/* SPDX-License-Identifier: BSD-3-Clause */
/* SPDX-FileCopyrightText: OpenMPT Project Developers and Contributors */

/*
 * Originally based on <http://stackoverflow.com/questions/4226960/type-safer-bitflags-in-c>.
 * Rewritten to be standard-conforming.
 */


#pragma once

#include "openmpt/all/BuildSettings.hpp"

#include "mpt/base/macros.hpp"

#include <type_traits>

#include <cstddef>


OPENMPT_NAMESPACE_BEGIN


// Type-safe wrapper around an enum, that can represent all enum values and bitwise compositions thereof.
// Conversions to and from plain integers as well as conversions to the base enum are always explicit.
template <typename enum_t>
// cppcheck-suppress copyCtorAndEqOperator
class enum_value_type
{
public:
	using enum_type = enum_t;
	using value_type = enum_value_type;
	using store_type = typename std::make_unsigned<enum_t>::type;

private:
	store_type bits;

public:
	MPT_CONSTEXPRINLINE enum_value_type() noexcept
		: bits(0) {}
	MPT_CONSTEXPRINLINE enum_value_type(const enum_value_type &x) noexcept
		: bits(x.bits) {}
	MPT_CONSTEXPRINLINE enum_value_type(enum_type x) noexcept
		: bits(static_cast<store_type>(x)) {}

private:
	explicit MPT_CONSTEXPRINLINE enum_value_type(store_type x) noexcept
		: bits(x) {}                                                           // private in order to prevent accidental conversions. use from_bits.
	MPT_CONSTEXPRINLINE operator store_type() const noexcept { return bits; }  // private in order to prevent accidental conversions. use as_bits.
public:
	static MPT_CONSTEXPRINLINE enum_value_type from_bits(store_type bits) noexcept { return value_type(bits); }
	MPT_CONSTEXPRINLINE enum_type as_enum() const noexcept { return static_cast<enum_t>(bits); }
	MPT_CONSTEXPRINLINE store_type as_bits() const noexcept { return bits; }

public:
	MPT_CONSTEXPRINLINE operator bool() const noexcept { return bits != store_type(); }
	MPT_CONSTEXPRINLINE bool operator!() const noexcept { return bits == store_type(); }

	MPT_CONSTEXPRINLINE const enum_value_type operator~() const noexcept { return enum_value_type(~bits); }

	friend MPT_CONSTEXPRINLINE bool operator==(enum_value_type a, enum_value_type b) noexcept { return a.bits == b.bits; }
	friend MPT_CONSTEXPRINLINE bool operator!=(enum_value_type a, enum_value_type b) noexcept { return a.bits != b.bits; }

	friend MPT_CONSTEXPRINLINE bool operator==(enum_value_type a, enum_t b) noexcept { return a == enum_value_type(b); }
	friend MPT_CONSTEXPRINLINE bool operator!=(enum_value_type a, enum_t b) noexcept { return a != enum_value_type(b); }

	friend MPT_CONSTEXPRINLINE bool operator==(enum_t a, enum_value_type b) noexcept { return enum_value_type(a) == b; }
	friend MPT_CONSTEXPRINLINE bool operator!=(enum_t a, enum_value_type b) noexcept { return enum_value_type(a) != b; }

	friend MPT_CONSTEXPRINLINE const enum_value_type operator|(enum_value_type a, enum_value_type b) noexcept { return enum_value_type(a.bits | b.bits); }
	friend MPT_CONSTEXPRINLINE const enum_value_type operator&(enum_value_type a, enum_value_type b) noexcept { return enum_value_type(a.bits & b.bits); }
	friend MPT_CONSTEXPRINLINE const enum_value_type operator^(enum_value_type a, enum_value_type b) noexcept { return enum_value_type(a.bits ^ b.bits); }

	friend MPT_CONSTEXPRINLINE const enum_value_type operator|(enum_value_type a, enum_t b) noexcept { return a | enum_value_type(b); }
	friend MPT_CONSTEXPRINLINE const enum_value_type operator&(enum_value_type a, enum_t b) noexcept { return a & enum_value_type(b); }
	friend MPT_CONSTEXPRINLINE const enum_value_type operator^(enum_value_type a, enum_t b) noexcept { return a ^ enum_value_type(b); }

	friend MPT_CONSTEXPRINLINE const enum_value_type operator|(enum_t a, enum_value_type b) noexcept { return enum_value_type(a) | b; }
	friend MPT_CONSTEXPRINLINE const enum_value_type operator&(enum_t a, enum_value_type b) noexcept { return enum_value_type(a) & b; }
	friend MPT_CONSTEXPRINLINE const enum_value_type operator^(enum_t a, enum_value_type b) noexcept { return enum_value_type(a) ^ b; }

	MPT_CONSTEXPRINLINE enum_value_type &operator|=(enum_value_type b) noexcept
	{
		*this = *this | b;
		return *this;
	}
	MPT_CONSTEXPRINLINE enum_value_type &operator&=(enum_value_type b) noexcept
	{
		*this = *this & b;
		return *this;
	}
	MPT_CONSTEXPRINLINE enum_value_type &operator^=(enum_value_type b) noexcept
	{
		*this = *this ^ b;
		return *this;
	}

	MPT_CONSTEXPRINLINE enum_value_type &operator|=(enum_t b) noexcept
	{
		*this = *this | b;
		return *this;
	}
	MPT_CONSTEXPRINLINE enum_value_type &operator&=(enum_t b) noexcept
	{
		*this = *this & b;
		return *this;
	}
	MPT_CONSTEXPRINLINE enum_value_type &operator^=(enum_t b) noexcept
	{
		*this = *this ^ b;
		return *this;
	}
};


// Type-safe enum wrapper that allows type-safe bitwise testing.
template <typename enum_t>
class Enum
{
public:
	using self_type = Enum;
	using enum_type = enum_t;
	using value_type = enum_value_type<enum_t>;
	using store_type = typename value_type::store_type;

private:
	enum_type value;

public:
	explicit MPT_CONSTEXPRINLINE Enum(enum_type val) noexcept
		: value(val) {}
	MPT_CONSTEXPRINLINE operator enum_type() const noexcept { return value; }
	MPT_CONSTEXPRINLINE Enum &operator=(enum_type val) noexcept
	{
		value = val;
		return *this;
	}

public:
	MPT_CONSTEXPRINLINE const value_type operator~() const { return ~value_type(value); }

	friend MPT_CONSTEXPRINLINE bool operator==(self_type a, self_type b) noexcept { return value_type(a) == value_type(b); }
	friend MPT_CONSTEXPRINLINE bool operator!=(self_type a, self_type b) noexcept { return value_type(a) != value_type(b); }

	friend MPT_CONSTEXPRINLINE bool operator==(self_type a, value_type b) noexcept { return value_type(a) == value_type(b); }
	friend MPT_CONSTEXPRINLINE bool operator!=(self_type a, value_type b) noexcept { return value_type(a) != value_type(b); }

	friend MPT_CONSTEXPRINLINE bool operator==(value_type a, self_type b) noexcept { return value_type(a) == value_type(b); }
	friend MPT_CONSTEXPRINLINE bool operator!=(value_type a, self_type b) noexcept { return value_type(a) != value_type(b); }

	friend MPT_CONSTEXPRINLINE bool operator==(self_type a, enum_type b) noexcept { return value_type(a) == value_type(b); }
	friend MPT_CONSTEXPRINLINE bool operator!=(self_type a, enum_type b) noexcept { return value_type(a) != value_type(b); }

	friend MPT_CONSTEXPRINLINE bool operator==(enum_type a, self_type b) noexcept { return value_type(a) == value_type(b); }
	friend MPT_CONSTEXPRINLINE bool operator!=(enum_type a, self_type b) noexcept { return value_type(a) != value_type(b); }

	friend MPT_CONSTEXPRINLINE const value_type operator|(self_type a, self_type b) noexcept { return value_type(a) | value_type(b); }
	friend MPT_CONSTEXPRINLINE const value_type operator&(self_type a, self_type b) noexcept { return value_type(a) & value_type(b); }
	friend MPT_CONSTEXPRINLINE const value_type operator^(self_type a, self_type b) noexcept { return value_type(a) ^ value_type(b); }

	friend MPT_CONSTEXPRINLINE const value_type operator|(self_type a, value_type b) noexcept { return value_type(a) | value_type(b); }
	friend MPT_CONSTEXPRINLINE const value_type operator&(self_type a, value_type b) noexcept { return value_type(a) & value_type(b); }
	friend MPT_CONSTEXPRINLINE const value_type operator^(self_type a, value_type b) noexcept { return value_type(a) ^ value_type(b); }

	friend MPT_CONSTEXPRINLINE const value_type operator|(value_type a, self_type b) noexcept { return value_type(a) | value_type(b); }
	friend MPT_CONSTEXPRINLINE const value_type operator&(value_type a, self_type b) noexcept { return value_type(a) & value_type(b); }
	friend MPT_CONSTEXPRINLINE const value_type operator^(value_type a, self_type b) noexcept { return value_type(a) ^ value_type(b); }

	friend MPT_CONSTEXPRINLINE const value_type operator|(self_type a, enum_type b) noexcept { return value_type(a) | value_type(b); }
	friend MPT_CONSTEXPRINLINE const value_type operator&(self_type a, enum_type b) noexcept { return value_type(a) & value_type(b); }
	friend MPT_CONSTEXPRINLINE const value_type operator^(self_type a, enum_type b) noexcept { return value_type(a) ^ value_type(b); }

	friend MPT_CONSTEXPRINLINE const value_type operator|(enum_type a, self_type b) noexcept { return value_type(a) | value_type(b); }
	friend MPT_CONSTEXPRINLINE const value_type operator&(enum_type a, self_type b) noexcept { return value_type(a) & value_type(b); }
	friend MPT_CONSTEXPRINLINE const value_type operator^(enum_type a, self_type b) noexcept { return value_type(a) ^ value_type(b); }
};


template <typename enum_t, typename store_t = typename enum_value_type<enum_t>::store_type>
// cppcheck-suppress copyCtorAndEqOperator
class FlagSet
{
public:
	using self_type = FlagSet;
	using enum_type = enum_t;
	using value_type = enum_value_type<enum_t>;
	using store_type = store_t;

private:
	// support truncated store_type ... :
	store_type bits_;
	static MPT_CONSTEXPRINLINE store_type store_from_value(value_type bits) noexcept { return static_cast<store_type>(bits.as_bits()); }
	static MPT_CONSTEXPRINLINE value_type value_from_store(store_type bits) noexcept { return value_type::from_bits(static_cast<typename value_type::store_type>(bits)); }

	MPT_CONSTEXPRINLINE FlagSet &store(value_type bits) noexcept
	{
		bits_ = store_from_value(bits);
		return *this;
	}
	MPT_CONSTEXPRINLINE value_type load() const noexcept { return value_from_store(bits_); }

public:
	// Default constructor (no flags set)
	MPT_CONSTEXPRINLINE FlagSet() noexcept
		: bits_(store_from_value(value_type()))
	{
	}

	// Copy constructor
	MPT_CONSTEXPRINLINE FlagSet(const FlagSet &flags) noexcept
		: bits_(flags.bits_)
	{
	}

	// Value constructor
	MPT_CONSTEXPRINLINE FlagSet(value_type flags) noexcept
		: bits_(store_from_value(value_type(flags)))
	{
	}

	MPT_CONSTEXPRINLINE FlagSet(enum_type flag) noexcept
		: bits_(store_from_value(value_type(flag)))
	{
	}

	explicit MPT_CONSTEXPRINLINE FlagSet(store_type flags) noexcept
		: bits_(store_from_value(value_type::from_bits(flags)))
	{
	}

	MPT_CONSTEXPRINLINE explicit operator bool() const noexcept
	{
		return load();
	}
	MPT_CONSTEXPRINLINE explicit operator store_type() const noexcept
	{
		return load().as_bits();
	}

	MPT_CONSTEXPRINLINE value_type value() const noexcept
	{
		return load();
	}

	MPT_CONSTEXPRINLINE operator value_type() const noexcept
	{
		return load();
	}

	// Test if one or more flags are set. Returns true if at least one of the given flags is set.
	MPT_CONSTEXPRINLINE bool operator[](value_type flags) const noexcept
	{
		return test(flags);
	}

	// Set one or more flags.
	MPT_CONSTEXPRINLINE FlagSet &set(value_type flags) noexcept
	{
		return store(load() | flags);
	}

	// Set or clear one or more flags.
	MPT_CONSTEXPRINLINE FlagSet &set(value_type flags, bool val) noexcept
	{
		return store((val ? (load() | flags) : (load() & ~flags)));
	}

	// Clear or flags.
	MPT_CONSTEXPRINLINE FlagSet &reset() noexcept
	{
		return store(value_type());
	}

	// Clear one or more flags.
	MPT_CONSTEXPRINLINE FlagSet &reset(value_type flags) noexcept
	{
		return store(load() & ~flags);
	}

	// Toggle all flags.
	MPT_CONSTEXPRINLINE FlagSet &flip() noexcept
	{
		return store(~load());
	}

	// Toggle one or more flags.
	MPT_CONSTEXPRINLINE FlagSet &flip(value_type flags) noexcept
	{
		return store(load() ^ flags);
	}

	// Returns the size of the flag set in bytes
	MPT_CONSTEXPRINLINE std::size_t size() const noexcept
	{
		return sizeof(store_type);
	}

	// Returns the size of the flag set in bits
	MPT_CONSTEXPRINLINE std::size_t size_bits() const noexcept
	{
		return size() * 8;
	}

	// Test if one or more flags are set. Returns true if at least one of the given flags is set.
	MPT_CONSTEXPRINLINE bool test(value_type flags) const noexcept
	{
		return (load() & flags);
	}

	// Test if all specified flags are set.
	MPT_CONSTEXPRINLINE bool test_all(value_type flags) const noexcept
	{
		return (load() & flags) == flags;
	}

	// Test if any but the specified flags are set.
	MPT_CONSTEXPRINLINE bool test_any_except(value_type flags) const noexcept
	{
		return (load() & ~flags);
	}

	// Test if any flag is set.
	MPT_CONSTEXPRINLINE bool any() const noexcept
	{
		return load();
	}

	// Test if no flags are set.
	MPT_CONSTEXPRINLINE bool none() const noexcept
	{
		return !load();
	}

	MPT_CONSTEXPRINLINE store_type GetRaw() const noexcept
	{
		return bits_;
	}

	MPT_CONSTEXPRINLINE FlagSet &SetRaw(store_type flags) noexcept
	{
		bits_ = flags;
		return *this;
	}

	MPT_CONSTEXPRINLINE FlagSet &operator=(value_type flags) noexcept
	{
		return store(flags);
	}

	MPT_CONSTEXPRINLINE FlagSet &operator=(enum_type flag) noexcept
	{
		return store(flag);
	}

	MPT_CONSTEXPRINLINE FlagSet &operator=(FlagSet flags) noexcept
	{
		return store(flags.load());
	}

	MPT_CONSTEXPRINLINE FlagSet &operator&=(value_type flags) noexcept
	{
		return store(load() & flags);
	}

	MPT_CONSTEXPRINLINE FlagSet &operator|=(value_type flags) noexcept
	{
		return store(load() | flags);
	}

	MPT_CONSTEXPRINLINE FlagSet &operator^=(value_type flags) noexcept
	{
		return store(load() ^ flags);
	}

	friend MPT_CONSTEXPRINLINE bool operator==(self_type a, self_type b) noexcept { return a.load() == b.load(); }
	friend MPT_CONSTEXPRINLINE bool operator!=(self_type a, self_type b) noexcept { return a.load() != b.load(); }

	friend MPT_CONSTEXPRINLINE bool operator==(self_type a, value_type b) noexcept { return a.load() == value_type(b); }
	friend MPT_CONSTEXPRINLINE bool operator!=(self_type a, value_type b) noexcept { return a.load() != value_type(b); }

	friend MPT_CONSTEXPRINLINE bool operator==(value_type a, self_type b) noexcept { return value_type(a) == b.load(); }
	friend MPT_CONSTEXPRINLINE bool operator!=(value_type a, self_type b) noexcept { return value_type(a) != b.load(); }

	friend MPT_CONSTEXPRINLINE bool operator==(self_type a, enum_type b) noexcept { return a.load() == value_type(b); }
	friend MPT_CONSTEXPRINLINE bool operator!=(self_type a, enum_type b) noexcept { return a.load() != value_type(b); }

	friend MPT_CONSTEXPRINLINE bool operator==(enum_type a, self_type b) noexcept { return value_type(a) == b.load(); }
	friend MPT_CONSTEXPRINLINE bool operator!=(enum_type a, self_type b) noexcept { return value_type(a) != b.load(); }

	friend MPT_CONSTEXPRINLINE bool operator==(self_type a, Enum<enum_type> b) noexcept { return a.load() == value_type(b); }
	friend MPT_CONSTEXPRINLINE bool operator!=(self_type a, Enum<enum_type> b) noexcept { return a.load() != value_type(b); }

	friend MPT_CONSTEXPRINLINE bool operator==(Enum<enum_type> a, self_type b) noexcept { return value_type(a) == b.load(); }
	friend MPT_CONSTEXPRINLINE bool operator!=(Enum<enum_type> a, self_type b) noexcept { return value_type(a) != b.load(); }

	friend MPT_CONSTEXPRINLINE const value_type operator|(self_type a, self_type b) noexcept { return a.load() | b.load(); }
	friend MPT_CONSTEXPRINLINE const value_type operator&(self_type a, self_type b) noexcept { return a.load() & b.load(); }
	friend MPT_CONSTEXPRINLINE const value_type operator^(self_type a, self_type b) noexcept { return a.load() ^ b.load(); }

	friend MPT_CONSTEXPRINLINE const value_type operator|(self_type a, value_type b) noexcept { return a.load() | value_type(b); }
	friend MPT_CONSTEXPRINLINE const value_type operator&(self_type a, value_type b) noexcept { return a.load() & value_type(b); }
	friend MPT_CONSTEXPRINLINE const value_type operator^(self_type a, value_type b) noexcept { return a.load() ^ value_type(b); }

	friend MPT_CONSTEXPRINLINE const value_type operator|(value_type a, self_type b) noexcept { return value_type(a) | b.load(); }
	friend MPT_CONSTEXPRINLINE const value_type operator&(value_type a, self_type b) noexcept { return value_type(a) & b.load(); }
	friend MPT_CONSTEXPRINLINE const value_type operator^(value_type a, self_type b) noexcept { return value_type(a) ^ b.load(); }

	friend MPT_CONSTEXPRINLINE const value_type operator|(self_type a, enum_type b) noexcept { return a.load() | value_type(b); }
	friend MPT_CONSTEXPRINLINE const value_type operator&(self_type a, enum_type b) noexcept { return a.load() & value_type(b); }
	friend MPT_CONSTEXPRINLINE const value_type operator^(self_type a, enum_type b) noexcept { return a.load() ^ value_type(b); }

	friend MPT_CONSTEXPRINLINE const value_type operator|(enum_type a, self_type b) noexcept { return value_type(a) | b.load(); }
	friend MPT_CONSTEXPRINLINE const value_type operator&(enum_type a, self_type b) noexcept { return value_type(a) & b.load(); }
	friend MPT_CONSTEXPRINLINE const value_type operator^(enum_type a, self_type b) noexcept { return value_type(a) ^ b.load(); }

	friend MPT_CONSTEXPRINLINE const value_type operator|(self_type a, Enum<enum_type> b) noexcept { return a.load() | value_type(b); }
	friend MPT_CONSTEXPRINLINE const value_type operator&(self_type a, Enum<enum_type> b) noexcept { return a.load() & value_type(b); }
	friend MPT_CONSTEXPRINLINE const value_type operator^(self_type a, Enum<enum_type> b) noexcept { return a.load() ^ value_type(b); }

	friend MPT_CONSTEXPRINLINE const value_type operator|(Enum<enum_type> a, self_type b) noexcept { return value_type(a) | b.load(); }
	friend MPT_CONSTEXPRINLINE const value_type operator&(Enum<enum_type> a, self_type b) noexcept { return value_type(a) & b.load(); }
	friend MPT_CONSTEXPRINLINE const value_type operator^(Enum<enum_type> a, self_type b) noexcept { return value_type(a) ^ b.load(); }
};


// Declare typesafe logical operators for enum_t
#define MPT_DECLARE_ENUM(enum_t) \
	MPT_CONSTEXPRINLINE enum_value_type<enum_t> operator|(enum_t a, enum_t b) noexcept { return enum_value_type<enum_t>(a) | enum_value_type<enum_t>(b); } \
	MPT_CONSTEXPRINLINE enum_value_type<enum_t> operator&(enum_t a, enum_t b) noexcept { return enum_value_type<enum_t>(a) & enum_value_type<enum_t>(b); } \
	MPT_CONSTEXPRINLINE enum_value_type<enum_t> operator^(enum_t a, enum_t b) noexcept { return enum_value_type<enum_t>(a) ^ enum_value_type<enum_t>(b); } \
	MPT_CONSTEXPRINLINE enum_value_type<enum_t> operator~(enum_t a) noexcept { return ~enum_value_type<enum_t>(a); } \
/**/

// backwards compatibility
#define DECLARE_FLAGSET MPT_DECLARE_ENUM


OPENMPT_NAMESPACE_END
