// SPDX-License-Identifier: GPL-3.0-only
/*
 * Wayland driver.
 *
 * Copyright (c) 2024, Richard Acayan. All rights reserved.
 */

#include <errno.h>
#include <poll.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <wayland-client.h>
#include <xkbcommon/xkbcommon.h>

#include "input.h"
#include "ufkbd.h"
#include "wayland.h"

static void on_global_object(void *data,
			     struct wl_registry *reg,
			     uint32_t name,
			     const char *iface,
			     uint32_t version);

static const struct wl_registry_listener reg_listener = {
	.global = on_global_object,
	.global_remove = NULL,
};

static void on_global_object(void *data,
			     struct wl_registry *reg,
			     uint32_t name,
			     const char *iface,
			     uint32_t version)
{
	struct ufkbd_input_wayland *ctx = data;
	struct ufkbd_wl_global_listener *listener;
	size_t i;

	// This is assumed to be a small list.
	for (i = 0; i < ctx->n_global_listeners; i++) {
		listener = ctx->global_listeners[i];

		if (!strcmp(iface, listener->iface->name))
			listener->cb(listener->data, reg, name, version);
	}
}

int ufkbd_wl_global_listener_add(struct ufkbd_input_wayland *ctx,
				 struct ufkbd_wl_global_listener *listener)
{
	size_t idx = ctx->n_global_listeners;

	if (idx >= MAX_GLOBAL_LISTENERS) {
		fprintf(stderr, "wl: no space for internal callback\n");
		return -ENOSPC;
	}

	ctx->global_listeners[idx] = listener;
	ctx->n_global_listeners++;

	return 0;
}

static void ufkbd_wayland_listen_one(void *data, bool block)
{
	struct ufkbd_input_wayland *ctx = data;
	struct pollfd pollfd;
	int timeout = 0;
	int ret;

	if (block)
		timeout = -1;

	// Some listen events may be queued, so send them.
	ret = wl_display_flush(ctx->display);
	if (ret < 0)
		fprintf(stderr, "warn: failed to flush outgoing events: %d\n", -errno);

	pollfd.fd = ctx->fd;
	pollfd.events = POLLIN;
	pollfd.revents = 0;

	ret = poll(&pollfd, 1, timeout);
	if (ret == -1)
		return;

	if (pollfd.revents) {
		ret = wl_display_dispatch(ctx->display);
		if (ret == -1)
			return;
	}
}

static void ufkbd_wayland_listen_step(void *data, int timeout)
{
	struct ufkbd_input_wayland *ctx = data;
	struct pollfd pollfd;
	int ret;

	// Some listen events may be queued, so send them.
	ret = wl_display_flush(ctx->display);
	if (ret < 0)
		fprintf(stderr, "warn: failed to flush outgoing events: %d\n", -errno);

	pollfd.fd = ctx->fd;
	pollfd.events = POLLIN;
	pollfd.revents = 0;

	ret = poll(&pollfd, 1, timeout);
	if (ret == -1)
		return;

	if (pollfd.revents) {
		ret = wl_display_dispatch(ctx->display);
		if (ret == -1)
			return;
	}
}

static int ufkbd_wayland_send_key(void *data, int code, bool repeat)
{
	struct ufkbd_input_wayland *ctx = data;

	ufkbd_wl_input_send_key(ctx->input, code - 8, repeat);

	return 0;
}

static int ufkbd_wayland_send_mod(void *data, enum ufkbd_modifier mod, bool pressed)
{
	struct ufkbd_input_wayland *ctx = data;

	ufkbd_wl_input_send_mod(ctx->input, mod, pressed);

	return 0;
}

static int ufkbd_wayland_draw_begin(void *data, size_t *stride, void **ptr)
{
	struct ufkbd_input_wayland *ctx = data;
	struct wl_buffer *buf;
	int ret;

	ret = ufkbd_wl_surface_consume_buffer(ctx->surface, &buf, ptr);
	if (ret) {
		fprintf(stderr, "wl: warn: could not consume buffer: %s\n",
			strerror(-ret));
		return ret;
	}

	// NOPUSH
	*stride = (size_t) ctx->surface->bufs[0].width * 4;

	return 0;
}

static void ufkbd_wayland_draw_touch(void *data, int x, int y, int width, int height)
{
	struct ufkbd_input_wayland *ctx = data;

	wl_surface_damage_buffer(ctx->surface->wl, x, y, width, height);
}

static void ufkbd_wayland_draw_end(void *data)
{
	struct ufkbd_input_wayland *ctx = data;

	wl_surface_commit(ctx->surface->wl);
	ufkbd_wl_surface_release_unused(ctx->surface);
}

static void *ufkbd_wayland_init(struct ufkbd_ctx *ufkbd)
{
	struct ufkbd_input_wayland *ctx;
	int ret;

	if (ufkbd == NULL)
		return NULL;

	ctx = calloc(1, sizeof(*ctx));
	if (ctx == NULL)
		return NULL;

	ctx->ufkbd = ufkbd;

	ctx->display = wl_display_connect(NULL);
	if (ctx->display == NULL)
		goto err_free_ctx;

	ctx->registry = wl_display_get_registry(ctx->display);
	if (ctx->registry == NULL)
		goto err_disconnect;

	ret = wl_registry_add_listener(ctx->registry, &reg_listener, ctx);
	if (ret)
		goto err_destroy_reg;

	ret = ufkbd_wl_surface_init(ctx, &ctx->surface);
	if (ret)
		goto err_destroy_reg;

	ret = ufkbd_wl_input_init(ctx, &ctx->input);
	if (ret)
		goto err_uninit_surface;

	ctx->fd = wl_display_get_fd(ctx->display);

	return ctx;

err_uninit_surface:
	ufkbd_wl_surface_uninit(ctx->surface);
err_destroy_reg:
	wl_registry_destroy(ctx->registry);
err_disconnect:
	wl_display_disconnect(ctx->display);
err_free_ctx:
	free(ctx);
	return NULL;
}

static void ufkbd_wayland_uninit(void *data)
{
	struct ufkbd_input_wayland *ctx = data;

	ufkbd_wl_input_uninit(ctx->input);
	ufkbd_wl_surface_uninit(ctx->surface);

	wl_registry_destroy(ctx->registry);
	wl_display_disconnect(ctx->display);

	free(ctx);
}

struct ufkbd_driver ufkbd_wayland = {
	.init = ufkbd_wayland_init,
	.uninit = ufkbd_wayland_uninit,
	.listen_one = ufkbd_wayland_listen_one,
	.listen_step = ufkbd_wayland_listen_step,
	.send_key = ufkbd_wayland_send_key,
	.send_mod = ufkbd_wayland_send_mod,
	.draw_begin = ufkbd_wayland_draw_begin,
	.draw_touch = ufkbd_wayland_draw_touch,
	.draw_end = ufkbd_wayland_draw_end,
};