DEV: Adds post_to_slack scriptable for automation (#108)

This allows for the discourse automation plugin to have a "Send Slack
Message" script.

The script fields are a message, url, and slack channel. This will allow
for a custom slack message to be posted but can link back to an
arbitrary url (hopefully a discourse url) like a list of unanswered
topics instead of strictly only allowing a slack message that links back
to a Discourse Post object.

config/locales/client.en.yml

@@ -236,3 +236,14 @@ en:
             webhook_url:
               title: "Webhook URL"
               help: "The URL provided when you create a new webhook"
+    discourse_automation:
+      scriptables:
+        send_slack_message:
+          title: Send Slack message
+          fields:
+            message:
+              label: Message
+            url:
+              label: URL
+            channel:
+              label: Channel

config/locales/server.en.yml

@@ -104,6 +104,10 @@ en:
     chat_integration_google_enabled: "Enable the 'Google Chat' chat integration provider"
     chat_integration_google_excerpt_length: "Google Chat post excerpt length"
 
+  discourse_automation:
+    scriptables:
+      send_slack_message:
+        title: Send Slack message
   chat_integration:
 
     all_categories: "(all categories)"

lib/discourse_chat_integration/provider/slack/slack_provider.rb

@@ -106,12 +106,15 @@ module DiscourseChatIntegration::Provider::SlackProvider
       channel: message[:channel].gsub('#', ''),
       attachments: message[:attachments].to_json
     }
+
+    if post
       if message.key?(:thread_ts)
         data[:thread_ts] = message[:thread_ts]
       elsif (match = slack_thread_regex.match(post.raw)) && match.captures[0] == channel
         data[:thread_ts] = match.captures[1]
         set_slack_thread_ts(post.topic, channel, match.captures[1])
       end
+    end
 
     req.set_form_data(data)
 
@@ -133,7 +136,7 @@ module DiscourseChatIntegration::Provider::SlackProvider
     end
 
     ts = json["ts"]
-    set_slack_thread_ts(post.topic, channel, ts) if !ts.nil?
+    set_slack_thread_ts(post.topic, channel, ts) if !ts.nil? && !post.nil?
 
     response
   end

plugin.rb

@@ -40,4 +40,62 @@ after_initialize do
   end
 
   DiscourseChatIntegration::Provider.mount_engines
+
+  if defined?(DiscourseAutomation)
+    add_automation_scriptable('send_slack_message') do
+      field :message, component: :message, required: true, accepts_placeholders: true
+      field :url, component: :text, required: true
+      field :channel, component: :text, required: true
+
+      version 1
+
+      triggerables %i[point_in_time recurring]
+
+      script do |context, fields, automation|
+        sender = Discourse.system_user
+
+        content = fields.dig('message', 'value')
+        url = fields.dig('url', 'value')
+        full_content = "#{content} - #{url}"
+        channel_name = fields.dig('channel', 'value')
+        channel = DiscourseChatIntegration::Channel.new(provider: "slack", data: { identifier: "##{channel_name}" })
+
+        icon_url =
+          if SiteSetting.chat_integration_slack_icon_url.present?
+            "#{Discourse.base_url}#{SiteSetting.chat_integration_slack_icon_url}"
+          elsif (url = (SiteSetting.try(:site_logo_small_url) || SiteSetting.logo_small_url)).present?
+            "#{Discourse.base_url}#{url}"
+          end
+
+        slack_username =
+          if SiteSetting.chat_integration_slack_username.present?
+            SiteSetting.chat_integration_slack_username
+          else
+            SiteSetting.title || "Discourse"
+          end
+
+        message = {
+          channel: "##{channel_name}",
+          username: slack_username,
+          icon_url: icon_url,
+          attachments: []
+        }
+
+        summary = {
+          fallback: content.truncate(100),
+          author_name: sender,
+          color: nil,
+          text: full_content,
+          mrkdwn_in: ["text"],
+          title: content.truncate(100),
+          title_link: url,
+          thumb_url: nil
+        }
+
+        message[:attachments].push(summary)
+
+        DiscourseChatIntegration::Provider::SlackProvider.send_via_api(nil, channel, message)
+      end
+    end
+  end
 end