// import matter from 'gray-matter'
import { unified } from 'unified'
import markdown from 'remark-parse'
import { wikiLinkPlugin } from 'remark-wiki-link'
import html from 'remark-html'
// import frontmatter from "remark-frontmatter";
import externalLinks from 'remark-external-links'
import highlight from 'remark-highlight.js'
import { Node } from './node'
import rehypePrism from 'rehype-prism-plus'
import remarkRehype from 'remark-rehype'
import rehypeStringify from 'rehype-stringify'
import obsidianImage from './obsidian-image.js'
import Utils from '../lib/utils.js'

export class Transformer {
  static haveFrontMatter = (content) => {
    // console.log("\t Front matter data content", content)
    if (content === (null | undefined | '')) return false
    const indexOfFirst = content.indexOf('---')
    // console.log("\t Front matter data firstIndex  ", indexOfFirst)
    // console.log("index first", indexOfFirst)
    if (indexOfFirst === -1) {
      return false
    }
    const indexOfSecond = content.indexOf('---', (indexOfFirst + 1))
    return indexOfSecond !== -1
  }

  static getFrontMatterData = (filecontent) => {
    // if (Transformer.haveFrontMatter(filecontent)) {
    // return matter(filecontent).data
    // }
    return {}
  }

  static pageResolver = (pageName) => {
    const allFileNames = Utils.getAllMarkdownFiles()
    const result = allFileNames.find(aFile => {
      const parseFileNameFromPath = Transformer.parseFileNameFromPath(aFile)
      return Transformer.normalizeFileName(parseFileNameFromPath) === Transformer.normalizeFileName(pageName)
    }
    )

    // permalink = permalink.replace("ç", "c").replace("ı", "i").replace("ş", "s")
    // console.log(`/note/${toSlug(result)}`)
    if (result === undefined || result.length === 0) {
      // console.log("Cannot resolve file path   " + pageName)
    }

    // console.log("Internal Link resolved:   [" + pageName + "] ==> [" + temp[0] +"]")
    return (result !== undefined && result.length > 0) ? [Utils.toSlug(result)] : ['/']
  }

  static hrefTemplate = (permalink) => {
    // permalink = Transformer.normalizeFileName(permalink)
    permalink = permalink.replace('ç', 'c').replace('ı', 'i').replace('ş', 's')
    return `/notes/${permalink}`
  }

  static getHtmlContent = (content) => {
    let htmlContent = []
    const sanitizedContent = Transformer.preprocessThreeDashes(content)

    unified()
      .use(markdown, { gfm: true })
      .use(obsidianImage)
      .use(highlight)
      .use(externalLinks, { target: '_blank', rel: ['noopener'] })
      // .use(frontmatter, ['yaml', 'toml'])
      .use(wikiLinkPlugin, {
        permalinks: null,
        pageResolver: (pageName) => {
          return Transformer.pageResolver(pageName)
        },
        hrefTemplate: (permalink) => {
          return Transformer.hrefTemplate(permalink)
        },

        aliasDivider: '|'
      })
      .use(remarkRehype)
      .use(rehypePrism)
      .use(rehypeStringify)
      .process(sanitizedContent,
        function(err, file) {
          htmlContent.push(String(file).replace('\n', ''))
          if (err !== (null | undefined)) {
            console.log('ERRROR:' + err)
          }
        }
      )
    htmlContent = htmlContent.join('')
    htmlContent = htmlContent.split('---')
    return [htmlContent]
  }

  /* SANITIZE MARKDOWN FOR --- */
  static preprocessThreeDashes = (content) => {
    const indexOfFirst = content.indexOf('---')
    if (indexOfFirst === -1) {
      return content
    }
    const indexOfSecond = content.indexOf('---', (indexOfFirst + 1))
    content.slice(0, indexOfSecond)
    const contentPart = content.slice(indexOfSecond)
    return contentPart.split('---').join('')
  }

  /* Normalize File Names */
  static normalizeFileName = (filename) => {
    let processedFileName = filename.replace('.md', '')
    processedFileName = processedFileName.replace('(', '').replace(')', '')
    processedFileName = processedFileName.split(' ').join('-')
    processedFileName = processedFileName.toLowerCase()
    const conversionLetters = [
      ['ç', 'c'], ['ş', 's'], ['ı', 'i'], ['ü', 'u'], ['ö', 'o'], ['ğ', 'g'],
      ['Ç', 'C'], ['Ş', 'S'], ['İ', 'I'], ['Ü', 'U'], ['Ö', 'O'], ['Ğ', 'G']

    ]
    conversionLetters.forEach(letterPair => {
      processedFileName = processedFileName.split(letterPair[0]).join(letterPair[1])
      // processedFileName = processedFileName.replace(letterPair[0], letterPair[1])
    }
    )
    // console.log("filename", processedFileName)
    return processedFileName
  }

  /* Parse file name from path then sanitize it */
  static parseFileNameFromPath = (filepath) => {
    if (typeof filepath === 'string' && filepath.includes('/')) {
      const parsedFileFromPath = filepath.split('/')[filepath.split('/').length - 1]
      return parsedFileFromPath.replace('.md', '')
    } else {
      console.log('Failed: CANNOT Parse' + filepath)
      return null
    }
  }

  /* Pair provided and existing Filenames */
  static getInternalLinks = (aFilePath) => {
    const fileContent = Node.readFileSync(aFilePath)
    const internalLinks = []
    const sanitizedContent = Transformer.preprocessThreeDashes(fileContent)
    unified()
      .use(markdown, { gfm: true })
      .use(wikiLinkPlugin, {
        pageResolver: function(pageName) {
          // let name = [Transformer.parseFileNameFromPath(pageName)];

          let canonicalSlug
          if (pageName.includes('#') !== (false, null, undefined)) {
            // console.log(pageName)
            const tempSlug = pageName.split('#')[0]
            if (tempSlug.length === 0) {
              // Meaning it in form of #Heading1 --> slug will be this file slug
              canonicalSlug = Utils.toSlug(aFilePath)
            } else {
              canonicalSlug = Transformer.pageResolver(tempSlug)[0].split('#')[0]
            }
          } else {
            canonicalSlug = Transformer.pageResolver(pageName)[0].split('#')[0]
          }

          const backLink = {
            title: Transformer.parseFileNameFromPath(Utils.toFilePath(canonicalSlug)),
            slug: canonicalSlug,
            shortSummary: canonicalSlug
          }

          if (canonicalSlug != null && !internalLinks.includes(canonicalSlug)) {
            internalLinks.push(backLink)
          }

          return [canonicalSlug]
        },
        hrefTemplate: (permalink) => {
          return Transformer.hrefTemplate(permalink)
        },

        aliasDivider: '|'
      })
      .use(html)
      .processSync(sanitizedContent)
    return internalLinks
  }
}