#define _POSIX_C_SOURCE 200112L
#include <time.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include "output.h"
#include "layer.h"
#include "node.h"
#include "view.h"
#include "session.h"

static void output_frame(struct wl_listener *listener, void *data)
{
    /* This function is called every time an output is ready to display a frame,
     * generally at the output's refresh rate (e.g. 60Hz). */
    struct diyac_output *output = wl_container_of(listener, output, frame);
    struct wlr_scene *scene = output->server->scene;

    struct wlr_scene_output *scene_output = wlr_scene_get_scene_output(
        scene, output->wlr_output);

    /* Render the scene if needed and commit the output */
    wlr_scene_output_commit(scene_output, NULL);

    struct timespec now;
    clock_gettime(CLOCK_MONOTONIC, &now);
    wlr_scene_output_send_frame_done(scene_output, &now);
}

static void output_request_state(struct wl_listener *listener, void *data)
{
    /* This function is called when the backend requests a new state for
     * the output. For example, Wayland and X11 backends request a new mode
     * when the output window is resized. */
    struct diyac_output *output = wl_container_of(listener, output, request_state);
    const struct wlr_output_event_request_state *event = data;
    wlr_output_commit_state(output->wlr_output, event->state);
}

static void output_destroy(struct wl_listener *listener, void *data)
{
    struct diyac_output *output = wl_container_of(listener, output, destroy);
    if(output->lock_handle)
    {
        diyac_session_unlock_output(output);
    }
    wlr_scene_node_destroy(&output->scenes.background->node);
    wlr_scene_node_destroy(&output->scenes.bottom->node);
    wlr_scene_node_destroy(&output->scenes.top->node);
    wlr_scene_node_destroy(&output->scenes.popup->node);
    wlr_scene_node_destroy(&output->scenes.overlay->node);
    wlr_scene_node_destroy(&output->scenes.session->node);


    wl_list_remove(&output->frame.link);
    wl_list_remove(&output->request_state.link);
    wl_list_remove(&output->destroy.link);
    wl_list_remove(&output->link);

    struct diyac_server* server = output->server;
    struct diyac_view * view;
    wl_list_for_each(view, &server->views, link) {
        if (view->output == output) {
            /**
            * TODO: testing this case
            */
            view->output = NULL;
            if(&server->outputs != server->outputs.next)
            {
                view->output = wl_container_of(server->outputs.next, view->output, link);
                diyac_view_update_geometry(view, false);
            }
        }
    }
    free(output);
}

void diyac_server_new_output(struct wl_listener *listener, void *data)
{
    /* This event is raised by the backend when a new output (aka a display or
     * monitor) becomes available. */
    struct diyac_server *server =
        wl_container_of(listener, server, new_output);
    struct wlr_output *wlr_output = data;

    /* Configures the output created by the backend to use our allocator
     * and our renderer. Must be done once, before commiting the output */
    wlr_output_init_render(wlr_output, server->allocator, server->renderer);

    /* The output may be disabled, switch it on. */
    struct wlr_output_state state;
    wlr_output_state_init(&state);
    wlr_output_state_set_enabled(&state, true);

    /* Some backends don't have modes. DRM+KMS does, and we need to set a mode
     * before we can use the output. The mode is a tuple of (width, height,
     * refresh rate), and each monitor supports only a specific set of modes. We
     * just pick the monitor's preferred mode, a more sophisticated compositor
     * would let the user configure it. */
    struct wlr_output_mode *mode = wlr_output_preferred_mode(wlr_output);
    if (mode != NULL)
    {
        wlr_output_state_set_mode(&state, mode);
    }

    /* Atomically applies the new output state. */
    wlr_output_commit_state(wlr_output, &state);
    wlr_output_state_finish(&state);

    /* Allocates and configures our state for this output */
    struct diyac_output *output = calloc(1, sizeof(*output));
    output->wlr_output = wlr_output;
    output->server = server;
    wlr_output->data = output;
    output->usable_area.x = 0;
    output->usable_area.y = 0;
    output->usable_area.width = wlr_output->width;
    output->usable_area.height = wlr_output->height;
    /* Sets up a listener for the frame event. */
    output->frame.notify = output_frame;
    wl_signal_add(&wlr_output->events.frame, &output->frame);

    /* Sets up a listener for the state request event. */
    output->request_state.notify = output_request_state;
    wl_signal_add(&wlr_output->events.request_state, &output->request_state);

    /* Sets up a listener for the destroy event. */
    output->destroy.notify = output_destroy;
    wl_signal_add(&wlr_output->events.destroy, &output->destroy);

    wl_list_insert(&server->outputs, &output->link);

    /*
     * Create layer-trees (background, bottom, top and overlay) and
     * a layer-popup-tree.
     */
    output->scenes.background = wlr_scene_tree_create(&server->scene->tree);
    output->scenes.bottom = wlr_scene_tree_create(&server->scene->tree);
    output->scenes.top = wlr_scene_tree_create(&server->scene->tree);
    output->scenes.popup = wlr_scene_tree_create(&server->scene->tree);
    output->scenes.overlay = wlr_scene_tree_create(&server->scene->tree);
    output->scenes.session = wlr_scene_tree_create(&server->scene->tree);

    diyac_node_descriptor_create(&output->scenes.background->node, DIYAC_NODE_TREE, NULL);
    diyac_node_descriptor_create(&output->scenes.bottom->node, DIYAC_NODE_TREE, NULL);
    diyac_node_descriptor_create(&output->scenes.top->node, DIYAC_NODE_TREE, NULL);
    diyac_node_descriptor_create(&output->scenes.popup->node, DIYAC_NODE_TREE, NULL);
    diyac_node_descriptor_create(&output->scenes.overlay->node, DIYAC_NODE_TREE, NULL);
    diyac_node_descriptor_create(&output->scenes.session->node, DIYAC_NODE_TREE, NULL);

    output->layer_tree[ZWLR_LAYER_SHELL_V1_LAYER_BACKGROUND] = output->scenes.background;
    output->layer_tree[ZWLR_LAYER_SHELL_V1_LAYER_BOTTOM] = output->scenes.bottom;
    output->layer_tree[ZWLR_LAYER_SHELL_V1_LAYER_TOP] = output->scenes.top;
    output->layer_tree[ZWLR_LAYER_SHELL_V1_LAYER_OVERLAY] = output->scenes.overlay;

    output->lock_handle = NULL;
    if(server->lock)
    {
        diyac_session_lock_output(output);
    }
    /*
     * Set the z-positions to achieve the following order (from top to
     * bottom):
     *	- session lock layer
     *	- layer-shell popups
     *	- overlay layer
     *	- top layer
     *	- views
     *	- bottom layer
     *	- background layer
     */
    wlr_scene_node_lower_to_bottom(&output->scenes.bottom->node);
    wlr_scene_node_lower_to_bottom(&output->scenes.background->node);
    wlr_scene_node_raise_to_top(&output->scenes.top->node);
    wlr_scene_node_raise_to_top(&output->scenes.overlay->node);
    wlr_scene_node_raise_to_top(&output->scenes.popup->node);
    wlr_scene_node_raise_to_top(&output->scenes.session->node);

    /* Adds this to the output layout. The add_auto function arranges outputs
     * from left-to-right in the order they appear. A more sophisticated
     * compositor would let the user configure the arrangement of outputs in the
     * layout.
     *
     * The output layout utility automatically adds a wl_output global to the
     * display, which Wayland clients can see to find out information about the
     * output (such as DPI, scale factor, manufacturer, etc).
     */
    struct wlr_output_layout_output *l_output = wlr_output_layout_add_auto(server->output_layout,
                                                                           wlr_output);
    struct wlr_scene_output *scene_output = wlr_scene_output_create(server->scene, wlr_output);
    wlr_scene_output_layout_add_output(server->scene_layout, l_output, scene_output);
}

/* returns true if usable area changed */
static bool update_usable_area(struct diyac_output *output)
{
    struct wlr_box old = output->usable_area;
    diyac_layers_arrange(output);

    return !wlr_box_equal(&old, &output->usable_area);
}

void diyac_output_update_usable_area(struct diyac_output *output)
{
    if (update_usable_area(output))
    {
        // regions_update_geometry(output);
        diyac_arrange_all_views(output->server);
        // desktop_arrange_all_views(output->server);
    }
}

struct diyac_output *diyac_output_from_cursor(struct diyac_server *server)
{
    double closest_x, closest_y;
    wlr_output_layout_closest_point(server->output_layout, NULL, server->seat.cursor->x, server->seat.cursor->y,
                                    &closest_x, &closest_y);

    struct wlr_output *output = wlr_output_layout_output_at(server->output_layout,
                                                            closest_x, closest_y);
    if (!output)
        return NULL;
    return output->data;
}

void diyac_output_usable_area(struct diyac_output *output,struct wlr_box* area)
{
    if(!area | !output)
    {
        return;
    }
    struct wlr_box box = output->usable_area;
    double ox = 0, oy = 0;
    wlr_output_layout_output_coords(output->server->output_layout,
                                    output->wlr_output, &ox, &oy);
    box.x -= ox;
    box.y -= oy;
    memcpy(area,&box,sizeof(box));
}

void diyac_output_full_area(struct diyac_output *output,struct wlr_box* area)
{
    if(!area | !output)
    {
        return;
    }
    struct wlr_box box = {0};
    wlr_output_effective_resolution(output->wlr_output,
                                        &box.width, &box.height);
    double ox = 0, oy = 0;
    wlr_output_layout_output_coords(output->server->output_layout,
                                        output->wlr_output, &ox, &oy);
    box.x -= ox;
    box.y -= oy;
    memcpy(area,&box,sizeof(box));
}