#!/usr/bin/env lua

local posix = require "posix"

local usage = [[Usage: obbs [-c config_file] COMMAND [arguments ...]

Here COMMAND is one of:
  newcfg
  init

You can also use the -c option to specify an alternative configuration
file.  (The default is the file "config.lua" in the current directory.)]]

obbs = {}
local config_file = "config.lua"
local function load_config ()
   io.write("Loading config from file '" .. config_file .. "'... ")
   dofile(config_file)
   print("done.")
end

--- Utility functions ---

local function print_table (t, lev)
   lev = lev or 0
   local ind = string.rep("\t", lev)
   
   for k,v in pairs(t) do
      if type(v)=="table" then
         print(ind ..k .. "= {")
         print_table(v, lev+1)
         print(ind .. "}")
      else
         print(ind .. k .. "=" .. tostring(v))
      end
   end
end

local function space_pad(s, n)
   return string.sub(s,1,n) .. string.rep(" ", math.max(0,n-string.len(s)))
end

local fs = {}

function fs.exists(filename)
   return io.open(filename, "r")
end

function fs.dir(path)
   return posix.dir(path)
end

function fs.mkdir(dirname)
   posix.mkdir(dirname)
end

function fs.rmdir(dirname, force)
   if force then
      for i,fname in ipairs(posix.glob(dirname .. "/*")) do
         posix.unlink(fname)
      end
   end
   assert(posix.rmdir(dirname))
end

function fs.copy(filename, destfilename)
   src = assert(io.open(filename,"r"))
   dest = assert(io.open(destfilename,"w"))

   dest:write(src:read("*all"))
   dest:close()
   src:close()
end

function fs.touch(filename)
   fh = assert(io.open(filename,"w"))
   fh:close()
end

function fs.mktempdir()
   return posix.mkdtemp("/tmp/obbs-XXXXXX")
end

--- Message parsing ---

local msgs = {}
function Message(msg)
   msgs[msg.number] = msg
end

--- QWK formatting ---

local qwk = {}

function qwk.write_control(target_dir, obbs, user_name)
   local cf = assert(io.open(target_dir .. "/CONTROL.DAT", "w"))

   cf:write(obbs.name .. "\r\n")
   cf:write("\r\n") -- BBS location
   cf:write("\r\n") -- BBS phone number
   cf:write(obbs.sysop .. "\r\n")
   cf:write("12345," .. obbs.bbsid .. "\r\n")
   cf:write(os.date("%d-%m-%Y,%X") .. "\r\n") -- packet creation time
   cf:write(user_name .. "\r\n")
   cf:write("\r\n")
   cf:write(0 .. "\r\n")
   cf:write(0 .. "\r\n") -- TODO: Number of messages in packet
   cf:write(#obbs.conferences-1 .. "\r\n") -- Index of final conference
   for i,v in ipairs(obbs.conferences) do
      cf:write(i-1 .. "\r\n")
      cf:write(v .. "\r\n")
   end

   cf:write("HELLO\r\n")
   cf:write("NEWS\r\n")
   cf:write("GOODBYE\r\n")

   cf:close()
end

function qwk.write_message (target_dir, obbs)
   local mf = assert(io.open(target_dir .. "/MESSAGES.DAT", "w"))

   local pkt_msg_num = 0

   mf:write(space_pad("Produced by Qmail...Copyright (c) 1987 by Sparkware." ..
                      "  All Rights Reserved", 128))

   for cnum,cname in ipairs(obbs.conferences) do
      msgs = {}
      dofile(obbs.path .. "/conferences/" .. cname .. ".msgs")
      for i,msg in ipairs(msgs) do
         pkt_msg_num = pkt_msg_num + 1
         qwk.write_message_header_block(mf, obbs, cnum, pkt_msg_num, msg)
         qwk.write_message_blocks(mf, obbs, msg)
      end
   end

   mf:close()
end

function qwk.write_message_header_block(mf, obbs, conf_num, pkt_msg_num, msg)
   mf:write(" ") -- Message status flag
   mf:write(space_pad(tostring(msg.number), 7))
   mf:write(msg.date) -- mm-dd-yy
   mf:write(msg.time) -- hh:mm
   mf:write(space_pad(string.upper(msg.to), 25))
   mf:write(space_pad(string.upper(msg.from), 25))
   mf:write(space_pad(msg.subject, 25))
   mf:write(string.rep(" ", 12)) -- Password (blank)

   if msg.reply_to then
      mf:write(space_pad(tostring(msg.reply_to), 8))
   else
      mf:write(string.rep(" ", 8))
   end

   nblocks = math.ceil(string.len(msg.text)/128) + 1
   mf:write(space_pad(tostring(nblocks), 6)) -- number of blocks including header

   mf:write("\xe1") -- flag indicating message is "active" (not "to be killed")
   mf:write(string.pack("I2",conf_num))
   mf:write(string.pack("I2",pkt_msg_num))
   mf:write(" ") -- No network tag-line present
end

function qwk.write_message_blocks(mf, obbs, msg)
   mf:write((string.gsub(msg.text, "\n", "\xe3")))
   
   local padding = (128 - (string.len(msg.text) % 128)) % 128
   mf:write(string.rep("\0",padding))
end

--- Commands ---

local cmd = {}

-- Send default configuration to stdout
function cmd.newcfg ()
   print [[
-- OBBS Configuration File

obbs.path = "." -- Path to OBBS root

obbs.name = "My OBBS Name"
obbs.bbsid = "MYOBBSID" -- max 8 char
obbs.sysop = "Sysop Name"

-- obbs.hello_file = "hello"
-- obbs.news_file = "news"
-- obbs.goodbye_file = "goodbye"

obbs.conferences = {
   "Announcements",
   "General",
   "Meta"
}
]]
end

-- Initialise conference directory structure
function cmd.init ()
   load_config()

   if fs.exists(obbs.path .. "/conferences") or
      fs.exists(obbs.path .. "/incoming") or
      fs.exists(obbs.path .. "/outgoing") then
      print("One or more OBBS directories already exist. Aborting.")
      return
   end

   fs.mkdir(obbs.path .. "conferences")
   for i,v in ipairs(obbs.conferences) do
      fs.touch(obbs.path .. "conferences/" .. v .. ".msgs")
   end

   fs.mkdir(obbs.path .. "incoming")
   fs.mkdir(obbs.path .. "outgoing")
end

-- Pack 
function cmd.pack ()
   load_config()

   if not arg[1] then
      print "Usage: obbs pack USER"
      return
   end

   local user_name = arg[1]

   local target_dir = fs.mktempdir()

   -- CONTROL.DAT
   qwk.write_control(target_dir, obbs, user_name)

   -- Copy BBS welcome, news and goodbye files

   if obbs.hello and fs.exists(obbs.hello) then
      fs.copy(obbs.hello, target_dir .. "/HELLO")
   else
      fs.touch(target_dir .. "/HELLO")
   end

   if obbs.news and fs.exists(obbs.news) then
      fs.copy(obbs.news, target_dir .. "/NEWS")
   else
      fs.touch(target_dir .. "/NEWS")
   end

   if obbs.news and fs.exists(obbs.goodbye) then
      fs.copy(obbs.goodbye, target_dir .. "/GOODBYE")
   else
      fs.touch(target_dir .. "/GOODBYE")
   end

   -- Pack messages

   qwk.write_message(target_dir, obbs)

   -- Create archive in outgoing

   os.execute("zip -rj " .. obbs.path ..
              "/outgoing/" .. obbs.bbsid ..
              ".qwk " .. target_dir)

   fs.rmdir(target_dir, true)
end

-- Main

local function main()
   if #arg > 2 and arg[1]=="-c" then
      config_file = arg[2]
      table.remove(arg, 1)
      table.remove(arg, 1)
   end
   
   if #arg < 1 then
      print(usage)
   else
      if cmd[arg[1]] then
         local f = cmd[arg[1]]
         table.remove(arg,1)
         f()
      else
         print("Unknown command '" .. arg[1] .. "'")
         print(usage)
      end
   end
end

main()
.