Improve the way messages are sent

We want the proper encoding and content-type to be set when sending the
mail, but human-readable plain-text for composing. So split the code in
two parts: the presentation and the transport conversion.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>

plugin/notmuch.vim

@@ -86,17 +86,22 @@ endfunction
 function! s:compose_send()
 	let b:compose_done = 1
 	let fname = expand('%')
+	let lines = getline(5, '$')
 
-	" remove headers
-	0,4d
-	write
+ruby << EOF
+	# Generate proper mail to send
+	text = VIM::evaluate('lines').join("\n")
+	fname = VIM::evaluate('fname')
+	transport = Mail.new(text)
+	transport.message_id = generate_message_id
+	transport.charset = 'utf-8'
+	File.write(fname, transport.to_s)
+EOF
 
 	let cmdtxt = g:notmuch_sendmail . ' -t -f ' . s:reply_from . ' < ' . fname
 	let out = system(cmdtxt)
 	let err = v:shell_error
 	if err
-		undo
-		write
 		echohl Error
 		echo 'Eeek! unable to send mail'
 		echo out
@@ -572,9 +577,7 @@ ruby << EOF
 			end
 			m.cc = orig[:cc]
 			m.from = $email
-			m.message_id = generate_message_id
 			m.charset = 'utf-8'
-			m.content_transfer_encoding = '7bit'
 		end
 
 		lines = []
@@ -600,7 +603,7 @@ ruby << EOF
 
 		reply.body = body_lines.join("\n")
 
-		lines += reply.to_s.lines.map { |e| e.chomp }
+		lines += reply.present.lines.map { |e| e.chomp }
 		lines << ""
 
 		cur = lines.count - 1
@@ -611,18 +614,13 @@ ruby << EOF
 	def open_compose()
 		lines = []
 
-		lines << "Date: #{Time.now().strftime('%a, %-d %b %Y %T %z')}"
 		lines << "From: #{$email}"
 		lines << "To: "
 		cur = lines.count
 
 		lines << "Cc: "
 		lines << "Bcc: "
-		lines << "Message-Id: #{generate_message_id}"
 		lines << "Subject: "
-		lines << "Mime-Version: 1.0"
-		lines << "Content-Type: text/plain; charset=utf-8"
-		lines << "Content-Transfer-Encoding: 7bit"
 		lines << ""
 		lines << ""
 		lines << ""
@@ -928,6 +926,16 @@ ruby << EOF
 				end
 				text
 			end
+
+			def present
+				buffer = ''
+				header.fields.each do |f|
+					buffer << "%s: %s\r\n" % [f.name, f.to_s]
+				end
+				buffer << "\r\n"
+				buffer << body.to_s
+				buffer
+			end
 		end
 	end