#!/usr/bin/env luajit


-- Most of this _ stuff was copied from apt-panopticon.
local _ = {}

_.version = '0.0 crap'

_.D = function(s)	print('DEBUG    ' .. s) end
_.I = function(s)	print('INFO     ' .. s) end
_.T = function(s)	print('TIMEOUT  ' .. s) end
_.W = function(s)	print('WARNING  ' .. s) end
_.E = function(s)	print('ERROR    ' .. s) end
_.C = function(s)	print('CRITICAL ' .. s) end
local D = _.D
local I = _.I
local T = _.T
local W = _.W
local E = _.E
local C = _.C


_.readCmd = function(cmd)
    local result = {}
    local output = io.popen(cmd)
    if nil ~= output then
	for l in output:lines() do
	    table.insert(result, l)
	end
    end
    -- While this does return the same things as os.execute(), it's just as useless.
    output:close()
    return result
end


_._ = function(c)
    local exe = {status = 0, lines = {}, logging = false, showing = false, cmd = '', command = c}
    local n = 0

    exe.cmd = '{ '
    if 'table' == type(c) then
	for i, l in ipairs(c) do
	    n = n + 1
	    exe.cmd = exe.cmd .. l .. ' ; '
	end
    elseif 'string' == type(c) then
	for l in string.gmatch(c, "\n*([^\n]+)\n*") do
	    if '' ~= l then
		n = n + 1
		exe.cmd = exe.cmd .. l .. ' ; '
	    end
	end
    end
    exe.cmd = exe.cmd .. ' } '
    if 1 == n then exe.cmd = c end

    function exe:log()
	self.logging = true
	return self
    end

    function exe:show()
	self.showing = true
	return self
    end

    function exe:Nice(c)
	if nil == c then
	    self.cmd = 'ionice -c3 nice -n 19 ' .. self.cmd
	else
	    self.cmd = self.cmd .. ' ionice -c3 nice -n 19 ' .. c .. ' '
	end
	return self
    end

    function exe:timeout(c)
	-- timeout returns a status of - command status if --preserve-status; "128+9" (actually 137) if --kill-after ends up being done; 124 if it had to TERM; command status if all went well.
	-- --kill-after means "send KILL after TERM fails.
	if nil == c then
	    self.cmd = 'timeout --kill-after=10.0 --foreground 42.0s ' .. self.cmd
	else
	    self.cmd = 'timeout --kill-after=10.0 --foreground ' .. c .. ' ' .. self.cmd
	end
	return self
    end

    function exe:also(c)	-- Should be called "then" but that's a reserved word.
	if nil == c then c = '' else c = ' ' .. c end
	self.cmd = self.cmd .. '; ' .. c .. ' '
	return self
    end

    function exe:And(c)
	if nil == c then c = '' else c = ' ' .. c end
	self.cmd = self.cmd .. ' && ' .. c .. ' '
	return self
    end

    function exe:Or(c)
	if nil == c then c = '' end
	self.cmd = self.cmd .. ' || ' .. c .. ' '
	return self
    end

    function exe:noErr()
	self.cmd = self.cmd .. ' 2>/dev/null '
	return self
    end

    function exe:noOut()
	self.cmd = self.cmd .. ' 1>/dev/null '
	return self
    end

    function exe:wait(w)
	self.cmd = self.cmd .. ' && touch ' .. w .. ' '
	return self
    end

    function exe:Do()
    --[[    "The condition expression of a control structure can return any
	    value. Both false and nil are considered false. All values different
	    from nil and false are considered true (in particular, the number 0
	    and the empty string are also true)."
	    says the docs, I beg to differ.]]
	if true == self.logging then D(" executing - " .. self.cmd) end
	--[[ Damn os.execute()
	    Lua 5.1 says it returns "a status code, which is system-dependent"
	    Lua 5.2 says it returns true/nil, "exit"/"signal", the status code.
	    I'm getting 7168 or 0.  No idea what the fuck that is.
	local ok, rslt, status = os.execute(s)
	]]
	self.lines = _.readCmd(self.cmd .. '; echo "$?"', 'r')
	-- The last line will be the command's returned status, collect everything else in lines.
	self.status = tonumber(self.lines[#self.lines])
	self.lines[#self.lines] = nil
	if true == self.showing then for i, l in ipairs(self.lines) do D(l) end end
	if (137 == self.status) or (124 == self.status) then
	    T("timeout killed " .. self.status .. ' ' .. self.command)
	elseif (nil == self.status) then
	    I("STATUS |" .. "NIL" .. '| ' .. self.command)
	elseif (0 ~= self.status) then
	    I("STATUS |" .. self.status .. '| ' .. self.command)
	end
	return self
    end

    function exe:fork(host)
--	if nil ~= host then self.cmd = self.cmd .. ';  r=$?; if [ $r -ge 124 ]; then echo "$r ' .. host .. ' failed forked command ' .. string.gsub(self.cmd, '"', "'") .. '"; fi' end
	self.cmd = '{ ' .. self.cmd .. ' ; } & '
	if true == self.logging then D(" forking - " .. self.cmd) end
	os.execute(self.cmd)
	return self
    end

    function exe:forkOnce()
	if _.running(self.command) then
	    D('Already running ' .. self.command)
	else
	    self:fork()
	end
    end

    return exe
end

local __ = _._

_.runnable = function(c)
    return ( 0 == __('which ' .. c):Do().status )
end

_.running = function(c)
	return ( 1 ~= tonumber(__("pgrep -u $USER -cf " .. c):Do().lines[1]) )
end

_.exists = function(f)
    local h, e = io.open(f, "r")
    if nil == h then return false else h:close();  return true end
end

_.killEmAll = function(all)
    for i,l in ipairs(all) do
	local c = 0
	while 0 ~= tonumber(__("pgrep -u $USER -xc " .. l):Do().lines[1]) do
	    local s = 'TERM'
	    if c > 1 then s = 'KILL'; __("sleep " .. c):Do() end
	    __("pkill -" .. s .. " -u $USER -x " .. l):log():Do()
	    c = c + 1
	end
    end
end



return _