#!/usr/bin/ruby

# vim: set nosta noet ts=4 sw=4:

# A collection of messages for a specific archive thread.

#

#    thread = Ezmlm::List::Thread.new( list, 'acgcbmbmeapgpfckcdol' )

#    thread.subject         #=> "Help - navigate on interface?"

#    thread.first.date.to_s #=> "2017-05-07T14:55:05-07:00"

#

#---

class Ezmlm::List::Thread

	include Enumerable

	### Instantiate a new thread of messages given

	### a +list+ and a +thread_id+.

	###

	def initialize( list, thread_id )

		raise ArgumentError, "Unknown list object." unless list.respond_to?( :listdir )

		raise ArgumentError, "Malformed Thread ID." unless thread_id =~ /^\w{20}$/

		raise "Archiving is not enabled." unless list.archived?

		@list     = list

		@id       = thread_id

		@subject  = nil

		@messages = nil

		self.load_thread

	end

	# The list object this message is stored in.

	attr_reader :list

	# The thread's identifier.

	attr_reader :id

	# The subject line of the thread.

	attr_reader :subject

	# An array of member messages.

	attr_reader :messages

	# An array of member authors.

	attr_reader :authors

	### Enumerable API:  Lazy load each message ID as a

	### Ezmlm::List::Message, yielding it to the block.

	###

	def each

		self.load_thread # refresh for any thread updates since object was created

		self.messages.each do |id|

			yield Ezmlm::List::Message.new( self.list, id )

		end

	end

	alias_method :each_message, :each

	### Lazy load each author ID as a Ezmlm::List::Author, yielding it

	### to the block.

	###

	def each_author

		self.load_thread # refresh for any thread updates since object was created

		self.authors.each do |id|

			yield Ezmlm::List::Author.new( self.list, id )

		end

	end

	#########

	protected

	#########

	### Parse the subject index into an array of Messages.

	###

	def load_thread

		@messages = []

		@authors  = []

		path = self.thread_path

		raise "Unknown thread: %p" % [ self.id ] unless path.exist?

		path.open( 'r', encoding: Encoding::ISO8859_1 ) do |fh|

			fh.each_line.with_index do |line, i|

				if i.zero?

					@subject = line.match( /^\w+ (.+)/ )[1]

				else

					match = line.match( /^(\d+):\d+:(\w+) / ) or next

					self.messages << match[1].to_i

					self.authors  << match[2]

				end

			end

		end

	end

	### Return the path on disk for the thread index.

	###

	def thread_path

		prefix = self.id[ 0 ..  1 ]

		hash   = self.id[ 2 .. -1 ]

		return self.list.listdir + 'archive' + 'subjects' + prefix + hash

	end

end # class Ezmlm::List::Thread