(ns testmultiple.core
  (:require
    [clojure.java.jdbc :as jdbc]
    [compojure.core :refer [defroutes GET ANY routes context]]
    [conman.core :as conman]
    [mount.core :refer [defstate]]))

(def database-urls {:DB1 "jdbc:mysql://localhost:3306/DB1?user=DB1_user&password=DB1_password"
                    :DB2 "jdbc:mysql://localhost:3306/DB2?user=DB2_user&password=DB2_password"})

;; Connects to all databases in pool-specs
(defn connect!
  [pool-specs]
  (reduce merge (map (fn [pool-spec]
                       {(keyword (key pool-spec)) (conman/connect! {:jdbc-url (val pool-spec)})}) pool-specs)))

;; Disconnect from all databases in db-connections
(defn disconnect!
  [db-connections]
  (map (fn [db] (conman/disconnect! (val db))) db-connections))

;; Establish connections to all databases
;; and store connections in *dbs*
(defstate ^:dynamic *dbs*
          :start (connect!
                   database-urls)
          :stop (disconnect! *dbs*))

;; Bind queries to *db* dynamic variable which is bound
;; to each clients database before executing queries
;; The queries file defines the query get-user which
;; returns user by user id
(def ^:dynamic *db* nil)
(conman/bind-connection *db* "sql/queries.sql")

(mount.core/start)

; Define function that executes in current *db* binding
(defn getuser [id] (get-user {:id id}))

; Works, the user with Id 670 is returned from DB1
(with-bindings {#'*db* (:DB1 *dbs*)} (getuser 670))

; Works, the user with Id 670 is returned from DB2
(with-bindings {#'*db* (:DB2 *dbs*)} (getuser 670))

(defn serve-page1 [] (str "page1" (getuser 670)))
(defn serve-page2 [] (str "page2" (getuser 670)))

(def home-routes
  (context "/:project" [project]
    (if (contains? *dbs* (keyword project))
      (routes
        (GET "/page1" []
          (with-bindings {#'*db* ((keyword project) *dbs*)}
            (serve-page1)))
        (GET "/page2" []
          (with-bindings {#'*db* ((keyword project) *dbs*)}
            (serve-page2))))
      (ANY "*" [] (str "Project not found")))))