From f4c434a8031c50a5a908d68d3121b66971a1dfd8 Mon Sep 17 00:00:00 2001
From: Beh <github@beh.wtf>
Date: Sun, 6 Mar 2022 17:32:21 +0100
Subject: [PATCH] Add Fuzzy Select match highlighting

---
 src/prompts/fuzzy_select.rs | 18 +++++++-
 src/theme.rs                | 88 +++++++++++++++++++++++++++++++++++++
 2 files changed, 105 insertions(+), 1 deletion(-)

diff --git a/src/prompts/fuzzy_select.rs b/src/prompts/fuzzy_select.rs
index e17b4908..3f43f911 100644
--- a/src/prompts/fuzzy_select.rs
+++ b/src/prompts/fuzzy_select.rs
@@ -39,6 +39,7 @@ pub struct FuzzySelect<'a> {
     prompt: String,
     report: bool,
     clear: bool,
+    highlight_matches: bool,
     theme: &'a dyn Theme,
 }
 
@@ -101,6 +102,14 @@ impl FuzzySelect<'_> {
         self
     }
 
+    /// Indicates whether to highlight matched indices
+    ///
+    /// The default is to highlight the indices
+    pub fn highlight_matches(&mut self, val: bool) -> &mut Self {
+        self.highlight_matches = val;
+        self
+    }
+
     /// Enables user interaction and returns the result.
     ///
     /// The user can select the items using 'Enter' and the index of selected item will be returned.
@@ -180,7 +189,13 @@ impl FuzzySelect<'_> {
                 .skip(starting_row)
                 .take(visible_term_rows)
             {
-                render.select_prompt_item(item, idx == sel)?;
+                render.fuzzy_select_prompt_item(
+                    item,
+                    idx == sel,
+                    self.highlight_matches,
+                    &matcher,
+                    &search_term,
+                )?;
                 term.flush()?;
             }
 
@@ -276,6 +291,7 @@ impl<'a> FuzzySelect<'a> {
             prompt: "".into(),
             report: true,
             clear: true,
+            highlight_matches: true,
             theme,
         }
     }
diff --git a/src/theme.rs b/src/theme.rs
index 43ea7a01..fb814775 100644
--- a/src/theme.rs
+++ b/src/theme.rs
@@ -2,6 +2,8 @@
 use std::{fmt, io};
 
 use console::{style, Style, StyledObject, Term};
+#[cfg(feature = "fuzzy-select")]
+use fuzzy_matcher::{skim::SkimMatcherV2, FuzzyMatcher};
 
 /// Implements a theme for dialoguer.
 pub trait Theme {
@@ -206,6 +208,36 @@ pub trait Theme {
         )
     }
 
+    /// Formats a fuzzy select prompt item.
+    #[cfg(feature = "fuzzy-select")]
+    fn format_fuzzy_select_prompt_item(
+        &self,
+        f: &mut dyn fmt::Write,
+        text: &str,
+        active: bool,
+        highlight_matches: bool,
+        matcher: &SkimMatcherV2,
+        search_term: &str,
+    ) -> fmt::Result {
+        write!(f, "{} ", if active { ">" } else { " " })?;
+
+        if highlight_matches {
+            if let Some((_score, indices)) = matcher.fuzzy_indices(text, &search_term) {
+                for (idx, c) in text.chars().into_iter().enumerate() {
+                    if indices.contains(&idx) {
+                        write!(f, "{}", style(c).for_stderr().bold())?;
+                    } else {
+                        write!(f, "{}", c)?;
+                    }
+                }
+
+                return Ok(());
+            }
+        }
+
+        write!(f, "{}", text)
+    }
+
     /// Formats a fuzzy select prompt.
     #[cfg(feature = "fuzzy-select")]
     fn format_fuzzy_select_prompt(
@@ -277,6 +309,9 @@ pub struct ColorfulTheme {
     /// Formats the cursor for a fuzzy select prompt
     #[cfg(feature = "fuzzy-select")]
     pub fuzzy_cursor_style: Style,
+    // Formats the highlighting if matched characters
+    #[cfg(feature = "fuzzy-select")]
+    pub fuzzy_match_highlight_style: Style,
     /// Show the selections from certain prompts inline
     pub inline_selections: bool,
 }
@@ -304,6 +339,8 @@ impl Default for ColorfulTheme {
             unpicked_item_prefix: style(" ".to_string()).for_stderr(),
             #[cfg(feature = "fuzzy-select")]
             fuzzy_cursor_style: Style::new().for_stderr().black().on_white(),
+            #[cfg(feature = "fuzzy-select")]
+            fuzzy_match_highlight_style: Style::new().for_stderr().bold().yellow(),
             inline_selections: true,
         }
     }
@@ -577,6 +614,36 @@ impl Theme for ColorfulTheme {
         write!(f, "{} {}", details.0, details.1)
     }
 
+    /// Formats a fuzzy select prompt item.
+    #[cfg(feature = "fuzzy-select")]
+    fn format_fuzzy_select_prompt_item(
+        &self,
+        f: &mut dyn fmt::Write,
+        text: &str,
+        active: bool,
+        highlight_matches: bool,
+        matcher: &SkimMatcherV2,
+        search_term: &str,
+    ) -> fmt::Result {
+        write!(f, "{} ", if active { ">" } else { " " })?;
+
+        if highlight_matches {
+            if let Some((_score, indices)) = matcher.fuzzy_indices(text, &search_term) {
+                for (idx, c) in text.chars().into_iter().enumerate() {
+                    if indices.contains(&idx) {
+                        write!(f, "{}", self.fuzzy_match_highlight_style.apply_to(c))?;
+                    } else {
+                        write!(f, "{}", c)?;
+                    }
+                }
+
+                return Ok(());
+            }
+        }
+
+        write!(f, "{}", text)
+    }
+
     /// Formats a fuzzy-selectprompt after selection.
     #[cfg(feature = "fuzzy-select")]
     fn format_fuzzy_select_prompt(
@@ -775,6 +842,27 @@ impl<'a> TermThemeRenderer<'a> {
         })
     }
 
+    #[cfg(feature = "fuzzy-select")]
+    pub fn fuzzy_select_prompt_item(
+        &mut self,
+        text: &str,
+        active: bool,
+        highlight: bool,
+        matcher: &SkimMatcherV2,
+        search_term: &str,
+    ) -> io::Result<()> {
+        self.write_formatted_line(|this, buf| {
+            this.theme.format_fuzzy_select_prompt_item(
+                buf,
+                text,
+                active,
+                highlight,
+                matcher,
+                search_term,
+            )
+        })
+    }
+
     pub fn multi_select_prompt(
         &mut self,
         prompt: &str,