import type { FilterPattern, Plugin, ResolvedConfig } from 'vite'

import MagicString from 'magic-string'
import { createFilter } from 'vite'

interface Options {
  /**
   * @default ["**\/*"]
   */
  include: FilterPattern
  /**
   * @default []
   */
  exclude: FilterPattern
}

type UserOptions = Partial<Options>

type ResolvedOptions = Options
let config: ResolvedConfig = undefined!

const replaceMatched = (code: string, id: string) => {
  const env = config.env
  const source = new MagicString(code, {
    filename: id,
  })

  source.replace(
    /^.*?#if(n?)def\s*(\S+).*[\r\n]{1,2}([\s\S]+?)\s*.*?#endif.*?$/gm,
    /**
     * 条件替换
     * @param _ 匹配的字符串
     * @param $1 是否为 not 模式
     * @param $2 条件
     * @param $3 code
     */
    (_, $1, $2, $3) => {
      const isNot = !!$1
      const isKeep = $2.split('||').some((v: string) => {
        let flag = false
        const [key, value] = v.split('=')
        if (value === undefined)
          flag = !!env[key]

        else
          flag = String(env[key]) === value

        flag = isNot ? !flag : flag
        return flag
      })
      return isKeep ? $3 : ''
    },
  )

  if (source.hasChanged()) {
    return {
      code: source.toString(),
      map: source.generateMap({
        source: id,
        file: `${id}.map`,
        includeContent: true,
      }),
    }
  }
}

const resolveOptions = (userOptions: UserOptions): ResolvedOptions => {
  return {
    include: ['**/*'],
    exclude: [],
    ...userOptions,
  }
}

const VitePluginConditionalCompile = (
  userOptions: UserOptions = {},
): Plugin => {
  const options = resolveOptions(userOptions)
  return {
    name: 'vite-plugin-conditional-compile',
    enforce: 'pre',
    configResolved(_config) {
      config = _config
    },
    transform(code, id) {
      const filter = createFilter(options.include, options.exclude)
      if (filter(id))
        return replaceMatched(code, id)
    },
  }
}

export default VitePluginConditionalCompile