Add new lib for webhook

lib/discord/webhook.ts

@@ -0,0 +1,72 @@
+import {blob} from 'node:stream/consumers'
+import {createReadStream} from 'fs'
+import axios from 'axios'
+import * as core from '@actions/core'
+import {TypedResponse} from '@actions/http-client/lib/interfaces'
+import {HttpClient} from '@actions/http-client'
+
+const client = new HttpClient()
+
+async function handleResponse(response: TypedResponse<unknown>): Promise<void> {
+  core.info(
+    `Webhook returned ${response.statusCode} with message: ${response.result}. Please see discord documentation at https://discord.com/developers/docs/resources/webhook#execute-webhook for more information`
+  )
+  if (response.statusCode >= 400) {
+    core.error(
+      'Discord Webhook Action failed to execute webhook. Please see logs above for details. Error printed below:'
+    )
+    core.error(JSON.stringify(response))
+  }
+}
+
+export async function executeWebhook(
+  webhookUrl: string,
+  threadId: string,
+  filename: string,
+  threadName: string,
+  flags: string,
+  payload: unknown): Promise<void>{
+
+  if (threadId !== '') {
+    webhookUrl = `${webhookUrl}?thread_id=${threadId}`
+  }
+
+  if (filename !== '' || threadName !== '' || flags !== '') {
+    const formData = new FormData()
+    if (filename !== '') {
+      formData.append('upload-file', await blob(createReadStream(filename)))
+      formData.append('payload_json', JSON.stringify(payload))
+    }
+    if (threadName !== '') {
+      formData.append('thread_name', threadName)
+    }
+    if (flags !== '') {
+      formData.append('flags', flags)
+    }
+
+    const response = await axios({
+      method: 'POST',
+      url: webhookUrl,
+      data: formData,
+      headers: {
+        'Content-Type': 'multipart/form-data'
+      }
+    })
+
+    if (response.status !== 200) {
+      if (filename !== '') {
+        core.error(`failed to upload file: ${response.statusText}`)
+      }
+      if (threadName !== '') {
+        core.error(`failed to create thread: ${threadName}`)
+      }
+    } else if (filename !== '') {
+      core.info(
+        `successfully uploaded file with status code: ${response.status}`
+      )
+    }
+  } else {
+    const response = await client.postJson(webhookUrl, payload)
+    await handleResponse(response)
+  }
+}