#pragma once

#include <openvic-dataloader/v2script/AbstractSyntaxTree.hpp>

#include <lexy/_detail/config.hpp>
#include <lexy/dsl.hpp>
#include <lexy/dsl/delimited.hpp>
#include <lexy/dsl/recover.hpp>
#include <lexy/dsl/unicode.hpp>

#include "SimpleGrammar.hpp"
#include "detail/InternalConcepts.hpp"
#include "detail/dsl.hpp"

namespace ovdl::v2script::lua::grammar {
	template<typename ReturnType, typename... Callback>
	constexpr auto callback(Callback... cb) {
		return dsl::callback<ReturnType>(cb...);
	}

	template<typename T>
	constexpr auto construct = v2script::grammar::construct<T>;

	template<typename T>
	constexpr auto construct_list = v2script::grammar::construct_list<T>;

	struct StatementListBlock;

	static constexpr auto comment_specifier = LEXY_LIT("--") >> lexy::dsl::until(lexy::dsl::newline).or_eof();

	struct Identifier {
		static constexpr auto rule = lexy::dsl::identifier(lexy::dsl::ascii::alpha_underscore, lexy::dsl::ascii::alpha_digit_underscore);
		static constexpr auto value =
			callback<ast::IdentifierValue*>(
				[](detail::IsParseState auto& state, auto lexeme) {
					auto value = state.ast().intern(lexeme.data(), lexeme.size());
					return state.ast().template create<ast::IdentifierValue>(lexeme.begin(), lexeme.end(), value);
				});
	};

	struct Value {
		static constexpr auto rule = lexy::dsl::identifier(lexy::dsl::ascii::digit / lexy::dsl::lit_c<'.'> / lexy::dsl::lit_c<'-'>);
		static constexpr auto value =
			callback<ast::IdentifierValue*>(
				[](detail::IsParseState auto& state, auto lexeme) {
					auto value = state.ast().intern(lexeme.data(), lexeme.size());
					return state.ast().template create<ast::IdentifierValue>(lexeme.begin(), lexeme.end(), value);
				});
	};

	struct String : lexy::scan_production<ast::StringValue*>,
					lexy::token_production {
		template<typename Context, typename Reader>
		static constexpr scan_result scan(lexy::rule_scanner<Context, Reader>& scanner, detail::IsParseState auto& state) {
			using encoding = typename Reader::encoding;

			constexpr auto c = [] {
				if constexpr (std::same_as<encoding, lexy::default_encoding> || std::same_as<encoding, lexy::byte_encoding>) {
					// Arbitrary code points that aren't control characters.
					return dsl::lit_b_range<0x20, 0xFF> - lexy::dsl::ascii::control;
				} else {
					return -lexy::dsl::unicode::control;
				}
			}();
			auto rule = lexy::dsl::quoted(c) | lexy::dsl::single_quoted(c);
			auto begin = scanner.position();
			lexy::scan_result<std::string> str_result;
			scanner.parse(str_result, rule);
			if (!scanner || !str_result)
				return lexy::scan_failed;
			auto end = scanner.position();
			auto str = str_result.value();
			auto value = state.ast().intern(str.data(), str.size());
			return state.ast().template create<ast::StringValue>(begin, end, value);
		}

		static constexpr auto rule = lexy::dsl::peek(lexy::dsl::quoted.open() | lexy::dsl::single_quoted.open()) >> lexy::dsl::scan;
		static constexpr auto value = ovdl::v2script::grammar::convert_as_string<std::string> >> lexy::forward<ast::StringValue*>;
	};

	struct Expression {
		static constexpr auto rule = lexy::dsl::p<Value> | lexy::dsl::p<String>;
		static constexpr auto value = lexy::forward<ast::Value*>;
	};

	struct AssignmentStatement {
		static constexpr auto rule = [] {
			auto right_brace = lexy::dsl::lit_c<'}'>;

			auto expression = lexy::dsl::p<Expression>;
			auto statement_list = lexy::dsl::recurse_branch<StatementListBlock>;

			auto rhs_recover = lexy::dsl::recover(expression, statement_list).limit(right_brace);
			auto rhs_try = lexy::dsl::try_(expression | statement_list, rhs_recover);

			auto identifier = dsl::p<Identifier> >> lexy::dsl::equal_sign + rhs_try;

			auto recover = lexy::dsl::recover(identifier).limit(right_brace);
			return lexy::dsl::try_(identifier, recover);
		}();

		static constexpr auto value = callback<ast::AssignStatement*>(
			[](detail::IsParseState auto& state, const char* pos, ast::IdentifierValue* name, ast::Value* initializer) -> ast::AssignStatement* {
				if (initializer == nullptr) return nullptr;
				return state.ast().template create<ast::AssignStatement>(pos, name, initializer);
			},
			[](detail::IsParseState auto& state, ast::Value*) {
				return nullptr;
			},
			[](detail::IsParseState auto& state) {
				return nullptr;
			});
	};

	struct StatementListBlock {
		static constexpr auto rule = [] {
			auto right_brace = lexy::dsl::lit_c<'}'>;
			auto comma = lexy::dsl::lit_c<','>;

			auto assign_statement = lexy::dsl::recurse_branch<AssignmentStatement>;
			auto assign_try = lexy::dsl::try_(assign_statement);

			auto curly_bracket = dsl::curly_bracketed.opt_list(
				assign_try,
				lexy::dsl::trailing_sep(comma));

			return lexy::dsl::try_(curly_bracket, lexy::dsl::find(right_brace));
		}();

		static constexpr auto value =
			lexy::as_list<ast::AssignStatementList> >> construct_list<ast::ListValue>;
	};

	struct File {
		// Allow arbitrary spaces between individual tokens.
		static constexpr auto whitespace = ovdl::v2script::grammar::whitespace_specifier | comment_specifier;

		static constexpr auto rule = lexy::dsl::position + lexy::dsl::terminator(lexy::dsl::eof).opt_list(lexy::dsl::p<AssignmentStatement>);

		static constexpr auto value = lexy::as_list<ast::AssignStatementList> >> construct<ast::FileTree>;
	};
}