/*
 *  Flo's Open libRary (floor)
 *  Copyright (C) 2004 - 2026 Florian Ziesche
 *  
 *  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; version 2 of the License only.
 *  
 *  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 the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#pragma once

#include <floor/device/vulkan/vulkan_common.hpp>

#if !defined(FLOOR_NO_VULKAN)

#include <floor/device/device_queue.hpp>
#include <floor/threading/thread_safety.hpp>
#include <floor/threading/resource_slot_handler.hpp>
#include <bitset>

namespace fl {

class vulkan_command_block;
struct vulkan_queue_impl;
class vulkan_queue;
struct vulkan_command_pool_t;
struct vulkan_command_buffer_completion_impl;

//! per-thread command resource count
//! NOTE: since these are *per-thread* we are probably never going to need more than this
static constexpr const uint32_t vulkan_thread_resource_count { 64u };

struct vulkan_command_buffer {
	VkCommandBuffer cmd_buffer { nullptr };
	const char* name { nullptr };
	uint8_t index { resource_slot_handler<vulkan_thread_resource_count>::invalid_slot_idx };
	bool is_secondary { false };
	
	vulkan_command_buffer() = default;
	vulkan_command_buffer(vulkan_command_buffer&& other) :
	cmd_buffer(other.cmd_buffer), name(other.name), index(other.index), is_secondary(other.is_secondary) {
		other.reset();
	}
	vulkan_command_buffer& operator=(vulkan_command_buffer&& other) {
		assert(cmd_buffer == nullptr &&
			   index == resource_slot_handler<vulkan_thread_resource_count>::invalid_slot_idx);
		cmd_buffer = other.cmd_buffer;
		name = other.name;
		index = other.index;
		is_secondary = other.is_secondary;
		other.reset();
		return *this;
	}
	
	explicit operator bool() const {
		return (cmd_buffer != nullptr &&
				index != resource_slot_handler<vulkan_thread_resource_count>::invalid_slot_idx);
	}
	
protected:
	friend vulkan_command_buffer_completion_impl;
	friend vulkan_queue;
	
	void reset() {
		cmd_buffer = nullptr;
		index = resource_slot_handler<vulkan_thread_resource_count>::invalid_slot_idx;
	}
};

class vulkan_queue final : public device_queue {
public:
	explicit vulkan_queue(const device& dev, VkQueue queue,
						  const uint32_t family_index, const uint32_t queue_index_, const QUEUE_TYPE queue_type_);
	~vulkan_queue() override;
	
	static void init();
	static void destroy();
	
	void finish() const override REQUIRES(!queue_lock);
	void flush() const override;
	
	void execute_indirect(const indirect_command_pipeline& indirect_cmd,
						  const indirect_execution_parameters_t& params,
						  kernel_completion_handler_f&& completion_handler) const override REQUIRES(!queue_lock);
	
	// this is synchronized elsewhere
	const void* get_queue_ptr() const override NO_THREAD_SAFETY_ANALYSIS {
		return vk_queue;
	}
	void* get_queue_ptr() override NO_THREAD_SAFETY_ANALYSIS {
		return vk_queue;
	}
	
	uint32_t get_family_index() const {
		return family_index;
	}
	
	uint32_t get_queue_index() const {
		return queue_index;
	}
	
	//! definition for a fence that should be waited on before command buffer submission
	struct wait_fence_t {
		const device_fence* fence { nullptr };
		uint64_t signaled_value { 0 };
		SYNC_STAGE stage { SYNC_STAGE::NONE };
	};
	//! encodes the specified fences as a vector of "wait_fence_t"
	static std::vector<wait_fence_t> encode_wait_fences(const std::vector<const device_fence*>& wait_fences,
														const SYNC_STAGE sync_stage);
	
	//! definition for a fence that should be signaled after command buffer execution
	struct signal_fence_t {
		device_fence* fence { nullptr };
		uint64_t unsignaled_value { 0 };
		uint64_t signaled_value { 0 };
		SYNC_STAGE stage { SYNC_STAGE::NONE };
	};
	//! encodes the specified fences as a vector of "signal_fence_t"
	static std::vector<signal_fence_t> encode_signal_fences(const std::vector<device_fence*>& signal_fences,
															const SYNC_STAGE sync_stage);
	
	vulkan_command_block make_command_block(const char* name, bool& error_signal, const bool is_blocking,
											std::vector<wait_fence_t>&& wait_fences = {},
											std::vector<signal_fence_t>&& signal_fences = {}) const;
	
	vulkan_command_buffer make_command_buffer(const char* name = nullptr) const;
	
	//! free an unsubmitted command buffer
	void free_command_buffer(vulkan_command_buffer&& cmd_buffer) const;
	
	//! submits the specified "cmd_buffer" to this queue,
	//! execution will wait until all "wait_fences" requirements are fulfilled,
	//! "signal_fences" will be signaled once their requirements are fulfilled (the cmd buffer has completed execution up to sync stage),
	//! "completion_handler" will be called once the cmd buffer fully completed execution,
	//! "blocking" signals if the function should not return until the cmd buffer has fully completed execution
	//! NOTE: ownership of "cmd_buffer", "wait_fences", "signal_fences" and "completion_handler" are transferred to this function
	//! NOTE: do not rely on the address of the cmd buffer parameter in "completion_handler", this may not be the same as the initial one
	void submit_command_buffer(vulkan_command_buffer&& cmd_buffer,
							   std::vector<wait_fence_t>&& wait_fences,
							   std::vector<signal_fence_t>&& signal_fences,
							   std::function<void(const vulkan_command_buffer&)>&& completion_handler,
							   const bool blocking = true) const REQUIRES(!queue_lock);
	
	//! creates a secondary command buffer (e.g. for use during rendering)
	vulkan_command_buffer make_secondary_command_buffer(const char* name = nullptr) const;
	
	//! executes the specified secondary command buffer within the specified primary command buffer
	//! NOTE: this transfers the ownership + will automatically hold onto the secondary command buffer until the primary has completed execution
	bool execute_secondary_command_buffer(const vulkan_command_buffer& primary_cmd_buffer,
										  vulkan_command_buffer&& secondary_cmd_buffer) const;
	
	//! completion handler type for "add_completion_handler"
	using vulkan_completion_handler_t = std::function<void()>;
	
	//! adds a completion handler to the specified command buffer that is called once the command buffer has finished execution
	//! NOTE: must be called before submit_command_buffer, otherwise this has no effect
	void add_completion_handler(const vulkan_command_buffer& cmd_buffer,
								vulkan_completion_handler_t&& completion_handler) const;
	
	void set_debug_label(const std::string& label) override REQUIRES(!queue_lock);
	
protected:
	VkQueue vk_queue GUARDED_BY(queue_lock) { nullptr };
	mutable safe_mutex queue_lock;
	const uint32_t family_index;
	const uint32_t queue_index;
	std::unique_ptr<vulkan_queue_impl> impl;
	
	friend vulkan_command_pool_t;
	friend vulkan_queue_impl;
	
};

//! command buffer block that will automatically start the cmd buffer on construction and end + submit it on destruction
class vulkan_command_block {
public:
	vulkan_command_buffer cmd_buffer {};
	
	vulkan_command_block(const vulkan_queue& vk_queue, const char* name, bool& error_signal, const bool is_blocking,
						 std::vector<vulkan_queue::wait_fence_t>&& wait_fences = {}, std::vector<vulkan_queue::signal_fence_t>&& signal_fences = {});
	~vulkan_command_block();
	
	bool valid { false };
	explicit operator bool() const {
		return valid;
	}
	
protected:
	const vulkan_queue& vk_queue;
	bool& error_signal;
	const bool is_blocking { true };
	
	std::vector<vulkan_queue::wait_fence_t> wait_fences;
	std::vector<vulkan_queue::signal_fence_t> signal_fences;
};

} // namespace fl

//! creates a "command block", i.e. creates a command buffer, starts it, runs the code specified as "...", and finally submits the buffer,
//! returns "ret" on error
#define VK_CMD_BLOCK_RET(vk_queue, name, code, ret, is_blocking, ...) \
do { \
	bool error_signal_ = false; \
	{ \
		auto cmd_block_ = (vk_queue).make_command_block(name, error_signal_, is_blocking, ##__VA_ARGS__); \
		if (!cmd_block_ || error_signal_) { \
			return ret; \
		} \
		auto& block_cmd_buffer = cmd_block_.cmd_buffer; \
		code; \
	} \
	if (error_signal_) { \
		return ret; \
	} \
} while (false)
//! creates a "command block", i.e. creates a command buffer, starts it, runs the code specified as "...", and finally submits the buffer
#define VK_CMD_BLOCK(vk_queue, name, code, is_blocking, ...) VK_CMD_BLOCK_RET(vk_queue, name, code, {}, is_blocking, ##__VA_ARGS__)

#endif
