From 9b165e8f81a836c145581bce3658368d348995f5 Mon Sep 17 00:00:00 2001
From: Yves Biener <yves.biener@gmx.de>
Date: Wed, 6 Nov 2024 15:20:34 +0100
Subject: [PATCH] add/mod the following features

- split structure for better inclusions
- create PlainRenderer to render contents to the terminal
- simplify events
- clearify what structs are created on the heap and which are on the stack
- quit event is now emitted from the main event loop and not the input loop (see helper function `App.quit`)
- rename several variables and/or functions for easier understanding
- introduce `App.interrupt` to stop the input thread and start a new sub TUI which takes over the entire screen (i.e. 'hx', 'nvim', etc.)
---
 README.md              |   6 +-
 src/app.zig            |  73 +++++++++++---------
 src/event.zig          |   3 +-
 src/key.zig            | 149 +++++++++++++++++++++++++++++++++++++++++
 src/layout/Pane.zig    |   8 +++
 src/main.zig           |  38 +++++++----
 src/render.zig         |  48 +++++++++++++
 src/style.zig          |  23 +++++++
 src/terminal.zig       | 136 ++-----------------------------------
 src/widget/RawText.zig |  22 ++++--
 10 files changed, 320 insertions(+), 186 deletions(-)
 create mode 100644 src/key.zig
 create mode 100644 src/render.zig
 create mode 100644 src/style.zig

diff --git a/README.md b/README.md
index 24733a9..23d82ef 100644
--- a/README.md
+++ b/README.md
@@ -6,11 +6,6 @@ It contains information about me and my projects as well as blog entries about s
 
 ## Open tasks
 
-- [ ] BUG: when served via `wish-serve` the corresponding outputs are not pushed through the ssh connection
- - they are instead showed locally, which might cause issues with the docker container running in the background
- - very likely it is `tui-website` which causes this issue
- - not entirely as inputs are not passed through correctly to the below running application (i.e. `diffnav` via `serve git diff`)
- - fex however works as expected
 - [ ] Improve navigation
 - [ ] Have clickable/navigatable links inside of the tui application
 - [ ] Launch simple http server alongside tui application
@@ -20,3 +15,4 @@ It contains information about me and my projects as well as blog entries about s
 ## Branch: `own-tty-visuals`
 
 - [ ] How can I support to run a sub-process inside of a given pane / layout?
+- [ ] Create demo gifs using [vhs](https://github.com/charmbracelet/vhs)
diff --git a/src/app.zig b/src/app.zig
index 9bf0eb3..a1dc6a7 100644
--- a/src/app.zig
+++ b/src/app.zig
@@ -5,6 +5,7 @@ const terminal = @import("terminal.zig");
 const mergeTaggedUnions = @import("event.zig").mergeTaggedUnions;
 const isTaggedUnion = @import("event.zig").isTaggedUnion;
 
+const Key = @import("key.zig");
 const SystemEvent = @import("event.zig").SystemEvent;
 const Queue = @import("queue.zig").Queue;
 
@@ -24,53 +25,64 @@ pub fn App(comptime E: type) type {
 
         queue: Queue(Event, 256) = .{},
         thread: ?std.Thread = null,
-        quit: std.Thread.ResetEvent = .{},
+        quit_event: std.Thread.ResetEvent = .{},
         termios: ?std.posix.termios = null,
+        attached_handler: bool = false,
 
         pub const SignalHandler = struct {
             context: *anyopaque,
             callback: *const fn (context: *anyopaque) void,
         };
 
-        pub fn init() @This() {
-            var winch_act = std.posix.Sigaction{
-                .handler = .{ .handler = @This().handleWinch },
-                .mask = std.posix.empty_sigset,
-                .flags = 0,
-            };
-            std.posix.sigaction(std.posix.SIG.WINCH, &winch_act, null) catch @panic("could not attach signal WINCH");
-
-            return .{};
-        }
-
         pub fn start(this: *@This()) !void {
             if (this.thread) |_| return;
 
-            try registerWinch(.{
-                .context = this,
-                .callback = @This().winsizeCallback,
-            });
+            if (!this.attached_handler) {
+                var winch_act = std.posix.Sigaction{
+                    .handler = .{ .handler = @This().handleWinch },
+                    .mask = std.posix.empty_sigset,
+                    .flags = 0,
+                };
+                std.posix.sigaction(std.posix.SIG.WINCH, &winch_act, null) catch @panic("could not attach signal WINCH");
 
-            this.quit.reset();
+                try registerWinch(.{
+                    .context = this,
+                    .callback = @This().winsizeCallback,
+                });
+                this.attached_handler = true;
+            }
+
+            this.quit_event.reset();
             this.thread = try std.Thread.spawn(.{}, @This().run, .{this});
+            if (this.termios) |_| return;
+
             var termios: std.posix.termios = undefined;
             try terminal.enableRawMode(&termios);
             this.termios = termios;
             try terminal.saveScreen();
         }
 
-        pub fn stop(this: *@This()) !void {
-            if (this.termios) |*termios| {
-                try terminal.disableRawMode(termios);
-                try terminal.restoreScreen();
-            }
-            this.quit.set();
+        pub fn interrupt(this: *@This()) !void {
+            this.quit_event.set();
             if (this.thread) |thread| {
                 thread.join();
                 this.thread = null;
             }
         }
 
+        pub fn stop(this: *@This()) !void {
+            try this.interrupt();
+            if (this.termios) |*termios| {
+                try terminal.disableRawMode(termios);
+                try terminal.restoreScreen();
+            }
+        }
+
+        pub fn quit(this: *@This()) void {
+            this.quit_event.set();
+            this.postEvent(.quit);
+        }
+
         /// Returns the next available event, blocking until one is available.
         pub fn nextEvent(this: *@This()) Event {
             return this.queue.pop();
@@ -111,7 +123,7 @@ pub fn App(comptime E: type) type {
             var buf: [256]u8 = undefined;
             while (true) {
                 // FIX: I still think that there is a race condition (I'm just waiting 'long' enough)
-                this.quit.timedWait(20 * std.time.ns_per_ms) catch {
+                this.quit_event.timedWait(20 * std.time.ns_per_ms) catch {
                     const read_bytes = try terminal.read(buf[0..]);
                     // escape key presses
                     if (buf[0] == 0x1b and read_bytes > 1) {
@@ -121,17 +133,17 @@ pub fn App(comptime E: type) type {
                         }
                     } else {
                         const b = buf[0];
-                        const key: terminal.Key = switch (b) {
+                        const key: Key = switch (b) {
                             0x00 => .{ .cp = '@', .mod = .{ .ctrl = true } },
-                            0x08 => .{ .cp = terminal.Key.backspace },
-                            0x09 => .{ .cp = terminal.Key.tab },
-                            0x0a, 0x0d => .{ .cp = terminal.Key.enter },
+                            0x08 => .{ .cp = Key.backspace },
+                            0x09 => .{ .cp = Key.tab },
+                            0x0a, 0x0d => .{ .cp = Key.enter },
                             0x01...0x07, 0x0b...0x0c, 0x0e...0x1a => .{ .cp = b + 0x60, .mod = .{ .ctrl = true } },
                             0x1b => escape: {
                                 std.debug.assert(read_bytes == 1);
-                                break :escape .{ .cp = terminal.Key.escape };
+                                break :escape .{ .cp = Key.escape };
                             },
-                            0x7f => .{ .cp = terminal.Key.backspace },
+                            0x7f => .{ .cp = Key.backspace },
                             else => {
                                 var iter = terminal.code_point.Iterator{ .bytes = buf[0..read_bytes] };
                                 while (iter.next()) |cp| {
@@ -146,7 +158,6 @@ pub fn App(comptime E: type) type {
                 };
                 break;
             }
-            this.postEvent(.quit);
         }
     };
 }
diff --git a/src/event.zig b/src/event.zig
index 1f43013..60f76a9 100644
--- a/src/event.zig
+++ b/src/event.zig
@@ -2,6 +2,7 @@
 //! events. See `App` for more details about user defined events.
 const std = @import("std");
 const terminal = @import("terminal.zig");
+const Key = @import("key.zig");
 
 pub const Error = struct {
     err: anyerror,
@@ -13,7 +14,7 @@ pub const SystemEvent = union(enum) {
     quit,
     err: Error,
     resize: terminal.Size,
-    key: terminal.Key,
+    key: Key,
 };
 
 pub fn mergeTaggedUnions(comptime A: type, comptime B: type) type {
diff --git a/src/key.zig b/src/key.zig
new file mode 100644
index 0000000..eec5f8c
--- /dev/null
+++ b/src/key.zig
@@ -0,0 +1,149 @@
+//! Keybindings and Modifiers for user input detection and selection.
+const std = @import("std");
+
+pub const Modifier = struct {
+    shift: bool = false,
+    alt: bool = false,
+    ctrl: bool = false,
+};
+
+cp: u21,
+mod: Modifier = .{},
+
+/// Compare _this_ `Key` with an _other_ `Key`.
+///
+/// # Example
+///
+/// Configure `ctrl+c` to quit the application (done in main event loop of the application):
+///
+/// ```zig
+/// switch (event) {
+///     .quit => break,
+///     .key => |key| {
+///         // ctrl+c to quit
+///         if (terminal.Key.matches(key, .{ .cp = 'c', .mod = .{ .ctrl = true } })) {
+///             app.quit.set();
+///         }
+///     },
+///     else => {},
+/// }
+/// ```
+pub fn matches(this: @This(), other: @This()) bool {
+    return std.meta.eql(this, other);
+}
+
+// codepoints for keys
+pub const tab: u21 = 0x09;
+pub const enter: u21 = 0x0D;
+pub const escape: u21 = 0x1B;
+pub const space: u21 = 0x20;
+pub const backspace: u21 = 0x7F;
+
+// kitty key encodings (re-used here)
+pub const insert: u21 = 57348;
+pub const delete: u21 = 57349;
+pub const left: u21 = 57350;
+pub const right: u21 = 57351;
+pub const up: u21 = 57352;
+pub const down: u21 = 57353;
+pub const page_up: u21 = 57354;
+pub const page_down: u21 = 57355;
+pub const home: u21 = 57356;
+pub const end: u21 = 57357;
+pub const caps_lock: u21 = 57358;
+pub const scroll_lock: u21 = 57359;
+pub const num_lock: u21 = 57360;
+pub const print_screen: u21 = 57361;
+pub const pause: u21 = 57362;
+pub const menu: u21 = 57363;
+pub const f1: u21 = 57364;
+pub const f2: u21 = 57365;
+pub const f3: u21 = 57366;
+pub const f4: u21 = 57367;
+pub const f5: u21 = 57368;
+pub const f6: u21 = 57369;
+pub const f7: u21 = 57370;
+pub const f8: u21 = 57371;
+pub const f9: u21 = 57372;
+pub const f10: u21 = 57373;
+pub const f11: u21 = 57374;
+pub const f12: u21 = 57375;
+pub const f13: u21 = 57376;
+pub const f14: u21 = 57377;
+pub const f15: u21 = 57378;
+pub const @"f16": u21 = 57379;
+pub const f17: u21 = 57380;
+pub const f18: u21 = 57381;
+pub const f19: u21 = 57382;
+pub const f20: u21 = 57383;
+pub const f21: u21 = 57384;
+pub const f22: u21 = 57385;
+pub const f23: u21 = 57386;
+pub const f24: u21 = 57387;
+pub const f25: u21 = 57388;
+pub const f26: u21 = 57389;
+pub const f27: u21 = 57390;
+pub const f28: u21 = 57391;
+pub const f29: u21 = 57392;
+pub const f30: u21 = 57393;
+pub const f31: u21 = 57394;
+pub const @"f32": u21 = 57395;
+pub const f33: u21 = 57396;
+pub const f34: u21 = 57397;
+pub const f35: u21 = 57398;
+pub const kp_0: u21 = 57399;
+pub const kp_1: u21 = 57400;
+pub const kp_2: u21 = 57401;
+pub const kp_3: u21 = 57402;
+pub const kp_4: u21 = 57403;
+pub const kp_5: u21 = 57404;
+pub const kp_6: u21 = 57405;
+pub const kp_7: u21 = 57406;
+pub const kp_8: u21 = 57407;
+pub const kp_9: u21 = 57408;
+pub const kp_decimal: u21 = 57409;
+pub const kp_divide: u21 = 57410;
+pub const kp_multiply: u21 = 57411;
+pub const kp_subtract: u21 = 57412;
+pub const kp_add: u21 = 57413;
+pub const kp_enter: u21 = 57414;
+pub const kp_equal: u21 = 57415;
+pub const kp_separator: u21 = 57416;
+pub const kp_left: u21 = 57417;
+pub const kp_right: u21 = 57418;
+pub const kp_up: u21 = 57419;
+pub const kp_down: u21 = 57420;
+pub const kp_page_up: u21 = 57421;
+pub const kp_page_down: u21 = 57422;
+pub const kp_home: u21 = 57423;
+pub const kp_end: u21 = 57424;
+pub const kp_insert: u21 = 57425;
+pub const kp_delete: u21 = 57426;
+pub const kp_begin: u21 = 57427;
+pub const media_play: u21 = 57428;
+pub const media_pause: u21 = 57429;
+pub const media_play_pause: u21 = 57430;
+pub const media_reverse: u21 = 57431;
+pub const media_stop: u21 = 57432;
+pub const media_fast_forward: u21 = 57433;
+pub const media_rewind: u21 = 57434;
+pub const media_track_next: u21 = 57435;
+pub const media_track_previous: u21 = 57436;
+pub const media_record: u21 = 57437;
+pub const lower_volume: u21 = 57438;
+pub const raise_volume: u21 = 57439;
+pub const mute_volume: u21 = 57440;
+pub const left_shift: u21 = 57441;
+pub const left_control: u21 = 57442;
+pub const left_alt: u21 = 57443;
+pub const left_super: u21 = 57444;
+pub const left_hyper: u21 = 57445;
+pub const left_meta: u21 = 57446;
+pub const right_shift: u21 = 57447;
+pub const right_control: u21 = 57448;
+pub const right_alt: u21 = 57449;
+pub const right_super: u21 = 57450;
+pub const right_hyper: u21 = 57451;
+pub const right_meta: u21 = 57452;
+pub const iso_level_3_shift: u21 = 57453;
+pub const iso_level_5_shift: u21 = 57454;
diff --git a/src/layout/Pane.zig b/src/layout/Pane.zig
index d2a2950..aaed7fa 100644
--- a/src/layout/Pane.zig
+++ b/src/layout/Pane.zig
@@ -1,4 +1,5 @@
 const std = @import("std");
+const terminal = @import("../terminal.zig");
 const isTaggedUnion = @import("../event.zig").isTaggedUnion;
 const Error = @import("../event.zig").Error;
 
@@ -11,6 +12,7 @@ pub fn Layout(comptime Event: type) type {
         widget: Widget = undefined,
         events: std.ArrayList(Event) = undefined,
         c: std.ArrayList(u8) = undefined,
+        size: terminal.Size = undefined,
 
         pub fn init(allocator: std.mem.Allocator, widget: Widget) @This() {
             return .{
@@ -28,6 +30,12 @@ pub fn Layout(comptime Event: type) type {
         }
 
         pub fn handle(this: *@This(), event: Event) !*std.ArrayList(Event) {
+            switch (event) {
+                .resize => |size| {
+                    this.size = size;
+                },
+                else => {},
+            }
             this.events.clearRetainingCapacity();
             if (this.widget.handle(event)) |e| {
                 try this.events.append(e);
diff --git a/src/main.zig b/src/main.zig
index 5595e28..33c7821 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -3,6 +3,8 @@ const terminal = @import("terminal.zig");
 const zlog = @import("zlog");
 
 const App = @import("app.zig").App(union(enum) {});
+const Renderer = @import("render.zig").PlainRenderer();
+const Key = @import("key.zig");
 
 pub const std_options = zlog.std_options;
 const log = std.log.scoped(.default);
@@ -20,7 +22,8 @@ pub fn main() !void {
     }
     const allocator = gpa.allocator();
 
-    var app = App.init();
+    var app: App = .{};
+    var renderer: Renderer = .{};
 
     var rawText = App.Widget.RawText.init(allocator);
     const widget = App.Widget.createFrom(&rawText);
@@ -40,29 +43,36 @@ pub fn main() !void {
 
         switch (event) {
             .quit => break,
-            .resize => |size| {
-                // NOTE: draw actions should not happen here (still here for testing)
-                // NOTE: clearing the screen and positioning the cursor is only necessary for full screen applications
-                // - in-line applications should use relative movements instead and should only clear lines (which they draw)
-                // - in-line applications should not enter the alt screen
-                try terminal.clearScreen();
-                try terminal.setCursorPositionHome();
-                log.debug("Size := [x: {d}, y: {d}]", .{ size.cols, size.rows });
-            },
             .key => |key| {
-                log.debug("received key: {any}", .{key});
                 // ctrl+c to quit
-                if (terminal.Key.matches(key, .{ .cp = 'c', .mod = .{ .ctrl = true } })) {
-                    app.quit.set();
+                if (Key.matches(key, .{ .cp = 'c', .mod = .{ .ctrl = true } })) {
+                    app.quit();
                 }
+                if (Key.matches(key, .{ .cp = 'n', .mod = .{ .ctrl = true } })) {
+                    try app.interrupt();
+                    defer app.start() catch @panic("could not start app event loop");
+                    var child = std.process.Child.init(&.{"hx"}, allocator);
+                    _ = child.spawnAndWait() catch |err| {
+                        app.postEvent(.{
+                            .err = .{
+                                .err = err,
+                                .msg = "Spawning Helix failed",
+                            },
+                        });
+                    };
+                }
+            },
+            .err => |err| {
+                log.err("Received {any} with message: {s}", .{ err.err, err.msg });
             },
             else => {},
         }
+        // NOTE: this currently re-renders the screen for every key-press -> which might be a bit of an overkill
         const events = try layout.handle(event);
         for (events.items) |e| {
             app.postEvent(e);
         }
-        log.debug("Layout result: {s}", .{(try layout.content()).items});
+        try renderer.render(try layout.content());
     }
     // TODO: I could use the ascii codes in vaxis
     // - see https://gist.github.com/ConnerWill/d4b6c776b509add763e17f9f113fd25b
diff --git a/src/render.zig b/src/render.zig
new file mode 100644
index 0000000..b71dba3
--- /dev/null
+++ b/src/render.zig
@@ -0,0 +1,48 @@
+//! Renderer which holds the screen to compare with the previous screen for efficient rendering.
+const std = @import("std");
+const terminal = @import("terminal.zig");
+
+pub fn BufferedRenderer() type {
+    return struct {
+        refresh: bool = false,
+        size: terminal.Size = undefined,
+        screen: std.ArrayList(u8) = undefined,
+
+        pub fn init(allocator: std.mem.Allocator) @This() {
+            return .{
+                .screen = std.ArrayList(u8).init(allocator),
+            };
+        }
+
+        pub fn deinit(this: *@This()) void {
+            this.screen.deinit();
+            this.* = undefined;
+        }
+
+        pub fn resize(this: *@This(), size: terminal.Size) void {
+            // TODO: are there size changes which impact the corresponding rendered content?
+            // -> can I even be sure nothing needs to be re-rendered?
+            this.size = size;
+            this.refresh = true;
+        }
+
+        pub fn render(this: *@This(), content: *std.ArrayList(u8)) !void {
+            // TODO: put the corresponding screen to the terminal
+            // -> determine diff between screen and new content and only update the corresponding characters of the terminal
+            _ = this;
+            _ = content;
+            @panic("Not yet implemented.");
+        }
+    };
+}
+
+pub fn PlainRenderer() type {
+    return struct {
+        pub fn render(this: *@This(), content: *std.ArrayList(u8)) !void {
+            _ = this;
+            try terminal.clearScreen();
+            try terminal.setCursorPositionHome();
+            _ = try terminal.write(content.items);
+        }
+    };
+}
diff --git a/src/style.zig b/src/style.zig
new file mode 100644
index 0000000..a6d5e09
--- /dev/null
+++ b/src/style.zig
@@ -0,0 +1,23 @@
+//! Helper function collection to provide ascii encodings for styling outputs.
+//! Stylings are implemented such that they can be nested in anyway to support
+//! multiple styles (i.e. bold and italic).
+//!
+//! Stylings however also include highlighting for specific terminal capabilities.
+//! For example url highlighting.
+const std = @import("std");
+
+// TODO: implement helper functions for the following stylings:
+// - bold
+// - italic
+// - underline
+// - curly line
+// - strike through
+// - reverse
+// - blink
+// - color:
+//   - foreground
+//   - background
+
+// TODO: implement helper functions for terminal capabilities:
+// - links / url display (osc 8)
+// - show / hide cursor?
diff --git a/src/terminal.zig b/src/terminal.zig
index 5ef1d3f..28af695 100644
--- a/src/terminal.zig
+++ b/src/terminal.zig
@@ -1,4 +1,5 @@
 const std = @import("std");
+const Key = @import("key.zig");
 pub const code_point = @import("code_point");
 
 const log = std.log.scoped(.terminal);
@@ -13,137 +14,6 @@ pub const Position = struct {
     row: u16,
 };
 
-pub const Key = struct {
-    cp: u21,
-    mod: Modifier = .{},
-
-    pub fn matches(self: Key, other: Key) bool {
-        return std.meta.eql(self, other);
-    }
-
-    // codepoints for keys
-    pub const tab: u21 = 0x09;
-    pub const enter: u21 = 0x0D;
-    pub const escape: u21 = 0x1B;
-    pub const space: u21 = 0x20;
-    pub const backspace: u21 = 0x7F;
-
-    // kitty key encodings (re-used here)
-    pub const insert: u21 = 57348;
-    pub const delete: u21 = 57349;
-    pub const left: u21 = 57350;
-    pub const right: u21 = 57351;
-    pub const up: u21 = 57352;
-    pub const down: u21 = 57353;
-    pub const page_up: u21 = 57354;
-    pub const page_down: u21 = 57355;
-    pub const home: u21 = 57356;
-    pub const end: u21 = 57357;
-    pub const caps_lock: u21 = 57358;
-    pub const scroll_lock: u21 = 57359;
-    pub const num_lock: u21 = 57360;
-    pub const print_screen: u21 = 57361;
-    pub const pause: u21 = 57362;
-    pub const menu: u21 = 57363;
-    pub const f1: u21 = 57364;
-    pub const f2: u21 = 57365;
-    pub const f3: u21 = 57366;
-    pub const f4: u21 = 57367;
-    pub const f5: u21 = 57368;
-    pub const f6: u21 = 57369;
-    pub const f7: u21 = 57370;
-    pub const f8: u21 = 57371;
-    pub const f9: u21 = 57372;
-    pub const f10: u21 = 57373;
-    pub const f11: u21 = 57374;
-    pub const f12: u21 = 57375;
-    pub const f13: u21 = 57376;
-    pub const f14: u21 = 57377;
-    pub const f15: u21 = 57378;
-    pub const @"f16": u21 = 57379;
-    pub const f17: u21 = 57380;
-    pub const f18: u21 = 57381;
-    pub const f19: u21 = 57382;
-    pub const f20: u21 = 57383;
-    pub const f21: u21 = 57384;
-    pub const f22: u21 = 57385;
-    pub const f23: u21 = 57386;
-    pub const f24: u21 = 57387;
-    pub const f25: u21 = 57388;
-    pub const f26: u21 = 57389;
-    pub const f27: u21 = 57390;
-    pub const f28: u21 = 57391;
-    pub const f29: u21 = 57392;
-    pub const f30: u21 = 57393;
-    pub const f31: u21 = 57394;
-    pub const @"f32": u21 = 57395;
-    pub const f33: u21 = 57396;
-    pub const f34: u21 = 57397;
-    pub const f35: u21 = 57398;
-    pub const kp_0: u21 = 57399;
-    pub const kp_1: u21 = 57400;
-    pub const kp_2: u21 = 57401;
-    pub const kp_3: u21 = 57402;
-    pub const kp_4: u21 = 57403;
-    pub const kp_5: u21 = 57404;
-    pub const kp_6: u21 = 57405;
-    pub const kp_7: u21 = 57406;
-    pub const kp_8: u21 = 57407;
-    pub const kp_9: u21 = 57408;
-    pub const kp_decimal: u21 = 57409;
-    pub const kp_divide: u21 = 57410;
-    pub const kp_multiply: u21 = 57411;
-    pub const kp_subtract: u21 = 57412;
-    pub const kp_add: u21 = 57413;
-    pub const kp_enter: u21 = 57414;
-    pub const kp_equal: u21 = 57415;
-    pub const kp_separator: u21 = 57416;
-    pub const kp_left: u21 = 57417;
-    pub const kp_right: u21 = 57418;
-    pub const kp_up: u21 = 57419;
-    pub const kp_down: u21 = 57420;
-    pub const kp_page_up: u21 = 57421;
-    pub const kp_page_down: u21 = 57422;
-    pub const kp_home: u21 = 57423;
-    pub const kp_end: u21 = 57424;
-    pub const kp_insert: u21 = 57425;
-    pub const kp_delete: u21 = 57426;
-    pub const kp_begin: u21 = 57427;
-    pub const media_play: u21 = 57428;
-    pub const media_pause: u21 = 57429;
-    pub const media_play_pause: u21 = 57430;
-    pub const media_reverse: u21 = 57431;
-    pub const media_stop: u21 = 57432;
-    pub const media_fast_forward: u21 = 57433;
-    pub const media_rewind: u21 = 57434;
-    pub const media_track_next: u21 = 57435;
-    pub const media_track_previous: u21 = 57436;
-    pub const media_record: u21 = 57437;
-    pub const lower_volume: u21 = 57438;
-    pub const raise_volume: u21 = 57439;
-    pub const mute_volume: u21 = 57440;
-    pub const left_shift: u21 = 57441;
-    pub const left_control: u21 = 57442;
-    pub const left_alt: u21 = 57443;
-    pub const left_super: u21 = 57444;
-    pub const left_hyper: u21 = 57445;
-    pub const left_meta: u21 = 57446;
-    pub const right_shift: u21 = 57447;
-    pub const right_control: u21 = 57448;
-    pub const right_alt: u21 = 57449;
-    pub const right_super: u21 = 57450;
-    pub const right_hyper: u21 = 57451;
-    pub const right_meta: u21 = 57452;
-    pub const iso_level_3_shift: u21 = 57453;
-    pub const iso_level_5_shift: u21 = 57454;
-};
-
-pub const Modifier = struct {
-    shift: bool = false,
-    alt: bool = false,
-    ctrl: bool = false,
-};
-
 // Ref: https://vt100.net/docs/vt510-rm/DECRPM.html
 pub const ReportMode = enum {
     not_recognized,
@@ -188,6 +58,10 @@ pub fn read(buf: []u8) !usize {
     return try std.posix.read(std.posix.STDIN_FILENO, buf);
 }
 
+pub fn write(buf: []const u8) !usize {
+    return try std.posix.write(std.posix.STDERR_FILENO, buf);
+}
+
 pub fn getCursorPosition() !Position {
     // Needs Raw mode (no wait for \n) to work properly cause
     // control sequence will not be written without it.
diff --git a/src/widget/RawText.zig b/src/widget/RawText.zig
index da7fe89..7db46c2 100644
--- a/src/widget/RawText.zig
+++ b/src/widget/RawText.zig
@@ -1,6 +1,9 @@
 const std = @import("std");
+const terminal = @import("../terminal.zig");
+
 const isTaggedUnion = @import("../event.zig").isTaggedUnion;
 const Error = @import("../event.zig").Error;
+const Key = @import("../key.zig");
 
 pub fn Widget(comptime Event: type) type {
     if (!isTaggedUnion(Event)) {
@@ -8,6 +11,8 @@ pub fn Widget(comptime Event: type) type {
     }
     return struct {
         c: std.ArrayList(u8) = undefined,
+        key: Key = undefined,
+        size: terminal.Size = undefined,
 
         pub fn init(allocator: std.mem.Allocator) @This() {
             return .{ .c = std.ArrayList(u8).init(allocator) };
@@ -19,15 +24,24 @@ pub fn Widget(comptime Event: type) type {
         }
 
         pub fn handle(this: *@This(), event: Event) ?Event {
-            // ignore the event for now
-            _ = this;
-            _ = event;
+            switch (event) {
+                // store the received size
+                .resize => |size| {
+                    this.size = size;
+                },
+                .key => |key| {
+                    this.key = key;
+                },
+                else => {},
+            }
             return null;
         }
 
         pub fn content(this: *@This()) !*std.ArrayList(u8) {
             this.c.clearRetainingCapacity();
-            try this.c.appendSlice("This is a simple test");
+            const writer = this.c.writer();
+            try std.fmt.format(writer, "The terminal has a reported size of [cols: {d}, rows: {d}]\n", .{ this.size.cols, this.size.rows });
+            try std.fmt.format(writer, "User entered key: {any}\n", .{this.key});
             return &this.c;
         }
     };