use .env and support SMTP configuration

.gitignore

@@ -4,6 +4,9 @@
 .byebug_history
 
 /config/database.yml
+.env
+.env.production
+.env.development
 
 /coverage
 

Gemfile

@@ -5,6 +5,7 @@ source "https://rubygems.org"
 gem "i18n-js", "4.0"
 gem "rails", "~> 6.1"
 gem "rails-i18n", "~> 7.0"
+gem "dotenv-rails", "~> 2.8"
 
 gem "cssbundling-rails", "~> 1.2"
 gem "jsbundling-rails", "~> 1.1"

Gemfile.lock

@@ -130,6 +130,10 @@ GEM
       devise (>= 4.8.0)
     diff-lcs (1.5.0)
     docile (1.4.0)
+    dotenv (2.8.1)
+    dotenv-rails (2.8.1)
+      dotenv (= 2.8.1)
+      railties (>= 3.2)
     dry-core (1.0.0)
       concurrent-ruby (~> 1.0)
       zeitwerk (~> 2.6)
@@ -505,6 +509,7 @@ DEPENDENCIES
   devise (~> 4.9)
   devise-async
   devise-i18n
+  dotenv-rails (~> 2.8)
   dry-initializer (~> 3.1)
   dry-types (~> 1.7)
   factory_bot_rails

config/environments/production.rb

@@ -73,8 +73,40 @@ Rails.application.configure do
   # config.active_job.queue_name_prefix = "justask_#{Rails.env}"
   config.action_mailer.perform_caching = false
 
-  # Use sendmail
-  config.action_mailer.delivery_method = :sendmail
+  config.action_mailer.default_options[:reply_to] = ENV['SMTP_REPLY_TO'] if ENV['SMTP_REPLY_TO'].present?
+  config.action_mailer.default_options[:return_path] = ENV['SMTP_RETURN_PATH'] if ENV['SMTP_RETURN_PATH'].present?
+
+  enable_starttls = nil
+  enable_starttls_auto = nil
+
+  case ENV['SMTP_ENABLE_STARTTLS']
+  when 'always'
+    enable_starttls = true
+  when 'never'
+    enable_starttls = false
+  when 'auto'
+    enable_starttls_auto = true
+  else
+    enable_starttls_auto = ENV['SMTP_ENABLE_STARTTLS_AUTO'] != 'false'
+  end
+
+  config.action_mailer.smtp_settings = {
+    port: ENV['SMTP_PORT'],
+    address: ENV['SMTP_SERVER'],
+    user_name: ENV['SMTP_LOGIN'].presence,
+    password: ENV['SMTP_PASSWORD'].presence,
+    domain: ENV['SMTP_DOMAIN'] || ENV['LOCAL_DOMAIN'],
+    authentication: ENV['SMTP_AUTH_METHOD'] == 'none' ? nil : ENV['SMTP_AUTH_METHOD'] || :plain,
+    ca_file: ENV['SMTP_CA_FILE'].presence || '/etc/ssl/certs/ca-certificates.crt',
+    openssl_verify_mode: ENV['SMTP_OPENSSL_VERIFY_MODE'],
+    enable_starttls: enable_starttls,
+    enable_starttls_auto: enable_starttls_auto,
+    tls: ENV['SMTP_TLS'].presence && ENV['SMTP_TLS'] == 'true',
+    ssl: ENV['SMTP_SSL'].presence && ENV['SMTP_SSL'] == 'true',
+    read_timeout: 20,
+  }
+
+  config.action_mailer.delivery_method = ENV.fetch('SMTP_DELIVERY_METHOD', 'sendmail').to_sym
 
   # Ignore bad email addresses and do not raise email delivery errors.
   # Set this to true and configure the email server for immediate delivery to raise delivery errors.