feat(nostr): Implemented 'Like' buttons functionality

src/components/app-body/nostr/feeds/feed-card.js

@@ -5,22 +5,87 @@
 import React, { useCallback, useEffect, useState } from 'react'
 import { Card, Spinner } from 'react-bootstrap'
 import { FontAwesomeIcon } from '@fortawesome/react-fontawesome'
-import { faUser } from '@fortawesome/free-solid-svg-icons'
+import { faUser, faHeart as faHeartSolid } from '@fortawesome/free-solid-svg-icons'
+import { faHeart } from '@fortawesome/free-regular-svg-icons'
 import * as nip19 from 'nostr-tools/nip19'
 import NostrFormat from '../nostr-format'
+import { finalizeEvent } from 'nostr-tools/pure'
+import { Relay } from 'nostr-tools/relay'
+import { hexToBytes } from '@noble/hashes/utils' // already an installed dependency
+import { RelayPool } from 'nostr'
 
 function FeedCard (props) {
   const { post, appData, profiles } = props
+  const { nostrKeyPair } = appData.bchWalletState
+
   const [profile, setProfile] = useState(profiles[post.pubkey])
 
   const [npub, setNpub] = useState('')
   const [isClicked, setIsClicked] = useState(false)
+  const [isLiked, setIsLiked] = useState(false)
+  const [likesCount, setLikesCount] = useState(null)
+  const [likesFetched, setLikesFetched] = useState(false)
 
+  // function to fetch a post likes reaction
+  const handleLikes = useCallback(async (post, userPubKey) => {
+    try {
+      const psf = 'wss://nostr-relay.psfoundation.info'
+      const res = await new Promise((resolve) => {
+        let likesCnt = 0
+        let userLikedCnt = 0
+        const pool = RelayPool([psf])
+        pool.on('open', relay => {
+          relay.subscribe('subid', { kinds: [7], '#e': [post.id] })
+        })
+
+        pool.on('eose', relay => {
+          relay.close()
+          resolve({
+            count: likesCnt,
+            userLiked: userLikedCnt > 0
+          })
+        })
+
+        pool.on('event', (relay, subId, ev) => {
+          try {
+            // Count likes
+            if (ev.content === '+') {
+              likesCnt++
+              // Count user likes
+              if (ev.pubkey === userPubKey) {
+                userLikedCnt++
+              }
+            }
+            // Count dislikes
+            if (ev.content === '-') {
+              likesCnt--
+              // Count user dislikes.
+              if (ev.pubkey === userPubKey) {
+                userLikedCnt--
+              }
+            }
+          } catch (error) {
+            // skip error
+          }
+        })
+      })
+      setLikesCount(res.count)
+      setIsLiked(res.userLiked)
+      setLikesFetched(true)
+    } catch (error) {
+      console.warn(error)
+    }
+  }, [])
   // Get npub from pubkey
   useEffect(() => {
     const npub = nip19.npubEncode(post.pubkey)
     setNpub(npub)
-  }, [post])
+
+    // Handle post likes
+    if (!likesFetched && nostrKeyPair.pubHex) {
+      handleLikes(post, nostrKeyPair.pubHex)
+    }
+  }, [post, nostrKeyPair, handleLikes, likesFetched])
 
   // Verify if pubkey profile exists into the profiles state
   useEffect(() => {
@@ -41,6 +106,58 @@ function FeedCard (props) {
     return npub.slice(0, 8) + '...' + npub.slice(-5)
   }, [])
 
+  const submitLike = async (e) => {
+    // Post on nostr network
+    e.preventDefault()
+    try {
+      const { nostrKeyPair } = appData.bchWalletState
+
+      setLikesFetched(false)
+      // Convert private key to binary
+      const privateKeyBin = hexToBytes(nostrKeyPair.privHex)
+
+      // Relay list
+      const psf = 'wss://nostr-relay.psfoundation.info'
+
+      // Define if like or dislike
+      let content = '+'
+      if (isLiked) { content = '-' }
+
+      // Generate a post.
+      const eventTemplate = {
+        kind: 7,
+        created_at: Math.floor(Date.now() / 1000),
+        tags: [
+          ['e', post.id, psf],
+          ['p', psf, nostrKeyPair.pubHex]
+        ],
+        content
+      }
+      console.log(`eventTemplate: ${JSON.stringify(eventTemplate, null, 2)}`)
+
+      // Sign the post
+      const signedEvent = finalizeEvent(eventTemplate, privateKeyBin)
+      console.log('signedEvent: ', signedEvent)
+
+      // Connect to a relay.
+      const relay = await Relay.connect(psf)
+      console.log(`connected to ${relay.url}`)
+
+      // Publish the message to the relay.
+      const result = await relay.publish(signedEvent)
+      console.log('result: ', result)
+
+      // Close the connection to the relay.
+      relay.close()
+
+      await handleLikes(post, nostrKeyPair.pubHex)
+      setLikesFetched(true)
+    } catch (error) {
+      console.warn(error)
+      setLikesFetched(true)
+    }
+  }
+
   return (
     <Card className='mb-4 bg-light rounded-4 shadow-sm border-0'>
       <Card.Body className='p-3'>
@@ -91,6 +208,50 @@ function FeedCard (props) {
             <NostrFormat content={post.content} />
           </div>
         </div>
+        <div className='d-flex justify-content-end'>
+          {likesFetched && (
+            <button
+              onClick={submitLike}
+              className='btn btn-link text-decoration-none p-0 d-flex align-items-center gap-2'
+              style={{
+                border: 'none',
+                background: 'transparent',
+                transition: 'all 0.2s ease',
+                color: isLiked ? '#e31b23' : '#536471',
+                fontSize: '14px',
+                fontWeight: '400'
+              }}
+              onMouseEnter={(e) => {
+                e.target.style.transform = 'scale(1.05)'
+              }}
+              onMouseLeave={(e) => {
+                e.target.style.transform = 'scale(1)'
+              }}
+            >
+              <FontAwesomeIcon
+                icon={isLiked ? faHeartSolid : faHeart}
+                style={{
+                  fontSize: '16px',
+                  color: isLiked ? '#e31b23' : '#536471',
+                  transition: 'all 0.2s ease'
+                }}
+              />
+              <span
+                style={{
+                  fontSize: '14px',
+                  fontWeight: '400',
+                  color: isLiked ? '#e31b23' : '#536471',
+                  transition: 'all 0.2s ease'
+                }}
+              >
+                {likesCount || 0}
+              </span>
+            </button>
+          )}
+          {!likesFetched && (
+            <Spinner animation='border' size='sm' className='ms-2' />
+          )}
+        </div>
       </Card.Body>
     </Card>