From 44b7e07569edf6259a656166b203052400071bbe Mon Sep 17 00:00:00 2001
From: Pirmin Kalberer <pka@sourcepole.ch>
Date: Sun, 15 Sep 2019 23:05:13 +0200
Subject: [PATCH] Add Sublime style history search demo

---
 src/histsearch.rs | 171 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 171 insertions(+)
 create mode 100644 src/histsearch.rs

diff --git a/src/histsearch.rs b/src/histsearch.rs
new file mode 100644
index 0000000000..d5db186809
--- /dev/null
+++ b/src/histsearch.rs
@@ -0,0 +1,171 @@
+use ansi_term::Colour;
+use crossterm::{cursor, terminal, ClearType, InputEvent, KeyEvent, RawScreen};
+use std::io::Write;
+use sublime_fuzzy::best_match;
+
+fn select_from_list(lines: &Vec<&str>) {
+    const MAX_RESULTS: usize = 5;
+    #[derive(PartialEq)]
+    enum State {
+        Selecting,
+        Quit,
+        Selected(usize),
+        Edit(usize),
+    }
+    let mut state = State::Selecting;
+    if let Ok(_raw) = RawScreen::into_raw_mode() {
+        // User input for search
+        let mut searchinput = String::new();
+        let mut selected = 0;
+
+        let mut cursor = cursor();
+        let _ = cursor.hide();
+        let input = crossterm::input();
+        let mut sync_stdin = input.read_sync();
+
+        while state == State::Selecting {
+            let search_result = search(&searchinput, &lines, MAX_RESULTS);
+            let selected_lines: Vec<&str> = search_result
+                .iter()
+                .map(|item| &item.highlighted_text as &str)
+                .collect();
+            paint_selection_list(&selected_lines, selected);
+            if let Some(ev) = sync_stdin.next() {
+                match ev {
+                    InputEvent::Keyboard(k) => match k {
+                        KeyEvent::Esc | KeyEvent::Ctrl('c') => {
+                            state = State::Quit;
+                        }
+                        KeyEvent::Up => {
+                            if selected > 0 {
+                                selected -= 1;
+                            }
+                        }
+                        KeyEvent::Down => {
+                            if selected + 1 < selected_lines.len() {
+                                selected += 1;
+                            }
+                        }
+                        KeyEvent::Char('\n') => {
+                            state = State::Selected(search_result[selected].text_idx);
+                        }
+                        KeyEvent::Char('\t') | KeyEvent::Right => {
+                            state = State::Edit(search_result[selected].text_idx);
+                        }
+                        KeyEvent::Char(ch) => {
+                            searchinput.push(ch);
+                            selected = 0;
+                        }
+                        KeyEvent::Backspace => {
+                            searchinput.pop();
+                            selected = 0;
+                        }
+                        _ => {
+                            // println!("{}", format!("OTHER InputEvent: {:?}\n\n", k));
+                        }
+                    },
+                    _ => {}
+                }
+            }
+            cursor.move_up(selected_lines.len() as u16);
+        }
+        let (_x, y) = cursor.pos();
+        let _ = cursor.goto(0, y);
+        let _ = cursor.show();
+
+        let _ = RawScreen::disable_raw_mode();
+    }
+    let terminal = terminal();
+    terminal.clear(ClearType::FromCursorDown).unwrap();
+
+    match state {
+        State::Selected(idx) => {
+            print!("{}", lines[idx]);
+        }
+        State::Edit(idx) => {
+            print!("{}", lines[idx]);
+        }
+        _ => {}
+    }
+}
+
+struct Match {
+    highlighted_text: String,
+    text_idx: usize,
+}
+
+fn search(input: &String, lines: &Vec<&str>, max_results: usize) -> Vec<Match> {
+    if input.is_empty() {
+        return lines
+            .iter()
+            .take(max_results)
+            .enumerate()
+            .map(|(i, line)| Match {
+                highlighted_text: line.to_string(),
+                text_idx: i,
+            })
+            .collect();
+    }
+
+    let mut matches = lines
+        .iter()
+        .enumerate()
+        .map(|(idx, line)| (idx, best_match(&input, line)))
+        .filter(|(_i, m)| m.is_some())
+        .map(|(i, m)| (i, m.unwrap()))
+        .collect::<Vec<_>>();
+    matches.sort_by(|a, b| b.1.score().cmp(&a.1.score()));
+
+    let highlight = Colour::Cyan;
+    let results: Vec<Match> = matches
+        .iter()
+        .take(max_results)
+        .map(|(i, m)| {
+            let r = &lines[*i];
+            let mut outstr = String::with_capacity(r.len());
+            let mut idx = 0;
+            for (match_idx, len) in m.continuous_matches() {
+                outstr.push_str(&r[idx..match_idx]);
+                idx = match_idx + len;
+                outstr.push_str(&format!("{}", highlight.paint(&r[match_idx..idx])));
+            }
+            if idx < r.len() {
+                outstr.push_str(&r[idx..r.len()]);
+            }
+            Match {
+                highlighted_text: outstr,
+                text_idx: *i,
+            }
+        })
+        .collect();
+    results
+}
+
+fn paint_selection_list(lines: &Vec<&str>, selected: usize) {
+    let dimmed = Colour::White.dimmed();
+    let cursor = cursor();
+    let (_x, y) = cursor.pos();
+    for (i, line) in lines.iter().enumerate() {
+        let _ = cursor.goto(0, y + (i as u16));
+        if selected == i {
+            println!("{}", *line);
+        } else {
+            println!("{}", dimmed.paint(*line));
+        }
+    }
+    let _ = cursor.goto(0, y + (lines.len() as u16));
+    print!(
+        "{}",
+        Colour::Blue.paint("[ESC to quit, Enter to execute, Tab to edit]")
+    );
+
+    let _ = std::io::stdout().flush();
+    // Clear additional lines from previous selection
+    terminal().clear(ClearType::FromCursorDown).unwrap();
+}
+
+fn main() {
+    let hist = std::fs::read_to_string("history.txt").expect("Cannot open history.txt");
+    let lines = hist.lines().rev().collect();
+    select_from_list(&lines);
+}