import { Node } from './node'
import { Transformer } from './transformer'
import { unified } from 'unified'
import markdown from 'remark-parse'
import { toString } from 'mdast-util-to-string'
import path from 'path'
import fs from 'fs'

const dirTree = require("directory-tree");

class Util {
  _counter
  cachedSlugMap

  constructor() {
    this._counter = 0
    this.cachedSlugMap = this.getSlugHashMap()
  }

  /**
   * @returns {string | null}
   * */
  // eslint-disable-next-line @typescript-eslint/explicit-function-return-type
  getContent(slug) {
    const currentFilePath = this.toFilePath(slug)
    if (currentFilePath === undefined || currentFilePath == null) return null
    return Node.readFileSync(currentFilePath)
  }

  getShortSummary(slug) {
    const content = this.getContent(slug)
    if (content === undefined || content === null) {
      return
    }

    const tree = unified().use(markdown)
      .parse(content)
    const plainText = toString(tree)
    return plainText.split(' ').splice(0, 40).join(' ')
  }

  getAllMarkdownFiles() {
    return Node.getFiles(Node.getMarkdownFolder())
  }

  getSinglePost(slug) {
    // List of filenames that will provide existing links to wikilink
    const currentFilePath = this.toFilePath(slug)
    // console.log("currentFilePath: ", currentFilePath)

    const fileContent = Node.readFileSync(currentFilePath)

    // const currentFileFrontMatter = Transformer.getFrontMatterData(fileContent)
    // console.log("===============\n\nFile is scanning: ", slug)
    const [htmlContent] = Transformer.getHtmlContent(fileContent)
    // console.log("==================================")
    // console.log("hrmlcontents and backlinks")
    return {
      id: slug,
      // ...currentFileFrontMatter,
      data: htmlContent
    }
  }

  toFilePath(slug) {
    return this.cachedSlugMap[slug]
  }

  getSlugHashMap() {
    // This is to solve problem of converting between slug and filepath,
    // where previously if I convert a slug to a file path sometime
    // it does not always resolve to correct filepath, converting function is not bi-directional
    // and not conflict-free, other solution was considered (hash file name into a hash, but this
    // is not SEO-friendly and make url look ugly ==> I chose this

    const slugMap = new Map()
    this.getAllMarkdownFiles().forEach(aFile => {
      const aSlug = this.toSlug(aFile)
      // if (slugMap.has(aSlug)) {
      //     slugMap[aSlug].push(aFile)
      // } else {
      //     slugMap[aSlug] = [aFile]
      // }
      // Note: [Future improvement] Resolve conflict
      slugMap[aSlug] = aFile
    })

    const indexFile = '/🌎 Home.md'
    slugMap.index = Node.getMarkdownFolder() + indexFile
    slugMap['/'] = Node.getMarkdownFolder() + indexFile

    return slugMap
  }

  toSlug(filePath) {
    const markdownFolder = Node.getMarkdownFolder()
    const isFile = Node.isFile(filePath)
    const isMarkdownFolder = filePath.includes(markdownFolder)

    if (isFile && Boolean(isMarkdownFolder)) {
      return filePath.replace(markdownFolder, '')
        .replaceAll('/', '_')
        .replaceAll(' ', '+')
        .replaceAll('&', '-')
        .replace('.md', '')
    } else {
      // TODO handle this properly
      return '/'
    }
  }

  constructGraphData() {
    const filepath = path.join(process.cwd(), 'graph-data.json')
    if (Node.isFile(filepath)) {
      const data = fs.readFileSync(filepath)
      return JSON.parse(String(data))
    } else {
      const filePaths = this.getAllMarkdownFiles()
      const edges = []
      const nodes = []
      filePaths
        .forEach(aFilePath => {
          // const {currentFilePath} = getFileNames(filename)
          const aNode = {
            title: Transformer.parseFileNameFromPath(aFilePath),
            slug: this.toSlug(aFilePath),
            shortSummary: this.getShortSummary(this.toSlug(aFilePath))
          }
          nodes.push(aNode)

          // console.log("Constructing graph for node: " + aFilePath )
          const internalLinks = Transformer.getInternalLinks(aFilePath)
          internalLinks.forEach(aLink => {
            if (aLink.slug === null || aLink.slug.length === 0) return

            const anEdge = {
              source: this.toSlug(aFilePath),
              target: aLink.slug
            }
            edges.push(anEdge)
            // console.log("Source: " + anEdge.source)
            // console.log("Target: " + anEdge.target)
          })
          // console.log("==============Constructing graph" )
        }
        )
      const data = { nodes, edges }
      fs.writeFileSync(filepath, JSON.stringify(data), 'utf-8')
      return data
    }
  }

  getLocalGraphData(currentNodeId) {
    const { nodes, edges } = constructGraphData()

    const newNodes = nodes.map(aNode => (
      {
        data: {
          id: aNode.slug.toString(),
          label: Transformer.parseFileNameFromPath(this.toFilePath(aNode.slug))
        }
      }
    ))

    const newEdges = edges.map(anEdge => ({
      data: {
        source: anEdge.source,
        target: anEdge.target
      }
    }))

    const existingNodeIDs = newNodes.map(aNode => aNode.data.id)
    currentNodeId = currentNodeId === 'index' ? '__index' : currentNodeId
    if (currentNodeId != null && Boolean(existingNodeIDs.includes(currentNodeId))) {
      const outGoingNodeIds = newEdges
        .filter(anEdge => anEdge.data.source === currentNodeId)
        .map(anEdge => anEdge.data.target)

      const incomingNodeIds = newEdges
        .filter(anEdge => anEdge.data.target === currentNodeId)
        .map(anEdge => anEdge.data.source)

      outGoingNodeIds.push(currentNodeId)

      const localNodeIds = incomingNodeIds.concat(outGoingNodeIds.filter(item => incomingNodeIds.indexOf(item) < 0))
      if (localNodeIds.indexOf(currentNodeId) < 0) {
        localNodeIds.push(currentNodeId)
      }

      const localNodes = newNodes.filter(aNode => localNodeIds.includes(aNode.data.id))
      let localEdges = newEdges.filter(edge => localNodeIds.includes(edge.data.source)).filter(edge => localNodeIds.includes(edge.data.target))

      // Filter self-reference edges
      localEdges = localEdges.filter(edge => edge.data.source !== edge.data.target)

      // TODO: Find out why target ==='/' in some case
      localEdges = localEdges.filter(edge => edge.data.target !== '/')
      return {
        nodes: localNodes,
        edges: localEdges
      }
    } else {
      const filteredEdges = newEdges
        .filter(edge => existingNodeIDs.includes(edge.data.source))
        .filter(edge => existingNodeIDs.includes(edge.data.target))

      return {
        nodes: newNodes,
        edges: filteredEdges
      }
    }
  }

  getAllSlugs() {
    // console.log("\n\nAll Posts are scanning")
    // Get file names under /posts
    const markdownFolder = Node.getMarkdownFolder()
    const markdownFiles = Node.getFiles(markdownFolder)
    const filePaths = markdownFiles.filter(file => !(Boolean(file.endsWith('index')) || Boolean(file.endsWith('sidebar'))))
    return filePaths.map(f => this.toSlug(f))
  }

  getDirectoryData() {
    const filteredDirectory = dirTree(Node.getMarkdownFolder(), { extensions: /\.md/, exclude: [/\.git/, /\.obsidian/] })
    return this.convertObject(filteredDirectory)
  }

  convertObject(thisObject) {
    const children = []
    const slugs = this.getAllSlugs()

    function findFunc(_this, slug) {
      const fileName = Transformer.parseFileNameFromPath(_this.toFilePath(slug))
      return Transformer.normalizeFileName(fileName) === Transformer.normalizeFileName(thisObject.name)
    }

    const foundSlugs = slugs.find(slug => findFunc(this, slug))

    let routerPath = foundSlugs !== (null | undefined) ? foundSlugs : null

    routerPath = routerPath !== (null | undefined) ? '/notes/' + routerPath : null
    const newObject = {
      name: thisObject.name,
      children,
      id: (this._counter++).toString(),
      routePath: routerPath !== (null | undefined) ? routerPath : null
    }

    if (thisObject.children != null && thisObject.children.length > 0) {
      thisObject.children.forEach(aChild => {
        const newChild = this.convertObject(aChild)
        children.push(newChild)
      })
      return newObject
    } else {
      return newObject
    }
  }

  flat = (array) => {
    let result = []
    const outerThis = this
    // eslint-disable-next-line @typescript-eslint/space-before-function-paren
    array.forEach(function(a) {
      result.push(a)
      if (Array.isArray(a.children)) {
        result = result.concat(outerThis.flat(a.children))
      }
    })
    return result
  }

  getFlattenArray(thisObject) {
    return this.flat(thisObject.children)
  }
}

const util = new Util()
export default util