require "pathname"

require "hbc/artifact/base"

module Hbc
  module Artifact
    class UninstallBase < Base
      # TODO: 500 is also hardcoded in cask/pkg.rb, but much of
      #       that logic is probably in the wrong location

      PATH_ARG_SLICE_SIZE = 500

      ORDERED_DIRECTIVES = [
                             :early_script,
                             :launchctl,
                             :quit,
                             :signal,
                             :login_item,
                             :kext,
                             :script,
                             :pkgutil,
                             :delete,
                             :trash,
                             :rmdir,
                           ].freeze

      # TODO: these methods were consolidated here from separate
      #       sources and should be refactored for consistency

      def self.expand_path_strings(path_strings)
        path_strings.map { |path_string|
          path_string.start_with?("~") ? Pathname.new(path_string).expand_path : Pathname.new(path_string)
        }
      end

      def self.remove_relative_path_strings(action, path_strings)
        relative = path_strings.map { |path_string|
          path_string if %r{/\.\.(?:/|\Z)}.match(path_string) || !%r{\A/}.match(path_string)
        }.compact
        relative.each do |path_string|
          opoo "Skipping #{action} for relative path #{path_string}"
        end
        path_strings - relative
      end

      def self.remove_undeletable_path_strings(action, path_strings)
        undeletable = path_strings.map { |path_string|
          path_string if MacOS.undeletable?(Pathname.new(path_string))
        }.compact
        undeletable.each do |path_string|
          opoo "Skipping #{action} for undeletable path #{path_string}"
        end
        path_strings - undeletable
      end

      def install_phase
        odebug "Nothing to do. The uninstall artifact has no install phase."
      end

      def uninstall_phase
        dispatch_uninstall_directives
      end

      def dispatch_uninstall_directives(expand_tilde = true)
        directives_set = @cask.artifacts[stanza]
        ohai "Running #{stanza} process for #{@cask}; your password may be necessary"

        directives_set.each do |directives|
          warn_for_unknown_directives(directives)
        end

        ORDERED_DIRECTIVES.each do |directive_sym|
          directives_set.select { |h| h.key?(directive_sym) }.each do |directives|
            args = [directives]
            args << expand_tilde if [:delete, :trash, :rmdir].include?(directive_sym)
            send("uninstall_#{directive_sym}", *args)
          end
        end
      end

      private

      def stanza
        self.class.artifact_dsl_key
      end

      def warn_for_unknown_directives(directives)
        unknown_keys = directives.keys - ORDERED_DIRECTIVES
        return if unknown_keys.empty?
        opoo %Q{Unknown arguments to #{stanza} -- #{unknown_keys.inspect}. Running "brew update; brew cleanup; brew cask cleanup" will likely fix it.}
      end

      # Preserve prior functionality of script which runs first. Should rarely be needed.
      # :early_script should not delete files, better defer that to :script.
      # If Cask writers never need :early_script it may be removed in the future.
      def uninstall_early_script(directives)
        uninstall_script(directives, directive_name: :early_script)
      end

      # :launchctl must come before :quit/:signal for cases where app would instantly re-launch
      def uninstall_launchctl(directives)
        Array(directives[:launchctl]).each do |service|
          ohai "Removing launchctl service #{service}"
          [false, true].each do |with_sudo|
            plist_status = @command.run("/bin/launchctl", args: ["list", service], sudo: with_sudo, print_stderr: false).stdout
            if plist_status =~ %r{^\{}
              @command.run!("/bin/launchctl", args: ["remove", service], sudo: with_sudo)
              sleep 1
            end
            paths = ["/Library/LaunchAgents/#{service}.plist",
                     "/Library/LaunchDaemons/#{service}.plist"]
            paths.each { |elt| elt.prepend(ENV["HOME"]) } unless with_sudo
            paths = paths.map { |elt| Pathname(elt) }.select(&:exist?)
            paths.each do |path|
              @command.run!("/bin/rm", args: ["-f", "--", path], sudo: with_sudo)
            end
            # undocumented and untested: pass a path to uninstall :launchctl
            next unless Pathname(service).exist?
            @command.run!("/bin/launchctl", args: ["unload", "-w", "--", service], sudo: with_sudo)
            @command.run!("/bin/rm",        args: ["-f", "--", service], sudo: with_sudo)
            sleep 1
          end
        end
      end

      # :quit/:signal must come before :kext so the kext will not be in use by a running process
      def uninstall_quit(directives)
        Array(directives[:quit]).each do |id|
          ohai "Quitting application ID #{id}"
          num_running = count_running_processes(id)
          next unless num_running > 0
          @command.run!("/usr/bin/osascript", args: ["-e", %Q{tell application id "#{id}" to quit}], sudo: true)
          sleep 3
        end
      end

      # :signal should come after :quit so it can be used as a backup when :quit fails
      def uninstall_signal(directives)
        Array(directives[:signal]).flatten.each_slice(2) do |pair|
          raise CaskInvalidError.new(@cask, "Each #{stanza} :signal must have 2 elements.") unless pair.length == 2
          signal, id = pair
          ohai "Signalling '#{signal}' to application ID '#{id}'"
          pids = get_unix_pids(id)
          next unless pids.any?
          # Note that unlike :quit, signals are sent from the current user (not
          # upgraded to the superuser).  This is a todo item for the future, but
          # there should be some additional thought/safety checks about that, as a
          # misapplied "kill" by root could bring down the system. The fact that we
          # learned the pid from AppleScript is already some degree of protection,
          # though indirect.
          odebug "Unix ids are #{pids.inspect} for processes with bundle identifier #{id}"
          Process.kill(signal, *pids)
          sleep 3
        end
      end

      def count_running_processes(bundle_id)
        @command.run!("/usr/bin/osascript",
                      args: ["-e", %Q{tell application "System Events" to count processes whose bundle identifier is "#{bundle_id}"}],
                      sudo: true).stdout.to_i
      end

      def get_unix_pids(bundle_id)
        pid_string = @command.run!("/usr/bin/osascript",
                                   args: ["-e", %Q{tell application "System Events" to get the unix id of every process whose bundle identifier is "#{bundle_id}"}],
                                   sudo: true).stdout.chomp
        return [] unless pid_string =~ %r{\A\d+(?:\s*,\s*\d+)*\Z} # sanity check
        pid_string.split(%r{\s*,\s*}).map(&:strip).map(&:to_i)
      end

      def uninstall_login_item(directives)
        Array(directives[:login_item]).each do |name|
          ohai "Removing login item #{name}"
          @command.run!("/usr/bin/osascript",
                        args: ["-e", %Q{tell application "System Events" to delete every login item whose name is "#{name}"}],
                        sudo: false)
          sleep 1
        end
      end

      # :kext should be unloaded before attempting to delete the relevant file
      def uninstall_kext(directives)
        Array(directives[:kext]).each do |kext|
          ohai "Unloading kernel extension #{kext}"
          is_loaded = @command.run!("/usr/sbin/kextstat", args: ["-l", "-b", kext], sudo: true).stdout
          if is_loaded.length > 1
            @command.run!("/sbin/kextunload", args: ["-b", kext], sudo: true)
            sleep 1
          end
        end
      end

      # :script must come before :pkgutil, :delete, or :trash so that the script file is not already deleted
      def uninstall_script(directives, directive_name: :script)
        executable, script_arguments = self.class.read_script_arguments(directives,
                                                                        "uninstall",
                                                                        { must_succeed: true, sudo: true },
                                                                        { print_stdout: true },
                                                                        directive_name)
        ohai "Running uninstall script #{executable}"
        raise CaskInvalidError.new(@cask, "#{stanza} :#{directive_name} without :executable.") if executable.nil?
        executable_path = @cask.staged_path.join(executable)
        @command.run("/bin/chmod", args: ["--", "+x", executable_path]) if File.exist?(executable_path)
        @command.run(executable_path, script_arguments)
        sleep 1
      end

      def uninstall_pkgutil(directives)
        ohai "Removing files from pkgutil Bill-of-Materials"
        Array(directives[:pkgutil]).each do |regexp|
          pkgs = Hbc::Pkg.all_matching(regexp, @command)
          pkgs.each(&:uninstall)
        end
      end

      def uninstall_delete(directives, expand_tilde = true)
        Array(directives[:delete]).concat(Array(directives[:trash])).flatten.each_slice(PATH_ARG_SLICE_SIZE) do |path_slice|
          ohai "Removing files: #{path_slice.utf8_inspect}"
          path_slice = self.class.expand_path_strings(path_slice) if expand_tilde
          path_slice = self.class.remove_relative_path_strings(:delete, path_slice)
          path_slice = self.class.remove_undeletable_path_strings(:delete, path_slice)
          @command.run!("/bin/rm", args: path_slice.unshift("-rf", "--"), sudo: true)
        end
      end

      # :trash functionality is stubbed as a synonym for :delete
      # TODO: make :trash work differently, moving files to the Trash
      def uninstall_trash(directives, expand_tilde = true)
        uninstall_delete(directives, expand_tilde)
      end

      def uninstall_rmdir(directives, expand_tilde = true)
        Array(directives[:rmdir]).flatten.each do |directory|
          directory = self.class.expand_path_strings([directory]).first if expand_tilde
          directory = self.class.remove_relative_path_strings(:rmdir, [directory]).first
          directory = self.class.remove_undeletable_path_strings(:rmdir, [directory]).first
          next if directory.to_s.empty?
          ohai "Removing directory if empty: #{directory.to_s.utf8_inspect}"
          directory = Pathname.new(directory)
          next unless directory.exist?
          @command.run!("/bin/rm",
                        args:         ["-f", "--", directory.join(".DS_Store")],
                        sudo:         true,
                        print_stderr: false)
          @command.run("/bin/rmdir",
                       args:         ["--", directory],
                       sudo:         true,
                       print_stderr: false)
        end
      end
    end
  end
end