Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
finite state machine - ussd
(ns ussd.fsm-utils
(:require
[clojure.string :as str]
[clojure.edn :as edn]
[ussd.sms :as sms]))
(defn check-via
[via]
(let [choices (:choices (edn/read-string (slurp "../../ussd_fsm.edn")))]
(if (contains? choices via)
via
(if (str/blank? via)
:empty
:not-empty))))
(defn user-response-for-query
[past-states query]
(some-> (some #(when (= (:from %) query) %) past-states)
:user-response))
(defn print-to-file
[file data]
(with-open [writer (clojure.java.io/writer file)]
(clojure.pprint/pprint data writer)))
(defn get-next-state
[fsm current-state via]
(let [checked-via (check-via via)]
(get-in fsm [current-state checked-via :next-state])))
(defn get-next-text
[fsm current-state via]
(let [checked-via (check-via via)]
(get-in fsm [current-state checked-via :text])))
(defn does-session-exist?
[storage-location session-id]
(let [parsed-text (slurp storage-location)]
(or (str/blank? parsed-text) (contains? (edn/read-string parsed-text) session-id))))
(defn new-storage
[{:keys [storage-location fsm session-id phone-number network-code service-code text]}]
(let [next-state (get-in fsm [:start :init :next-state])
next-text (get-in fsm [:start :init :text])
storage (edn/read-string (slurp storage-location))]
(if storage
(assoc storage session-id {:phone-number phone-number
:network-code network-code
:service-code service-code
:text text
:current-state next-state
:current-text-response next-text
:past-state [{:from :start
:via :init
:to next-state}]})
{session-id {:phone-number phone-number
:network-code network-code
:service-code service-code
:text text
:current-state next-state
:current-text-response next-text
:past-state [{:from :start
:via :init
:to next-state}]}})))
(defn existing-storage
[{:keys [storage-location fsm session-id phone-number network-code service-code text]}]
(let [storage (edn/read-string (slurp storage-location))
current-state (get-in storage [session-id :current-state])
choice-or-not (last (str/split text #"\*"))
next-state (get-next-state fsm current-state choice-or-not)
next-text (get-next-text fsm current-state choice-or-not)
session-map (get storage session-id)]
(if next-state
(->> (merge session-map {:text text
:current-state next-state
:current-text-response next-text
:past-state (conj (:past-state session-map) {:from current-state
:via (check-via choice-or-not)
:to next-state
:user-response choice-or-not})})
(assoc storage session-id))
(->> (merge session-map {:text text
:past-state (conj (:past-state session-map) {:from current-state
:via choice-or-not
:user-error true
:user-response choice-or-not
:to current-state})})
(assoc storage session-id)))))
(defn new-session-scenario
[{:keys [storage-location fsm session-id phone-number network-code service-code text] :as all}]
(let [storage (new-storage all)
current-text-response (get-in storage [session-id :current-text-response])
current-state (get-in storage [session-id :current-state])]
(do (print-to-file storage-location storage)
(if (= current-state :finish)
(str "END " current-text-response)
(str "CON " current-text-response)))))
(defn existing-session-scenario
[{:keys [storage-location fsm session-id phone-number network-code service-code text] :as all}]
(let [storage (existing-storage all)
current-text-response (get-in storage [session-id :current-text-response])
current-state (get-in storage [session-id :current-state])
email (user-response-for-query (get-in storage [session-id :past-state]) :query-email)
username (user-response-for-query (get-in storage [session-id :past-state]) :query-username)]
(do (print-to-file storage-location storage)
(if (= current-state :finish)
(do
(sms/send-sms
{:phone-number phone-number
:message (str "Thank you for participating. You have successfully registered\nemail: " email "\nusername: " username "\n\n")})
(str "END " current-text-response))
(str "CON " current-text-response)))))
(defn ussd
[{:keys [storage-location fsm session-id phone-number network-code service-code text]
:as all}]
(if (does-session-exist? storage-location session-id)
(existing-session-scenario all)
(new-session-scenario all)))
(def ussd-interceptor
{:name ::ussd-interceptor-2
:enter (fn [context]
(let [params (get-in context [:request :form-params])
session-id (get params :sessionId)
phone-number (get params :phoneNumber)
network-code (get params :networkCode)
service-code (get params :serviceCode)
text (get params :text)
fsm (:fsm (edn/read-string (slurp "../../ussd_fsm.edn")))]
(assoc context :response {:status 200
:body (ussd {:storage-location "../../storage/database.edn"
:fsm fsm
:session-id session-id
:phone-number phone-number
:network-code network-code
:service-code service-code
:text text})})))})
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment