//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 { getAllMarkdownFiles, toFilePath, toSlug } from "./utils";


export class Transformer {

  static haveFrontMatter = (content) => {
    //console.log("\t Front matter data content", content)
    if (!content) return false
    const indexOfFirst = content.indexOf("---");
    //console.log("\t Front matter data firstIndex  ", indexOfFirst)
    //console.log("index first", indexOfFirst)
    if (indexOfFirst === -1) {
      return false
    }
    let 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 = getAllMarkdownFiles()
    const result = allFileNames.find(aFile => {
      let 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) ? [toSlug(result)] : ["/"]
  }

  static hrefTemplate = (permalink) => {
    // permalink = Transformer.normalizeFileName(permalink)
    permalink = permalink.replace("ç", "c").replace("ı", "i").replace("ş", "s")
    return `/note/${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) {
            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('#')) {
            // 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 = toSlug(aFilePath)
            } else {
              canonicalSlug = Transformer.pageResolver(tempSlug)[0].split('#')[0]
            }
          } else {
            canonicalSlug = Transformer.pageResolver(pageName)[0].split('#')[0]
          }

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

          if (canonicalSlug != null && internalLinks.indexOf(canonicalSlug) < 0) {
            internalLinks.push(backLink);
          }

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

        aliasDivider: "|"
      })
      .use(html)
      .processSync(sanitizedContent)

    // console.log("Internal Links of:   "  + aFilePath)
    // internalLinks.forEach(aLink => {
    //     console.log(aLink.title + " --> " + aLink.slug)
    // })
    // console.log("===============Internal Links")
    return internalLinks;
  }
}