#pragma once

#include "libsyntax_global.h"
#include <libtoken.h>
#include <memory>
#include <tuple>
#include <functional>
namespace ast_basic {
	class Expression;
	class ExpressionElement;
}

namespace lib_syntax {
	class BaseRule;

	/**
	 * @brief 语法异常
	 */
	class SyntaxException {
	private:
		QString msg_store;

	public:
		SyntaxException(const QString& message);
		virtual ~SyntaxException() = default;

		virtual QString message() const;
	};

	// 基础语法解析接口 ===================================================================================================
	/**
	 * @brief 解析上下文接口
	 */
	class ParseContext {
	public:
		virtual ~ParseContext() = default;

		/**
		 * \brief 当前表达式元素.
		 *
		 * \return 返回当前表达式
		 */
		virtual std::shared_ptr<ast_basic::Expression> currentInst() const = 0;
		virtual void pushInst(std::shared_ptr<ast_basic::Expression> current_inst) = 0;
		virtual std::shared_ptr<ast_basic::Expression> popInst() = 0;

		virtual std::shared_ptr<const BaseRule> currentExpressionRule() const = 0;
		virtual void pushExpressionRule(std::shared_ptr<const BaseRule> inst) = 0;
		virtual std::shared_ptr<const BaseRule> popExpressionRule() = 0;
	};

	/**
	 * @brief 基础语法匹配规则接口
	 */
	class BaseRule {
	public:
		virtual ~BaseRule() = default;
		/**
		 * @brief 子规则
		 * @return
		 */
		virtual QList<std::shared_ptr<const BaseRule>> children() const = 0;

		/**
		 * @brief 匹配结果
		 */
		enum class MatchResult {
			Success, // 符合匹配条件
			Part,    // 部分匹配
			Fail     // 从第一个词起完全不匹配
		};

		/**
		 * @brief token流匹配
		 * @return 首部对齐，匹配token集合<匹配结果，匹配长度，剩余列表头指针>
		 */
		virtual std::tuple<MatchResult, uint, std::shared_ptr<const lib_token::Token>> match(std::shared_ptr<const lib_token::Token> remains_head) const = 0;

		/**
		 * @brief 解析
		 * @param rt_inst 解析上下文
		 * @param head 列表头
		 * @return 返回结果<匹配完成新列表头,匹配长度>
		 */
		virtual std::tuple<std::shared_ptr<const ast_basic::Expression>, std::shared_ptr<const lib_token::Token>>
				parse(std::shared_ptr<ParseContext> rt_inst, std::shared_ptr<const lib_token::Token> head) const = 0;

		/**
		 * 返回匹配语法规则的词法序列表达
		 *
		 * \return 词法表达序列
		 */
		virtual QString token_present() const = 0;
	};


	/**
	 * @brief token匹配
	 */
	class LIBSYNTAX_EXPORT TokenMatch : public BaseRule, public std::enable_shared_from_this<TokenMatch> {
	private:
		std::shared_ptr<const lib_token::TokenDefine> define_peer;

	public:
		TokenMatch(std::shared_ptr<const lib_token::TokenDefine> define);

		// BaseRule interface
	public:
		virtual QList<std::shared_ptr<const BaseRule>> children() const override;
		virtual std::tuple<MatchResult, uint, std::shared_ptr<const lib_token::Token>> match(std::shared_ptr<const lib_token::Token> head) const override;
		virtual std::tuple<std::shared_ptr<const ast_basic::Expression>, std::shared_ptr<const lib_token::Token>>
				parse(std::shared_ptr<ParseContext> rt_inst, std::shared_ptr<const lib_token::Token> head) const override;
		virtual QString token_present() const override;
	};

	/**
	 * @brief 语法规则或匹配
	 */
	class LIBSYNTAX_EXPORT Any : public BaseRule, public std::enable_shared_from_this<Any> {
	private:
		QList<std::shared_ptr<const BaseRule>> mbrs_store;

		std::tuple<MatchResult, uint, std::shared_ptr<const BaseRule>, std::shared_ptr<const lib_token::Token>> rule_select(std::shared_ptr<const lib_token::Token> head) const;

	public:
		Any(const QList<std::shared_ptr<const BaseRule>> mbrs);

		// BaseRule interface
	public:
		virtual QList<std::shared_ptr<const BaseRule>> children() const override;
		virtual std::tuple<MatchResult, uint, std::shared_ptr<const lib_token::Token>> match(std::shared_ptr<const lib_token::Token> list_head) const override;
		virtual std::tuple<std::shared_ptr<const ast_basic::Expression>, std::shared_ptr<const lib_token::Token>>
				parse(std::shared_ptr<ParseContext> rt_inst, std::shared_ptr<const lib_token::Token> head) const override;
		virtual QString token_present() const override;
	};

	/**
	 * @brief 语法规则序列匹配
	 */
	class LIBSYNTAX_EXPORT Seqs : public BaseRule, public std::enable_shared_from_this<Seqs> {
	private:
		QList<std::shared_ptr<const BaseRule>> mbrs_store;

	public:
		Seqs(const QList<std::shared_ptr<const BaseRule>> mbrs);

		// BaseRule interface
	public:
		virtual QList<std::shared_ptr<const BaseRule>> children() const override;
		virtual std::tuple<MatchResult, uint, std::shared_ptr<const lib_token::Token>> match(std::shared_ptr<const lib_token::Token> list_head) const override;
		virtual std::tuple<std::shared_ptr<const ast_basic::Expression>, std::shared_ptr<const lib_token::Token>>
				parse(std::shared_ptr<ParseContext> rt_inst, std::shared_ptr<const lib_token::Token> head) const override;
		virtual QString token_present() const override;
	};

	/**
	 * @brief 语法规则重复匹配
	 */
	class LIBSYNTAX_EXPORT Rept : public BaseRule, public std::enable_shared_from_this<Rept> {
	private:
		std::shared_ptr<const BaseRule> rule_peer;
		int min_match, max_match;

	public:
		Rept(std::shared_ptr<const BaseRule> rule, int min, int max);

		// BaseRule interface
	public:
		virtual QList<std::shared_ptr<const BaseRule>> children() const override;
		virtual std::tuple<MatchResult, uint, std::shared_ptr<const lib_token::Token>> match(std::shared_ptr<const lib_token::Token> list_head) const override;
		virtual std::tuple<std::shared_ptr<const ast_basic::Expression>, std::shared_ptr<const lib_token::Token>>
				parse(std::shared_ptr<ParseContext> rt_inst, std::shared_ptr<const lib_token::Token> head) const override;
		virtual QString token_present() const override;
	};

	// 组合语法实体解析 ===================================================================================================
	/**
	 * @brief 对应语法表达式解析规则
	 */
	class LIBSYNTAX_EXPORT ExpressionRule : public lib_syntax::BaseRule, public std::enable_shared_from_this<ExpressionRule> {
	public:
		typedef QList<std::shared_ptr<const lib_token::Token>> TokenSeqs;
		ExpressionRule(const QString& rule_name, int expr_mark);

		virtual std::shared_ptr<const ExpressionRule> reloadRule(std::function<TokenSeqs(const TokenSeqs&)> filter, std::shared_ptr<const BaseRule> rule);
		virtual QString name() const;
		virtual int typeMark() const;

		virtual std::shared_ptr<ast_basic::Expression> newEmptyInstance() const = 0;
		virtual std::shared_ptr<ExpressionRule> makeCopy() const = 0;

		// BaseRule interface
	public:
		virtual QList<std::shared_ptr<const lib_syntax::BaseRule>> children() const override;
		virtual std::tuple<MatchResult, uint, std::shared_ptr<const lib_token::Token>> match(std::shared_ptr<const lib_token::Token> remains_head) const override;
		virtual std::tuple<std::shared_ptr<const ast_basic::Expression>, std::shared_ptr<const lib_token::Token>>
				parse(std::shared_ptr<ParseContext> rt_inst, std::shared_ptr<const lib_token::Token> head) const override;
		virtual QString token_present() const override;

	private:
		std::function<TokenSeqs(const TokenSeqs&)> filter_proc;
		std::shared_ptr<const lib_syntax::BaseRule> child_store;
		QString name_store;
		int mark_store;
	};

	/**
	 * 语法元素解析规则.
	 */
	template<class ExprType>
	class ElementRule : public ExpressionRule {
	public:
		ElementRule(const QString& rule_name, int expr_mark)
			:ExpressionRule(rule_name, expr_mark){}

		virtual std::shared_ptr<ast_basic::Expression> newEmptyInstance() const {
			return std::dynamic_pointer_cast<ast_basic::Expression>(
				std::make_shared<ExprType>(this->shared_from_this()));
		}

		virtual std::shared_ptr<ExpressionRule> makeCopy() const {
			return std::make_shared<ElementRule<ExprType>>(name(), typeMark());
		}
	};


	class MismatchException : public SyntaxException {
	private:
		std::shared_ptr<const lib_token::Token> target;

	public:
		MismatchException(std::shared_ptr<const lib_token::Token> inst);
		virtual ~MismatchException() = default;

		virtual std::shared_ptr<const lib_token::Token> targetToken() const;
	};

	class InputTerminal : public SyntaxException {
	public:
		InputTerminal();
	};
} // namespace lib_syntax