#include <pslang/ast/print.hpp>
#include <pslang/ast/statement.hpp>
#include <pslang/ast/type_visitor.hpp>
#include <pslang/ast/expression_visitor.hpp>
#include <pslang/ast/statement_visitor.hpp>
#include <pslang/types/type_visitor.hpp>
#include <pslang/types/type.hpp>

#include <iomanip>

namespace pslang::ast
{

	namespace
	{

		print_options as_child(print_options options)
		{
			options.indent_level += 1;
			return options;
		}

		void put_indent(std::ostream & out, print_options const & options)
		{
			for (std::size_t i = 0; i < options.indent_level; ++i)
				out << options.indent_string;
		}

		struct raw_type_print_visitor
			: types::const_visitor<raw_type_print_visitor>
		{
			std::ostream & out;

			using const_visitor::apply;

			void apply(types::unit_type const & type)
			{
				out << "unit";
			}

			void apply(types::bool_type const &)
			{
				out << "bool";
			}

			void apply(types::i8_type const &)
			{
				out << "i8";
			}

			void apply(types::u8_type const &)
			{
				out << "u8";
			}

			void apply(types::i16_type const &)
			{
				out << "i16";
			}

			void apply(types::u16_type const &)
			{
				out << "u16";
			}

			void apply(types::i32_type const &)
			{
				out << "i32";
			}

			void apply(types::u32_type const &)
			{
				out << "u32";
			}

			void apply(types::i64_type const &)
			{
				out << "i64";
			}

			void apply(types::u64_type const &)
			{
				out << "u64";
			}

			void apply(types::f16_type const &)
			{
				out << "f16";
			}

			void apply(types::f32_type const &)
			{
				out << "f32";
			}

			void apply(types::f64_type const &)
			{
				out << "f64";
			}

			void apply(types::array_type const & type)
			{
				apply(*type.element_type);
				out << "[" << type.size << "]";
			}

			void apply(types::function_type const & type)
			{
				if (type.arguments.size() == 1 && !is_function_type(*type.arguments[0]))
				{
					apply(*type.arguments.front());
					out << " -> ";
					apply(*type.result);
					return;
				}

				out << '(';
				bool first = true;
				for (auto const & argument : type.arguments)
				{
					if (!first) out << ", ";
					first = false;
					apply(*argument);
				}
				out << ") -> ";
				apply(*type.result);
			}

			void apply(types::struct_type const & type)
			{
				out << type.node->name;
			}

			void apply(types::pointer_type const & type)
			{
				apply(*type.referenced_type);
				if (type.is_mutable)
					out << " mut";
				out << "*";
			}
		};

		struct type_print_visitor
			: const_type_visitor<type_print_visitor>
		{
			std::ostream & out;

			using const_type_visitor::apply;

			void apply(types::unit_type const &)
			{
				out << "unit";
			}

			template <typename T>
			void apply(types::primitive_type_base<T> const & type)
			{
				print(out, types::type{types::primitive_type{type}});
			}

			void apply(array_type const & type)
			{
				apply(*type.element_type);
				out << "[" << type.size << "]";
			}

			void apply(function_type const & type)
			{
				if (type.arguments.size() == 1 && !std::get_if<function_type>(type.arguments[0].get()))
				{
					apply(*type.arguments.front());
					out << " -> ";
					apply(*type.result);
					return;
				}

				out << '(';
				bool first = true;
				for (auto const & argument : type.arguments)
				{
					if (!first) out << ", ";
					first = false;
					apply(*argument);
				}
				out << ") -> ";
				apply(*type.result);
			}

			void apply(pointer_type const & type)
			{
				apply(*type.referenced_type);
				if (type.is_mutable)
					out << " mut";
				out << "*";
			}

			void apply(type_identifier const & type)
			{
				out << type.name;
			}
		};

		struct expression_print_visitor
			: const_expression_visitor<expression_print_visitor>
		{
			std::ostream & out;
			print_options options;

			using const_expression_visitor::apply;

			template <typename Node>
			void child(Node const & node)
			{
				++options.indent_level;
				apply(node);
				--options.indent_level;
			}

			void apply(bool_literal const & node)
			{
				put_indent(out, options);
				out << "bool literal { value = " << (node.value ? "true" : "false") << " }\n";
			}

			void apply(i8_literal const & node)
			{
				put_indent(out, options);
				out << "i8 literal { value = " << (std::int32_t)node.value << " }\n";
			}

			void apply(u8_literal const & node)
			{
				put_indent(out, options);
				out << "u8 literal { value = " << (std::uint32_t)node.value << " }\n";
			}

			void apply(i16_literal const & node)
			{
				put_indent(out, options);
				out << "i16 literal { value = " << node.value << " }\n";
			}

			void apply(u16_literal const & node)
			{
				put_indent(out, options);
				out << "u16 literal { value = " << node.value << " }\n";
			}

			void apply(i32_literal const & node)
			{
				put_indent(out, options);
				out << "i32 literal { value = " << node.value << " }\n";
			}

			void apply(u32_literal const & node)
			{
				put_indent(out, options);
				out << "u32 literal { value = " << node.value << " }\n";
			}

			void apply(i64_literal const & node)
			{
				put_indent(out, options);
				out << "i64 literal { value = " << node.value << " }\n";
			}

			void apply(u64_literal const & node)
			{
				put_indent(out, options);
				out << "u64 literal { value = " << node.value << " }\n";
			}

			void apply(f16_literal const & node)
			{
				put_indent(out, options);
				out << "f32 literal { value = " << std::setprecision(3) << node.value.repr << " }\n";
			}

			void apply(f32_literal const & node)
			{
				put_indent(out, options);
				out << "f32 literal { value = " << std::setprecision(7) << node.value << " }\n";
			}

			void apply(f64_literal const & node)
			{
				put_indent(out, options);
				out << "f64 literal { value = " << std::setprecision(15) << node.value << " }\n";
			}

			void apply(identifier const & node)
			{
				put_indent(out, options);
				out << "identifier { name = \"" << node.name << "\" }\n";
			}

			void apply(unary_operation const & node)
			{
				put_indent(out, options);
				out << node.type << '\n';
				child(*node.arg1);
			}

			void apply(binary_operation const & node)
			{
				put_indent(out, options);
				out << node.type << '\n';
				child(*node.arg1);
				child(*node.arg2);
			}

			void apply(cast_operation const & node)
			{
				put_indent(out, options);
				out << "cast as ";
				print(out, *node.type);
				out << '\n';
				child(*node.expression);
			}

			void apply(function_call const & node)
			{
				put_indent(out, options);
				if (node.function)
				{
					out << "call\n";
					child(*node.function);
				}
				if (node.type)
				{
					out << "constructor { type = ";
					print(out, *node.type);
					out << " }\n";
				}
				for (auto const & argument : node.arguments)
					child(*argument);
			}

			void apply(array const & node)
			{
				put_indent(out, options);
				out << "array\n";
				for (auto const & element : node.elements)
					child(*element);
			}

			void apply(array_access const & node)
			{
				put_indent(out, options);
				out << "array access\n";
				child(*node.array);
				child(*node.index);
			}

			void apply(field_access const & node)
			{
				put_indent(out, options);
				out << "field access { name = \"" << node.field_name << "\" }\n";
				child(*node.object);
			}

			void apply(if_expression const & node)
			{
				put_indent(out, options);
				out << "if\n";
				child(*node.condition);
				child(*node.if_true);
				child(*node.if_false);
			}

			void apply(sizeof_operator const & node)
			{
				put_indent(out, options);
				if (node.expression)
				{
					out << "sizeof\n";
					child(*node.expression);
				}
				else
				{
					out << "sizeof ";
					print(out, *node.type);
					out << "\n";
				}
			}

			void apply(alignof_operator const & node)
			{
				put_indent(out, options);
				if (node.expression)
				{
					out << "alignof\n";
					child(*node.expression);
				}
				else
				{
					out << "sizeof ";
					print(out, *node.type);
					out << "\n";
				}
			}
		};

		struct statement_print_visitor
			: const_statement_visitor<statement_print_visitor>
		{
			std::ostream & out;
			print_options options;

			using const_statement_visitor::apply;

			template <typename Node>
			void child(Node const & node)
			{
				++options.indent_level;
				apply(node);
				--options.indent_level;
			}

			void apply(expression_ptr const & node)
			{
				print(out, *node, options);
			}

			void apply(assignment const & node)
			{
				put_indent(out, options);
				out << "assignment\n";
				child(node.lhs);
				child(node.rhs);
			}

			void apply(variable_declaration const & node)
			{
				put_indent(out, options);
				out << "variable declaration { category = " << node.category << ", name = \"" << node.name << "\"";
				if (node.type)
				{
					out << ", type = ";
					print(out, *node.type);
				}
				out << " }\n";
				child(node.initializer);
			}

			void apply(if_chain const & node)
			{
				put_indent(out, options);
				out << "if chain\n";
				++options.indent_level;
				for (auto const & block : node.blocks)
				{
					put_indent(out, options);
					out << "condition\n";
					if (block.condition)
						child(block.condition);
					else
					{
						put_indent(out, as_child(options));
						out << "(none)\n";
					}

					put_indent(out, options);
					out << "body\n";
					child(*block.statements);
				}
				--options.indent_level;
			}

			void apply(while_block const & node)
			{
				put_indent(out, options);
				out << "while\n";
				child(node.condition);
				child(*node.statements);
			}

			void apply(break_statement const & node)
			{
				put_indent(out, options);
				out << "break\n";
			}

			void apply(continue_statement const & node)
			{
				put_indent(out, options);
				out << "continue\n";
			}

			void apply(function_definition const & node)
			{
				put_indent(out, options);
				out << "function { name = \"" << node.name << "\", return type = ";
				print(out, *node.return_type);
				out << " }\n";
				++options.indent_level;
				for (auto const & arg : node.arguments)
				{
					put_indent(out, options);
					out << "argument { name = \"" << arg.name << "\", type = ";
					print(out, *arg.type);
					out << " }\n";
				}
				put_indent(out, options);
				out << "body\n";
				child(*node.statements);
				--options.indent_level;
			}

			void apply(foreign_function_declaration const & node)
			{
				put_indent(out, options);
				out << "foreign function { name = \"" << node.name << "\", return type = ";
				print(out, *node.return_type);
				out << " }\n";
				++options.indent_level;
				for (auto const & arg : node.arguments)
				{
					put_indent(out, options);
					out << "argument { name = \"" << arg.name << "\", type = ";
					print(out, *arg.type);
					out << " }\n";
				}
				--options.indent_level;
			}

			void apply(return_statement const & node)
			{
				put_indent(out, options);
				out << "return\n";
				if (node.value)
					child(node.value);
			}

			void apply(struct_definition const & node)
			{
				put_indent(out, options);
				out << "struct { name = \"" << node.name << "\", size = " << node.layout.size << ", align = " << node.layout.alignment << " }\n";
				for (auto const & field : node.fields)
				{
					put_indent(out, as_child(options));
					out << "field { name = \"" << field.name << "\", type = ";
					print(out, *field.type);
					out << ", offset = " << field.layout.offset << " }\n";
				}
			}
		};

	}

	void print(std::ostream & out, types::type const & type)
	{
		raw_type_print_visitor{{}, out}.apply(type);
	}

	void print(std::ostream & out, type const & node)
	{
		type_print_visitor{{}, out}.apply(node);
	}

	void print(std::ostream & out, expression const & node, print_options const & options)
	{
		expression_print_visitor{{}, out, options}.apply(node);
	}

	void print(std::ostream & out, statement const & node, print_options const & options)
	{
		statement_print_visitor{{}, out, options}.apply(node);
	}

	void print(std::ostream & out, statement_list const & node, print_options const & options)
	{
		statement_print_visitor{{}, out, options}.apply(node);
	}

}