const _ = require('lodash')
const keygen = require('browser/lib/keygen')
const resolveStorageData = require('./resolveStorageData')
const consts = require('browser/lib/consts')
const CSON = require('@rokt33r/season')
const path = require('path')
const sander = require('sander')

function migrateFromV5Storage (storageKey, data) {
  let targetStorage
  try {
    const cachedStorageList = JSON.parse(localStorage.getItem('storages'))
    if (!_.isArray(cachedStorageList)) throw new Error('Target storage doesn\'t exist.')

    targetStorage = _.find(cachedStorageList, {key: storageKey})
    if (targetStorage == null) throw new Error('Target storage doesn\'t exist.')
  } catch (e) {
    return Promise.reject(e)
  }
  return resolveStorageData(targetStorage)
    .then(function (storage) {
      return importAll(storage, data)
    })
}

function importAll (storage, data) {
  const oldArticles = data.articles
  const notes = []
  data.folders
    .forEach(function (oldFolder) {
      let folderKey = keygen()
      while (storage.folders.some((folder) => folder.key === folderKey)) {
        folderKey = keygen()
      }
      const newFolder = {
        key: folderKey,
        name: oldFolder.name,
        color: consts.FOLDER_COLORS[Math.floor(Math.random() * 7) % 7]
      }

      storage.folders.push(newFolder)

      const articles = oldArticles.filter((article) => article.FolderKey === oldFolder.key)
      articles.forEach((article) => {
        let noteKey = keygen()
        let isUnique = false
        while (!isUnique) {
          try {
            sander.statSync(path.join(storage.path, 'notes', noteKey + '.cson'))
            noteKey = keygen()
          } catch (err) {
            if (err.code === 'ENOENT') {
              isUnique = true
            } else {
              console.error('Failed to read `notes` directory.')
              throw err
            }
          }
        }

        if (article.mode === 'markdown') {
          const newNote = {
            tags: article.tags,
            createdAt: article.createdAt,
            updatedAt: article.updatedAt,
            folder: folderKey,
            storage: storage.key,
            type: 'MARKDOWN_NOTE',
            isStarred: false,
            title: article.title,
            content: '# ' + article.title + '\n\n' + article.content,
            key: noteKey,
            linesHighlighted: article.linesHighlighted
          }
          notes.push(newNote)
        } else {
          const newNote = {
            tags: article.tags,
            createdAt: article.createdAt,
            updatedAt: article.updatedAt,
            folder: folderKey,
            storage: storage.key,
            type: 'SNIPPET_NOTE',
            isStarred: false,
            title: article.title,
            description: article.title,
            key: noteKey,
            snippets: [{
              name: article.mode,
              mode: article.mode,
              content: article.content,
              linesHighlighted: article.linesHighlighted
            }]
          }
          notes.push(newNote)
        }
      })
    })

  notes.forEach(function (note) {
    CSON.writeFileSync(path.join(storage.path, 'notes', note.key + '.cson'), _.omit(note, ['storage', 'key']))
  })

  CSON.writeFileSync(path.join(storage.path, 'boostnote.json'), _.pick(storage, ['version', 'folders']))

  return {
    storage,
    notes
  }
}

module.exports = migrateFromV5Storage