// Copyright © SixtyFPS GmbH <info@slint.dev>
// SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-2.0 OR LicenseRef-Slint-Software-3.0

// cSpell: ignore androidwindowadapter javahelper
#![doc = include_str!("README.md")]
#![doc(html_logo_url = "https://slint.dev/logo/slint-logo-square-light.svg")]
#![cfg_attr(not(target_os = "android"), allow(rustdoc::broken_intra_doc_links))]
#![cfg(target_os = "android")]
#![cfg_attr(slint_nightly_test, feature(non_exhaustive_omitted_patterns_lint))]
#![cfg_attr(slint_nightly_test, warn(non_exhaustive_omitted_patterns))]

mod androidwindowadapter;
mod javahelper;
mod vsync;

pub mod stg;

#[cfg(all(not(feature = "aa-06"), feature = "aa-05"))]
pub use android_activity_05 as android_activity;
#[cfg(feature = "aa-06")]
pub use android_activity_06 as android_activity;

#[cfg(all(not(feature = "aa-06"), feature = "aa-05"))]
use ndk_08 as ndk;
#[cfg(feature = "aa-06")]
use ndk_09 as ndk;

pub use android_activity::AndroidApp;
use android_activity::PollEvent;
use androidwindowadapter::AndroidWindowAdapter;
use core::ops::ControlFlow;
use core::time::Duration;
use i_slint_core::api::{EventLoopError, PlatformError};
use i_slint_core::platform::{Clipboard, WindowAdapter};
use i_slint_renderer_skia::SkiaRendererExt;
use std::cell::RefCell;
use std::rc::{Rc, Weak};
use std::sync::{Arc, Mutex};

thread_local! {
    static CURRENT_WINDOW: RefCell<Weak<AndroidWindowAdapter>> = RefCell::new(Default::default());
}

pub struct AndroidPlatform {
    app: AndroidApp,
    window: Rc<AndroidWindowAdapter>,
    event_listener: Option<Box<dyn Fn(&PollEvent<'_>)>>,
    context: core::cell::OnceCell<i_slint_core::SlintContextWeak>,
}

impl AndroidPlatform {
    /// Instantiate a new Android backend given the [`android_activity::AndroidApp`]
    ///
    /// Pass the returned value to [`slint::platform::set_platform()`](`i_slint_core::platform::set_platform()`)
    ///
    /// # Example
    /// ```
    /// #[cfg(target_os = "android")]
    /// #[unsafe(no_mangle)]
    /// fn android_main(app: i_slint_backend_android_activity::AndroidApp) {
    ///     slint::platform::set_platform(Box::new(
    ///         i_slint_backend_android_activity::AndroidPlatform::new(app),
    ///     ))
    ///     .unwrap();
    ///     // ... your slint application ...
    /// }
    /// ```
    pub fn new(app: AndroidApp) -> Self {
        let window = AndroidWindowAdapter::new(app.clone());
        CURRENT_WINDOW.set(Rc::downgrade(&window));
        Self { app, window, event_listener: None, context: Default::default() }
    }

    /// Instantiate a new Android backend given the [`android_activity::AndroidApp`]
    /// and a function to process the events.
    ///
    /// This is the same as [`AndroidPlatform::new()`], but it allow you to get notified
    /// of events.
    ///
    /// Pass the returned value to [`slint::platform::set_platform()`](`i_slint_core::platform::set_platform()`)
    ///
    /// # Example
    /// ```
    /// #[cfg(target_os = "android")]
    /// #[unsafe(no_mangle)]
    /// fn android_main(app: i_slint_backend_android_activity::AndroidApp) {
    ///     slint::platform::set_platform(Box::new(
    ///         i_slint_backend_android_activity::AndroidPlatform::new_with_event_listener(
    ///             app,
    ///             |event| { eprintln!("got event {event:?}") }
    ///         ),
    ///     ))
    ///     .unwrap();
    ///     // ... your slint application ...
    /// }
    /// ```
    pub fn new_with_event_listener(
        app: AndroidApp,
        listener: impl Fn(&PollEvent<'_>) + 'static,
    ) -> Self {
        let mut this = Self::new(app);
        this.event_listener = Some(Box::new(listener));
        this
    }
}

impl i_slint_core::platform::Platform for AndroidPlatform {
    fn create_window_adapter(&self) -> Result<Rc<dyn WindowAdapter>, PlatformError> {
        Ok(self.window.clone())
    }
    fn run_event_loop(&self) -> Result<(), PlatformError> {
        let ctx = self
            .context
            .get()
            .and_then(|ctx| ctx.upgrade())
            .expect("the event loop runs inside the context that owns this platform");
        // 120Hz scroll fix (docs/BUGS/scroll-jank-120hz.md): enable the
        // render-ahead pipeline in the wgpu surface. It is only ACTIVE per-
        // frame while `locked` (VSYNC_LOCKED_RENDER && animating); unlocked
        // renders always present immediately. See RENDER_AHEAD / RENDER_AHEAD_ACTIVE.
        i_slint_renderer_skia::wgpu_30_surface::vkprobe::RENDER_AHEAD
            .store(true, std::sync::atomic::Ordering::Relaxed);
        let vsync = vsync::VsyncDriver::new(self.app.create_waker());
        // RENDER_AHEAD flush: tracks the previous iteration's locked state so
        // that when animation ends we do one final render() — which presents
        // the frame held by the render-ahead pipeline (otherwise the last
        // content change would never be displayed).
        let mut prev_locked = false;
        loop {
            let mut timeout = ctx.duration_until_next_timer_update();
            // While animating, the vsync thread wakes this loop at each display refresh
            // so rendering tracks the refresh rate instead of a fixed poll timeout.
            //
            // We also treat an ACTIVE POINTER DRAG as "animating" (see
            // stg::pointer_recently_active): during a direct drag Slint has no
            // physics animation, so has_active_animations() is false and, without
            // this, the loop would sleep until the next timer (16 ms) between
            // pointer events → 16-30 ms frame gaps. Keeping the vsync driver
            // alive makes poll_events wake at each display refresh instead.
            let animating = self.window.window.has_active_animations()
                || stg::pointer_recently_active();
            vsync.set_animating(animating);
            if animating {
                // When animating (scrolling/flinging), cap the poll timeout to 6ms
                // as a safety net in case a vsync wake is lost. Rendering still
                // only happens when `pending_redraw` is set (content actually
                // changed) — we do NOT force a redraw here, which would waste
                // GPU re-rendering an unchanged scene on every wake.
                let frame_duration = Duration::from_millis(6);
                timeout = Some(timeout.map_or(frame_duration, |x| x.min(frame_duration)));
            }
            // `request_redraw()` only raises the flag, so a request issued outside the
            // poll would otherwise wait here for an unrelated wakeup.
            // EXCEPT in vsync-locked mode: the render is deliberately deferred
            // to the vsync WAKE, so a zero timeout here would busy-spin the
            // loop at ~100 kHz (timeout event, no wake, flag never consumed)
            // for up to 8.3 ms after every input event. Block up to the cap
            // instead and let the wake arrive.
            let pr_before = self.window.pending_redraw.get();
            let locked = stg::VSYNC_LOCKED_RENDER
                .load(std::sync::atomic::Ordering::Relaxed)
                && animating;
            if pr_before && !locked {
                timeout = Some(Duration::ZERO);
            }
            // Jank-hunt: classify the timeout path to explain the 1451 iters/s
            // busy-spin. ZERO = forced by pending_redraw; CAP = 6 ms anim cap;
            // NATURAL = the next timer (>= ~7 ms).
            if stg::IT_ON.load(std::sync::atomic::Ordering::Relaxed) {
                let to_ms = timeout.map(|d| d.as_secs_f64() * 1000.0).unwrap_or(f64::MAX);
                let kind = if pr_before {
                    0
                } else if animating && to_ms <= 6.0 {
                    1
                } else {
                    2
                };
                stg::note_timeout_class(kind);
            }
            // STG (jank-hunt instrumentation): reset per-iteration marks.
            {
                let pr = stg::S_RENDER_START.load(std::sync::atomic::Ordering::Relaxed);
                let pe = stg::S_RENDER_END.load(std::sync::atomic::Ordering::Relaxed);
                if pr != 0 && pe != 0 {
                    stg::S_LAST_RENDER_US
                        .store(pe - pr, std::sync::atomic::Ordering::Relaxed);
                }
            }
            let t_start = stg::now_us();
            let timeout_ms = timeout.map(|d| d.as_millis() as u64).unwrap_or(u64::MAX);
            stg::S_START.store(t_start, std::sync::atomic::Ordering::Relaxed);
            stg::S_FIRST_EV.store(0, std::sync::atomic::Ordering::Relaxed);
            stg::S_TIMER_US.store(0, std::sync::atomic::Ordering::Relaxed);
            stg::S_EVENT_US.store(0, std::sync::atomic::Ordering::Relaxed);
            stg::S_N_EVENTS.store(0, std::sync::atomic::Ordering::Relaxed);
            let mut r = Ok(ControlFlow::Continue(()));
            // Jank-hunt / 120Hz: did this poll return because the vsync driver
            // (or any waker) fired? Used to lock rendering to the vsync edge
            // (see the render decision below) instead of rendering in reaction
            // to input events (which arrive at a random phase in the slot and
            // push the present past the ~5.5 ms compositor deadline → every
            // frame shown one vsync late → effective 60 Hz + judder).
            let mut saw_wake = false;
            // H5 (hypotheses-120hz.md): CPU time inside poll_events. wall≫cpu
            // ⇒ the UI thread slept/descheduled while the wake byte was
            // pending (epoll not woken, or the thread lost the CPU); wall≈cpu
            // ⇒ the loop spun inside ALooper.
            let __cpu_p0 = stg::thread_cpu_us();
            self.app.poll_events(timeout, |e| {
                if matches!(e, PollEvent::Wake) {
                    saw_wake = true;
                }
                if stg::S_FIRST_EV.load(std::sync::atomic::Ordering::Relaxed) == 0 {
                    stg::S_FIRST_EV
                        .store(stg::now_us(), std::sync::atomic::Ordering::Relaxed);
                }
                let t3_start = stg::now_us();
                let t3_cpu_start = stg::thread_cpu_us();
                r = self.window.process_event(&e);
                let t3_end = stg::now_us();
                let t3_cpu_end = stg::thread_cpu_us();
                let __dt3 = t3_end - t3_start;
                // Jank-hunt: count wake sources. If WAKE events dominate, the
                // loop is being woken far more often than vsync (120/s) or input,
                // which explains the 1600 iters/s busy-spin.
                match e {
                    PollEvent::Wake => { stg::WAKE_COUNT.fetch_add(1, std::sync::atomic::Ordering::Relaxed); }
                    PollEvent::Timeout => { stg::TIMEOUT_EV_COUNT.fetch_add(1, std::sync::atomic::Ordering::Relaxed); }
                    PollEvent::Main(android_activity::MainEvent::InputAvailable) => {
                        stg::INPUT_EV_COUNT.fetch_add(1, std::sync::atomic::Ordering::Relaxed);
                    }
                    _ => {}
                }
                // Jank-hunt: identify which MainEvent variant causes the big
                // `ev` spikes (pointer input is ~2.5 ms max, so a 20 ms event
                // is something else entirely).
                if __dt3 > 5_000 && stg::IT_ON.load(std::sync::atomic::Ordering::Relaxed) {
                    let nm = match e {
                        PollEvent::Main(android_activity::MainEvent::InputAvailable) => "Input",
                        PollEvent::Main(android_activity::MainEvent::InitWindow { .. }) => "InitWin",
                        PollEvent::Main(android_activity::MainEvent::TerminateWindow { .. }) => "TermWin",
                        PollEvent::Main(android_activity::MainEvent::WindowResized { .. }) => "WinResized",
                        PollEvent::Main(android_activity::MainEvent::RedrawNeeded { .. }) => "RedrawNeeded",
                        PollEvent::Main(_) => "Main-other",
                        _ => "NonMain",
                    };
                    stg::log_slow_event(nm, __dt3, t3_cpu_end.saturating_sub(t3_cpu_start));
                }
                stg::S_EVENT_US.fetch_add(__dt3, std::sync::atomic::Ordering::Relaxed);
                stg::S_N_EVENTS.fetch_add(1, std::sync::atomic::Ordering::Relaxed);
                if let Some(event_listener) = &self.event_listener {
                    event_listener(&e)
                }
            });
            let t_poll1 = stg::now_us();
            let __poll_cpu = stg::thread_cpu_us().saturating_sub(__cpu_p0);
            let lv1 = stg::lv_snapshot();

            // Unconditionally update timers and animations on every event-loop wakeup
            ctx.update_timers_and_animations();
            let t2 = stg::now_us();
            stg::S_TIMER_US.store(t2 - t_poll1, std::sync::atomic::Ordering::Relaxed);

            stg::S_POLL_END.store(t2, std::sync::atomic::Ordering::Relaxed);
            if r?.is_break() {
                break;
            }
            let mut render_us = 0u64;
            let mut __render_cpu = 0u64;
            // Jank-hunt / 120Hz: vsync-locked rendering (the native-Android
            // model). While animating, input events only MARK the window dirty;
            // the render happens on the next vsync WAKE, so every present
            // starts at a deterministic phase (vsync edge + wake latency) and
            // lands well inside the compositor's ~5.5 ms deadline. Cost: up
            // to one slot of extra input latency.
            let do_render = if locked {
                // Present EVERY vsync while animating (not only on content
                // change): the regular 120 Hz present stream locks the
                // display cadence. Re-rendering unchanged content is cheap
                // with Skia's incremental pipeline.
                //
                // IMPORTANT: do NOT `pending_redraw.take()` here. The render
                // is driven by the vsync wake, but the pending flag also
                // carries the motion events' invalidations. Consuming it
                // here starves the follow-up unlocked iteration (which runs
                // 0.4 ms later, before the next motion event arrives) of
                // anything to render, collapsing the cadence to 60 Hz
                // (one render per two vsyncs). Letting the flag survive
                // means the next iteration renders too; if the content is
                // unchanged the extra render is invisible.
                //
                // FRESHNESS GUARD: with the early waker (vsync.rs), TWO
                // wakes can arrive per slot — the early one (~0.8 ms BEFORE
                // the vsync edge) and the Choreographer's late fallback
                // (~5 ms after it). The first one of each slot renders;
                // the second must NOT (double render = 2× the slot budget =
                // 60 Hz collapse). The intervals (measured):
                //   late-after-early  = ~5.8 ms   → must be REJECTED
                //   early-after-late  = ~7.5 ms   → must be ACCEPTED
                //   same-kind         = ~8.33 ms  → ACCEPTED
                // Threshold `period − 1.5 ms` (≈6.8 ms) sits between 5.8
                // and 7.5 with ~0.7-1.0 ms of jitter margin on both sides.
                // (A 0.7-period threshold rejects early-after-late and a
                // 1.0-period threshold locks the cadence onto the late
                // wakes — both measured to fragment the burst.)
                let __now_ns = i_slint_renderer_skia::wgpu_30_surface::vkprobe::monotonic_ns();
                let __period_ns = i_slint_renderer_skia::wgpu_30_surface::vkprobe::VSYNC_PERIOD_NS
                    .load(std::sync::atomic::Ordering::Relaxed);
                let __last = i_slint_renderer_skia::wgpu_30_surface::vkprobe::LAST_RENDER_START_NS
                    .load(std::sync::atomic::Ordering::Relaxed);
                let __min_gap = __period_ns.saturating_sub(1_500_000);
                let __fresh = __period_ns == 0
                    || __now_ns.saturating_sub(__last) >= __min_gap;
                if __fresh {
                    i_slint_renderer_skia::wgpu_30_surface::vkprobe::LAST_RENDER_START_NS
                        .store(__now_ns, std::sync::atomic::Ordering::Relaxed);
                }
                saw_wake && __fresh
            } else {
                self.window.pending_redraw.get()
            };
            if do_render {
                // Locked (vsync-wake) renders leave the flag set so the
                // follow-up unlocked iteration renders too (60 Hz collapse,
                // see the do_render note); unlocked renders consume it.
                if !locked {
                    self.window.pending_redraw.take();
                }
                // RENDER_AHEAD (hold-without-present) is DISABLED: the held
                // frame is presented at the start of the NEXT render, i.e.
                // after the next vsync wake's Choreographer latency
                // (measured 3.2–6 ms on this device) plus the present cost —
                // landing at vsync+12.4–15.2 ms against a 13.8 ms latch
                // deadline: a 1.4 ms margin that missed 52% of frames
                // (one slot late) during real slow scrolls. Presenting at
                // the END of the render instead still left 51% one slot
                // late — under the model THEN believed (callback 3-6 ms
                // late). That model was WRONG: the callback fires at
                // edge+0.5 ms (measured, VSYNC mon−ftn). See
                // docs/BUGS/hypotheses-120hz.md.
                //
                // RENDER-AHEAD (re-enabled under the corrected model): the
                // wake arrives ON the edge, so the held frame — presented
                // at the START of this render — lands at edge+~1.5 ms:
                // constant phase, ~4 ms of deadline margin, and render
                // SPIKES (Skia 5-10 ms) stop delaying visible frames: a
                // spike only stretches the PREPARE phase of the frame held
                // for the NEXT slot (presented at the NEXT edge+1.5 ms,
                // same phase). Cost: one slot of constant latency
                // (imperceptible).
                i_slint_renderer_skia::wgpu_30_surface::vkprobe::RENDER_AHEAD_ACTIVE
                    .store(locked, std::sync::atomic::Ordering::Relaxed);
                // PRESENT GATE: DISABLED (UI-thread sleep ate the slot
                // budget — history in hypotheses-120hz.md). Reference only.
                i_slint_renderer_skia::wgpu_30_surface::vkprobe::PRESENT_GATE_ON
                    .store(false, std::sync::atomic::Ordering::Relaxed);
                stg::S_RENDER_START.store(t2, std::sync::atomic::Ordering::Relaxed);
                // Spike classifier (hypotheses-120hz.md): CPU time inside
                // do_render. rcpu≈render ⇒ Skia/wgpu CPU work; rcpu≪render ⇒
                // blocked on the GPU/driver (queue back-pressure, fences).
                let __rc0 = stg::thread_cpu_us();
                self.window.do_render()?;
                let t3 = stg::now_us();
                stg::S_RENDER_END.store(t3, std::sync::atomic::Ordering::Relaxed);
                render_us = t3 - t2;
                __render_cpu = stg::thread_cpu_us().saturating_sub(__rc0);
            } else {
                stg::S_RENDER_END.store(0, std::sync::atomic::Ordering::Relaxed);
            }
            // RENDER_AHEAD flush (see above): on the locked → unlocked
            // transition, render once more to present the held frame.
            if prev_locked && !locked {
                self.window.pending_redraw.take();
                i_slint_renderer_skia::wgpu_30_surface::vkprobe::RENDER_AHEAD_ACTIVE
                    .store(false, std::sync::atomic::Ordering::Relaxed);
                self.window.do_render()?;
            }
            prev_locked = locked;
            if stg::IT_ON.load(std::sync::atomic::Ordering::Relaxed) {
                let first_ev = stg::S_FIRST_EV.load(std::sync::atomic::Ordering::Relaxed);
                let lv2 = stg::lv_snapshot();
                stg::log_iter(
                    t_start,
                    t_poll1 - t_start,
                    stg::S_N_EVENTS.load(std::sync::atomic::Ordering::Relaxed),
                    if first_ev == 0 { 0 } else { first_ev - t_start },
                    t2 - t_poll1,
                    stg::S_EVENT_US.load(std::sync::atomic::Ordering::Relaxed),
                    render_us,
                    animating,
                    timeout_ms,
                    lv1,
                    lv2,
                    stg::flick_snapshot(),
                    stg::input_snapshot(),
                    stg::timeout_snapshot(),
                    stg::wake_snapshot(),
                    (locked, saw_wake, pr_before, do_render),
                    __poll_cpu,
                    __render_cpu,
                );
            }
        }
        Ok(())
    }

    fn new_event_loop_proxy(&self) -> Option<Box<dyn i_slint_core::platform::EventLoopProxy>> {
        Some(Box::new(AndroidEventLoopProxy {
            event_queue: self.window.event_queue.clone(),
            waker: self.app.create_waker(),
        }))
    }

    fn set_clipboard_text(&self, text: &str, clipboard: Clipboard) {
        if clipboard == Clipboard::DefaultClipboard {
            self.window
                .java_helper
                .set_clipboard(text)
                .unwrap_or_else(|e| javahelper::print_jni_error(&self.app, e));
        }
    }

    fn clipboard_text(&self, clipboard: Clipboard) -> Option<String> {
        if clipboard == Clipboard::DefaultClipboard {
            Some(
                self.window
                    .java_helper
                    .get_clipboard()
                    .unwrap_or_else(|e| javahelper::print_jni_error(&self.app, e)),
            )
        } else {
            None
        }
    }

    fn bind_context(&self, ctx: i_slint_core::SlintContextWeak, _: i_slint_core::InternalToken) {
        let _ = self.context.set(ctx.clone());
        let ctx = ctx.upgrade().expect("bind_context called while the SlintContext is still alive");
        let color_scheme = match self
            .window
            .java_helper
            .color_scheme()
            .unwrap_or_else(|e| javahelper::print_jni_error(&self.app, e))
        {
            0x10 => i_slint_core::items::ColorScheme::Light, // UI_MODE_NIGHT_NO
            0x20 => i_slint_core::items::ColorScheme::Dark,  // UI_MODE_NIGHT_YES
            _ => i_slint_core::items::ColorScheme::Unknown,
        };
        ctx.set_color_scheme(color_scheme);
        if let Ok(accent) = self.window.java_helper.accent_color() {
            ctx.set_accent_color(accent);
        }
        if let Ok(scale) = self.window.java_helper.font_scale()
            && let Some(size) = javahelper::font_scale_to_logical_length(scale)
        {
            ctx.set_platform_default_font_size(Some(size));
        }
    }

    fn long_press_interval(&self, _: i_slint_core::InternalToken) -> Duration {
        self.window.java_helper.long_press_timeout().unwrap_or(Duration::from_millis(500))
    }
}

enum Event {
    Quit,
    Other(Box<dyn FnOnce() + Send + 'static>),
}

type EventQueue = Arc<Mutex<Vec<Event>>>;

struct AndroidEventLoopProxy {
    event_queue: EventQueue,
    waker: android_activity::AndroidAppWaker,
}

impl i_slint_core::platform::EventLoopProxy for AndroidEventLoopProxy {
    fn quit_event_loop(&self) -> Result<(), EventLoopError> {
        self.event_queue.lock().unwrap().push(Event::Quit);
        self.waker.wake();
        Ok(())
    }

    fn invoke_from_event_loop(
        &self,
        event: Box<dyn FnOnce() + Send>,
    ) -> Result<(), EventLoopError> {
        let n = crate::stg::INVK_PUSH_COUNT.fetch_add(1, std::sync::atomic::Ordering::Relaxed) + 1;
        crate::stg::log_line(&format!("INVK n={n}"));
        self.event_queue.lock().unwrap().push(Event::Other(event));
        self.waker.wake();
        Ok(())
    }
}

pub fn set_requested_graphics_api(
    requested_graphics_api: Option<i_slint_core::graphics::RequestedGraphicsAPI>,
) -> Result<(), PlatformError> {
    let Some(adapter) = CURRENT_WINDOW.with_borrow(|x| x.upgrade()) else {
        return Err(format!("On Android a graphics API for Slint can only be requested after calling slint::android::init()").into());
    };
    adapter.set_requested_graphics_api(requested_graphics_api);
    Ok(())
}