ui: add interactive prompts and typo suggestions

Signed-off-by: NotAShelf <raf@notashelf.dev>
Change-Id: Iec773550dca1f0ddc2f60360e6b7cb956a6a6964

src/ui_utils.rs

@@ -2,7 +2,7 @@
 
 use std::io;
 
-use dialoguer::{Confirm, MultiSelect, Select, theme::ColorfulTheme};
+use dialoguer::{Confirm, Input, MultiSelect, Select, theme::ColorfulTheme};
 
 /// Creates a terminal hyperlink using OSC 8 escape sequence
 /// Format: \x1b]8;;<URL>\x1b\\<TEXT>\x1b]8;;\x1b\\
@@ -58,6 +58,136 @@ pub fn curseforge_project_url(project_id: &str) -> String {
   format!("https://www.curseforge.com/minecraft/mc-mods/{project_id}")
 }
 
+/// Calculate Levenshtein edit distance between two strings
+#[allow(clippy::needless_range_loop)]
+fn levenshtein_distance(a: &str, b: &str) -> usize {
+  let a = a.to_lowercase();
+  let b = b.to_lowercase();
+  let a_len = a.chars().count();
+  let b_len = b.chars().count();
+
+  if a_len == 0 {
+    return b_len;
+  }
+  if b_len == 0 {
+    return a_len;
+  }
+
+  let mut matrix = vec![vec![0usize; b_len + 1]; a_len + 1];
+
+  for i in 0..=a_len {
+    matrix[i][0] = i;
+  }
+  for j in 0..=b_len {
+    matrix[0][j] = j;
+  }
+
+  let a_chars: Vec<char> = a.chars().collect();
+  let b_chars: Vec<char> = b.chars().collect();
+
+  for i in 1..=a_len {
+    for j in 1..=b_len {
+      let cost = usize::from(a_chars[i - 1] != b_chars[j - 1]);
+
+      matrix[i][j] = (matrix[i - 1][j] + 1) // deletion
+        .min(matrix[i][j - 1] + 1) // insertion
+        .min(matrix[i - 1][j - 1] + cost); // substitution
+    }
+  }
+
+  matrix[a_len][b_len]
+}
+
+/// Find similar strings to the input using Levenshtein distance.
+/// Returns suggestions sorted by similarity (most similar first).
+/// Only returns suggestions with distance <= `max_distance`.
+pub fn suggest_similar<'a>(
+  input: &str,
+  candidates: &'a [String],
+  max_distance: usize,
+) -> Vec<&'a str> {
+  let mut scored: Vec<(&str, usize)> = candidates
+    .iter()
+    .map(|c| (c.as_str(), levenshtein_distance(input, c)))
+    .filter(|(_, dist)| *dist <= max_distance && *dist > 0)
+    .collect();
+
+  scored.sort_by_key(|(_, dist)| *dist);
+  scored.into_iter().map(|(s, _)| s).collect()
+}
+
+/// Prompt user if they meant a similar project name.
+/// Returns `Some(suggested_name)` if user confirms, None otherwise.
+pub fn prompt_typo_suggestion(
+  input: &str,
+  candidates: &[String],
+) -> io::Result<Option<String>> {
+  // Use a max distance based on input length for reasonable suggestions
+  let max_distance = (input.len() / 2).clamp(2, 4);
+  let suggestions = suggest_similar(input, candidates, max_distance);
+
+  if let Some(first_suggestion) = suggestions.first()
+    && prompt_yes_no(&format!("Did you mean '{first_suggestion}'?"), true)?
+  {
+    return Ok(Some((*first_suggestion).to_string()));
+  }
+
+  Ok(None)
+}
+
+/// Prompt for text input with optional default value
+pub fn prompt_input(prompt: &str, default: Option<&str>) -> io::Result<String> {
+  let theme = ColorfulTheme::default();
+  let mut input = Input::<String>::with_theme(&theme).with_prompt(prompt);
+
+  if let Some(def) = default {
+    input = input.default(def.to_string());
+  }
+
+  input.interact_text().map_err(io::Error::other)
+}
+
+/// Prompt for text input, returning None if empty
+pub fn prompt_input_optional(prompt: &str) -> io::Result<Option<String>> {
+  let input: String = Input::with_theme(&ColorfulTheme::default())
+    .with_prompt(prompt)
+    .allow_empty(true)
+    .interact_text()
+    .map_err(io::Error::other)?;
+
+  if input.is_empty() {
+    Ok(None)
+  } else {
+    Ok(Some(input))
+  }
+}
+
+/// Prompt for `CurseForge` API key when authentication fails.
+/// Returns the API key if provided, None if cancelled.
+pub fn prompt_curseforge_api_key() -> io::Result<Option<String>> {
+  use dialoguer::Password;
+
+  println!();
+  println!("CurseForge API key is required but not configured.");
+  println!("Get your API key from: https://console.curseforge.com/");
+  println!();
+
+  if !prompt_yes_no("Would you like to enter your API key now?", true)? {
+    return Ok(None);
+  }
+
+  let key: String = Password::with_theme(&ColorfulTheme::default())
+    .with_prompt("CurseForge API key")
+    .interact()
+    .map_err(io::Error::other)?;
+
+  if key.is_empty() {
+    Ok(None)
+  } else {
+    Ok(Some(key))
+  }
+}
+
 #[cfg(test)]
 mod tests {
   use super::*;
@@ -74,4 +204,38 @@ mod tests {
     let url = modrinth_project_url("sodium");
     assert_eq!(url, "https://modrinth.com/mod/sodium");
   }
+
+  #[test]
+  fn test_levenshtein_distance() {
+    assert_eq!(levenshtein_distance("kitten", "sitting"), 3);
+    assert_eq!(levenshtein_distance("saturday", "sunday"), 3);
+    assert_eq!(levenshtein_distance("", "abc"), 3);
+    assert_eq!(levenshtein_distance("abc", ""), 3);
+    assert_eq!(levenshtein_distance("abc", "abc"), 0);
+    assert_eq!(levenshtein_distance("ABC", "abc"), 0); // case insensitive
+  }
+
+  #[test]
+  fn test_suggest_similar() {
+    let candidates = vec![
+      "sodium".to_string(),
+      "lithium".to_string(),
+      "phosphor".to_string(),
+      "iris".to_string(),
+      "fabric-api".to_string(),
+    ];
+
+    // Close typo should be suggested
+    let suggestions = suggest_similar("sodim", &candidates, 2);
+    assert!(!suggestions.is_empty());
+    assert_eq!(suggestions[0], "sodium");
+
+    // Complete mismatch should return empty
+    let suggestions = suggest_similar("xyz123", &candidates, 2);
+    assert!(suggestions.is_empty());
+
+    // Exact match returns empty (distance 0 filtered out)
+    let suggestions = suggest_similar("sodium", &candidates, 2);
+    assert!(suggestions.is_empty());
+  }
 }