feat(helptext): communicate pause/resume to the user (#111)

* feat(helptext): communicate pause/resume to the user

* style(format): rustfmt

21 files changed, 70 insertions, 25 deletions

diff --git a/src/display/components/help_text.rs b/src/display/components/help_text.rs
new file mode 100644
index 0000000..49de3b8
--- /dev/null
+++ b/src/display/components/help_text.rs
@@ -0,0 +1,32 @@
+use ::tui::backend::Backend;
+use ::tui::layout::{Alignment, Rect};
+use ::tui::style::{Modifier, Style};
+use ::tui::terminal::Frame;
+use ::tui::widgets::{Paragraph, Text, Widget};
+
+pub struct HelpText {
+    pub paused: bool,
+}
+
+const TEXT_WHEN_PAUSED: &str = " Press <SPACE> to resume.";
+const TEXT_WHEN_NOT_PAUSED: &str = " Press <SPACE> to pause.";
+
+impl HelpText {
+    pub fn render(&self, frame: &mut Frame<impl Backend>, rect: Rect) {
+        let text = {
+            let content = if self.paused {
+                TEXT_WHEN_PAUSED
+            } else {
+                TEXT_WHEN_NOT_PAUSED
+            };
+
+            [Text::styled(
+                content,
+                Style::default().modifier(Modifier::BOLD),
+            )]
+        };
+        Paragraph::new(text.iter())
+            .alignment(Alignment::Left)
+            .render(frame, rect);
+    }
+}
diff --git a/src/display/components/layout.rs b/src/display/components/layout.rs
index e5ca069..9854e3c 100644
--- a/src/display/components/layout.rs
+++ b/src/display/components/layout.rs
@@ -2,6 +2,7 @@ use ::tui::backend::Backend;
 use ::tui::layout::{Constraint, Direction, Rect};
 use ::tui::terminal::Frame;
 
+use super::HelpText;
 use super::Table;
 use super::TotalBandwidth;
 
@@ -9,18 +10,26 @@ const FIRST_HEIGHT_BREAKPOINT: u16 = 30;
 const FIRST_WIDTH_BREAKPOINT: u16 = 120;
 const SECOND_WIDTH_BREAKPOINT: u16 = 150;
 
-fn leave_gap_on_top_of_rect(rect: Rect) -> Rect {
-    let app = ::tui::layout::Layout::default()
+fn top_app_and_bottom_split(rect: Rect) -> (Rect, Rect, Rect) {
+    let parts = ::tui::layout::Layout::default()
         .direction(Direction::Vertical)
         .margin(0)
-        .constraints([Constraint::Length(1), Constraint::Length(rect.height - 1)].as_ref())
+        .constraints(
+            [
+                Constraint::Length(1),
+                Constraint::Length(rect.height - 2),
+                Constraint::Length(1),
+            ]
+            .as_ref(),
+        )
         .split(rect);
-    app[1]
+    (parts[0], parts[1], parts[2])
 }
 
 pub struct Layout<'a> {
     pub header: TotalBandwidth<'a>,
     pub children: Vec<Table<'a>>,
+    pub footer: HelpText,
 }
 
 impl<'a> Layout<'a> {
@@ -52,7 +61,7 @@ impl<'a> Layout<'a> {
         }
     }
     pub fn render(&self, frame: &mut Frame<impl Backend>, rect: Rect) {
-        let app = leave_gap_on_top_of_rect(rect);
+        let (top, app, bottom) = top_app_and_bottom_split(rect);
         let layout_slots = self.build_layout(app);
         for i in 0..layout_slots.len() {
             if let Some(rect) = layout_slots.get(i) {
@@ -61,6 +70,7 @@ impl<'a> Layout<'a> {
                 }
             }
         }
-        self.header.render(frame, rect);
+        self.header.render(frame, top);
+        self.footer.render(frame, bottom);
     }
 }
diff --git a/src/display/components/mod.rs b/src/display/components/mod.rs
index a0e226d..c99596c 100644
--- a/src/display/components/mod.rs
+++ b/src/display/components/mod.rs
@@ -1,9 +1,11 @@
 mod display_bandwidth;
+mod help_text;
 mod layout;
 mod table;
 mod total_bandwidth;
 
 pub use display_bandwidth::*;
+pub use help_text::*;
 pub use layout::*;
 pub use table::*;
 pub use total_bandwidth::*;
diff --git a/src/display/components/total_bandwidth.rs b/src/display/components/total_bandwidth.rs
index ba78d2d..4a7ae9d 100644
--- a/src/display/components/total_bandwidth.rs
+++ b/src/display/components/total_bandwidth.rs
@@ -2,7 +2,7 @@ use ::tui::backend::Backend;
 use ::tui::layout::{Alignment, Rect};
 use ::tui::style::{Color, Modifier, Style};
 use ::tui::terminal::Frame;
-use ::tui::widgets::{Block, Borders, Paragraph, Text, Widget};
+use ::tui::widgets::{Paragraph, Text, Widget};
 
 use crate::display::{DisplayBandwidth, UIState};
 
@@ -32,7 +32,6 @@ impl<'a> TotalBandwidth<'a> {
             )]
         };
         Paragraph::new(title_text.iter())
-            .block(Block::default().borders(Borders::NONE))
             .alignment(Alignment::Left)
             .render(frame, rect);
     }
diff --git a/src/display/ui.rs b/src/display/ui.rs
index 49b6721..0c4d36a 100644
--- a/src/display/ui.rs
+++ b/src/display/ui.rs
@@ -3,7 +3,7 @@ use ::std::collections::HashMap;
 use ::tui::backend::Backend;
 use ::tui::Terminal;
 
-use crate::display::components::{Layout, Table, TotalBandwidth};
+use crate::display::components::{HelpText, Layout, Table, TotalBandwidth};
 use crate::display::UIState;
 use crate::network::{display_connection_string, display_ip_or_host, LocalSocket, Utilization};
 
@@ -87,9 +87,11 @@ where
                     state: &state,
                     paused,
                 };
+                let help_text = HelpText { paused };
                 let layout = Layout {
                     header: total_bandwidth,
                     children: vec![processes, connections, remote_addresses],
+                    footer: help_text,
                 };
                 layout.render(&mut frame, size);
             })
diff --git a/src/tests/cases/snapshots/ui__basic_startup.snap b/src/tests/cases/snapshots/ui__basic_startup.snap
index ec8d97c..baf94e1 100644
--- a/src/tests/cases/snapshots/ui__basic_startup.snap
+++ b/src/tests/cases/snapshots/ui__basic_startup.snap
@@ -50,6 +50,6 @@ expression: "&terminal_draw_events_mirror[0]"
 │                                                                                             ││                                                                                             │
 │                                                                                             ││                                                                                             │
 │                                                                                             ││                                                                                             │
-│                                                                                             ││                                                                                             │
 └─────────────────────────────────────────────────────────────────────────────────────────────┘└─────────────────────────────────────────────────────────────────────────────────────────────┘
+ Press <SPACE> to pause.                                                                                                                                                                      
 
diff --git a/src/tests/cases/snapshots/ui__bi_directional_traffic.snap b/src/tests/cases/snapshots/ui__bi_directional_traffic.snap
index ec8d97c..baf94e1 100644
--- a/src/tests/cases/snapshots/ui__bi_directional_traffic.snap
+++ b/src/tests/cases/snapshots/ui__bi_directional_traffic.snap
@@ -50,6 +50,6 @@ expression: "&terminal_draw_events_mirror[0]"
 │                                                                                             ││                                                                                             │
 │                                                                                             ││                                                                                             │
 │                                                                                             ││                                                                                             │
-│                                                                                             ││                                                                                             │
 └─────────────────────────────────────────────────────────────────────────────────────────────┘└─────────────────────────────────────────────────────────────────────────────────────────────┘
+ Press <SPACE> to pause.                                                                                                                                                                      
 
diff --git a/src/tests/cases/snapshots/ui__layout_full_width_under_30_height.snap b/src/tests/cases/snapshots/ui__layout_full_width_under_30_height.snap
index fe45202..2de98e8 100644
--- a/src/tests/cases/snapshots/ui__layout_full_width_under_30_height.snap
+++ b/src/tests/cases/snapshots/ui__layout_full_width_under_30_height.snap
@@ -29,6 +29,6 @@ expression: "&terminal_draw_events_mirror[0]"
 │                                                                                             ││                                                                                             │
 │                                                                                             ││                                                                                             │
 │                                                                                             ││                                                                                             │
-│                                                                                             ││                                                                                             │
 └─────────────────────────────────────────────────────────────────────────────────────────────┘└─────────────────────────────────────────────────────────────────────────────────────────────┘
+ Press <SPACE> to pause.                                                                                                                                                                      
 
diff --git a/src/tests/cases/snapshots/ui__layout_under_120_width_full_height.snap b/src/tests/cases/snapshots/ui__layout_under_120_width_full_height.snap
index bf9e509..678a313 100644
--- a/src/tests/cases/snapshots/ui__layout_under_120_width_full_height.snap
+++ b/src/tests/cases/snapshots/ui__layout_under_120_width_full_height.snap
@@ -50,6 +50,6 @@ expression: "&terminal_draw_events_mirror[0]"
 │                                                                                                                     │
 │                                                                                                                     │
 │                                                                                                                     │
-│                                                                                                                     │
 └─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+ Press <SPACE> to pause.                                                                                               
 
diff --git a/src/tests/cases/snapshots/ui__layout_under_120_width_under_30_height.snap b/src/tests/cases/snapshots/ui__layout_under_120_width_under_30_height.snap
index e312002..11de180 100644
--- a/src/tests/cases/snapshots/ui__layout_under_120_width_under_30_height.snap
+++ b/src/tests/cases/snapshots/ui__layout_under_120_width_under_30_height.snap
@@ -29,6 +29,6 @@ expression: "&terminal_draw_events_mirror[0]"
 │                                                                                                                     │
 │                                                                                                                     │
 │                                                                                                                     │
-│                                                                                                                     │
 └─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
+ Press <SPACE> to pause.                                                                                               
 
diff --git a/src/tests/cases/snapshots/ui__layout_under_150_width_full_height.snap b/src/tests/cases/snapshots/ui__layout_under_150_width_full_height.snap
index 43dc610..beaf97d 100644
--- a/src/tests/cases/snapshots/ui__layout_under_150_width_full_height.snap
+++ b/src/tests/cases/snapshots/ui__layout_under_150_width_full_height.snap
@@ -50,6 +50,6 @@ expression: "&terminal_draw_events_mirror[0]"
 │                                                                        ││                                                                         │
 │                                                                        ││                                                                         │
 │                                                                        ││                                                                         │
-│                                                                        ││                                                                         │
 └────────────────────────────────────────────────────────────────────────┘└─────────────────────────────────────────────────────────────────────────┘
+ Press <SPACE> to pause.                                                                                                                             
 
diff --git a/src/tests/cases/snapshots/ui__layout_under_150_width_under_30_height.snap b/src/tests/cases/snapshots/ui__layout_under_150_width_under_30_height.snap
index 9bd6846..8f8dc64 100644
--- a/src/tests/cases/snapshots/ui__layout_under_150_width_under_30_height.snap
+++ b/src/tests/cases/snapshots/ui__layout_under_150_width_under_30_height.snap
@@ -29,6 +29,6 @@ expression: "&terminal_draw_events_mirror[0]"
 │                                                                        ││                                                                         │
 │                                                                        ││                                                                         │
 │                                                                        ││                                                                         │
-│                                                                        ││                                                                         │
 └────────────────────────────────────────────────────────────────────────┘└─────────────────────────────────────────────────────────────────────────┘
+ Press <SPACE> to pause.                                                                                                                             
 
diff --git a/src/tests/cases/snapshots/ui__multiple_connections_from_remote_address.snap b/src/tests/cases/snapshots/ui__multiple_connections_from_remote_address.snap
index ec8d97c..baf94e1 100644
--- a/src/tests/cases/snapshots/ui__multiple_connections_from_remote_address.snap
+++ b/src/tests/cases/snapshots/ui__multiple_connections_from_remote_address.snap
@@ -50,6 +50,6 @@ expression: "&terminal_draw_events_mirror[0]"
 │                                                                                             ││                                                                                             │
 │                                                                                             ││                                                                                             │
 │                                                                                             ││                                                                                             │
-│                                                                                             ││                                                                                             │
 └─────────────────────────────────────────────────────────────────────────────────────────────┘└─────────────────────────────────────────────────────────────────────────────────────────────┘
+ Press <SPACE> to pause.                                                                                                                                                                      
 
diff --git a/src/tests/cases/snapshots/ui__multiple_packets_of_traffic_from_different_connections.snap b/src/tests/cases/snapshots/ui__multiple_packets_of_traffic_from_different_connections.snap
index ec8d97c..baf94e1 100644
--- a/src/tests/cases/snapshots/ui__multiple_packets_of_traffic_from_different_connections.snap
+++ b/src/tests/cases/snapshots/ui__multiple_packets_of_traffic_from_different_connections.snap
@@ -50,6 +50,6 @@ expression: "&terminal_draw_events_mirror[0]"
 │                                                                                             ││                                                                                             │
 │                                                                                             ││                                                                                             │
 │                                                                                             ││                                                                                             │
-│                                                                                             ││                                                                                             │
 └─────────────────────────────────────────────────────────────────────────────────────────────┘└─────────────────────────────────────────────────────────────────────────────────────────────┘
+ Press <SPACE> to pause.                                                                                                                                                                      
 
diff --git a/src/tests/cases/snapshots/ui__multiple_packets_of_traffic_from_single_connection.snap b/src/tests/cases/snapshots/ui__multiple_packets_of_traffic_from_single_connection.snap
index ec8d97c..baf94e1 100644
--- a/src/tests/cases/snapshots/ui__multiple_packets_of_traffic_from_single_connection.snap
+++ b/src/tests/cases/snapshots/ui__multiple_packets_of_traffic_from_single_connection.snap
@@ -50,6 +50,6 @@ expression: "&terminal_draw_events_mirror[0]"
 │                                                                                             ││                                                                                             │
 │                                                                                             ││                                                                                             │
 │                                                                                             ││                                                                                             │
-│                                                                                             ││                                                                                             │
 └─────────────────────────────────────────────────────────────────────────────────────────────┘└─────────────────────────────────────────────────────────────────────────────────────────────┘
+ Press <SPACE> to pause.                                                                                                                                                                      
 
diff --git a/src/tests/cases/snapshots/ui__multiple_processes_with_multiple_connections.snap b/src/tests/cases/snapshots/ui__multiple_processes_with_multiple_connections.snap
index ec8d97c..baf94e1 100644
--- a/src/tests/cases/snapshots/ui__multiple_processes_with_multiple_connections.snap
+++ b/src/tests/cases/snapshots/ui__multiple_processes_with_multiple_connections.snap
@@ -50,6 +50,6 @@ expression: "&terminal_draw_events_mirror[0]"
 │                                                                                             ││                                                                                             │
 │                                                                                             ││                                                                                             │
 │                                                                                             ││                                                                                             │
-│                                                                                             ││                                                                                             │
 └─────────────────────────────────────────────────────────────────────────────────────────────┘└─────────────────────────────────────────────────────────────────────────────────────────────┘
+ Press <SPACE> to pause.                                                                                                                                                                      
 
diff --git a/src/tests/cases/snapshots/ui__one_packet_of_traffic.snap b/src/tests/cases/snapshots/ui__one_packet_of_traffic.snap
index ec8d97c..baf94e1 100644
--- a/src/tests/cases/snapshots/ui__one_packet_of_traffic.snap
+++ b/src/tests/cases/snapshots/ui__one_packet_of_traffic.snap
@@ -50,6 +50,6 @@ expression: "&terminal_draw_events_mirror[0]"
 │                                                                                             ││                                                                                             │
 │                                                                                             ││                                                                                             │
 │                                                                                             ││                                                                                             │
-│                                                                                             ││                                                                                             │
 └─────────────────────────────────────────────────────────────────────────────────────────────┘└─────────────────────────────────────────────────────────────────────────────────────────────┘
+ Press <SPACE> to pause.                                                                                                                                                                      
 
diff --git a/src/tests/cases/snapshots/ui__one_process_with_multiple_connections.snap b/src/tests/cases/snapshots/ui__one_process_with_multiple_connections.snap
index ec8d97c..baf94e1 100644
--- a/src/tests/cases/snapshots/ui__one_process_with_multiple_connections.snap
+++ b/src/tests/cases/snapshots/ui__one_process_with_multiple_connections.snap
@@ -50,6 +50,6 @@ expression: "&terminal_draw_events_mirror[0]"
 │                                                                                             ││                                                                                             │
 │                                                                                             ││                                                                                             │
 │                                                                                             ││                                                                                             │
-│                                                                                             ││                                                                                             │
 └─────────────────────────────────────────────────────────────────────────────────────────────┘└─────────────────────────────────────────────────────────────────────────────────────────────┘
+ Press <SPACE> to pause.                                                                                                                                                                      
 
diff --git a/src/tests/cases/snapshots/ui__pause_by_space-2.snap b/src/tests/cases/snapshots/ui__pause_by_space-2.snap
index 204efd1..727e9cd 100644
--- a/src/tests/cases/snapshots/ui__pause_by_space-2.snap
+++ b/src/tests/cases/snapshots/ui__pause_by_space-2.snap
@@ -51,5 +51,5 @@ expression: "&terminal_draw_events_mirror[1]"
                                                                                                                                                                                               
                                                                                                                                                                                               
                                                                                                                                                                                               
-                                                                                                                                                                                              
+                  resume.                                                                                                                                                                     
 
diff --git a/src/tests/cases/snapshots/ui__pause_by_space.snap b/src/tests/cases/snapshots/ui__pause_by_space.snap
index ec8d97c..baf94e1 100644
--- a/src/tests/cases/snapshots/ui__pause_by_space.snap
+++ b/src/tests/cases/snapshots/ui__pause_by_space.snap
@@ -50,6 +50,6 @@ expression: "&terminal_draw_events_mirror[0]"
 │                                                                                             ││                                                                                             │
 │                                                                                             ││                                                                                             │
 │                                                                                             ││                                                                                             │
-│                                                                                             ││                                                                                             │
 └─────────────────────────────────────────────────────────────────────────────────────────────┘└─────────────────────────────────────────────────────────────────────────────────────────────┘
+ Press <SPACE> to pause.                                                                                                                                                                      
 
diff --git a/src/tests/cases/snapshots/ui__traffic_with_winch_event.snap b/src/tests/cases/snapshots/ui__traffic_with_winch_event.snap
index ec8d97c..baf94e1 100644
--- a/src/tests/cases/snapshots/ui__traffic_with_winch_event.snap
+++ b/src/tests/cases/snapshots/ui__traffic_with_winch_event.snap
@@ -50,6 +50,6 @@ expression: "&terminal_draw_events_mirror[0]"
 │                                                                                             ││                                                                                             │
 │                                                                                             ││                                                                                             │
 │                                                                                             ││                                                                                             │
-│                                                                                             ││                                                                                             │
 └─────────────────────────────────────────────────────────────────────────────────────────────┘└─────────────────────────────────────────────────────────────────────────────────────────────┘
+ Press <SPACE> to pause.