damus

UserSearch.swift (5284B)

---

 //
 //  UserSearch.swift
 //  damus
 //
 //  Created by William Casarin on 2023-01-28.
 //
 
 import SwiftUI
 
 struct UserSearch: View {
     let damus_state: DamusState
     let search: String
     @Binding var focusWordAttributes: (String?, NSRange?)
     @Binding var newCursorIndex: Int?
 
     @Binding var post: NSMutableAttributedString
     @EnvironmentObject var tagModel: TagModel
     
     var users: [Pubkey] {
         guard let txn = NdbTxn(ndb: damus_state.ndb) else { return [] }
         return search_profiles(profiles: damus_state.profiles, contacts: damus_state.contacts, search: search, txn: txn)
     }
     
     func on_user_tapped(pk: Pubkey) {
         let profile_txn = damus_state.profiles.lookup(id: pk)
         let profile = profile_txn?.unsafeUnownedValue
         let user_tag = user_tag_attr_string(profile: profile, pubkey: pk)
 
         appendUserTag(withTag: user_tag)
     }
 
     private func appendUserTag(withTag tag: NSMutableAttributedString) {
         guard let wordRange = focusWordAttributes.1 else { return }
 
         let appended = append_user_tag(tag: tag, post: post, word_range: wordRange)
         self.post = appended.post
 
         // adjust cursor position appropriately: ('diff' used in TextViewWrapper / updateUIView after below update of 'post')
         tagModel.diff = appended.tag.length - wordRange.length
 
         focusWordAttributes = (nil, nil)
         newCursorIndex = wordRange.location + appended.tag.length
     }
 
     var body: some View {
         VStack(spacing: 0) {
             Divider()
             ScrollView {
                 LazyVStack {
                     if users.count == 0 {
                         EmptyUserSearchView()
                     } else {
                         ForEach(users) { pk in
                             UserView(damus_state: damus_state, pubkey: pk)
                                 .contentShape(Rectangle())
                                 .onTapGesture {
                                     on_user_tapped(pk: pk)
                                 }
                         }
                     }
                 }
                 .padding()
             }
         }
     }
         
 }
 
 struct UserSearch_Previews: PreviewProvider {
     static let search: String = "jb55"
     @State static var post: NSMutableAttributedString = NSMutableAttributedString(string: "some @jb55")
     @State static var word: (String?, NSRange?) = (nil, nil)
     @State static var newCursorIndex: Int?
 
     static var previews: some View {
         UserSearch(damus_state: test_damus_state, search: search, focusWordAttributes: $word, newCursorIndex: $newCursorIndex, post: $post)
     }
 }
 
 /// Pad an attributed string: `@jb55` -> ` @jb55 `
 func pad_attr_string(tag: NSAttributedString, before: Bool = true) -> NSAttributedString {
     let new_tag = NSMutableAttributedString(string: "")
     if before {
         new_tag.append(.init(string: " "))
     }
 
     new_tag.append(tag)
     new_tag.append(.init(string: " "))
     return new_tag
 }
 
 /// Checks if whitespace precedes a tag. Useful to add spacing if we don't have it.
 func should_prepad_tag(tag: NSAttributedString, post: NSMutableAttributedString, word_range: NSRange) -> Bool {
     if word_range.location == 0 { // If the range starts at the very beginning of the post, there's nothing preceding it.
         return false
     }
 
     // Range for the character preceding the tag
     let precedingCharacterRange = NSRange(location: word_range.location - 1, length: 1)
 
     // Get the preceding character
     let precedingCharacter = post.attributedSubstring(from: precedingCharacterRange)
 
     guard let char = precedingCharacter.string.first else {
         return false
     }
 
     if char.isNewline {
         return false
     }
 
     // Check if the preceding character is a whitespace character
     return !char.isWhitespace
 }
 
 struct AppendedTag {
     let post: NSMutableAttributedString
     let tag: NSAttributedString
 }
 
 /// Appends a user tag (eg: @jb55) to a post. This handles adding additional padding as well.
 func append_user_tag(tag: NSAttributedString, post: NSMutableAttributedString, word_range: NSRange) -> AppendedTag {
     let new_post = NSMutableAttributedString(attributedString: post)
 
     // If we have a non-empty post and the last character is not whitespace, append a space
     // This prevents issues such as users typing cc@will and have it expand to ccnostr:bech32...
     let should_prepad = should_prepad_tag(tag: tag, post: post, word_range: word_range)
     let tag = pad_attr_string(tag: tag, before: should_prepad)
 
     new_post.replaceCharacters(in: word_range, with: tag)
 
     return AppendedTag(post: new_post, tag: tag)
 }
 
 /// Generate a mention attributed string, including the internal damus:nostr: link
 func user_tag_attr_string(profile: Profile?, pubkey: Pubkey) -> NSMutableAttributedString {
     let display_name = Profile.displayName(profile: profile, pubkey: pubkey)
     let name = display_name.username.truncate(maxLength: 50)
     let tagString = "@\(name)"
 
     return NSMutableAttributedString(string: tagString, attributes: [
         NSAttributedString.Key.font: UIFont.systemFont(ofSize: 18.0),
         NSAttributedString.Key.foregroundColor: UIColor.label,
         NSAttributedString.Key.link: "damus:nostr:\(pubkey.npub)"
     ])
 }