fic(compatibility): htop scrolling issues (#77)

* fix(compatibility): scrolling inside scroll region with 'M' esc dispatch

* style(format): make rustfmt happy

* fix(tests): send proper data

* fix(logs): do not crash if log file doesn't exist

11 files changed, 179 insertions, 16 deletions

diff --git a/src/main.rs b/src/main.rs
index 96b50cb2..0f5fcf06 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -450,10 +450,11 @@ pub fn start(mut os_input: Box<dyn OsApi>, opts: Opt) {
     }
     // cleanup();
     let reset_style = "\u{1b}[m";
+    let show_cursor = "\u{1b}[?25h";
     let goto_start_of_last_line = format!("\u{1b}[{};{}H", full_screen_ws.rows, 1);
     let goodbye_message = format!(
-        "{}\n{}Bye from Mosaic!",
-        goto_start_of_last_line, reset_style
+        "{}\n{}{}Bye from Mosaic!",
+        goto_start_of_last_line, reset_style, show_cursor
     );
 
     os_input.unset_raw_mode(0);
diff --git a/src/pty_bus.rs b/src/pty_bus.rs
index 078e3271..3c8abcff 100644
--- a/src/pty_bus.rs
+++ b/src/pty_bus.rs
@@ -11,7 +11,7 @@ use std::path::PathBuf;
 
 use crate::layout::Layout;
 use crate::os_input_output::OsApi;
-use crate::utils::logging::debug_to_file;
+use crate::utils::logging::{debug_log_to_file, debug_to_file};
 use crate::ScreenInstruction;
 
 pub struct ReadFromPid {
diff --git a/src/terminal_pane/scroll.rs b/src/terminal_pane/scroll.rs
index 336c17bf..bfd6bd31 100644
--- a/src/terminal_pane/scroll.rs
+++ b/src/terminal_pane/scroll.rs
@@ -135,6 +135,28 @@ impl CanonicalLine {
 
         self.wrapped_fragments.truncate(fragment_index + 1);
     }
+    pub fn replace_with_empty_chars_before_cursor(
+        &mut self,
+        fragment_index: usize,
+        until_col: usize,
+        style_of_empty_space: CharacterStyles,
+    ) {
+        let mut empty_char_character = EMPTY_TERMINAL_CHARACTER;
+        empty_char_character.styles = style_of_empty_space;
+
+        if fragment_index > 0 {
+            for i in 0..(fragment_index - 1) {
+                let fragment = self.wrapped_fragments.get_mut(i).unwrap();
+                for i in 0..fragment.characters.len() {
+                    fragment.add_character(empty_char_character, i);
+                }
+            }
+        }
+        let current_fragment = self.wrapped_fragments.get_mut(fragment_index).unwrap();
+        for i in 0..until_col {
+            current_fragment.add_character(empty_char_character, i);
+        }
+    }
 }
 
 impl Debug for CanonicalLine {
@@ -331,21 +353,18 @@ impl Scroll {
     pub fn add_canonical_line(&mut self) {
         let current_canonical_line_index = self.cursor_position.line_index.0;
         if let Some((scroll_region_top, scroll_region_bottom)) = self.scroll_region {
-            // the scroll region indices start at 1, so we need to adjust them
             if self.show_cursor {
                 // scroll region should be ignored if the cursor is hidden
-                let scroll_region_top_index = scroll_region_top - 1;
-                let scroll_region_bottom_index = scroll_region_bottom - 1;
-                if current_canonical_line_index == scroll_region_bottom_index + 1 {
+                if current_canonical_line_index == scroll_region_bottom {
                     // end of scroll region
                     // when we have a scroll region set and we're at its bottom
                     // we need to delete its first line, thus shifting all lines in it upwards
                     // then we add an empty line at its end which will be filled by the application
                     // controlling the scroll region (presumably filled by whatever comes next in the
                     // scroll buffer, but that's not something we control)
-                    self.canonical_lines.remove(scroll_region_top_index);
+                    self.canonical_lines.remove(scroll_region_top);
                     self.canonical_lines
-                        .insert(scroll_region_bottom_index + 1, CanonicalLine::new());
+                        .insert(scroll_region_bottom, CanonicalLine::new());
                     return;
                 }
             }
@@ -473,6 +492,20 @@ impl Scroll {
             style_of_empty_space,
         );
     }
+    pub fn clear_canonical_line_left_of_cursor(&mut self, style_of_empty_space: CharacterStyles) {
+        let (current_canonical_line_index, current_line_wrap_position) =
+            self.cursor_position.line_index;
+        let current_cursor_column_position = self.cursor_position.column_index;
+        let current_canonical_line = self
+            .canonical_lines
+            .get_mut(current_canonical_line_index)
+            .expect("cursor out of bounds");
+        current_canonical_line.replace_with_empty_chars_before_cursor(
+            current_line_wrap_position,
+            current_cursor_column_position,
+            style_of_empty_space,
+        );
+    }
     pub fn clear_all_after_cursor(&mut self) {
         let (current_canonical_line_index, current_line_wrap_position) =
             self.cursor_position.line_index;
@@ -592,6 +625,25 @@ impl Scroll {
             }
         }
     }
+    pub fn move_cursor_up_in_scroll_region(&mut self, count: usize) {
+        if let Some((scroll_region_top, scroll_region_bottom)) = self.scroll_region {
+            // the scroll region indices start at 1, so we need to adjust them
+            for _ in 0..count {
+                let current_canonical_line_index = self.cursor_position.line_index.0;
+                if current_canonical_line_index == scroll_region_top {
+                    // if we're at the top line, we create a new line and remove the last line that
+                    // would otherwise overflow
+                    self.canonical_lines.remove(scroll_region_bottom);
+                    self.canonical_lines
+                        .insert(current_canonical_line_index, CanonicalLine::new());
+                } else if current_canonical_line_index > scroll_region_top
+                    && current_canonical_line_index <= scroll_region_bottom
+                {
+                    self.move_cursor_up(count);
+                }
+            }
+        }
+    }
     /// [scroll_up](https://github.com/alacritty/alacritty/blob/ec42b42ce601808070462111c0c28edb0e89babb/alacritty_terminal/src/grid/mod.rs#L261)
     /// This function takes the first line of the scroll region and moves it to the bottom (count times)
     pub fn rotate_scroll_region_up(&mut self, count: usize) {
diff --git a/src/terminal_pane/terminal_pane.rs b/src/terminal_pane/terminal_pane.rs
index 42062e24..73635b1f 100644
--- a/src/terminal_pane/terminal_pane.rs
+++ b/src/terminal_pane/terminal_pane.rs
@@ -687,8 +687,11 @@ impl vte::Perform for TerminalPane {
             if params[0] == 0 {
                 self.scroll
                     .clear_canonical_line_right_of_cursor(self.pending_styles);
+            } else if params[0] == 1 {
+                self.scroll
+                    .clear_canonical_line_left_of_cursor(self.pending_styles);
             }
-        // TODO: implement 1 and 2
+        // TODO: implement 2
         } else if c == 'J' {
             // clear all (0 => below, 1 => above, 2 => all, 3 => saved)
             if params[0] == 0 {
@@ -826,12 +829,21 @@ impl vte::Perform for TerminalPane {
             self.scroll.delete_lines_in_scroll_region(count);
             self.scroll.add_empty_lines_in_scroll_region(count);
         } else {
-            debug_log_to_file(format!("Unhandled csi: {}->{:?}", c, params)).unwrap();
-            panic!("unhandled csi: {}->{:?}", c, params);
+            let _ = debug_log_to_file(format!("Unhandled csi: {}->{:?}", c, params));
         }
     }
 
-    fn esc_dispatch(&mut self, _intermediates: &[u8], _ignore: bool, _byte: u8) {
-        // TBD
+    fn esc_dispatch(&mut self, intermediates: &[u8], _ignore: bool, byte: u8) {
+        match (byte, intermediates.get(0)) {
+            (b'M', None) => {
+                self.scroll.move_cursor_up_in_scroll_region(1);
+            }
+            _ => {
+                let _ = debug_log_to_file(format!(
+                    "Unhandled esc_dispatch: {}->{:?}",
+                    byte, intermediates
+                ));
+            }
+        }
     }
 }
diff --git a/src/tests/fixtures/htop_scrolling b/src/tests/fixtures/htop_scrolling
new file mode 100644
index 00000000..4e0df629
--- /dev/null
+++ b/src/tests/fixtures/htop_scrolling
diff --git a/src/tests/integration/compatibility.rs b/src/tests/integration/compatibility.rs
index c244f5bf..cb378ef5 100644
--- a/src/tests/integration/compatibility.rs
+++ b/src/tests/integration/compatibility.rs
@@ -214,3 +214,26 @@ pub fn htop() {
         assert_snapshot!(snapshot);
     }
 }
+
+#[test]
+pub fn htop_scrolling() {
+    let fake_win_size = PositionAndSize {
+        columns: 116,
+        rows: 28,
+        x: 0,
+        y: 0,
+    };
+    let fixture_name = "htop_scrolling";
+    let mut fake_input_output = get_fake_os_input(&fake_win_size, fixture_name);
+    fake_input_output.add_terminal_input(&[&COMMAND_TOGGLE, &COMMAND_TOGGLE, &QUIT]);
+    start(Box::new(fake_input_output.clone()), Opt::default());
+    let output_frames = fake_input_output
+        .stdout_writer
+        .output_frames
+        .lock()
+        .unwrap();
+    let snapshots = get_output_frame_snapshots(&output_frames, &fake_win_size);
+    for snapshot in snapshots {
+        assert_snapshot!(snapshot);
+    }
+}
diff --git a/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__htop-2.snap b/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__htop-2.snap
index 2fa4647b..3754cdd4 100644
--- a/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__htop-2.snap
+++ b/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__htop-2.snap
@@ -29,4 +29,4 @@ expression: snapshot
   99272 aram       20   0  8456  4348  3320 R  1.3  0.0  0:00.13 htop                                               
    8611 aram       20   0 2944M  318M  130M S  1.3  2.0  8:17.90 /usr/lib/firefox/firefox -contentproc -childID 6 -i
 F1Help  F2Setup F3SearchF4FilterF5Tree  F6SortByF7Nice -F8Nice +F9Kill  F10Quit                                     
-Bye from Mosaic!                                                                                                    
+Bye from Mosaic!█                                                                                                   
diff --git a/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__htop_scrolling-2.snap b/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__htop_scrolling-2.snap
new file mode 100644
index 00000000..c4f6568c
--- /dev/null
+++ b/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__htop_scrolling-2.snap
@@ -0,0 +1,32 @@
+---
+source: src/tests/integration/compatibility.rs
+expression: snapshot
+---
+  1  [||||||||||||||||||||||||||||||||||||||||||100.0%]   Tasks: 79, 382 thr; 1 running                             
+  2  [                                            0.0%]   Load average: 1.40 1.43 1.38                              
+  3  [                                            0.0%]   Uptime: 2 days, 07:33:50                                  
+  4  [                                            0.0%]                                                             
+  Mem[|||||||||||||||||||||||||||||||||||||3.64G/15.3G]                                                             
+  Swp[                                        0K/16.0G]                                                             
+                                                                                                                    
+    PID USER      PRI  NI  VIRT   RES   SHR S CPU% MEM%   TIME+  Command                                            
+ 123934 aram       20   0  8444  4384  3364 R 66.7  0.0  0:00.05 htop --delay=100000000000                          
+      1 root       20   0  171M 11616  8608 S  0.0  0.1  0:56.91 /sbin/init                                         
+    268 root       20   0 93324 34340 33072 S  0.0  0.2  0:01.05 /usr/lib/systemd/systemd-journald                  
+    276 root       20   0 32648 10192  7240 S  0.0  0.1  0:01.13 /usr/lib/systemd/systemd-udevd                     
+    286 root       20   0 78060  1132   996 S  0.0  0.0  0:00.00 /usr/bin/lvmetad -f                                
+    343 dbus       20   0  6952  4384  3520 S  0.0  0.0  0:13.85 /usr/bin/dbus-daemon --system --address=systemd: --
+    344 root       20   0 14588  7512  6176 S  0.0  0.0  0:03.21 /usr/bin/connmand -n --nodnsproxy                  
+    345 root       20   0 17696  8372  7128 S  0.0  0.1  0:00.67 /usr/lib/systemd/systemd-logind                    
+    395 root       20   0 1635M 83324 44976 S  0.0  0.5  0:32.43 /usr/bin/dockerd -H fd://                          
+    396 root       20   0 1635M 83324 44976 S  0.0  0.5  0:00.01 /usr/bin/dockerd -H fd://                          
+    397 root       20   0 1635M 83324 44976 S  0.0  0.5  0:00.01 /usr/bin/dockerd -H fd://                          
+    398 root       20   0 1635M 83324 44976 S  0.0  0.5  0:00.00 /usr/bin/dockerd -H fd://                          
+    399 root       20   0 1635M 83324 44976 S  0.0  0.5  0:00.00 /usr/bin/dockerd -H fd://                          
+    412 root       20   0 1635M 83324 44976 S  0.0  0.5  0:00.00 /usr/bin/dockerd -H fd://                          
+    441 root       20   0 1635M 83324 44976 S  0.0  0.5  0:41.35 /usr/bin/dockerd -H fd://                          
+    442 root       20   0 1635M 83324 44976 S  0.0  0.5  0:33.61 /usr/bin/dockerd -H fd://                          
+    444 root       20   0 1635M 83324 44976 S  0.0  0.5  0:33.13 /usr/bin/dockerd -H fd://                          
+    449 root       20   0 1635M 83324 44976 S  0.0  0.5  0:41.39 /usr/bin/dockerd -H fd://                          
+F1Help  F2Setup F3SearchF4FilterF5Tree  F6SortByF7Nice -F8Nice +F9Kill  F10Quit                                     
+Bye from Mosaic!█                                                                                                   
diff --git a/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__htop_scrolling.snap b/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__htop_scrolling.snap
new file mode 100644
index 00000000..fdf6cf89
--- /dev/null
+++ b/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__htop_scrolling.snap
@@ -0,0 +1,32 @@
+---
+source: src/tests/integration/compatibility.rs
+expression: snapshot
+---
+  1  [||||||||||||||||||||||||||||||||||||||||||100.0%]   Tasks: 79, 382 thr; 1 running                             
+  2  [                                            0.0%]   Load average: 1.40 1.43 1.38                              
+  3  [                                            0.0%]   Uptime: 2 days, 07:33:50                                  
+  4  [                                            0.0%]                                                             
+  Mem[|||||||||||||||||||||||||||||||||||||3.64G/15.3G]                                                             
+  Swp[                                        0K/16.0G]                                                             
+                                                                                                                    
+    PID USER      PRI  NI  VIRT   RES   SHR S CPU% MEM%   TIME+  Command                                            
+ 123934 aram       20   0  8444  4384  3364 R 66.7  0.0  0:00.05 htop --delay=100000000000                          
+      1 root       20   0  171M 11616  8608 S  0.0  0.1  0:56.91 /sbin/init                                         
+    268 root       20   0 93324 34340 33072 S  0.0  0.2  0:01.05 /usr/lib/systemd/systemd-journald                  
+    276 root       20   0 32648 10192  7240 S  0.0  0.1  0:01.13 /usr/lib/systemd/systemd-udevd                     
+    286 root       20   0 78060  1132   996 S  0.0  0.0  0:00.00 /usr/bin/lvmetad -f                                
+    343 dbus       20   0  6952  4384  3520 S  0.0  0.0  0:13.85 /usr/bin/dbus-daemon --system --address=systemd: --
+    344 root       20   0 14588  7512  6176 S  0.0  0.0  0:03.21 /usr/bin/connmand -n --nodnsproxy                  
+    345 root       20   0 17696  8372  7128 S  0.0  0.1  0:00.67 /usr/lib/systemd/systemd-logind                    
+    395 root       20   0 1635M 83324 44976 S  0.0  0.5  0:32.43 /usr/bin/dockerd -H fd://                          
+    396 root       20   0 1635M 83324 44976 S  0.0  0.5  0:00.01 /usr/bin/dockerd -H fd://                          
+    397 root       20   0 1635M 83324 44976 S  0.0  0.5  0:00.01 /usr/bin/dockerd -H fd://                          
+    398 root       20   0 1635M 83324 44976 S  0.0  0.5  0:00.00 /usr/bin/dockerd -H fd://                          
+    399 root       20   0 1635M 83324 44976 S  0.0  0.5  0:00.00 /usr/bin/dockerd -H fd://                          
+    412 root       20   0 1635M 83324 44976 S  0.0  0.5  0:00.00 /usr/bin/dockerd -H fd://                          
+    441 root       20   0 1635M 83324 44976 S  0.0  0.5  0:41.35 /usr/bin/dockerd -H fd://                          
+    442 root       20   0 1635M 83324 44976 S  0.0  0.5  0:33.61 /usr/bin/dockerd -H fd://                          
+    444 root       20   0 1635M 83324 44976 S  0.0  0.5  0:33.13 /usr/bin/dockerd -H fd://                          
+    449 root       20   0 1635M 83324 44976 S  0.0  0.5  0:41.39 /usr/bin/dockerd -H fd://                          
+F1Help  F2Setup F3SearchF4FilterF5Tree  F6SortByF7Nice -F8Nice +F9Kill  F10Quit                                     
+█                                                                                                                   
diff --git a/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__run_bandwhich_from_fish_shell-2.snap b/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__run_bandwhich_from_fish_shell-2.snap
index 8ca0fe37..9c90df81 100644
--- a/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__run_bandwhich_from_fish_shell-2.snap
+++ b/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__run_bandwhich_from_fish_shell-2.snap
@@ -29,4 +29,4 @@ expression: snapshot
 │                                                                                                                  │
 └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
  Press <SPACE> to pause. Use <TAB> to rearrange tables. (DNS queries hidden).                                       
-Bye from Mosaic!                                                                                                    
+Bye from Mosaic!█                                                                                                   
diff --git a/src/utils/logging.rs b/src/utils/logging.rs
index 1af1cb06..e175050e 100644
--- a/src/utils/logging.rs
+++ b/src/utils/logging.rs
@@ -33,6 +33,17 @@ pub fn debug_log_to_file(message: String) -> io::Result<()> {
     file.write_all(b"\n")
 }
 
+pub fn debug_log_to_file_without_newline(message: String) -> io::Result<()> {
+    atomic_create_file(MOSAIC_TMP_LOG_FILE);
+    let mut file = fs::OpenOptions::new()
+        .append(true)
+        .create(true)
+        .open(MOSAIC_TMP_LOG_FILE)?;
+    file.write_all(message.as_bytes())?;
+
+    Ok(())
+}
+
 pub fn debug_log_to_file_pid_0(message: String, pid: RawFd) -> io::Result<()> {
     if pid == 0 {
         debug_log_to_file(message)