require 'etc'
require 'fileutils'
require 'json'

module InstanceAgent
  module Plugins
    module CodeDeployPlugin
      class InstallInstruction
        def self.generate_commands_from_file(file)
          name = File.basename(file.path)
          file = File.open(file.path, 'r')
          contents = file.read
          file.close
          if name =~ /^*-install.json/
            parse_install_commands(contents)
          elsif name =~ /^*-cleanup/
            parse_remove_commands(contents)
          end
        end

        def self.parse_install_commands(contents)
          instructions = JSON.parse(contents)['instructions']
          commands = []
          instructions.each do |mapping|
            case mapping['type']
            when "copy"
              commands << CopyCommand.new(mapping["source"], mapping["destination"])
            when "mkdir"
              commands << MakeDirectoryCommand.new(mapping["directory"])
            when "chmod"
              commands << ChangeModeCommand.new(mapping['file'], mapping['mode'])
            when "chown"
              commands << ChangeOwnerCommand.new(mapping['file'], mapping['owner'], mapping['group'])
            when "setfacl"
              commands << ChangeAclCommand.new(mapping['file'], InstanceAgent::Plugins::CodeDeployPlugin::ApplicationSpecification::AclInfo.new(mapping['acl']))
            when "semanage"
              if !mapping['context']['role'].nil?
                raise "The deployment failed because the application specification file specifies a role, but roles are not supported. Remove the role from the AppSpec file, and then try again."
              end
              commands << ChangeContextCommand.new(mapping['file'], InstanceAgent::Plugins::CodeDeployPlugin::ApplicationSpecification::ContextInfo.new(mapping['context']))
            else
              raise "Unknown command: #{mapping}"
            end
          end
          commands
        end

        def self.parse_remove_commands(contents)
          return [] if contents.empty?
          #remove the unfinished paths
          lines = contents.lines.to_a
          if lines.last[lines.last.length-1] != "\n"
            lines.pop
          end
          commands = []
          lines.each do |command|
            if command.start_with?("semanage\0")
              commands << RemoveContextCommand.new(command.split("\0",2)[1].strip)
            else
              commands << RemoveCommand.new(command.strip)
            end
          end
          commands.reverse
        end

        def self.generate_instructions()
          command_builder = CommandBuilder.new()
          yield(command_builder)
          command_builder
        end
      end

      class CommandBuilder
        attr_reader :command_array
        def initialize()
          @command_array = []
          @copy_targets = Hash.new
          @mkdir_targets = Set.new
          @permission_targets = Set.new
        end

        def copy(source, destination)
          destination = sanitize_dir_path(destination)
          log(:debug, "Copying #{source} to #{destination}")
          raise "The deployment failed because the application specification file specifies two source files named #{source} and #{@copy_targets[destination]} for the same destination (#{destination}). Remove one of the source file paths from the AppSpec file, and then try again." if @copy_targets.has_key?(destination)
          raise "The deployment failed because the application specification file calls for installing the file #{source}, but a file with that name already exists at the location (#{destination}). Update your AppSpec file or directory structure, and then try again." if @mkdir_targets.include?(destination)
          @command_array << CopyCommand.new(source, destination)
          @copy_targets[destination] = source
        end

        def mkdir(destination)
          destination = sanitize_dir_path(destination)
          log(:debug, "Making directory #{destination}")
          raise "The deployment failed because the application specification file includes an mkdir command more than once for the same destination path (#{destination}) from (#{@copy_targets[destination]}). Update the files section of the AppSpec file, and then try again." if @copy_targets.has_key?(destination)
          @command_array << MakeDirectoryCommand.new(destination) unless @mkdir_targets.include?(destination)
          @mkdir_targets.add(destination)
        end

        def set_permissions(object, permission)
          object = sanitize_dir_path(object)
          log(:debug, "Setting permissions on #{object}")
          raise "The deployment failed because the permissions setting for (#{object}) is specified more than once in the application specification file. Update the files section of the AppSpec file, and then try again." if @permission_targets.include?(object)
          @permission_targets.add(object)

          if !permission.mode.nil?
            log(:debug, "Setting mode on #{object}")
            @command_array << ChangeModeCommand.new(object, permission.mode.mode)
          end

          if !permission.acls.nil?
            log(:debug, "Setting acl on #{object}")
            @command_array << ChangeAclCommand.new(object, permission.acls)
          end

          if !permission.context.nil?
            log(:debug, "Setting context on #{object}")
            @command_array << ChangeContextCommand.new(object, permission.context)
          end

          if !permission.owner.nil? || !permission.group.nil?
            log(:debug, "Setting ownership of #{object}")
            @command_array << ChangeOwnerCommand.new(object, permission.owner, permission.group)
          end
        end

        def copying_file?(file)
          file = sanitize_dir_path(file)
          log(:debug, "Checking for #{file} in #{@copy_targets.keys.inspect}")
          @copy_targets.has_key?(file)
        end

        def making_directory?(dir)
          dir = sanitize_dir_path(dir)
          log(:debug, "Checking for #{dir} in #{@mkdir_targets.inspect}")
          @mkdir_targets.include?(dir)
        end

        def find_matches(permission)
          log(:debug, "Finding matches for #{permission.object}")
          matches = []
          if permission.type.include?("file")
            @copy_targets.keys.each do |object|
              log(:debug, "Checking #{object}")
              if (permission.matches_pattern?(object) && !permission.matches_except?(object))
                log(:debug, "Found match #{object}")
                permission.validate_file_acl(object)
                matches << object
              end
            end
          end
          if permission.type.include?("directory")
            @mkdir_targets.each do |object|
              log(:debug, "Checking #{object}")
              if (permission.matches_pattern?(object) && !permission.matches_except?(object))
                log(:debug, "Found match #{object}")
                matches << object
              end
            end
          end
          matches
        end

        def to_json
          command_json = @command_array.map(&:to_h)
          {:instructions => command_json}.to_json
        end

        def each(&block)
          @command_array.each(&block)
        end

        # Clean up explicitly since these can grow to tens of MBs if the deployment archive is large.
        def cleanup()
          @command_array.clear
          @command_array = nil
          @copy_targets.clear
          @copy_targets = nil
          @mkdir_targets.clear
          @mkdir_targets = nil
          @permission_targets.clear
          @permission_targets = nil
        end

        private
        def sanitize_dir_path(path)
          File.expand_path(path)
        end

        private
        def description
          self.class.to_s
        end

        private
        def log(severity, message)
          raise ArgumentError, "Unknown severity #{severity.inspect}" unless InstanceAgent::Log::SEVERITIES.include?(severity.to_s)
          InstanceAgent::Log.send(severity.to_sym, "#{description}: #{message}")
        end
      end

      class RemoveCommand
        def initialize(location)
          @file_path = location
        end

        def execute
          #If the file doesn't exist the command is ignored
          if File.symlink?(@file_path)
            FileUtils.rm(@file_path)
          elsif File.exist?(@file_path)
            if File.directory?(@file_path)
              begin
                FileUtils.rmdir(@file_path)
              rescue Errno::ENOTEMPTY
              end
            else
              FileUtils.rm(@file_path)
            end
          end
        end
      end

      class CopyCommand
        attr_reader :destination, :source
        def initialize(source, destination)
          @source = source
          @destination = destination
        end

        def execute(cleanup_file)
          # NO need to check if file already exists in here, because if that's the case,
          # the CopyCommand entry should not even be created by Installer
          cleanup_file.puts(@destination)
          if File.symlink?(@source)
            FileUtils.symlink(File.readlink(@source), @destination)
          else
            FileUtils.copy(@source, @destination, :preserve => true)
          end
        end

        def to_h
          {:type => :copy, :source => @source, :destination => @destination}
        end
      end

      class MakeDirectoryCommand
        def initialize(destination)
          @directory = destination
        end

        def execute(cleanup_file)
          # NO need to check if file already exists in here, because if that's the case,
          # the MakeDirectoryCommand entry should not even be created by Installer
          FileUtils.mkdir(@directory)
          cleanup_file.puts(@directory)
        end

        def to_h
          {:type => :mkdir, :directory => @directory}
        end
      end

      class ChangeModeCommand
        def initialize(object, mode)
          @object = object
          @mode = mode
        end

        def execute(cleanup_file)
          File.chmod(@mode.to_i(8), @object)
        end

        def to_h
          {:type => :chmod, :mode => @mode, :file => @object}
        end
      end

      class ChangeAclCommand
        def initialize(object, acl)
          @object = object
          @acl = acl
        end

        def execute(cleanup_file)
          begin
            get_full_acl
            acl = @acl.get_acl.join(",")
            if !system("setfacl --set #{acl} #{@object}")
              raise "The deployment failed because of a problem with the acls permission settings in the application specification file for this object: #{@object}. Failed command: setfacl --set #{acl} #{@object}. Exit code: #{$?}"
            end
          ensure
            clear_full_acl
          end
        end

        def clear_full_acl
          @acl.clear_additional
        end

        def get_full_acl()
          perm = "%o" % File.stat(@object).mode
          perm = perm[-3,3]
          @acl.add_ace(":#{perm[0]}")
          @acl.add_ace("g::#{perm[1]}")
          @acl.add_ace("o::#{perm[2]}")
          if @acl.has_base_named? && !@acl.has_base_mask?
            @acl.add_ace("m::#{perm[1]}")
          end
          if @acl.has_default?
            if !@acl.has_default_user?
              @acl.add_ace("d::#{perm[0]}")
            end
            if !@acl.has_default_group?
              @acl.add_ace("d:g::#{perm[1]}")
            end
            if !@acl.has_default_other?
              @acl.add_ace("d:o:#{perm[2]}")
            end
            if @acl.has_default_named? && !@acl.has_default_mask?
              @acl.add_ace(@acl.get_default_group_ace.sub("group:","mask"))
            end
          end
        end

        def to_h
          {:type => :setfacl, :acl => @acl.get_acl, :file => @object}
        end
      end

      class ChangeOwnerCommand
        def initialize(object, owner, group)
          @object = object
          @owner = owner
          @group = group
        end

        def execute(cleanup_file)
          ownerid = Etc.getpwnam(@owner).uid if @owner
          groupid = Etc.getgrnam(@group).gid if @group
          File.chown(ownerid, groupid, @object)
        end

        def to_h
          {:type => :chown, :owner => @owner, :group => @group, :file => @object}
        end
      end

      class ChangeContextCommand
        def initialize(object, context)
          @object = object
          @context = context
        end

        def execute(cleanup_file)
          if !@context.role.nil?
            raise "The deployment failed because the application specification file specifies a role, but roles are not supported. Remove the role from the AppSpec file, and then try again."
          end
          args = "-t #{@context.type}"
          if (!@context.user.nil?)
            args = "-s #{@context.user} " + args
          end
          if (!@context.range.nil?)
            args = args + " -r #{@context.range.get_range}"
          end

          object = File.realpath(@object)
          if !system("semanage fcontext -a #{args} #{object}")
            raise "The deployment failed because the application specification file contains an error in the settings for the context parameter. Update the permissions section of the AppSpec file, and then try again. Failed command: semanage fcontext -a #{args} #{object}. Exit code: #{$?}"
          end
          if !system("restorecon -v #{object}")
            raise "The deployment failed because the application specification file contains an error in the settings for the context parameter. Update the permissions section of the AppSpec file, and then try again. Failed command: restorecon -v #{object}. Exit code: #{$?}"
          end
          cleanup_file.puts("semanage\0#{object}")
        end

        def to_h
          {:type => :semanage, :context => {:user => @context.user, :role => @context.role, :type => @context.type, :range => @context.range.get_range}, :file => @object}
        end
      end

      class RemoveContextCommand
        def initialize(object)
          @object = object
        end

        def execute
          system("semanage fcontext -d #{@object}")
        end
      end
    end
  end
end