// Glaze Library
// For the license information refer to glaze.hpp

#pragma once

#include "glaze/core/common.hpp"

// Calls a read function after reading and calls a write function before writing.
// glz::manage is useful for transforming state from a user facing format
// into a more complex or esoteric internal format.

namespace glz
{
   // manage_t invokes a function call before reading and after writing from a value
   template <class T, class Member, class From, class To>
   struct manage_t
   {
      static constexpr auto glaze_reflect = false;
      using from_t = From;
      using to_t = To;
      T& val;
      Member member;
      From from;
      To to;
   };

   template <class T, class Member, class From, class To>
   manage_t(T&, Member, From, To) -> manage_t<T, Member, From, To>;

   template <uint32_t Format, class T>
      requires(is_specialization_v<T, manage_t>)
   struct from<Format, T>
   {
      template <auto Opts>
      static void op(auto&& value, is_context auto&& ctx, auto&& it, auto&& end)
      {
         using V = std::decay_t<decltype(value)>;
         using From = typename V::from_t;

         parse<Format>::template op<Opts>(get_member(value.val, value.member), ctx, it, end);

         if constexpr (std::is_member_pointer_v<From>) {
            if constexpr (std::is_member_function_pointer_v<From>) {
               if (!(value.val.*(value.from))()) {
                  ctx.error = error_code::syntax_error;
                  return;
               }
            }
            else if constexpr (std::is_member_object_pointer_v<From>) {
               auto& from = value.val.*(value.from);
               using Func = std::decay_t<decltype(from)>;
               if constexpr (std::is_invocable_r_v<bool, Func>) {
                  if (!value.from()) {
                     ctx.error = error_code::syntax_error;
                     return;
                  }
               }
               else {
                  static_assert(false_v<T>, "function must have no arguments with a bool return");
               }
            }
            else {
               static_assert(false_v<T>, "invalid type");
            }
         }
         else {
            if (!value.from(value.val)) {
               ctx.error = error_code::syntax_error;
               return;
            }
         }
      }
   };

   template <uint32_t Format, class T>
      requires(is_specialization_v<T, manage_t>)
   struct to<Format, T>
   {
      template <auto Opts>
      static void op(auto&& value, is_context auto&& ctx, auto&&... args)
      {
         using V = std::decay_t<decltype(value)>;
         using To = typename V::to_t;

         if constexpr (std::is_member_pointer_v<To>) {
            if constexpr (std::is_member_function_pointer_v<To>) {
               if (!(value.val.*(value.to))()) {
                  ctx.error = error_code::syntax_error;
                  return;
               }
            }
            else if constexpr (std::is_member_object_pointer_v<To>) {
               auto& to = value.val.*(value.to);
               using Func = std::decay_t<decltype(to)>;
               if constexpr (std::is_invocable_r_v<bool, Func>) {
                  if (!value.to()) {
                     ctx.error = error_code::syntax_error;
                     return;
                  }
               }
               else {
                  static_assert(false_v<T>, "function must have no arguments with a bool return");
               }
            }
            else {
               static_assert(false_v<T>, "invalid type");
            }
         }
         else {
            if (!value.to(value.val)) {
               ctx.error = error_code::syntax_error;
               return;
            }
         }

         using Value = core_t<decltype(get_member(value.val, value.member))>;
         to<Format, Value>::template op<Opts>(get_member(value.val, value.member), ctx, args...);
      }
   };

   template <auto Member, auto From, auto To>
   inline constexpr decltype(auto) manage_impl()
   {
      return [](auto&& v) { return manage_t{v, Member, From, To}; };
   }

   template <auto Member, auto From, auto To>
   constexpr auto manage = manage_impl<Member, From, To>();
}
