/*
Copyright (C) 2020  Cloudbase Solutions SRL
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as
published by the Free Software Foundation, either version 3 of the
License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

import JSZip from 'jszip'

export type FileContent = {
  name: string,
  content: string,
}

class FileUtils {
  static async readFile(file: File): Promise<FileContent> {
    const reader = new FileReader()

    return new Promise((resolve, reject) => {
      reader.onload = e => {
        const content: any = e.target?.result
        resolve({ name: file.name, content })
      }
      reader.onerror = e => { reject(e) }
      reader.readAsText(file)
    })
  }

  static async readContentFromFileList(fileList: FileList | null): Promise<FileContent[]> {
    if (!fileList || !fileList.length) {
      return []
    }
    const result: FileContent[] = []
    await Promise.all(Array.from(fileList).map(async file => {
      if (file.name.substr(file.name.length - 4) === '.zip') {
        const zip = await JSZip.loadAsync(file)
        await Promise.all(Object.keys(zip.files).map(async zipFileName => {
          if (zipFileName.indexOf('__MACOSX') === 0) {
            return
          }
          const zipContent = await zip.files[zipFileName].async('string')
          result.push({ name: zipFileName, content: zipContent })
        }))
      } else {
        const fileContent = await this.readFile(file)
        result.push(fileContent)
      }
    }))
    return result
  }

  static readTextFromFirstFile(fileList: FileList): Promise<string | null> {
    if (!fileList.length) {
      return Promise.resolve(null)
    }
    const file = fileList[0]
    const reader = new FileReader()
    return new Promise((resolve, reject) => {
      reader.onload = e => {
        const content: any = e.target?.result
        resolve(content)
      }
      reader.onerror = e => { reject(e) }
      reader.readAsText(file)
    })
  }
}

export default FileUtils