const path = require('path')
const fs = require('fs')
const axios = require('axios')
const crypto = require('crypto')
const readline = require('readline')

/**
 * 生成字典插件 v1.0
 * youfool
 */
class constantFile {
  constructor(options) {
    this.options = options
  }
  apply(compiler) {
    compiler.hooks.environment.tap('constantFile', async (compilation, callback) => {
      // 只在开发环境
      if (process.env.ENV === 'development') {
        const projectPath = path.join(__dirname, '../../')
        const constantPath = projectPath + '/src/constant'
        fs.mkdir(constantPath, function (error) {
          if (error) {
            return false
          }
          // 获取字典参数
          axios.get(this.options.api).then((res) => {
            const { code, data } = res.data
            if (code === 0) {
              for (const module of data) {
                // 模块
                const moduleName = Object.keys(module)[0]
                const filePath = constantPath + '/' + moduleName + 'Constant.js'
                let fileStr = templateStr(module[moduleName])
                const hash = crypto.createHash('md5')
                hash.update(fileStr)
                const md5 = hash.digest('hex')
                // 判断之前的文件是否存在
                if (fs.existsSync(filePath)) {
                  const oldFile = readline.createInterface({
                    input: fs.createReadStream(filePath)
                  })
                  let oldMd5
                  oldFile.on('line', function (line) { // 事件监听
                    if (!oldMd5) {
                      // 解析旧文件的字符md5
                      oldMd5 = line.replace('// ', '')
                      if (oldMd5 === md5) {
                        oldFile.close()
                      } else {
                        // 不相同则重新生成常量文件
                        fileStr = `// ${md5}\n` + fileStr
                        fs.writeFileSync(filePath, fileStr, 'utf8')
                      }
                    }
                  })
                } else {
                  // 不相同则重新生成常量文件
                  fileStr = `// ${md5}\n` + fileStr
                  fs.writeFileSync(filePath, fileStr, 'utf8')
                }
              }
            }
          }).catch((e) => { })
        })
      }
    })
  }
}

/**
 * 生成文件字符
 */
function templateStr(dictTypes) {
  const moduleName = dictTypes[0].module
  const moduleDescription = dictTypes[0].moduleDescription
  // 开头
  const head = `/**
  * ${moduleName}${moduleDescription || ''}
  * 注：本文件不能手动修改，需要通过代码生成器生成
  */\n`
  // 底部
  let bottom = 'export default {'
  // 遍历类型
  let content = ''
  for (const dictType of dictTypes) {
    content += `/**
  *${dictType.name}
  *${dictType.typeDescription || ''}
  */`
    for (const dictCode of dictType.dictCodes) {
      const attribute = `${dictType.type.toUpperCase()}_${dictCode.constant.toUpperCase()}`
      content += `\nconst ${attribute} = '${dictCode.code}'// ${dictCode.label}${dictCode.description || ''}`
      bottom += ` ${attribute},`
    }
    content += `\n`
  }
  // 去除最后的逗号
  bottom = bottom.substr(0, bottom.length - 1) + ` }`
  return head + '\n' + content + '\n' + bottom + '\n'
}
module.exports = constantFile