index.js

const exec = require('child_process').exec
const fs = require('fs')
const path = require('path')
const stream = require('stream')
const { promisify } = require('util')

const area = require('@mapbox/geojson-area')
const geojsonhint = require('@mapbox/geojsonhint')
const time = require('@tubular/time')
const bbox = require('@turf/bbox').default
const helpers = require('@turf/helpers')
const multiPolygon = helpers.multiPolygon
const polygon = helpers.polygon
const asynclib = require('async')
const got = require('got')
const hasha = require('hasha')
const jsts = require('jsts')
const cloneDeep = require('lodash.clonedeep')
const memoize = require('lodash.memoize')
const hash = require('object-hash')
const rimraf = require('rimraf')
const overpass = require('query-overpass')
const yargs = require('yargs')

const FeatureWriterStream = require('./util/featureWriterStream')
const ProgressStats = require('./util/progressStats')
const { FileCache, FileLookupCache } = require('./util/cache')

let osmBoundarySources = require('./osmBoundarySources.json')
let zoneCfg = require('./timezones.json')
let zoneCfg1970 = {}
let zoneCfgNow = {}
const expectedZoneOverlaps = require('./expectedZoneOverlaps.json')

const argv = yargs
  .option('cache_dir', {
    description: 'Set the cache location, for caching results',
    default: './cache',
    type: 'string'
  })
  .option('dist_dir', {
    description: 'Set the dist location, for the generated release files',
    default: './dist',
    type: 'string'
  })
  .option('downloads_dir', {
    description: 'Set the download location for features from OpenStreetMap',
    default: './downloads',
    type: 'string'
  })
  .option('excluded_zones', {
    description: 'Exclude specified zones',
    type: 'array'
  })
  .option('included_zones', {
    description: 'Include specified zones',
    type: 'array'
  })
  .option('skip_1970_zones', {
    description: 'Skip creation of zones that are the same since 1970',
    type: 'boolean'
  })
  .option('skip_now_zones', {
    description: 'Skip creation of zones that are the same since now',
    type: 'boolean'
  })
  .option('skip_analyze_diffs', {
    description: 'Skip analysis of diffs between versions',
    type: 'boolean'
  })
  .option('skip_analyze_osm_tz_diffs', {
    description: 'Skip analysis of diffs between timezone-boundary-builder output and raw OSM timezone relations',
    type: 'boolean'
  })
  .option('skip_shapefile', {
    description: 'Skip shapefile creation',
    type: 'boolean'
  })
  .option('skip_validation', {
    description: 'Skip validation',
    type: 'boolean'
  })
  .option('skip_zip', {
    description: 'Skip zip creation',
    type: 'boolean'
  })
  .option('working_dir', {
    description: 'Set the working files location for temporary / intermediate files',
    default: './working',
    type: 'string'
  })
  .help()
  .strict()
  .alias('help', 'h')
  .argv

// Resolve the arguments with paths so relative paths become absolute.
const cacheDir = path.resolve(argv.cache_dir)
const downloadsDir = path.resolve(argv.downloads_dir)
const distDir = path.resolve(argv.dist_dir)
const workingDir = path.resolve(argv.working_dir)
const osmDownloadDir = path.join(workingDir, 'osm-downloads')

function hashMd5 (obj) {
  if (!obj) return 'non-object'
  return hash(obj, { algorithm: 'md5' })
}

function loadJsonCacheSync (filename) {
  try {
    return JSON.parse(
      fs.readFileSync(filename, { encoding: 'utf-8' })
    )
  } catch (err) {
    // cache not found, return empty obj
    return {}
  }
}

function writeJsonSync (filename, json) {
  fs.writeFileSync(filename, JSON.stringify(json))
}

function getTimezonePopulation (zone) {
  // return 0 if the timezone is an alias so it doesn't conflict with larger zones
  const zoneData = time.Timezone.from(zone)
  return zoneData.aliasFor ? 0 : zoneData.population
}

let tzdbInitialized = false
function getZoneCfgSinceTime (cutoffTime, cacheFilename) {
  // load cache and return immediately if it exists
  const cachedConfig = loadJsonCacheSync(cacheFilename)
  if (Object.keys(cachedConfig).length > 0) {
    return cachedConfig
  }

  if (!tzdbInitialized) {
    // initialize the tubular time to make sure it has all the latest zones
    time.initTimezoneLarge()
    tzdbInitialized = true
  }

  const newZoneCfg = {}

  // Iterate through all zones to determine which share same timekeeping method since cutoff time
  const timekeepingPatternZones = {}
  Object.keys(zoneCfg).forEach(zone => {
    // calculate which offset pattern this zone follows and add it to list
    const timezoneInstance = time.Timezone.from(zone)
    const currentZoneOffset = timezoneInstance.getOffsetForWallTime(timezoneInstance)
    let timekeepingKey = `${currentZoneOffset}`
    const transitions = timezoneInstance.getAllTransitions()

    if (transitions) {
      // timezone with transitions between daylight savings and standard time since cutoff time
      const futureTransitionsHash = hashMd5(transitions.filter(t => t.transitionTime > cutoffTime))
      timekeepingKey = `${currentZoneOffset}-${futureTransitionsHash}`
    }

    if (!timekeepingPatternZones[timekeepingKey]) {
      timekeepingPatternZones[timekeepingKey] = []
    }
    timekeepingPatternZones[timekeepingKey].push(zone)
  })

  // iterate through each set of zones with the same future timekeeping method to determine
  // which has the largest population
  Object.keys(timekeepingPatternZones).forEach(k => {
    timekeepingPatternZones[k].sort((a, b) => getTimezonePopulation(b) - getTimezonePopulation(a))
    newZoneCfg[timekeepingPatternZones[k][0]] = timekeepingPatternZones[k]
  })

  writeJsonSync(cacheFilename, newZoneCfg)

  return newZoneCfg
}

if (!argv.skip_now_zones) {
  console.log('Generating zone config for zones with the same timekeeping method since now')
  zoneCfgNow = getZoneCfgSinceTime(
    (new Date()).getTime(),
    path.join(cacheDir, 'zone-config-now.json')
  )
}

if (!argv.skip_1970_zones) {
  console.log('Generating zone config for zones with the same timekeeping method since 1970')
  zoneCfg1970 = getZoneCfgSinceTime(
    0,
    path.join(cacheDir, 'zone-config-1970.json')
  )
}

// allow building of only a specified zones
let includedZones = []
let excludedZones = []
if (argv.included_zones || argv.excluded_zones) {
  if (argv.included_zones) {
    const newZoneCfg = {}
    const newZoneCfg1970 = {}
    const newZoneCfgNow = {}
    includedZones = argv.included_zones
    includedZones.forEach((zoneName) => {
      if (
        !zoneCfg[zoneName] ||
        (!argv.skip_1970_zones && !zoneCfg1970[zoneName]) ||
        (!argv.skip_now_zones && !zoneCfgNow[zoneName])
      ) {
        console.error(`${zoneName} is not a valid timezone identifier!`)
        process.exit(1)
      }
      newZoneCfg[zoneName] = zoneCfg[zoneName]
      newZoneCfg1970[zoneName] = zoneCfg1970[zoneName]
      newZoneCfgNow[zoneName] = zoneCfgNow[zoneName]
    })
    zoneCfg = newZoneCfg
    zoneCfg1970 = newZoneCfg1970
    zoneCfgNow = newZoneCfgNow
  }
  if (argv.excluded_zones) {
    const newZoneCfg = {}
    const newZoneCfg1970 = {}
    const newZoneCfgNow = {}
    excludedZones = argv.excluded_zones
    Object.keys(zoneCfg).forEach((zoneName) => {
      if (
        !zoneCfg[zoneName] ||
        (!argv.skip_1970_zones && !zoneCfg1970[zoneName]) ||
        (!argv.skip_now_zones && !zoneCfgNow[zoneName])
      ) {
        console.error(`${zoneName} is not a valid timezone identifier!`)
        process.exit(1)
      }
      if (!excludedZones.includes(zoneName)) {
        newZoneCfg[zoneName] = zoneCfg[zoneName]
        newZoneCfg1970[zoneName] = zoneCfg1970[zoneName]
        newZoneCfgNow[zoneName] = zoneCfgNow[zoneName]
      }
    })
    zoneCfg = newZoneCfg
    zoneCfg1970 = newZoneCfg1970
    zoneCfgNow = newZoneCfgNow
  }

  // filter out unneccessary downloads
  const newOsmBoundarySources = {}
  Object.keys(zoneCfg).forEach((zoneName) => {
    zoneCfg[zoneName].forEach((op) => {
      if (op.source === 'overpass') {
        newOsmBoundarySources[op.id] = osmBoundarySources[op.id]
      }
    })
  })

  osmBoundarySources = newOsmBoundarySources
}

const geoJsonReader = new jsts.io.GeoJSONReader()
const geoJsonWriter = new jsts.io.GeoJSONWriter()
const precisionModel = new jsts.geom.PrecisionModel(1000000)
const precisionReducer = new jsts.precision.GeometryPrecisionReducer(precisionModel)
const finalZones = {}
const final1970Zones = {}
const finalNowZones = {}
let lastReleaseName
let lastReleaseJSONfile
const minRequestGap = 8
let curRequestGap = 8
const bufferDistance = 0.01

function safeMkdir (dirname, callback) {
  fs.mkdir(dirname, function (err) {
    if (err && err.code === 'EEXIST') {
      callback()
    } else {
      callback(err)
    }
  })
}

function debugGeo (
  op,
  a,
  b,
  reducePrecision,
  bufferAfterPrecisionReduction
) {
  let result

  if (reducePrecision) {
    a = precisionReducer.reduce(a)
    b = precisionReducer.reduce(b)
  }

  try {
    switch (op) {
      case 'union':
        result = a.union(b)
        break
      case 'intersection':
        result = a.intersection(b)
        break
      case 'intersects':
        result = a.intersects(b)
        break
      case 'diff':
        result = a.difference(b)
        break
      default:
        throw new Error('invalid op: ' + op)
    }
  } catch (e) {
    if (e.name === 'TopologyException') {
      if (reducePrecision) {
        if (bufferAfterPrecisionReduction) {
          console.log('Encountered TopologyException, retry with buffer increase')
          return debugGeo(
            op,
            a.buffer(bufferDistance),
            b.buffer(bufferDistance),
            true,
            bufferAfterPrecisionReduction
          )
        } else {
          throw new Error('Encountered TopologyException after reducing precision')
        }
      } else {
        console.log('Encountered TopologyException, retry with GeometryPrecisionReducer')
        return debugGeo(op, a, b, true, bufferAfterPrecisionReduction)
      }
    }
    console.log('op err')
    console.log(e)
    console.log(e.stack)
    fs.writeFileSync('debug_' + op + '_a.json', JSON.stringify(geoJsonWriter.write(a)))
    fs.writeFileSync('debug_' + op + '_b.json', JSON.stringify(geoJsonWriter.write(b)))
    throw e
  }

  return result
}

function fetchIfNeeded (file, superCallback, downloadCallback, fetchFn) {
  // check for file that got downloaded
  fs.stat(file, function (err) {
    if (!err) {
      // file found, skip download steps
      return superCallback()
    }
    // check for manual file that got fixed and needs validation
    const fixedFile = file.replace('.json', '_fixed.json')
    fs.stat(fixedFile, function (err) {
      if (!err) {
        // file found, return fixed file
        return downloadCallback(null, require(fixedFile))
      }
      // no manual fixed file found, download from overpass
      fetchFn()
    })
  })
}

function geoJsonToGeom (geoJson) {
  try {
    return geoJsonReader.read(JSON.stringify(geoJson))
  } catch (e) {
    console.error('error converting geojson to geometry')
    fs.writeFileSync('debug_geojson_read_error.json', JSON.stringify(geoJson))
    throw e
  }
}

function geomToGeoJson (geom) {
  return geoJsonWriter.write(geom)
}

function geomToGeoJsonString (geom) {
  return JSON.stringify(geoJsonWriter.write(geom))
}

const downloadProgress = new ProgressStats(
  'Downloading',
  Object.keys(osmBoundarySources).length
)

const downloadOSMZoneProgress = new ProgressStats(
  'Downloading OSM Zone',
  Object.keys(zoneCfg).length
)

/**
 * Download something from overpass and convert it into GeoJSON.
 *
 * @param  {string} queryName  Name of the query (for debugging purposes)
 * @param  {object} overpassConfig Config used to build overpass query
 * @param  {string} filename  Filename to save result to
 * @param  {function} overpassDownloadCallback  The callback to call when done
 */
function downloadFromOverpass (
  queryName,
  overpassConfig,
  filename,
  overpassDownloadCallback
) {
  let query = '[out:json][timeout:60];('
  if (overpassConfig.way) {
    query += 'way'
  } else {
    query += 'relation'
  }

  const queryKeys = Object.keys(overpassConfig)

  for (let i = queryKeys.length - 1; i >= 0; i--) {
    const k = queryKeys[i]
    if (k === 'way') continue
    const v = overpassConfig[k]

    query += '["' + k + '"="' + v + '"]'
  }

  query += ';);out body;>;out meta qt;'

  // query-overpass sometimes makes duplicate callbacks, so keep track of the callbacks and
  // only do a next action once.
  let curOverpassQueryAttempt = 0
  const overpassAttempts = {}

  asynclib.auto({
    fetchFromOverpassIfNeeded: function (cb) {
      console.log('downloading from overpass')
      fetchIfNeeded(filename, overpassDownloadCallback, cb, function () {
        const overpassResponseHandler = function (err, data, overpassAttempt) {
          if (overpassAttempts[overpassAttempt]) {
            // Skip duplicate callback
            return
          }
          overpassAttempts[overpassAttempt] = true
          if (err) {
            console.log(err)
            console.log('Increasing overpass request gap')
            curRequestGap *= 2
            makeQuery()
          } else {
            console.log('Success, decreasing overpass request gap')
            curRequestGap = Math.max(minRequestGap, curRequestGap / 2)
            cb(null, data)
          }
        }
        const makeQuery = function () {
          console.log('waiting ' + curRequestGap + ' seconds')
          setTimeout(function () {
            curOverpassQueryAttempt++
            overpass(
              query,
              (err, data) => overpassResponseHandler(err, data, curOverpassQueryAttempt),
              { flatProperties: true }
            )
          }, curRequestGap * 1000)
        }
        makeQuery()
      })
    },
    validateOverpassResult: ['fetchFromOverpassIfNeeded', function (results, cb) {
      const data = results.fetchFromOverpassIfNeeded
      if (!data.features) {
        const err = new Error(`Invalid geojson from overpass for query: ${queryName}`)
        return cb(err)
      }
      if (data.features.length === 0) {
        console.error('No data for the following query:')
        console.error(query)
        console.error('To read more about this error, please visit https://git.io/vxKQL')
        return cb(new Error('No data found for from overpass query'))
      }
      cb()
    }],
    saveSingleMultiPolygon: ['validateOverpassResult', function (results, cb) {
      const data = results.fetchFromOverpassIfNeeded
      let combined

      // union all multi-polygons / polygons into one
      for (let i = data.features.length - 1; i >= 0; i--) {
        const curOsmGeom = data.features[i].geometry
        const curOsmProps = data.features[i].properties
        if (
          (curOsmGeom.type === 'Polygon' || curOsmGeom.type === 'MultiPolygon') &&
          curOsmProps.type === 'boundary' // need to make sure enclaves aren't unioned
        ) {
          console.log('combining border')
          let errors = geojsonhint.hint(curOsmGeom)
          if (errors && errors.length > 0) {
            const stringifiedGeojson = JSON.stringify(curOsmGeom, null, 2)
            errors = geojsonhint.hint(stringifiedGeojson)
            console.error('Invalid geojson received in Overpass Result')
            console.error('Overpass query: ' + query)
            const problemFilename = `${queryName}_convert_to_geom_error.json`
            fs.writeFileSync(problemFilename, stringifiedGeojson)
            console.error('saved problem file to ' + problemFilename)
            console.error('To read more about this error, please visit https://git.io/vxKQq')
            return cb(errors)
          }
          let curGeom
          try {
            curGeom = geoJsonToGeom(curOsmGeom)
          } catch (e) {
            console.error('error converting overpass result to geojson')
            console.error(e)

            fs.writeFileSync(
              `${queryName}_convert_to_geom_error-all-features.json`,
              JSON.stringify(data)
            )
            return cb(e)
          }
          if (!combined) {
            combined = curGeom
          } else {
            combined = debugGeo('union', curGeom, combined)
          }
        }
      }
      try {
        fs.writeFile(filename, geomToGeoJsonString(combined), cb)
      } catch (e) {
        console.error('error writing combined border to geojson')
        fs.writeFileSync(
          queryName + '_combined_border_convert_to_geom_error.json',
          JSON.stringify(data)
        )
        return cb(e)
      }
    }]
  }, overpassDownloadCallback)
}

function downloadOsmBoundary (boundaryId, boundaryCallback) {
  const boundaryFilename = downloadsDir + '/' + boundaryId + '.json'

  downloadProgress.beginTask(`getting data for ${boundaryId}`, true)

  downloadFromOverpass(
    boundaryId,
    osmBoundarySources[boundaryId],
    boundaryFilename,
    boundaryCallback
  )
}

function downloadOsmTimezoneBoundary (tzId, boundaryCallback) {
  const tzBoundayName = `${tzId.replace(/\//g, '-')}-tz`
  const boundaryFilename = path.join(downloadsDir, `${tzBoundayName}.json`)
  const workingBoundaryFilename = path.join(osmDownloadDir, `${tzBoundayName}.json`)

  downloadOSMZoneProgress.beginTask(`getting data for ${tzBoundayName}`, true)

  // the downloads directory is cleared of all timezone boundaries not downloaded from OSM (there
  // are still a few in here with manual definitions). Therefore, keep a copy of all OSM downloads
  // so they aren't redownloaded during multiple reruns of the script

  function copyToOsmDownloadFolder (err) {
    if (err) return boundaryCallback(err)
    fs.copyFile(boundaryFilename, workingBoundaryFilename, boundaryCallback)
  }

  // Before downloading from Overpass, check if there's a copy in the working folder. Since osm
  // downloads are always after production zones, it is safe to copy an osm boundary because a
  // production one would've already been downloaded in the event it were deleted in order to force
  // the retrieval of a new zone.
  fs.stat(
    boundaryFilename,
    (err, stats) => {
      if (!err) {
        // file found, initiate eventual callback
        return copyToOsmDownloadFolder()
      }
      // check for file in working dir
      fs.stat(
        workingBoundaryFilename,
        (err, stats) => {
          if (!err) {
            // file exists, copy over
            return fs.copyFile(workingBoundaryFilename, boundaryFilename, boundaryCallback)
          }
          // file doesn't exist, download from overpass
          downloadFromOverpass(
            tzBoundayName,
            { timezone: tzId },
            boundaryFilename,
            err => {
              if (err) {
                // assume no data or unparseable data, write a null island
                fs.writeFile(
                  boundaryFilename,
                  JSON.stringify(
                    {
                      type: 'Polygon',
                      coordinates: [
                        [[-0.1, -0.1], [0.1, -0.1], [0.1, 0.1], [-0.1, 0.1], [-0.1, -0.1]]
                      ]
                    }
                  ),
                  copyToOsmDownloadFolder
                )
              } else {
                copyToOsmDownloadFolder()
              }
            }
          )
        }
      )
    }
  )
}

function safeTzFilename (tzid) {
  return tzid.replace(/\//g, '__')
}

function getFinalTzOutputFilename (tzid) {
  return path.join(workingDir, `${safeTzFilename(tzid)}.json`)
}

function getFinal1970TzOutputFilename (tzid) {
  return path.join(workingDir, `${safeTzFilename(tzid)}-1970.json`)
}

function getFinalNowTzOutputFilename (tzid) {
  return path.join(workingDir, `${safeTzFilename(tzid)}-now.json`)
}

function getSourceDownloadName (id) {
  return downloadsDir + '/' + id + '.json'
}

/**
 * Get the geometry of the requested source data
 *
 * @return {Object} geom  The geometry of the source
 * @param {Object} source  An object representing the data source
 *   must have `source` key and then either:
 *     - `id` if from a file
 *     - `id` if from a file
 */
function getDataSource (source) {
  let geoJson
  if (source.source === 'overpass') {
    geoJson = require(getSourceDownloadName(source.id))
  } else if (source.source === 'manual-polygon') {
    geoJson = polygon(source.data).geometry
  } else if (source.source === 'manual-multipolygon') {
    geoJson = multiPolygon(source.data).geometry
  } else if (source.source === 'final') {
    geoJson = require(getFinalTzOutputFilename(source.id))
  } else if (source.source === 'final1970') {
    geoJson = require(getFinal1970TzOutputFilename(source.id))
  } else if (source.source === 'finalNow') {
    geoJson = require(getFinalNowTzOutputFilename(source.id))
  } else {
    const err = new Error('unknown source: ' + source.source)
    throw err
  }
  return geoJsonToGeom(geoJson)
}

/**
 * Post process created timezone boundary.
 * - remove small holes and exclaves
 * - reduce geometry precision
 *
 * @param  {Geometry} geom  The jsts geometry of the timezone
 * @param  {boolean} returnAsObject if true, return as object, otherwise return stringified
 * @return {Object|String}         geojson as object or stringified
 */
function postProcessZone (geom, returnAsObject) {
  // reduce precision of geometry
  const geojson = geomToGeoJson(precisionReducer.reduce(geom))

  // iterate through all polygons
  const filteredPolygons = []
  let allPolygons = geojson.coordinates
  if (geojson.type === 'Polygon') {
    allPolygons = [geojson.coordinates]
  }

  allPolygons.forEach((curPolygon, idx) => {
    // remove any polygon with very small area
    const polygonFeature = polygon(curPolygon)
    const polygonArea = area.geometry(polygonFeature.geometry)

    if (polygonArea < 1) return

    // find all holes
    const filteredLinearRings = []

    curPolygon.forEach((curLinearRing, lrIdx) => {
      if (lrIdx === 0) {
        // always keep first linearRing
        filteredLinearRings.push(curLinearRing)
      } else {
        const polygonFromLinearRing = polygon([curLinearRing])
        const linearRingArea = area.geometry(polygonFromLinearRing.geometry)

        // only include holes with relevant area
        if (linearRingArea > 1) {
          filteredLinearRings.push(curLinearRing)
        }
      }
    })

    filteredPolygons.push(filteredLinearRings)
  })

  // recompile to geojson string
  const newGeojson = {
    type: geojson.type
  }

  if (geojson.type === 'Polygon') {
    newGeojson.coordinates = filteredPolygons[0]
  } else {
    newGeojson.coordinates = filteredPolygons
  }

  return returnAsObject ? newGeojson : JSON.stringify(newGeojson)
}

const buildingProgress = new ProgressStats(
  'Building',
  Object.keys(zoneCfg).length
)

function makeTimezoneBoundaries (callback) {
  // load cache if available
  const tzBoundaryCache = new FileLookupCache({
    filename: path.join(cacheDir, 'boundary-creation-cache.json')
  })

  tzBoundaryCache.init(() => {
    asynclib.each(
      Object.keys(zoneCfg),
      (tzid, cb) => {
        buildingProgress.beginTask(`makeTimezoneBoundary for ${tzid}`, true)

        const tzFilename = getFinalTzOutputFilename(tzid)
        const ops = zoneCfg[tzid]
        let geom

        asynclib.map(
          ops,
          (op, opCb) => {
            const newOp = cloneDeep(op)
            if (op.source === 'overpass') {
              hasha.fromFile(getSourceDownloadName(op.id))
                .then(val => {
                  newOp.source = val
                  opCb(null, newOp)
                })
                .catch(opCb)
            } else {
              opCb(null, newOp)
            }
          },
          (err, hashableOps) => {
            if (err) return cb(err)
            tzBoundaryCache.calculate({
              cacheKey: hashMd5(hashableOps),
              outputFilename: tzFilename,
              calculateFn: calculateCb => {
                console.log(`makeTimezoneBoundary for ${tzid}`)
                asynclib.eachSeries(
                  ops,
                  (task, taskCb) => {
                    const taskData = getDataSource(task)
                    console.log('-', task.op, task.id)
                    if (task.op === 'init') {
                      geom = taskData
                    } else if (task.op === 'intersect') {
                      geom = debugGeo('intersection', geom, taskData)
                    } else if (task.op === 'difference') {
                      geom = debugGeo('diff', geom, taskData)
                    } else if (task.op === 'difference-reverse-order') {
                      geom = debugGeo('diff', taskData, geom)
                    } else if (task.op === 'union') {
                      geom = debugGeo('union', geom, taskData)
                    } else {
                      const err = new Error('unknown op: ' + task.op)
                      return taskCb(err)
                    }
                    taskCb()
                  },
                  opsErr => {
                    if (opsErr) return calculateCb(err)
                    calculateCb(null, postProcessZone(geom))
                  }
                )
              },
              callback: cb
            })
          }
        )
      },
      err => {
        if (err) return callback(err)
        tzBoundaryCache.end(callback)
      }
    )
  })
}

function makeDerivedTimezoneBoundaries (strategy, callback) {
  const cfg = (
    strategy === '1970'
      ? {
          cacheFilename: path.join(cacheDir, 'derived-1970-cache.json'),
          derivedZoneConfig: zoneCfg1970,
          getFinalTzFilenameFn: getFinal1970TzOutputFilename,
          loadZonesInMemoryFn: loadFinal1970ZonesIntoMemory,
          progressStatsName: 'Building 1970 zones',
          progressStatsUpdatePrefix: 'make1970TimezoneBoundary for'
        }
      : {
          cacheFilename: path.join(cacheDir, 'derived-now-cache.json'),
          derivedZoneConfig: zoneCfgNow,
          getFinalTzFilenameFn: getFinalNowTzOutputFilename,
          loadZonesInMemoryFn: loadFinalNowZonesIntoMemory,
          progressStatsName: 'Building Now zones',
          progressStatsUpdatePrefix: 'makeNowTimezoneBoundary for'
        }
  )

  const buildingProgress = new ProgressStats(
    cfg.progressStatsName,
    Object.keys(cfg.derivedZoneConfig).length
  )

  // load cache if available
  const tzBoundaryCache = new FileLookupCache({
    filename: cfg.cacheFilename
  })

  tzBoundaryCache.init(() => {
    asynclib.each(
      Object.keys(cfg.derivedZoneConfig),
      (tzid, cb) => {
        const message = `${cfg.progressStatsUpdatePrefix} ${tzid}`
        buildingProgress.beginTask(message, true)

        tzBoundaryCache.calculate({
          cacheKey: hashMd5(cfg.derivedZoneConfig[tzid].map(getZoneGeomHash)),
          outputFilename: cfg.getFinalTzFilenameFn(tzid),
          calculateFn: calculateCb => {
            console.log(message)
            let geom = getDataSource({ source: 'final', id: tzid })

            cfg.derivedZoneConfig[tzid].forEach(zone => {
              console.log('-', zone)
              if (zone === tzid) return
              const zoneData = getDataSource({ source: 'final', id: zone })
              geom = debugGeo('union', geom, zoneData)
            })

            calculateCb(null, postProcessZone(geom))
          },
          callback: cb
        })
      },
      err => {
        if (err) return callback(err)
        cfg.loadZonesInMemoryFn()
        tzBoundaryCache.end(callback)
      }
    )
  })
}

function loadFinalZonesIntoMemory () {
  console.log('load zones into memory')
  Object.keys(zoneCfg).forEach(tzid => {
    finalZones[tzid] = getDataSource({ source: 'final', id: tzid })
  })
}

function loadFinal1970ZonesIntoMemory () {
  console.log('load 1970 zones into memory')
  Object.keys(zoneCfg1970).forEach(tzid => {
    final1970Zones[tzid] = getDataSource({ source: 'final1970', id: tzid })
  })
}

function loadFinalNowZonesIntoMemory () {
  console.log('load Now zones into memory')
  Object.keys(zoneCfgNow).forEach(tzid => {
    finalNowZones[tzid] = getDataSource({ source: 'finalNow', id: tzid })
  })
}

function roundDownToTenth (n) {
  return Math.floor(n * 10) / 10
}

function roundUpToTenth (n) {
  return Math.ceil(n * 10) / 10
}

function formatBounds (bounds) {
  let boundsStr = '['
  boundsStr += roundDownToTenth(bounds[0]) + ', '
  boundsStr += roundDownToTenth(bounds[1]) + ', '
  boundsStr += roundUpToTenth(bounds[2]) + ', '
  boundsStr += roundUpToTenth(bounds[3]) + ']'
  return boundsStr
}

const getZoneGeomHash = memoize((tzid) => {
  const zoneFilename = getFinalTzOutputFilename(tzid)
  try {
    fs.statSync(zoneFilename)
  } catch (err) {
    return `${tzid}-filenotfound`
  }
  return `${tzid}-${hasha.fromFileSync(zoneFilename, { algorithm: 'md5' })}`
})

function validateTimezoneBoundaries (callback) {
  console.log('do validation... this may take a few minutes with fresh data')

  // load cache if available
  const validationCache = new FileCache({
    filename: path.join(cacheDir, 'validation-cache.json')
  })

  validationCache.init(() => {
    let allZonesOk = true
    const zones = Object.keys(zoneCfg)

    const numZones = Object.keys(zoneCfg).length
    const validationProgress = new ProgressStats(
      'Validation',
      numZones * (numZones + 1) / 2
    )
    let lastPct = 0

    const validationCalcs = []

    for (let i = 0; i < zones.length; i++) {
      for (let j = i + 1; j < zones.length; j++) {
        validationCalcs.push({ tzid: zones[i], compareTzid: zones[j] })
      }
    }

    asynclib.each(
      validationCalcs,
      ({ tzid, compareTzid }, validationCb) => {
        const allowedOverlapBounds = expectedZoneOverlaps[`${tzid}-${compareTzid}`] || expectedZoneOverlaps[`${compareTzid}-${tzid}`]
        validationCache.calculate({
          cacheKey: `${getZoneGeomHash(tzid)}-${getZoneGeomHash(compareTzid)}-${hashMd5(allowedOverlapBounds)}`,
          calculateFn: calculateCb => {
            const zoneGeom = finalZones[tzid]
            const compareZoneGeom = finalZones[compareTzid]

            let intersects = false
            try {
              intersects = debugGeo('intersects', zoneGeom, compareZoneGeom)
            } catch (e) {
              console.warn('warning, encountered intersection error with zone ' + tzid + ' and ' + compareTzid)
            }
            if (intersects) {
              const intersectedGeom = debugGeo('intersection', zoneGeom, compareZoneGeom)
              const intersectedArea = intersectedGeom.getArea()

              if (intersectedArea > 0.0001) {
                // check if the intersected area(s) are one of the expected areas of overlap
                const overlapsGeoJson = geoJsonWriter.write(intersectedGeom)

                // these zones are allowed to overlap in certain places, make sure the
                // found overlap(s) all fit within the expected areas of overlap
                if (allowedOverlapBounds) {
                  // if the overlaps are a multipolygon, make sure each individual
                  // polygon of overlap fits within at least one of the expected
                  // overlaps
                  let overlapsPolygons
                  switch (overlapsGeoJson.type) {
                    case 'MultiPolygon':
                      overlapsPolygons = overlapsGeoJson.coordinates.map(
                        polygonCoords => ({
                          coordinates: polygonCoords,
                          type: 'Polygon'
                        })
                      )
                      break
                    case 'Polygon':
                      overlapsPolygons = [overlapsGeoJson]
                      break
                    case 'GeometryCollection':
                      overlapsPolygons = []
                      overlapsGeoJson.geometries.forEach(geom => {
                        if (geom.type === 'Polygon') {
                          overlapsPolygons.push(geom)
                        } else if (geom.type === 'MultiPolygon') {
                          geom.coordinates.forEach(polygonCoords => {
                            overlapsPolygons.push({
                              coordinates: polygonCoords,
                              type: 'Polygon'
                            })
                          })
                        }
                      })
                      break
                    default:
                      console.error('unexpected geojson overlap type')
                      console.log(overlapsGeoJson)
                      break
                  }

                  let allOverlapsOk = true
                  overlapsPolygons.forEach((polygon, idx) => {
                    const bounds = bbox(polygon)
                    const polygonArea = area.geometry(polygon)
                    if (
                      polygonArea > 10 && // ignore small polygons
                      !allowedOverlapBounds.some(allowedBounds =>
                        allowedBounds.bounds[0] <= bounds[0] && // minX
                          allowedBounds.bounds[1] <= bounds[1] && // minY
                          allowedBounds.bounds[2] >= bounds[2] && // maxX
                          allowedBounds.bounds[3] >= bounds[3] // maxY
                      )
                    ) {
                      console.error(`Unexpected intersection (${polygonArea} area) with bounds: ${formatBounds(bounds)}`)
                      allOverlapsOk = false
                    }
                  })

                  if (allOverlapsOk) {
                    return calculateCb(null, { ok: true })
                  }
                }

                // at least one unexpected overlap found, output an error and write debug file
                console.error('Validation error: ' + tzid + ' intersects ' + compareTzid + ' area: ' + intersectedArea)
                const debugFilename = tzid.replace(/\//g, '-') + '-' + compareTzid.replace(/\//g, '-') + '-overlap.json'
                fs.writeFileSync(
                  debugFilename,
                  JSON.stringify(overlapsGeoJson)
                )
                console.error('wrote overlap area as file ' + debugFilename)
                console.error('To read more about this error, please visit https://git.io/vx6nx')
                return calculateCb(null, {
                  intersectedArea,
                  ok: false
                })
              }
            }
            calculateCb(null, { ok: true })
          },
          callback: (err, data) => {
            const curPct = Math.floor(validationProgress.getPercentage())
            if (curPct % 10 === 0 && curPct !== lastPct) {
              validationProgress.printStats('Validating zones', true)
              lastPct = curPct
            }
            validationProgress.logNext()
            if (err) return validationCb(err)
            if (!data.ok) {
              console.error('Validation error: ' + tzid + ' intersects ' + compareTzid)
              allZonesOk = false
            }
            validationCb()
          }
        })
      },
      err => {
        const error = allZonesOk ? null : new Error('Zone validation unsuccessful')
        console.log(allZonesOk ? 'Zones Validated Successfully' : 'Errors found during zone validation')
        if (err) {
          console.error(err)
        }
        validationCache.end((err) => callback(err || error))
      }
    )
  })
}

let oceanZoneBoundaries
let oceanZones = [
  { tzid: 'Etc/GMT-12', left: 172.5, right: 180 },
  { tzid: 'Etc/GMT-11', left: 157.5, right: 172.5 },
  { tzid: 'Etc/GMT-10', left: 142.5, right: 157.5 },
  { tzid: 'Etc/GMT-9', left: 127.5, right: 142.5 },
  { tzid: 'Etc/GMT-8', left: 112.5, right: 127.5 },
  { tzid: 'Etc/GMT-7', left: 97.5, right: 112.5 },
  { tzid: 'Etc/GMT-6', left: 82.5, right: 97.5 },
  { tzid: 'Etc/GMT-5', left: 67.5, right: 82.5 },
  { tzid: 'Etc/GMT-4', left: 52.5, right: 67.5 },
  { tzid: 'Etc/GMT-3', left: 37.5, right: 52.5 },
  { tzid: 'Etc/GMT-2', left: 22.5, right: 37.5 },
  { tzid: 'Etc/GMT-1', left: 7.5, right: 22.5 },
  { tzid: 'Etc/GMT', left: -7.5, right: 7.5 },
  { tzid: 'Etc/GMT+1', left: -22.5, right: -7.5 },
  { tzid: 'Etc/GMT+2', left: -37.5, right: -22.5 },
  { tzid: 'Etc/GMT+3', left: -52.5, right: -37.5 },
  { tzid: 'Etc/GMT+4', left: -67.5, right: -52.5 },
  { tzid: 'Etc/GMT+5', left: -82.5, right: -67.5 },
  { tzid: 'Etc/GMT+6', left: -97.5, right: -82.5 },
  { tzid: 'Etc/GMT+7', left: -112.5, right: -97.5 },
  { tzid: 'Etc/GMT+8', left: -127.5, right: -112.5 },
  { tzid: 'Etc/GMT+9', left: -142.5, right: -127.5 },
  { tzid: 'Etc/GMT+10', left: -157.5, right: -142.5 },
  { tzid: 'Etc/GMT+11', left: -172.5, right: -157.5 },
  { tzid: 'Etc/GMT+12', left: -180, right: -172.5 }
]

if (includedZones.length > 0) {
  oceanZones = oceanZones.filter(oceanZone => includedZones.indexOf(oceanZone) > -1)
}
if (excludedZones.length > 0) {
  oceanZones = oceanZones.filter(oceanZone => excludedZones.indexOf(oceanZone) === -1)
}

function addOceans (callback) {
  console.log('adding ocean boundaries')
  const zones = Object.keys(zoneCfg)

  const oceanProgress = new ProgressStats(
    'Oceans',
    oceanZones.length
  )

  const oceanBoundaryCache = new FileCache({
    filename: path.join(cacheDir, 'ocean-creation-cache.json')
  })

  oceanBoundaryCache.init(() => {
    asynclib.map(
      oceanZones,
      (oceanZone, zoneCb) => {
        oceanProgress.beginTask(oceanZone.tzid, true)
        const geoJson = polygon([[
          [oceanZone.left, 90],
          [oceanZone.left, -90],
          [oceanZone.right, -90],
          [oceanZone.right, 90],
          [oceanZone.left, 90]
        ]]).geometry

        let oceanGeom = geoJsonToGeom(geoJson)

        // filter zones to those that have bounds that apply
        const tzsInBounds = zones.filter(tzid => {
          const zoneEnvelope = finalZones[tzid].getEnvelopeInternal()
          return !(
            zoneEnvelope.getMaxX() < oceanZone.left ||
            zoneEnvelope.getMinX() > oceanZone.right
          )
        })

        oceanBoundaryCache.calculate({
          cacheKey: `${oceanZone.tzid}-${hashMd5(tzsInBounds.map(getZoneGeomHash))}`,
          calculateFn: calculateCb => {
            // diff against applicable zones
            tzsInBounds.forEach(finalZone => {
              oceanGeom = debugGeo('diff', oceanGeom, finalZones[finalZone])
            })

            calculateCb(null, {
              geom: postProcessZone(oceanGeom, true),
              tzid: oceanZone.tzid
            })
          },
          callback: zoneCb
        })
      },
      (err, results) => {
        oceanZoneBoundaries = results
        oceanBoundaryCache.end(error => callback(err || error))
      }
    )
  })
}

function combineAndWriteZones (callback) {
  const regularWriter = new FeatureWriterStream(workingDir + '/combined.json')
  const oceanWriter = new FeatureWriterStream(workingDir + '/combined-with-oceans.json')
  let regular1970Writer
  let ocean1970Writer
  let regularNowWriter
  let oceanNowWriter

  if (!argv.skip_1970_zones) {
    regular1970Writer = new FeatureWriterStream(workingDir + '/combined-1970.json')
    ocean1970Writer = new FeatureWriterStream(workingDir + '/combined-with-oceans-1970.json')
  }

  if (!argv.skip_now_zones) {
    regularNowWriter = new FeatureWriterStream(workingDir + '/combined-now.json')
    oceanNowWriter = new FeatureWriterStream(workingDir + '/combined-with-oceans-now.json')
  }

  Object.keys(zoneCfg).forEach(zoneName => {
    const feature = {
      type: 'Feature',
      properties: { tzid: zoneName },
      geometry: geomToGeoJson(finalZones[zoneName])
    }
    const stringified = JSON.stringify(feature)
    regularWriter.add(stringified)
    oceanWriter.add(stringified)
  })
  if (!argv.skip_1970_zones) {
    Object.keys(zoneCfg1970).forEach(zoneName => {
      const feature = {
        type: 'Feature',
        properties: { tzid: zoneName },
        geometry: geomToGeoJson(final1970Zones[zoneName])
      }
      const stringified = JSON.stringify(feature)
      regular1970Writer.add(stringified)
      ocean1970Writer.add(stringified)
    })
  }
  if (!argv.skip_now_zones) {
    Object.keys(zoneCfgNow).forEach(zoneName => {
      const feature = {
        type: 'Feature',
        properties: { tzid: zoneName },
        geometry: geomToGeoJson(finalNowZones[zoneName])
      }
      const stringified = JSON.stringify(feature)
      regularNowWriter.add(stringified)
      oceanNowWriter.add(stringified)
    })
  }
  oceanZoneBoundaries.forEach(boundary => {
    const feature = {
      type: 'Feature',
      properties: { tzid: boundary.tzid },
      geometry: boundary.geom
    }
    const stringified = JSON.stringify(feature)
    oceanWriter.add(stringified)
    if (!argv.skip_1970_zones) {
      ocean1970Writer.add(stringified)
    }
    if (!argv.skip_now_zones) {
      oceanNowWriter.add(stringified)
    }
  })
  const writerEnders = [
    cb => regularWriter.end(cb),
    cb => oceanWriter.end(cb)
  ]
  if (!argv.skip_1970_zones) {
    writerEnders.push(cb => regular1970Writer.end(cb))
    writerEnders.push(cb => ocean1970Writer.end(cb))
  }
  if (!argv.skip_now_zones) {
    writerEnders.push(cb => regularNowWriter.end(cb))
    writerEnders.push(cb => oceanNowWriter.end(cb))
  }
  asynclib.parallel(writerEnders, callback)
}

function combineAndWriteOSMZones (callback) {
  const osmZoneWriter = new FeatureWriterStream(workingDir + '/combined-osm-zones.json')
  Object.keys(zoneCfg).forEach(tzId => {
    const tzBoundayName = `${tzId.replaceAll('/', '-')}-tz`
    const boundaryFilename = downloadsDir + '/' + tzBoundayName + '.json'
    const feature = {
      type: 'Feature',
      properties: { tzid: tzId },
      geometry: require(boundaryFilename)
    }
    const stringified = JSON.stringify(feature)
    osmZoneWriter.add(stringified)
  })
  osmZoneWriter.end(callback)
}

function downloadLastRelease (cb) {
  // download latest release info
  got(
    'https://api.github.com/repos/evansiroky/timezone-boundary-builder/releases/latest'
  ).json()
    .then(data => {
      // determine last release version name and download link
      lastReleaseName = data.name
      lastReleaseJSONfile = `${workingDir}/${lastReleaseName}.json`
      let lastReleaseDownloadUrl
      for (let i = 0; i < data.assets.length; i++) {
        if (data.assets[i].browser_download_url.indexOf('timezones.geojson') > -1) {
          lastReleaseDownloadUrl = data.assets[i].browser_download_url
        }
      }
      if (!lastReleaseDownloadUrl) {
        return cb(new Error('geojson not found'))
      }

      // check for file that got downloaded
      fs.stat(lastReleaseJSONfile, function (err) {
        if (!err) {
          // file found, skip download steps
          return cb()
        }
        // file not found, download
        console.log(`Downloading latest release to ${lastReleaseJSONfile}.zip`)
        const pipeline = promisify(stream.pipeline)
        pipeline(
          got.stream(lastReleaseDownloadUrl),
          fs.createWriteStream(`${lastReleaseJSONfile}.zip`)
        ).then(() => {
          // unzip file
          console.log(`unzipping latest release from ${lastReleaseJSONfile}.zip`)
          exec(
            `unzip -o ${lastReleaseJSONfile} -d ${workingDir}`,
            err => {
              if (err) { return cb(err) }

              const srcFile = path.join(workingDir, 'combined.json')
              console.log(`unzipped file: ${srcFile}`)

              const destFile = lastReleaseJSONfile
              console.log(`Renaming ${srcFile} to ${destFile}`)
              fs.rename(srcFile, destFile, cb)
            }
          )
        })
      })
    })
}

function zipGeoJsonFiles (cb) {
  const zipCommands = [
    ['timezones.geojson.zip', 'combined.json'],
    ['timezones-with-oceans.geojson.zip', 'combined-with-oceans.json']
  ]
  if (!argv.skip_1970_zones) {
    zipCommands.push(['timezones-1970.geojson.zip', 'combined-1970.json'])
    zipCommands.push(['timezones-with-oceans-1970.geojson.zip', 'combined-with-oceans-1970.json'])
  }
  if (!argv.skip_now_zones) {
    zipCommands.push(['timezones-now.geojson.zip', 'combined-now.json'])
    zipCommands.push(['timezones-with-oceans-now.geojson.zip', 'combined-with-oceans-now.json'])
  }
  asynclib.each(
    zipCommands.map(([dist, working]) => `zip -j ${path.join(distDir, dist)} ${path.join(workingDir, working)}`),
    exec,
    cb
  )
}

function makeShapefile (config, cb) {
  rimraf(config.shapeFileGlob, rimrafErr => {
    if (rimrafErr) { return cb(rimrafErr) }
    exec(
      `ogr2ogr -f "ESRI Shapefile" ${config.shapeFile} ${config.jsonFile}`,
      ogrErr => {
        if (ogrErr) { return cb(ogrErr) }
        if (!config.shapeFileZip) { return cb() }
        exec(`zip -j ${config.shapeFileZip} ${config.shapeFileGlob}`, cb)
      }
    )
  })
}

function makeShapefiles (cb) {
  const shapefileConfigs = [
    { // combined without oceans
      jsonFile: path.join(workingDir, 'combined.json'),
      shapeFile: path.join(workingDir, 'combined-shapefile.shp'),
      shapeFileGlob: path.join(workingDir, 'combined-shapefile.*'),
      shapeFileZip: path.join(distDir, 'timezones.shapefile.zip')
    }, { // combined with oceans
      jsonFile: path.join(workingDir, 'combined-with-oceans.json'),
      shapeFile: path.join(workingDir, 'combined-shapefile-with-oceans.shp'),
      shapeFileGlob: path.join(workingDir, 'combined-shapefile-with-oceans.*'),
      shapeFileZip: path.join(distDir, 'timezones-with-oceans.shapefile.zip')
    }
  ]

  if (!argv.skip_1970_zones) {
    shapefileConfigs.push({ // 1970 without oceans
      jsonFile: path.join(workingDir, 'combined-1970.json'),
      shapeFile: path.join(workingDir, 'combined-shapefile-1970.shp'),
      shapeFileGlob: path.join(workingDir, 'combined-shapefile-1970.*'),
      shapeFileZip: path.join(distDir, 'timezones-1970.shapefile.zip')
    })
    shapefileConfigs.push({ // 1970 with oceans
      jsonFile: path.join(workingDir, 'combined-with-oceans-1970.json'),
      shapeFile: path.join(workingDir, 'combined-shapefile-with-oceans-1970.shp'),
      shapeFileGlob: path.join(workingDir, 'combined-shapefile-with-oceans-1970.*'),
      shapeFileZip: path.join(distDir, 'timezones-with-oceans-1970.shapefile.zip')
    })
  }

  if (!argv.skip_now_zones) {
    shapefileConfigs.push({ // now without oceans
      jsonFile: path.join(workingDir, 'combined-now.json'),
      shapeFile: path.join(workingDir, 'combined-shapefile-now.shp'),
      shapeFileGlob: path.join(workingDir, 'combined-shapefile-now.*'),
      shapeFileZip: path.join(distDir, 'timezones-now.shapefile.zip')
    })
    shapefileConfigs.push({ // now with oceans
      jsonFile: path.join(workingDir, 'combined-with-oceans-now.json'),
      shapeFile: path.join(workingDir, 'combined-shapefile-with-oceans-now.shp'),
      shapeFileGlob: path.join(workingDir, 'combined-shapefile-with-oceans-now.*'),
      shapeFileZip: path.join(distDir, 'timezones-with-oceans-now.shapefile.zip')
    })
  }

  asynclib.each(shapefileConfigs, makeShapefile, cb)
}

function analyzeChangesFromLastRelease (cb) {
  // load last release data into memory
  console.log('loading previous release into memory')
  const lastReleaseData = require(lastReleaseJSONfile)

  // load each feature's geojson into JSTS format and then organized by tzid
  const lastReleaseZones = {}
  lastReleaseData.features.forEach(
    feature => {
      lastReleaseZones[feature.properties.tzid] = feature
    }
  )

  // generate set of keys from last release and current
  const zoneNames = new Set()
  Object.keys(finalZones).forEach(zoneName => zoneNames.add(zoneName))
  Object.keys(lastReleaseZones).forEach(zoneName => zoneNames.add(zoneName))

  // create diff for each zone
  const analysisProgress = new ProgressStats(
    'Analyzing diffs',
    zoneNames.size
  )
  const additionsWriter = new FeatureWriterStream(workingDir + '/additions.json')
  const removalsWriter = new FeatureWriterStream(workingDir + '/removals.json')

  const analysisCache = new FileLookupCache({
    filename: path.join(cacheDir, 'last-release-diffs-analysis-cache.json')
  })

  analysisCache.init(() => {
    asynclib.each(
      zoneNames,
      (zoneName, zoneCb) => {
        analysisCache.calculate({
          cacheKey: `${lastReleaseName}-${zoneName}-${getZoneGeomHash(zoneName)}`,
          outputFilename: path.join(cacheDir, 'last-release-diffs', safeTzFilename(zoneName)),
          calculateFn: calculateCb => {
            console.log(`Analyzing diffs from last release for ${zoneName}`)
            const lastReleaseZone = lastReleaseZones[zoneName]
            const finalZone = finalZones[zoneName]
            const results = {}
            if (finalZone && lastReleaseZone) {
              // some zones take forever to diff unless they are buffered, so buffer by
              // just a small amount
              const lastReleaseGeom = geoJsonToGeom(
                lastReleaseZone.geometry
              ).buffer(bufferDistance)
              const curDataGeom = finalZone.buffer(bufferDistance)

              // don't diff equal geometries
              if (!curDataGeom.equals(lastReleaseGeom)) {
                // diff current - last = additions
                const addition = debugGeo(
                  'diff',
                  curDataGeom,
                  lastReleaseGeom,
                  false,
                  true
                )
                if (addition.getArea() > 0.0001) {
                  results.addition = geomToGeoJson(addition)
                }

                // diff last - current = removals
                const removal = debugGeo(
                  'diff',
                  lastReleaseGeom,
                  curDataGeom,
                  false,
                  true
                )
                if (removal.getArea() > 0.0001) {
                  results.removal = geomToGeoJson(removal)
                }
              }
            } else if (finalZone) {
              results.addition = geomToGeoJson(finalZone)
            } else {
              results.removal = lastReleaseZone
            }
            calculateCb(null, JSON.stringify(results))
          },
          callback: (err, results) => {
            analysisProgress.beginTask(zoneName, true)
            if (err) return zoneCb(err)
            if (results.addition) {
              additionsWriter.add(JSON.stringify({
                type: 'Feature',
                properties: { tzid: zoneName },
                geometry: results.addition
              }))
            }
            if (results.removal) {
              removalsWriter.add(JSON.stringify({
                type: 'Feature',
                properties: { tzid: zoneName },
                geometry: results.removal
              }))
            }
            zoneCb()
          },
          returnFile: true
        })
      },
      err => {
        if (err) return cb(err)
        // write files and close cache
        asynclib.parallel([
          wcb => additionsWriter.end(wcb),
          wcb => removalsWriter.end(wcb),
          ccb => analysisCache.end(ccb)
        ], cb)
      }
    )
  })
}

function assembleAndZipInputData (callback) {
  // since lots of files are at absolute paths, assemble a temporary folder with needed files
  const tempInputFilesDir = path.join(workingDir, 'input-data')
  asynclib.series(
    [
      // remove previous folder
      cb => fs.rm(tempInputFilesDir, { recursive: true }, cb),
      // create it again
      cb => fs.mkdir(tempInputFilesDir, cb),
      // copy necessary files
      copyCb => {
        asynclib.parallel(
          [
            // downloads
            cb => fs.cp(
              downloadsDir,
              path.join(tempInputFilesDir, 'downloads'),
              { recursive: true },
              cb
            ),
            // cache
            cb => fs.cp(
              cacheDir,
              path.join(tempInputFilesDir, 'cache'),
              { recursive: true },
              cb
            ),
            // etc single files (assumes cwd is repo root)
            cb => fs.cp('timezones.json', path.join(tempInputFilesDir, 'timezones.json'), cb),
            cb => fs.cp('osmBoundarySources.json', path.join(tempInputFilesDir, 'osmBoundarySources.json'), cb),
            cb => fs.cp('expectedZoneOverlaps.json', path.join(tempInputFilesDir, 'expectedZoneOverlaps.json'), cb)
          ],
          copyCb
        )
      },
      // zip up
      cb => {
        const zipFilepath = path.join(distDir, 'input-data.zip')
        exec(
          `zip -r ${zipFilepath} input-data`,
          { cwd: workingDir },
          cb
        )
      }
    ],
    callback
  )
}

const autoScript = {
  makeCacheDirAndFns: function (cb) {
    overallProgress.beginTask(`Creating downloads dir (${downloadsDir})`)
    asynclib.series([
      mcb => safeMkdir(cacheDir, mcb),
      mcb => safeMkdir(path.join(cacheDir, 'last-release-diffs'), mcb)
    ], cb)
  },
  makeDownloadsDir: function (cb) {
    overallProgress.beginTask(`Creating downloads dir (${downloadsDir})`)
    safeMkdir(downloadsDir, cb)
  },
  makeWorkingDir: function (cb) {
    overallProgress.beginTask(`Creating working dir (${workingDir})`)
    asynclib.series([
      mcb => safeMkdir(workingDir, mcb),
      mcb => safeMkdir(osmDownloadDir, mcb)
    ], cb)
  },
  makeDistDir: function (cb) {
    overallProgress.beginTask(`Creating dist dir (${distDir})`)
    safeMkdir(distDir, cb)
  },
  getOsmBoundaries: ['makeDownloadsDir', function (results, cb) {
    overallProgress.beginTask('Downloading OSM boundaries')
    asynclib.eachSeries(Object.keys(osmBoundarySources), downloadOsmBoundary, cb)
  }],
  getOsmTzBoundaries: ['getOsmBoundaries', (results, cb) => {
    if (argv.skip_analyze_osm_tz_diffs) {
      overallProgress.beginTask('WARNING: Skipping download of all OSM timezone relations for analysis!')
      cb()
    } else {
      overallProgress.beginTask('Downloading OSM TZ boundaries')
      asynclib.eachSeries(Object.keys(zoneCfg), downloadOsmTimezoneBoundary, cb)
    }
  }],
  downloadLastRelease: ['makeWorkingDir', function (results, cb) {
    if (argv.skip_analyze_diffs) {
      overallProgress.beginTask('WARNING: Skipping download of last release for analysis!')
      cb()
    } else {
      overallProgress.beginTask('Downloading last release for analysis')
      downloadLastRelease(cb)
    }
  }],
  createZones: ['makeCacheDirAndFns', 'makeWorkingDir', 'getOsmBoundaries', function (results, cb) {
    overallProgress.beginTask('Creating timezone boundaries')
    makeTimezoneBoundaries(cb)
  }],
  validateZones: ['createZones', function (results, cb) {
    overallProgress.beginTask('Validating timezone boundaries')
    loadFinalZonesIntoMemory()
    if (argv.skip_validation) {
      console.warn('WARNING: Skipping validation!')
      cb()
    } else {
      validateTimezoneBoundaries(cb)
    }
  }],
  create1970zones: ['validateZones', (results, cb) => {
    if (argv.skip_1970_zones) {
      overallProgress.beginTask('WARNING: Skipping creation of 1970 zones!')
      cb()
      return
    }
    overallProgress.beginTask('Creating 1970 timezone boundaries')
    makeDerivedTimezoneBoundaries('1970', cb)
  }],
  createNowZones: ['validateZones', (results, cb) => {
    if (argv.skip_now_zones) {
      overallProgress.beginTask('WARNING: Skipping creation of now zones!')
      cb()
      return
    }
    overallProgress.beginTask('Creating now timezone boundaries')
    makeDerivedTimezoneBoundaries('now', cb)
  }],
  addOceans: ['validateZones', function (results, cb) {
    overallProgress.beginTask('Adding oceans')
    addOceans(cb)
  }],
  mergeZones: ['addOceans', 'create1970zones', 'createNowZones', function (results, cb) {
    overallProgress.beginTask('Merging zones')
    combineAndWriteZones(cb)
  }],
  mergeOSMZones: ['getOsmTzBoundaries', function (results, cb) {
    if (argv.skip_analyze_osm_tz_diffs) {
      overallProgress.beginTask('WARNING: Skipping merging of all OSM timezone relations for analysis!')
      cb()
    } else {
      overallProgress.beginTask('Merging osm zones')
      combineAndWriteOSMZones(cb)
    }
  }],
  zipGeoJsonFiles: ['mergeZones', function (results, cb) {
    if (argv.skip_zip) {
      overallProgress.beginTask('Skipping zip')
      return cb()
    }
    overallProgress.beginTask('Zipping geojson files')
    zipGeoJsonFiles(cb)
  }],
  makeShapefiles: ['mergeZones', function (results, cb) {
    if (argv.skip_shapefile) {
      overallProgress.beginTask('Skipping shapefile creation')
      return cb()
    }
    overallProgress.beginTask('Converting from geojson to shapefile')
    makeShapefiles(cb)
  }],
  makeOSMTimezoneShapefile: ['mergeOSMZones', function (results, cb) {
    if (argv.skip_analyze_osm_tz_diffs || argv.skip_shapefile) {
      overallProgress.beginTask('Skipping OSM zone shapefile creation')
      return cb()
    }
    makeShapefile(
      {
        jsonFile: path.join(workingDir, 'combined-osm-zones.json'),
        shapeFile: path.join(workingDir, 'combined-osm-zone-shapefile.shp'),
        shapeFileGlob: path.join(workingDir, 'combined-osm-zone-shapefile.*')
      },
      cb
    )
  }],
  makeListOfTimeZoneNames: function (cb) {
    overallProgress.beginTask('Writing timezone names to file')
    let zoneNames = Object.keys(zoneCfg)
    oceanZones.forEach(oceanZone => {
      zoneNames.push(oceanZone.tzid)
    })
    if (includedZones.length > 0) {
      zoneNames = zoneNames.filter(zoneName => includedZones.indexOf(zoneName) > -1)
    }
    if (excludedZones.length > 0) {
      zoneNames = zoneNames.filter(zoneName => excludedZones.indexOf(zoneName) === -1)
    }
    fs.writeFile(
      distDir + '/timezone-names.json',
      JSON.stringify(zoneNames),
      cb
    )
  },
  analyzeChangesFromLastRelease: ['downloadLastRelease', 'mergeZones', function (results, cb) {
    if (argv.skip_analyze_diffs) {
      overallProgress.beginTask('WARNING: Skipping analysis of changes from last release!')
      cb()
    } else {
      overallProgress.beginTask('Analyzing changes from last release')
      analyzeChangesFromLastRelease(cb)
    }
  }],
  cleanDownloadFolder: ['makeDistDir', 'getOsmBoundaries', 'makeOSMTimezoneShapefile', function (results, cb) {
    overallProgress.beginTask('cleanDownloadFolder')
    const downloadedFilenames = Object.keys(osmBoundarySources).map(name => `${name}.json`)
    fs.readdir(downloadsDir, (err, files) => {
      if (err) return cb(err)
      asynclib.each(
        files,
        (file, fileCb) => {
          if (downloadedFilenames.indexOf(file) === -1) {
            return fs.unlink(path.join(downloadsDir, file), fileCb)
          }
          fileCb()
        },
        cb
      )
    })
  }],
  zipInputData: ['cleanDownloadFolder', function (results, cb) {
    overallProgress.beginTask('Zipping up input data')
    assembleAndZipInputData(cb)
  }]
}

const overallProgress = new ProgressStats('Overall', Object.keys(autoScript).length)

asynclib.auto(autoScript, function (err, results) {
  console.log('done')
  if (err) {
    console.log('error!', err)
  }
})