From 5753c04bcd0cb55c892b623c6b7163dd3d9da704 Mon Sep 17 00:00:00 2001
From: Jon Michael Aanes <jonjmaa@gmail.com>
Date: Fri, 8 Jun 2018 13:37:31 +0200
Subject: [PATCH] A little restructure and implementation of better CTRL+C
 handling.

---
 main.lua | 101 +++++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 83 insertions(+), 18 deletions(-)

diff --git a/main.lua b/main.lua
index 2f05a3d..e23697d 100644
--- a/main.lua
+++ b/main.lua
@@ -1,4 +1,7 @@
 
+-- TODO: Invite to bogus channels
+-- TODO: Make text randomly colored
+
 -- Constants
 
 math.randomseed(os.time())
@@ -14,15 +17,33 @@ end
 if CONFIG.LUA_EXTRA_PATH  then  package.path  = package.path  .. CONFIG.LUA_EXTRA_PATH   end
 if CONFIG.LUA_EXTRA_CPATH then  package.cpath = package.cpath .. CONFIG.LUA_EXTRA_CPATH  end
 
+--------------------------------------------------------------------------------
+-- Constants
+
 local FARVEL_INTERVAL  = 90
 
--- TODO: Invite to bogus channels
+--------------------------------------------------------------------------------
+-- Make sure all required modules can be loaded
+
+local imlib = require 'imlib2'
+
+require 'socket'
+local https = require 'ssl.https'
+
+local json = require 'json'
+
+require 'irc.init'
+
+local sleep = require 'socket'.sleep
+
+local signal do
+    local a, b  =  pcall(require, 'posix.signal')
+    if a then  signal = b  end
+end
 
 --------------------------------------------------------------------------------
 -- Meme utils
 
-local imlib = require 'imlib2'
-
 for _, path in ipairs(CONFIG.IMGGEN_PATH_FONTS) do
     imlib.font.add_path(path)
 end
@@ -40,11 +61,6 @@ local function flatten_onto(target_img, other_img, x0, y0)
     return
 end
 
-require 'socket'
-local https = require 'ssl.https'
-
-local json = require 'json'
-
 local function search_clearbit_for_logo (topic)
     if not (type(topic) == 'string' and topic == topic:lower() and #topic > 0) then
         return nil, 'Bad topic: '..tostring(topic)
@@ -101,12 +117,6 @@ local function generate_bait_link()
     return 'https://dcav.pw/jbait'
 end
 
-require 'irc.init'
-
-local sleep = require 'socket'.sleep
-
---require 'errors' 'memebot' . enable_strict_globals()
-
 local function determine_required_font_size (font_name, text, width)
     local size_min, size_max  =  1, 50
     while true do
@@ -279,6 +289,20 @@ local FARVEL = {
     ['[Ss]es'] = {'ses selv', 'farvel'},
 }
 
+local ACTIVE_CHANNELS = {}
+
+local function join_channel (channel)
+    ACTIVE_CHANNELS[channel]  =  true
+    bot:join(channel)
+end
+
+local function leave_channel (channel)
+    if ACTIVE_CHANNELS[channel] then
+        ACTIVE_CHANNELS[channel]  =  nil
+        bot:part(channel)
+    end
+end
+
 local LAST_ACTIVE = os.time()
 local ACTIVE_PERIOD = 10
 
@@ -405,7 +429,7 @@ local function handle_message(bot, user, channel, message)
         if msg:match '%s*join%s+(#%a)' then
             local channel  =  msg:match '^%s*join%s+(#%a+)%s*$'
             bot:sendChat(channel, "Will do! I'll join "..tostring(channel))
-            bot:join(channel)
+            join_channel(channel)
         else
             bot:sendChat(channel, ERROR_MSG[math.random(#ERROR_MSG)])
         end
@@ -483,24 +507,65 @@ bot:hook('OnRaw', function (line)
     io.write(("           [RAW]:  %s\n"):format(line))
 end)
 
+local function send_to_all (fmt, ...)
+    local msg = fmt:format(...)
+    for channel in pairs(ACTIVE_CHANNELS) do
+        bot:sendChat(channel, msg)
+    end
+end
+
 --------------------------------------------------------------------------------
 -- Main run
 
+local BOT_FAREWELL = {
+    'Fuck, politiet fandt mig!',
+    'Håber I kunne lide mine memes, for nu får I ikke flere!',
+    'Farewell cruel world!',
+    'Jeg har fundet et vidunderligt bevis, men er for langt til den tid SIGINT giver mig.',
+    'Jeg dropper ud.',
+    'Jeg keder mig.'
+}
+
+local function shutdown_memebot ()
+    -- Leave channels
+    for channel in pairs(ACTIVE_CHANNELS) do
+        leave_channel(channel)
+    end
+    -- Leave IRC
+    bot:disconnect()
+end
+
 local function init_memebot ()
+    -- Connection to IRC
     bot:connect {
         host   = CONFIG.IRC_SERVER,
         port   = CONFIG.IRC_PORT,
         secure = CONFIG.IRC_SECURE,
     }
-
     io.write ('Memebot has started up as "'..CONFIG.IRC_NICK..'"\n')
 
+    -- Connect to chats, if any
     assert(CONFIG.IRC_CHANNELS == nil or type(CONFIG.IRC_CHANNELS) == 'table')
     for _, channel in ipairs(CONFIG.IRC_CHANNELS or {}) do
-        bot:join(channel)
+        join_channel(channel)
     end
 
-    while true do
+    local BOT_SHOULD_CONTINUE_RUNNING  =  true
+
+    -- Install SIGINT handler, if module loaded
+    if signal then
+        signal.signal(signal.SIGINT, function (signum)
+            io.write ' !! Received SIGINT, will shut down...\n'
+            send_to_all(BOT_FAREWELL[math.random(#BOT_FAREWELL)])
+            shutdown_memebot()
+            os.exit(128 + signum)
+        end)
+    else
+        io.write ' !! Module "posix.signal" was missing, so CTRL+C will hard-crash.\n'
+    end
+
+    -- Think loop
+    while BOT_SHOULD_CONTINUE_RUNNING do
         bot:think()
         sleep(0.5)
     end