--[[

Copyright (c) 2012 Igor Bogomazov <ygrex@ygrex.ru>

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

	No conditional branches:
	1. no hashes (as far as possible in Lua)
	2. no for/while/until loops
	3. no local operations
	4. no exceptions

	Idea: http://www.99-bottles-of-beer.net/
--]]

-- return: 0 if 0 given or 1 otherwise
local function norm(n) return #( ("1"):rep(n / n) ) end;

-- bottle phrase
local function bottle(n)
	return ""
		.. ("no more"):rep( -(norm(n) - 1) )
		.. tostring(n):rep(norm(n))
		.. " bottle"
		.. ("s"):rep( norm(n - 1) )
		.. " of beer"
		;
end;

-- the second row in verses
local function second(n)
	return ""
		.. "Take one down and pass it around, "
		.. bottle(n - 1)
		.. " on the wall.\n"
		;
end;

-- the final row in the song
local function final(n, init)
	return ""
		.. "Go to the store and buy some more, "
		.. bottle(init)
		.. " on the wall.\n"
		;
end;

-- capitalize the first letter
local function capital(s) return s:sub(1, 1):upper() .. s:sub(2) end;

-- print out verse about `n` bottles
local function verse(n, init)
	io.stdout:write(
		capital(bottle(n)),
		" on the wall, ",
		bottle(n),
		".\n"
	);
	io.stdout:write( select(norm(n) + 1, final, second)(n, init) );
	return io.stdout:write "\n";
end;

-- print out song
local function song(n, init)
	verse(n, init);
	return select(norm(n) + 1, function() end, song)(n - 1, init);
end;

-- entry point
local function main(n) return song(n, n) end;

return main(99);