#define _POSIX_C_SOURCE 200809L
#include <assert.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdlib.h>
#include <unistd.h>
#include <wlr/render/interface.h>
#include <wlr/render/pixman.h>
#include <wlr/render/wlr_renderer.h>
#include <wlr/types/wlr_drm.h>
#include <wlr/types/wlr_linux_dmabuf_v1.h>
#include <wlr/types/wlr_shm.h>
#include <wlr/util/box.h>
#include <wlr/util/log.h>
#include <xf86drm.h>

#include <wlr/config.h>

#if WLR_HAS_GLES2_RENDERER
#include <wlr/render/egl.h>
#include <wlr/render/gles2.h>
#endif

#if WLR_HAS_VULKAN_RENDERER
#include <wlr/render/vulkan.h>
#endif // WLR_HAS_VULKAN_RENDERER

#include "backend/backend.h"
#include "render/pixel_format.h"
#include "render/wlr_renderer.h"
#include "util/env.h"

void wlr_renderer_init(struct wlr_renderer *renderer,
		const struct wlr_renderer_impl *impl) {
	assert(impl->begin_buffer_pass);
	assert(impl->get_shm_texture_formats);
	assert(impl->get_render_buffer_caps);

	*renderer = (struct wlr_renderer){
		.impl = impl,
	};

	wl_signal_init(&renderer->events.destroy);
	wl_signal_init(&renderer->events.lost);
}

void wlr_renderer_destroy(struct wlr_renderer *r) {
	if (!r) {
		return;
	}

	assert(!r->rendering);

	wl_signal_emit_mutable(&r->events.destroy, r);

	if (r->impl && r->impl->destroy) {
		r->impl->destroy(r);
	} else {
		free(r);
	}
}

bool renderer_bind_buffer(struct wlr_renderer *r, struct wlr_buffer *buffer) {
	assert(!r->rendering);
	if (!r->impl->bind_buffer) {
		return false;
	}
	return r->impl->bind_buffer(r, buffer);
}

bool wlr_renderer_begin_with_buffer(struct wlr_renderer *r,
		struct wlr_buffer *buffer) {
	assert(!r->rendering);

	if (!renderer_bind_buffer(r, buffer)) {
		return false;
	}
	if (!r->impl->begin(r, buffer->width, buffer->height)) {
		renderer_bind_buffer(r, NULL);
		return false;
	}

	r->rendering = true;
	return true;
}

void wlr_renderer_end(struct wlr_renderer *r) {
	assert(r->rendering);

	if (r->impl->end) {
		r->impl->end(r);
	}

	r->rendering = false;
	renderer_bind_buffer(r, NULL);
}

const uint32_t *wlr_renderer_get_shm_texture_formats(struct wlr_renderer *r,
		size_t *len) {
	return r->impl->get_shm_texture_formats(r, len);
}

const struct wlr_drm_format_set *wlr_renderer_get_dmabuf_texture_formats(
		struct wlr_renderer *r) {
	if (!r->impl->get_dmabuf_texture_formats) {
		return NULL;
	}
	return r->impl->get_dmabuf_texture_formats(r);
}

const struct wlr_drm_format_set *wlr_renderer_get_render_formats(
		struct wlr_renderer *r) {
	if (!r->impl->get_render_formats) {
		return NULL;
	}
	return r->impl->get_render_formats(r);
}

uint32_t renderer_get_render_buffer_caps(struct wlr_renderer *r) {
	return r->impl->get_render_buffer_caps(r);
}

bool wlr_renderer_init_wl_shm(struct wlr_renderer *r,
		struct wl_display *wl_display) {
	return wlr_shm_create_with_renderer(wl_display, 1, r) != NULL;
}

bool wlr_renderer_init_wl_display(struct wlr_renderer *r,
		struct wl_display *wl_display) {
	if (!wlr_renderer_init_wl_shm(r, wl_display)) {
		return false;
	}

	if (wlr_renderer_get_dmabuf_texture_formats(r) != NULL) {
		if (wlr_renderer_get_drm_fd(r) >= 0) {
			if (wlr_drm_create(wl_display, r) == NULL) {
				return false;
			}
		} else {
			wlr_log(WLR_INFO, "Cannot get renderer DRM FD, disabling wl_drm");
		}

		if (wlr_linux_dmabuf_v1_create_with_renderer(wl_display, 4, r) == NULL) {
			return false;
		}
	}

	return true;
}

static int open_drm_render_node(void) {
	uint32_t flags = 0;
	int devices_len = drmGetDevices2(flags, NULL, 0);
	if (devices_len < 0) {
		wlr_log(WLR_ERROR, "drmGetDevices2 failed: %s", strerror(-devices_len));
		return -1;
	}
	drmDevice **devices = calloc(devices_len, sizeof(*devices));
	if (devices == NULL) {
		wlr_log_errno(WLR_ERROR, "Allocation failed");
		return -1;
	}
	devices_len = drmGetDevices2(flags, devices, devices_len);
	if (devices_len < 0) {
		free(devices);
		wlr_log(WLR_ERROR, "drmGetDevices2 failed: %s", strerror(-devices_len));
		return -1;
	}

	int fd = -1;
	for (int i = 0; i < devices_len; i++) {
		drmDevice *dev = devices[i];
		if (dev->available_nodes & (1 << DRM_NODE_RENDER)) {
			const char *name = dev->nodes[DRM_NODE_RENDER];
			wlr_log(WLR_DEBUG, "Opening DRM render node '%s'", name);
			fd = open(name, O_RDWR | O_CLOEXEC);
			if (fd < 0) {
				wlr_log_errno(WLR_ERROR, "Failed to open '%s'", name);
				goto out;
			}
			break;
		}
	}
	if (fd < 0) {
		wlr_log(WLR_ERROR, "Failed to find any DRM render node");
	}

out:
	for (int i = 0; i < devices_len; i++) {
		drmFreeDevice(&devices[i]);
	}
	free(devices);

	return fd;
}

static bool open_preferred_drm_fd(struct wlr_backend *backend, int *drm_fd_ptr,
		bool *own_drm_fd) {
	if (*drm_fd_ptr >= 0) {
		return true;
	}

	// Allow the user to override the render node
	const char *render_name = getenv("WLR_RENDER_DRM_DEVICE");
	if (render_name != NULL) {
		wlr_log(WLR_INFO,
			"Opening DRM render node '%s' from WLR_RENDER_DRM_DEVICE",
			render_name);
		int drm_fd = open(render_name, O_RDWR | O_CLOEXEC);
		if (drm_fd < 0) {
			wlr_log_errno(WLR_ERROR, "Failed to open '%s'", render_name);
			return false;
		}
		if (drmGetNodeTypeFromFd(drm_fd) != DRM_NODE_RENDER) {
			wlr_log(WLR_ERROR, "'%s' is not a DRM render node", render_name);
			close(drm_fd);
			return false;
		}
		*drm_fd_ptr = drm_fd;
		*own_drm_fd = true;
		return true;
	}

	// Prefer the backend's DRM node, if any
	int backend_drm_fd = wlr_backend_get_drm_fd(backend);
	if (backend_drm_fd >= 0) {
		*drm_fd_ptr = backend_drm_fd;
		*own_drm_fd = false;
		return true;
	}

	// If the backend hasn't picked a DRM FD, but accepts DMA-BUFs, pick an
	// arbitrary render node
	uint32_t backend_caps = backend_get_buffer_caps(backend);
	if (backend_caps & WLR_BUFFER_CAP_DMABUF) {
		int drm_fd = open_drm_render_node();
		if (drm_fd < 0) {
			return false;
		}
		*drm_fd_ptr = drm_fd;
		*own_drm_fd = true;
		return true;
	}

	return false;
}

static void log_creation_failure(bool is_auto, const char *msg) {
	wlr_log(is_auto ? WLR_DEBUG : WLR_ERROR, "%s%s", msg, is_auto ? ". Skipping!" : "");
}

static bool has_render_node(struct wlr_backend *backend) {
	if (!backend) {
		return false;
	}

	int backend_drm_fd = wlr_backend_get_drm_fd(backend);
	if (backend_drm_fd < 0) {
		return false;
	}

	char *render_node = drmGetRenderDeviceNameFromFd(backend_drm_fd);
	bool has_render_node = render_node != NULL;
	free(render_node);

	return has_render_node;
}

static struct wlr_renderer *renderer_autocreate(struct wlr_backend *backend, int drm_fd) {
	const char *renderer_options[] = {
		"auto",
		"gles2",
		"vulkan",
		"pixman",
		NULL
	};

	const char *renderer_name = renderer_options[env_parse_switch("WLR_RENDERER", renderer_options)];
	bool is_auto = strcmp(renderer_name, "auto") == 0;
	struct wlr_renderer *renderer = NULL;

	bool own_drm_fd = false;

	if ((is_auto && WLR_HAS_GLES2_RENDERER) || strcmp(renderer_name, "gles2") == 0) {
		if (!open_preferred_drm_fd(backend, &drm_fd, &own_drm_fd)) {
			log_creation_failure(is_auto, "Cannot create GLES2 renderer: no DRM FD available");
		} else {
#if WLR_HAS_GLES2_RENDERER
			renderer = wlr_gles2_renderer_create_with_drm_fd(drm_fd);
#else
			wlr_log(WLR_ERROR, "Cannot create GLES renderer: disabled at compile-time");
#endif
			if (renderer) {
				goto out;
			} else {
				log_creation_failure(is_auto, "Failed to create a GLES2 renderer");
			}
		}
	}

	if (strcmp(renderer_name, "vulkan") == 0) {
		if (!open_preferred_drm_fd(backend, &drm_fd, &own_drm_fd)) {
			log_creation_failure(is_auto, "Cannot create Vulkan renderer: no DRM FD available");
		} else {
#if WLR_HAS_VULKAN_RENDERER
			renderer = wlr_vk_renderer_create_with_drm_fd(drm_fd);
#else
			wlr_log(WLR_ERROR, "Cannot create Vulkan renderer: disabled at compile-time");
#endif
			if (renderer) {
				goto out;
			} else {
				log_creation_failure(is_auto, "Failed to create a Vulkan renderer");
			}
		}
	}

	if ((is_auto && !has_render_node(backend)) || strcmp(renderer_name, "pixman") == 0) {
		renderer = wlr_pixman_renderer_create();
		if (renderer) {
			goto out;
		} else {
			log_creation_failure(is_auto, "Failed to create a pixman renderer");
		}
	}

out:
	if (renderer == NULL) {
		wlr_log(WLR_ERROR, "Could not initialize renderer");
	}
	if (own_drm_fd && drm_fd >= 0) {
		close(drm_fd);
	}
	return renderer;
}

struct wlr_renderer *renderer_autocreate_with_drm_fd(int drm_fd) {
	assert(drm_fd >= 0);

	return renderer_autocreate(NULL, drm_fd);
}

struct wlr_renderer *wlr_renderer_autocreate(struct wlr_backend *backend) {
	return renderer_autocreate(backend, -1);
}

int wlr_renderer_get_drm_fd(struct wlr_renderer *r) {
	if (!r->impl->get_drm_fd) {
		return -1;
	}
	return r->impl->get_drm_fd(r);
}

struct wlr_render_pass *wlr_renderer_begin_buffer_pass(struct wlr_renderer *renderer,
		struct wlr_buffer *buffer, const struct wlr_buffer_pass_options *options) {
	struct wlr_buffer_pass_options default_options = {0};
	if (!options) {
		options = &default_options;
	}

	return renderer->impl->begin_buffer_pass(renderer, buffer, options);
}

struct wlr_render_timer *wlr_render_timer_create(struct wlr_renderer *renderer) {
	if (!renderer->impl->render_timer_create) {
		return NULL;
	}
	return renderer->impl->render_timer_create(renderer);
}

int wlr_render_timer_get_duration_ns(struct wlr_render_timer *timer) {
	if (!timer->impl->get_duration_ns) {
		return -1;
	}
	return timer->impl->get_duration_ns(timer);
}

void wlr_render_timer_destroy(struct wlr_render_timer *timer) {
	if (!timer->impl->destroy) {
		return;
	}
	timer->impl->destroy(timer);
}