Extract search logic and template from messages#index

app/controllers/messages_controller.rb

@@ -3,27 +3,13 @@ class MessagesController < ApplicationController
 
   # GET /messages
   def index
-    query = params[:q]
-    unless query
+    if (query = params[:q])
+      search query
+    else
       @messages = []
-      return
     end
 
-    page = params[:page].to_i
-    list_ids = get_list_ids(params)
-    if list_ids.empty?
-      raise "Need to select at least one list"
-    end
-
-    # %> and <-> are defined by pg_trgm.
-    # https://www.postgresql.org/docs/17/pgtrgm.html
-    message_where = if Rails.env.production?
-      Message.where('body %> ? AND list_id IN (?)', query, list_ids)
-        .order(Arel.sql('body <-> ?', query))
-    else
-      Message.where('body LIKE ? AND list_id IN (?)', "%#{query}%", list_ids)
-    end
-    @messages = message_where.offset(page * PER_PAGE).limit(PER_PAGE)
+    render :search
   end
 
   # GET /messages/1
@@ -37,6 +23,7 @@ def show
   end
 
   private
+
   def get_list_ids(params)
     list_ids = []
     ['ruby-talk', 'ruby-core', 'ruby-list', 'ruby-dev'].each do |name|
@@ -46,4 +33,22 @@ def get_list_ids(params)
     end
     list_ids
   end
+
+  def search(query)
+    page = params[:page].to_i
+    list_ids = get_list_ids(params)
+    if list_ids.empty?
+      raise "Need to select at least one list"
+    end
+
+    # %> and <-> are defined by pg_trgm.
+    # https://www.postgresql.org/docs/17/pgtrgm.html
+    message_where = if Rails.env.production?
+      Message.where('body %> ? AND list_id IN (?)', query, list_ids)
+        .order(Arel.sql('body <-> ?', query))
+    else
+      Message.where('body LIKE ? AND list_id IN (?)', "%#{query}%", list_ids)
+    end
+    @messages = message_where.offset(page * PER_PAGE).limit(PER_PAGE)
+  end
 end