# frozen_string_literal: true

require "parser/current"
require "dependabot/file_updaters/ruby/bundler"

module Dependabot
  module FileUpdaters
    module Ruby
      class Bundler
        class GitSourceRemover
          attr_reader :dependency

          def initialize(dependency:)
            @dependency = dependency
          end

          def rewrite(content)
            buffer = Parser::Source::Buffer.new("(gemfile_content)")
            buffer.source = content
            ast = Parser::CurrentRuby.new.parse(buffer)

            Rewriter.new(dependency: dependency).rewrite(buffer, ast)
          end

          class Rewriter < Parser::TreeRewriter
            # TODO: Hack until Bundler 1.16.0 is available on Heroku
            GOOD_KEYS = %i(
              group groups path glob name require platform platforms type
              source install_if
            ).freeze

            attr_reader :dependency

            def initialize(dependency:)
              @dependency = dependency
            end

            def on_send(node)
              return unless declares_targeted_gem?(node)
              return unless node.children.last.type == :hash

              kwargs_node = node.children.last
              keys = kwargs_node.children.map do |hash_pair|
                key_from_hash_pair(hash_pair)
              end

              if keys.none? { |key| GOOD_KEYS.include?(key) }
                remove_all_kwargs(node)
              else
                remove_git_related_kwargs(kwargs_node)
              end
            end

            private

            def declares_targeted_gem?(node)
              return false unless node.children[1] == :gem

              node.children[2].children.first == dependency.name
            end

            def key_from_hash_pair(node)
              node.children.first.children.first.to_sym
            end

            def remove_all_kwargs(node)
              kwargs_node = node.children.last

              range_to_remove =
                kwargs_node.loc.expression.join(node.children[-2].loc.end.end)

              remove(range_to_remove)
            end

            def remove_git_related_kwargs(kwargs_node)
              good_key_index = nil
              hash_pairs = kwargs_node.children

              hash_pairs.each_with_index do |hash_pair, index|
                if GOOD_KEYS.include?(key_from_hash_pair(hash_pair))
                  good_key_index = index
                  next
                end

                range_to_remove =
                  if good_key_index.nil?
                    next_arg_start = hash_pairs[index + 1].loc.expression.begin
                    hash_pair.loc.expression.join(next_arg_start)
                  else
                    last_arg_end = hash_pairs[good_key_index].loc.expression.end
                    hash_pair.loc.expression.join(last_arg_end)
                  end

                remove(range_to_remove)
              end
            end
          end
        end
      end
    end
  end
end