import Worker from 'web-worker';
import fileSaver from 'file-saver'
import { themePlugin } from '@freesewing/plugin-theme'
import { pagesPlugin } from '../layout/print/plugin'
import {utils} from '@freesewing/core'

export const exportTypes = {
  exportForPrinting: ['a4', 'a3', 'a2', 'a1', 'a0', 'letter', 'tabloid'],
  exportForEditing: ['svg', 'pdf'],
  exportAsData: ['json', 'yaml', 'github gist'],
}

export const defaultPdfSettings = {
  size: 'a4',
  orientation: 'portrait',
  margin: 10,
  coverPage: true
}

/**
 * Handle exporting the draft or gist
 * format: format to export to
 * gist: the gist
 * design: the pattern constructor for the design to be exported
 * t: a translation function to attach to the draft
 * app: an app instance
 * onComplete: business to perform after a successful export
 * onError: business to perform on error
 * */
export const handleExport = async(format, gist, design, t, app, onComplete, onError) => {
  // start the loading indicator
  app.startLoading();

  // get a worker going
  const worker = new Worker(new URL('./export-worker.js', import.meta.url), {type: module});

  // listen for the worker's message back
  worker.addEventListener('message', e => {
    // on success
    if (e.data.success) {
      // save it out
      if (e.data.blob) {
        const fileType = exportTypes.exportForPrinting.indexOf(format) === -1 ? format : 'pdf'
        fileSaver.saveAs(e.data.blob, `freesewing-${gist.design || 'gist'}.${fileType}`)
      }
      // do additional business
      onComplete && onComplete(e)
    }
    // on error
    else {
      console.log(e.data.error)
      onError && onError(e)
    }

    // stop the loader
    app.stopLoading()
  })

  let svg = ''
  // pdf settings
  const settings = {
    ...defaultPdfSettings,
    ...(gist._state.layout?.forPrinting?.page || {})
  }

  // arguments to pass to the worker
  const workerArgs = {format, gist, settings}

  // data passed to the worker must be JSON serializable, so we can't pass functions or prototypes
  // that means if it's not a data export there's more work to do before we can hand off to the worker
  if (exportTypes.exportAsData.indexOf(format) === -1) {
    gist.embed=false
    // make a pattern instance for export rendering
    const layout = gist.layouts?.printingLayout || gist.layout || true
    let pattern = new design({...gist, layout})

    // add the theme and translation to the pattern
    pattern.use(themePlugin, {stripped: format !== 'svg'})
    pattern.use({
      hooks: {
        insertText: (locale, text, {t}) => t(text)
      }
    },{t})

    // a specified size should override the gist one
    if (format !== 'pdf') {
      settings.size = format
    }

    try {
      // add pages to pdf exports
      if (format !== 'svg') {
        pattern.use(pagesPlugin({
          ...settings,
          printStyle: true,
          renderBlanks: false,
          setPatternSize: true
        }))

        // add the strings that are used on the cover page
        workerArgs.strings = {
          design: utils.capitalize(gist.design),
          tagline: t('common:sloganCome') + '. ' + t('common:sloganStay'),
          url: window.location.href
        }
      }

      // draft and render the pattern
      pattern.draft();
      svg = pattern.render()

      // add the svg and pages data to the worker args
      workerArgs.svg = svg
      if (pattern.parts.pages) {
        workerArgs.pages = pattern.parts.pages.pages
      }
    } catch(err) {
      console.log(err)
      app.stopLoading();
      onError && onError(err)
    }

  }

  // post a message to the worker with all needed data
  worker.postMessage(workerArgs)
}