#pragma once

#include <memory>
#include <QList>
#include <libtoken.h>
#include "libsyntax.h"

namespace ast_basic {
    // 抽象语法树 ================================================================================================
    /**
     * @brief 抽象语法树集合节点/表达式节点
     */
    class Expression {
    public:
        virtual ~Expression() = default;

        /**
         * @brief 获取表达式的解析规则
         * @return
         */
        virtual std::shared_ptr<const lib_syntax::ExpressionRule> definedRule() const = 0;

        //=====================================================
        /**
         * 获取语法节点的源码文件路径.
         * 
         * \return 文件路径
         */
        virtual QString filePath() const = 0;
        /**
         * 获取语法节点关联token序列.
         * 
         * \return token序列
         */
        virtual QList<std::shared_ptr<const lib_token::Token>> tokens() const = 0;
        virtual void tokensReset(const QList<std::shared_ptr<const lib_token::Token>> &list) = 0;
        /**
         * 解析过程中，向表达式内部添加token实例.
         * 
         * \param token_inst 实例
         */
        virtual void addToken(std::shared_ptr<const lib_token::Token> token_inst) = 0;

        //=====================================================
        /**
         * @brief 子表达式集合
         * @return
         */
        virtual QList<std::shared_ptr<const Expression>> children() const = 0;
        /**
         * @brief 添加子表达式.
         * 
         * \param inst 子表达式实例
         */
        virtual void addChild(std::shared_ptr<const Expression> inst) = 0;
    };


    // 基础语法树构成 ==========================================================================================
    /**
     * @brief 表达式节点
     */
    class LIBSYNTAX_EXPORT ExpressionElement : public ast_basic::Expression, 
    public std::enable_shared_from_this<ExpressionElement> {
    private:
        std::shared_ptr<const lib_syntax::ExpressionRule> _expr_rule;
        QList<std::shared_ptr<const Expression>> children_store;
        QList<std::shared_ptr<const lib_token::Token>> tokens_bind;

    public:
        ExpressionElement(std::shared_ptr<const lib_syntax::ExpressionRule> bind);

        // 通过 Expression 继承
        std::shared_ptr<const lib_syntax::ExpressionRule> definedRule() const override;

        QString filePath() const override;

        QList<std::shared_ptr<const lib_token::Token>> tokens() const override;

        void tokensReset(const QList<std::shared_ptr<const lib_token::Token>>& list) override;

        void addToken(std::shared_ptr<const lib_token::Token> token_inst) override;

        QList<std::shared_ptr<const Expression>> children() const override;

        void addChild(std::shared_ptr<const Expression> inst) override;
    };

    class LIBSYNTAX_EXPORT ExpressionContext : public lib_syntax::ParseContext, public std::enable_shared_from_this<ExpressionContext> {
    private:
        QList<std::shared_ptr<const lib_syntax::BaseRule>> rule_stack;
        QList<std::shared_ptr<Expression>> expression_stack;

    public:
        ExpressionContext(){}


        // 通过 ParseContext 继承
        std::shared_ptr<ast_basic::Expression> currentInst() const override;
        void pushInst(std::shared_ptr<ast_basic::Expression> current_inst) override;
        std::shared_ptr<ast_basic::Expression> popInst() override;

        std::shared_ptr<const lib_syntax::BaseRule> currentExpressionRule() const override;
        void pushExpressionRule(std::shared_ptr<const lib_syntax::BaseRule> inst) override;
        std::shared_ptr<const lib_syntax::BaseRule> popExpressionRule() override;

    };
}