/*
 * Cage: A Wayland kiosk.
 * 
 * Copyright (C) 2018 Jente Hidskes
 *
 * See the LICENSE file accompanying this file.
 */

#define _POSIX_C_SOURCE 200112L

#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/wait.h>
#include <unistd.h>
#include <wayland-server.h>
#include <wlr/backend.h>
#include <wlr/render/wlr_renderer.h>
#include <wlr/types/wlr_compositor.h>
#include <wlr/types/wlr_data_device.h>
#include <wlr/types/wlr_output_layout.h>
#include <wlr/types/wlr_xdg_shell.h>
#include <wlr/util/log.h>

#include "output.h"
#include "seat.h"
#include "server.h"
#include "xdg_shell.h"

static bool
spawn_primary_client(char *argv[], pid_t *pid_out)
{
	pid_t pid = fork();
	if (pid == 0) {
		execvp(argv[0], argv);
		_exit(1);
	} else if (pid == -1) {
		wlr_log_errno(WLR_ERROR, "Unable to fork");
		return false;
	}

	*pid_out = pid;
	wlr_log(WLR_DEBUG, "Child process created with pid %d", pid);
	return true;
}

static int
handle_signal(int signal, void *data)
{
	struct wl_display *display = data;

	switch (signal) {
	case SIGINT:
		/* Fallthrough */
	case SIGTERM:
		wl_display_terminate(display);
		return 0;
	default:
		return 1;
	}
}

int
main(int argc, char *argv[])
{
	struct cg_server server = {0};
	struct wl_event_loop *event_loop = NULL;
	struct wlr_renderer *renderer = NULL;
	struct wlr_compositor *compositor = NULL;
	struct wlr_data_device_manager *data_device_mgr = NULL;
	struct wlr_xdg_shell *xdg_shell = NULL;
	int ret = 0;

	if (argc < 2) {
		printf("Usage: %s APPLICATION\n", argv[0]);
		return 1;
	}

#ifdef DEBUG
	wlr_log_init(WLR_DEBUG, NULL);
#else
	wlr_log_init(WLR_ERROR, NULL);
#endif

	server.wl_display = wl_display_create();
	if (!server.wl_display) {
		wlr_log(WLR_ERROR, "Cannot allocate a Wayland display");
		return 1;
	}

	event_loop = wl_display_get_event_loop(server.wl_display);
	wl_event_loop_add_signal(event_loop, SIGINT, handle_signal, &server.wl_display);
	wl_event_loop_add_signal(event_loop, SIGTERM, handle_signal, &server.wl_display);

	server.backend = wlr_backend_autocreate(server.wl_display, NULL);
	if (!server.backend) {
		wlr_log(WLR_ERROR, "Unable to create the wlroots backend");
		ret = 1;
		goto end;
	}

	renderer = wlr_backend_get_renderer(server.backend);
	wlr_renderer_init_wl_display(renderer, server.wl_display);

	server.output_layout = wlr_output_layout_create();
	if (!server.output_layout) {
		wlr_log(WLR_ERROR, "Unable to create output layout");
		ret = 1;
		goto end;
	}

	compositor = wlr_compositor_create(server.wl_display, renderer);
	if (!compositor) {
		wlr_log(WLR_ERROR, "Unable to create the wlroots compositor");
		ret = 1;
		goto end;
	}

	data_device_mgr = wlr_data_device_manager_create(server.wl_display);
	if (!data_device_mgr) {
		wlr_log(WLR_ERROR, "Unable to create the data device manager");
		ret = 1;
		goto end;
	}

	/* Configure a listener to be notified when new outputs are
	 * available on the backend. We use this only to detect the
	 * first output and ignore subsequent outputs. */
	server.new_output.notify = handle_new_output;
	wl_signal_add(&server.backend->events.new_output, &server.new_output);

	server.seat = cg_seat_create(&server);
	if (!server.seat) {
		wlr_log(WLR_ERROR, "Unable to create the seat");
		ret = 1;
		goto end;
	}

	xdg_shell = wlr_xdg_shell_create(server.wl_display);
	if (!xdg_shell) {
		wlr_log(WLR_ERROR, "Unable to create the XDG shell interface");
		ret = 1;
		goto end;
	}
	wl_list_init(&server.views);
	server.new_xdg_shell_surface.notify = handle_xdg_shell_surface_new;
	wl_signal_add(&xdg_shell->events.new_surface, &server.new_xdg_shell_surface);

	const char *socket = wl_display_add_socket_auto(server.wl_display);
	if (!socket) {
		wlr_log_errno(WLR_ERROR, "Unable to open Wayland socket");
		ret = 1;
	        goto end;
	}

	if (!wlr_backend_start(server.backend)) {
		wlr_log(WLR_ERROR, "Unable to start the wlroots backend");
		ret = 1;
		goto end;
	}

	int rc = setenv("WAYLAND_DISPLAY", socket, true);
	if (rc < 0) {
		wlr_log_errno(WLR_ERROR, "Unable to set WAYLAND_DISPLAY.",
			      "Clients may not be able to connect");
	}

	pid_t pid;
	if (!spawn_primary_client(argv + 1, &pid)) {
		ret = 1;
		goto end;
	}

	wl_display_run(server.wl_display);
	wl_display_destroy_clients(server.wl_display);

	waitpid(pid, NULL, 0);

end:
	cg_seat_destroy(server.seat);
	wlr_xdg_shell_destroy(xdg_shell);
	wlr_data_device_manager_destroy(data_device_mgr);
	wlr_compositor_destroy(compositor);
	wlr_output_layout_destroy(server.output_layout);
	wlr_backend_destroy(server.backend);
	/* This function is not null-safe, but we only ever get here
	   with a proper wl_display. */
	wl_display_destroy(server.wl_display);
	return ret;
}