dynamic subtopics

src/lib/discussion-topics.ts

@@ -0,0 +1,160 @@
+import { HASHTAG_REGEX } from '@/constants'
+import { NostrEvent } from 'nostr-tools'
+
+/**
+ * Normalize a topic string to lowercase with hyphens, no spaces
+ */
+export function normalizeTopic(topic: string): string {
+  return topic
+    .toLowerCase()
+    .replace(/\s+/g, '-')
+    .replace(/[^a-z0-9-]/g, '')
+    .replace(/-+/g, '-')
+    .replace(/^-|-$/g, '')
+}
+
+/**
+ * Extract hashtags from content
+ */
+export function extractHashtagsFromContent(content: string): string[] {
+  const matches = content.matchAll(HASHTAG_REGEX)
+  const hashtags: string[] = []
+  
+  for (const match of matches) {
+    // Remove the # prefix and normalize
+    const tag = match[0].substring(1)
+    hashtags.push(normalizeTopic(tag))
+  }
+  
+  return hashtags
+}
+
+/**
+ * Extract t-tags from event tags
+ */
+export function extractTTagsFromEvent(event: NostrEvent): string[] {
+  return event.tags
+    .filter(tag => tag[0] === 't' && tag[1])
+    .map(tag => normalizeTopic(tag[1]))
+}
+
+/**
+ * Extract all topics (both hashtags and t-tags) from an event
+ */
+export function extractAllTopics(event: NostrEvent): string[] {
+  const hashtags = extractHashtagsFromContent(event.content)
+  const tTags = extractTTagsFromEvent(event)
+  
+  // Combine and deduplicate
+  const allTopics = [...new Set([...hashtags, ...tTags])]
+  
+  return allTopics
+}
+
+/**
+ * Group threads by their primary topic and collect subtopic statistics
+ */
+export interface TopicAnalysis {
+  primaryTopic: string
+  subtopics: Map<string, Set<string>> // subtopic -> set of npubs
+  threads: NostrEvent[]
+}
+
+export function analyzeThreadTopics(
+  threads: NostrEvent[],
+  availableTopicIds: string[]
+): Map<string, TopicAnalysis> {
+  const topicMap = new Map<string, TopicAnalysis>()
+  
+  for (const thread of threads) {
+    const allTopics = extractAllTopics(thread)
+    
+    // Find the primary topic (first match from available topics)
+    let primaryTopic = 'general'
+    for (const topic of allTopics) {
+      if (availableTopicIds.includes(topic)) {
+        primaryTopic = topic
+        break
+      }
+    }
+    
+    // Get or create topic analysis
+    if (!topicMap.has(primaryTopic)) {
+      topicMap.set(primaryTopic, {
+        primaryTopic,
+        subtopics: new Map(),
+        threads: []
+      })
+    }
+    
+    const analysis = topicMap.get(primaryTopic)!
+    analysis.threads.push(thread)
+    
+    // Track subtopics (all topics except the primary one and 'general'/'all')
+    const subtopics = allTopics.filter(
+      t => t !== primaryTopic && t !== 'general' && t !== 'all' && t !== 'all-topics'
+    )
+    
+    for (const subtopic of subtopics) {
+      if (!analysis.subtopics.has(subtopic)) {
+        analysis.subtopics.set(subtopic, new Set())
+      }
+      analysis.subtopics.get(subtopic)!.add(thread.pubkey)
+    }
+  }
+  
+  return topicMap
+}
+
+/**
+ * Get dynamic subtopics for a given main topic
+ * Returns subtopics that have been used by more than minNpubs unique npubs
+ */
+export function getDynamicSubtopics(
+  analysis: TopicAnalysis | undefined,
+  minNpubs: number = 3
+): string[] {
+  if (!analysis) return []
+  
+  const subtopics: string[] = []
+  
+  for (const [subtopic, npubs] of analysis.subtopics.entries()) {
+    if (npubs.size >= minNpubs) {
+      subtopics.push(subtopic)
+    }
+  }
+  
+  // Sort alphabetically
+  return subtopics.sort()
+}
+
+/**
+ * Check if a thread matches a specific subtopic
+ */
+export function threadMatchesSubtopic(
+  thread: NostrEvent,
+  subtopic: string
+): boolean {
+  const allTopics = extractAllTopics(thread)
+  return allTopics.includes(subtopic)
+}
+
+/**
+ * Get the categorized topic for a thread
+ */
+export function getCategorizedTopic(
+  thread: NostrEvent,
+  availableTopicIds: string[]
+): string {
+  const allTopics = extractAllTopics(thread)
+  
+  // Find the first matching topic from available topics
+  for (const topic of allTopics) {
+    if (availableTopicIds.includes(topic)) {
+      return topic
+    }
+  }
+  
+  return 'general'
+}
+

src/pages/primary/DiscussionsPage/CreateThreadDialog.tsx

@@ -15,6 +15,7 @@ import { TDraftEvent } from '@/types'
 import { prefixNostrAddresses } from '@/lib/nostr-address'
 import { showPublishingError } from '@/lib/publishing-feedback'
 import dayjs from 'dayjs'
+import { extractHashtagsFromContent, normalizeTopic } from '@/lib/discussion-topics'
 
 // Utility functions for thread creation
 function extractImagesFromContent(content: string): string[] {
@@ -145,16 +146,30 @@ export default function CreateThreadDialog({
       // Extract images from processed content
       const images = extractImagesFromContent(processedContent)
       
+      // Extract hashtags from content
+      const hashtags = extractHashtagsFromContent(processedContent)
+      
       // Build tags array
       const tags = [
         ['title', title.trim()],
-        ['t', selectedTopic],
+        ['t', normalizeTopic(selectedTopic)],
         ['-'] // Required tag for relay privacy
       ]
       
+      // Add hashtags as t-tags (deduplicate with selectedTopic)
+      const uniqueHashtags = hashtags.filter(
+        hashtag => hashtag !== normalizeTopic(selectedTopic)
+      )
+      for (const hashtag of uniqueHashtags) {
+        tags.push(['t', hashtag])
+      }
+      
       // Add readings tags if this is a reading group
       if (isReadingGroup) {
+        // Only add if not already added from hashtags
+        if (!uniqueHashtags.includes('readings')) {
           tags.push(['t', 'readings'])
+        }
         tags.push(['author', author.trim()])
         tags.push(['subject', subject.trim()])
       }

src/pages/primary/DiscussionsPage/SubtopicFilter.tsx

@@ -0,0 +1,64 @@
+import { Button } from '@/components/ui/button'
+import { Badge } from '@/components/ui/badge'
+import { X } from 'lucide-react'
+import { useTranslation } from 'react-i18next'
+
+interface SubtopicFilterProps {
+  subtopics: string[]
+  selectedSubtopic: string | null
+  onSubtopicChange: (subtopic: string | null) => void
+}
+
+export default function SubtopicFilter({ 
+  subtopics, 
+  selectedSubtopic, 
+  onSubtopicChange 
+}: SubtopicFilterProps) {
+  const { t } = useTranslation()
+
+  if (subtopics.length === 0) return null
+
+  const formatSubtopicLabel = (subtopic: string): string => {
+    return subtopic
+      .split('-')
+      .map(word => word.charAt(0).toUpperCase() + word.slice(1))
+      .join(' ')
+  }
+
+  return (
+    <div className="flex gap-2 flex-wrap items-center">
+      <span className="text-sm text-muted-foreground">{t('Filter by')}:</span>
+      <Badge
+        variant={selectedSubtopic === null ? 'default' : 'outline'}
+        className="cursor-pointer"
+        onClick={() => onSubtopicChange(null)}
+      >
+        {t('All')}
+      </Badge>
+      {subtopics.map(subtopic => (
+        <Badge
+          key={subtopic}
+          variant={selectedSubtopic === subtopic ? 'default' : 'outline'}
+          className="cursor-pointer flex items-center gap-1"
+          onClick={() => onSubtopicChange(subtopic)}
+        >
+          {formatSubtopicLabel(subtopic)}
+          {selectedSubtopic === subtopic && (
+            <Button
+              variant="ghost"
+              size="icon"
+              className="h-3 w-3 p-0 hover:bg-transparent"
+              onClick={(e) => {
+                e.stopPropagation()
+                onSubtopicChange(null)
+              }}
+            >
+              <X className="h-2 w-2" />
+            </Button>
+          )}
+        </Badge>
+      ))}
+    </div>
+  )
+}
+

src/pages/primary/DiscussionsPage/index.tsx

@@ -7,18 +7,25 @@ import { useNostr } from '@/providers/NostrProvider'
 import { forwardRef, useEffect, useState, useCallback, useMemo } from 'react'
 import { useTranslation } from 'react-i18next'
 import PrimaryPageLayout from '@/layouts/PrimaryPageLayout'
-import { MessageSquarePlus, Book, BookOpen } from 'lucide-react'
+import { MessageSquarePlus, Book, BookOpen, Hash } from 'lucide-react'
 import ThreadCard from '@/pages/primary/DiscussionsPage/ThreadCard'
 import TopicFilter from '@/pages/primary/DiscussionsPage/TopicFilter'
 import ThreadSort, { SortOption } from '@/pages/primary/DiscussionsPage/ThreadSort'
 import CreateThreadDialog, { DISCUSSION_TOPICS } from '@/pages/primary/DiscussionsPage/CreateThreadDialog'
 import ViewToggle from '@/pages/primary/DiscussionsPage/ViewToggle'
+import SubtopicFilter from '@/pages/primary/DiscussionsPage/SubtopicFilter'
 import { NostrEvent } from 'nostr-tools'
 import client from '@/services/client.service'
 import noteStatsService from '@/services/note-stats.service'
 import { useSecondaryPage } from '@/PageManager'
 import { toNote } from '@/lib/link'
 import { kinds } from 'nostr-tools'
+import { 
+  analyzeThreadTopics, 
+  getCategorizedTopic, 
+  getDynamicSubtopics,
+  extractAllTopics
+} from '@/lib/discussion-topics'
 
 const DiscussionsPage = forwardRef((_, ref) => {
   const { t } = useTranslation()
@@ -42,6 +49,10 @@ const DiscussionsPage = forwardRef((_, ref) => {
   const [searchQuery, setSearchQuery] = useState('')
   const [filterBy, setFilterBy] = useState<'author' | 'subject' | 'all'>('all')
   
+  // Topic analysis for dynamic subtopics
+  const [topicAnalysis, setTopicAnalysis] = useState<ReturnType<typeof analyzeThreadTopics>>(new Map())
+  const [availableSubtopics, setAvailableSubtopics] = useState<string[]>([])
+
   // Use DEFAULT_FAVORITE_RELAYS for logged-out users, or user's favorite relays for logged-in users
   const availableRelays = useMemo(() => 
     pubkey && favoriteRelays.length > 0 ? favoriteRelays : DEFAULT_FAVORITE_RELAYS,
@@ -156,6 +167,26 @@ const DiscussionsPage = forwardRef((_, ref) => {
     fetchAllThreads()
   }, [fetchAllThreads])
 
+  // Analyze topics whenever threads change
+  useEffect(() => {
+    if (allThreads.length > 0) {
+      const analysis = analyzeThreadTopics(allThreads, availableTopicIds)
+      setTopicAnalysis(analysis)
+    } else {
+      setTopicAnalysis(new Map())
+    }
+  }, [allThreads, availableTopicIds])
+
+  // Update available subtopics when topic analysis or selected topic changes
+  useEffect(() => {
+    if (selectedTopic && selectedTopic !== 'all') {
+      const subtopics = getDynamicSubtopics(topicAnalysis.get(selectedTopic), 3)
+      setAvailableSubtopics(subtopics)
+    } else {
+      setAvailableSubtopics([])
+    }
+  }, [topicAnalysis, selectedTopic])
+
   useEffect(() => {
     // Only wait for stats for vote-based sorting
     if ((selectedSort === 'top' || selectedSort === 'controversial') && !statsLoaded) {
@@ -213,30 +244,20 @@ const DiscussionsPage = forwardRef((_, ref) => {
 
   const filterThreadsByTopic = useCallback(() => {
     const categorizedThreads = allThreads.map(thread => {
-      // Find all 't' tags in the thread
+      // Use new function to get categorized topic (considers both hashtags and t-tags)
-      const topicTags = thread.tags.filter(tag => tag[0] === 't' && tag[1])
+      const matchedTopic = getCategorizedTopic(thread, availableTopicIds)
       
-      // Find the first matching topic from our available topics
+      // Get all topics (hashtags + t-tags) for this thread
-      let matchedTopic = 'general' // Default to general
+      const allTopics = extractAllTopics(thread)
-      let isReadingGroup = false
       
-      for (const topicTag of topicTags) {
+      // Check if this is a reading group thread (special subtopic for literature)
-        if (availableTopicIds.includes(topicTag[1])) {
+      const isReadingGroup = allTopics.includes('readings')
-          matchedTopic = topicTag[1]
-          break // Use the first match found
-        }
-      }
-      
-      // Check if this is a reading group thread
-      if (matchedTopic === 'literature') {
-        const readingsTag = thread.tags.find(tag => tag[0] === 't' && tag[1] === 'readings')
-        isReadingGroup = !!readingsTag
-      }
       
       return {
         ...thread,
         _categorizedTopic: matchedTopic,
-        _isReadingGroup: isReadingGroup
+        _isReadingGroup: isReadingGroup,
+        _allTopics: allTopics
       }
     })
 
@@ -244,27 +265,24 @@ const DiscussionsPage = forwardRef((_, ref) => {
     let threadsForTopic = selectedTopic === 'all' 
       ? categorizedThreads.map(thread => {
           // Remove the temporary categorization property but keep relay source
-          const { _categorizedTopic, _isReadingGroup, ...cleanThread } = thread
+          const { _categorizedTopic, _isReadingGroup, _allTopics, ...cleanThread } = thread
           return cleanThread
         })
       : categorizedThreads
           .filter(thread => {
             if (thread._categorizedTopic !== selectedTopic) return false
             
-            // Handle subtopic filtering for literature
+            // Handle subtopic filtering
-            if (selectedTopic === 'literature' && selectedSubtopic) {
+            if (selectedSubtopic) {
-              if (selectedSubtopic === 'readings') {
+              // Check if thread matches the selected subtopic
-                return thread._isReadingGroup
+              return thread._allTopics.includes(selectedSubtopic)
-              } else if (selectedSubtopic === 'general') {
-                return !thread._isReadingGroup
-              }
             }
             
             return true
           })
           .map(thread => {
             // Remove the temporary categorization property but keep relay source
-            const { _categorizedTopic, _isReadingGroup, ...cleanThread } = thread
+            const { _categorizedTopic, _isReadingGroup, _allTopics, ...cleanThread } = thread
             return cleanThread
           })
 
@@ -357,7 +375,7 @@ const DiscussionsPage = forwardRef((_, ref) => {
           groups[topic] = []
         }
         // Remove the temporary categorization property but keep relay source
-        const { _categorizedTopic, ...cleanThread } = thread
+        const { _categorizedTopic, _isReadingGroup, _allTopics, ...cleanThread } = thread
         groups[topic].push(cleanThread)
         return groups
       }, {} as Record<string, NostrEvent[]>)
@@ -525,23 +543,42 @@ const DiscussionsPage = forwardRef((_, ref) => {
           </div>
         </div>
 
+        {/* Subtopic filter */}
+        {selectedTopic !== 'all' && availableSubtopics.length > 0 && (
+          <SubtopicFilter
+            subtopics={availableSubtopics}
+            selectedSubtopic={selectedSubtopic}
+            onSubtopicChange={setSelectedSubtopic}
+          />
+        )}
+
         {loading ? (
           <div className="flex justify-center py-8">
             <div className="text-muted-foreground">{t('Loading threads...')}</div>
           </div>
-        ) : selectedTopic === 'literature' ? (
+        ) : selectedTopic !== 'all' && availableSubtopics.length > 0 && !selectedSubtopic ? (
           <div className="space-y-6">
-            {/* General Literature and Arts Section */}
+            {/* General section for the main topic (without subtopics) */}
             <div className="space-y-3">
               <div className="flex items-center gap-2 pb-2 border-b">
                 <BookOpen className="w-5 h-5 text-primary" />
-                <h2 className="text-lg font-semibold">{t('General Topics')}</h2>
+                <h2 className="text-lg font-semibold">{t('General')}</h2>
                 <span className="text-sm text-muted-foreground">
-                  ({threads.filter(thread => !thread.tags.find(tag => tag[0] === 't' && tag[1] === 'readings')).length} {threads.filter(thread => !thread.tags.find(tag => tag[0] === 't' && tag[1] === 'readings')).length === 1 ? t('thread') : t('threads')})
+                  ({threads.filter(thread => {
+                    const allTopics = extractAllTopics(thread)
+                    // Threads that don't have any of the available subtopics
+                    return !availableSubtopics.some(subtopic => allTopics.includes(subtopic))
+                  }).length} {threads.filter(thread => {
+                    const allTopics = extractAllTopics(thread)
+                    return !availableSubtopics.some(subtopic => allTopics.includes(subtopic))
+                  }).length === 1 ? t('thread') : t('threads')})
                 </span>
               </div>
               <div className="space-y-3">
-                {threads.filter(thread => !thread.tags.find(tag => tag[0] === 't' && tag[1] === 'readings')).map(thread => (
+                {threads.filter(thread => {
+                  const allTopics = extractAllTopics(thread)
+                  return !availableSubtopics.some(subtopic => allTopics.includes(subtopic))
+                }).map(thread => (
                   <ThreadCard
                     key={thread.id}
                     thread={thread}
@@ -553,17 +590,36 @@ const DiscussionsPage = forwardRef((_, ref) => {
               </div>
             </div>
 
-            {/* Readings Section */}
+            {/* Dynamic subtopics sections */}
-            <div className="space-y-3">
+            {availableSubtopics.map(subtopic => {
+              const subtopicThreads = threads.filter(thread => {
+                const allTopics = extractAllTopics(thread)
+                return allTopics.includes(subtopic)
+              })
+              
+              if (subtopicThreads.length === 0) return null
+              
+              // Special handling for 'readings' subtopic in literature
+              const isReadingsSubtopic = subtopic === 'readings' && selectedTopic === 'literature'
+              
+              return (
+                <div key={subtopic} className="space-y-3">
                   <div className="flex items-center gap-2 pb-2 border-b">
+                    {isReadingsSubtopic ? (
                       <Book className="w-5 h-5 text-primary" />
-                <h2 className="text-lg font-semibold">{t('Readings')}</h2>
+                    ) : (
+                      <Hash className="w-5 h-5 text-primary" />
+                    )}
+                    <h2 className="text-lg font-semibold">
+                      {subtopic.split('-').map(word => word.charAt(0).toUpperCase() + word.slice(1)).join(' ')}
+                    </h2>
                     <span className="text-sm text-muted-foreground">
-                  ({threads.filter(thread => thread.tags.find(tag => tag[0] === 't' && tag[1] === 'readings')).length} {threads.filter(thread => thread.tags.find(tag => tag[0] === 't' && tag[1] === 'readings')).length === 1 ? t('thread') : t('threads')})
+                      ({subtopicThreads.length} {subtopicThreads.length === 1 ? t('thread') : t('threads')})
                     </span>
                   </div>
                   
-              {/* Readings-specific search and filter */}
+                  {/* Special search/filter for readings subtopic */}
+                  {isReadingsSubtopic && (
                     <div className="flex gap-2 items-center p-3 bg-muted/30 rounded-lg">
                       <input
                         type="text"
@@ -582,12 +638,13 @@ const DiscussionsPage = forwardRef((_, ref) => {
                         <option value="subject">{t('Subject')}</option>
                       </select>
                     </div>
+                  )}
                   
                   <div className="space-y-3">
-                {threads
+                    {subtopicThreads
-                  .filter(thread => thread.tags.find(tag => tag[0] === 't' && tag[1] === 'readings'))
                       .filter(thread => {
-                    if (!searchQuery.trim()) return true
+                        // Apply search filter only for readings subtopic
+                        if (!isReadingsSubtopic || !searchQuery.trim()) return true
                         
                         const authorTag = thread.tags.find(tag => tag[0] === 'author')
                         const subjectTag = thread.tags.find(tag => tag[0] === 'subject')
@@ -615,6 +672,8 @@ const DiscussionsPage = forwardRef((_, ref) => {
                       ))}
                   </div>
                 </div>
+              )
+            })}
           </div>
         ) : (viewMode === 'grouped' && selectedTopic === 'all' ? 
           Object.keys(groupedThreads).length === 0 :