#define _POSIX_C_SOURCE 200809L
#include <assert.h>
#include <getopt.h>
#include <string.h>
#include <wordexp.h>
#include "log.h"
#include "stringop.h"
#include "swaybg.h"
#include "util.h"
#include "xdg-output-unstable-v1-client-protocol.h"

void sway_terminate(void) {
	exit(0);
}

static void destroy_surface(struct swaybg_surface *surface) {
	wl_list_remove(&surface->link);
	if (surface->layer_surface != NULL) {
		zwlr_layer_surface_v1_destroy(surface->layer_surface);
	}
	if (surface->surface != NULL) {
		wl_surface_destroy(surface->surface);
	}
	destroy_buffer(&surface->buffers[0]);
	destroy_buffer(&surface->buffers[1]);
	wl_output_destroy(surface->output);
	free(surface);
}

static const struct zwlr_layer_surface_v1_listener layer_surface_listener;

static cairo_surface_t *select_image(struct swaybg_state *state,
		struct swaybg_surface *surface);

static void create_layer_surface(struct swaybg_surface *surface) {
	struct swaybg_state *state = surface->state;

	surface->image = select_image(state, surface);

	surface->surface = wl_compositor_create_surface(state->compositor);
	assert(surface->surface);

	surface->layer_surface = zwlr_layer_shell_v1_get_layer_surface(
		state->layer_shell, surface->surface, surface->output,
		ZWLR_LAYER_SHELL_V1_LAYER_BACKGROUND, "wallpaper");
	assert(surface->layer_surface);

	zwlr_layer_surface_v1_set_size(surface->layer_surface, 0, 0);
	zwlr_layer_surface_v1_set_anchor(surface->layer_surface,
		ZWLR_LAYER_SURFACE_V1_ANCHOR_TOP |
		ZWLR_LAYER_SURFACE_V1_ANCHOR_RIGHT |
		ZWLR_LAYER_SURFACE_V1_ANCHOR_BOTTOM |
		ZWLR_LAYER_SURFACE_V1_ANCHOR_LEFT);
	zwlr_layer_surface_v1_set_exclusive_zone(surface->layer_surface, -1);
	zwlr_layer_surface_v1_add_listener(surface->layer_surface,
		&layer_surface_listener, surface);

	struct wl_region *input_region =
		wl_compositor_create_region(state->compositor);
	wl_surface_set_input_region(surface->surface, input_region);
	wl_region_destroy(input_region);

	wl_surface_commit(surface->surface);
}

static void layer_surface_configure(void *data,
		struct zwlr_layer_surface_v1 *layer_surface,
		uint32_t serial, uint32_t width, uint32_t height) {
	struct swaybg_surface *surface = data;
	surface->width = width;
	surface->height = height;
	zwlr_layer_surface_v1_ack_configure(layer_surface, serial);
	render_surface(surface);
}

static void layer_surface_closed(void *data,
		struct zwlr_layer_surface_v1 *layer_surface) {
	struct swaybg_surface *surface = data;
	destroy_surface(surface);
}

static const struct zwlr_layer_surface_v1_listener layer_surface_listener = {
	.configure = layer_surface_configure,
	.closed = layer_surface_closed,
};

static void handle_wl_output_geometry(void *data, struct wl_output *output,
		int32_t x, int32_t y, int32_t width_mm, int32_t height_mm,
		int32_t subpixel, const char *make, const char *model,
		int32_t transform) {
	// Who cares
}

static void handle_wl_output_mode(void *data, struct wl_output *output,
		uint32_t flags, int32_t width, int32_t height, int32_t refresh) {
	// Who cares
}

static void handle_wl_output_done(void *data, struct wl_output *output) {
	// Who cares
}

static void handle_wl_output_scale(void *data, struct wl_output *output,
		int32_t factor) {
	struct swaybg_surface *surface = data;
	surface->scale = factor;
	if (surface->state->run_display) {
		render_surface(surface);
	}
}

struct wl_output_listener _wl_output_listener = {
	.geometry = handle_wl_output_geometry,
	.mode = handle_wl_output_mode,
	.done = handle_wl_output_done,
	.scale = handle_wl_output_scale,
};

static void handle_xdg_output_logical_size(void *data, struct zxdg_output_v1 *output,
		int width, int height) {
	// Who cares
}

static void handle_xdg_output_logical_position(void *data,
		struct zxdg_output_v1 *output, int x, int y) {
	// Who cares
}

static void handle_xdg_output_name(void *data, struct zxdg_output_v1 *output,
		const char *name) {
	struct swaybg_surface *surface = data;
	surface->xdg_output = output;
	surface->output_name = strdup(name);
}

static void handle_xdg_output_description(void *data, struct zxdg_output_v1 *output,
		const char *description) {
	// Who cares
}

static void handle_xdg_output_done(void *data, struct zxdg_output_v1 *output) {
	// Who cares
}

struct zxdg_output_v1_listener _xdg_output_listener = {
	.logical_position = handle_xdg_output_logical_position,
	.logical_size = handle_xdg_output_logical_size,
	.done = handle_xdg_output_done,
	.name = handle_xdg_output_name,
	.description = handle_xdg_output_description,
};

static void handle_global(void *data, struct wl_registry *registry,
		uint32_t name, const char *interface, uint32_t version) {
	struct swaybg_state *state = data;
	if (strcmp(interface, wl_compositor_interface.name) == 0) {
		state->compositor = wl_registry_bind(registry, name,
			&wl_compositor_interface, 3);
	} else if (strcmp(interface, wl_shm_interface.name) == 0) {
		state->shm = wl_registry_bind(registry, name,
			&wl_shm_interface, 1);
	} else if (strcmp(interface, zwlr_layer_shell_v1_interface.name) == 0) {
		state->layer_shell = wl_registry_bind(
			registry, name, &zwlr_layer_shell_v1_interface, 1);
	} else if (strcmp(interface, zxdg_output_manager_v1_interface.name) == 0) {
		state->zxdg_output_manager = wl_registry_bind(
			registry, name, &zxdg_output_manager_v1_interface, 2);
	} else if (strcmp(interface, wl_output_interface.name) == 0) {
		struct swaybg_surface *surface =
			calloc(1, sizeof(struct swaybg_surface));
		surface->state = state;
		surface->output = wl_registry_bind(registry, name,
			&wl_output_interface, 3);
		surface->output_global_name = name;
		wl_output_add_listener(surface->output, &_wl_output_listener, surface);
		wl_list_insert(&state->surfaces, &surface->link);

		if (state->run_display) {
			create_layer_surface(surface);
			wl_display_roundtrip(state->display);
		}
	}
}

static void handle_global_remove(void *data, struct wl_registry *registry,
		uint32_t name) {
	struct swaybg_state *state = data;
	struct swaybg_surface *surface;
	wl_list_for_each(surface, &state->surfaces, link) {
		if (surface->output_global_name == name) {
			destroy_surface(surface);
			break;
		}
	}
}

static const struct wl_registry_listener registry_listener = {
	.global = handle_global,
	.global_remove = handle_global_remove,
};

static cairo_surface_t *select_image(struct swaybg_state *state,
		struct swaybg_surface *surface) {
	struct swaybg_image *image;
	cairo_surface_t *default_image = NULL;
	wl_list_for_each(image, &state->images, link) {
		if (lenient_strcmp(image->output_name, surface->output_name) == 0) {
			return image->cairo_surface;
		} else if (!image->output_name) {
			default_image = image->cairo_surface;
		}
	}
	return default_image;
}

static void load_image(char *arg, struct swaybg_state *state) {
	// [<output>:]<path>
	struct swaybg_image *image = calloc(1, sizeof(struct swaybg_image));
	char *separator = strchr(arg, ':');
	if (separator) {
		*separator = '\0';
		image->output_name = strdup(arg);
		image->path = strdup(separator + 1);
	} else {
		image->output_name = NULL;
		image->path = strdup(arg);
	}

	bool exists = false;
	struct swaybg_image *iter_image;
	wl_list_for_each(iter_image, &state->images, link) {
		if (lenient_strcmp(iter_image->output_name, image->output_name) == 0) {
			exists = true;
			break;
		}
	}
	if (exists) {
		if (image->output_name) {
			wlr_log(WLR_ERROR, "Multiple images defined for output %s",
				image->output_name);
		} else {
			wlr_log(WLR_ERROR, "Multiple default images defined");
		}
	}

	// Bash doesn't replace the ~ with $HOME if the output name is supplied
	wordexp_t p;
	if (wordexp(image->path, &p, 0) == 0) {
		free(image->path);
		image->path = strdup(p.we_wordv[0]);
		wordfree(&p);
	}

	// Load the actual image
	image->cairo_surface = load_background_image(image->path);
	if (!image->cairo_surface) {
		free(image);
		return;
	}
	wl_list_insert(&state->images, &image->link);
	state->args.mode = BACKGROUND_MODE_FILL;
	wlr_log(WLR_DEBUG, "Loaded image %s for output %s",
			image->path, image->output_name ? image->output_name : "*");
}

static const char usage[] =
	"Usage: swaybg [options...]\n"
	"\n"
	"  -h, --help                     Show help message and quit.\n"
	"  -c, --color <rrggbb[aa]>       Turn the screen into the given color instead of white.\n"
	"  -s, --scaling                  Scaling mode: stretch, fill, fit, center, tile.\n"
	"  -v, --version                  Show the version number and quit.\n"
	"  -i, --image [<output>:]<path>  Display the given image.\n";

int main(int argc, char *argv[]) {
	static const struct option long_options[] = {
		{"help", no_argument, NULL, 'h'},
		{"color", required_argument, NULL, 'c'},
		{"image", required_argument, NULL, 'i'},
		{"scaling", required_argument, NULL, 's'},
		{"version", no_argument, NULL, 'v'},
		{"socket", required_argument, NULL, 'p'},
		{0}
	};

	struct swaybg_state state = {0};
	state.args = (struct swaybg_args){
		.mode = BACKGROUND_MODE_SOLID_COLOR,
		.color = 0xFFFFFFFF,
	};
	wl_list_init(&state.images);
	wl_list_init(&state.surfaces);

	wlr_log_init(WLR_DEBUG, NULL);

	int c;
	while (1) {
		int option_index = 0;
		c = getopt_long(argc, argv, "hc:i:s:v", long_options, &option_index);
		if (c == -1) {
			break;
		}
		switch (c) {
		case 'c': {
			state.args.color = parse_color(optarg);
			state.args.mode = BACKGROUND_MODE_SOLID_COLOR;
			break;
		}
		case 'i':
			load_image(optarg, &state);
			break;
		case 's':
			state.args.mode = parse_background_mode(optarg);
			if (state.args.mode == BACKGROUND_MODE_INVALID) {
				return 1;
			}
			break;
		case 't':
			state.args.mode = BACKGROUND_MODE_TILE;
			break;
		case 'v':
#if defined SWAY_GIT_VERSION && defined SWAY_GIT_BRANCH && defined SWAY_VERSION_DATE
			fprintf(stdout, "swaybg version %s (%s, branch \"%s\")\n",
					SWAY_GIT_VERSION, SWAY_VERSION_DATE, SWAY_GIT_BRANCH);
#else
			fprintf(stdout, "version unknown\n");
#endif
			return 0;
		default:
			fprintf(stderr, "%s", usage);
			return 1;
		}
	}

	state.display = wl_display_connect(NULL);
	assert(state.display);

	struct wl_registry *registry = wl_display_get_registry(state.display);
	wl_registry_add_listener(registry, &registry_listener, &state);
	wl_display_roundtrip(state.display);
	assert(state.compositor && state.layer_shell && state.shm);

	if (state.zxdg_output_manager) {
		struct swaybg_surface *surface;
		wl_list_for_each(surface, &state.surfaces, link) {
			surface->xdg_output = zxdg_output_manager_v1_get_xdg_output(
						state.zxdg_output_manager, surface->output);
			zxdg_output_v1_add_listener(
					surface->xdg_output, &_xdg_output_listener, surface);
		}
		wl_display_roundtrip(state.display);
	} else {
		wlr_log(WLR_INFO, "Compositor does not support zxdg output manager, "
				"images assigned to named outputs will not work");
	}

	struct swaybg_surface *surface;
	wl_list_for_each(surface, &state.surfaces, link) {
		create_layer_surface(surface);
	}

	state.run_display = true;
	while (wl_display_dispatch(state.display) != -1 && state.run_display) {
		// This space intentionally left blank
	}
	return 0;
}