1 files changed, 93 insertions, 0 deletions

diff --git a/src/client/ui.rs b/src/client/ui.rs
index 6fc2f62..493f660 100644
--- a/src/client/ui.rs
+++ b/src/client/ui.rs
@@ -153,6 +153,94 @@ pub fn parse_bet_arg(raw: &str) -> Result<u64, String> {
     Ok(bet)
 }
 
+/// Number of terminal columns used by `text`.
+///
+/// This is a deliberately small approximation of `unicode-width`: it handles
+/// ASCII, Latin diacritics, combining marks, CJK, and the common emoji ranges
+/// without adding a dependency.
+pub fn display_width(text: &str) -> usize {
+    text.chars().map(char_width).sum()
+}
+
+fn char_width(c: char) -> usize {
+    let cp = c as u32;
+    if cp < 0x20 || cp == 0x7F {
+        return 0;
+    }
+    if is_zero_width(cp) || is_combining(cp) {
+        return 0;
+    }
+    if is_wide(cp) {
+        2
+    } else {
+        1
+    }
+}
+
+fn is_zero_width(cp: u32) -> bool {
+    matches!(
+        cp,
+        0x200B..=0x200F | 0xFE00..=0xFE0F | 0xFEFF | 0x1F3FB..=0x1F3FF
+    )
+}
+
+fn is_combining(cp: u32) -> bool {
+    matches!(
+        cp,
+        0x0300..=0x036F
+            | 0x1AB0..=0x1AFF
+            | 0x1DC0..=0x1DFF
+            | 0x20D0..=0x20FF
+            | 0xFE20..=0xFE2F
+    )
+}
+
+fn is_wide(cp: u32) -> bool {
+    matches!(
+        cp,
+        0x1100..=0x115F
+            | 0x2329..=0x232A
+            | 0x2E80..=0xA4CF
+            | 0xAC00..=0xD7A3
+            | 0xF900..=0xFAFF
+            | 0xFE10..=0xFE19
+            | 0xFE30..=0xFE6F
+            | 0xFF00..=0xFF60
+            | 0xFFE0..=0xFFE6
+            | 0x1F300..=0x1F64F
+            | 0x1F680..=0x1F6FF
+            | 0x1F900..=0x1F9FF
+            | 0x20000..=0x3FFFD
+    )
+}
+
+/// The three lines printed on first contact with a host.
+pub fn first_contact_lines(addr: &str, fingerprint: &str) -> Vec<String> {
+    vec![
+        format!("First contact with {addr}: trusting a new certificate."),
+        format!("Fingerprint: {fingerprint}"),
+        "Future connections must present the same certificate key.".to_string(),
+    ]
+}
+
+/// Format remembered hosts so a 64-character fingerprint does not wrap on an
+/// 80-column terminal.
+pub fn host_lines(hosts: &[(String, Option<String>)]) -> Vec<String> {
+    if hosts.is_empty() {
+        return vec!["No remembered hosts.".to_string()];
+    }
+
+    let mut lines = vec!["Remembered hosts:".to_string()];
+    for (host, fingerprint) in hosts {
+        lines.push(format!("  {host}"));
+        match fingerprint {
+            Some(fingerprint) => lines.push(format!("  fingerprint: {fingerprint}")),
+            None => lines.push("  (no fingerprint)".to_string()),
+        }
+    }
+    lines
+}
+
 /// Lines to move the cursor up to reach the first line of a region that ends
 /// on the current line. `render()` has no trailing newline, so a 7-line board
 /// needs `MoveUp(6)`.
@@ -168,3 +256,8 @@ pub fn input_cursor_column(prompt_len: usize, input_len: usize) -> u16 {
         .saturating_add(input_len)
         .min(u16::MAX as usize) as u16
 }
+
+/// Format a ping round-trip time with one decimal place.
+pub fn format_pong(elapsed: std::time::Duration) -> String {
+    format!("Pong ({:.1}ms)", elapsed.as_secs_f64() * 1000.0)
+}