/* @file JsonPrinter.hpp
 *
 * author: Roland Conybeare, Aug 2022
 */

#pragma once

#include "xo/reflect/Reflect.hpp"
#include "xo/reflect/TypeDrivenMap.hpp"
#include "xo/reflect/TaggedPtr.hpp"
//#include <memory>
#include <iostream>

namespace xo {
    namespace json {
        class PrintJson;

        class JsonPrinter {
        public:
            using Reflect = xo::reflect::Reflect;
            using TaggedPtr = xo::reflect::TaggedPtr;
            using TypeDescr = xo::reflect::TypeDescr;
            using TypeId = xo::reflect::TypeId;

        public:
            JsonPrinter(PrintJson const * pjson) : pjson_{pjson} {}
            virtual ~JsonPrinter() = default;

            PrintJson const * pjson() const { return pjson_; }

            /* print tagged pointer in json format */
            virtual void print_json(TaggedPtr tp,
                                    std::ostream * p_os) const = 0;

            void report_internal_type_consistency_error(TypeDescr td1,
                                                        TypeDescr td2,
                                                        std::ostream * p_os) const;

            /* convenience method for derived printers.
             * retrieves contents of tp as a T*,  complains to *p_os if that fails.
             *
             * (Failure would occur if printer for type T was instead installed
             *  for some unrelated type U)
             */
            template<typename T>
            T * check_recover_native(TaggedPtr tp, std::ostream * p_os) const {
                T * x = tp.recover_native<T>();

                if (!x) {
                    this->report_internal_type_consistency_error(Reflect::require<T>(),
                                                                 tp.td(),
                                                                 p_os);
                }

                return x;
            } /*check_recover_native*/

            void assign_pjson(PrintJson const * pjson) {
                assert(this->pjson_ == nullptr || this->pjson_ == pjson);
                this->pjson_ = pjson;
            } /*assign_pjson*/

        private:
            /* a json printers is installed into one PrintJson instance;
             * capture address of that instance at install time
             */
            PrintJson const * pjson_ = nullptr;
        }; /*JsonPrinter*/

        /* AsStringJsonPrinter<T>
         * prints a T-instance by using operator<< and surrounding in quotes.
         *
         * e.g:
         *   T & x = ..;
         *   std::ostream * p_os = ..;
         *
         *   *p_os << "\"" << x << "\""
         *
         */
        template<typename T>
        class AsStringJsonPrinter : public JsonPrinter {
        public:
            AsStringJsonPrinter(PrintJson const * pjson) : JsonPrinter(pjson) {}

            virtual void print_json(TaggedPtr tp,
                                    std::ostream * p_os) const override
                {
                    T * x = this->check_recover_native<T>(tp, p_os);

                    if(x) {
                        *p_os << "\"" << *x << "\"";
                    }
                } /*print_json*/
        }; /*AsStringJsonPrinter*/
    } /*namespace json*/
} /*namespace xo*/


/* end JsonPrinter.hpp */