--- /dev/null
+# frozen_string_literal: true
+
+require 'pronto'
+require 'shellwords'
+
+module Pronto
+ module Hlint
+ class Runner < Pronto::Runner
+ CONFIG_FILE = '.pronto_hlint.yml'.freeze
+ CONFIG_KEYS = %w[hlint_executable files_to_lint cmd_line_opts].freeze
+
+ attr_writer :hlint_executable, :cmd_line_opts
+
+ def hlint_executable
+ @hlint_executable || 'hlint'
+ end
+
+ def files_to_lint
+ @files_to_lint || /(\.hs)$/
+ end
+
+ def cmd_line_opts
+ @cmd_line_opts || ''
+ end
+
+ def files_to_lint=(regexp)
+ @files_to_lint = regexp.is_a?(Regexp) && regexp || Regexp.new(regexp)
+ end
+
+ def config_options
+ @config_options ||=
+ begin
+ config_file = File.join(repo_path, CONFIG_FILE)
+ File.exist?(config_file) && YAML.load_file(config_file) || {}
+ end
+ end
+
+ def read_config
+ config_options.each do |key, val|
+ next unless CONFIG_KEYS.include?(key.to_s)
+ send("#{key}=", val)
+ end
+ end
+
+ def run
+ return [] if !@patches || @patches.count.zero?
+
+ read_config
+
+ @patches
+ .select { |patch| patch.additions > 0 }
+ .select { |patch| hs_file?(patch.new_file_full_path) }
+ .map { |patch| inspect(patch) }
+ .flatten.compact
+ end
+
+ private
+
+ def repo_path
+ @repo_path ||= @patches.first.repo.path
+ end
+
+ def inspect(patch)
+ offences = run_hlint(patch)
+ offences
+ .map do |offence|
+ patch
+ .added_lines
+ .select { |line| (offence['startLine']..offence['endLine']).include?(line.new_lineno) }
+ .map { |line| new_message(offence, line) }
+ end
+ end
+
+ def new_message(offence, line)
+ path = line.patch.delta.new_file[:path]
+ level = hlint_severity_to_pronto_level(offence['severity']) || :warning
+
+ text = <<~EOF
+ #{offence['severity']} offence detected by Hlint. Hint is: `#{offence['hint']}`.
+
+ Consider changing the code from
+ ```
+ #{offence['from']}
+ ```
+ to
+ ```
+ #{offence['to']}
+ ```
+ EOF
+
+ Message.new(path, line, level, text, nil, self.class)
+ end
+
+ def hlint_severity_to_pronto_level(severity)
+ case severity
+ when "Error"
+ :error
+ when "Warning"
+ :warning
+ when "Suggestion"
+ :info
+ end
+ end
+
+ def hs_file?(path)
+ files_to_lint =~ path.to_s
+ end
+
+ def run_hlint(patch)
+ Dir.chdir(repo_path) do
+ JSON.parse `#{hlint_command_line(patch.new_file_full_path.to_s)}`
+ end
+ end
+
+ def hlint_command_line(path)
+ "#{hlint_executable} #{cmd_line_opts} #{Shellwords.escape(path)} --json"
+ end
+ end
+ end
+end