--require router and set locals for necessary request info
local router = require("router").new()
--lapis for config
local config = require("lapis.config").get()
--json
local cjson = require("cjson")
--other locals
local resty_random = require "resty.random"
local resty_str = require "resty.string"
local uri_args = ngx.req.get_uri_args()

--crypto
local aes = require "resty.aes"
local base64 = require "base64"

--temporary dict for valid bundle identifiers and corresponding secret keys
--dict: {
	--[
		--bundle_id: SECRET_KEY
	--]
--}
local valid_ids = {
	['com.venuenextinc.AppLink'] = "78d2e80f4f98a8e9d50a894df8f9a90b"
}

--temporary dict for generated AppLink access tokens
local valid_tokens = {
	['com.venuenextinc.AppLink'] = 'a5e01e3cde65d4d85340ef6e653561db'
}

-- GET: APP LINK TOKEN
router:get("/venuenext/austin/token/app_link_token.json.enc", function(params)
  ngx.header.etag = etag

  local bundle_id = uri_args['bundleid']

  if bundle_id == nil then
    local response_json = cjson.encode({
      error_message = 'No bundle identifier provided.'
    })
    ngx.status = 400

  	return ngx.print(response_json)
  else
  	local check_bundle_id = valid_ids[bundle_id]

  	if check_bundle_id == nil then
  		local response_json = cjson.encode({
  			error_message = 'Bundle identifier provided is invalid.'
      })
		ngx.status = 400

		return ngx.print(response_json)
    end
  end

  local access_token = valid_tokens[bundle_id]

  if access_token == nil then
    local response_json = cjson.encode({
      error_message = 'Cannot create access token'
    })
    ngx.status = 401

    return ngx.print(response_json)
  end

  response_json = cjson.encode({applink_token = access_token})

  -- get secret key
  local secret_key = valid_ids[bundle_id]

  -- aes128 cbc md5 encrypt no IV, no salt
  local aes_128_cbc_md5 = aes:new(secret_key)
  local encrypted = aes_128_cbc_md5:encrypt(response_json)

  -- base64 encode then ship off
  local base64_encoded = base64.encode(encrypted)

  ngx.status = 200
  return ngx.print(cjson.encode({base64_encoded}))
end)

-- GET: VERIFY APP LINK TOKEN
router:get("/venuenext/austin/token/verify", function(params)
  ngx.header.etag = etag

  local bundle_id = uri_args['bundleid']
  local enc_app_token = uri_args['applinktoken']

  -- Check bundle id
  if bundle_id == nil then
  	local response_json = cjson.encode({
  		error_message = 'No bundle identifier provided.',
  		errors = cjson.encode({
  			bundle_id = 'Bundle identifier needs to be provided to Venue Next for valid partner apps.',
  			enc_app_token = 'AppLink token to be provided from Venue Next app Deep Link and signed with your app\'s SECRET_KEY'
      })
    })
    ngx.status = 400
    return ngx.print(response_json)
  end

  -- Check app token
  if enc_app_token == nil then
  	local response_json = cjson.encode({
		  error_message = 'No signed AppLink token provided.',
		  errors = cjson.encode({
        bundle_id = 'Bundle identifier needs to be provided to Venue Next for valid partner apps.',
  		  enc_app_token = 'AppLink token to be provided from Venue Next app Deep Link and signed with your app\'s SECRET_KEY'
		  })
    })
    ngx.status = 400
    return ngx.print(response_json)
  end

  return ngx.print(cjson.encode({enc_app_token}))

  -- Check Bundle Identifier is valid and participating
  local check_bundle_id = valid_ids[bundle_id]
  local check_token = valid_tokens[bundle_id]

  if check_bundle_id == nil then
    local response_json = cjson.encode({
		  error_message = 'Bundle identifier provided is invalid.'
    })
    ngx.status = 400
    return	ngx.print(response_json)
  else
  	-- base64 decode token
    local base64_decoded = base64.decode(enc_app_token)

    -- aes128 cbc md5 decrypt
    local aes_128_cbc_md5 = aes:new(secret_key)
    local decrypted = aes_128_cbc_md5:decrypt(base64_decoded)

    if check_token == decrypted then
      ngx.status = 200
      return
    else
      local response_json = cjson.encode({
        error_message = 'Token is not valid for bundle identifier provided.',
        errors = cjson.encode({
          bundle_id = 'Bundle identifier provided is valid.',
          enc_app_token = 'Token is not valid for bundle identifier provided.'
        })
      })

      ngx.status = 401
      return ngx.print(response_json)
    end
  end
end)

-- sends the request parts to be routed
local ok, errmsg = router:execute(ngx.var.request_method, ngx.var.uri, ngx.req.get_uri_args())

if not ok then
  ngx.status = 404
  ngx.log(ngx.STDERR, errmsg)
end