tiny_blockchain.clj

(ns clj-tiny-blockchain.core
  (:require [buddy.hashers :as hashers]
            [java-time :as t]))

(defn- now []
  (t/local-date-time))

(defn- hash-block [m]
  (let [{:keys [index timestamp data previous-hash]} m]
    (-> (str index timestamp data previous-hash)
        (hashers/derive {:alg :pbkdf2+sha256}))))

(defn block [m]
  (assoc m :hash (hash-block m)))

(defn genesis-block []
  (-> {:index 0
       :timestamp (now)
       :data "Genenis Block"
       :previous-hash "0"}
      block))

(defn next-block [last-block]
  (let [index (-> last-block :index inc)]
    (-> last-block
        (assoc :index index
               :timestamp (now)
               :data (str "Hey! I'm block " index)
               :previous-hash (:hash last-block))
        block)))

(defn -main
  []
  (doseq [blk (take 10 (iterate next-block (genesis-block)))]
    (println (format "Block #%d : %s" (:index blk) (:hash blk)))
    (println (format "Previous: %s" (:previous-hash blk)))
    (println "----")))