(ns clojure-sql.core
  (:refer-clojure :exclude [sort])
  (:require [clojure.set :as set]
            [clojure-sql.compiler :as c]
            [clojure-sql.dsl :as d]
            [clojure-sql.query :as q]
            [clojure-sql.util :as u]
            [clojure.walk]))

(def ^:private ^:dynamic *database-type* nil)
(defn set-database-type! [new-type]
  (alter-var-root #'*database-type* (constantly new-type))
  nil)

(def ^:private ^:dynamic *query-executor* nil)
(defn set-query-executor! [exec-fn]
  (alter-var-root #'*query-executor* (constantly exec-fn))
  nil)

(q/set-query-deref-behaviour! #(let [compiled (c/compile *database-type* %)]
                                 (if *query-executor*
                                   (*query-executor* compiled)
                                   compiled)))

(defmethod print-method clojure_sql.query.Query [query writer]
  (binding [*out* writer]
    (pr (c/compile *database-type* query))))


(def table #'d/table)
(def project #'d/project)
(def rename #'d/rename)
(def join #'d/join)
(def select #'d/select)
(def group #'d/group)
(def having #'d/having)
(def sort #'d/sort)

;(def take #'d/take)
;(def drop #'d/drop)


(def insert! (fn [query & records]
               (let [compiled (apply c/insert! *database-type* query records)]
                 (if *query-executor*
                   (*query-executor* compiled)
                   compiled))))

(def update! (fn [query partial-record]
               (let [compiled (c/update! *database-type* query partial-record)]
                 (if *query-executor*
                   (*query-executor* compiled)
                   compiled))))

(def delete! (fn [query]
               (let [compiled (c/delete! *database-type* query)]
                 (if *query-executor*
                   (*query-executor* compiled)
                   compiled))))

(let [users (-> (table :users)
                (project [:id :username :password-hash]))]
  (insert! (-> users
               (project [:username]))
           {:username "john"}
           {:username "not-john"}
           {:username "bleep bloop"}))