add a new namespace `metabase.email.messages` for collecting functions which...

add a new namespace `metabase.email.messages` for collecting functions which handle templating of stock email messages.  added first function for (send-email-report) which takes appropriate data input and formats an email report message and sends it.

src/metabase/email/messages.clj

+(ns metabase.email.messages
+  "Convenience functions for sending templated email messages.  Each function here should represent a single email.
+   NOTE: we want to keep this about email formatting, so don't put heavy logic here RE: building data for emails."
+  (:require [hiccup.core :refer [html]]
+            [metabase.email :as email]))
+
+
+;;; ### Public Interface
+
+(defn send-email-report
+  "Format and Send an `EmailReport` email."
+  [subject recipients query-result]
+  {:pre [(string? subject)
+         (vector? recipients)
+         (map? query-result)]}
+  (let [html-header-row (fn [cols]
+                          (into [:tr {:style "background-color: #f4f4f4;"}]
+                            (map (fn [col]
+                                   [:td {:style "text-align: left; padding: 0.5em; border: 1px solid #ddd; font-size: 12px;"} col]) cols)))
+        html-data-row (fn [row]
+                        (into [:tr]
+                          (map (fn [cell]
+                                 ;; TODO - format cell
+                                 ;; {{ cell|default_if_none:"N/A"|floatformat:"-2"|default:cell  }}
+                                 [:td {:style "border: 1px solid #ddd; padding: 0.5em;"} cell]) row)))]
+    (email/send-message
+      subject
+      (into {} (map (fn [email] {email email}) recipients))
+      :html (html [:html
+                   [:head]
+                   [:body {:style "font-family: Helvetica Neue, Helvetica, sans-serif; width: 100%; margin: 0 auto; max-width: 800px; font-size: 12px;"}
+                    [:div {:class "wrapper" :style "padding: 10px; background-color: #ffffff;"}
+                     (into [:table {:style "border: 1px solid #cccccc; width: 100%; border-collapse: collapse;"}]
+                       (vector
+                         ;; table header row
+                         (html-header-row (get-in query-result [:data :columns]))
+                         ;; actual data rows
+                         (map (fn [row] (html-data-row row)) (get-in query-result [:data :rows]))))]]]))))