(ns blog.db
  (:require ["pg" :refer [Client]]
            [cljs.core.async :refer [go, take!, put!, >!, chan]]
            [cljs.core.async.interop :refer-macros [<p!]]
            [cljs.core :refer [clj->js js->clj]]
            [blog.env :as env]))

(defn create-client
  "Create a new client for Postgres using enviroment variables."
  []
  (->> (env/get-database-credentials)
       (cljs.core/clj->js)
       (new Client)))

(defn connect-client
  "Connect a client to the database"
  [client]
  (. client connect))

(defn create-tables
  [client]
  (. client query "CREATE TABLE IF NOT EXISTS articles (id SERIAL PRIMARY KEY, title VARCHAR(255) NOT NULL, content TEXT NOT NULL, created TIMESTAMP DEFAULT CURRENT_TIMESTAMP);"))

(defn get-articles
  "Reads all articles and returns via channel. It gets and returns the same channel."
  [client channel]
  (go
    (try
      (let [res (<p! (. client query "select * from articles"))]
        (>! channel (.-rows res)))
      (catch js/Error err (js/console.log (ex-cause err)))))
  channel)

(defn get-article
  "Reads an article with the id and returns via channel. It gets and returns the same channel. Empty collection if not found."
  [client id channel]
  (go
    (try
      (let [res (<p! (.query client
                             "select * from articles where id=$1"
                             (clj->js [id])))]
        (>! channel (-> (.-rows res)
                        (js->clj :keywordize-keys true)
                        (first))))
      (catch js/Error err (js/console.log (ex-cause err)))))
  channel)