#pragma once

#include <any>
#include <memory>
#include <vector>
#include <map>
#include <cassert>
#include <string_view>
#include <deque>
#include <tuple>

#include "Error.h"

#include "command_exception.h"
#include "converters/converter.h"

#ifdef WIN32
    #define __attribute__used
#else
    #define __attribute__used __attribute__((used))
#endif

namespace ts {
	/* data impl stuff */
	namespace impl {
		struct command_data;

		struct command_value {
			bool casted = false; /* true if value isn't a std::string */
			std::any value;
			std::string(*to_string)(const std::any&);
		};

		struct command_bulk {
			command_data* handle;
			std::map<std::string, std::shared_ptr<command_value>> values;
		};

		struct command_data {
			std::string command;
			bool editiable;
			std::deque<std::shared_ptr<command_bulk>> bulks;
			std::deque<std::string> triggers;
		};
	}

	/* Container stuff */
	class command_bulk;
	class command_entry;
	class command {
		public:
			struct format {
				enum value {
					QUERY,
					BRACE_ESCAPED_QUERY,
					JSON
				};
			};
			static command parse(const std::string_view& /* command data */, bool /* expect type */ = true, bool /* drop non UTF-8 characters */ = false);
			explicit command(const std::string& /* command */ = "", bool /* editable */ = true);

			std::string identifier() const;
			void set_identifier(const std::string& /* command */);

			command_bulk bulk(size_t /* bulk index */);
			const command_bulk bulk(size_t /* bulk index */) const;
			size_t bulk_count() const;
			inline command_bulk operator[](size_t /* index */);
			inline const command_bulk operator[](size_t /* index */) const;

			command_entry value(const std::string& /* key */);
			const command_entry value(const std::string& /* key */) const;
			bool has_value(const std::string& /* key */) const;
			command_entry operator[](const std::string& /* key */);
			const command_entry operator[](const std::string& /* key */) const;

			bool has_trigger(const std::string& /* key */) const;
			void set_trigger(const std::string& /* key */, bool /* value */ = true);

			std::string build(format::value /* format */ = format::QUERY);
			/* TODO add a json object build method */
		private:
			std::shared_ptr<impl::command_data> handle;
	};

	class command_bulk {
			friend class command;
		public:
			bool has(const std::string& /* key */) const;
			command_entry value(const std::string& /* key */);
			command_entry const value(const std::string& /* key */) const;


			inline command_entry operator[](const std::string& /* key */);
			inline const command_entry operator[](const std::string& /* key */) const;
		private:
			command_bulk(size_t index, std::shared_ptr<impl::command_bulk> handle) : bulk_index(index), handle(std::move(handle)) {}

			size_t bulk_index;
			std::shared_ptr<impl::command_bulk> handle;
	};

	class command_entry {
		public:
			static command_entry empty;

			command_entry() : handle(std::make_shared<impl::command_value>()) {}
			command_entry(const command_entry& ref) : handle(ref.handle) {}
			command_entry(command_entry&& ref) : handle(std::move(ref.handle)) {}

			command_entry&operator=(const command_entry& other) {
				this->handle = other.handle;
				return *this;
			}

			inline bool is_empty() const { return !this->handle->value.has_value(); }

			command_entry& reset() {
				this->handle->value.reset();
				return *this;
			}

			const std::string string() const {
				if(this->is_empty()) return "";

				if(!this->handle->casted || this->handle->value.type() == typeid(std::string)) //No cast needed
					return std::any_cast<std::string>(this->handle->value);

				if(!this->handle->to_string) throw command_cannot_uncast_exception();
				return this->handle->to_string(this->handle->value);
			}

			inline const std::string value() const { return (std::string) this->string(); }

			inline operator std::string() const {
				return this->string();
			}

			template <typename T, std::enable_if_t<!std::is_same<T, std::string>::value && !std::is_same<T, std::string>::value, int> = 0>
			T as() {
				static_assert(converter<T>::supported, "Target type isn't supported!");
				static_assert(!converter<T>::supported || converter<T>::from_string, "Target type dosn't support parsing");

				if(this->is_empty()) return T();

				if(this->handle->casted) {
					if(this->handle->value.type() == typeid(T))
						return std::any_cast<T>(this->handle->value);
					else
						throw command_casted_exception();
				} else {
					const auto& ref = std::any_cast<const std::string&>(this->handle->value);
					this->handle->value = converter<T>::from_string(ref);
					this->handle->to_string = converter<T>::to_string;
					this->handle->casted = true;
				}

				return std::any_cast<T>(this->handle->value);
			}

			template <typename T, std::enable_if_t<std::is_same<T, std::string>::value, int> = 0>
			T as() {
				return this->string();
			}

			template <typename T>
			inline operator T() {
				return this->as<T>();
			}

			command_entry& melt() {
				if(this->handle->casted) {
					this->handle->value = this->handle->to_string(this->handle->value);
					this->handle->casted = false;
					this->handle->to_string = nullptr;
				}
				return *this;
			}

			template <typename T, typename std::enable_if<!std::is_same<T, std::string>::value && !std::is_same<T, const char*>::value && !std::is_same<T, const char (&)[]>::value, int>::type = 0>
			void set(const T& value) {
				static_assert(converter<T>::supported, "Target type isn't supported!");
				static_assert(!converter<T>::supported || converter<T>::to_string, "Target type dosn't support encode");

				this->handle->casted = true;
				this->handle->value = std::move(value);
				this->handle->to_string = converter<T>::to_string;
			}

			template <typename T, typename std::enable_if<std::is_same<T, std::string>::value, int>::type = 0>
			void set(const T& value) {
				this->handle->value = value;
				this->handle->casted = false;
				this->handle->to_string = nullptr;
			}

			template <int N>
			void set(const char (&string)[N]) {
				this->set(std::string(string, N - 1));
			}

			template <typename T>
			command_entry&operator=(const T& value) {
				this->set(value);
				return *this;
			}

			explicit command_entry(std::shared_ptr<impl::command_value> handle) : handle(std::move(handle)) {}

		private:
			std::shared_ptr<impl::command_value> handle;
	};

	namespace descriptor {
		namespace tliterals {
			template <char... chars>
			using tstring = std::integer_sequence<char, chars...>;

#ifndef WIN32
			template <typename T, T... chars>
			constexpr tstring<chars...> operator""_tstr() { return { }; }
#endif
			template <typename>
			struct tliteral;

			template <char... elements>
			struct tliteral<tstring<elements...>> {
				static constexpr char string[sizeof...(elements) + 1] = { elements..., '\0' };
			};
		}

		namespace impl {
			namespace templates {
				template <bool...>
				struct _or_ {
					constexpr static bool value = false;
				};

				template <bool T, bool... Args>
				struct _or_<T, Args...> {
					constexpr static bool value = T || _or_<Args...>::value;
				};

				template <typename... >
				struct index;

				template <typename... >
				struct tuple_index;

				template <typename T, typename... R>
				struct index<T, T, R...> : std::integral_constant<size_t, 0>
				{ };

				template <typename T, typename F, typename... R>
				struct index<T, F, R...> : std::integral_constant<size_t, 1 + index<T, R...>::value>
				{ };

				template <typename T, typename... R>
				struct tuple_index<T, std::tuple<R...>> : std::integral_constant<size_t, index<T, R...>::value>
				{ };

				template <typename T>
				struct remove_cr {
					typedef T type;
				};

				template <typename T>
				struct remove_cr<const T&> {
					typedef T type;
				};
			}

			struct base;

			template <class key_t, typename value_type_t, class options, class... extends>
			struct field;

			struct field_data;
			struct field_base;
			struct optional_extend;
			struct bulk_extend;

			template <typename...>
			struct command_parser {
				constexpr static bool supported = false;
			};

			inline void parse_field(const std::shared_ptr<field_data>& description, field_base* field, command& cmd);

			struct option_data {
				bool bulked;
				bool optional;
			};

			template <bool bulked_t, bool optional_t>
			struct options {
				using object_data_t = option_data;
				static constexpr auto is_bulked = bulked_t;
				static constexpr auto is_optional = optional_t;

				protected:
					inline static object_data_t options_object() {
						return {
							is_bulked,
							is_optional
						};
					}
			};
			using default_options = options<false, false>;

			struct base { };

			struct base_data {
				int type; /* 1 = field | 2 = switch | 3 = command handle */
				option_data options;
			};

			struct field_data : public base_data {
				const char* key;
				const std::type_info& field_type;

				void* from_string;
				void* to_string;
			};

			struct field_base {
				typedef std::vector<command_entry>&(*ref_values_fn)();
				static inline std::vector<command_entry>& ref_values(const void* _this) {
					void** vtable = *(void***) _this;
					return ((ref_values_fn) vtable[0])();
				}
			};

			template <class key_t, typename value_type_t, class options, class... extends>
			struct field : public base, public options, public extends... {
				friend struct command_parser<field<key_t, value_type_t, options, extends...>>;
				static_assert(converter<value_type_t>::supported, "Target type isn't supported!");
				static_assert(!converter<value_type_t>::supported || converter<value_type_t>::from_string, "Target type dosn't support parsing");

				protected:
					using object_t = field_data;
					using value_type = value_type_t;
					static constexpr auto key = key_t::string;
					static constexpr auto from_string = converter<value_type_t>::from_string;

				public:

					template <bool flag = true /*, std::enable_if_t<!templates::_or_<std::is_same<extends, optional_extend>::value...>::value, int> = 0 */>
					using as_optional = field<key_t, value_type_t, impl::options<options::is_bulked, flag>, optional_extend, extends...>;

					template <bool flag = true /*, std::enable_if_t<!templates::_or_<std::is_same<extends, bulk_extend>::value...>::value, int> = 0 */>
					using as_bulked = field<key_t, value_type_t, impl::options<flag, options::is_optional>, bulk_extend, extends...>;

					using optional = as_optional<true>;
					using bulked = as_bulked<true>;

					inline static std::shared_ptr<object_t> describe() {
						return std::make_shared<object_t>(
							object_t {
									1,
									options::options_object(),
									key,
									typeid(value_type_t),
									(void*) converter<value_type_t>::from_string,
									(void*) converter<value_type_t>::to_string
							}
						);
					}

					inline value_type_t value() const {
						command_entry& value = this->get_command_entry();
						return value.as<value_type_t>();
					}

					inline command_entry& get_command_entry() const {
						if(this->values.empty())
							throw command_value_missing_exception{0, key};

						const auto& front = this->values.front();
						return *(command_entry*) &front;
					}

					template <typename T>
					inline T as() const {
						command_entry& value = this->get_command_entry();
						return value.as<T>();
					}

					template <typename T>
					inline operator T() const {
						return this->as<T>();
					}

				protected:
					/* ATTENTION: This must be placed at index 0 within the VTable */
					virtual __attribute__used std::vector<command_entry>& _v_ref_values() {
						return this->values;
					}

					std::vector<command_entry> values;
			};

			struct optional_extend {
				public:
					inline bool has_value() const {
						auto& values = field_base::ref_values(this);
						return !values.empty() && !values[0].is_empty();
					}

					template <typename T>
					inline T get_or(T&& value = T{}) const {
						if(this->has_value())
							return field_base::ref_values(this).front().as<T>();
						return value;
					}
			};

			struct bulk_extend {
				public:
					inline bool has_index(size_t index) const {
						return !this->at(index).is_empty();
					}

					inline size_t length() const { return field_base::ref_values(this).size(); }

					inline command_entry at(size_t index) const {
						auto& values = field_base::ref_values(this);
						if(index > values.size())
							throw command_bulk_exceed_index_exception();

						return values[index];
					}

					inline command_entry operator[](size_t index) const {
						return this->at(index);
					}
			};

			struct trigger_data : public base_data {
				const char* key;
			};

			struct trigger_base : public base {
				typedef bool&(*ref_flag_fn)();
				static inline bool& ref_flag(void* _this) {
					void** vtable = *(void***) _this;
					return ((ref_flag_fn) vtable[0])();
				}
			};

			template <class key_t, class options>
			struct trigger : public trigger_base, public options {
				protected:
					static constexpr auto key = key_t::string;
				public:
					using object_t = trigger_data;

					inline static std::shared_ptr<object_t> describe() {
						return std::make_shared<object_t>(
							object_t {
									2,
									options::options_object(),
									key
							}
						);
					}

					inline bool is_set() const { return this->flag_set; }
					operator bool() const { return this->flag_set; }

				private:
					/* ATTENTION: This must be placed at index 0 within the VTable */
					virtual __attribute__used bool& _v_ref_values() {
						return this->flag_set;
					}

					bool flag_set;
			};

			struct command_handle_data : public base_data { };

			struct command_handle_base : public base {
				typedef command&(*ref_flag_fn)();
				static inline command& ref_command(void* _this) {
					void** vtable = *(void***) _this;
					return ((ref_flag_fn) vtable[0])();
				}
			};

			template <class options>
			struct command_handle : public command_handle_base, public options {
				public:
					using object_t = command_handle_data;
					inline static std::shared_ptr<object_t> describe() {
						return std::make_shared<object_t>(
								command_handle_data {
										3,
										options::options_object()
								}
						);
					}

					inline command get_command() { return this->_command; }
					operator command() { return this->_command; }

					inline command* operator->() const noexcept {
						return (command*) &_command;
					}

					/*
					template<class Arg>
					auto operator[](Arg &&arg) -> decltype(get_command()[std::forward<Arg>(arg)]) {
						return _command[std::forward<Arg>(arg)];
					}
					 */
					template<class Arg>
					decltype(std::declval<command>()[std::forward<Arg>(Arg{})]) operator[](Arg &&arg) {
						return _command[std::forward<Arg>(arg)];
					}
				private:
					/* ATTENTION: This must be placed at index 0 within the VTable */
					virtual __attribute__used class command& _v_ref_values() {
						return this->_command;
					}

					command _command;
			};

			typedef std::vector<std::shared_ptr<impl::base_data>> function_descriptors_t;

			template <typename...>
			struct describe {
				inline static void apply(function_descriptors_t& result) {}
			};

			template <typename T, typename... Args>
			struct describe<T, Args...> {
				inline static void apply(function_descriptors_t& result) {
					result.push_back(T::describe());
					describe<Args...>::apply(result);
				}
			};

			inline void parse_field(const std::shared_ptr<field_data>& description, void* field, command& cmd) {
				//if(!description->options.optional && !cmd.has_value(description->key))
				//	throw command_value_missing_exception();

				auto& values = field_base::ref_values(field);
				values.clear();

				if(description->options.bulked) {
					values.resize(cmd.bulk_count());
					for(size_t bulk_index = 0; bulk_index < cmd.bulk_count(); bulk_index++) {
						if(!cmd[bulk_index].has(description->key)) {
							if(!description->options.optional)
								throw command_value_missing_exception(bulk_index, description->key);
							else
								values[bulk_index] = command_entry::empty;
						} else {
							values[bulk_index] = cmd[bulk_index][description->key];
						}
					}
				} else {
					if(!cmd.has_value(description->key)) {
						if(!description->options.optional)
							throw command_value_missing_exception(0, description->key);
						else
						values.push_back(command_entry::empty);
					} else
						values.push_back(cmd[description->key]);
				}
			}

			template <class key_t, class options, class... extends>
			struct command_parser<field<key_t, options, extends...>> {
				constexpr static bool supported = true;

				typedef field<key_t, options, extends...> field_t;
				using descriptor_t = std::shared_ptr<typename field_t::object_t>;

				inline static descriptor_t describe() {
					return field_t::describe();
				}

				inline static field_t apply(descriptor_t& descriptor, command& cmd) {
					assert(descriptor->type == 1);

					field_t result{};
					parse_field(descriptor, (void*) &result, cmd);

					return result;
				}
			};

			template <typename key_t, class options>
			struct command_parser<trigger<key_t, options>> {
				constexpr static bool supported = true;

				typedef trigger<key_t, options> trigger_t;
				using descriptor_t = std::shared_ptr<typename trigger_t::object_t>;

				inline static descriptor_t describe() {
					return trigger_t::describe();
				}

				inline static trigger_t apply(descriptor_t& descriptor, command& cmd) {
					assert(descriptor->type == 2);

					trigger_t result{};
					trigger_base::ref_flag(&result) = cmd.has_trigger(descriptor->key);
					return result;
				}
			};

			template <class options>
			struct command_parser<command_handle<options>> {
				constexpr static bool supported = true;

				typedef command_handle<options> command_handle_t;
				using descriptor_t = std::shared_ptr<typename command_handle_t::object_t>;

				inline static descriptor_t describe() {
					return command_handle_t::describe();
				}

				inline static command_handle_t apply(descriptor_t& descriptor, command& cmd) {
					assert(descriptor->type == 3);

					command_handle_t result{};
					command_handle_base::ref_command(&result) = cmd;
					return result;
				}
			};

			template <typename C>
			struct command_parser<C> {
				constexpr static bool supported = std::is_same<typename std::remove_reference<typename std::remove_cv<C>::type>::type, command>::value;
				static_assert(supported, "This type isn't supported!");

				using descriptor_t = std::shared_ptr<void>;

				inline static descriptor_t describe() {
					return nullptr;
				}

				inline static command& apply(descriptor_t& descriptor, command& cmd) {
					return cmd;
				}
			};
		}

		/* direct use of command is possible as well! */
		using command_handle = impl::command_handle<impl::default_options>;

		template <class key_t, typename value_type_t>
		using field = impl::field<key_t, value_type_t, impl::default_options>;

		template <class key_t>
		using trigger = impl::trigger<key_t, impl::default_options>;

		template <typename... args_t>
		inline impl::function_descriptors_t describe_function() {
			impl::function_descriptors_t result;
			impl::describe<args_t...>::apply(result);
			return result;
		}

		struct invocable_function {
			void operator()(command& command) {
				this->invoke(command);
			}

			virtual void invoke(command& command) = 0;
		};

		template <typename... args_t>
		struct typed_invocable_function : public invocable_function {
			using args_tuple_t = std::tuple<args_t...>;
			template <typename arg_t>
			using command_parser_t = impl::command_parser<typename impl::templates::remove_cr<arg_t>::type>;
			using descriptors_t = std::tuple<typename command_parser_t<args_t>::descriptor_t...>;

			descriptors_t descriptors;
			void(*function)(args_t...);

			void invoke(command& command) override {
				function(command_parser_t<args_t>::apply(std::get<impl::templates::tuple_index<args_t, args_tuple_t>::value>(descriptors), command)...);
			}
		};

		template <typename... args_t, typename typed_function = typed_invocable_function<args_t...>>
		std::shared_ptr<invocable_function> parse_function(void(*function)(args_t...)) {
			auto result = std::make_shared<typed_function>();
			result->function = function;
			result->descriptors = {impl::command_parser<typename impl::templates::remove_cr<args_t>::type>::describe()...};
			return result;
		}

		template <typename... args_t>
		void invoke_function(void(*function)(args_t...), command& command) {
			auto descriptor = parse_function(function);
			(*descriptor)(command);
		}

		/* converts a literal into a template literal */
		#define _tlit(literal) ::ts::descriptor::tliterals::tliteral<decltype(literal ##_tstr)>
		#define tl(lit) _tlit(lit)
	}

	//using desc = descriptor::base<descriptor::impl::default_options>;
}

#include "command_internal.h"