Say what???

.ruby.rails/
.ruby.rails.200603/
.ruby.rails.200604/
.ruby.rails.200605/
.ruby.rails.200606/
.ruby.rails.200607/
.ruby.rails.200608/
.ruby.rails.200609/
.ruby.rails.200610/
.ruby.rails.200611/
.ruby.talk/
.ruby.talk.200603/
.ruby.talk.200604/
.ruby.talk.200605/
.ruby.talk.200606/
.ruby.talk.200607/
.ruby.talk.200608/
.ruby.talk.200609/
.ruby.talk.200610/
.ruby.talk.200611/

#!/usr/bin/env ruby
# Author: Kelly McCauley
# Copyright 2007 Kelly McCauley
# Source: http://svn.drotner.org/repos/unix_tools/trunk/bin/mail_sort.rb
# License: version 0.1 is Public Domain

require 'rubygems'
require 'optparse'        # Parses commandline options
require 'tmail'           # Handles the email parsing
require 'date'            # Ruby's date library
require 'fileutils'       # File and directory manipulation libarary

$VERBOSE = true

@version = '0.1'
@debug = 0
@quiet = false

@days_ago = 30              # Default "Sort and archive mail up to @days_ago".
@src_mail_dir = nil         # Maildir to sort and archive.
@thread_heads = {}          # Maps a thread head's Message-ID to
                            # its associated archive directory.
@thread_head_index = nil    # Location of a saved version of @thread_heads
                            # from a previous run.
@total_orphans = 0          # Count of thread children that have no parents.
@total_emails = 0           # Total emails read.
@total_emails_archived = 0  # Total emails that were moved to an archive
                            # directory.


#
# Methods
#

# Prints out the given msgs and opts to STDERR and then exits
def error_exit(opts, *msgs)
  msgs.each {|m| $stderr.print m}
  $stderr.puts opts
  exit(1)
end


# Loads a saved @thread_heads from a previous run into memory.
def load_thread_head_index(index_file)
  if File.file?(index_file)
    File.open(index_file) do |file|
      file.each_line do |line|
        key, year, sum, mon = line.chomp.split(/\t/)
        @thread_heads[key.to_sym] = [year.to_sym, sum.to_i, mon.to_sym]
      end
    end
  end
end

# Dumps @thread_heads that are less than 365 days ago to a file.
#
# I didn't serialize it to YAML because I didn't want the extra processing
# overhead or memory consumption.  I didn't Marshal it since I wanted the
# saved file to be tied to the particular version of Marshal.
def dump_thread_head_index(index_file)
  File.open(index_file, 'w') do |file|
    @thread_heads.each do |key,value|
      next if value[1] < @th_index_cutoff_sum
      file << "#{key.to_s}\t#{value.map{|x| x.to_s}.join("\t")}\n"
      @th_index_dump_count += 1
    end
  end
end


# Adds the given email to the @thread_heads lookup table.
def add_thread_head(email)
  unless @thread_heads.key?(email['message-id'].id.to_sym)
    $stderr.puts "th subject: '#{email['subject'].to_s}'" if @debug > 2
    @thread_heads[email['message-id'].id.to_sym] = [
      email['date'].date.year.to_s.to_sym,
      (
        email['date'].date.year.to_s +
        sprintf('%02d', email['date'].date.mon) +
        sprintf('%02d', email['date'].date.day)
      ).to_i,
      sprintf('%02d', email['date'].date.mon).to_sym,
    ]
  end
end

# Creates the archive maildir
def create_archive_maildir(root_archive_dir)
  sub_dirs = []
  sub_dirs << File.join(root_archive_dir, 'cur')
  sub_dirs << File.join(root_archive_dir, 'new')
  sub_dirs << File.join(root_archive_dir, 'tmp')
  options = {}
  options[:noop] = true if @debug > 2
  options[:verbose] = true if @debug > 1

  sub_dirs.each do |dir|
    unless File.directory?(dir)
      FileUtils.mkdir_p(dir, options)
    end
  end
  return sub_dirs
end


# Archives the given file to the give archive directory
def archive_email(root_archive_dir, filename)
  archive_dir = create_archive_maildir(root_archive_dir).shift
  options = {}
  options[:noop] = true if @debug > 2
  options[:verbose] = true if @debug > 1

  if @debug > 0
    FileUtils.cp(filename, archive_dir, options)
  else
    FileUtils.mv(filename, archive_dir)
  end

  @total_emails_archived += 1

end


# Archives the thread child email into the appropriate maildir
def archive_thread_child(thread_head, src_mail_dir, filename)
  $stderr.puts "tc #{filename}:  #{@thread_heads[thread_head][1]} <= #{@cutoff_sum}" if @debug > 2
  if (@thread_heads[thread_head][1] <= @cutoff_sum)
    $stderr.puts "tc filename: #{filename}" if @debug > 2
    root_archive_dir = "#{File.expand_path(src_mail_dir)}.#{@thread_heads[thread_head].first.to_s}#{@thread_heads[thread_head].last.to_s}"
    archive_email(root_archive_dir, filename)
  end
end


# Archives the thread head email into the appropriate maildir
def archive_thread_head(email, src_mail_dir, filename)
  # Determine this email's date sum.
  email_sum = (
    email['date'].date.year.to_s +
    sprintf('%02d', email['date'].date.mon) +
    sprintf('%02d', email['date'].date.day)
  ).to_i
  $stderr.puts "th #{filename}:  #{email_sum} <= #{@cutoff_sum}" if @debug > 2

  # Is the email before the cutoff date?
  if email_sum <= @cutoff_sum
    # Yes.
    $stderr.puts "th filename: #{filename}" if @debug > 2
    root_archive_dir = "#{File.expand_path(src_mail_dir)}.#{email['date'].date.year}#{sprintf('%02d', email['date'].date.mon)}"

    # Archive it.
    archive_email(root_archive_dir, filename)
  end
end


#
# Handle the commandline arguments
#

opts = OptionParser.new do |opts|
  opts.banner = "Usage: #{$0} [OPTIONS] MAILDIR"
  opts.separator("")
  opts.separator("OPTIONS")

  opts.on(
    '-D','--days-ago NUMBER',
    'Sort and archive mail up to --days-ago'
  ) do |days|
    @days_ago = days
  end

  opts.on(
    '-i','--thread-head-index FILE',
    'Specify the thread head index file'
  ) do |file|
    @thread_head_idx = file
  end

  opts.on_tail(
    '-q','--quiet',
    'Turns off all output including error output'
  ) do |q|
    @quiet = true
  end

  opts.on_tail(
    '-d','--debug',
    'Turns on debugging output'
  ) do |debug|
    @debug += 1
  end

  # help
  opts.on_tail(
    '-h', '--help', 'Shows this message'
  ) do ||
    error_exit(opts)
  end

  # version
  opts.on_tail(
    '-V', '--version',
    'Shows the version and copyright of db_diff'
  ) do ||
    error_exit(opts, "#{$0} version #{@version}\n")
  end

end

opts.parse!(ARGV)

# Make sure that the source Maildir is given and that the directory exists.
@src_mail_dir = ARGV.shift
error_exit(
  opts,
  "ERROR: failed to specify a MAILDIR\n"
) unless @src_mail_dir

error_exit(
  opts,
  "ERROR: MAILDIR does not exist: #{@src_mail_dir}\n"
) unless File.directory?(@src_mail_dir)


#
# Determine the cut-off dates.  Used in simple numerical comparison of dates.
#

# The cut-off date for determining if thread heads are targeted for archival.
@cutoff = Date.today - @days_ago
@cutoff_sum = (
  @cutoff.year.to_s +
  sprintf('%02d', @cutoff.mon) +
  sprintf('%02d', @cutoff.day)
).to_i

# The cut-off date for storing thread heads in @thread_heads.
thi = Date.today - 365
@th_index_cutoff_sum = (
  thi.year.to_s +
  sprintf('%02d', thi.mon) +
  sprintf('%02d', thi.day)
).to_i
@th_index_dump_count = 0

# Compose the location of the thread head index file
if @thread_head_index.nil?
  @thread_head_index = "#{File.expand_path(@src_mail_dir)}.mail_sort.idx"
end


# Pre-run debugging
if @debug > 0
  $stderr.puts "@debug: '#{@debug}'"
  $stderr.puts "@src_mail_dir: '#{@src_mail_dir}'"
  $stderr.puts "@thread_head_index: '#{@thread_head_index}'"
  $stderr.puts "@days_ago: '#{@days_ago}'"
  $stderr.puts "@cutoff: '#{@cutoff.to_s}'"
  $stderr.puts "@cutoff_sum: '#{@cutoff_sum.to_s}'"
  $stderr.puts "@th_index_cutoff_sum: '#{@th_index_cutoff_sum}'"
end


#
# Do the run.
#

# Load the thread head index if it exists.
load_thread_head_index(@thread_head_index)

# The location of the Maildir's cur directory.
src_mail_dir_cur = File.join(File.expand_path(@src_mail_dir),'cur')

# Iterate through each file in the Maildir's cur directory.
Dir.foreach(src_mail_dir_cur) do |filename|
  # Skip . and ..
  next if filename == '.'
  next if filename == '..'

  filename = File.join(src_mail_dir_cur, filename)

  # Skip any directories.
  next unless File.file?(filename)

  $stderr.puts "filename: #{filename}" if @debug > 2

  # Parse the file into an email.
  email = TMail::Mail.parse(IO.read(filename))

  if email['references'].nil? && email['in-reply-to'].nil?
    # This email is a thread head

    if email['message-id'].id.nil?
      # This email is a malformed email.
      $stderr.puts "No message-id for #{filename}" unless @quiet

    else
      # Add this email as a thread head.
      add_thread_head(email)

      # Archive this email.
      archive_thread_head(email, @src_mail_dir, filename)

    end

  else
    # This email is a thread child
    thread_head = nil

    # Determine the thread's head (Simple case first since it is the most
    # common)
    if !email['references'].nil? && !email['references'].ids.empty?
      # This email as a References header and it is not empty
      thread_head = email['references'].ids.first.to_sym

    elsif !email['in-reply-to'].nil? && !email['in-reply-to'].empty?
      # This email only has a In-Reply-To header which is not empty
      thread_head = email['in-reply-to'].to_s.to_sym

    end

    # Lookup the thread head in @thread_heads.
    if @thread_heads.key?(thread_head)
      # Found it, so archive this email in the thread head's archive directory.
      archive_thread_child(thread_head, @src_mail_dir, filename)

    else
      # Possibly an orphaned child.  See if any of its other references are
      # known thread heads.
      thread_head = nil

      if email['references'].nil? && !email['in-reply-to'].empty?
        # No References header so use the In-Reply-To header.
        ref = email['in-reply-to'].to_s.to_sym
        thread_head = ref if @thread_heads.key?(ref)

      elsif !email['references'].nil? && !email['references'].empty?
        # Use References header.  Iterate through each of the references and
        # use the first that matches as the thread's head.
        email['references'].ids.each do |ref|
          ref = ref.to_s.to_sym
          if @thread_heads.key?(ref)
            thread_head = ref
            break
          end
        end

      end

      # Do we now have the thread's head?
      if thread_head
        # Yes, so archive this email in the thread head's archive directory.
        archive_thread_child(thread_head, @src_mail_dir, filename)

      else
        # No.  We have an orphan.
        $stderr.puts "th orphan" if @debug > 2
        @total_orphans += 1

        # Archive it as a thread head.
        add_thread_head(email)
        archive_thread_head(email, @src_mail_dir, filename)

      end

    end

  end

  @total_emails += 1

end

# The run is done, so save @thread_heads.
dump_thread_head_index(@thread_head_index)

# Post-run debugging.
if @debug > 0
  $stderr.puts "@thread_heads.length: #{@thread_heads.length}"
  $stderr.puts "@total_orphans: #{@total_orphans}"
  $stderr.puts "@total_emails: #{@total_emails}"
  $stderr.puts "@total_emails_archived: #{@total_emails_archived}"
  $stderr.puts "@th_index_dump_count: #{@th_index_dump_count}"
end

a = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

b = a.clone                 #=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
b.reject! {true}            #=> []
b                           #=> []

b = a.clone                 #=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
b.reject! {false}           #=> nil
b                           #=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

b = a.clone                 #=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
b.reject! {|n| n == 3}      #=> [1, 2, 4, 5, 6, 7, 8, 9, 10]
b                           #=> [1, 2, 4, 5, 6, 7, 8, 9, 10]

b = a.clone                 #=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
b.reject! {|n| n % 2 == 0}  #=> [1, 3, 5, 7, 9]
b                           #=> [1, 3, 5, 7, 9]

a = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

a.reject {|n| nil}                        #=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
a.reject {|n| false}                      #=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
a.reject {|n| true}                       #=> []
a.reject {|n| ''}                         #=> []
a.reject {|n| 0}                          #=> []

a.reject {|n| n == 3}                     #=> [1, 2, 4, 5, 6, 7, 8, 9, 10]
a.reject {|n| n % 2 == 0 }                            #=> [1, 3, 5, 7, 9]
a.reject {|n| true if (n % 3 == 0) || (n % 5 == 0) }  #=> [1, 2, 4, 7, 8]

a = ["a", "b", "c", "d", "e", "f"]

a.last        #=> "f"
[].last       #=> nil

a.last(0)     #=> []
a.last(1)     #=> ["f"]
a.last(4)     #=> ["c", "d", "e", "f"]
a.last(99)    #=> ["a", "b", "c", "d", "e", "f"]
[].last(10)   #=> []

a = ["a", "b", "c", "d", "e", "f"]

a.first           #=> "a"
[].first          #=> nil

a.first(0)        #=> []
a.first(1)        #=> ["a"]
a.first(99)       #=> ["a", "b", "c", "d", "e", "f"]
[].first(10)      #=> []