/**
 * @module util
 */

'use strict'

const child = require('child_process')
const fs = require('fs-extra')
const path = require('path')

const debug = require('debug')

/**
 * This callback is used across signing and flattening.
 * @callback RequestCallback
 * @param {?Error} err
 */

/** @function */
const debuglog = module.exports.debuglog = debug('electron-osx-sign')
debuglog.log = console.log.bind(console)

/** @function */
const debugwarn = module.exports.debugwarn = debug('electron-osx-sign:warn')
debugwarn.log = console.warn.bind(console)

/** @function */
const removePassword = function (input) {
  return input.replace(/(-P |pass:|\/p|-pass )([^ ]+)/, function (match, p1, p2) {
    return `${p1}***`
  })
}

/** @function */
module.exports.execFileAsync = function (file, args, options) {
  if (debuglog.enabled) {
    debuglog('Executing...', file, args && Array.isArray(args) ? removePassword(args.join(' ')) : '')
  }

  return new Promise(function (resolve, reject) {
    child.execFile(file, args, options, function (err, stdout, stderr) {
      if (err) {
        debuglog('Error executing file:', '\n',
          '> Stdout:', stdout, '\n',
          '> Stderr:', stderr)
        reject(err)
        return
      }
      resolve(stdout)
    })
  })
}

/**
 * This function returns a flattened list of elements from an array of lists.
 * @function
 * @param {*} list - List.
 * @returns Flattened list.
 */
module.exports.flatList = function (list) {
  function populateResult(list) {
    if (!Array.isArray(list)) {
      result.push(list)
    } else if (list.length > 0) {
      for (let item of list) if (item) populateResult(item)
    }
  }

  let result = []
  populateResult(list)
  return result
}

/**
 * This function returns the path to app contents.
 * @function
 * @param {Object} opts - Options.
 * @returns {string} App contents path.
 */
var getAppContentsPath = module.exports.getAppContentsPath = function (opts) {
  return path.join(opts.app, 'Contents')
}

/**
 * This function returns the path to app frameworks within contents.
 * @function
 * @param {Object} opts - Options.
 * @returns {string} App frameworks path.
 */
var getAppFrameworksPath = module.exports.getAppFrameworksPath = function (opts) {
  return path.join(getAppContentsPath(opts), 'Frameworks')
}

/**
 * This function returns a promise copying a file from the source to the target.
 * @function
 * @param {string} source - Source path.
 * @param {string} target - Target path.
 * @returns {Promise} Promise.
 */
module.exports.copyFileAsync = function (source, target) {
  debuglog('Copying file...', '\n',
    '> Source:', source, '\n',
    '> Target:', target)
  return new Promise(function (resolve, reject) {
    var readStream = fs.createReadStream(source)
    readStream.on('error', reject)
    var writeStream = fs.createWriteStream(target)
    writeStream.on('error', reject)
    writeStream.on('close', resolve)
    readStream.pipe(writeStream)
  })
}

/**
 * This function returns a promise with platform resolved.
 * @function
 * @param {Object} opts - Options.
 * @returns {Promise} Promise resolving platform.
 */
var detectElectronPlatformAsync = module.exports.detectElectronPlatformAsync = function (opts) {
  return new Promise(function (resolve) {
    var appFrameworksPath = getAppFrameworksPath(opts)
    // The presence of Squirrel.framework identifies a Mac App Store build as used in https://github.com/atom/electron/blob/master/docs/tutorial/mac-app-store-submission-guide.md
    return fs.lstat(path.join(appFrameworksPath, 'Squirrel.framework'))
      .then(function () {
        resolve('darwin')
      })
      .catch(function () {
        resolve('mas')
      })
  })
}

const isBinaryFile = require("istextorbinary").isBinary;

/**
 * This function returns a promise resolving the file path if file binary. We check filepath extension first to reduce overhead of reading the file to a buffer for it to scan start/mid/end encoding of the file
 * @function
 * @param {string} filePath - Path to file.
 * @returns {Promise} Promise resolving file path or undefined.
 */
const getFilePathIfBinarySync = module.exports.getFilePathIfBinarySync = function (filePath) {
  const forceAllowedExts = [
    '.dylib', // Dynamic library
    '.node' // Native node addon
  ]
  const name = path.basename(filePath)
  const ext = path.extname(filePath)

  // Sometimes .node is the base name, not as a file extension
  // https://github.com/electron/electron-osx-sign/pull/169
  if (forceAllowedExts.includes(ext) || forceAllowedExts.includes(name)) {
    return filePath
  }
  // Still consider the file as binary if extension is empty or seems invalid
  // https://github.com/electron-userland/electron-builder/issues/5465
  if ((ext === '' || ext.indexOf(' ') >= 0) && name[0] !== '.') {
    return (isBinaryFile(filePath, null) || isBinaryFile(null, fs.readFileSync(filePath))) ? filePath : undefined
  }
  return undefined
}

/**
 * This function returns a promise validating opts.app, the application to be signed or flattened.
 * @function
 * @param {Object} opts - Options.
 * @returns {Promise} Promise.
 */
module.exports.validateOptsAppAsync = async function (opts) {
  if (!opts.app) {
    throw new Error('Path to aplication must be specified.')
  }
  if (path.extname(opts.app) !== '.app') {
    throw new Error('Extension of application must be `.app`.')
  }
  await fs.lstat(opts.app)
}

/**
 * This function returns a promise validating opts.platform, the platform of Electron build. It allows auto-discovery if no opts.platform is specified.
 * @function
 * @param {Object} opts - Options.
 * @returns {Promise} Promise.
 */
module.exports.validateOptsPlatformAsync = function (opts) {
  if (opts.platform) {
    if (opts.platform === 'mas' || opts.platform === 'darwin') {
      return Promise.resolve()
    } else {
      debugwarn('`platform` passed in arguments not supported, checking Electron platform...')
    }
  } else {
    debugwarn('No `platform` passed in arguments, checking Electron platform...')
  }

  return detectElectronPlatformAsync(opts)
    .then(function (platform) {
      opts.platform = platform
    })
}

/**
 * This function returns a promise resolving all child paths within the directory specified.
 * @function
 * @param {string} dirPath - Path to directory.
 * @returns {Promise} Promise resolving child paths needing signing in order.
 */
module.exports.walkAsync = async function (dirPath) {
  debuglog('Walking... ' + dirPath)

  async function _walkAsync(dirPath) {
    const names = await fs.readdir(dirPath)
    return await Promise.all(names.map(async (name) => {
      let filePath = path.join(dirPath, name)
      const stat = await fs.lstat(filePath)
      if (stat.isFile()) {
        const forceRemoveExts = [
          '.cstemp' // Temporary file generated from past codesign
        ]
        if (forceRemoveExts.includes(path.extname(filePath))) {
          debuglog('Removing... ' + filePath)
          await fs.unlink(filePath)
          return
        }
        const binaryPath = getFilePathIfBinarySync(filePath)
        if (binaryPath) {
          return binaryPath
        }
      } else if (stat.isDirectory() && !stat.isSymbolicLink()) {
        const result = await _walkAsync(filePath)
        switch (path.extname(filePath)) {
          case '.app': // Application
          case '.framework': // Framework
            result.push(filePath)
        }
        return result
      }
    }))
  }

  return module.exports.flatList(await _walkAsync(dirPath))
}