async (user: object): object => {
+    const listEvents = await pool.querySync(
+        DM_RELAYS_LIST, { kinds: [10000], "authors": [user.pubkey], limit: 1 }
+    );
+    if (listEvents.length == 0) {
+        return { shown: [], hidden: [] };
+    }
+
+    return {
+        shown: listEvents[0].tags,
+        hidden: listEvents[0].content == "" ? [] :
+            await decrypt(listEvents[0].content, user, user.pubkey)
+    };
+}
+
+const publishMuteList = async (user: object, shown: string[], hidden: string[]) => {
+    const event = await signEvent({
+        kind: 10000,
+        created_at: Math.floor(Date.now() / 1000),
+        tags: shown,
+        content: await encrypt(hidden, user, user.pubkey)
+    }, user);
+    return Promise.any(pool.publish(DM_RELAYS_LIST, event));
+}
diff --git a/src/lib/nostr.ts b/src/lib/nostr.ts
index a22882bc..beebba02 100644
--- a/src/lib/nostr.ts
+++ b/src/lib/nostr.ts
@@ -210,3 +210,14 @@ const signingMethods = {
 		return signedEvent;
 	},
 };
+
+// Returns all the keys mentioned in the provided event's 'p' tags.
+export const pTagKeys = (event: object): string[] => {
+	let keys = [];
+	for (const tag of event.tags) {
+		if (tag[0] === "p") {
+			keys.push(tag[1]);
+		}
+	}
+	return keys;
+}