import path from 'path'
import globby from 'globby'
import isGlob from 'is-glob'
import globParent from 'glob-parent'
import normalizePath from 'normalize-path'

const isDirectory = filePath => path.extname(filePath).length === 0

export const glob = async (
  patterns: Array<string>,
  options: {}
): Promise<Array<string>> => globby(patterns, options)

export const ensureGlob = (
  entry: string,
  recursive: boolean = false,
  pattern: string = '*.js'
): string => {
  const normalized = normalizePath(entry)

  if (isGlob(normalized)) {
    return normalized
  } if (isDirectory(normalized)) {
    if (!isGlob(pattern)) {
      throw new Error(`Provided Glob ${pattern} is not a valid glob pattern`)
    }

    const parent = globParent(pattern)
    if (parent !== '.' || pattern.indexOf('**') !== -1) {
      throw new Error(
        `Provided Glob ${pattern} must be a file pattern like *.js`
      )
    }

    const globstar = recursive ? '**/' : ''

    return `${normalized}/${globstar}${pattern}`
  }
  return normalized
}

export const extensionsToGlob = (extensions: Array<string>) => {
  const filtered = extensions.filter(Boolean)

  if (filtered.length === 0) {
    return '*.js'
  } if (filtered.length === 1) {
    return `*${filtered[0]}`
  }
  return `*{${filtered.join(',')}}`
}