import {
  messageSchema,
  MessageMarkdownTransformer,
  MessageMarkdownSerializer,
} from '@chatwoot/prosemirror-schema';
import * as Sentry from '@sentry/browser';

/**
 * The delimiter used to separate the signature from the rest of the body.
 * @type {string}
 */
export const SIGNATURE_DELIMITER = '--';

/**
 * Parse and Serialize the markdown text to remove any extra spaces or new lines
 */
export function cleanSignature(signature) {
  try {
    // remove any horizontal rule tokens
    signature = signature
      .replace(/^( *\* *){3,} *$/gm, '')
      .replace(/^( *- *){3,} *$/gm, '')
      .replace(/^( *_ *){3,} *$/gm, '');

    const nodes = new MessageMarkdownTransformer(messageSchema).parse(
      signature
    );
    return MessageMarkdownSerializer.serialize(nodes);
  } catch (e) {
    // eslint-disable-next-line no-console
    console.warn(e);
    Sentry.captureException(e);
    // The parser can break on some cases
    // for example, Token type `hr` not supported by Markdown parser
    return signature;
  }
}

/**
 * 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
}