if os.getenv("comspec") then
	sql_library = "../cgilua53/lua_sqlite3.dll"
	
elseif os.getenv("lua_sql") then
	sql_library = os.getenv("lua_sql")
else
	sql_library = "../cgilua53/lua_sql.so"
end
binary_library = "../cgilua53/binstd.dll"
package.path = package.path .. ";../cgilua53/?.lua"

function print_errors(script_name, f)
	local ok,err = xpcall(f, debug.traceback)

	if not ok then
		header()
		print("Problem in " .. script_name .. "<br>")
		print(string.gsub(err, "\n", "<br>"))
		os.exit()
	end
end

print_errors ("cgi.lua",function() 

	write = io.write
	local insert = table.insert
	local find = string.find
	local sub = string.sub
	local len = string.len
	local write = io.write

	--iterator that returns the pairs in order
	function sorted_pairs(t, f)
		local a = {}
		for n in pairs(t) do
			table.insert(a, n)
		end
		table.sort(a, f)
		local i = 0
		local iter = function()
			i = i + 1
			if a[i] == nil then
				return nil
			else
				return a[i], t[a[i]]
			end
		end
		return iter
	end

	--use this function returns each part of the arg seperated by the seperator in a table element. That is, split("apple banana"," ") would return {"apple","banana")
	function split(arg, seperator, magic)
		seperator = seperator or " "
		local  t = {}
		local i, j = string.find(arg, seperator, 1, not magic)
		if not i then 
			table.insert(t, arg)
		end
		while i do
			table.insert(t, string.sub(arg, 1, i - 1))
			arg = string.sub(arg, j + 1)
			i, j = string.find(arg, seperator, 1, not magic)
			if not i then
				table.insert(t, arg)
			end
		end
		return t 
	end

	--returns the string passed in but with the extra spaces to left and right trimmed
	local hex = "0123456789ABCDEF"
	function trim(s)
		while string.sub(s, 1, 1) == " " do
			s = string.sub(s, 2)
		end
		while string.sub(s, -1, -1) == " " do
			s = string.sub(s, 1, -2)
		end
		return s
	end

	--function(filename): reads an entire textfile into a varible which is returned
	function slurp(filename)
		local old_input = io.input()
		io.input(filename)
		local result = io.read "*a"
		io.close(io.input())
		pcall(io.input, old_input)
		return result
	end

	--reads an entire datafile into a variable which is returned
	function file2data(filename)
		local file_handle = io.open(filename, "rb")
		local result = file_handle:read "a"
		file_handle:close()
		return result
	end

	--writes the contents of a string to a file
	function string2file(string, filename)
		local file_handle = io.open(filename, "w")
		file_handle:write(string)
		file_handle:close()
	end

	--writes data to file
	function data2file(data, filename)
		local file_handle = io.open(filename, "wb")
		file_handle:write(data)
		file_handle:close()
	end

	--returns true if file is readable
	function file_exists(name)
		local f = io.open(name, "r")
		if f ~= nil then
			io.close(f) 
			return true
		else
			return false 
		end
	end

	function convert_from_hex(s)
		local result = 0
		for i = 1,len(s) do
			local value = find(hex,sub(s, i, i)) or 0
			result = result * 16 + value - 1
		end
		return string.char(result)
	end

	-- this will replace all %xx with characters to decode
	function decode_from_url(value)
		value = string.gsub(value, "%+", " ") -- + becomes space
		value = string.gsub(value, "%%(..)", convert_from_hex) --%99  percent and two characters
		return value
	end

	-- make a string url safe by replacing non alphanumeric characters with %xx where xx is a hex code but allow /
	function encode_to_url(value)
		return string.gsub(value, "[^%w/]", function (a)
			return string.upper(string.format("%%%02x", string.byte(a))) -- %% is literal percent 0 is leading zero, 2 digits, x specifies hexidecimal 
		end) --non alpha numeric digits
	end

	function query_string_to_table(s)

		--split from string
		local t = split(s, "&")
		local result = {}
		local x

		for k, v in pairs(t) do
			x = split(v, "=")
			local value=x[2]
			if value ~= nil then
				--convert from hex
				value = decode_from_url(value)
				result[x[1]] = value
			end
		end

		return result
	end

	function cookie_string_to_table(s)

		--split from string
		local t = split(s, ";") --this is different 
		local result = {}
		local x

		for k, v in pairs(t) do
			x = split(v, "=")
			local value = x[2]
			if value ~= nil then
				--convert from hex
				value = decode_from_url(value)
				result[trim(x[1])] = value
			end
		end

		return result
	end

	--POST elements are tables with name and data and other keys
	function multipart_form_to_table(s)
		s = s or INPUT
		local content_type = os.getenv "CONTENT_TYPE"
		content_type = string.gsub(content_type, '\"', "") --no quotes
		local boundary = "--" .. sub(content_type, string.find(content_type, "boundary=") + #"boundary=") .. "\r\n"
		s = sub(s, 1, -(#boundary + 3))
		local result = {}

		for k_item, v_item in ipairs(split(s, boundary)) do
			local t = {}
			local position = 1
			local done = false
			-- repeat finding the next line until blank, then put that into data
			repeat
				local new_position = string.find(v_item, "\r\n", position, true)
				if not new_position then
					new_position = #v_item
				end
				local v = sub(v_item, position, new_position - 1)
				if sub(v, 1, 19) == "Content-Disposition" then
					local content_disp = split(v, "; ")
					for k_content_disp, v_content_disp in pairs(content_disp) do
						local value = split(v_content_disp, "=") 
						if value[2] then
							t[value[1]] = sub(value[2], 2, -2) -- removing quotes
						end
					end
				end

				if sub(v, 1, 12) == "Content-Type" then
					t["Content-Type"] = sub(v, 15)
				end

				if v == "" then
					t.data = sub(v_item, position + 2, -3)
					done = true
				end

				if not done then
					position = new_position + 2
				end
			until done

			if t.name then
				result[t.name] = t
			end
		end
		return result
	end

	--encode from string to something safe to display on a form, that is, turn & into &amp, turn > int &gt and turn < into &lt
	--this will sanitize strings going to html
	function escape_html(s)
		s = tostring(s)
		s = string.gsub(s, "&", "&amp;")
		s = string.gsub(s, "'", "&apos;")
		s = string.gsub(s, '"', "&quot;")
		s = string.gsub(s, ">", "&gt;")
		s = string.gsub(s, "<", "&lt;")
		s = string.gsub(s, "\n", "<br>")
		s = string.gsub(s, "&amp;(#%d+;)", "&%1")
		return s
	end

	--encode from string to something safe to display on a form, that is, turn & into &amp, turn > int &gt and turn < into &lt
	--this will sanitize strings going to html
	--no turning \n to <br>
	function escape_html2(s)
		s = tostring(s)
		s = string.gsub(s, "&", "&amp;")
		s = string.gsub(s, "'", "&apos;")
		s = string.gsub(s, '"', "&quot;")
		s = string.gsub(s, ">", "&gt;")
		s = string.gsub(s, "<", "&lt;")
		s = string.gsub(s, "&amp;(#%d+;)", "&%1")
		return s
	end

	function table_to_table(t)
		local result = '<table border="1">'
		for k, v in sorted_pairs(t) do
			result = result .. '<tr><td>' .. escape_html(k) .. '</td><td>' .. escape_html(v) .. "</td></tr>"
		end
		write(result .. "</table>")
	end

	pack = table.pack

	--runs a string as lua code. if die is true, then throws an error on errors. Otherwise, returns false, and errors. Will return true and all results if there is a result. Will return all results if die is true (true isn't needed, since any error would have caused an error instead of a result)
	function eval(expr, die)
		local ok, result = load(expr)
		if not ok then
			if die then 
				error(result,2) 
			else
				return false, result
			end
		end
		local t = pack(pcall(ok))
		ok = t[1] --first result is status code
		table.remove(t, 1) --toss it, now t is a table of results
		if not ok then
			if die then 
				error(t[1], 2)
			else 
				return false, t[1]
			end
		end
		if die then
			return table.unpack(t) 
		end
		return true, table.unpack(t)
	end

--runs a string as lua code. if die is true, then throws an error on errors. Otherwise, returns false, and errors. Will return true and all results if there is a result. Will return all results if die is true (true isn't needed, since any error would have caused an error instead of a result)
--env parameters is the environment
function eval2(expr, env, die)
	local ok, result = load(expr, expr, "t", env)
	if not ok then
		if die then 
			error(result,2) 
		else
			return false, result
		end
	end
	local t = pack(pcall(ok))
	ok = t[1] --first result is status code
	table.remove(t, 1) --toss it, now t is a table of results
	if not ok then
		if die then 
			error(t[1], 2)
		else 
			return false, t[1]
		end
	end
	if die then
		return table.unpack(t) 
	end
	return true, table.unpack(t)
end

	--io.write everything in a table, and tables under it, in a format that can be dofile to recreate the table. Can't be endlessly recursive, or contain formats it doesn't understand. f is a function that can be run to try to make sense of formats other than number,string, table and boolean.
	function serialize(o,f)
		if type(o) == "number" then 
			io.write(o)
		elseif type(o) == "string" then 
			io.write(string.format("%q", o))
		elseif type(o) == "boolean" then 
			io.write(tostring(o))
		elseif type(o) == "table" then 
			io.write("{\n")

			for k, v in pairs(o) do

				io.write(" [")
				serialize(k, f)
				io.write("] = ")

				serialize(v, f)
				io.write(", \n")
			end

			io.write("}\n")
		else
			if f then 
				f(o) 
			else 
				error("cannot serialize a " .. type(o), 2)
			end
		end
	end

	--This returns a string variable created out of the list of values given

	--for example.. serial(1,3,"alpha",true,{"elephant"})
	--returns the string '1,3,"alpha",true,{ [1] = "elephant", }'
	function serial(...)
		local arg = table.pack(...)
		local s = {}
		local insert = table.insert
		for i = 1, arg.n do
			local o = arg[i]
			local t = type(o)
			if t == "number" then 
				insert(s, o)
			elseif t == "string" then 
				insert(s, string.format("%q", o))
			elseif t == "boolean" then 
				insert(s, tostring(o))
			elseif t == "nil" then 
				insert(s, "nil")
			elseif t == "table" then 
				local a
				a="{"

				for k, v in pairs(o) do
					a = a.." [" .. serial(k) .. '] = ' .. serial(v) .. ', '
				end 

				a = a .. "}"
				insert(s, a)

			else 
				error("cannot serial a " .. t, 2)
			end 
		end 

		return table.concat(s, ',')
	end


	--clones a table, meaning to create another seperate table with the same values. can't be endlessly recursive
	function copy_table(source)
		if type(source) ~= "table" then 
			error("copy_table - argument must be a table", 2) 
		end
		local dest = {}
		for k, v in pairs(source) do
			if type(v) == "table" then
				dest[k] = copy_table(v)
			else
				dest[k] = v
			end
		end
		return dest
	end

	local database_name
	function query_and_close(query, dbname)
		if not sql_open then 
			package.loadlib(sql_library, "lua_sqlite3")() 
		end
		if dbname then 
			database_name = dbname 
		end
		local db = sql_open(database_name)
		local result = sql_query(db, query)
		sql_close(db)
		return result
	end

	function initial_query(query, dbname)
		if not sql_open then 
			package.loadlib(sql_library, "lua_sqlite3")() 
		end
		if dbname then 
			database_name = dbname 
		end
		local db = sql_open(database_name)
		local result = sql_query(db, query)
		return result, db
	end

	function display_query(query, dbname, nullvalue)
		local result = query_and_close(query, dbname)
		nullvalue = nullvalue or "(null)"
		print "<table border=1>"

		--collecting every header in every row, due to nil results destroying the header
		local headers = {}
		for k, v in pairs(result) do
			for k, v in pairs(v) do
				headers[k] = true
			end
		end

		--printing the headers out
		for k, v in sorted_pairs(headers) do
			print "<th>"
			print (escape_html(k))
			print "</th>"
		end

		--now the values, including the nil results
		for k, v in ipairs(result) do
			print "<tr>"
			for h, _ in sorted_pairs(headers) do
				print "<td>"
				print (escape_html(v[h] or nullvalue))
				print "</td>"
			end
			print "</tr>"

		end
		print "</table>"
	end

	--checks if the table is empty
	function is_empty(tabl)
		if type(tabl) ~= "table" then
			error("is_empty: not a table", 2)
		end
		for _ in pairs(tabl) do
			return false
		end
		return true
	end

	--given string s with single quotes such as let's return 'let''s'
	--this should sanitize to a database query
	function escape_string(s)
		if s == nil then 
			return "NULL"
		end
		s = tostring(s)
		s = string.gsub(s, "'", "''")
		return "'" .. s .. "'"
	end

	function escape_number(n)
		return tonumber(n) or "NULL"
	end

	local header_written
	function header()
		if not header_written then
			write "Content-type: text/html\n\n"
			header_written = true
		end
	end

	--sets a cookie header
	function cookie(name, contents, expire_days)
		local cookie_time = os.date("!%a, %d-%b-%Y %H:%M:%S GMT",(os.time() + expire_days * 24 * 60 * 60))
		local value =  "Set-Cookie: " .. encode_to_url(name) .. "=" .. encode_to_url(contents) .. ";expires=" .. cookie_time .. "\n"
		io.write(value)
		return value
	end

	function debug_log(string) --don't name this debug, that's a libary
		local file = io.open("debug.txt", "a")
		file:write(tostring(string) .."\n")
		file:close()
	end

	--main
	if os.getenv("CONTENT_TYPE") == "application/x-www-form-urlencoded" then
		INPUT = io.read("*a")
		POST = query_string_to_table(INPUT)
	elseif os.getenv("CONTENT_TYPE") ~= nil then
		if os.getenv("comspec") then
			package.loadlib(binary_library, "luaopen_binstd")()
		end
		INPUT = io.read("*a")
		POST = multipart_form_to_table()
	else
		POST = {}
	end

	GET = query_string_to_table(os.getenv("QUERY_STRING") or "")
	COOKIE = cookie_string_to_table(os.getenv("HTTP_COOKIE") or "")

end)