Add basic Emacs email setup

Using msmtp and notmuch.

user/emacs.nix

@@ -10,6 +10,7 @@ in
 {
   imports = [
     nurNoPkgs.repos.rycee.hmModules.emacs-init
+    nurNoPkgs.repos.rycee.hmModules.emacs-notmuch
   ];
 
   nixpkgs.overlays = [ (import sources.emacs-overlay) ];
@@ -387,6 +388,48 @@ in
         command = [ "notifications-notify" ];
       };
 
+      notmuch = {
+        command = [ "notmuch" "notmuch-show-tag" "notmuch-search-tag" ];
+        hook = [
+          ''(notmuch-show . rah-disable-trailing-whitespace-mode)''
+        ];
+        bindLocal = {
+          notmuch-show-mode-map = {
+            "S" = "rah-notmuch-show-tag-spam";
+            "d" = "rah-notmuch-show-tag-deleted";
+          };
+          notmuch-search-mode-map = {
+            "S" = "rah-notmuch-search-tag-spam";
+            "d" = "rah-notmuch-search-tag-deleted";
+          };
+        };
+        config =
+          let
+            listTags = ts: "(list ${toString (map (t: ''"${t}"'') ts)})";
+            spamTags = listTags ["+spam" "-inbox"];
+            deletedTags = listTags ["+deleted" "-inbox"];
+          in
+            ''
+              (defun rah-notmuch-show-tag-spam ()
+                (interactive)
+                (notmuch-show-tag ${spamTags}))
+
+              (defun rah-notmuch-show-tag-deleted ()
+                (interactive)
+                (notmuch-show-tag ${deletedTags}))
+
+              (defun rah-notmuch-search-tag-spam (&optional beg end)
+                (interactive)
+                (notmuch-search-tag ${spamTags} beg end))
+
+              (defun rah-notmuch-search-tag-deleted (&optional beg end)
+                (interactive)
+                (notmuch-search-tag ${deletedTags} beg end))
+
+              (setq notmuch-show-logo nil)
+            '';
+      };
+
       flyspell = {
         enable = true;
         diminish = [ "flyspell-mode" ];
@@ -1404,20 +1447,41 @@ in
       rust-mode.enable = true;
 
       sendmail = {
-        enable = false;
+        command = [ "mail-mode" "mail-text" ];
         mode = [
-          ''("mutt-" . mail-mode)''
-          ''("\\.article" . mail-mode))''
-        ];
-        hook = [
-          ''
-            (lambda ()
-                  (auto-fill-mode)     ; Avoid having to M-q all the time.
-                  (rah-mail-flyspell)  ; I spel funily soemtijms.
-                  (rah-mail-reftex)    ; Make it easy to include references.
-                  (mail-text))         ; Jump to the actual text.
-          ''
+          ''("^mutt-" . mail-mode)''
+          ''("\\.article" . mail-mode)''
         ];
+        bindLocal = {
+          mail-mode-map = {
+            # Make it easy to include references.
+            "C-c [" = "rah-mail-reftex-citation";
+          };
+        };
+        hook = [ "rah-mail-mode-hook" ];
+        config = ''
+          (defun rah-mail-reftex-citation ()
+            (let ((reftex-cite-format 'locally))
+              (reftex-citation)))
+
+          (defun rah-mail-flyspell ()
+            "Enable flyspell and set dictionary based on To: field."
+            (save-excursion
+              (goto-char (point-min))
+              (when (re-search-forward "^To: .*\\.se\\($\\|,\\|>\\)" nil t)
+                (ispell-change-dictionary "swedish"))))
+
+          (defun rah-mail-mode-hook ()
+            (auto-fill-mode)     ; Avoid having to M-q all the time.
+            (rah-mail-flyspell)  ; I spel funily soemtijms.
+            (mail-text))         ; Jump to the actual text.
+
+          (setq sendmail-program "${pkgs.msmtp}/bin/msmtp"
+                send-mail-function 'sendmail-send-it
+                mail-specify-envelope-from t
+                message-sendmail-envelope-from 'header
+                mail-envelope-from 'header)
+        '';
       };
 
       sv-kalender = {