/**
* Copyright © 2019 code initially contributed by Orange SA, authors: Denis Barbaron - Licensed under the Apache license 2.0
**/

const _ = require('lodash')
const dbapi = require('../../../db/api')
const apiutil = require('../../../util/apiutil')
const lockutil = require('../../../util/lockutil')
const util = require('util')
const uuid = require('uuid')
const Promise = require('bluebird')
const usersapi = require('./users')

/* ---------------------------------- PRIVATE FUNCTIONS --------------------------------- */

function groupApiWrapper(email, fn, req, res) {
  dbapi.loadUser(email).then(function(user) {
    if (!user) {
      apiutil.respond(res, 404, 'Not Found (user)')
    }
    else {
      req.user = user
      fn(req, res)
    }
  })
  .catch(function(err) {
    apiutil.internalError(res, 'Failed to wrap "%s": ', fn.name, err.stack)
  })
}

function getDevice(req, serial) {
  return dbapi.loadDeviceBySerial(serial).then(function(device) {
    if (!device) {
      throw new Error(`Device not found: ${serial}`)
    }
    return apiutil.filterDevice(req, device)
  })
}

function checkConflicts(id, devices, dates) {
  function computeConflicts(conflicts, liteGroup, otherGroup) {
    if (otherGroup.id !== liteGroup.id) {
      const devices = _.intersection(liteGroup.devices, otherGroup.devices)

      if (devices.length) {
        for (let liteGroupDate of liteGroup.dates) {
          for (let otherGroupDate of otherGroup.dates) {
            if (liteGroupDate.start < otherGroupDate.stop &&
                liteGroupDate.stop > otherGroupDate.start) {
              conflicts.push({
                devices: devices
              , date: {
                 start: new Date(
                   Math.max(liteGroupDate.start.getTime()
                 , otherGroupDate.start.getTime()))
               , stop: new Date(
                   Math.min(liteGroupDate.stop.getTime()
                 , otherGroupDate.stop.getTime()))
               }
              , group: otherGroup.name
              , owner: otherGroup.owner
              })
            }
          }
        }
      }
    }
  }

  return dbapi.getTransientGroups().then(function(groups) {
    const conflicts = []

    groups.forEach(function(otherGroup) {
      computeConflicts(
        conflicts
      , {id: id, devices: devices, dates: dates}
      , otherGroup)
    })
    return conflicts
  })
}

function checkSchedule(res, oldGroup, _class, email, repetitions, privilege, start, stop) {
  if (oldGroup && oldGroup.devices.length &&
      (apiutil.isOriginGroup(_class) && !apiutil.isOriginGroup(oldGroup.class) ||
       apiutil.isOriginGroup(oldGroup.class) && !apiutil.isOriginGroup(_class))) {
    return Promise.resolve(apiutil.respond(res, 403,
      'Forbidden (unauthorized class while device list is not empty)'))
  }
  if (apiutil.isAdminGroup(_class) && privilege === apiutil.USER) {
    return Promise.resolve(apiutil.respond(res, 403, 'Forbidden (unauthorized class)'))
  }
  if (isNaN(start.getTime())) {
    return Promise.resolve(apiutil.respond(res, 400, 'Bad Request (Invalid startTime format)'))
  }
  if (isNaN(stop.getTime())) {
    return Promise.resolve(apiutil.respond(res, 400, 'Bad Request (Invalid stopTime format)'))
  }
  if (start >= stop) {
    return Promise.resolve(
      apiutil.respond(res, 400, 'Bad Request (Invalid life time: startTime >= stopTime)'))
  }
  if ((stop - start) > apiutil.CLASS_DURATION[_class]) {
    return Promise.resolve(apiutil.respond(res, 400,
      'Bad Request (Invalid Life time & class combination: life time > class duration)'
    ))
  }
  switch(_class) {
    case apiutil.BOOKABLE:
    case apiutil.STANDARD:
    case apiutil.ONCE:
      if (repetitions !== 0) {
        return Promise.resolve(
          apiutil.respond(res, 400, 'Bad Request (Invalid class & repetitions combination)'))
      }
      break
    default:
      if (repetitions === 0) {
        return Promise.resolve(
          apiutil.respond(res, 400, 'Bad Request (Invalid class & repetitions combination)'))
      }
      break
  }

  return dbapi.loadUser(email).then(function(owner) {
    if (repetitions > owner.groups.quotas.repetitions) {
      return apiutil.respond(res, 400, 'Bad Request (Invalid repetitions value)')
    }
    return true
  })
}

/* ---------------------------------- PUBLIC FUNCTIONS ------------------------------------- */

function addGroupDevices(req, res) {
  const id = req.swagger.params.id.value
  const serials = apiutil.getBodyParameter(req.body, 'serials')
  const target = apiutil.getQueryParameter(req.swagger.params.redirected) ? 'device' : 'devices'
  const lock = {}
  let email = null

  function addGroupDevice(group, serial) {
    const lock = {}

    return dbapi.lockBookableDevice(req.user.groups.subscribed, serial).then(function(stats) {
      if (!stats.replaced) {
        return apiutil.lightComputeStats(res, stats)
      }
      lock.device = stats.changes[0].new_val

      return dbapi.lockGroup(lock.device.group.origin).then(function(stats) {
        if (!stats.replaced) {
          return apiutil.lightComputeStats(res, stats)
        }
        lock.group = {id: lock.device.group.origin}

        return checkConflicts(id, [serial], group.dates).then(function(conflicts) {
          return conflicts.length ?
            Promise.reject(conflicts) :
            dbapi.addGroupDevices(group, [serial])
        })
      })
      .finally(function() {
        lockutil.unlockGroup(lock)
      })
    })
    .finally(function() {
      lockutil.unlockDevice(lock)
    })
  }

  function _addGroupDevices(lockedGroup, serials) {
    let results = []
    let group = lockedGroup

    return Promise.each(serials, function(serial) {
      return addGroupDevice(group, serial).then(function(result) {
        results.push(result)
          if (result.hasOwnProperty('id')) {
            group = result
          }
      })
    })
    .then(function() {
      results = _.without(results, 'unchanged')
      if (!results.length) {
        apiutil.respond(res, 200, `Unchanged (group ${target})`, {group: {}})
      }
      else {
        results = _.without(results, 'not found')
        if (!results.length) {
          apiutil.respond(res, 404, `Not Found (group ${target})`)
        }
        else {
          apiutil.respond(res, 200, `Added (group ${target})`
          , {group: apiutil.publishGroup(results[results.length - 1])})
        }
      }
    })
    .catch(function(err) {
      if (err === 'quota is reached') {
        apiutil.respond(res, 403, 'Forbidden (groups duration quota is reached)')
      }
      else if (Array.isArray(err)) {
        apiutil.respond(res, 409, 'Conflicts Information', {conflicts: err})
      }
      else if (err !== 'busy') {
        throw err
      }
    })
  }

  lockutil.lockGroup(req, res, lock).then(function(lockingSuccessed) {
    if (lockingSuccessed) {
      let group = lock.group

      if (req.user.privilege === apiutil.ADMIN && req.user.email !== group.owner.email) {
        email = group.owner.email
        return false
      }
      if (apiutil.isOriginGroup(group.class)) {
        return apiutil.respond(res, 400, 'Bad Request (use admin API for bookable/standard groups)')
      }

      return (function() {
        if (typeof serials === 'undefined') {
          return dbapi.loadBookableDevices(req.user.groups.subscribed).then(function(devices) {
            const serials = []

            devices.forEach(function(device) {
              if (group.devices.indexOf(device.serial) < 0) {
                serials.push(device.serial)
              }
            })
            return _addGroupDevices(group, serials)
          })
        }
        else {
          return _addGroupDevices(
            group
          , _.difference(
              _.without(serials.split(','), '')
            , group.devices)
          )
        }
      })()
    }
    return false
  })
  .catch(function(err) {
    apiutil.internalError(res, `Failed to add group ${target}: `, err.stack)
  })
  .finally(function() {
    lockutil.unlockGroup(lock)
    if (email) {
      groupApiWrapper(email, addGroupDevices, req, res)
    }
  })
}

function addGroupDevice(req, res) {
  apiutil.redirectApiWrapper('serial', addGroupDevices, req, res)
}

function removeGroupDevices(req, res) {
  const serials = apiutil.getBodyParameter(req.body, 'serials')
  const target = apiutil.getQueryParameter(req.swagger.params.redirected) ? 'device' : 'devices'
  const lock = {}

  lockutil.lockGroup(req, res, lock).then(function(lockingSuccessed) {
    if (lockingSuccessed) {
      const group = lock.group

      if (apiutil.isOriginGroup(group.class)) {
        return apiutil.respond(res, 400, 'Bad Request (use admin API for bookable/standard groups)')
      }
      let serialsToRemove = group.devices

      if (typeof serials !== 'undefined') {
        serialsToRemove = _.without(serials.split(','), '')
      }
      if (!serialsToRemove.length) {
        return apiutil.respond(res, 200, `Unchanged (group ${target})`, {group: {}})
      }
      serialsToRemove = _.intersection(serialsToRemove, group.devices)
      if (!serialsToRemove.length) {
        return apiutil.respond(res, 404, `Not Found (group ${target})`)
      }
      return dbapi.removeGroupDevices(group, serialsToRemove).then(function(group) {
        apiutil.respond(res, 200, `Removed (group ${target})`, {group: apiutil.publishGroup(group)})
      })
    }
    return false
  })
  .catch(function(err) {
    apiutil.internalError(res, `Failed to remove group ${target}: `, err.stack)
  })
  .finally(function() {
    lockutil.unlockGroup(lock)
  })
}

function removeGroupDevice(req, res) {
  apiutil.redirectApiWrapper('serial', removeGroupDevices, req, res)
}

function getGroupDevice(req, res) {
  const id = req.swagger.params.id.value
  const serial = req.swagger.params.serial.value

  dbapi.getUserGroup(req.user.email, id).then(function(group) {
    if (!group) {
      apiutil.respond(res, 404, 'Not Found (group)')
    }
    else if (group.devices.indexOf(serial) < 0) {
      apiutil.respond(res, 404, 'Not Found (device)')
    }
    else {
      getDevice(req, serial).then(function(device) {
        apiutil.respond(res, 200, 'Device Information', {device: device})
      })
    }
  })
  .catch(function(err) {
    apiutil.internalError(res, 'Failed to get group device: ', err.stack)
  })
}

function getGroupUser(req, res) {
  const id = req.swagger.params.id.value
  const email = req.swagger.params.email.value

  dbapi.getUserGroup(req.user.email, id).then(function(group) {
    if (!group) {
      apiutil.respond(res, 404, 'Not Found (group)')
    }
    else if (group.users.indexOf(email) < 0) {
      apiutil.respond(res, 404, 'Not Found (user)')
    }
    else {
      usersapi.getUserByEmail(req, res)
    }
  })
  .catch(function(err) {
    apiutil.internalError(res, 'Failed to get group user: ', err.stack)
  })
}

function getGroupUsers(req, res) {
  const id = req.swagger.params.id.value

  dbapi.getUserGroup(req.user.email, id).then(function(group) {
    if (!group) {
      apiutil.respond(res, 404, 'Not Found (group)')
    }
    else {
      Promise.map(group.users, function(email) {
        return usersapi.getUserInfo(req, email).then(function(user) {
          return user || Promise.reject(`Group user not found: ${email}`)
        })
      })
      .then(function(users) {
        apiutil.respond(res, 200, 'Users Information', {users: users})
      })
    }
  })
  .catch(function(err) {
    apiutil.internalError(res, 'Failed to get group users: ', err.stack)
  })
}

function removeGroupUsers(req, res) {
  const id = req.swagger.params.id.value
  const emails = apiutil.getBodyParameter(req.body, 'emails')
  const target = apiutil.getQueryParameter(req.swagger.params.redirected) ? 'user' : 'users'
  const lock = {}

  function removeGroupUser(email, group, rootGroup) {
    if (group.users.indexOf(email) < 0) {
      return Promise.resolve('not found')
    }
    if (email === rootGroup.owner.email || email === group.owner.email) {
      return Promise.resolve('forbidden')
    }
    const lock = {}

    return dbapi.lockUser(email).then(function(stats) {
      if (!stats.replaced) {
        return apiutil.lightComputeStats(res, stats)
      }
      lock.user = stats.changes[0].new_val

      return dbapi.isRemoveGroupUserAllowed(email, group)
        .then(function(isAllowed) {
          return isAllowed ? dbapi.removeGroupUser(id, email) : 'forbidden'
        })
    })
    .finally(function() {
      lockutil.unlockUser(lock)
    })
  }

  lockutil.lockGroup(req, res, lock).then(function(lockingSuccessed) {
    if (lockingSuccessed) {
      const group = lock.group

      return dbapi.getRootGroup().then(function(rootGroup) {
        let emailsToRemove = group.users
        let results = []

        if (typeof emails !== 'undefined') {
          emailsToRemove = _.without(emails.split(','), '')
        }
        return Promise.each(emailsToRemove, function(email) {
          return removeGroupUser(email, group, rootGroup).then(function(result) {
            results.push(result)
          })
        })
        .then(function() {
          if (!results.length) {
            return apiutil.respond(res, 200, `Unchanged (group ${target})`, {group: {}})
          }
          results = _.without(results, 'not found')
          if (!results.length) {
            return apiutil.respond(res, 404, `Not Found (group ${target})`)
          }
          if (!_.without(results, 'forbidden').length) {
            return apiutil.respond(res, 403, `Forbidden (group ${target})`)
          }
          return dbapi.getGroup(id).then(function(group) {
            apiutil.respond(res, 200, `Removed (group ${target})`, {
              group: apiutil.publishGroup(group)})
          })
        })
      })
      .catch(function(err) {
        if (err !== 'busy') {
          throw err
        }
      })
    }
    return false
  })
  .catch(function(err) {
    apiutil.internalError(res, `Failed to remove group ${target}: `, err.stack)
  })
  .finally(function() {
    lockutil.unlockGroup(lock)
  })
}

function removeGroupUser(req, res) {
  apiutil.redirectApiWrapper('email', removeGroupUsers, req, res)
}

function addGroupUsers(req, res) {
  const id = req.swagger.params.id.value
  const emails = apiutil.getBodyParameter(req.body, 'emails')
  const target = apiutil.getQueryParameter(req.swagger.params.redirected) ? 'user' : 'users'
  const lock = {}

  function addGroupUser(email) {
    const lock = {}

    return dbapi.lockUser(email).then(function(stats) {
      if (!stats.replaced) {
        return apiutil.lightComputeStats(res, stats)
      }
      lock.user = stats.changes[0].new_val

      return dbapi.addGroupUser(id, email)
    })
    .finally(function() {
      lockutil.unlockUser(lock)
    })
  }

  function _addGroupUsers(emails) {
    let results = []

    return Promise.each(emails, function(email) {
      return addGroupUser(email).then(function(result) {
        results.push(result)
      })
    })
    .then(function() {
      results = _.without(results, 'unchanged')
      if (!results.length) {
        return apiutil.respond(res, 200, `Unchanged (group ${target})`, {group: {}})
      }
      if (!_.without(results, 'not found').length) {
        return apiutil.respond(res, 404, `Not Found (group ${target})`)
      }
      return dbapi.getGroup(id).then(function(group) {
        apiutil.respond(res, 200, `Added (group ${target})`, {group: apiutil.publishGroup(group)})
      })
    })
    .catch(function(err) {
      if (err !== 'busy') {
        throw err
      }
    })
  }

  lockutil.lockGroup(req, res, lock).then(function(lockingSuccessed) {
    if (!lockingSuccessed) {
      return false
    }
    const group = lock.group

    return (function() {
      if (typeof emails === 'undefined') {
        return dbapi.getUsers().then(function(users) {
          const emails = []

          users.forEach(function(user) {
            if (group.users.indexOf(user.email) < 0) {
              emails.push(user.email)
            }
          })
          return _addGroupUsers(emails)
        })
      }
      else {
        return _addGroupUsers(
          _.difference(
            _.without(emails.split(','), '')
          , group.users)
        )
      }
    })()
  })
  .catch(function(err) {
    apiutil.internalError(res, `Failed to add group ${target}: `, err.stack)
  })
  .finally(function() {
    lockutil.unlockGroup(lock)
  })
}

function addGroupUser(req, res) {
  apiutil.redirectApiWrapper('email', addGroupUsers, req, res)
}

function getGroup(req, res) {
  const id = req.swagger.params.id.value
  const fields = req.swagger.params.fields.value

  dbapi.getUserGroup(req.user.email, id).then(function(group) {
    if (!group) {
      apiutil.respond(res, 404, 'Not Found (group)')
      return
    }
    let publishedGroup = apiutil.publishGroup(group)

    if (fields) {
       publishedGroup = _.pick(publishedGroup, fields.split(','))
    }
    apiutil.respond(res, 200, 'Group Information', {group: publishedGroup})
  })
  .catch(function(err) {
    apiutil.internalError(res, 'Failed to get group: ', err.stack)
  })
}

function getGroups(req, res) {
  const fields = req.swagger.params.fields.value
  const owner = req.swagger.params.owner.value
  let getGenericGroups

  switch(owner) {
    case true:
      getGenericGroups = dbapi.getOwnerGroups
      break
    case false:
      getGenericGroups = dbapi.getOnlyUserGroups
      break
    default:
      getGenericGroups = dbapi.getUserGroups
  }
  getGenericGroups(req.user.email).then(function(groups) {
    return apiutil.respond(res, 200, 'Groups Information', {
      groups: groups.map(function(group) {
        if (fields) {
          return _.pick(apiutil.publishGroup(group), fields.split(','))
        }
        return apiutil.publishGroup(group)
      })
    })
  })
  .catch(function(err) {
    apiutil.internalError(res, 'Failed to get groups: ', err.stack)
  })
}

function createGroup(req, res) {
  const _class = typeof req.body.class === 'undefined' ? apiutil.ONCE : req.body.class
  const repetitions =
    apiutil.isOriginGroup(_class) || typeof req.body.repetitions === 'undefined' ?
      0 :
      req.body.repetitions
  const now = Date.now()
  const start =
    apiutil.isOriginGroup(_class) ?
      new Date(now) :
      new Date(req.body.startTime || now)
  const stop =
    apiutil.isOriginGroup(_class) ?
      new Date(now + apiutil.ONE_YEAR) :
      new Date(req.body.stopTime || now + apiutil.ONE_HOUR)

  checkSchedule(res, null, _class, req.user.email, repetitions, req.user.privilege,
    start, stop).then(function(checkingSuccessed) {
    if (!checkingSuccessed) {
      return
    }
    const name =
      typeof req.body.name === 'undefined' ?
        'New_' + util.format('%s', uuid.v4()).replace(/-/g, '') :
        req.body.name
    const state =
      apiutil.isOriginGroup(_class) || typeof req.body.state === 'undefined' ?
        apiutil.READY :
        req.body.state
    const isActive = state === apiutil.READY && apiutil.isOriginGroup(_class)
    const duration = 0
    const dates = apiutil.computeGroupDates({start: start, stop: stop}, _class, repetitions)

    dbapi.createUserGroup({
      name: name
    , owner: {
        email: req.user.email
      , name: req.user.name
      }
    , privilege: req.user.privilege
    , class: _class
    , repetitions: repetitions
    , isActive: isActive
    , dates: dates
    , duration: duration
    , state: state
    })
    .then(function(group) {
      if (group) {
        apiutil.respond(res, 201, 'Created', {group: apiutil.publishGroup(group)})
      }
      else {
        apiutil.respond(res, 403, 'Forbidden (groups number quota is reached)')
      }
    })
    .catch(function(err) {
      apiutil.internalError(res, 'Failed to create group: ', err.stack)
    })
  })
}

function deleteGroups(req, res) {
  const ids = apiutil.getBodyParameter(req.body, 'ids')
  const target = apiutil.getQueryParameter(req.swagger.params.redirected) ? 'group' : 'groups'

  function removeGroup(id) {
    const lock = {}

    return dbapi.lockGroupByOwner(req.user.email, id).then(function(stats) {
      if (!stats.replaced) {
        return apiutil.lightComputeStats(res, stats)
      }
      const group = lock.group = stats.changes[0].new_val

      if (group.privilege === apiutil.ROOT) {
        return 'forbidden'
      }
      if (group.class === apiutil.BOOKABLE) {
        return Promise.each(group.devices, function(serial) {
          return dbapi.isDeviceBooked(serial)
            .then(function(isBooked) {
              return isBooked ? Promise.reject('booked') : true
            })
        })
        .then(function() {
          return dbapi.deleteUserGroup(id)
        })
        .catch(function(err) {
          if (err !== 'booked') {
            throw err
          }
          return 'forbidden'
        })
      }
      else {
        return dbapi.deleteUserGroup(id)
      }
    })
    .finally(function() {
      lockutil.unlockGroup(lock)
    })
  }

  function removeGroups(ids) {
    let results = []

    return Promise.each(ids, function(id) {
      return removeGroup(id).then(function(result) {
        results.push(result)
      })
    })
    .then(function() {
      if (!results.length) {
        return apiutil.respond(res, 200, `Unchanged (${target})`)
      }
      results = _.without(results, 'not found')
      if (!results.length) {
        return apiutil.respond(res, 404, `Not Found (${target})`)
      }
      results = _.without(results, 'forbidden')
      if (!results.length) {
        return apiutil.respond(res, 403, `Forbidden (${target})`)
      }
      return apiutil.respond(res, 200, `Deleted (${target})`)
    })
    .catch(function(err) {
      if (err !== 'busy') {
        throw err
      }
    })
  }

  (function() {
    if (typeof ids === 'undefined') {
      return dbapi.getOwnerGroups(req.user.email).then(function(groups) {
        const ids = []

        groups.forEach(function(group) {
          if (group.privilege !== apiutil.ROOT) {
            ids.push(group.id)
          }
        })
        return removeGroups(ids)
      })
    }
    else {
      return removeGroups(_.without(ids.split(','), ''))
    }
  })()
  .catch(function(err) {
    apiutil.internalError(res, `Failed to delete ${target}: `, err.stack)
  })
}

function deleteGroup(req, res) {
  apiutil.redirectApiWrapper('id', deleteGroups, req, res)
}

function updateGroup(req, res) {
  const id = req.swagger.params.id.value
  const lock = {}

  function updateUserGroup(group, data) {
    return dbapi.updateUserGroup(group, data)
      .then(function(group) {
        if (group) {
          apiutil.respond(res, 200, 'Updated (group)', {group: apiutil.publishGroup(group)})
        }
        else {
          apiutil.respond(res, 403, 'Forbidden (groups duration quota is reached)')
        }
      })
  }

  lockutil.lockGroup(req, res, lock).then(function(lockingSuccessed) {
    if (!lockingSuccessed) {
      return false
    }
    const group = lock.group
    const _class = typeof req.body.class === 'undefined' ? group.class : req.body.class
    const name = typeof req.body.name === 'undefined' ? group.name : req.body.name
    const repetitions =
      typeof req.body.repetitions === 'undefined' ?
        group.repetitions :
        req.body.repetitions
    const start = new Date(req.body.startTime || group.dates[0].start)
    const stop = new Date(req.body.stopTime || group.dates[0].stop)
    let state, isActive

    if (apiutil.isOriginGroup(_class)) {
      state = apiutil.READY
      isActive = true
    }
    else {
      state = typeof req.body.state === 'undefined' ? apiutil.PENDING : req.body.state
      isActive = false
    }

    if (group.state === apiutil.READY && state === apiutil.PENDING) {
      return apiutil.respond(res, 403, 'Forbidden (group is ready)')
    }

    return checkSchedule(res, group, _class, group.owner.email, repetitions, group.privilege,
      start, stop).then(function(checkingSuccessed) {
      if (!checkingSuccessed) {
        return false
      }
      if (name === group.name &&
        start.toISOString() === group.dates[0].start.toISOString() &&
        stop.toISOString() === group.dates[0].stop.toISOString() &&
        state === group.state &&
        _class === group.class &&
        repetitions === group.repetitions) {
        return apiutil.respond(res, 200, 'Unchanged (group)', {group: {}})
      }
      const duration = group.devices.length * (stop - start) * (repetitions + 1)
      const dates = apiutil.computeGroupDates({start: start, stop: stop}, _class, repetitions)

      if (start < group.dates[0].start ||
        stop > group.dates[0].stop ||
        repetitions > group.repetitions ||
        _class !== group.class) {
        return checkConflicts(id, group.devices, dates)
          .then(function(conflicts) {
            if (!conflicts.length) {
              return updateUserGroup(group, {
                name: name
              , state: state
              , class: _class
              , isActive: isActive
              , repetitions: repetitions
              , dates: dates
              , duration: duration
              })
            }
            return apiutil.respond(res, 409, 'Conflicts Information', {conflicts: conflicts})
          })
      }
      return updateUserGroup(group, {
        name: name
      , state: state
      , class: _class
      , isActive: isActive
      , repetitions: repetitions
      , dates: dates
      , duration: duration
      })
    })
  })
  .catch(function(err) {
    apiutil.internalError(res, 'Failed to update group: ', err.stack)
  })
  .finally(function() {
    lockutil.unlockGroup(lock)
  })
}

function getGroupDevices(req, res) {
  const id = req.swagger.params.id.value
  const bookable = req.swagger.params.bookable.value

  dbapi.getUserGroup(req.user.email, id).then(function(group) {
    if (!group) {
      apiutil.respond(res, 404, 'Not Found (group)')
      return
    }
    if (bookable) {
      if (apiutil.isOriginGroup(group.class)) {
        apiutil.respond(res, 400, 'Bad Request (group is not transient)')
        return
      }
      if (req.user.privilege === apiutil.ADMIN && req.user.email !== group.owner.email) {
        groupApiWrapper(group.owner.email, getGroupDevices, req, res)
        return
      }
      dbapi.loadBookableDevices(req.user.groups.subscribed).then(function(devices) {
        Promise.map(devices, function(device) {
          return device.serial
        })
        .then(function(serials) {
          return checkConflicts(group.id, serials, group.dates)
            .then(function(conflicts) {
              let bookableSerials = serials

              conflicts.forEach(function(conflict) {
                bookableSerials = _.difference(bookableSerials, conflict.devices)
              })
              return bookableSerials
            })
        })
        .then(function(bookableSerials) {
          const deviceList = []

          devices.forEach(function(device) {
            if (bookableSerials.indexOf(device.serial) > -1) {
              deviceList.push(apiutil.filterDevice(req, device))
            }
          })
          apiutil.respond(res, 200, 'Devices Information', {devices: deviceList})
        })
      })
    }
    else {
      Promise.map(group.devices, function(serial) {
        return getDevice(req, serial)
      })
      .then(function(devices) {
        apiutil.respond(res, 200, 'Devices Information', {devices: devices})
      })
    }
  })
  .catch(function(err) {
    apiutil.internalError(res, 'Failed to get group devices: ', err.stack)
  })
}

module.exports = {
    createGroup: createGroup
  , updateGroup: updateGroup
  , deleteGroup: deleteGroup
  , deleteGroups: deleteGroups
  , getGroup: getGroup
  , getGroups: getGroups
  , getGroupUser: getGroupUser
  , getGroupUsers: getGroupUsers
  , addGroupUser: addGroupUser
  , addGroupUsers: addGroupUsers
  , removeGroupUser: removeGroupUser
  , removeGroupUsers: removeGroupUsers
  , getGroupDevice: getGroupDevice
  , getGroupDevices: getGroupDevices
  , addGroupDevice: addGroupDevice
  , addGroupDevices: addGroupDevices
  , removeGroupDevice: removeGroupDevice
  , removeGroupDevices: removeGroupDevices
}