# encoding: utf-8
# frozen_string_literal: true
# rubocop:disable Metrics/CyclomaticComplexity

require "carbon/compiler/parser/statements/if"
require "carbon/compiler/parser/statements/match"
require "carbon/compiler/parser/statements/try"

module Carbon
  module Compiler
    class Parser
      # Parses statements.
      module Statements
        include If
        include Match
        include Try

      protected

        def parse_statement
          case peek.type
          when :if     then parse_statement_if
          when :match  then parse_statement_match
          when :try    then parse_statement_try
          when :for    then parse_statement_for
          when :return then parse_statement_return
          when :while  then parse_statement_while
          when :let    then parse_statement_let
          when :do     then parse_function_body
          else
            expr = parse_expression
            expect :";"
            expr
          end
        end

        def parse_statement_return
          expect :return
          expr = parse_expression unless peek? :";"
          expect :";"

          Node::Statement::Return.new([expr].compact)
        end

        def parse_statement_let
          expect :let
          name = parse_name
          expect :":"
          type = parse_type
          value =
            if peek? :"="
              expect :"="
              parse_expression
            end
          expect :";"

          Node::Statement::Let.new([name, type, value])
        end

        def parse_statement_while
          expect :while
          expect :"("
          condition = parse_expression
          expect :")"
          body = parse_statement

          Node::Statement::While.new([condition, body])
        end

        def parse_statement_for
          expect :for
          expect :"("
          initial = parse_expression
          expect :";"
          condition = parse_expression
          expect :";"
          increment = parse_expression
          expect :")"
          body = parse_statement

          Node::Statement::For.new([initial, condition, increment, body])
        end
      end
    end
  end
end