#include <assert.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <unistd.h>

#include <wayland-client.h>

#include <wlr/interfaces/wlr_output.h>
#include <wlr/render/wlr_renderer.h>
#include <wlr/types/wlr_matrix.h>
#include <wlr/util/log.h>

#include "backend/wayland.h"
#include "util/signal.h"
#include "xdg-decoration-unstable-v1-client-protocol.h"
#include "xdg-shell-client-protocol.h"

static struct wlr_wl_output *get_wl_output_from_output(
		struct wlr_output *wlr_output) {
	assert(wlr_output_is_wl(wlr_output));
	return (struct wlr_wl_output *)wlr_output;
}

static struct wl_callback_listener frame_listener;

static void surface_frame_callback(void *data, struct wl_callback *cb,
		uint32_t time) {
	struct wlr_wl_output *output = data;
	assert(output);
	wl_callback_destroy(cb);
	output->frame_callback = NULL;

	wlr_output_send_frame(&output->wlr_output);
}

static struct wl_callback_listener frame_listener = {
	.done = surface_frame_callback
};

static bool output_set_custom_mode(struct wlr_output *wlr_output,
		int32_t width, int32_t height, int32_t refresh) {
	struct wlr_wl_output *output = get_wl_output_from_output(wlr_output);
	wlr_egl_swap_buffers(&output->backend->egl, output->egl_surface, NULL);
	wl_egl_window_resize(output->egl_window, width, height, 0, 0);
	wlr_output_update_custom_mode(&output->wlr_output, width, height, 0);

	return true;
}

static bool output_attach_render(struct wlr_output *wlr_output,
		int *buffer_age) {
	struct wlr_wl_output *output =
		get_wl_output_from_output(wlr_output);
	return wlr_egl_make_current(&output->backend->egl, output->egl_surface,
		buffer_age);
}

static bool output_cursor_try_set_size(struct wlr_output *wlr_output,
		int *x, int *y) {
	struct wlr_wl_output *output =
		get_wl_output_from_output(wlr_output);
	struct wlr_wl_backend *backend = output->backend;

	if (output->cursor.surface) {
		wl_egl_window_resize(output->cursor.native, *x, *y, 0, 0);
		return true;
	}

	output->cursor.surface =
		wl_compositor_create_surface(backend->compositor);

	output->cursor.native =
		wl_egl_window_create(output->cursor.surface, *x, *y);
	if (!output->cursor.native) {
		goto error_surface;
	}

	output->cursor.egl =
		wlr_egl_create_surface(&backend->egl, output->cursor.native);
	if (!output->cursor.egl) {
		goto error_native;
	}

	return true;

error_native:
	wl_egl_window_destroy(output->cursor.native);
	output->cursor.native = NULL;
error_surface:
	wl_surface_destroy(output->cursor.surface);
	output->cursor.surface = NULL;
	return false;
}

static bool output_cursor_attach_render(struct wlr_output *wlr_output,
		int *buffer_age) {
	struct wlr_wl_output *output =
		get_wl_output_from_output(wlr_output);
	assert(output->cursor.surface);
	return wlr_egl_make_current(&output->backend->egl,
		output->cursor.egl, buffer_age);
}

static bool output_cursor_commit(struct wlr_output *wlr_output) {
	struct wlr_wl_output *output =
		get_wl_output_from_output(wlr_output);
	struct wlr_output_cursor *cursor = &wlr_output->cursor_pending;

	if (cursor->committed & WLR_OUTPUT_CURSOR_BUFFER) {
		if (!wlr_egl_swap_buffers(&output->backend->egl,
				output->cursor.egl, NULL)) {
			return false;
		}
	}

	if (cursor->committed & WLR_OUTPUT_CURSOR_POS) {
		output->cursor.hotspot_x = cursor->hotspot_x;
		output->cursor.hotspot_y = cursor->hotspot_y;
	}

	if (cursor->committed & WLR_OUTPUT_CURSOR_ENABLE) {
		output->cursor.enabled = cursor->enabled;
	}

	if (output->cursor.enabled) {
		update_wl_output_cursor(output);
	} else {
		wl_surface_attach(output->cursor.surface, NULL, 0, 0);
		wl_surface_commit(output->cursor.surface);
	}

	return true;
}

static bool output_commit(struct wlr_output *wlr_output) {
	struct wlr_wl_output *output =
		get_wl_output_from_output(wlr_output);

	if (output->frame_callback != NULL) {
		wlr_log(WLR_ERROR, "Skipping buffer swap");
		return false;
	}

	output->frame_callback = wl_surface_frame(output->surface);
	wl_callback_add_listener(output->frame_callback, &frame_listener, output);

	pixman_region32_t *damage = NULL;
	if (wlr_output->pending.committed & WLR_OUTPUT_STATE_DAMAGE) {
		damage = &wlr_output->pending.damage;
	}

	if (!wlr_egl_swap_buffers(&output->backend->egl,
			output->egl_surface, damage)) {
		return false;
	}

	// TODO: if available, use the presentation-time protocol
	wlr_output_send_present(wlr_output, NULL);
	return true;
}

static void output_destroy(struct wlr_output *wlr_output) {
	struct wlr_wl_output *output = get_wl_output_from_output(wlr_output);
	if (output == NULL) {
		return;
	}

	wl_list_remove(&output->link);

	if (output->cursor.egl) {
		wlr_egl_destroy_surface(&output->backend->egl, output->cursor.egl);
	}
	if (output->cursor.native) {
		wl_egl_window_destroy(output->cursor.native);
	}
	if (output->cursor.surface) {
		wl_surface_destroy(output->cursor.surface);
	}

	if (output->frame_callback) {
		wl_callback_destroy(output->frame_callback);
	}

	wlr_egl_destroy_surface(&output->backend->egl, output->egl_surface);
	wl_egl_window_destroy(output->egl_window);
	if (output->zxdg_toplevel_decoration_v1) {
		zxdg_toplevel_decoration_v1_destroy(output->zxdg_toplevel_decoration_v1);
	}
	xdg_toplevel_destroy(output->xdg_toplevel);
	xdg_surface_destroy(output->xdg_surface);
	wl_surface_destroy(output->surface);
	free(output);
}

void update_wl_output_cursor(struct wlr_wl_output *output) {
	if (output->backend->pointer && output->enter_serial) {
		wl_pointer_set_cursor(output->backend->pointer,
			output->enter_serial, output->cursor.surface,
			output->cursor.hotspot_x, output->cursor.hotspot_y);
	}
}

static bool output_schedule_frame(struct wlr_output *wlr_output) {
	struct wlr_wl_output *output = get_wl_output_from_output(wlr_output);

	if (output->frame_callback != NULL) {
		wlr_log(WLR_ERROR, "Skipping frame scheduling");
		return true;
	}

	output->frame_callback = wl_surface_frame(output->surface);
	wl_callback_add_listener(output->frame_callback, &frame_listener, output);
	wl_surface_commit(output->surface);
	return true;
}

static const struct wlr_output_impl output_impl = {
	.set_custom_mode = output_set_custom_mode,
	.destroy = output_destroy,
	.cursor_try_set_size = output_cursor_try_set_size,
	.cursor_attach_render = output_cursor_attach_render,
	.cursor_commit = output_cursor_commit,
	.attach_render = output_attach_render,
	.commit = output_commit,
	.schedule_frame = output_schedule_frame,
};

bool wlr_output_is_wl(struct wlr_output *wlr_output) {
	return wlr_output->impl == &output_impl;
}

static void xdg_surface_handle_configure(void *data,
		struct xdg_surface *xdg_surface, uint32_t serial) {
	struct wlr_wl_output *output = data;
	assert(output && output->xdg_surface == xdg_surface);

	xdg_surface_ack_configure(xdg_surface, serial);

	// nothing else?
}

static struct xdg_surface_listener xdg_surface_listener = {
	.configure = xdg_surface_handle_configure,
};

static void xdg_toplevel_handle_configure(void *data,
		struct xdg_toplevel *xdg_toplevel,
		int32_t width, int32_t height, struct wl_array *states) {
	struct wlr_wl_output *output = data;
	assert(output && output->xdg_toplevel == xdg_toplevel);

	if (width == 0 || height == 0) {
		return;
	}
	// loop over states for maximized etc?
	output_set_custom_mode(&output->wlr_output, width, height, 0);
}

static void xdg_toplevel_handle_close(void *data,
		struct xdg_toplevel *xdg_toplevel) {
	struct wlr_wl_output *output = data;
	assert(output && output->xdg_toplevel == xdg_toplevel);

	wlr_output_destroy((struct wlr_output *)output);
}

static struct xdg_toplevel_listener xdg_toplevel_listener = {
	.configure = xdg_toplevel_handle_configure,
	.close = xdg_toplevel_handle_close,
};

struct wlr_output *wlr_wl_output_create(struct wlr_backend *wlr_backend) {
	struct wlr_wl_backend *backend = get_wl_backend_from_backend(wlr_backend);
	if (!backend->started) {
		++backend->requested_outputs;
		return NULL;
	}

	struct wlr_wl_output *output;
	if (!(output = calloc(sizeof(struct wlr_wl_output), 1))) {
		wlr_log(WLR_ERROR, "Failed to allocate wlr_wl_output");
		return NULL;
	}
	wlr_output_init(&output->wlr_output, &backend->backend, &output_impl,
		backend->local_display);
	struct wlr_output *wlr_output = &output->wlr_output;

	wlr_output_update_custom_mode(wlr_output, 1280, 720, 0);
	strncpy(wlr_output->make, "wayland", sizeof(wlr_output->make));
	strncpy(wlr_output->model, "wayland", sizeof(wlr_output->model));
	snprintf(wlr_output->name, sizeof(wlr_output->name), "WL-%zd",
		++backend->last_output_num);

	output->backend = backend;

	output->surface = wl_compositor_create_surface(backend->compositor);
	if (!output->surface) {
		wlr_log_errno(WLR_ERROR, "Could not create output surface");
		goto error;
	}
	wl_surface_set_user_data(output->surface, output);
	output->xdg_surface =
		xdg_wm_base_get_xdg_surface(backend->xdg_wm_base, output->surface);
	if (!output->xdg_surface) {
		wlr_log_errno(WLR_ERROR, "Could not get xdg surface");
		goto error;
	}
	output->xdg_toplevel =
		xdg_surface_get_toplevel(output->xdg_surface);
	if (!output->xdg_toplevel) {
		wlr_log_errno(WLR_ERROR, "Could not get xdg toplevel");
		goto error;
	}

	if (backend->zxdg_decoration_manager_v1) {
		output->zxdg_toplevel_decoration_v1 =
			zxdg_decoration_manager_v1_get_toplevel_decoration(
			backend->zxdg_decoration_manager_v1, output->xdg_toplevel);
		if (!output->zxdg_toplevel_decoration_v1) {
			wlr_log_errno(WLR_ERROR, "Could not get xdg toplevel decoration");
			goto error;
		}
		zxdg_toplevel_decoration_v1_set_mode(output->zxdg_toplevel_decoration_v1,
			ZXDG_TOPLEVEL_DECORATION_V1_MODE_SERVER_SIDE);
	}

	wlr_wl_output_set_title(wlr_output, NULL);

	xdg_toplevel_set_app_id(output->xdg_toplevel, "wlroots");
	xdg_surface_add_listener(output->xdg_surface,
			&xdg_surface_listener, output);
	xdg_toplevel_add_listener(output->xdg_toplevel,
			&xdg_toplevel_listener, output);
	wl_surface_commit(output->surface);

	output->egl_window = wl_egl_window_create(output->surface,
			wlr_output->width, wlr_output->height);
	output->egl_surface = wlr_egl_create_surface(&backend->egl,
		output->egl_window);

	wl_display_roundtrip(output->backend->remote_display);

	// start rendering loop per callbacks by rendering first frame
	if (!wlr_egl_make_current(&output->backend->egl, output->egl_surface,
			NULL)) {
		goto error;
	}

	wlr_renderer_begin(backend->renderer, wlr_output->width, wlr_output->height);
	wlr_renderer_clear(backend->renderer, (float[]){ 1.0, 1.0, 1.0, 1.0 });
	wlr_renderer_end(backend->renderer);

	output->frame_callback = wl_surface_frame(output->surface);
	wl_callback_add_listener(output->frame_callback, &frame_listener, output);

	if (!wlr_egl_swap_buffers(&output->backend->egl, output->egl_surface,
			NULL)) {
		goto error;
	}

	wl_list_insert(&backend->outputs, &output->link);
	wlr_output_update_enabled(wlr_output, true);

	wlr_signal_emit_safe(&backend->backend.events.new_output, wlr_output);

	if (backend->pointer != NULL) {
		create_wl_pointer(backend->pointer, output);
	}

	return wlr_output;

error:
	wlr_output_destroy(&output->wlr_output);
	return NULL;
}

void wlr_wl_output_set_title(struct wlr_output *output, const char *title) {
	struct wlr_wl_output *wl_output = get_wl_output_from_output(output);

	char wl_title[32];
	if (title == NULL) {
		if (snprintf(wl_title, sizeof(wl_title), "wlroots - %s", output->name) <= 0) {
			return;
		}
		title = wl_title;
	}

	xdg_toplevel_set_title(wl_output->xdg_toplevel, title);
}