/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */

#pragma once

#include <any>
#include <concepts>
#include <optional>
#include <variant>

#include <react/renderer/css/CSSSyntaxParser.h>

namespace facebook::react {

class CSSValueParser;

/**
 * May be specialized to instruct the CSS value parser how to parse a given data
 * type, according to CSSValidDataTypeParser.
 */
template <typename CSSDataTypeT>
struct CSSDataTypeParser {};

/**
 * Accepts a CSS function block and may parse it into a concrete representation.
 * The CSSValueParser provides methods for parsing sub-values within the
 * function block scope.
 */
template <typename T, typename ReturnT = std::any>
concept CSSFunctionBlockSink = requires(const CSSFunctionBlock &func, CSSValueParser &parser) {
  { T::consumeFunctionBlock(func, parser) } -> std::convertible_to<ReturnT>;
};

/**
 * Accepts a CSS simple block and may parse it into a concrete representation.
 * The CSSValueParser provides methods for parsing sub-values within the
 * block scope.
 */
template <typename T, typename ReturnT = std::any>
concept CSSSimpleBlockSink = requires(const CSSSimpleBlock &block, CSSValueParser &parser) {
  { T::consumeSimpleBlock(block, parser) } -> std::convertible_to<ReturnT>;
};

/**
 * Accepts a CSS preserved token and may parse it into a concrete
 * representation.
 */
template <typename T, typename ReturnT = std::any>
concept CSSPreservedTokenSink = requires(const CSSPreservedToken &token) {
  { T::consumePreservedToken(token) } -> std::convertible_to<ReturnT>;
};

/**
 * Accepts a CSSValueParser to be able to parse compounded values spanning
 * multiple component values.
 */
template <typename T, typename ReturnT = std::any>
concept CSSParserSink = requires(CSSValueParser &parser) {
  { T::consume(parser) } -> std::convertible_to<ReturnT>;
};

/**
 * Represents a valid specialization of CSSDataTypeParser
 */
template <typename T, typename ReturnT = std::any>
concept CSSValidDataTypeParser =
    ((CSSFunctionBlockSink<T, ReturnT> || CSSSimpleBlockSink<T, ReturnT> || CSSPreservedTokenSink<T, ReturnT>) &&
     !CSSParserSink<T, ReturnT>) ||
    CSSParserSink<T, ReturnT>;

/**
 * Concrete representation for a CSS data type
 */
template <typename T>
concept CSSDataType = CSSValidDataTypeParser<CSSDataTypeParser<T>, std::optional<T>> && std::equality_comparable<T>;

} // namespace facebook::react