#include "wm.h"

// -----------------------------------------------------------------------
// types

enum
{
    CursorPassthrough,
    CursorMove,
    CursorResize,
};

typedef struct Keyboard Keyboard;
typedef struct View     View;
typedef struct Monitor  Monitor;
typedef struct Server   Server;
typedef struct Payload  Payload;

struct Keyboard
{
    struct wl_list link;
    struct wlr_input_device *device;
    struct {
        struct wl_listener press;
        struct wl_listener modify;
    } event;
};

struct View
{
    struct wl_list link;
    struct wlr_xdg_surface *xdg;
    struct {
        struct wl_listener map;
        struct wl_listener unmap;
        struct wl_listener destroy;
        struct wl_listener request_move;
        struct wl_listener request_resize;
    } event;
    int x, y, mapped;
};

struct Monitor
{
    struct wl_list link;
    struct wlr_output *output;
    struct {
        struct wl_listener render;
    } event;
};

struct Payload
{
    View *view;
    struct wlr_output   *output;
    struct wlr_renderer *renderer;
    struct timespec *when;
};

struct Server
{
    struct wl_display   *display;
    struct wlr_backend  *backend;
    struct wlr_renderer *renderer;

    struct {
        struct wlr_xdg_shell *xdg;
        struct wl_list list;
    } shell;

    struct {
        View *view;
        double x, y;
        struct wlr_box box;
    } grab;
    uint32 resize;

    struct {
        struct wlr_output_layout *layout;
        struct wl_list            list;
    } output;

    struct {
        struct wlr_cursor          *dot;
        struct wlr_xcursor_manager *manager;
        int                         mode;
    } cursor;

    struct {
        struct wlr_seat *seat;
        struct wl_list   keyboards;
    } input;

    struct {
        struct wl_listener new_output;
        struct wl_listener new_input;
        struct wl_listener cursor_move;
        struct wl_listener cursor_move_abs;
        struct wl_listener cursor_button;
        struct wl_listener cursor_axis;
        struct wl_listener cursor_frame;
        struct wl_listener request_cursor;
        struct wl_listener request_set_selection;
        struct wl_listener new_surface;
    } event;
};
static struct Server server;

static
void
focus(View *view, struct wlr_surface *new)
{
    struct wlr_seat        *seat;
    struct wlr_surface     *old;
    struct wlr_xdg_surface *xdg;
    struct wlr_keyboard    *keyboard;

    if(!view)
        return;

    seat = server.input.seat;
    old  = seat->keyboard_state.focused_surface;
    if(old == new)
        return;

    if(old) {
        xdg = wlr_xdg_surface_from_wlr_surface(seat->keyboard_state.focused_surface);
        wlr_xdg_toplevel_set_activated(xdg, false);
    }

    keyboard = wlr_seat_get_keyboard(seat);

    wl_list_remove(&view->link);
    wl_list_insert(&server.shell.list, &view->link);

    wlr_xdg_toplevel_set_activated(view->xdg, true);
    wlr_seat_keyboard_notify_enter(seat, view->xdg->surface,
        keyboard->keycodes, keyboard->num_keycodes, &keyboard->modifiers);
}

static
int
viewhas(View *view, double lx, double ly, struct wlr_surface **surface, double *sx, double *sy)
{
    double x, y, vsx = lx - view->x, vsy = ly - view->y;
    struct wlr_surface *find = nil;

    find = wlr_xdg_surface_surface_at(view->xdg, vsx, vsy, &x, &y);
    if(find) {
        *sx = x;
        *sy = y;
        *surface = find;
        return true;
    }

    return false;
}

static
View*
viewat(double lx, double ly, struct wlr_surface **surface, double *sx, double *sy)
{
    View *it;
    wl_list_for_each(it, &server.shell.list, link) {
        if(viewhas(it, lx, ly, surface, sx, sy))
            return it;
    }

    return nil;
}

// -----------------------------------------------------------------------
// callbacks

static
void
keymodifier(struct wl_listener *l, void *data)
{
    Keyboard *keyboard = wl_container_of(l, keyboard, event.modify);

    wlr_seat_set_keyboard(server.input.seat, keyboard->device);
    wlr_seat_keyboard_notify_modifiers(server.input.seat, &keyboard->device->keyboard->modifiers);
}

static
int
keybinding(xkb_keysym_t sym)
{
    View *current, *next;

    switch(sym) {
    case XKB_KEY_Escape:
        wl_display_terminate(server.display);
        break;
    case XKB_KEY_F1:
        /* cycle to the next view */
        if(wl_list_length(&server.shell.list) < 2) break;

        current = wl_container_of(server.shell.list.next, current, link);
        next    = wl_container_of(current->link.next, next, link);

        focus(next, next->xdg->surface);

        /* move previous view to the end of the list */
        wl_list_remove(&current->link);
        wl_list_insert(server.shell.list.prev, &current->link);
        break;
    default:
        return false;
    }
    return true;
}

static
void
keypress(struct wl_listener *l, void *data)
{
    int    i,h,n;
    uint32 keycode, modifier;
    const  xkb_keysym_t *syms;
    struct Keyboard *keyboard = wl_container_of(l, keyboard, event.press);
    struct wlr_event_keyboard_key *event = data;
    struct wlr_seat *seat = server.input.seat;

    keycode = event->keycode + 8;

    h = 0;
    n = xkb_state_key_get_syms(keyboard->device->keyboard->xkb_state, keycode, &syms);

    modifier = wlr_keyboard_get_modifiers(keyboard->device->keyboard);
    if((modifier & WLR_MODIFIER_ALT) && event->state == WL_KEYBOARD_KEY_STATE_PRESSED) {
        for(i=0; i<n; i++)
            h=keybinding(syms[i]);
    }

    if(!h) {
        wlr_seat_set_keyboard(seat, keyboard->device);
        wlr_seat_keyboard_notify_key(seat, event->time_msec,
            event->keycode, event->state);
    }
}

static
void
new_keyboard(struct wlr_input_device *device)
{
    Keyboard *keyboard;
    struct xkb_context *context;
    struct xkb_keymap  *keymap;

    context = xkb_context_new(XKB_CONTEXT_NO_FLAGS);
    keymap  = xkb_keymap_new_from_names(context, nil, XKB_KEYMAP_COMPILE_NO_FLAGS);

    wlr_keyboard_set_keymap(device->keyboard, keymap);
    wlr_keyboard_set_keymap(device->keyboard, keymap);

    xkb_keymap_unref(keymap);
    xkb_context_unref(context);

    wlr_keyboard_set_repeat_info(device->keyboard, 25, 600);

    keyboard = calloc(1, sizeof(*keyboard));
    keyboard->device = device;

    keyboard->event.modify.notify = keymodifier;
    wl_signal_add(&device->keyboard->events.modifiers, &keyboard->event.modify);
    keyboard->event.press.notify = keypress;
    wl_signal_add(&device->keyboard->events.key, &keyboard->event.press);

    wlr_seat_set_keyboard(server.input.seat, device);
    wl_list_insert(&server.input.keyboards, &keyboard->link);
}

static
void
new_pointer(struct wlr_input_device *device)
{
    wlr_cursor_attach_input_device(server.cursor.dot, device);
}

static
void
new_input(struct wl_listener *l, void *data)
{
    uint32 capability;
    struct wlr_input_device *device = data;

    switch(device->type) {
    case WLR_INPUT_DEVICE_KEYBOARD:
        new_keyboard(device);
        break;
    case WLR_INPUT_DEVICE_POINTER:
        new_pointer(device);
        /* fallthrough */
    default:
        break;
    }

    capability = WL_SEAT_CAPABILITY_POINTER;
    if(!wl_list_empty(&server.input.keyboards))
        capability |= WL_SEAT_CAPABILITY_KEYBOARD;
    wlr_seat_set_capabilities(server.input.seat, capability);
}

static
void
process_cursor_move(uint32 time) {
    server.grab.x = server.cursor.dot->x - server.grab.x;
    server.grab.y = server.cursor.dot->y - server.grab.y;
}

static
void 
process_cursor_resize(uint32 time)
{
    struct wlr_box box;
    View *view     = server.grab.view;
    double bx      = server.cursor.dot->x - server.grab.x;
    double by      = server.cursor.dot->y - server.grab.y;
    int new_left   = server.grab.box.x;
    int new_right  = server.grab.box.x + server.grab.box.width;
    int new_top    = server.grab.box.y;
    int new_bottom = server.grab.box.y + server.grab.box.height;
    int new_width, new_height;

    if(server.resize & WLR_EDGE_TOP) {
        new_top = by;
        if (new_top >= new_bottom)
            new_top = new_bottom - 1;
    }else if (server.resize & WLR_EDGE_BOTTOM) {
        new_bottom = by;
        if (new_bottom <= new_top)
            new_bottom = new_top + 1;
    }

    if(server.resize & WLR_EDGE_LEFT) {
        new_left = bx;
        if (new_left >= new_right)
            new_left = new_right - 1;
    } else if(server.resize & WLR_EDGE_RIGHT) {
        new_right = bx;
        if (new_right <= new_left)
            new_right = new_left + 1;
    }

    wlr_xdg_surface_get_geometry(view->xdg, &box);
    view->x = new_left - box.x;
    view->y = new_top  - box.y;

    new_width  = new_right  - new_left;
    new_height = new_bottom - new_top;
    wlr_xdg_toplevel_set_size(view->xdg, new_width, new_height);
}

static
void
process_cursor_motion(uint32 time)
{
    double sx, sy;
    View   *view;
    struct wlr_seat *seat;
    struct wlr_surface *surface;

    if(server.cursor.mode == CursorMove)
        return process_cursor_move(time);
    else if(server.cursor.mode == CursorResize)
        return process_cursor_resize(time);

    /* Otherwise, find the view under the pointer and send the event along. */
    seat = server.input.seat;
    surface = nil;
    view = viewat(server.cursor.dot->x, server.cursor.dot->y, &surface, &sx, &sy);
    if(!view)
        wlr_xcursor_manager_set_cursor_image(server.cursor.manager, "left_ptr", server.cursor.dot);

    if(surface) {
        wlr_seat_pointer_notify_enter(seat, surface, sx, sy);
        wlr_seat_pointer_notify_motion(seat, time, sx, sy);
    } else {
        wlr_seat_pointer_clear_focus(seat);
    }
}

static
void
cursor_move(struct wl_listener *l, void *data)
{
    struct wlr_event_pointer_motion *event = data;
    wlr_cursor_move(server.cursor.dot, event->device, event->delta_x, event->delta_y);
    process_cursor_motion(event->time_msec);
}

static
void
cursor_move_abs(struct wl_listener *l, void *data)
{
    struct wlr_event_pointer_motion_absolute *event = data;
    wlr_cursor_warp_absolute(server.cursor.dot, event->device, event->x, event->y);
    process_cursor_motion(event->time_msec);
}

static
void
cursor_button(struct wl_listener *l, void *data)
{
    View  *view;
    double sx, sy;
    struct wlr_surface *surface;
    struct wlr_event_pointer_button *event = data;

    wlr_seat_pointer_notify_button(server.input.seat,
            event->time_msec, event->button, event->state);

    view = viewat(server.cursor.dot->x, server.cursor.dot->y, &surface, &sx, &sy);
    if (event->state == WLR_BUTTON_RELEASED)
        server.cursor.mode = CursorPassthrough;
    else
        focus(view, surface);
}

static
void
cursor_axis(struct wl_listener *l, void *data)
{
    struct wlr_event_pointer_axis *event = data;
    /* Notify the client with pointer focus of the axis event. */
    wlr_seat_pointer_notify_axis(server.input.seat,
            event->time_msec, event->orientation, event->delta,
            event->delta_discrete, event->source);
}

static
void
cursor_frame(struct wl_listener *l, void *data)
{
    wlr_seat_pointer_notify_frame(server.input.seat);
}

static
void
request_cursor(struct wl_listener *l, void *data)
{
    struct wlr_seat_pointer_request_set_cursor_event *event = data;
    struct wlr_seat_client *focused_client = server.input.seat->pointer_state.focused_client;
    if(focused_client == event->seat_client)
        wlr_cursor_set_surface(server.cursor.dot, event->surface, event->hotspot_x, event->hotspot_y);
}

static
void
request_set_selection(struct wl_listener *l, void *data)
{
    struct wlr_seat_request_set_selection_event *event = data;
    wlr_seat_set_selection(server.input.seat, event->source, event->serial);
}

static
void
surface_map(struct wl_listener *l, void *data)
{
    View *view = wl_container_of(l, view, event.map);
    view->mapped = true;

    focus(view, view->xdg->surface);
}

static
void
surface_unmap(struct wl_listener *l, void *data)
{
    View *view = wl_container_of(l, view, event.unmap);
    view->mapped = false;
}

static
void
surface_destroy(struct wl_listener *l, void *data)
{
    View *view = wl_container_of(l, view, event.destroy);
    wl_list_remove(&view->link);
    free(view);
}

static
void
interactive(View *view, int mode, uint32 edges) {
    double bx, by;
    struct wlr_box box;
    struct wlr_surface *focused = server.input.seat->pointer_state.focused_surface;

    if(view->xdg->surface != focused)
        return;

    server.grab.view   = view;
    server.cursor.mode = mode;

    if(mode == CursorMove) {
        server.grab.x = server.cursor.dot->x - view->x;
        server.grab.y = server.cursor.dot->y - view->y;
    } else {
        wlr_xdg_surface_get_geometry(view->xdg, &box);

        bx = (view->x + box.x) + ((edges & WLR_EDGE_RIGHT)  ? box.width  : 0);
        by = (view->y + box.y) + ((edges & WLR_EDGE_BOTTOM) ? box.height : 0);

        server.grab.x = server.cursor.dot->x - bx;
        server.grab.y = server.cursor.dot->y - by;

        server.grab.box = box;
        server.grab.box.x += view->x;
        server.grab.box.y += view->y;

        server.resize = edges;
    }
}

static
void
toplevel_request_move(struct wl_listener *l, void *data)
{
    View *view = wl_container_of(l, view, event.request_move);
    interactive(view, CursorMove, 0);
}

static
void
toplevel_request_resize(struct wl_listener *l, void *data)
{
    struct wlr_xdg_toplevel_resize_event *event = data;
    View *view = wl_container_of(l, view, event.request_resize);
    interactive(view, CursorResize, event->edges);
}

static
void
new_surface(struct wl_listener *l, void *data)
{
    View *view;
    struct wlr_xdg_toplevel *toplevel;
    struct wlr_xdg_surface  *xdg = data;

    if(xdg->role != WLR_XDG_SURFACE_ROLE_TOPLEVEL)
        return;

    view = calloc(1, sizeof(*view));
    view->xdg = xdg;

    view->event.map.notify = surface_map;
    wl_signal_add(&xdg->events.map, &view->event.map);
    view->event.unmap.notify = surface_unmap;
    wl_signal_add(&xdg->events.unmap, &view->event.unmap);
    view->event.destroy.notify = surface_destroy;
    wl_signal_add(&xdg->events.destroy, &view->event.destroy);

    /* cotd */
    toplevel = xdg->toplevel;
    view->event.request_move.notify = toplevel_request_move;
    wl_signal_add(&toplevel->events.request_move, &view->event.request_move);
    view->event.request_resize.notify = toplevel_request_resize;
    wl_signal_add(&toplevel->events.request_resize, &view->event.request_resize);

    /* Add it to the list of views. */
    wl_list_insert(&server.shell.list, &view->link);
}

static
void
draw(struct wlr_surface *surface, int sx, int sy, void *data)
{
    float matrix[9];
    double ox, oy;
    View    *view;
    Payload *payload;
    struct wlr_box box;
    struct wlr_output *output;
    struct wlr_texture *texture;
    enum wl_output_transform transform;

    payload = data;
    view    = payload->view;
    output  = payload->output;

    texture = wlr_surface_get_texture(surface);
    if(!texture)
        return;

    ox = 0, oy = 0;
    wlr_output_layout_output_coords(server.output.layout, output, &ox, &oy);
    ox += view->x + sx, oy += view->y + sy;

    box = (struct wlr_box){
        .x = ox * output->scale,
        .y = oy * output->scale,
        .width = surface->current.width * output->scale,
        .height = surface->current.height * output->scale,
    };

    transform = wlr_output_transform_invert(surface->current.transform);
    wlr_matrix_project_box(matrix, &box, transform, 0, output->transform_matrix);

    wlr_render_texture_with_matrix(payload->renderer, texture, matrix, 1);
    wlr_surface_send_frame_done(surface, payload->when);
}

static
void
render(struct wl_listener *l, void *data)
{
    int width, height;
    struct timespec now;
    View *view;
    Monitor *monitor;
    struct wlr_renderer *renderer;
    float color[4] = {0.3, 0.3, 0.3, 1.0};

    monitor  = wl_container_of(l, monitor, event.render);
    renderer = server.renderer;
    clock_gettime(CLOCK_MONOTONIC, &now);

    if(!wlr_output_attach_render(monitor->output, nil))
        return;

    wlr_output_effective_resolution(monitor->output, &width, &height);

    /* start of rendering kernel */
    wlr_renderer_begin(renderer, width, height);
    wlr_renderer_clear(renderer, color);

    wl_list_for_each_reverse(view, &server.shell.list, link) {
        if(!view->mapped)
            continue;

        Payload payload = {
            .output   = monitor->output,
            .view     = view,
            .renderer = renderer,
            .when     = &now,
        };

        wlr_xdg_surface_for_each_surface(view->xdg, draw, &payload);
    }

    wlr_output_render_software_cursors(monitor->output, nil);

    wlr_renderer_end(renderer);
    wlr_output_commit(monitor->output);
}

static
void
new_output(struct wl_listener *l, void *data)
{
    struct wlr_output_mode *mode;
    struct Monitor         *monitor;
    struct wlr_output      *output = data;

    if (!wl_list_empty(&output->modes)) {
        mode = wlr_output_preferred_mode(output);
        wlr_output_set_mode(output, mode);
        wlr_output_enable(output, true);
        if (!wlr_output_commit(output)) {
            return;
        }
    }

    monitor = calloc(1, sizeof(*monitor));
    monitor->output = output;

    monitor->event.render.notify = render;
    wl_signal_add(&output->events.frame, &monitor->event.render);
    wl_list_insert(&server.output.list, &monitor->link);

    wlr_output_layout_add_auto(server.output.layout, output);
}

// -----------------------------------------------------------------------
// main point of entry

int
main(int argc, char *argv[])
{
    char *socket;

    wlr_log_init(WLR_DEBUG, nil);

    server.display  = wl_display_create();
    server.backend  = wlr_backend_autocreate(server.display);
    server.renderer = wlr_backend_get_renderer(server.backend);

    wlr_renderer_init_wl_display(server.renderer, server.display);

    wlr_compositor_create(server.display, server.renderer);
    wlr_data_device_manager_create(server.display);

    server.output.layout = wlr_output_layout_create();

    wl_list_init(&server.output.list);
    server.event.new_output.notify = new_output;
    wl_signal_add(&server.backend->events.new_output, &server.event.new_output);

    wl_list_init(&server.shell.list);
    server.shell.xdg = wlr_xdg_shell_create(server.display);
    server.event.new_surface.notify = new_surface;
    wl_signal_add(&server.shell.xdg->events.new_surface, &server.event.new_surface);

    server.cursor.dot = wlr_cursor_create();
    wlr_cursor_attach_output_layout(server.cursor.dot, server.output.layout);

    server.cursor.manager = wlr_xcursor_manager_create(nil, 24);
    wlr_xcursor_manager_load(server.cursor.manager, 1);

    server.event.cursor_move.notify = cursor_move;
    wl_signal_add(&server.cursor.dot->events.motion, &server.event.cursor_move);
    server.event.cursor_move_abs.notify = cursor_move_abs;
    wl_signal_add(&server.cursor.dot->events.motion_absolute, &server.event.cursor_move_abs);
    server.event.cursor_button.notify = cursor_button;
    wl_signal_add(&server.cursor.dot->events.button, &server.event.cursor_button);
    server.event.cursor_axis.notify = cursor_axis;
    wl_signal_add(&server.cursor.dot->events.axis, &server.event.cursor_axis);
    server.event.cursor_frame.notify = cursor_frame;
    wl_signal_add(&server.cursor.dot->events.frame, &server.event.cursor_frame);

    wl_list_init(&server.input.keyboards);
    server.event.new_input.notify = new_input;
    wl_signal_add(&server.backend->events.new_input, &server.event.new_input);

    server.input.seat = wlr_seat_create(server.display, "seat0");

    server.event.request_cursor.notify = request_cursor;
    wl_signal_add(&server.input.seat->events.request_set_cursor, &server.event.request_cursor);
    server.event.request_set_selection.notify = request_set_selection;
    wl_signal_add(&server.input.seat->events.request_set_selection, &server.event.request_set_selection);

    if(!(socket=(char*)wl_display_add_socket_auto(server.display))) {
        wlr_backend_destroy(server.backend);
        return 1;
    }

    if(!(wlr_backend_start(server.backend))) {
        wlr_backend_destroy(server.backend);
        wl_display_destroy(server.display);
        return 1;
    }

    setenv("WAYLAND_DISPLAY", socket, true);
    wlr_log(WLR_INFO, "Running Wayland compositor on WAYLAND_DISPLAY=%s", socket);

    /* start loop */
    wl_display_run(server.display);
    /* end loop */

    wl_display_destroy_clients(server.display);
    wl_display_destroy(server.display);
    return 0;
}