module(..., package.seeall)

require("html")

-- There are two options of how to allow users to specify the type of certificate they want - the request extensions
-- and the ca signing extensions.  We have opted for making all requests look the same (same extensions) and defining
-- different ca sections for the different types of certificates.  The ca section to use when signing the request is
-- actually stored in the request filename.  The request filename is in the following format: 
-- 	'username'.'ca section name'.'common name'.csr

local configfile = "/etc/ssl/openssl.cnf"
local requestdir = "/etc/ssl/req/"

-- list of request entries that can be edited
local distinguished_names = { 	{name="countryName", label="Country Name", short="C"},
				{name="stateOrProvinceName", label="State Or Province Name", short="ST"},
				{name="localityName", label="Locality Name", short="L"},
				{name="organizationName", label="Organization Name", short="O"},
				{name="organizationalUnitName", label="Organizational Unit Name", short="OU"},
				{name="commonName", label="Common Name", short="CN"},
				{name="emailAddress", label="e-mail Address"} }
-- list of entries that may be found in cert extensions section
local extensions = { "basicConstraints", "nsCertType", "nsComment", "keyUsage", "subjectKeyIdentifier",
			"authorityKeyIdentifier", "subjectAltName", "issuerAltName" }
-- list of entries that must be found in ca section
local ca_mandatory_entries = { "new_certs_dir", "certificate", "private_key", "default_md", "database", "policy" }

-- Validate the values of distinguished names using the min/max found in the config file
local validate_distinguished_names = function(values, inputconfig)
	local config = inputconfig or getopts.getoptsfromfile(configfile)
	local distinguished_name = config.req.distinguished_name or ""
	local success = true

	for i, name in ipairs(distinguished_names) do
		local min = config[distinguished_name][name.name.."_min"] or config[distinguished_name]["0."..name.name.."_min"]
		if min and values.value[name.name] and #values.value[name.name].value < tonumber(min) then
			values.value[name.name].errtxt = "Value too short"
			success = false
		end
		local max = config[distinguished_name][name.name.."_max"] or config[distinguished_name]["0."..name.name.."_max"]
		if max and values.value[name.name] and #values.value[name.name].value > tonumber(max) then
			values.value[name.name].errtxt = "Value too long"
			success = false
		end
	end
	return success, values
end

-- Write distinguished name defaults to config file
local write_distinguished_names = function(values, inputconfig)
	local file = fs.read_file(configfile)
	local config = inputconfig or getopts.getoptsfromfile(file)
	local distinguished_name = config.req.distinguished_name or ""

	for i,name in ipairs(distinguished_names) do
		wname = name.name.."_default"
		if config[distinguished_name]["0."..name.name] then
			wname = "0."..wname
		end
		if values.value[name.name] then
			local a,b,c
			a,b,c, file = getopts.setoptsinfile(file, distinguished_name, wname, values.value[name.name].value)
		end
	end
	fs.write_file(configfile, file)
end

local create_subject_string = function(values)
	local outstr = {}
	for i,name in ipairs(distinguished_names) do
		outstr[#outstr + 1] = (name.short or name.name) .. "=" .. values.value[name.name].value
	end
	outstr[#outstr + 1] = "password="..values.value.password.value
	return "/"..table.concat(outstr, "/")
end

-- Find the sections of the config file that define ca's (ca -name option)
local find_ca_sections = function(inputconfig)
	local config = inputconfig or getopts.getoptsfromfile(configfile)
	local cert_types = {}

	for section in pairs(config) do
		local success = true
		for i,entry in ipairs(ca_mandatory_entries) do
			if not config[section][entry] then
				success = false
				break
			end
		end
		if success then
			cert_types[#cert_types + 1] = section
		end
	end

	return cert_types
end

local handle_req_clientdata = function(clientdata, defaults, config)

	-- Next, put the user values into the table
	for name,value in pairs(clientdata) do
		if defaults.value[name] then
			defaults.value[name].value = value
		end
	end

	-- Next, validate the values
	local success
	success, defaults = validate_distinguished_names(defaults, config)

	local foundcert=false
	for i,cert in ipairs(defaults.value.certtype.option) do
		if defaults.value.certtype.value == cert then
			foundcert=true
			break
		end
	end
	if not foundcert then
		success = false
		defaults.value.certtype.errtxt = "Invalid certificate type"
	end

	return success, defaults, config
end

-- FIXME we need to make sure necessary files / directories / private key are there
verifyopenssl = function()
	local retval = false
	if fs.is_file(configfile) then
		retval=true
	end
	return retval
end

getreqdefaults = function(inputconfig)
	local defaults = cfe({ type="group", value={} })
	local config = inputconfig or getopts.getoptsfromfile(configfile)
	local distinguished_name = config.req.distinguished_name or ""

	-- Get the distinguished name defaults
	for i, name in ipairs(distinguished_names) do
		defaults.value[name.name] = cfe({ label=name.label,
			value=config[distinguished_name][name.name .. "_default"]
				or config[distinguished_name]["0."..name.name.."_default"] or "",
			descr=config[distinguished_name][name.name] or config[distinguished_name]["0."..name.name] })
	end

	-- Add in the ca type default
	defaults.value.certtype = cfe({ type="select", label="Certificate Type", 
		value=config.ca.default_ca, option=find_ca_sections(config) })

	return defaults
end

setreqdefaults = function(clientdata)
	-- First, get the defaults
	local config = getopts.getoptsfromfile(configfile)
	local defaults = getreqdefaults()

	-- Then, copy in user values and validate
	local success, defaults, config = handle_req_clientdata(clientdata, defaults, config)

	-- Finally, write the values to the config file
	if success then
		write_distinguished_names(defaults, config)
	
		getopts.setoptsinfile(configfile, "ca", "default_ca", defaults.value.certtype.value)
	end

	if not success then
		defaults.errtxt = "Failed to set defaults"
	end

	return defaults
end

getnewrequest = function()
	local values = getreqdefaults()
	-- In addition to the request defaults, we need a password and confirmation
	values.value.password = cfe({ label="Password" })
	values.value.password_confirm = cfe({ label="Password confirmation" })
	return values
end

submitrequest = function(clientdata, user)
	-- First, get the defaults
	local config = getopts.getoptsfromfile(configfile)
	local defaults = getnewrequest(config)

	-- Then, copy in user values and validate
	local success, defaults, config = handle_req_clientdata(clientdata, defaults, config)

	-- Must have a common name
	if #defaults.value.commonName.value == 0 then
		defaults.value.commonName.errtxt = "Common Name cannot be blank"
		success = false
	end
	-- Check validity of password
	if #defaults.value.password.value < 4 then
		defaults.value.password.errtxt = "Password too short"
		success = false
	end
	if defaults.value.password.value ~= defaults.value.password_confirm.value then
		defaults.value.password_confirm.errtxt = "You entered wrong password/confirmation"
		success = false
	end

	if success then
		-- FIXME check to make sure same certificate or request doesn't already exist
	end

	if success then
		-- Submit the request
		local reqname = requestdir..user.."."..defaults.value.certtype.value.."."..defaults.value.commonName.value
		local subject = create_subject_string(defaults)
		local cmd = "PATH=/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin openssl req -nodes -new -config "..configfile.." -keyout "..reqname..".pem -out "..reqname..".csr -subj '"..subject.."' 2>&1"
		local f = io.popen(cmd)
		local cmdresult = f:read("*a")
		f:close()
		defaults.descr = cmdresult
	end

	if not success then
		defaults.errtxt = "Failed to submit request"
	end

	return defaults
end

listrequests = function(user)
	user = user or ""
	local list={}
	local fh = io.popen('find ' .. requestdir .. ' -name "'..user..'*.csr" -maxdepth 1')
	for x in fh:lines() do
		local name = basename(x,".csr")
		local a,b,c = string.match(name, "([^%.]*)%.([^%.]*)%.([^%.]*)")
		list[#list + 1] = {name=name, user=a, certtype=b, commonName=c}
	end
	return cfe({ type="list", value=list, label="List of pending requests" })
end