# -*- coding: utf-8 -*-
#
# = Cinch Seen plugin
#
# == Configuration
# Add the following to your bot’s configure.do stanza:
#
#   config.plugins.options[Cinch::History] = {
#     :file => "/var/cache/seenlog.dat"
#   }
#
# [file]
#   Where to store the message log. This is a required
#   argument.
#
# == Author
# Marvin Gülker (Quintus)
#
# == License
# An seen info plugin for Cinch.
# Copyright © 2014 Marvin Gülker
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

class Cinch::Seen
  include Cinch::Plugin

  SeenInfo = Struct.new(:time, :nick, :message)

  match /seen (.*)/
  listen_to :connect, :method => :on_connect
  listen_to :channel, :method => :on_channel

  def on_connect(*)
    @filepath = config[:file] || raise("Missing required argument: :file")
    @file = File.open(@filepath, "a+")
    @file.seek(0, File::SEEK_END) # Work around Ruby bug https://bugs.ruby-lang.org/issues/10039
    @filemutex = Mutex.new

    at_exit{@file.close}
  end

  def on_channel(msg)
    return if msg.message.start_with?("\u0001") # ACTION

    @filemutex.synchronize do
      @file.puts("#{msg.time.to_i}\0#{msg.user.nick}\0#{msg.message.strip}")
    end
  end

  def execute(msg, nick)
    if nick == bot.nick
      msg.reply "Self-reference err err tilt BOOOOM"
      return
    end

    if info = find_last_message(nick)
      msg.reply("I have last seen #{nick} on #{info.time} saying: #{info.message}")
    else
      msg.reply("I have not yet seen #{nick} saying something.")
    end
  end

  private

  def find_last_message(nick)
    @filemutex.synchronize do
      @file.rewind
      @file.lines.reverse_each do |line|
        parts = line.split("\0")

        if parts[1] == nick
          return SeenInfo.new(Time.at(parts[0].to_i), parts[1], parts[2])
        end
      end

      @file.seek(0, File::SEEK_END)
    end

    nil
  end

end