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use std::collections::VecDeque;
use std::fs::{self, File, OpenOptions, TryLockError};
use std::io::{BufWriter, Write};
use std::path::PathBuf;
use std::time::{Duration, Instant};
use chrono::Local;
use eframe::egui;
mod render;
use render::{Glyph, build_job, glyph_factor, shake_offset, word_count};
const SYNC_INTERVAL: Duration = Duration::from_secs(30);
const FONT_SIZE: f32 = 28.0;
pub struct WriteApp {
document: String, // file mirror; retained for 1c word count
visible: VecDeque<Glyph>, // render buffer; pruned each frame as glyphs fully fade
writer: BufWriter<File>, // append-only handle to the session .md
visibility_head: f64, // glyphs born before this fade out at once (visual clear)
shake_start: f64, // time of the last backspace-clear; drives the wiggle feedback
enter_run: u8, // 0 = none, 1 = one Enter written, 2+ = cleared / no-op
last_was_backspace: bool,
menu_open: bool,
fullscreen: bool, // live window state; toggled from the Esc menu (W)
darker: bool, // session-only render state; toggled from the Esc menu (D)
entered_fullscreen: bool, // one-shot: launch-time deferred fullscreen, applied once focused
seed_words: usize, // day-total words already on disk at open time
last_sync: Instant,
}
/// Open today's append-only session file (`~/Documents/write/YYYY-MM-DD.md`),
/// creating it if needed, and take an exclusive advisory lock. Invocations on the
/// same day share one file; the lock ensures only one `write` process appends to
/// it at a time. Returns `Ok(None)` when another process already holds today's
/// lock — the caller should exit quietly.
pub fn open_session_file() -> Result<Option<(File, usize)>, Box<dyn std::error::Error + Send + Sync>>
{
let mut dir: PathBuf = dirs::document_dir()
.or_else(dirs::home_dir)
.ok_or("no Documents or home directory")?;
dir.push("write");
fs::create_dir_all(&dir)?;
dir.push(format!("{}.md", Local::now().format("%Y-%m-%d")));
let file = OpenOptions::new().create(true).append(true).open(&dir)?;
// Advisory flock tied to this fd; released automatically when the process exits.
match file.try_lock() {
Ok(()) => {
let seed = word_count(&fs::read_to_string(&dir).unwrap_or_default());
Ok(Some((file, seed)))
}
Err(TryLockError::WouldBlock) => Ok(None),
Err(TryLockError::Error(e)) => Err(Box::new(e)),
}
}
impl WriteApp {
pub fn new(_cc: &eframe::CreationContext<'_>, file: File, seed_words: usize) -> Self {
Self {
document: String::new(),
visible: VecDeque::new(),
writer: BufWriter::new(file),
visibility_head: 0.0,
shake_start: f64::NEG_INFINITY,
enter_run: 0,
last_was_backspace: false,
menu_open: false,
fullscreen: false,
darker: false,
entered_fullscreen: false,
seed_words,
last_sync: Instant::now(),
}
}
// Append raw text to the file mirror, the file, and the visible render buffer.
fn append(&mut self, s: &str, now: f64) {
self.document.push_str(s);
if let Err(e) = self.writer.write_all(s.as_bytes()) {
eprintln!("write: failed to append to file: {e}");
}
self.visible
.extend(s.chars().map(|ch| Glyph { ch, birth: now }));
}
fn fsync(&mut self) {
if let Err(e) = self.writer.flush() {
eprintln!("write: flush failed: {e}");
}
if let Err(e) = self.writer.get_ref().sync_data() {
eprintln!("write: sync_data failed: {e}");
}
}
}
impl eframe::App for WriteApp {
fn ui(&mut self, ui: &mut egui::Ui, _frame: &mut eframe::Frame) {
let ctx = ui.ctx().clone(); // cheap Arc clone; avoids borrow conflict with ui.painter()
// Suppress Tab focus navigation.
ctx.input_mut(|i| {
let _ = i.consume_key(egui::Modifiers::NONE, egui::Key::Tab);
});
let now = ctx.input(|i| i.time);
// Enter fullscreen only once the window has focus, to dodge the launch-time
// activation race that otherwise bounces the Space back to the desktop. Keep
// repainting until then so we actually observe the focus transition.
if !self.entered_fullscreen {
if ctx.input(|i| i.focused) {
ctx.send_viewport_cmd(egui::ViewportCommand::Fullscreen(true));
self.entered_fullscreen = true;
self.fullscreen = true;
} else {
ctx.request_repaint();
}
}
// Copy events out, keep the input closure short.
let events = ctx.input(|i| i.events.clone());
// Closing the menu is deferred to after this batch so the trailing Text
// event a key emits (e.g. W's "w") is still swallowed by the menu gate
// and doesn't leak into the document.
let mut close_menu = false;
for event in events {
if self.menu_open {
if let egui::Event::Key {
key, pressed: true, ..
} = event
{
match key {
egui::Key::Q => ctx.send_viewport_cmd(egui::ViewportCommand::Close),
egui::Key::W => {
self.fullscreen = !self.fullscreen;
ctx.send_viewport_cmd(egui::ViewportCommand::Fullscreen(
self.fullscreen,
));
close_menu = true; // resume writing in the new window state
}
egui::Key::D => {
self.darker = !self.darker;
close_menu = true; // resume writing in the new brightness
}
egui::Key::Escape => close_menu = true, // resume writing
_ => {}
}
}
continue; // ignore Text and everything else while the menu is open
}
match event {
egui::Event::Text(t) => {
self.append(&t, now); // Text already handles shift/dead/accents
self.enter_run = 0;
self.last_was_backspace = false;
}
egui::Event::Key {
key,
modifiers,
pressed: true,
..
} => {
if modifiers.command {
// ignore Cmd/Ctrl combos (paste, undo, ...)
continue;
}
match key {
egui::Key::Enter => {
match self.enter_run {
0 => {
self.append("\n\n", now);
self.enter_run = 1;
}
1 => {
// Second consecutive Enter: clear the screen (no newlines).
self.visibility_head = now;
self.enter_run = 2;
}
_ => {} // already cleared → no-op
}
self.last_was_backspace = false;
}
egui::Key::Backspace => {
if !self.last_was_backspace {
self.append(" ", now);
self.visibility_head = now; // clear the screen
self.shake_start = now; // kick off the "no" wiggle
}
self.last_was_backspace = true;
self.enter_run = 0;
}
egui::Key::Escape => {
self.menu_open = true;
self.fsync(); // durable flush on menu open
}
_ => {} // arrows, Delete, Tab, Home, End, PageUp/Down → no-op
}
}
_ => {} // Event::Paste, Event::Ime, pointer, etc. → ignored
}
}
if close_menu {
self.menu_open = false;
}
// Periodic durability: flush + sync_data ~every 30s.
if self.last_sync.elapsed() >= SYNC_INTERVAL {
self.fsync();
self.last_sync = Instant::now();
}
// Prune fully-faded glyphs from the front (oldest first; glyphs are in birth order).
// Uses the combined factor so clear-faded glyphs drain too.
while let Some(front) = self.visible.front() {
if glyph_factor(front.birth, now, self.visibility_head) <= 0.0 {
self.visible.pop_front();
} else {
break;
}
}
// Render: full-rect black background + a center-anchored, centered fading galley.
let rect = ctx.content_rect();
let margin = 40.0_f32;
let max_col = 760.0_f32;
let col_width = (rect.width() - 2.0 * margin).clamp(0.0, max_col);
let body = if self.darker {
egui::Color32::from_gray(30)
} else {
egui::Color32::from_gray(220)
};
let job = build_job(
self.visible.make_contiguous(),
now,
self.visibility_head,
egui::FontId::proportional(FONT_SIZE),
body,
col_width,
);
let painter = ui.painter();
painter.rect_filled(rect, 0.0, egui::Color32::BLACK);
let galley = painter.layout_job(job);
let dx = shake_offset(now - self.shake_start);
let x = rect.left() + (rect.width() - col_width) * 0.5 + dx;
let x_height = 0.5 * FONT_SIZE; // egui 0.34 has no x-height metric; 0.5em is close enough
let center_y = rect.center().y;
let y = center_y + x_height - galley.size().y; // newest line one x-height below center; older lines scroll up
painter.galley(egui::pos2(x, y), galley, body);
let words = self.seed_words + word_count(&self.document);
if words >= 2 {
let pos = egui::pos2(rect.right() - margin, rect.top() + margin);
painter.text(
pos,
egui::Align2::RIGHT_TOP,
format!("{words} words"),
egui::FontId::proportional(0.5 * FONT_SIZE), // smaller than body
egui::Color32::from_gray(110), // dim gray so the HUD recedes
);
}
if self.menu_open {
let words = self.seed_words + word_count(&self.document);
egui::Window::new("menu")
.title_bar(false)
.resizable(false)
.collapsible(false)
.anchor(egui::Align2::CENTER_CENTER, egui::Vec2::ZERO)
.show(&ctx, |ui| {
ui.vertical_centered(|ui| {
ui.label(egui::RichText::new(format!("{words} words")).size(24.0));
ui.add_space(8.0);
let win_hint = if self.fullscreen {
"W — windowed"
} else {
"W — fullscreen"
};
let dark_hint = if self.darker {
"D — normal"
} else {
"D — darker"
};
ui.label(format!(
"Q — quit Esc — resume {win_hint} {dark_hint}"
));
});
});
}
if self.visible.is_empty() {
// Idle: nothing to animate. Wake only to run the periodic fsync.
ctx.request_repaint_after(SYNC_INTERVAL.saturating_sub(self.last_sync.elapsed()));
} else {
// Text still visible/fading: animate.
ctx.request_repaint();
}
}
fn clear_color(&self, _visuals: &egui::Visuals) -> [f32; 4] {
[0.0, 0.0, 0.0, 1.0]
}
fn on_exit(&mut self) {
self.fsync(); // final flush + sync on clean exit
}
}