feat: Allow signature in the editor directly (#7881)

Co-authored-by: Sivin Varghese <64252451+iamsivin@users.noreply.github.com>
Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>

app/javascript/dashboard/helper/editorHelper.js

@@ -0,0 +1,135 @@
+/**
+ * The delimiter used to separate the signature from the rest of the body.
+ * @type {string}
+ */
+export const SIGNATURE_DELIMITER = '--';
+
+/**
+ * Trim the signature and remove all " \r" from the signature
+ * 1. Trim any extra lines or spaces at the start or end of the string
+ * 2. Converts all \r or \r\n to \f
+ */
+export function cleanSignature(signature) {
+  return signature.trim().replace(/\r\n?/g, '\n');
+}
+
+/**
+ * Adds the signature delimiter to the beginning of the signature.
+ *
+ * @param {string} signature - The signature to add the delimiter to.
+ * @returns {string} - The signature with the delimiter added.
+ */
+function appendDelimiter(signature) {
+  return `${SIGNATURE_DELIMITER}\n\n${cleanSignature(signature)}`;
+}
+
+/**
+ * Check if there's an unedited signature at the end of the body
+ * If there is, return the index of the signature, If there isn't, return -1
+ *
+ * @param {string} body - The body to search for the signature.
+ * @param {string} signature - The signature to search for.
+ * @returns {number} - The index of the last occurrence of the signature in the body, or -1 if not found.
+ */
+export function findSignatureInBody(body, signature) {
+  const trimmedBody = body.trimEnd();
+  const cleanedSignature = cleanSignature(signature);
+
+  // check if body ends with signature
+  if (trimmedBody.endsWith(cleanedSignature)) {
+    return body.lastIndexOf(cleanedSignature);
+  }
+
+  return -1;
+}
+
+/**
+ * Appends the signature to the body, separated by the signature delimiter.
+ *
+ * @param {string} body - The body to append the signature to.
+ * @param {string} signature - The signature to append.
+ * @returns {string} - The body with the signature appended.
+ */
+export function appendSignature(body, signature) {
+  const cleanedSignature = cleanSignature(signature);
+  // if signature is already present, return body
+  if (findSignatureInBody(body, cleanedSignature) > -1) {
+    return body;
+  }
+
+  return `${body.trimEnd()}\n\n${appendDelimiter(cleanedSignature)}`;
+}
+
+/**
+ * Removes the signature from the body, along with the signature delimiter.
+ *
+ * @param {string} body - The body to remove the signature from.
+ * @param {string} signature - The signature to remove.
+ * @returns {string} - The body with the signature removed.
+ */
+export function removeSignature(body, signature) {
+  // this will find the index of the signature if it exists
+  // Regardless of extra spaces or new lines after the signature, the index will be the same if present
+  const cleanedSignature = cleanSignature(signature);
+  const signatureIndex = findSignatureInBody(body, cleanedSignature);
+
+  // no need to trim the ends here, because it will simply be removed in the next method
+  let newBody = body;
+
+  // if signature is present, remove it and trim it
+  // trimming will ensure any spaces or new lines before the signature are removed
+  // This means we will have the delimiter at the end
+  if (signatureIndex > -1) {
+    newBody = newBody.substring(0, signatureIndex).trimEnd();
+  }
+
+  // let's find the delimiter and remove it
+  const delimiterIndex = newBody.lastIndexOf(SIGNATURE_DELIMITER);
+  if (
+    delimiterIndex !== -1 &&
+    delimiterIndex === newBody.length - SIGNATURE_DELIMITER.length // this will ensure the delimiter is at the end
+  ) {
+    // if the delimiter is at the end, remove it
+    newBody = newBody.substring(0, delimiterIndex);
+  }
+
+  // return the value
+  return newBody;
+}
+
+/**
+ * Replaces the old signature with the new signature.
+ * If the old signature is not present, it will append the new signature.
+ *
+ * @param {string} body - The body to replace the signature in.
+ * @param {string} oldSignature - The signature to replace.
+ * @param {string} newSignature - The signature to replace the old signature with.
+ * @returns {string} - The body with the old signature replaced with the new signature.
+ *
+ */
+export function replaceSignature(body, oldSignature, newSignature) {
+  const withoutSignature = removeSignature(body, oldSignature);
+  return appendSignature(withoutSignature, newSignature);
+}
+
+/**
+ * Extract text from markdown, and remove all images, code blocks, links, headers, bold, italic, lists etc.
+ * Links will be converted to text, and not removed.
+ *
+ * @param {string} markdown - markdown text to be extracted
+ * @returns
+ */
+export function extractTextFromMarkdown(markdown) {
+  return markdown
+    .replace(/```[\s\S]*?```/g, '') // Remove code blocks
+    .replace(/`.*?`/g, '') // Remove inline code
+    .replace(/!\[.*?\]\(.*?\)/g, '') // Remove images before removing links
+    .replace(/\[([^\]]+)\]\([^)]+\)/g, '$1') // Remove links but keep the text
+    .replace(/#+\s*|[*_-]{1,3}/g, '') // Remove headers, bold, italic, lists etc.
+    .split('\n')
+    .map(line => line.trim())
+    .filter(Boolean)
+    .join('\n') // Trim each line & remove any lines only having spaces
+    .replace(/\n{2,}/g, '\n') // Remove multiple consecutive newlines (blank lines)
+    .trim(); // Trim any extra space
+}