darkfi/bin/app/src/ui/text_scramble.rs

/* This file is part of DarkFi (https://dark.fi)
 *
 * Copyright (C) 2020-2026 Dyne.org foundation
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

use async_trait::async_trait;
use darkfi::system::msleep;
use parking_lot::Mutex as SyncMutex;
use rand::{rngs::OsRng, Rng};
use std::{ops::Range, sync::Arc};
use tracing::instrument;

use crate::{
    gfx::{gfxtag, DrawCall, DrawInstruction, EpochCache, Rectangle, RenderApi, Renderer},
    mesh::MeshBuilder,
    prop::{
        PropertyAtomicGuard, PropertyBool, PropertyColor, PropertyEnum, PropertyFloat32,
        PropertyRect, PropertyStr, PropertyUint32, Role,
    },
    scene::{Pimpl, SceneNodeWeak},
    text,
    util::i18n::I18nBabelFish,
    ExecutorPtr,
};

use super::{DrawUpdate, OnModify, RedrawTrigger, UIObject};

pub type TextScramblePtr = Arc<TextScramble>;

/// Glyphs shown for characters that have not locked in yet
const SCRAMBLE_GLYPHS: &[char] = &[
    '!', '<', '>', '-', '_', '/', '\\', '[', ']', '{', '}', '(', ')', '=', '+', '*', '^', '?', '#',
    '$', '%', '&', '@', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
];

struct ScrambleState {
    /// Fully solved target text
    target: Vec<char>,
    /// Per-character solve flags, false means still scrambling
    solved: Vec<bool>,
}

impl ScrambleState {
    fn new(target: &str) -> Self {
        let target: Vec<char> = target.chars().collect();
        let solved = vec![false; target.len()];
        Self { target, solved }
    }

    fn reset(&mut self, target: &str) {
        self.target = target.chars().collect();
        self.solved = vec![false; self.target.len()];
    }

    fn solved_all(&self) -> bool {
        self.solved.iter().all(|&solved| solved)
    }

    /// Give every unsolved character a chance to lock in
    fn tick(&mut self, solve_probability: f32) {
        for solved in self.solved.iter_mut() {
            if *solved {
                continue
            }
            if OsRng.gen::<f32>() < solve_probability {
                *solved = true;
            }
        }
    }

    /// Current text with unsolved characters replaced by random glyphs,
    /// plus the byte ranges of those glyphs. Whitespace is kept so the
    /// word layout stays stable.
    fn display(&self) -> (String, Vec<Range<usize>>) {
        let mut text = String::new();
        let mut ranges = vec![];
        for (&c, &solved) in self.target.iter().zip(self.solved.iter()) {
            let start = text.len();
            if solved || c.is_whitespace() {
                text.push(c);
            } else {
                text.push(SCRAMBLE_GLYPHS[OsRng.gen_range(0..SCRAMBLE_GLYPHS.len())]);
                ranges.push(start..text.len());
            }
        }
        (text, ranges)
    }
}

pub struct TextScramble {
    node: SceneNodeWeak,
    renderer: Renderer,
    i18n_fish: I18nBabelFish,
    redraw: RedrawTrigger,
    tasks: SyncMutex<Vec<smol::Task<()>>>,

    dc_key: u64,

    rect: PropertyRect,
    height: PropertyFloat32,
    z_index: PropertyUint32,
    priority: PropertyUint32,
    text: PropertyStr,
    font_size: PropertyFloat32,
    text_color: PropertyColor,
    scramble_color: PropertyColor,
    lineheight: PropertyFloat32,
    text_align: PropertyEnum,
    overflow_wrap: PropertyEnum,
    use_i18n: PropertyBool,
    debug: PropertyBool,
    solve_probability: PropertyFloat32,
    tick_interval: PropertyUint32,

    window_scale: PropertyFloat32,
    /// Current scramble animation state
    scramble: SyncMutex<ScrambleState>,
    /// Cached layout + rendered instrs. Empty means stale: recompute in
    /// the draw pass. Layout is the expensive part (shaping, line breaks).
    /// Entries from a dead UI epoch are evicted automatically.
    draw_cache: EpochCache<(text::TextLayout, Vec<DrawInstruction>)>,
}

impl TextScramble {
    pub async fn new(
        node: SceneNodeWeak,
        window_scale: PropertyFloat32,
        renderer: Renderer,
        i18n_fish: I18nBabelFish,
        redraw: RedrawTrigger,
    ) -> Pimpl {
        let node_ref = &node.upgrade().unwrap();
        let rect = PropertyRect::wrap(node_ref, Role::Internal, "rect").unwrap();
        let height = PropertyFloat32::wrap(node_ref, Role::Internal, "height", 0).unwrap();
        let z_index = PropertyUint32::wrap(node_ref, Role::Internal, "z_index", 0).unwrap();
        let priority = PropertyUint32::wrap(node_ref, Role::Internal, "priority", 0).unwrap();
        let text = PropertyStr::wrap(node_ref, Role::Internal, "text", 0).unwrap();
        let font_size = PropertyFloat32::wrap(node_ref, Role::Internal, "font_size", 0).unwrap();
        let text_color = PropertyColor::wrap(node_ref, Role::Internal, "text_color").unwrap();
        let scramble_color =
            PropertyColor::wrap(node_ref, Role::Internal, "scramble_color").unwrap();
        let lineheight = PropertyFloat32::wrap(node_ref, Role::Internal, "lineheight", 0).unwrap();
        let text_align = PropertyEnum::wrap(node_ref, Role::Internal, "text_align", 0).unwrap();
        let overflow_wrap =
            PropertyEnum::wrap(node_ref, Role::Internal, "overflow_wrap", 0).unwrap();
        let use_i18n = PropertyBool::wrap(node_ref, Role::Internal, "use_i18n", 0).unwrap();
        let debug = PropertyBool::wrap(node_ref, Role::Internal, "debug", 0).unwrap();
        let solve_probability =
            PropertyFloat32::wrap(node_ref, Role::Internal, "solve_probability", 0).unwrap();
        let tick_interval =
            PropertyUint32::wrap(node_ref, Role::Internal, "tick_interval", 0).unwrap();

        let draw_cache = EpochCache::new(&renderer);

        let target = Self::translated_target(&text.get(), &use_i18n, &i18n_fish);
        let scramble = SyncMutex::new(ScrambleState::new(&target));

        let self_ = Arc::new(Self {
            node,
            renderer,
            i18n_fish,
            redraw,
            tasks: SyncMutex::new(vec![]),
            dc_key: OsRng.gen(),

            rect,
            height,
            z_index,
            priority,
            text,
            font_size,
            text_color,
            scramble_color,
            lineheight,
            text_align,
            overflow_wrap,
            use_i18n,
            debug,
            solve_probability,
            tick_interval,

            window_scale,
            scramble,
            draw_cache,
        });

        Pimpl::TextScramble(self_)
    }

    fn translated_target(text: &str, use_i18n: &PropertyBool, i18n_fish: &I18nBabelFish) -> String {
        if use_i18n.get() {
            if let Some(trans) = i18n_fish.tr(text) {
                return trans
            }
            return format!("tr err: {}", text)
        }
        text.to_string()
    }

    /// Throw away the current solve state and rescramble from the target text
    fn reset_scramble(&self) {
        let target = Self::translated_target(&self.text.get(), &self.use_i18n, &self.i18n_fish);
        self.scramble.lock().reset(&target);
    }

    fn make_layout(&self) -> text::TextLayout {
        let (text, scramble_ranges) = self.scramble.lock().display();
        let font_size = self.font_size.get();
        let lineheight = self.lineheight.get();
        let text_color = self.text_color.get();
        let scramble_color = self.scramble_color.get();
        let window_scale = self.window_scale.get();
        let width = self.rect.get_width();
        let text_align = match self.text_align.get().as_str() {
            "end" => parley::Alignment::End,
            "left" => parley::Alignment::Left,
            "center" => parley::Alignment::Center,
            "right" => parley::Alignment::Right,
            "justify" => parley::Alignment::Justify,
            _ => parley::Alignment::Start,
        };
        let overflow_wrap = match self.overflow_wrap.get().as_str() {
            "anywhere" => parley::OverflowWrap::Anywhere,
            "break-word" => parley::OverflowWrap::BreakWord,
            _ => parley::OverflowWrap::Normal,
        };

        let scramble_colors =
            scramble_ranges.into_iter().map(|range| (range, scramble_color)).collect::<Vec<_>>();

        text::make_layout2(
            &text,
            text_color,
            font_size,
            lineheight,
            window_scale,
            Some(width),
            &[],
            &scramble_colors,
            text_align,
            overflow_wrap,
        )
    }

    fn regen_mesh(&self, layout: &text::TextLayout) -> Vec<DrawInstruction> {
        let mut debug_opts = text::DebugRenderOptions::OFF;
        if self.debug.get() {
            debug_opts |= text::DebugRenderOptions::BASELINE;
        }

        text::render_layout_with_opts(layout, debug_opts, &self.renderer, gfxtag!("text_scramble"))
    }

    fn get_draw_calls(
        &self,
        atom: &mut PropertyAtomicGuard,
        parent_rect: Rectangle,
    ) -> Option<DrawUpdate> {
        // Rect property is its own memo: compare before/after eval.
        let prev_rect = self.rect.get();
        self.rect.eval(atom, &parent_rect).ok()?;
        let rect = self.rect.get();
        let rect_changed = rect != prev_rect;

        // Layout depends on the width, so a rect change invalidates the
        // layout even if the text itself did not change. Compute under the
        // cache lock: the compute is synchronous, so concurrent invalidations
        // either land before (seen as None) or after (they clear our result).
        if rect_changed {
            self.draw_cache.clear();
        }
        let (layout, mut instrs) = self.draw_cache.get_or_insert_with(|| {
            let layout = self.make_layout();
            let mut instrs = vec![DrawInstruction::Move(rect.pos())];
            instrs.append(&mut self.regen_mesh(&layout));
            (layout, instrs)
        });

        // Height output for parents that depend on it.
        self.height.set(atom, layout.height());

        if self.debug.get() {
            let rect = self.rect.get().with_zero_pos();
            let mut mesh = MeshBuilder::new(gfxtag!("text_scramble_debug-rect"));
            mesh.draw_outline(&rect, [0., 1., 0., 0.7], 1.);
            let mesh = mesh.alloc(&self.renderer).draw_untextured();
            instrs.push(DrawInstruction::Draw(mesh));
        }

        Some(DrawUpdate {
            key: self.dc_key,
            draw_calls: vec![(
                self.dc_key,
                DrawCall::new(instrs, vec![], self.z_index.get(), "text_scramble"),
            )],
        })
    }
}

#[async_trait]
impl UIObject for TextScramble {
    fn priority(&self) -> u32 {
        self.priority.get()
    }

    async fn start(self: Arc<Self>, ex: ExecutorPtr) {
        let me = Arc::downgrade(&self);

        let mut on_modify = OnModify::new(ex.clone(), self.node.clone(), me.clone());
        // Invalidate the cache, then request a pass. Internal-role echoes
        // (the pass's own evals) are skipped.
        on_modify.when_change_external(self.rect.prop(), |self_, _| async move {
            self_.draw_cache.clear();
            self_.redraw.trigger();
        });
        on_modify.when_change_external(self.z_index.prop(), |self_, _| async move {
            self_.draw_cache.clear();
            self_.redraw.trigger();
        });
        on_modify.when_change_external(self.text.prop(), |self_, _| async move {
            self_.reset_scramble();
            self_.draw_cache.clear();
            self_.redraw.trigger();
        });
        on_modify.when_change_external(self.text_align.prop(), |self_, _| async move {
            self_.draw_cache.clear();
            self_.redraw.trigger();
        });
        on_modify.when_change_external(self.font_size.prop(), |self_, _| async move {
            self_.draw_cache.clear();
            self_.redraw.trigger();
        });
        on_modify.when_change_external(self.text_color.prop(), |self_, _| async move {
            self_.draw_cache.clear();
            self_.redraw.trigger();
        });
        on_modify.when_change_external(self.scramble_color.prop(), |self_, _| async move {
            self_.draw_cache.clear();
            self_.redraw.trigger();
        });
        on_modify.when_change_external(self.debug.prop(), |self_, _| async move {
            self_.draw_cache.clear();
            self_.redraw.trigger();
        });
        *self.tasks.lock() = on_modify.tasks;

        // Scramble animation loop. Weak ref: the task must not keep the
        // node alive, and self_ is dropped before each sleep so a dead
        // node ends the loop on the next upgrade.
        let anim_task = ex.spawn(async move {
            loop {
                let delay = {
                    let Some(self_) = me.upgrade() else { break };

                    let interval = self_.tick_interval.get().max(1);
                    let probability = self_.solve_probability.get();

                    let running = {
                        let mut scramble = self_.scramble.lock();
                        let running = !scramble.solved_all();
                        if running {
                            scramble.tick(probability);
                        }
                        running
                    };

                    if running {
                        self_.draw_cache.clear();
                        self_.redraw.trigger();
                    }

                    interval as u64
                };

                msleep(delay).await;
            }
        });
        self.tasks.lock().push(anim_task);
    }

    fn stop(&self) {
        self.tasks.lock().clear();
        self.draw_cache.clear();
    }

    #[instrument(target = "ui::text_scramble")]
    async fn draw(
        &self,
        parent_rect: Rectangle,
        atom: &mut PropertyAtomicGuard,
    ) -> Option<DrawUpdate> {
        self.get_draw_calls(atom, parent_rect)
    }

    fn set_i18n(&self, i18n_fish: &I18nBabelFish) {
        self.i18n_fish.set(i18n_fish);
    }
}

impl Drop for TextScramble {
    fn drop(&mut self) {
        self.renderer.replace_draw_calls(vec![(self.dc_key, Default::default())]);
    }
}

impl std::fmt::Debug for TextScramble {
    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
        write!(f, "{:?}", self.node.upgrade().unwrap())
    }
}