manafiles/src/util/format/formatter.h

/*
 * Copyright (C) 2022 Riyyi
 *
 * SPDX-License-Identifier: MIT
 */

#pragma once

#include <cassert>
#include <cstddef> // size_t
#include <cstdint> // int8_t, uint8_t, uintptr_t
#include <map>
#include <string>
#include <string_view>
#include <type_traits> // is_integral_v, is_same
#include <unordered_map>
#include <vector>

#include "util/format/builder.h"
#include "util/format/parser.h"
#include "util/meta/concepts.h"

namespace Util::Format {

enum class PresentationType : uint8_t {
	None,
	// Interger
	Binary = 'b',
	BinaryUppercase = 'B',
	Decimal = 'd',
	Octal = 'o',
	Hex = 'x',
	HexUppercase = 'X',
	// Floating-point
	Hexfloat = 'a',
	HexfloatUppercase = 'A',
	Exponent = 'e',
	ExponentUppercase = 'E',
	FixedPoint = 'f',
	FixedPointUppercase = 'F',
	General = 'g',
	GeneralUppercase = 'G',
	// Character
	Character = 'c',
	// String
	String = 's',
	// Pointer
	Pointer = 'p',
	// Container
	Container = 'C',
};

struct Specifier {
	char fill = ' ';
	Builder::Align align = Builder::Align::None;

	Builder::Sign sign = Builder::Sign::None;

	bool alternativeForm = false;
	bool zeroPadding = false;
	size_t width = 0;
	int8_t precision = -1;

	PresentationType type = PresentationType::None;
};

template<typename T>
struct Formatter {
	Specifier specifier;

	void parse(Parser& parser)
	{
		if constexpr (std::is_same_v<T, char>) {
			parser.parseSpecifier(specifier, Parser::ParameterType::Char);
		}
		else if (std::is_same_v<T, bool>) {
			parser.parseSpecifier(specifier, Parser::ParameterType::Char);
		}
		else if (std::is_same_v<T, std::string_view>) {
			parser.parseSpecifier(specifier, Parser::ParameterType::String);
		}
	}

	void format(Builder&, T) const {}
};

// Integral

template<Integral T>
struct Formatter<T> {
	Specifier specifier;

	void parse(Parser& parser)
	{
		parser.parseSpecifier(specifier, Parser::ParameterType::Integral);
	}

	void format(Builder& builder, T value) const
	{
		if (specifier.type == PresentationType::Character) {
			assert(value >= 0 && value <= 127);

			Formatter<std::string_view> formatter { .specifier = specifier };
			formatter.specifier.type = PresentationType::String;
			return formatter.format(builder, { reinterpret_cast<const char*>(&value), 1 });
		}

		uint8_t base = 0;
		bool uppercase = false;
		switch (specifier.type) {
		case PresentationType::BinaryUppercase:
			uppercase = true;
		case PresentationType::Binary:
			base = 2;
			break;
		case PresentationType::Octal:
			base = 8;
			break;
		case PresentationType::None:
		case PresentationType::Decimal:
			base = 10;
			break;
		case PresentationType::HexUppercase:
			uppercase = true;
		case PresentationType::Hex:
			base = 16;
			break;
		default:
			assert(false);
		};

		if constexpr (std::is_unsigned_v<T>) {
			builder.putU64(
				value, base, uppercase, specifier.fill, specifier.align, specifier.sign,
				specifier.alternativeForm, specifier.zeroPadding, specifier.width);
		}
		else {
			builder.putI64(
				value, base, uppercase, specifier.fill, specifier.align, specifier.sign,
				specifier.alternativeForm, specifier.zeroPadding, specifier.width);
		}
	}
};

// Floating point

template<FloatingPoint T>
struct Formatter<T> {
	Specifier specifier;

	void parse(Parser& parser)
	{
		parser.parseSpecifier(specifier, Parser::ParameterType::FloatingPoint);
	}

	void format(Builder& builder, T value) const
	{
		if (specifier.precision < 0) {
			builder.putF64(value);
			return;
		}

		builder.putF64(value, specifier.precision);
	}
};

// Char

template<>
void Formatter<char>::format(Builder& builder, char value) const;

template<>
void Formatter<bool>::format(Builder& builder, bool value) const;

// String

template<>
void Formatter<std::string_view>::format(Builder& builder, std::string_view value) const;

template<>
struct Formatter<std::string> : Formatter<std::string_view> {
};

template<>
struct Formatter<const char*> : Formatter<std::string_view> {
	void parse(Parser& parser);
	void format(Builder& builder, const char* value) const;
};

template<>
struct Formatter<char*> : Formatter<const char*> {
};

template<size_t N>
struct Formatter<char[N]> : Formatter<const char*> {
};

// Pointer

template<typename T>
struct Formatter<T*> : Formatter<uintptr_t> {
	void parse(Parser& parser)
	{
		parser.parseSpecifier(specifier, Parser::ParameterType::Pointer);
		specifier.alternativeForm = true;
		specifier.type = PresentationType::Hex;
	}

	void format(Builder& builder, T* value) const
	{
		Formatter<uintptr_t>::format(builder, reinterpret_cast<uintptr_t>(value));
	}
};

template<>
struct Formatter<std::nullptr_t> : Formatter<const void*> {
	void format(Builder& builder, std::nullptr_t) const;
};

// Container

template<typename T>
struct Formatter<std::vector<T>> : Formatter<T> {
	Specifier specifier;

	void parse(Parser& parser)
	{
		parser.parseSpecifier(specifier, Parser::ParameterType::Container);
	}

	void format(Builder& builder, const std::vector<T>& value) const
	{
		std::string indent = std::string(specifier.width, specifier.fill);

		builder.putCharacter('{');
		if (specifier.alternativeForm) {
			builder.putCharacter('\n');
		}
		for (auto it = value.cbegin(); it != value.cend(); ++it) {
			builder.putString(indent);

			Formatter<T>::format(builder, *it);

			// Add comma, except after the last element
			if (it != std::prev(value.end(), 1)) {
				builder.putCharacter(',');
			}
			else if (!specifier.alternativeForm) {
				builder.putString(indent);
			}

			if (specifier.alternativeForm) {
				builder.putCharacter('\n');
			}
		}
		builder.putCharacter('}');
	}
};

#define UTIL_FORMAT_FORMAT_AS_MAP(type)                                         \
	template<typename K, typename V>                                            \
	struct Formatter<type<K, V>>                                                \
		: Formatter<K>                                                          \
		, Formatter<V> {                                                        \
		Specifier specifier;                                                    \
                                                                                \
		void parse(Parser& parser)                                              \
		{                                                                       \
			parser.parseSpecifier(specifier, Parser::ParameterType::Container); \
		}                                                                       \
                                                                                \
		void format(Builder& builder, const type<K, V>& value) const            \
		{                                                                       \
			std::string indent = std::string(specifier.width, specifier.fill);  \
                                                                                \
			builder.putCharacter('{');                                          \
			if (specifier.alternativeForm) {                                    \
				builder.putCharacter('\n');                                     \
			}                                                                   \
			auto last = value.end();                                            \
			for (auto it = value.begin(); it != last; ++it) {                   \
				builder.putString(indent);                                      \
				builder.putCharacter('"');                                      \
				Formatter<K>::format(builder, it->first);                       \
				builder.putCharacter('"');                                      \
				builder.putString((specifier.width > 0) ? ": " : ":");          \
				Formatter<V>::format(builder, it->second);                      \
                                                                                \
				/* Add comma, except after the last element */                  \
				if (std::next(it) != last) {                                    \
					builder.putCharacter(',');                                  \
				}                                                               \
				else if (!specifier.alternativeForm) {                          \
					builder.putString(indent);                                  \
				}                                                               \
                                                                                \
				if (specifier.alternativeForm) {                                \
					builder.putCharacter('\n');                                 \
				}                                                               \
			}                                                                   \
			builder.putCharacter('}');                                          \
		}                                                                       \
	}

UTIL_FORMAT_FORMAT_AS_MAP(std::map);
UTIL_FORMAT_FORMAT_AS_MAP(std::unordered_map);
} // namespace Util::Format