#define AL_LOG_SECTION "screen"
//#define AL_LOG_ENABLE_TRACE
#include <al/log.h>
#include <al/math.h>
#include <nnwt/thread.h>
#include <nnwt/time.h>

#include "view.h"
#include "screen.h"

#define SCREEN_INVALID_TS ((u64)-1)

#define SCREEN_MOD1(scr) ((scr)->window->held_modifiers & (STELA_MOD_LCONTROL | STELA_MOD_RCONTROL))
#define SCREEN_MOD2(scr) ((scr)->window->held_modifiers & (STELA_MOD_LSHIFT | STELA_MOD_RSHIFT))
#define SCREEN_MOUSE_MOD(scr) ((scr)->flags & CAMU_SCREEN_MOUSE_MOD)

#define SCREEN_IS_DRAGGING(scr) ((scr)->flags & CAMU_SCREEN_DRAGGING)
#define SCREEN_IS_ZOOMING(scr) ((scr)->flags & CAMU_SCREEN_ZOOMING)
#define SCREEN_IS_FROZEN(scr) ((scr)->flags & CAMU_SCREEN_FROZEN)
#define SCREEN_ZOOM_MODE(scr, mode) ((scr)->flags & mode)

#define SCREEN_DEFAULT_CURSOR(scr) ((scr->fullscreen || scr->vr_emulation) ? STELA_CURSOR_HIDDEN : STELA_CURSOR_NORMAL)

#define SCREEN_LAST_CLICK_WITHIN(ns) \
    (((scr)->last_click_ts != SCREEN_INVALID_TS) && (nn_get_timestamp() - (scr)->last_click_ts <= ns))

static void should_close_callback(void *userdata)
{
    struct camu_screen *scr = (struct camu_screen *)userdata;
    scr->window->close(scr->window);
    scr->callback(scr->userdata, CAMU_SCREEN_CLOSE, NULL);
}

static void render_callback(void *userdata)
{
    struct camu_screen *scr = (struct camu_screen *)userdata;
    bool force;
    if (scr->renderer && camu_screen_tick(scr, &force)) {
        scr->renderer->render(scr->renderer, scr, force);
    }
}

static void do_resize(struct camu_screen *scr, u32 width, u32 height)
{
    if (scr->renderer) {
        scr->renderer->resize(scr->renderer, &width, &height);
    }
    al_assert(width > 0 && height > 0);
    scr->width = width;
    scr->height = height;
    struct camu_screen_video *video;
    al_array_foreach_ptr(scr->videos, i, video) {
        camu_view_calculate(&video->view, scr->width, scr->height);
    }
    // No buffers resize.
    atomic_add(u32)(&scr->force_refresh, 1, AL_ATOMIC_RELAXED);
}

static void resize_callback(void *userdata, u32 width, u32 height)
{
    struct camu_screen *scr = (struct camu_screen *)userdata;
    do_resize(scr, width, height);
}

static struct camu_view *get_view_from_mouse_pos(struct camu_screen *scr)
{
    struct camu_view *view = NULL;
    struct camu_screen_video *video;
    al_array_foreach_ptr(scr->videos, i, video) {
        if (!view) {
            view = &video->view;
            continue;
        }
        if (view->zindex < video->view.zindex) {
            view = &video->view;
        }
    }
    return view;
}

static void seek_to_percent_at_pointer(struct camu_screen *scr, f64 x)
{
    f64 percent = x / scr->width;
    percent = CLAMP(percent, 0.0, 100.0);
    scr->callback(scr->userdata, CAMU_SCREEN_PERCENT_SEEK, &percent);
}

static bool pointer_pos_callback(void *userdata, f64 x, f64 y)
{
    struct camu_screen *scr = (struct camu_screen *)userdata;
    struct camu_view *view = get_view_from_mouse_pos(scr);
    bool queue_refresh = false;
    if (SCREEN_IS_DRAGGING(scr)) {
#ifdef CAMU_SCREEN_DRAG_SEEK
        u64 now = nn_get_timestamp();
        if (view && now - scr->last_seek_ts > 100000) {
            seek_to_percent_at_pointer(scr, x);
            scr->last_seek_ts = now;
        }
#else
        if (view) {
            if (SCREEN_ZOOM_MODE(scr, CAMU_SCREEN_ZOOM_PAN_SIMPLE)) {
                f64 dx = x - scr->last_pointer_x;
                f64 dy = y - scr->last_pointer_y;
                if (camu_view_pan_simple(view, scr->width, scr->height, dx, dy)) {
                    view->mode = CAMU_VIEW_DETACHED;
                    queue_refresh = true;
                }
                if (fabs(dx) + fabs(dy) > 6.0) {
                    scr->last_click_ts = SCREEN_INVALID_TS;
                }
            }
        }
#endif
    }
    scr->last_pointer_x = x;
    scr->last_pointer_y = y;
    return queue_refresh;
}

static bool scroll_callback(void *userdata, f64 y);

static bool touch_callback(void *userdata, s32 index, u8 phase, f64 x, f64 y)
{
    // Rough testing stuff.
#define distance(x1, x2, y1, y2) sqrt(((x2 - x1) * (x2 - x1)) +  ((y2 - y1) * (y2 - y1)))
    struct camu_screen *scr = (struct camu_screen *)userdata;
    switch (phase) {
    case STELA_TOUCH_BEGAN: {
        if (index == 0) {
            scr->last_touch_x[0] = x;
            scr->last_touch_y[0] = y;
        } else if (index == 1) {
            scr->last_touch_x[1] = x;
            scr->last_touch_y[1] = y;
        }
        if (!SCREEN_IS_DRAGGING(scr)) {
            scr->flags |= CAMU_SCREEN_DRAGGING;
            scr->last_click_ts = nn_get_timestamp();
        } else if (!SCREEN_IS_ZOOMING(scr)) {
            scr->flags |= CAMU_SCREEN_ZOOMING;
            f64 lx = scr->last_touch_x[0], lx2 = scr->last_touch_x[1];
            f64 ly = scr->last_touch_y[0], ly2 = scr->last_touch_y[1];
            scr->last_distance = distance(lx, lx2, ly, ly2);
            scr->midpoint_x = (lx + lx2) / 2.0;
            scr->midpoint_y = (ly + ly2) / 2.0;
        } else if (!SCREEN_IS_FROZEN(scr)) {
            scr->flags |= CAMU_SCREEN_FROZEN;
            struct camu_view *view = get_view_from_mouse_pos(scr);
            if (view) {
                view->mode = CAMU_DEFAULT_VIEW;
                camu_view_calculate(view, scr->width, scr->height);
            }
        }
        break;
    }
    case STELA_TOUCH_MOVED: {
        // @TODO: Track current index 1 and 2. On release search for next non-0 index in mask.
        if (SCREEN_IS_FROZEN(scr)) {
            return false;
        } else if (SCREEN_IS_ZOOMING(scr)) {
            if (index == 0) {
                scr->last_touch_x[0] = x;
                scr->last_touch_y[0] = y;
            } else if (index == 1) {
                scr->last_touch_x[1] = x;
                scr->last_touch_y[1] = y;
            }
            f64 lx = scr->last_touch_x[0], lx2 = scr->last_touch_x[1];
            f64 ly = scr->last_touch_y[0], ly2 = scr->last_touch_y[1];
            f64 dist = distance(lx, lx2, ly, ly2);
            f64 mx = x = (lx + lx2) / 2.0, my = (ly + ly2) / 2.0;
            bool refresh = false;
            struct camu_view *view = get_view_from_mouse_pos(scr);
            if (view) {
                refresh |= camu_view_pan_simple(view, scr->width, scr->height, mx - scr->midpoint_x, my - scr->midpoint_y);
            }
            scr->midpoint_x = mx;
            scr->midpoint_y = my;
            scr->last_pointer_x = scr->midpoint_x;
            scr->last_pointer_y = scr->midpoint_y;
            refresh |= scroll_callback(scr, (dist - scr->last_distance) / 120.0);
            scr->last_distance = dist;
            return refresh;
        } else if (SCREEN_IS_DRAGGING(scr)) {
            if (index == 0) {
                scr->last_pointer_x = scr->last_touch_x[0];
                scr->last_pointer_y = scr->last_touch_y[0];
            } else if (index == 1) {
                scr->last_pointer_x = scr->last_touch_x[1];
                scr->last_pointer_y = scr->last_touch_y[1];
            }
            bool refresh = pointer_pos_callback(scr, x, y);
            if (index == 0) {
                scr->last_touch_x[0] = x;
                scr->last_touch_y[0] = y;
            } else if (index == 1) {
                scr->last_touch_x[1] = x;
                scr->last_touch_y[1] = y;
            }
            return refresh;
        }
        break;
    }
    case STELA_TOUCH_ENDED: {
        if (SCREEN_IS_FROZEN(scr)) {
            scr->flags &= ~CAMU_SCREEN_FROZEN;
            seek_to_percent_at_pointer(scr, x);
        } else if (SCREEN_IS_ZOOMING(scr)) {
            scr->flags &= ~CAMU_SCREEN_ZOOMING;
        } else if (SCREEN_IS_DRAGGING(scr)) {
            scr->flags &= ~CAMU_SCREEN_DRAGGING;
            if (SCREEN_LAST_CLICK_WITHIN(200000)) {
                f64 third = scr->width / 3.0;
                if (x >= third && x <= third * 2.0) {
                    scr->callback(scr->userdata, CAMU_SCREEN_TOGGLE_PAUSE, NULL);
                } else {
                    if (scr->touch_mode) {
#if CAMU_HAVE_SUBTITLES
                        scr->subtitles_enabled = !scr->subtitles_enabled;
#endif
                    } else {
                        s32 n = (x >= third) ? 1 : -1;
                        scr->callback(scr->userdata, CAMU_SCREEN_SKIP, &n);
                    }
                }
            }
        }
        break;
    }
    }
    return false;
#undef distance
}

static bool mouse_button_callback(void *userdata, u8 state, u8 button)
{
    struct camu_screen *scr = (struct camu_screen *)userdata;
    switch (button) {
    case STELA_MOUSE1:
        switch (state) {
        case STELA_BUTTON_PRESSED:
            scr->flags |= CAMU_SCREEN_DRAGGING;
            scr->window->set_cursor(scr->window, STELA_CURSOR_MOVE);
            scr->last_click_ts = nn_get_timestamp();
            break;
        case STELA_BUTTON_RELEASED:
            scr->flags &= ~CAMU_SCREEN_DRAGGING;
            scr->window->set_cursor(scr->window, SCREEN_MOUSE_MOD(scr) ? STELA_CURSOR_CROSSHAIR : SCREEN_DEFAULT_CURSOR(scr));
            if (SCREEN_LAST_CLICK_WITHIN(200000)) {
                if (SCREEN_MOD1(scr)) {
                    seek_to_percent_at_pointer(scr, scr->last_pointer_x);
                } else {
                    s32 n = (scr->last_pointer_x >= scr->width / 2.0) ? 1 : -1;
                    scr->callback(scr->userdata, CAMU_SCREEN_SKIP, &n);
                }
            }
            break;
        }
        break;
    case STELA_MOUSE2: {
        switch (state) {
        case STELA_BUTTON_PRESSED:
            scr->flags |= CAMU_SCREEN_MOUSE_MOD;
            if (scr->fullscreen && !SCREEN_IS_DRAGGING(scr)) {
                scr->window->set_cursor(scr->window, STELA_CURSOR_CROSSHAIR);
            }
            break;
        case STELA_BUTTON_RELEASED:
            scr->flags &= ~CAMU_SCREEN_MOUSE_MOD;
            if (!SCREEN_IS_DRAGGING(scr)) {
                scr->window->set_cursor(scr->window, SCREEN_DEFAULT_CURSOR(scr));
            }
            break;
        }
        break;
    }
    case STELA_MOUSE3: {
        switch (state) {
        case STELA_BUTTON_RELEASED:
            seek_to_percent_at_pointer(scr, scr->last_pointer_x);
            break;
        }
        break;
    }
    default:
        break;
    }
    return false;
}

bool scroll_callback(void *userdata, f64 y)
{
    struct camu_screen *scr = (struct camu_screen *)userdata;
    if (SCREEN_MOD1(scr)) {
        f32 change = (f32)stl_scale_scroll(y, 40.0);
        scr->callback(scr->userdata, CAMU_SCREEN_OFFSET_VOLUME, &change);
    } else {
        struct camu_view *view = get_view_from_mouse_pos(scr);
        if (view) {
            if (SCREEN_ZOOM_MODE(scr, CAMU_SCREEN_ZOOM_PAN_SIMPLE)) {
                if (camu_view_zoom_simple(view, scr->width, scr->height, scr->last_pointer_x, scr->last_pointer_y, stl_scale_scroll(y, 15.0))) {
                    view->mode = CAMU_VIEW_DETACHED;
                    return true;
                }
            } else if (SCREEN_ZOOM_MODE(scr, CAMU_SCREEN_ZOOM_FOV)) {
                camu_view_zoom_fov(view, stl_scale_scroll(y, 20.0));
            }
        }
    }
    return false;
}

static bool key_callback(void *userdata, u8 state, u16 button)
{
    struct camu_screen *scr = (struct camu_screen *)userdata;
    switch (state) {
    case STELA_BUTTON_PRESSED:
        switch (button) {
        case STELA_KEY_Q:
            scr->window->close(scr->window);
            scr->callback(scr->userdata, CAMU_SCREEN_CLOSE, NULL);
            break;
        case STELA_KEY_RIGHT:
            if (SCREEN_MOD1(scr)) {
                f64 plus_ten_seconds = 10.0;
                scr->callback(scr->userdata, CAMU_SCREEN_RELATIVE_SEEK, &plus_ten_seconds);
                break;
            }
            // fallthrough
        case STELA_KEY_TAB:
        case STELA_KEY_D: {
            s32 n = 1;
            scr->callback(scr->userdata, CAMU_SCREEN_SKIP, &n);
            break;
        }
        case STELA_KEY_LEFT:
            if (SCREEN_MOD1(scr)) {
                if (SCREEN_MOD2(scr)) {
                    f64 zero = 0.0;
                    scr->callback(scr->userdata, CAMU_SCREEN_PERCENT_SEEK, &zero);
                } else {
                    f64 minus_ten_seconds = -10.0;
                    scr->callback(scr->userdata, CAMU_SCREEN_RELATIVE_SEEK, &minus_ten_seconds);
                }
                break;
            }
            // fallthrough
        case STELA_KEY_A: {
            s32 n = -1;
            scr->callback(scr->userdata, CAMU_SCREEN_SKIP, &n);
            break;
        }
        case STELA_KEY_SPACE:
            scr->callback(scr->userdata, CAMU_SCREEN_TOGGLE_PAUSE, NULL);
            break;
        case STELA_KEY_S:
            if (SCREEN_MOD1(scr)) {
                scr->callback(scr->userdata, CAMU_SCREEN_SHUFFLE, NULL);
            } else {
#ifdef CAMU_HAVE_SUBTITLES
                scr->subtitles_enabled = !scr->subtitles_enabled;
                log_info(scr->subtitles_enabled ? "Subtitles enabled." : "Subtitles disabled.");
                return true;
#endif
            }
            break;
        case STELA_KEY_E:
            if (scr->vr_emulation) {
                if (scr->vr_emulation == CAMU_VR_180) {
                    scr->vr_left_eye = !scr->vr_left_eye;
                    log_info(scr->vr_left_eye ? "Left eye." : "Right eye.");
                }
            } else {
                scr->callback(scr->userdata, CAMU_SCREEN_RESEEK, NULL);
            }
            break;
        case STELA_KEY_M: {
            f32 volume = SCREEN_MOD1(scr) ? 1.f : -1.f;
            scr->callback(scr->userdata, CAMU_SCREEN_SET_VOLUME, &volume);
            break;
        }
        case STELA_KEY_0:
            scr->callback(scr->userdata, CAMU_SCREEN_STATUS, NULL);
            break;
#ifdef CAMU_SCREEN_DEBUG_KEY
        case STELA_KEY_P:
            scr->callback(scr->userdata, CAMU_SCREEN_DEBUG, NULL);
            break;
#endif
        case STELA_KEY_R: {
            struct camu_view *view = get_view_from_mouse_pos(scr);
            if (view) {
                if (SCREEN_MOD2(scr)) {
                    switch (view->rotation) {
                    case CAMU_VIEW_ROTATION_0:
                    case CAMU_VIEW_ROTATION_360:
                        view->rotation = CAMU_VIEW_ROTATION_90;
                        break;
                    case CAMU_VIEW_ROTATION_270:
                        view->rotation = CAMU_VIEW_ROTATION_0;
                        break;
                    case CAMU_VIEW_ROTATION_180:
                        view->rotation = CAMU_VIEW_ROTATION_270;
                        break;
                    case CAMU_VIEW_ROTATION_90:
                        view->rotation = CAMU_VIEW_ROTATION_180;
                        break;
                    }
                } else if (SCREEN_MOD1(scr)) {
                    switch (view->rotation) {
                    case CAMU_VIEW_ROTATION_0:
                    case CAMU_VIEW_ROTATION_360:
                        view->rotation = CAMU_VIEW_ROTATION_270;
                        break;
                    case CAMU_VIEW_ROTATION_270:
                        view->rotation = CAMU_VIEW_ROTATION_180;
                        break;
                    case CAMU_VIEW_ROTATION_180:
                        view->rotation = CAMU_VIEW_ROTATION_90;
                        break;
                    case CAMU_VIEW_ROTATION_90:
                        view->rotation = CAMU_VIEW_ROTATION_0;
                        break;
                    }
                } else if (scr->vr_emulation) {
                    view->fov = AL_TO_RADIANS(CAMU_DEFAULT_FOV);
                } else {
                    view->mode = CAMU_DEFAULT_VIEW;
                }
                camu_view_calculate(view, scr->width, scr->height);
                return true;
            }
            break;
        }
        case STELA_KEY_T: {
            struct camu_view *view = get_view_from_mouse_pos(scr);
            if (view) {
                scr->window->resize(scr->window, ceil(view->width * view->zoom), ceil(view->height * view->zoom));
            }
            break;
        }
        case STELA_KEY_EQUAL: {
            struct camu_view *view = get_view_from_mouse_pos(scr);
            if (view) {
                camu_view_zoom_simple(view, scr->width, scr->height, scr->width / 2.0, scr->height / 2.0, 0.05);
                return true;
            }
            break;
        }
        case STELA_KEY_MINUS: {
            struct camu_view *view = get_view_from_mouse_pos(scr);
            if (view) {
                camu_view_zoom_simple(view, scr->width, scr->height, scr->width / 2.0, scr->height / 2.0, -0.05);
                return true;
            }
            break;
        }
        case STELA_KEY_N:
            scr->scaling_disabled = !scr->scaling_disabled;
            if (scr->scaling_disabled) {
                scr->renderer->set(scr->renderer, CAMU_RENDERER_SCALING, CAMU_SCALING_NEAREST);
                log_info("Scaling filters disabled.");
            } else {
                scr->renderer->set(scr->renderer, CAMU_RENDERER_SCALING, CAMU_SCALING_DEFAULT);
                log_info("Scaling filters enabled.");
            }
            return true;
        case STELA_KEY_C:
            scr->transparent_background = !scr->transparent_background;
            if (scr->transparent_background) {
                scr->window->set_decorations(scr->window, false);
                scr->renderer->set(scr->renderer, CAMU_RENDERER_BACKGROUND, CAMU_BACKGROUND_TRANSPARENT);
                log_info("Background transparent.");
            } else {
                scr->window->set_decorations(scr->window, true);
                scr->renderer->set(scr->renderer, CAMU_RENDERER_BACKGROUND, CAMU_BACKGROUND_DEFAULT);
                log_info("Background solid.");
            }
            // Force refresh for if there's no video buffer.
            atomic_add(u32)(&scr->force_refresh, 1, AL_ATOMIC_RELAXED);
            return true;
        case STELA_KEY_V: {
            if (SCREEN_MOD1(scr)) {
                scr->vr_calibrate_x = scr->last_pointer_x / scr->width;
                scr->vr_calibrate_y = scr->last_pointer_y / scr->height;
            } else {
                struct camu_view *view = get_view_from_mouse_pos(scr);
                if (SCREEN_MOD2(scr) && scr->vr_emulation == CAMU_VR_180) {
                    scr->vr_emulation = CAMU_VR_360;
                    log_info("VR 360 degrees.");
                    break;
                }
                if (!scr->vr_emulation) {
                    if (view) view->mode = CAMU_VIEW_AUTOFIT;
                    scr->flags = (scr->flags & ~CAMU_SCREEN_ZOOM_PAN_SIMPLE) | CAMU_SCREEN_ZOOM_FOV;
                    scr->window->set_cursor(scr->window, STELA_CURSOR_HIDDEN);
                    scr->vr_emulation = SCREEN_MOD2(scr) ? CAMU_VR_360 : CAMU_VR_180;
                    log_info("VR %s degrees.", (scr->vr_emulation == CAMU_VR_180) ? "180" : "360");
                } else {
                    if (view) view->mode = CAMU_DEFAULT_VIEW;
                    scr->flags = (scr->flags & ~CAMU_SCREEN_ZOOM_FOV) | CAMU_SCREEN_ZOOM_PAN_SIMPLE;
                    scr->window->set_cursor(scr->window, STELA_CURSOR_NORMAL);
                    scr->vr_emulation = CAMU_VR_DISABLED;
                    log_info("VR disabled.");
                }
                if (view) {
                    camu_view_calculate(view, scr->width, scr->height);
                }
            }
            break;
        }
        default:
            break;
        }
        break;
    case STELA_BUTTON_RELEASED:
        break;
    default:
        break;
    }
    return false;
}

static bool key_immediate_callback(void *userdata, u8 state, u16 button)
{
    struct camu_screen *scr = (struct camu_screen *)userdata;
    switch (state) {
    case STELA_BUTTON_PRESSED:
        switch (button) {
        case STELA_KEY_F:
            scr->fullscreen = !scr->fullscreen;
            // On X11 and Wayland, MOUSE2 will be forcefully released when entering fullscreen.
            if (!SCREEN_MOUSE_MOD(scr)) {
                scr->window->set_cursor(scr->window, scr->fullscreen ? STELA_CURSOR_HIDDEN : STELA_CURSOR_NORMAL);
            }
//#ifdef STELA_API_DX11
#if 0 // Stela's window_win32 fullscreen mode (borderless) is likely more desirable here.
            scr->renderer->set(scr->renderer, CAMU_RENDERER_FULLSCREEN, scr->fullscreen);
#else
            scr->window->toggle_fullscreen(scr->window);
#endif
            return true;
        case STELA_KEY_LEFT:
            if (scr->touch_mode) {
                s32 n = -1;
                scr->callback(scr->userdata, CAMU_SCREEN_SKIP, &n);
                return true;
            }
            break;
        case STELA_KEY_RIGHT:
            if (scr->touch_mode) {
                s32 n = 1;
                scr->callback(scr->userdata, CAMU_SCREEN_SKIP, &n);
                return true;
            }
            break;
        }
        break;
    default:
        break;
    }
    return false;
}

bool camu_screen_init(struct camu_screen *scr)
{
    atomic_store(s32)(&scr->state, CAMU_SCREEN_PAUSED, AL_ATOMIC_RELAXED);
    scr->window = stl_window_create();
    scr->window->render_callback = render_callback;
    scr->window->resize_callback = resize_callback;
    scr->window->pointer_pos_callback = pointer_pos_callback;
    scr->window->touch_callback = touch_callback;
    scr->window->scroll_callback = scroll_callback;
    scr->window->mouse_button_callback = mouse_button_callback;
    scr->window->key_callback = key_callback;
    scr->window->key_immediate_callback = key_immediate_callback;
    scr->window->should_close_callback = should_close_callback;
    scr->window->userdata = scr;
    scr->renderer = NULL;
    atomic_store(u32)(&scr->force_refresh, 1, AL_ATOMIC_RELAXED);
    scr->flags = CAMU_SCREEN_ZOOM_PAN_SIMPLE;
    scr->scaling_disabled = false;
    scr->transparent_background = false;
#ifdef CAMU_HAVE_SUBTITLES
    scr->subtitles_enabled = true;
#endif
    scr->last_click_ts = SCREEN_INVALID_TS;
    scr->last_pointer_x = 0.0;
    scr->last_pointer_y = 0.0;
#ifdef CAMU_SCREEN_DRAG_SEEK
    scr->last_seek_ts = 0;
#endif
    scr->touch_mode = false;
    scr->vr_emulation = CAMU_VR_DISABLED;
    scr->vr_left_eye = false;
    scr->vr_calibrate_x = 0.5;
    scr->vr_calibrate_y = 0.5;
    al_array_init(scr->videos);
#ifdef CAMU_SCREEN_THREADED
    al_array_init(scr->add_queue);
    al_array_init(scr->rem_queue);
    atomic_store(bool)(&scr->queued, false, AL_ATOMIC_RELAXED);
    nn_mutex_init(&scr->mutex);
#endif
    return true;
}

#ifdef STELA_EVENT_BUFFER
static nn_thread_result NNWT_THREADCALL event_thread(void *userdata)
{
    struct camu_screen *scr = (struct camu_screen *)userdata;
    nn_thread_set_name("window_events");
    while (!scr->window->closed) {
        scr->window->poll(scr->window, true);
        scr->window->process_events(scr->window);
    }
    return 0;
}
#endif

bool camu_screen_create_window(struct camu_screen *scr, const char *name)
{
    u32 flags = STELA_WINDOW_VSYNC;
    if (!scr->window->create_window(scr->window, CAMU_SCREEN_WIDTH, CAMU_SCREEN_HEIGHT, flags, "", name, "camu_screen")) {
        return false;
    }
    scr->width = scr->window->width;
    scr->height = scr->window->height;
    scr->fullscreen = false;
#ifdef STELA_EVENT_BUFFER
    nn_thread_create(&scr->thread, event_thread, scr);
#endif
    return true;
}

bool camu_screen_create_renderer(struct camu_screen *scr, struct camu_renderer *renderer)
{
    scr->renderer = renderer;
    return renderer->create_renderer(renderer, &scr->width, &scr->height,
#if defined STELA_API_VULKAN
        scr->window->get_vk_proc_address,
        scr->window->vk_create_surface,
        scr->window->vk_destroy_surface,
        scr->window->vk_get_extensions,
#elif defined STELA_API_DX11
        scr->window->win32_window,
#elif defined STELA_API_OPENGL
#ifdef STELA_USE_EGL
        scr->window->egl_display,
        scr->window->egl_context,
#endif
        scr->window->get_gl_proc_address,
        scr->window->gl_loader_load,
        scr->window->gl_make_current,
        scr->window->gl_release_current,
        scr->window->gl_swap_buffers,
#endif
        scr->window);
}

static void add_buffer_internal(struct camu_screen *scr, struct camu_video_buffer *buf)
{
    struct camu_screen_video *active;
    al_array_foreach_ptr(scr->videos, i, active) {
        al_assert(active->buf != buf);
    }
    struct camu_screen_video video = { 0 };
    video.buf = buf;
    struct camu_video_format *fmt = &buf->fmt.req;
    if (buf->view.mode != CAMU_VIEW_NONE) {
        video.view = buf->view;
    } else {
        u8 rotation = buf->view.rotation;
        if (rotation != CAMU_VIEW_ROTATION_0) {
            log_info("Buffer has initial rotation of %s degrees.", camu_view_rotation_name(rotation));
        }
        camu_view_init(&video.view, fmt->width, fmt->height, rotation);
    }
    camu_view_calculate(&video.view, scr->width, scr->height);
    al_array_push(scr->videos, video);
}

static void remove_buffer_internal(struct camu_screen *scr, struct camu_video_buffer *buf)
{
    struct camu_screen_video *video;
    al_array_foreach_ptr(scr->videos, i, video) {
        if (video->buf == buf) {
            buf->view = video->view;
            al_array_remove_at(scr->videos, i);
#ifdef CAMU_SCREEN_THREADED
            atomic_store(bool)(&buf->ref, false, AL_ATOMIC_RELAXED);
#endif
            break;
        }
    }
}

#ifdef CAMU_SCREEN_THREADED
static void run_queue_internal(struct camu_screen *scr)
{
    struct camu_video_buffer *buf;
    al_array_foreach(scr->rem_queue, i, buf) {
        remove_buffer_internal(scr, buf);
    }
    scr->rem_queue.count = 0;
    // src->videos cannot be touched from outside of the render context.
    // For example, reserving space inside of screen_add_buffer() instead
    // of here would be very wrong.
    al_array_reserve(scr->videos, scr->videos.count + scr->add_queue.count);
    al_array_foreach(scr->add_queue, i, buf) {
        add_buffer_internal(scr, buf);
    }
    scr->add_queue.count = 0;
}
#endif

void camu_screen_add_buffer(struct camu_screen *scr, struct camu_video_buffer *buf)
{
#ifdef CAMU_SCREEN_THREADED
    nn_mutex_lock(&scr->mutex);
    struct camu_video_buffer *queued;
    al_array_foreach(scr->add_queue, i, queued) {
        if (queued == buf) {
            nn_mutex_unlock(&scr->mutex);
            al_assert_and_return();
        }
    }
    al_array_foreach_rev(scr->rem_queue, i, queued) {
        if (queued == buf) {
            al_array_remove_at(scr->rem_queue, i);
            bool queue_empty = scr->add_queue.count + scr->rem_queue.count == 0;
            if (queue_empty) {
                atomic_store(bool)(&scr->queued, false, AL_ATOMIC_RELAXED);
            }
            nn_mutex_unlock(&scr->mutex);
            return;
        }
    }
    al_array_push(scr->add_queue, buf);
#ifdef CAMU_SCREEN_THREADED
    atomic_store(bool)(&buf->ref, true, AL_ATOMIC_RELAXED);
#endif
    atomic_store(bool)(&scr->queued, true, AL_ATOMIC_RELAXED);
    nn_mutex_unlock(&scr->mutex);
#else
    add_buffer_internal(scr, buf);
#endif
    camu_screen_wake(scr);
}

void camu_screen_remove_buffer(struct camu_screen *scr, struct camu_video_buffer *buf)
{
#ifdef CAMU_SCREEN_THREADED
    nn_mutex_lock(&scr->mutex);
    struct camu_video_buffer *queued;
    al_array_foreach(scr->rem_queue, i, queued) {
        if (queued == buf) {
            // A sink entry that has an added video buffer (state set to BUFFER_ADDED)
            // that was previously removed (called screen_remove_buffer()), could
            // then be removed again without ever calling screen_add_buffer()
            // if that entry's audio buffer was not yet buffered.
            nn_mutex_unlock(&scr->mutex);
            return;
        }
    }
    al_array_foreach_rev(scr->add_queue, i, queued) {
        if (queued == buf) {
            al_array_remove_at(scr->add_queue, i);
#ifdef CAMU_SCREEN_THREADED
            atomic_store(bool)(&buf->ref, false, AL_ATOMIC_RELAXED);
#endif
            bool queue_empty = scr->add_queue.count + scr->rem_queue.count == 0;
            if (queue_empty) {
                atomic_store(bool)(&scr->queued, false, AL_ATOMIC_RELAXED);
            }
            nn_mutex_unlock(&scr->mutex);
            return;
        }
    }
    al_array_push(scr->rem_queue, buf);
    atomic_store(bool)(&scr->queued, true, AL_ATOMIC_RELAXED);
    nn_mutex_unlock(&scr->mutex);
#else
    remove_buffer_internal(scr, buf);
#endif
    camu_screen_wake(scr);
}

#ifdef CAMU_SCREEN_THREADED
void camu_screen_run_queue(struct camu_screen *scr)
{
    nn_mutex_lock(&scr->mutex);
    run_queue_internal(scr);
    atomic_store(bool)(&scr->queued, false, AL_ATOMIC_RELAXED);
    nn_mutex_unlock(&scr->mutex);
}

void camu_screen_clear(struct camu_screen *scr)
{
    nn_mutex_lock(&scr->mutex);
    struct camu_screen_video *video;
    al_array_foreach_ptr(scr->videos, i, video) {
        struct camu_video_buffer *buf = video->buf;
        atomic_store(bool)(&buf->ref, false, AL_ATOMIC_RELAXED);
    }
    nn_mutex_unlock(&scr->mutex);
}
#endif

void camu_screen_set_state(struct camu_screen *scr, s32 state)
{
    // If state = PAUSED, remove_buffer() relies on screen_wake().
    // Unlike mixer_pause() there are no special considerations needed for
    // the buffer queue at the point we set state to PAUSED.
    atomic_store(s32)(&scr->state, state, AL_ATOMIC_RELEASE);
    if (state == CAMU_SCREEN_PAUSED) {
        atomic_add(u32)(&scr->force_refresh, 1, AL_ATOMIC_RELAXED);
    }
}

void camu_screen_force_refresh(struct camu_screen *scr)
{
    atomic_add(u32)(&scr->force_refresh, 1, AL_ATOMIC_RELAXED);
    camu_screen_wake(scr);
}

#define CAMU_SCREEN_POLL_HZ 432

bool camu_screen_poll(struct camu_screen *scr, bool block)
{
#ifdef STELA_EVENT_BUFFER
    if (block) {
        nn_thread_sleep(NNWT_TS_FROM_USEC(1000000 / CAMU_SCREEN_POLL_HZ));
    }
    stl_window_read_events(scr->window);
#else
    scr->window->poll(scr->window, block);
    scr->window->process_events(scr->window);
#endif
#ifdef STELA_PAUSE
    return scr->window->should_refresh(scr->window);
#else
    return true;
#endif
}

bool camu_screen_tick(struct camu_screen *scr, bool *force)
{
    s32 state = atomic_load(s32)(&scr->state, AL_ATOMIC_RELAXED);
    u32 force_refresh = atomic_load(u32)(&scr->force_refresh, AL_ATOMIC_ACQUIRE);
    bool paused = !scr->vr_emulation && state == CAMU_SCREEN_PAUSED && force_refresh == 0;
    bool do_render = camu_screen_poll(scr, paused) || !paused;
    force_refresh = atomic_load(u32)(&scr->force_refresh, AL_ATOMIC_ACQUIRE);
    do_render |= force_refresh > 0;
    *force = force_refresh > 0;
    log_trace("tick (do_render: %s, force_refresh: %u).", BOOLSTR(do_render), force_refresh);
    if (force_refresh > 0) {
        atomic_sub(u32)(&scr->force_refresh, 1, AL_ATOMIC_RELEASE);
    }
    return do_render;
}

void camu_screen_wake(struct camu_screen *scr)
{
#if defined STELA_POLL_INLINE && defined STELA_PAUSE
    scr->window->wake(scr->window);
#else
    (void)scr;
#endif
}

void camu_screen_close(struct camu_screen *scr)
{
#ifdef CAMU_SCREEN_THREADED
    al_array_free(scr->add_queue);
    al_array_free(scr->rem_queue);
    nn_mutex_destroy(&scr->mutex);
#endif
    al_array_free(scr->videos);
#ifdef STELA_EVENT_BUFFER
    nn_thread_join(&scr->thread);
#endif
    if (scr->window) {
        scr->window->free(&scr->window);
    }
}