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

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <wayland-client-protocol.h>

#include "graphics.h"
#include "ufkbd.h"
#include "layout.h"
#include "wayland.h"
#include "wayland/viewporter.h"
#include "wayland/wlr-layer-shell-unstable-v1.h"

extern struct ufkbd_driver ufkbd_wayland;

static int ufkbd_wl_surface_resize_buffers(struct ufkbd_wl_surface *ctx,
					   uint32_t width, uint32_t height);

static void on_surface_configure(void *data,
				 struct zwlr_layer_surface_v1 *surface,
				 uint32_t serial,
				 uint32_t width,
				 uint32_t height)
{
	struct ufkbd_wl_surface *ctx = data;
	struct ufkbd_input_wayland *ufkbd_wl = ctx->ufkbd_wl;
	struct ufkbd_ctx *ufkbd = ufkbd_wl->ufkbd;

	zwlr_layer_surface_v1_ack_configure(surface, serial);

	wp_viewport_set_source(ctx->vp, 0, 0, width * 256 * ctx->scale,
			       height * 256 * ctx->scale);
	wp_viewport_set_destination(ctx->vp, width, height);

	ufkbd_wl_surface_resize_buffers(ctx, width, height);

	ufkbd_layout_resize(ufkbd->layout, width, height);
	ufkbd_graphics_draw_layout(ufkbd, ufkbd_wl->ufkbd->layout,
				   width, height);
}

static void on_surface_closed(void *data,
			      struct zwlr_layer_surface_v1 *toplev)
{
	struct ufkbd_wl_surface *ctx = data;
	struct ufkbd_input_wayland *ufkbd_wl = ctx->ufkbd_wl;
	struct ufkbd_ctx *ufkbd = ufkbd_wl->ufkbd;

	ufkbd_terminate(ufkbd);
}

static const struct zwlr_layer_surface_v1_listener surface_listener = {
	.configure = on_surface_configure,
	.closed = on_surface_closed,
};

static int try_create_layer_surface(struct ufkbd_wl_surface *ctx)
{
	if (ctx->wl == NULL)
		return -EINVAL;

	if (ctx->shell == NULL)
		return -EINVAL;

	if (ctx->vper == NULL)
		return -EINVAL;

	ctx->vp = wp_viewporter_get_viewport(ctx->vper, ctx->wl);
	if (ctx->vp == NULL)
		return -ENOMEM;

	ctx->wlr = zwlr_layer_shell_v1_get_layer_surface(ctx->shell, ctx->wl, NULL, ZWLR_LAYER_SHELL_V1_LAYER_TOP, "ufkbd-osk");
	if (ctx->wlr == NULL)
		return -ENOMEM;

	zwlr_layer_surface_v1_set_anchor(ctx->wlr,
					 ZWLR_LAYER_SURFACE_V1_ANCHOR_LEFT
				       | ZWLR_LAYER_SURFACE_V1_ANCHOR_RIGHT
				       | ZWLR_LAYER_SURFACE_V1_ANCHOR_BOTTOM);
	zwlr_layer_surface_v1_set_size(ctx->wlr, 0, 185);
	zwlr_layer_surface_v1_set_exclusive_zone(ctx->wlr, 185);

	zwlr_layer_surface_v1_add_listener(ctx->wlr, &surface_listener, ctx);

	// Commit the role given to the surface
	wl_surface_commit(ctx->wl);

	return 0;
}

static void on_global_compositor(void *data,
				 struct wl_registry *reg,
				 uint32_t name,
				 uint32_t version)
{
	struct ufkbd_wl_surface *ctx = data;

	if (version < WL_COMPOSITOR_CREATE_SURFACE_SINCE_VERSION)
		return;

	ctx->compositor = wl_registry_bind(reg,
					   name,
					   &wl_compositor_interface,
					   version);
	if (ctx->compositor == NULL) {
		fprintf(stderr, "warn: could not bind to compositor\n");
		return;
	}

	ctx->wl = wl_compositor_create_surface(ctx->compositor);
	if (ctx->wl == NULL) {
		fprintf(stderr, "warn: no valid surface\n");
		return;
	}

	try_create_layer_surface(ctx);
}

static void on_global_shell(void *data,
			    struct wl_registry *reg,
			    uint32_t name,
			    uint32_t version)
{
	struct ufkbd_wl_surface *ctx = data;

	ctx->shell = wl_registry_bind(reg,
				      name,
				      &zwlr_layer_shell_v1_interface,
				      version);
	if (ctx->shell == NULL) {
		fprintf(stderr, "wl: warn: could not bind to window manager\n");
		return;
	}

	try_create_layer_surface(ctx);
}

static void on_global_viewporter(void *data,
				 struct wl_registry *reg,
				 uint32_t name,
				 uint32_t version)
{
	struct ufkbd_wl_surface *ctx = data;

	ctx->vper = wl_registry_bind(reg,
				     name,
				     &wp_viewporter_interface,
				     version);
	if (ctx->vper == NULL) {
		fprintf(stderr, "wl: warn: could not bind to viewporter\n");
		return;
	}

	try_create_layer_surface(ctx);
}

int ufkbd_wl_surface_consume_buffer(struct ufkbd_wl_surface *ctx,
				    struct wl_buffer **buf, void **ptr)
{
	int ret, i;

	if (buf == NULL || ptr == NULL)
		return -EINVAL;

	for (i = 0; i < 2; i++) {
		ret = ufkbd_wl_buffer_consume(&ctx->bufs[i], buf, ptr);
		if (!ret) {
			wl_surface_attach(ctx->wl, *buf, 0, 0);
			ctx->used_buf = i;
			break;
		}

		if (ret != -EBUSY)
			break;
	}

	return ret;
}

static int ufkbd_wl_surface_resize_buffers(struct ufkbd_wl_surface *ctx,
					   uint32_t width, uint32_t height)
{
	int ret;

	ctx->stride = (size_t) width * 4;

	ret = ufkbd_wl_buffer_resize(&ctx->bufs[0],
				     width * ctx->scale,
				     height * ctx->scale);
	if (ret)
		return ret;

	return ufkbd_wl_buffer_resize(&ctx->bufs[1],
				      width * ctx->scale,
				      height * ctx->scale);
}

void ufkbd_wl_surface_release_unused(struct ufkbd_wl_surface *ctx)
{
	int i;

	for (i = 0; i < 2; i++) {
		if (i != ctx->used_buf)
			ufkbd_wl_buffer_release(&ctx->bufs[i]);
	}
}

int ufkbd_wl_surface_init(struct ufkbd_input_wayland *ufkbd_wl,
			  struct ufkbd_wl_surface **out)
{
	struct ufkbd_wl_surface *ctx;
	int ret;

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

	ctx->ufkbd_wl = ufkbd_wl;
	ctx->scale = 1;
	ctx->used_buf = -1;

	ret = ufkbd_wl_buffer_init(&ctx->bufs[0], ufkbd_wl, 0);
	if (ret)
		goto err_free_ctx;

	ret = ufkbd_wl_buffer_init(&ctx->bufs[1], ufkbd_wl, 1);
	if (ret)
		goto err_uninit_buf0;

	ctx->listener_comp.iface = &wl_compositor_interface;
	ctx->listener_comp.cb = on_global_compositor;
	ctx->listener_comp.data = ctx;

	ret = ufkbd_wl_global_listener_add(ufkbd_wl, &ctx->listener_comp);
	if (ret)
		goto err_uninit_buf1;

	ctx->listener_shell.iface = &zwlr_layer_shell_v1_interface;
	ctx->listener_shell.cb = on_global_shell;
	ctx->listener_shell.data = ctx;

	ret = ufkbd_wl_global_listener_add(ufkbd_wl, &ctx->listener_shell);
	if (ret)
		goto err_uninit_buf1;

	ctx->listener_viewporter.iface = &wp_viewporter_interface;
	ctx->listener_viewporter.cb = on_global_viewporter;
	ctx->listener_viewporter.data = ctx;

	ret = ufkbd_wl_global_listener_add(ufkbd_wl, &ctx->listener_viewporter);
	if (ret)
		goto err_uninit_buf1;

	ufkbd_graphics_set_scale(ctx->ufkbd_wl->ufkbd->graphics, ctx->scale);

	*out = ctx;

	return 0;

err_uninit_buf1:
	ufkbd_wl_buffer_uninit(&ctx->bufs[1]);
err_uninit_buf0:
	ufkbd_wl_buffer_uninit(&ctx->bufs[0]);
err_free_ctx:
	free(ctx);
	return ret;
}

void ufkbd_wl_surface_uninit(struct ufkbd_wl_surface *ctx)
{
	if (ctx->vper != NULL)
		wp_viewporter_destroy(ctx->vper);

	if (ctx->vp != NULL)
		wp_viewport_destroy(ctx->vp);

	if (ctx->wlr != NULL)
		zwlr_layer_surface_v1_destroy(ctx->wlr);

	if (ctx->wl != NULL)
		wl_surface_destroy(ctx->wl);

	if (ctx->shell != NULL)
		zwlr_layer_shell_v1_destroy(ctx->shell);

	if (ctx->compositor != NULL)
		wl_compositor_destroy(ctx->compositor);

	ufkbd_wl_buffer_uninit(&ctx->bufs[1]);
	ufkbd_wl_buffer_uninit(&ctx->bufs[0]);

	free(ctx);
}