text: const arrify = require('arrify')
  const fs = require('fs')
  const path = require('path')
  const findUp = require('find-up')
  const testExclude = require('test-exclude')
  const Yargs = require('yargs/yargs')
  
  var Config = {}
  
  // load config from a cascade of sources:
  // * command line arguments
  // * package.json
  // * .nycrc
  Config.loadConfig = function (argv, cwd) {
    cwd = cwd || process.env.NYC_CWD || process.cwd()
    var pkgPath = findUp.sync('package.json', {cwd: cwd})
    var rcPath = findUp.sync(['.nycrc', '.nycrc.json'], {cwd: cwd})
    var rcConfig = null
  
    if (rcPath) {
      rcConfig = JSON.parse(
        fs.readFileSync(rcPath, 'utf-8')
      )
    }
  
    if (pkgPath) {
      cwd = path.dirname(pkgPath)
    }
  
    var config = Config.buildYargs(cwd)
      .default({
        cwd: cwd
      })
    if (rcConfig) config.config(rcConfig)
    config = config.parse(argv || [])
  
    // post-hoc, we convert several of the
    // configuration settings to arrays, providing
    // a consistent contract to index.js.
    config.require = arrify(config.require)
    config.extension = arrify(config.extension)
    config.exclude = arrify(config.exclude)
    config.include = arrify(config.include)
    config.cwd = cwd
  
    return config
  }
  
  // build a yargs object, omitting any settings
  // that would cause the application to exit early.
  Config.buildYargs = function (cwd) {
    return Yargs([])
      .usage('$0 [command] [options]\n\nrun your tests with the nyc bin to instrument them with coverage')
      .command('report', 'run coverage report for .nyc_output', function (yargs) {
        return yargs
          .usage('$0 report [options]')
          .option('reporter', {
            alias: 'r',
            describe: 'coverage reporter(s) to use',
            default: 'text'
          })
          .option('report-dir', {
            describe: 'directory to output coverage reports in',
            default: 'coverage'
          })
          .option('temp-directory', {
            describe: 'directory to read raw coverage information from',
            default: './.nyc_output'
          })
          .option('show-process-tree', {
            describe: 'display the tree of spawned processes',
            default: false,
            type: 'boolean'
          })
          .example('$0 report --reporter=lcov', 'output an HTML lcov report to ./coverage')
      })
      .command('check-coverage', 'check whether coverage is within thresholds provided', function (yargs) {
        return yargs
          .usage('$0 check-coverage [options]')
          .option('branches', {
            default: 0,
            description: 'what % of branches must be covered?'
          })
          .option('functions', {
            default: 0,
            description: 'what % of functions must be covered?'
          })
          .option('lines', {
            default: 90,
            description: 'what % of lines must be covered?'
          })
          .option('statements', {
            default: 0,
            description: 'what % of statements must be covered?'
          })
          .option('per-file', {
            default: false,
            description: 'check thresholds per file'
          })
          .example('$0 check-coverage --lines 95', "check whether the JSON in nyc's output folder meets the thresholds provided")
      })
      .option('reporter', {
        alias: 'r',
        describe: 'coverage reporter(s) to use',
        default: 'text',
        globa: false
      })
      .option('report-dir', {
        describe: 'directory to output coverage reports in',
        default: 'coverage',
        global: false
      })
      .option('silent', {
        alias: 's',
        default: false,
        type: 'boolean',
        describe: "don't output a report after tests finish running",
        global: false
      })
      .option('all', {
        alias: 'a',
        default: false,
        type: 'boolean',
        describe: 'whether or not to instrument all files of the project (not just the ones touched by your test suite)',
        global: false
      })
      .option('exclude', {
        alias: 'x',
        default: testExclude.defaultExclude,
        describe: 'a list of specific files and directories that should be excluded from coverage, glob patterns are supported, node_modules is always excluded',
        global: false
      })
      .option('include', {
        alias: 'n',
        default: [],
        describe: 'a list of specific files that should be covered, glob patterns are supported',
        global: false
      })
      .option('require', {
        alias: 'i',
        default: [],
        describe: 'a list of additional modules that nyc should attempt to require in its subprocess, e.g., babel-register, babel-polyfill.',
        global: false
      })
      .option('eager', {
        default: false,
        type: 'boolean',
        describe: 'instantiate the instrumenter at startup (see https://git.io/vMKZ9)',
        global: false
      })
      .option('cache', {
        alias: 'c',
        default: true,
        type: 'boolean',
        describe: 'cache instrumentation results for improved performance',
        global: false
      })
      .option('babel-cache', {
        default: false,
        type: 'boolean',
        describe: 'cache babel transpilation results for improved performance',
        global: false
      })
      .option('extension', {
        alias: 'e',
        default: [],
        describe: 'a list of extensions that nyc should handle in addition to .js',
        global: false
      })
      .option('check-coverage', {
        type: 'boolean',
        default: false,
        describe: 'check whether coverage is within thresholds provided',
        global: false
      })
      .option('branches', {
        default: 0,
        description: 'what % of branches must be covered?',
        global: false
      })
      .option('functions', {
        default: 0,
        description: 'what % of functions must be covered?',
        global: false
      })
      .option('lines', {
        default: 90,
        description: 'what % of lines must be covered?',
        global: false
      })
      .option('statements', {
        default: 0,
        description: 'what % of statements must be covered?',
        global: false
      })
      .option('source-map', {
        default: true,
        type: 'boolean',
        description: 'should nyc detect and handle source maps?',
        global: false
      })
      .option('per-file', {
        default: false,
        type: 'boolean',
        description: 'check thresholds per file',
        global: false
      })
      .option('produce-source-map', {
        default: false,
        type: 'boolean',
        description: "should nyc's instrumenter produce source maps?",
        global: false
      })
      .option('instrument', {
        default: true,
        type: 'boolean',
        description: 'should nyc handle instrumentation?',
        global: false
      })
      .option('hook-run-in-context', {
        default: true,
        type: 'boolean',
        description: 'should nyc wrap vm.runInThisContext?',
        global: false
      })
      .option('show-process-tree', {
        describe: 'display the tree of spawned processes',
        default: false,
        type: 'boolean',
        global: false
      })
      .option('clean', {
        describe: 'should the .nyc_output folder be cleaned before executing tests',
        default: true,
        type: 'boolean',
        global: false
      })
      .option('temp-directory', {
        describe: 'directory to output raw coverage information to',
        default: './.nyc_output',
        global: false
      })
      .pkgConf('nyc', cwd || process.cwd())
      .example('$0 npm test', 'instrument your tests with coverage')
      .example('$0 --require babel-core/register npm test', 'instrument your tests with coverage and babel')
      .example('$0 report --reporter=text-lcov', 'output lcov report after running your tests')
      .epilog('visit https://git.io/vHysA for list of available reporters')
      .boolean('help')
      .boolean('h')
      .boolean('version')
  }
  
  // decorate yargs with all the actions
  // that would make it exit: help, version, command.
  Config.decorateYargs = function (yargs) {
    return yargs
      .help('h')
      .alias('h', 'help')
      .version()
      .command(require('../lib/commands/instrument'))
  }
  
  module.exports = Config
  