/**************************************************************************/
/*  metal_objects_shared.h                                                */
/**************************************************************************/
/*                         This file is part of:                          */
/*                             GODOT ENGINE                               */
/*                        https://godotengine.org                         */
/**************************************************************************/
/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
/*                                                                        */
/* Permission is hereby granted, free of charge, to any person obtaining  */
/* a copy of this software and associated documentation files (the        */
/* "Software"), to deal in the Software without restriction, including    */
/* without limitation the rights to use, copy, modify, merge, publish,    */
/* distribute, sublicense, and/or sell copies of the Software, and to     */
/* permit persons to whom the Software is furnished to do so, subject to  */
/* the following conditions:                                              */
/*                                                                        */
/* The above copyright notice and this permission notice shall be         */
/* included in all copies or substantial portions of the Software.        */
/*                                                                        */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,        */
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/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
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/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,   */
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/**************************************************************************/

#pragma once

#import "metal_device_properties.h"
#import "metal_utils.h"

using RDC = RenderingDeviceCommons;

// These types can be used in Vector and other containers that use
// pointer operations not supported by ARC.
namespace MTL {
#define MTL_CLASS(name)                               \
	class name {                                      \
	public:                                           \
		name(id<MTL##name> obj = nil) : m_obj(obj) {} \
		operator id<MTL##name>() const {              \
			return m_obj;                             \
		}                                             \
		id<MTL##name> m_obj;                          \
	};

MTL_CLASS(Texture)

} //namespace MTL

enum ShaderStageUsage : uint32_t {
	None = 0,
	Vertex = RDD::SHADER_STAGE_VERTEX_BIT,
	Fragment = RDD::SHADER_STAGE_FRAGMENT_BIT,
	TesselationControl = RDD::SHADER_STAGE_TESSELATION_CONTROL_BIT,
	TesselationEvaluation = RDD::SHADER_STAGE_TESSELATION_EVALUATION_BIT,
	Compute = RDD::SHADER_STAGE_COMPUTE_BIT,
};

_FORCE_INLINE_ ShaderStageUsage &operator|=(ShaderStageUsage &p_a, int p_b) {
	p_a = ShaderStageUsage(uint32_t(p_a) | uint32_t(p_b));
	return p_a;
}

struct ClearAttKey {
	const static uint32_t COLOR_COUNT = MAX_COLOR_ATTACHMENT_COUNT;
	const static uint32_t DEPTH_INDEX = COLOR_COUNT;
	const static uint32_t STENCIL_INDEX = DEPTH_INDEX + 1;
	const static uint32_t ATTACHMENT_COUNT = STENCIL_INDEX + 1;

	enum Flags : uint16_t {
		CLEAR_FLAGS_NONE = 0,
		CLEAR_FLAGS_LAYERED = 1 << 0,
	};

	Flags flags = CLEAR_FLAGS_NONE;
	uint16_t sample_count = 0;
	uint16_t pixel_formats[ATTACHMENT_COUNT] = { 0 };

	_FORCE_INLINE_ void set_color_format(uint32_t p_idx, MTLPixelFormat p_fmt) { pixel_formats[p_idx] = p_fmt; }
	_FORCE_INLINE_ void set_depth_format(MTLPixelFormat p_fmt) { pixel_formats[DEPTH_INDEX] = p_fmt; }
	_FORCE_INLINE_ void set_stencil_format(MTLPixelFormat p_fmt) { pixel_formats[STENCIL_INDEX] = p_fmt; }
	_FORCE_INLINE_ MTLPixelFormat depth_format() const { return (MTLPixelFormat)pixel_formats[DEPTH_INDEX]; }
	_FORCE_INLINE_ MTLPixelFormat stencil_format() const { return (MTLPixelFormat)pixel_formats[STENCIL_INDEX]; }
	_FORCE_INLINE_ void enable_layered_rendering() { flags::set(flags, CLEAR_FLAGS_LAYERED); }

	_FORCE_INLINE_ bool is_enabled(uint32_t p_idx) const { return pixel_formats[p_idx] != 0; }
	_FORCE_INLINE_ bool is_depth_enabled() const { return pixel_formats[DEPTH_INDEX] != 0; }
	_FORCE_INLINE_ bool is_stencil_enabled() const { return pixel_formats[STENCIL_INDEX] != 0; }
	_FORCE_INLINE_ bool is_layered_rendering_enabled() const { return flags::any(flags, CLEAR_FLAGS_LAYERED); }

	_FORCE_INLINE_ bool operator==(const ClearAttKey &p_rhs) const {
		return memcmp(this, &p_rhs, sizeof(ClearAttKey)) == 0;
	}

	uint32_t hash() const {
		uint32_t h = hash_murmur3_one_32(flags);
		h = hash_murmur3_one_32(sample_count, h);
		h = hash_murmur3_buffer(pixel_formats, ATTACHMENT_COUNT * sizeof(pixel_formats[0]), h);
		return hash_fmix32(h);
	}
};

/**
 * Returns an index that can be used to map a shader stage to an index in a fixed-size array that is used for
 * a single pipeline type.
 */
_FORCE_INLINE_ static uint32_t to_index(RDD::ShaderStage p_s) {
	switch (p_s) {
		case RenderingDeviceCommons::SHADER_STAGE_VERTEX:
		case RenderingDeviceCommons::SHADER_STAGE_TESSELATION_CONTROL:
		case RenderingDeviceCommons::SHADER_STAGE_TESSELATION_EVALUATION:
		case RenderingDeviceCommons::SHADER_STAGE_COMPUTE:
		default:
			return 0;
		case RenderingDeviceCommons::SHADER_STAGE_FRAGMENT:
			return 1;
	}
}

class API_AVAILABLE(macos(11.0), ios(14.0), tvos(14.0)) MDFrameBuffer {
	Vector<MTL::Texture> textures;

public:
	Size2i size;
	MDFrameBuffer(Vector<MTL::Texture> p_textures, Size2i p_size) :
			textures(p_textures), size(p_size) {}
	MDFrameBuffer() {}

	/// Returns the texture at the given index.
	_ALWAYS_INLINE_ MTL::Texture get_texture(uint32_t p_idx) const {
		return textures[p_idx];
	}

	/// Returns true if the texture at the given index is not nil.
	_ALWAYS_INLINE_ bool has_texture(uint32_t p_idx) const {
		return textures[p_idx] != nil;
	}

	/// Set the texture at the given index.
	_ALWAYS_INLINE_ void set_texture(uint32_t p_idx, MTL::Texture p_texture) {
		textures.write[p_idx] = p_texture;
	}

	/// Unset or nil the texture at the given index.
	_ALWAYS_INLINE_ void unset_texture(uint32_t p_idx) {
		textures.write[p_idx] = nil;
	}

	/// Resizes buffers to the specified size.
	_ALWAYS_INLINE_ void set_texture_count(uint32_t p_size) {
		textures.resize(p_size);
	}

	virtual ~MDFrameBuffer() = default;
};

// These functions are used to convert between Objective-C objects and
// the RIDs used by Godot, respecting automatic reference counting.
namespace rid {

// Converts an Objective-C object to a pointer, and incrementing the
// reference count.
_FORCE_INLINE_ void *owned(id p_id) {
	return (__bridge_retained void *)p_id;
}

#define MAKE_ID(FROM, TO)                \
	_FORCE_INLINE_ TO make(FROM p_obj) { \
		return TO(owned(p_obj));         \
	}

// These are shared for Metal and Metal 4 drivers

MAKE_ID(id<MTLTexture>, RDD::TextureID)
MAKE_ID(id<MTLBuffer>, RDD::BufferID)
MAKE_ID(id<MTLSamplerState>, RDD::SamplerID)
MAKE_ID(MTLVertexDescriptor *, RDD::VertexFormatID)

#undef MAKE_ID

// Converts a pointer to an Objective-C object without changing the reference count.
_FORCE_INLINE_ auto get(RDD::ID p_id) {
	return (p_id.id) ? (__bridge ::id)(void *)p_id.id : nil;
}

// Converts a pointer to an Objective-C object, and decrements the reference count.
_FORCE_INLINE_ auto release(RDD::ID p_id) {
	return (__bridge_transfer ::id)(void *)p_id.id;
}

} // namespace rid