/*
	render.c

	Vulkan render manager

	Copyright (C) 2023      Bill Currie <bill@taniwha.org>

	This program is free software; you can redistribute it and/or
	modify it under the terms of the GNU General Public License
	as published by the Free Software Foundation; either version 2
	of the License, or (at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

	See the GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to:

		Free Software Foundation, Inc.
		59 Temple Place - Suite 330
		Boston, MA  02111-1307, USA

*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#ifdef HAVE_MATH_H
# include <math.h>
#endif
#ifdef HAVE_STRING_H
# include <string.h>
#endif
#ifdef HAVE_STRINGS_H
# include <strings.h>
#endif

#include "QF/cmem.h"
#include "QF/hash.h"
#include "QF/va.h"
#include "QF/Vulkan/command.h"
#include "QF/Vulkan/debug.h"
#include "QF/Vulkan/device.h"
#include "QF/Vulkan/image.h"
#include "QF/Vulkan/pipeline.h"
#include "QF/Vulkan/render.h"
#include "QF/Vulkan/resource.h"
#include "QF/Vulkan/swapchain.h"
#include "vid_vulkan.h"

#include "vkparse.h"

VkCommandBuffer
QFV_GetCmdBufffer (vulkan_ctx_t *ctx, bool secondary)
{
	qfv_device_t *device = ctx->device;
	qfv_devfuncs_t *dfunc = device->funcs;
	__auto_type rctx = ctx->render_context;
	__auto_type job = rctx->job;

	VkCommandBufferAllocateInfo cinfo = {
		.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO,
		.commandPool = job->command_pool,
		.level = secondary ? VK_COMMAND_BUFFER_LEVEL_SECONDARY
						   : VK_COMMAND_BUFFER_LEVEL_PRIMARY,
		.commandBufferCount = 1,
	};
	VkCommandBuffer cmd;
	dfunc->vkAllocateCommandBuffers (device->dev, &cinfo, &cmd);
	return cmd;
}

void
QFV_AppendCmdBuffer (vulkan_ctx_t *ctx, VkCommandBuffer cmd)
{
	__auto_type rctx = ctx->render_context;
	__auto_type job = rctx->job;
	DARRAY_APPEND (&job->commands, cmd);
}

static void
run_tasks (uint32_t task_count, qfv_taskinfo_t *tasks, qfv_taskctx_t *ctx)
{
	for (uint32_t i = 0; i < task_count; i++) {
		tasks[i].func->func (tasks[i].params, 0, (exprctx_t *) ctx);
	}
}

static void
run_pipeline (qfv_pipeline_t *pipeline, VkCommandBuffer cmd, vulkan_ctx_t *ctx)
{
	qfv_device_t *device = ctx->device;
	qfv_devfuncs_t *dfunc = device->funcs;
	dfunc->vkCmdBindPipeline (cmd, pipeline->bindPoint, pipeline->pipeline);
	dfunc->vkCmdSetViewport (cmd, 0, 1, &pipeline->viewport);
	dfunc->vkCmdSetScissor (cmd, 0, 1, &pipeline->scissor);

	qfv_taskctx_t taskctx = {
		.ctx = ctx,
		.pipeline = pipeline,
		.cmd = cmd,
	};
	run_tasks (pipeline->task_count, pipeline->tasks, &taskctx);

	if (pipeline->num_descriptorsets) {
		dfunc->vkCmdBindDescriptorSets (cmd, pipeline->bindPoint,
										pipeline->layout,
										pipeline->first_descriptorset,
										pipeline->num_descriptorsets,
										pipeline->descriptorsets,
										0, 0);
	}
}

// https://themaister.net/blog/2019/08/14/yet-another-blog-explaining-vulkan-synchronization/
static void
run_subpass (qfv_subpass_t *sp, VkCommandBuffer cmd, vulkan_ctx_t *ctx)
{
	qfv_device_t *device = ctx->device;
	qfv_devfuncs_t *dfunc = device->funcs;
	dfunc->vkBeginCommandBuffer (cmd, &sp->beginInfo);
	QFV_duCmdBeginLabel (device, cmd, sp->label.name,
						 {VEC4_EXP (sp->label.color)});

	for (uint32_t i = 0; i < sp->pipeline_count; i++) {
		__auto_type pipeline = &sp->pipelines[i];
		run_pipeline (pipeline, cmd, ctx);
	}

	QFV_duCmdEndLabel (device, cmd);
	dfunc->vkEndCommandBuffer (cmd);
}

static void
run_renderpass (qfv_renderpass_t *rp, vulkan_ctx_t *ctx)
{
	printf ("%10.2f run_renderpass: %s\n", Sys_DoubleTime (), rp->label.name);

	qfv_device_t *device = ctx->device;
	qfv_devfuncs_t *dfunc = device->funcs;
	__auto_type rctx = ctx->render_context;
	__auto_type job = rctx->job;

	VkCommandBuffer cmd = QFV_GetCmdBufffer (ctx, false);
	VkCommandBufferBeginInfo beginInfo = {
		VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO,
	};
	dfunc->vkBeginCommandBuffer (cmd, &beginInfo);
	QFV_duCmdBeginLabel (device, cmd, rp->label.name,
						 {VEC4_EXP (rp->label.color)});
	dfunc->vkCmdBeginRenderPass (cmd, &rp->beginInfo, rp->subpassContents);
	for (uint32_t i = 0; i < rp->subpass_count; i++) {
		__auto_type sp = &rp->subpasses[i];
		VkCommandBuffer subcmd = QFV_GetCmdBufffer (ctx, true);
		run_subpass (sp, subcmd, ctx);
		dfunc->vkCmdExecuteCommands (cmd, 1, &subcmd);
		//FIXME comment is a bit off as exactly one buffer is always submitted
		//
		//Regardless of whether any commands were submitted for this
		//subpass, must step through each and every subpass, otherwise
		//the attachments won't be transitioned correctly.
		//However, only if not the last (or only) subpass.
		if (i < rp->subpass_count - 1) {
			dfunc->vkCmdNextSubpass (cmd, rp->subpassContents);
		}
	}
	dfunc->vkCmdEndRenderPass (cmd);
	QFV_CmdEndLabel (device, cmd);
	dfunc->vkEndCommandBuffer (cmd);
	DARRAY_APPEND (&job->commands, cmd);
}

static void
run_compute_pipeline (qfv_pipeline_t *pipeline, VkCommandBuffer cmd,
					  vulkan_ctx_t *ctx)
{
	printf ("run_compute_pipeline: %s\n", pipeline->label.name);

	qfv_device_t *device = ctx->device;
	qfv_devfuncs_t *dfunc = device->funcs;
	dfunc->vkCmdBindPipeline (cmd, pipeline->bindPoint, pipeline->pipeline);

	qfv_taskctx_t taskctx = {
		.ctx = ctx,
		.pipeline = pipeline,
		.cmd = cmd,
	};
	run_tasks (pipeline->task_count, pipeline->tasks, &taskctx);

	if (pipeline->num_descriptorsets) {
		dfunc->vkCmdBindDescriptorSets (cmd, pipeline->bindPoint,
										pipeline->layout,
										pipeline->first_descriptorset,
										pipeline->num_descriptorsets,
										pipeline->descriptorsets,
										0, 0);
	}
	vec4u_t     d = pipeline->dispatch;
	dfunc->vkCmdDispatch (cmd, d[0], d[1], d[2]);
}

static void
run_compute (qfv_compute_t *comp, vulkan_ctx_t *ctx)
{
	qfv_device_t *device = ctx->device;
	qfv_devfuncs_t *dfunc = device->funcs;
	__auto_type rctx = ctx->render_context;
	__auto_type job = rctx->job;

	VkCommandBuffer cmd = QFV_GetCmdBufffer (ctx, false);

	VkCommandBufferBeginInfo beginInfo = {
		.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO,
		.flags = VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT,
	};
	dfunc->vkBeginCommandBuffer (cmd, &beginInfo);
	for (uint32_t i = 0; i < comp->pipeline_count; i++) {
		__auto_type pipeline = &comp->pipelines[i];
		run_compute_pipeline (pipeline, cmd, ctx);
	}
	dfunc->vkEndCommandBuffer (cmd);
	DARRAY_APPEND (&job->commands, cmd);
}

static void
run_process (qfv_process_t *proc, vulkan_ctx_t *ctx)
{
	qfv_taskctx_t taskctx = {
		.ctx = ctx,
	};
	run_tasks (proc->task_count, proc->tasks, &taskctx);
}

void
QFV_RunRenderJob (vulkan_ctx_t *ctx)
{
	auto rctx = ctx->render_context;
	auto job = rctx->job;

	for (uint32_t i = 0; i < job->num_steps; i++) {
		__auto_type step = &job->steps[i];
		printf ("%10.2f run_step: %s\n", Sys_DoubleTime (), step->label.name);
		if (step->render) {
			run_renderpass (step->render->active, ctx);
		}
		if (step->compute) {
			run_compute (step->compute, ctx);
		}
		if (step->process) {
			run_process (step->process, ctx);
		}
	}

	auto device = ctx->device;
	auto dfunc = device->funcs;
	auto queue = &device->queue;
	auto frame = &ctx->frames.a[ctx->curFrame];
	VkPipelineStageFlags waitStage
		= VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
	VkSubmitInfo submitInfo = {
		VK_STRUCTURE_TYPE_SUBMIT_INFO, 0,
		1, &frame->imageAvailableSemaphore, &waitStage,
		job->commands.size, job->commands.a,
		1, &frame->renderDoneSemaphore,
	};
	printf ("%10.2f submit for frame %d: %zd %p\n", Sys_DoubleTime (),
			ctx->curFrame, job->commands.size, frame->imageAvailableSemaphore);
	dfunc->vkResetFences (device->dev, 1, &frame->fence);
	dfunc->vkQueueSubmit (queue->queue, 1, &submitInfo, frame->fence);

	VkPresentInfoKHR presentInfo = {
		VK_STRUCTURE_TYPE_PRESENT_INFO_KHR, 0,
		1, &frame->renderDoneSemaphore,
		1, &ctx->swapchain->swapchain, &ctx->swapImageIndex,
		0
	};
	dfunc->vkQueuePresentKHR (queue->queue, &presentInfo);
}

#if 0
void
QFV_DestroyFramebuffer (vulkan_ctx_t *ctx)
{
	qfv_device_t *device = ctx->device;
	qfv_devfuncs_t *dfunc = device->funcs;
	__auto_type rctx = ctx->render_context;
	__auto_type job = rctx->job;
	__auto_type rp = &job->renderpasses[0];

	if (rp->beginInfo.framebuffer) {
		VkFramebuffer framebuffer = rp->beginInfo.framebuffer;
		rp->beginInfo.framebuffer = 0;
		dfunc->vkDestroyFramebuffer (device->dev, framebuffer, 0);
	}
}
#endif

static VkImageView __attribute__((pure))
find_imageview (qfv_reference_t *ref, qfv_renderctx_t *rctx)
{
	__auto_type jinfo = rctx->jobinfo;
	__auto_type job = rctx->job;
	const char *name = ref->name;

	if (strncmp (name, "$imageviews.", 7) == 0) {
		name += 7;
	}

	for (uint32_t i = 0; i < jinfo->num_imageviews; i++) {
		__auto_type vi = &jinfo->imageviews[i];
		__auto_type vo = &job->image_views[i];
		if (strcmp (name, vi->name) == 0) {
			return vo->image_view.view;
		}
	}
	Sys_Error ("%d:invalid imageview: %s", ref->line, ref->name);
}

void
QFV_CreateFramebuffer (vulkan_ctx_t *ctx, qfv_renderpass_t *rp)
{
	__auto_type rctx = ctx->render_context;

	auto fb = rp->framebufferinfo;
	VkImageView attachments[fb->num_attachments];
	VkFramebufferCreateInfo cInfo = {
		.sType = VK_STRUCTURE_TYPE_FRAMEBUFFER_CREATE_INFO,
		.attachmentCount = fb->num_attachments,
		.pAttachments = attachments,
		.renderPass = rp->beginInfo.renderPass,
		.width = fb->width,
		.height = fb->height,
		.layers = fb->layers,
	};
	for (uint32_t i = 0; i < fb->num_attachments; i++) {
		if (fb->attachments[i].external) {
			attachments[i] = 0;
			if (!strcmp (fb->attachments[i].external, "$swapchain")) {
				auto sc = ctx->swapchain;
				attachments[i] = sc->imageViews->a[ctx->swapImageIndex];
				cInfo.width = sc->extent.width;
				cInfo.height = sc->extent.height;
			}
		} else {
			attachments[i] = find_imageview (&fb->attachments[i].view, rctx);
		}
	}

	qfv_device_t *device = ctx->device;
	qfv_devfuncs_t *dfunc = device->funcs;
	VkFramebuffer framebuffer;
	dfunc->vkCreateFramebuffer (device->dev, &cInfo, 0, &framebuffer);
	QFV_duSetObjectName (device, VK_OBJECT_TYPE_FRAMEBUFFER, framebuffer,
						 va (ctx->va_ctx, "framebuffer:%s", rp->label.name));

	rp->beginInfo.framebuffer = framebuffer;
	for (uint32_t i = 0; i < rp->subpass_count; i++) {
		__auto_type sp = &rp->subpasses[i];
		sp->inherit.framebuffer = framebuffer;
	}
}

static void
wait_on_fence (const exprval_t **params, exprval_t *result, exprctx_t *ectx)
{
	auto taskctx = (qfv_taskctx_t *) ectx;
	auto ctx = taskctx->ctx;
	auto device = ctx->device;
	auto dfunc = device->funcs;
	auto dev = device->dev;

	__auto_type frame = &ctx->frames.a[ctx->curFrame];

	dfunc->vkWaitForFences (dev, 1, &frame->fence, VK_TRUE, 2000000000);

	auto job = ctx->render_context->job;
	job->command_pool = frame->command_pool;
	dfunc->vkResetCommandPool (device->dev, job->command_pool, 0);
	DARRAY_CLEAR (&job->commands);
}

static void
renderpass_update_viewper_sissor (qfv_renderpass_t *rp,
								  const qfv_output_t *output)
{
	rp->beginInfo.renderArea.extent = output->extent;
	for (uint32_t i = 0; i < rp->subpass_count; i++) {
		auto sp = &rp->subpasses[i];
		for (uint32_t j = 0; j < sp->pipeline_count; j++) {
			auto pl = &sp->pipelines[j];
			pl->viewport.width = output->extent.width;
			pl->viewport.height = output->extent.height;
			pl->scissor.extent = output->extent;
		}
	}
}

static void
update_viewport_scissor (qfv_render_t *render, const qfv_output_t *output)
{
	for (uint32_t i = 0; i < render->num_renderpasses; i++) {
		renderpass_update_viewper_sissor (&render->renderpasses[i], output);
	}
}

static void
update_framebuffer (const exprval_t **params, exprval_t *result,
					exprctx_t *ectx)
{
	auto taskctx = (qfv_taskctx_t *) ectx;
	auto ctx = taskctx->ctx;
	auto job = ctx->render_context->job;
	auto step = QFV_GetStep (params[0], job);
	auto render = step->render;
	auto rp = render->active;

	qfv_output_t output = {};
	Vulkan_ConfigOutput (ctx, &output);
	if (output.extent.width != render->output.extent.width
		|| output.extent.height != render->output.extent.height) {
		//FIXME framebuffer image creation here
		update_viewport_scissor (render, &output);
	}

	if (!rp->beginInfo.framebuffer) {
		QFV_CreateFramebuffer (ctx, rp);
	}
}

static exprfunc_t wait_on_fence_func[] = {
	{ .func = wait_on_fence },
	{}
};

static exprtype_t *update_framebuffer_params[] = {
	&cexpr_string,
};
static exprfunc_t update_framebuffer_func[] = {
	{ .func = update_framebuffer, .num_params = 1, update_framebuffer_params },
	{}
};
static exprsym_t render_task_syms[] = {
	{ "wait_on_fence", &cexpr_function, wait_on_fence_func },
	{ "update_framebuffer", &cexpr_function, update_framebuffer_func },
	{}
};

void
QFV_Render_Init (vulkan_ctx_t *ctx)
{
	qfv_renderctx_t *rctx = calloc (1, sizeof (*rctx));
	ctx->render_context = rctx;

	exprctx_t   ectx = { .hashctx = &rctx->hashctx };
	exprsym_t   syms[] = { {} };
	rctx->task_functions.symbols = syms;
	cexpr_init_symtab (&rctx->task_functions, &ectx);
	rctx->task_functions.symbols = 0;

	QFV_Render_AddTasks (ctx, render_task_syms);
}

void
QFV_Render_Shutdown (vulkan_ctx_t *ctx)
{
	qfv_device_t *device = ctx->device;
	qfv_devfuncs_t *dfunc = device->funcs;
	__auto_type rctx = ctx->render_context;
	if (rctx->job) {
		__auto_type job = rctx->job;
		//QFV_DestroyFramebuffer (ctx); //FIXME do properly
		for (uint32_t i = 0; i < job->num_renderpasses; i++) {
			dfunc->vkDestroyRenderPass (device->dev, job->renderpasses[i], 0);
		}
		for (uint32_t i = 0; i < job->num_pipelines; i++) {
			dfunc->vkDestroyPipeline (device->dev, job->pipelines[i], 0);
		}
		for (uint32_t i = 0; i < job->num_layouts; i++) {
			dfunc->vkDestroyPipelineLayout (device->dev, job->layouts[i], 0);
		}
		if (job->resources) {
			QFV_DestroyResource (ctx->device, job->resources);
			free (job->resources);
		}
		job->command_pool = 0;
		DARRAY_CLEAR (&job->commands);
		free (rctx->job);
	}
	for (uint32_t i = 0; i < ctx->frames.size; i++) {
		auto frame = &ctx->frames.a[i];
		dfunc->vkDestroyCommandPool (device->dev, frame->command_pool, 0);
	}
	if (rctx->jobinfo) {
		__auto_type jinfo = rctx->jobinfo;
		for (uint32_t i = 0; i < jinfo->num_descriptorsetlayouts; i++) {
			__auto_type setLayout = jinfo->descriptorsetlayouts[i].setLayout;
			dfunc->vkDestroyDescriptorSetLayout (device->dev, setLayout, 0);
		}
		delete_memsuper (jinfo->memsuper);
	}
	if (rctx->task_functions.tab) {
		Hash_DelTable (rctx->task_functions.tab);
	}
	Hash_DelContext (rctx->hashctx);
}

void
QFV_Render_AddTasks (vulkan_ctx_t *ctx, exprsym_t *task_syms)
{
	__auto_type rctx = ctx->render_context;
	exprctx_t   ectx = { .hashctx = &rctx->hashctx };
	for (exprsym_t *sym = task_syms; sym->name; sym++) {
		Hash_Add (rctx->task_functions.tab, sym);
		for (exprfunc_t *f = sym->value; f->func; f++) {
			for (int i = 0; i < f->num_params; i++) {
				exprenum_t *e = f->param_types[i]->data;
				if (e && !e->symtab->tab) {
					cexpr_init_symtab (e->symtab, &ectx);
				}
			}
		}
	}
}

qfv_step_t *
QFV_GetStep (const exprval_t *param, qfv_job_t *job)
{
	// this is a little evil, but need to update the type after resolving
	// the step name
	auto stepref = (exprval_t *) param;

	// cache the render step referenced, using the parameter type as a flag
	// for whether the caching has been performed.
	if (stepref->type == &cexpr_string) {
		if (cexpr_string.size != cexpr_voidptr.size) {
			Sys_Error ("string and voidptr incompatible sizes");
		}
		auto name = *(const char **)stepref->value;
		stepref->type = &cexpr_voidptr;
		*(void **)stepref->value = 0;
		for (uint32_t i = 0; i < job->num_steps; i++) {
			auto step = &job->steps[i];
			if (!strcmp (step->label.name, name)) {
				*(void **)stepref->value = step;
				break;
			}
		}
	}
	return *(qfv_step_t **)stepref->value;
}