feat(notifications): add slack notification agent

re #365

server/lib/notifications/agents/slack.ts

@@ -0,0 +1,225 @@
+import axios from 'axios';
+import { Notification } from '..';
+import logger from '../../../logger';
+import { getSettings, NotificationAgentSlack } from '../../settings';
+import { BaseAgent, NotificationAgent, NotificationPayload } from './agent';
+
+interface EmbedField {
+  type: 'plain_text' | 'mrkdwn';
+  text: string;
+}
+
+interface TextItem {
+  type: 'plain_text' | 'mrkdwn';
+  text: string;
+  emoji?: boolean;
+}
+
+interface Element {
+  type: 'button';
+  text?: TextItem;
+  value: string;
+  url: string;
+  action_id: 'button-action';
+}
+
+interface EmbedBlock {
+  type: 'header' | 'actions' | 'section' | 'context';
+  block_id?: 'section789';
+  text?: TextItem;
+  fields?: EmbedField[];
+  accessory?: {
+    type: 'image';
+    image_url: string;
+    alt_text: string;
+  };
+  elements?: Element[];
+}
+
+interface SlackBlockEmbed {
+  blocks: EmbedBlock[];
+}
+
+class SlackAgent
+  extends BaseAgent<NotificationAgentSlack>
+  implements NotificationAgent {
+  protected getSettings(): NotificationAgentSlack {
+    if (this.settings) {
+      return this.settings;
+    }
+
+    const settings = getSettings();
+
+    return settings.notifications.agents.slack;
+  }
+
+  public buildEmbed(
+    type: Notification,
+    payload: NotificationPayload
+  ): SlackBlockEmbed {
+    const settings = getSettings();
+    let header = 'Overseerr';
+    let actionUrl: string | undefined;
+
+    const fields: EmbedField[] = [];
+
+    switch (type) {
+      case Notification.MEDIA_PENDING:
+        header = 'New Request';
+        fields.push(
+          {
+            type: 'mrkdwn',
+            text: `*Requested By*\n${payload.notifyUser.username ?? ''}`,
+          },
+          {
+            type: 'mrkdwn',
+            text: '*Status*\nPending Approval',
+          }
+        );
+        if (settings.main.applicationUrl) {
+          actionUrl = `${settings.main.applicationUrl}/${payload.media?.mediaType}/${payload.media?.tmdbId}`;
+        }
+        break;
+      case Notification.MEDIA_APPROVED:
+        header = 'Request Approved';
+        fields.push(
+          {
+            type: 'mrkdwn',
+            text: `*Requested By*\n${payload.notifyUser.username ?? ''}`,
+          },
+          {
+            type: 'mrkdwn',
+            text: '*Status*\nProcessing Request',
+          }
+        );
+        if (settings.main.applicationUrl) {
+          actionUrl = `${settings.main.applicationUrl}/${payload.media?.mediaType}/${payload.media?.tmdbId}`;
+        }
+        break;
+      case Notification.MEDIA_AVAILABLE:
+        header = 'Now available!';
+        fields.push(
+          {
+            type: 'mrkdwn',
+            text: `*Requested By*\n${payload.notifyUser.username ?? ''}`,
+          },
+          {
+            type: 'mrkdwn',
+            text: '*Status*\nAvailable',
+          }
+        );
+
+        if (settings.main.applicationUrl) {
+          actionUrl = `${settings.main.applicationUrl}/${payload.media?.mediaType}/${payload.media?.tmdbId}`;
+        }
+        break;
+    }
+
+    const blocks: EmbedBlock[] = [
+      {
+        type: 'header',
+        text: {
+          type: 'plain_text',
+          text: header,
+        },
+      },
+      {
+        type: 'section',
+        text: {
+          type: 'mrkdwn',
+          text: `*${payload.subject}*`,
+        },
+      },
+    ];
+
+    if (payload.message) {
+      blocks.push({
+        type: 'section',
+        text: {
+          type: 'mrkdwn',
+          text: payload.message,
+        },
+        accessory: payload.image
+          ? {
+              type: 'image',
+              image_url: payload.image,
+              alt_text: payload.subject,
+            }
+          : undefined,
+      });
+    }
+
+    if (fields.length > 0) {
+      blocks.push({
+        type: 'section',
+        fields: [
+          ...fields,
+          ...(payload.extra ?? []).map(
+            (extra): EmbedField => ({
+              type: 'mrkdwn',
+              text: `*${extra.name}*\n${extra.value}`,
+            })
+          ),
+        ],
+      });
+    }
+
+    if (actionUrl) {
+      blocks.push({
+        type: 'actions',
+        elements: [
+          {
+            action_id: 'button-action',
+            type: 'button',
+            url: actionUrl,
+            value: 'open_overseerr',
+            text: {
+              type: 'plain_text',
+              text: 'Open Overseerr',
+            },
+          },
+        ],
+      });
+    }
+
+    return {
+      blocks,
+    };
+  }
+
+  // TODO: Add checking for type here once we add notification type filters for agents
+  // eslint-disable-next-line @typescript-eslint/no-unused-vars
+  public shouldSend(_type: Notification): boolean {
+    if (this.getSettings().enabled && this.getSettings().options.webhookUrl) {
+      return true;
+    }
+
+    return false;
+  }
+
+  public async send(
+    type: Notification,
+    payload: NotificationPayload
+  ): Promise<boolean> {
+    logger.debug('Sending slack notification', { label: 'Notifications' });
+    try {
+      const webhookUrl = this.getSettings().options.webhookUrl;
+
+      if (!webhookUrl) {
+        return false;
+      }
+
+      await axios.post(webhookUrl, this.buildEmbed(type, payload));
+
+      return true;
+    } catch (e) {
+      logger.error('Error sending Slack notification', {
+        label: 'Notifications',
+        message: e.message,
+      });
+      return false;
+    }
+  }
+}
+
+export default SlackAgent;