#!/usr/bin/env ruby
# Copyright (C) 2013-2015 all contributors <dtas-all@nongnu.org>
# License: GPLv3 or later (https://www.gnu.org/licenses/gpl-3.0.txt)
require 'optparse'
require 'dtas/edit_client'
require 'dtas/sigevent'
require 'dtas/watchable'
include DTAS::EditClient
c = client_socket
sinks = c.req('sink ls') || "(unknown)"
usage = "Usage: #{DTAS_PROGNAME} [OPTIONS] SINKNAME\n" \
        "available SINKNAME values: #{sinks}"
dry_run = verbose = false
watch = defined?(DTAS::Watchable)

OptionParser.new('', 24, '  ') do |op|
  op.banner = usage
  watch and
    op.on('-N', '--no-watch', 'disable inotify support') { watch = false }

  op.on('-n', '--dry-run', 'only print commands, do not run them') {
    dry_run = true
  }
  op.on('-V', '--verbose', 'print out commands sent to change the sink') {
    verbose = true
  }
  op.on('-h', '--help') { puts(op.to_s); exit }
  op.parse!(ARGV)
end

ARGV.size == 1 or abort usage
name = ARGV[0]

st_in = $stdin.stat

buf = c.req(%W(sink cat #{name}))
abort(buf) if buf =~ /\AERR/
orig = YAML.load(buf)

commit_update = lambda do |buf|
  sink = YAML.load(buf)
  cmd = %W(sink ed #{name})
  update_cmd_env(cmd, orig, sink)

  # both of these default to false
  %w(nonblock active).each do |field|
    cmd << "#{field}=#{sink[field] ? 'true' : 'false'}"
  end

  %w(prio).each do |field|
    value = sink[field] and cmd << "#{field}=#{value}"
  end

  %w(pipe_size).each { |field| cmd << "#{field}=#{sink[field]}" }

  # nil OK
  %w(command).each do |field|
    cmd << "#{field}=#{sink[field]}"
  end

  warn(Shellwords.join(cmd)) if verbose || dry_run
  c.req_ok(cmd) unless dry_run
  orig = sink
end

if st_in.file? || st_in.pipe?
  buf = $stdin.read
  commit_update.call(buf)
else
  include DTAS::SpawnFix
  tmp = tmpyaml
  tmp_path = tmp.path
  do_update = lambda { commit_update.call(File.read(tmp_path)) }
  tmp.write(buf << DTAS_DISCLAIMER)
  cmd = "#{editor} #{tmp_path}"

  sev = DTAS::Sigevent.new
  rset = [ sev ]
  if watch
    ino = DTAS::Watchable::InotifyReadableIter.new
    ino.watch_files(tmp_path, do_update)
    rset << ino
  end

  trap(:CHLD) { sev.signal }
  pid = spawn(cmd)
  begin
    r = IO.select(rset) or next
    r[0].each do |io|
      case io
      when sev
        _, status = Process.waitpid2(pid, Process::WNOHANG)
        status or next
        status.success? or abort "#{cmd} failed: #{status.inspect}"
        do_update.call
        exit
      when ino
        ino.readable_iter # calls do_update
      end
    end
  end while true
end