/* eslint-disable
    camelcase,
    handle-callback-err,
    no-unused-vars,
*/
// TODO: This file was created by bulk-decaffeinate.
// Fix any style issues and re-enable lint.
/*
 * decaffeinate suggestions:
 * DS101: Remove unnecessary use of Array.from
 * DS102: Remove unnecessary code created because of implicit returns
 * DS103: Rewrite code to no longer use __guard__
 * DS205: Consider reworking code to avoid use of IIFEs
 * DS207: Consider shorter variations of null checks
 * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
 */
let fiveMinutes, UpdatesManager
const MongoManager = require('./MongoManager')
const PackManager = require('./PackManager')
const RedisManager = require('./RedisManager')
const UpdateCompressor = require('./UpdateCompressor')
const LockManager = require('./LockManager')
const WebApiManager = require('./WebApiManager')
const UpdateTrimmer = require('./UpdateTrimmer')
const logger = require('logger-sharelatex')
const async = require('async')
const _ = require('underscore')
const Settings = require('settings-sharelatex')
const keys = Settings.redis.lock.key_schema

module.exports = UpdatesManager = {
  compressAndSaveRawUpdates(
    project_id,
    doc_id,
    rawUpdates,
    temporary,
    callback
  ) {
    let i
    if (callback == null) {
      callback = function (error) {}
    }
    const { length } = rawUpdates
    if (length === 0) {
      return callback()
    }

    // check that ops are in the correct order
    for (i = 0; i < rawUpdates.length; i++) {
      const op = rawUpdates[i]
      if (i > 0) {
        const thisVersion = op != null ? op.v : undefined
        const prevVersion = __guard__(rawUpdates[i - 1], (x) => x.v)
        if (!(prevVersion < thisVersion)) {
          logger.error(
            {
              project_id,
              doc_id,
              rawUpdates,
              temporary,
              thisVersion,
              prevVersion
            },
            'op versions out of order'
          )
        }
      }
    }

    // FIXME: we no longer need the lastCompressedUpdate, so change functions not to need it
    // CORRECTION:  we do use it to log the time in case of error
    return MongoManager.peekLastCompressedUpdate(doc_id, function (
      error,
      lastCompressedUpdate,
      lastVersion
    ) {
      // lastCompressedUpdate is the most recent update in Mongo, and
      // lastVersion is its sharejs version number.
      //
      // The peekLastCompressedUpdate method may pass the update back
      // as 'null' (for example if the previous compressed update has
      // been archived).  In this case it can still pass back the
      // lastVersion from the update to allow us to check consistency.
      let op
      if (error != null) {
        return callback(error)
      }

      // Ensure that raw updates start where lastVersion left off
      if (lastVersion != null) {
        const discardedUpdates = []
        rawUpdates = rawUpdates.slice(0)
        while (rawUpdates[0] != null && rawUpdates[0].v <= lastVersion) {
          discardedUpdates.push(rawUpdates.shift())
        }
        if (discardedUpdates.length) {
          logger.error(
            { project_id, doc_id, discardedUpdates, temporary, lastVersion },
            'discarded updates already present'
          )
        }

        if (rawUpdates[0] != null && rawUpdates[0].v !== lastVersion + 1) {
          const ts = __guard__(
            lastCompressedUpdate != null
              ? lastCompressedUpdate.meta
              : undefined,
            (x1) => x1.end_ts
          )
          const last_timestamp = ts != null ? new Date(ts) : 'unknown time'
          error = new Error(
            `Tried to apply raw op at version ${rawUpdates[0].v} to last compressed update with version ${lastVersion} from ${last_timestamp}`
          )
          logger.error(
            {
              err: error,
              doc_id,
              project_id,
              prev_end_ts: ts,
              temporary,
              lastCompressedUpdate
            },
            'inconsistent doc versions'
          )
          if (
            (Settings.trackchanges != null
              ? Settings.trackchanges.continueOnError
              : undefined) &&
            rawUpdates[0].v > lastVersion + 1
          ) {
            // we have lost some ops - continue to write into the database, we can't recover at this point
            lastCompressedUpdate = null
          } else {
            return callback(error)
          }
        }
      }

      if (rawUpdates.length === 0) {
        return callback()
      }

      // some old large ops in redis need to be rejected, they predate
      // the size limit that now prevents them going through the system
      const REJECT_LARGE_OP_SIZE = 4 * 1024 * 1024
      for (var rawUpdate of Array.from(rawUpdates)) {
        const opSizes = (() => {
          const result = []
          for (op of Array.from(
            (rawUpdate != null ? rawUpdate.op : undefined) || []
          )) {
            result.push(
              (op.i != null ? op.i.length : undefined) ||
                (op.d != null ? op.d.length : undefined)
            )
          }
          return result
        })()
        const size = _.max(opSizes)
        if (size > REJECT_LARGE_OP_SIZE) {
          error = new Error(
            `dropped op exceeding maximum allowed size of ${REJECT_LARGE_OP_SIZE}`
          )
          logger.error(
            { err: error, doc_id, project_id, size, rawUpdate },
            'dropped op - too big'
          )
          rawUpdate.op = []
        }
      }

      const compressedUpdates = UpdateCompressor.compressRawUpdates(
        null,
        rawUpdates
      )
      return PackManager.insertCompressedUpdates(
        project_id,
        doc_id,
        lastCompressedUpdate,
        compressedUpdates,
        temporary,
        function (error, result) {
          if (error != null) {
            return callback(error)
          }
          if (result != null) {
            logger.log(
              {
                project_id,
                doc_id,
                orig_v:
                  lastCompressedUpdate != null
                    ? lastCompressedUpdate.v
                    : undefined,
                new_v: result.v
              },
              'inserted updates into pack'
            )
          }
          return callback()
        }
      )
    })
  },

  // Check whether the updates are temporary (per-project property)
  _prepareProjectForUpdates(project_id, callback) {
    if (callback == null) {
      callback = function (error, temporary) {}
    }
    return UpdateTrimmer.shouldTrimUpdates(project_id, function (
      error,
      temporary
    ) {
      if (error != null) {
        return callback(error)
      }
      return callback(null, temporary)
    })
  },

  // Check for project id on document history (per-document property)
  _prepareDocForUpdates(project_id, doc_id, callback) {
    if (callback == null) {
      callback = function (error) {}
    }
    return MongoManager.backportProjectId(project_id, doc_id, function (error) {
      if (error != null) {
        return callback(error)
      }
      return callback(null)
    })
  },

  // Apply updates for specific project/doc after preparing at project and doc level
  REDIS_READ_BATCH_SIZE: 100,
  processUncompressedUpdates(project_id, doc_id, temporary, callback) {
    // get the updates as strings from redis (so we can delete them after they are applied)
    if (callback == null) {
      callback = function (error) {}
    }
    return RedisManager.getOldestDocUpdates(
      doc_id,
      UpdatesManager.REDIS_READ_BATCH_SIZE,
      function (error, docUpdates) {
        if (error != null) {
          return callback(error)
        }
        const { length } = docUpdates
        // parse the redis strings into ShareJs updates
        return RedisManager.expandDocUpdates(docUpdates, function (
          error,
          rawUpdates
        ) {
          if (error != null) {
            logger.err(
              { project_id, doc_id, docUpdates },
              'failed to parse docUpdates'
            )
            return callback(error)
          }
          logger.log(
            { project_id, doc_id, rawUpdates },
            'retrieved raw updates from redis'
          )
          return UpdatesManager.compressAndSaveRawUpdates(
            project_id,
            doc_id,
            rawUpdates,
            temporary,
            function (error) {
              if (error != null) {
                return callback(error)
              }
              logger.log(
                { project_id, doc_id },
                'compressed and saved doc updates'
              )
              // delete the applied updates from redis
              return RedisManager.deleteAppliedDocUpdates(
                project_id,
                doc_id,
                docUpdates,
                function (error) {
                  if (error != null) {
                    return callback(error)
                  }
                  if (length === UpdatesManager.REDIS_READ_BATCH_SIZE) {
                    // There might be more updates
                    logger.log(
                      { project_id, doc_id },
                      'continuing processing updates'
                    )
                    return setTimeout(
                      () =>
                        UpdatesManager.processUncompressedUpdates(
                          project_id,
                          doc_id,
                          temporary,
                          callback
                        ),
                      0
                    )
                  } else {
                    logger.log(
                      { project_id, doc_id },
                      'all raw updates processed'
                    )
                    return callback()
                  }
                }
              )
            }
          )
        })
      }
    )
  },

  // Process updates for a doc when we flush it individually
  processUncompressedUpdatesWithLock(project_id, doc_id, callback) {
    if (callback == null) {
      callback = function (error) {}
    }
    return UpdatesManager._prepareProjectForUpdates(project_id, function (
      error,
      temporary
    ) {
      if (error != null) {
        return callback(error)
      }
      return UpdatesManager._processUncompressedUpdatesForDocWithLock(
        project_id,
        doc_id,
        temporary,
        callback
      )
    })
  },

  // Process updates for a doc when the whole project is flushed (internal method)
  _processUncompressedUpdatesForDocWithLock(
    project_id,
    doc_id,
    temporary,
    callback
  ) {
    if (callback == null) {
      callback = function (error) {}
    }
    return UpdatesManager._prepareDocForUpdates(project_id, doc_id, function (
      error
    ) {
      if (error != null) {
        return callback(error)
      }
      return LockManager.runWithLock(
        keys.historyLock({ doc_id }),
        (releaseLock) =>
          UpdatesManager.processUncompressedUpdates(
            project_id,
            doc_id,
            temporary,
            releaseLock
          ),
        callback
      )
    })
  },

  // Process all updates for a project, only check project-level information once
  processUncompressedUpdatesForProject(project_id, callback) {
    if (callback == null) {
      callback = function (error) {}
    }
    return RedisManager.getDocIdsWithHistoryOps(project_id, function (
      error,
      doc_ids
    ) {
      if (error != null) {
        return callback(error)
      }
      return UpdatesManager._prepareProjectForUpdates(project_id, function (
        error,
        temporary
      ) {
        const jobs = []
        for (const doc_id of Array.from(doc_ids)) {
          ;((doc_id) =>
            jobs.push((cb) =>
              UpdatesManager._processUncompressedUpdatesForDocWithLock(
                project_id,
                doc_id,
                temporary,
                cb
              )
            ))(doc_id)
        }
        return async.parallelLimit(jobs, 5, callback)
      })
    })
  },

  // flush all outstanding changes
  flushAll(limit, callback) {
    if (callback == null) {
      callback = function (error, result) {}
    }
    return RedisManager.getProjectIdsWithHistoryOps(function (
      error,
      project_ids
    ) {
      let project_id
      if (error != null) {
        return callback(error)
      }
      logger.log(
        {
          count: project_ids != null ? project_ids.length : undefined,
          project_ids
        },
        'found projects'
      )
      const jobs = []
      project_ids = _.shuffle(project_ids) // randomise to avoid hitting same projects each time
      const selectedProjects =
        limit < 0 ? project_ids : project_ids.slice(0, limit)
      for (project_id of Array.from(selectedProjects)) {
        ;((project_id) =>
          jobs.push((cb) =>
            UpdatesManager.processUncompressedUpdatesForProject(
              project_id,
              (err) => cb(null, { failed: err != null, project_id })
            )
          ))(project_id)
      }
      return async.series(jobs, function (error, result) {
        let x
        if (error != null) {
          return callback(error)
        }
        const failedProjects = (() => {
          const result1 = []
          for (x of Array.from(result)) {
            if (x.failed) {
              result1.push(x.project_id)
            }
          }
          return result1
        })()
        const succeededProjects = (() => {
          const result2 = []
          for (x of Array.from(result)) {
            if (!x.failed) {
              result2.push(x.project_id)
            }
          }
          return result2
        })()
        return callback(null, {
          failed: failedProjects,
          succeeded: succeededProjects,
          all: project_ids
        })
      })
    })
  },

  getDanglingUpdates(callback) {
    if (callback == null) {
      callback = function (error, doc_ids) {}
    }
    return RedisManager.getAllDocIdsWithHistoryOps(function (
      error,
      all_doc_ids
    ) {
      if (error != null) {
        return callback(error)
      }
      return RedisManager.getProjectIdsWithHistoryOps(function (
        error,
        all_project_ids
      ) {
        if (error != null) {
          return callback(error)
        }
        // function to get doc_ids for each project
        const task = (cb) =>
          async.concatSeries(
            all_project_ids,
            RedisManager.getDocIdsWithHistoryOps,
            cb
          )
        // find the dangling doc ids
        return task(function (error, project_doc_ids) {
          const dangling_doc_ids = _.difference(all_doc_ids, project_doc_ids)
          logger.log(
            { all_doc_ids, all_project_ids, project_doc_ids, dangling_doc_ids },
            'checking for dangling doc ids'
          )
          return callback(null, dangling_doc_ids)
        })
      })
    })
  },

  getDocUpdates(project_id, doc_id, options, callback) {
    if (options == null) {
      options = {}
    }
    if (callback == null) {
      callback = function (error, updates) {}
    }
    return UpdatesManager.processUncompressedUpdatesWithLock(
      project_id,
      doc_id,
      function (error) {
        if (error != null) {
          return callback(error)
        }
        // console.log "options", options
        return PackManager.getOpsByVersionRange(
          project_id,
          doc_id,
          options.from,
          options.to,
          function (error, updates) {
            if (error != null) {
              return callback(error)
            }
            return callback(null, updates)
          }
        )
      }
    )
  },

  getDocUpdatesWithUserInfo(project_id, doc_id, options, callback) {
    if (options == null) {
      options = {}
    }
    if (callback == null) {
      callback = function (error, updates) {}
    }
    return UpdatesManager.getDocUpdates(project_id, doc_id, options, function (
      error,
      updates
    ) {
      if (error != null) {
        return callback(error)
      }
      return UpdatesManager.fillUserInfo(updates, function (error, updates) {
        if (error != null) {
          return callback(error)
        }
        return callback(null, updates)
      })
    })
  },

  getSummarizedProjectUpdates(project_id, options, callback) {
    if (options == null) {
      options = {}
    }
    if (callback == null) {
      callback = function (error, updates) {}
    }
    if (!options.min_count) {
      options.min_count = 25
    }
    let summarizedUpdates = []
    const { before } = options
    let nextBeforeTimestamp = null
    return UpdatesManager.processUncompressedUpdatesForProject(
      project_id,
      function (error) {
        if (error != null) {
          return callback(error)
        }
        return PackManager.makeProjectIterator(project_id, before, function (
          err,
          iterator
        ) {
          if (err != null) {
            return callback(err)
          }
          // repeatedly get updates and pass them through the summariser to get an final output with user info
          return async.whilst(
            () =>
              // console.log "checking iterator.done", iterator.done()
              summarizedUpdates.length < options.min_count && !iterator.done(),

            (cb) =>
              iterator.next(function (err, partialUpdates) {
                if (err != null) {
                  return callback(err)
                }
                // logger.log {partialUpdates}, 'got partialUpdates'
                if (partialUpdates.length === 0) {
                  return cb()
                } // # FIXME should try to avoid this happening
                nextBeforeTimestamp =
                  partialUpdates[partialUpdates.length - 1].meta.end_ts
                // add the updates to the summary list
                summarizedUpdates = UpdatesManager._summarizeUpdates(
                  partialUpdates,
                  summarizedUpdates
                )
                return cb()
              }),

            () =>
              // finally done all updates
              // console.log 'summarized Updates', summarizedUpdates
              UpdatesManager.fillSummarizedUserInfo(
                summarizedUpdates,
                function (err, results) {
                  if (err != null) {
                    return callback(err)
                  }
                  return callback(
                    null,
                    results,
                    !iterator.done() ? nextBeforeTimestamp : undefined
                  )
                }
              )
          )
        })
      }
    )
  },

  exportProject(projectId, consumer) {
    // Flush anything before collecting updates.
    UpdatesManager.processUncompressedUpdatesForProject(projectId, (err) => {
      if (err) return consumer(err)

      // Fetch all the packs.
      const before = undefined
      PackManager.makeProjectIterator(projectId, before, (err, iterator) => {
        if (err) return consumer(err)

        const accumulatedUserIds = new Set()

        async.whilst(
          () => !iterator.done(),

          (cb) =>
            iterator.next((err, updatesFromASinglePack) => {
              if (err) return cb(err)

              if (updatesFromASinglePack.length === 0) {
                // This should not happen when `iterator.done() == false`.
                // Emitting an empty array would signal the consumer the final
                //  call.
                return cb()
              }
              updatesFromASinglePack.forEach((update) => {
                accumulatedUserIds.add(
                  // Super defensive access on update details.
                  String(update && update.meta && update.meta.user_id)
                )
              })
              // Emit updates and wait for the consumer.
              consumer(null, { updates: updatesFromASinglePack }, cb)
            }),

          (err) => {
            if (err) return consumer(err)

            // Adding undefined can happen for broken updates.
            accumulatedUserIds.delete('undefined')

            consumer(null, {
              updates: [],
              userIds: Array.from(accumulatedUserIds).sort()
            })
          }
        )
      })
    })
  },

  fetchUserInfo(users, callback) {
    if (callback == null) {
      callback = function (error, fetchedUserInfo) {}
    }
    const jobs = []
    const fetchedUserInfo = {}
    for (const user_id in users) {
      ;((user_id) =>
        jobs.push((callback) =>
          WebApiManager.getUserInfo(user_id, function (error, userInfo) {
            if (error != null) {
              return callback(error)
            }
            fetchedUserInfo[user_id] = userInfo
            return callback()
          })
        ))(user_id)
    }

    return async.series(jobs, function (err) {
      if (err != null) {
        return callback(err)
      }
      return callback(null, fetchedUserInfo)
    })
  },

  fillUserInfo(updates, callback) {
    let update, user_id
    if (callback == null) {
      callback = function (error, updates) {}
    }
    const users = {}
    for (update of Array.from(updates)) {
      ;({ user_id } = update.meta)
      if (UpdatesManager._validUserId(user_id)) {
        users[user_id] = true
      }
    }

    return UpdatesManager.fetchUserInfo(users, function (
      error,
      fetchedUserInfo
    ) {
      if (error != null) {
        return callback(error)
      }
      for (update of Array.from(updates)) {
        ;({ user_id } = update.meta)
        delete update.meta.user_id
        if (UpdatesManager._validUserId(user_id)) {
          update.meta.user = fetchedUserInfo[user_id]
        }
      }
      return callback(null, updates)
    })
  },

  fillSummarizedUserInfo(updates, callback) {
    let update, user_id, user_ids
    if (callback == null) {
      callback = function (error, updates) {}
    }
    const users = {}
    for (update of Array.from(updates)) {
      user_ids = update.meta.user_ids || []
      for (user_id of Array.from(user_ids)) {
        if (UpdatesManager._validUserId(user_id)) {
          users[user_id] = true
        }
      }
    }

    return UpdatesManager.fetchUserInfo(users, function (
      error,
      fetchedUserInfo
    ) {
      if (error != null) {
        return callback(error)
      }
      for (update of Array.from(updates)) {
        user_ids = update.meta.user_ids || []
        update.meta.users = []
        delete update.meta.user_ids
        for (user_id of Array.from(user_ids)) {
          if (UpdatesManager._validUserId(user_id)) {
            update.meta.users.push(fetchedUserInfo[user_id])
          } else {
            update.meta.users.push(null)
          }
        }
      }
      return callback(null, updates)
    })
  },

  _validUserId(user_id) {
    if (user_id == null) {
      return false
    } else {
      return !!user_id.match(/^[a-f0-9]{24}$/)
    }
  },

  TIME_BETWEEN_DISTINCT_UPDATES: (fiveMinutes = 5 * 60 * 1000),
  SPLIT_ON_DELETE_SIZE: 16, // characters
  _summarizeUpdates(updates, existingSummarizedUpdates) {
    if (existingSummarizedUpdates == null) {
      existingSummarizedUpdates = []
    }
    const summarizedUpdates = existingSummarizedUpdates.slice()
    let previousUpdateWasBigDelete = false
    for (const update of Array.from(updates)) {
      var doc_id
      const earliestUpdate = summarizedUpdates[summarizedUpdates.length - 1]
      let shouldConcat = false

      // If a user inserts some text, then deletes a big chunk including that text,
      // the update we show might concat the insert and delete, and there will be no sign
      // of that insert having happened, or be able to restore to it (restoring after a big delete is common).
      // So, we split the summary on 'big' deletes. However, we've stepping backwards in time with
      // most recent changes considered first, so if this update is a big delete, we want to start
      // a new summarized update next timge, hence we monitor the previous update.
      if (previousUpdateWasBigDelete) {
        shouldConcat = false
      } else if (
        earliestUpdate &&
        earliestUpdate.meta.end_ts - update.meta.start_ts <
          this.TIME_BETWEEN_DISTINCT_UPDATES
      ) {
        // We're going backwards in time through the updates, so only combine if this update starts less than 5 minutes before
        // the end of current summarized block, so no block spans more than 5 minutes.
        shouldConcat = true
      }

      let isBigDelete = false
      for (const op of Array.from(update.op || [])) {
        if (op.d != null && op.d.length > this.SPLIT_ON_DELETE_SIZE) {
          isBigDelete = true
        }
      }

      previousUpdateWasBigDelete = isBigDelete

      if (shouldConcat) {
        // check if the user in this update is already present in the earliest update,
        // if not, add them to the users list of the earliest update
        earliestUpdate.meta.user_ids = _.union(earliestUpdate.meta.user_ids, [
          update.meta.user_id
        ])

        doc_id = update.doc_id.toString()
        const doc = earliestUpdate.docs[doc_id]
        if (doc != null) {
          doc.fromV = Math.min(doc.fromV, update.v)
          doc.toV = Math.max(doc.toV, update.v)
        } else {
          earliestUpdate.docs[doc_id] = {
            fromV: update.v,
            toV: update.v
          }
        }

        earliestUpdate.meta.start_ts = Math.min(
          earliestUpdate.meta.start_ts,
          update.meta.start_ts
        )
        earliestUpdate.meta.end_ts = Math.max(
          earliestUpdate.meta.end_ts,
          update.meta.end_ts
        )
      } else {
        const newUpdate = {
          meta: {
            user_ids: [],
            start_ts: update.meta.start_ts,
            end_ts: update.meta.end_ts
          },
          docs: {}
        }

        newUpdate.docs[update.doc_id.toString()] = {
          fromV: update.v,
          toV: update.v
        }
        newUpdate.meta.user_ids.push(update.meta.user_id)
        summarizedUpdates.push(newUpdate)
      }
    }

    return summarizedUpdates
  }
}

function __guard__(value, transform) {
  return typeof value !== 'undefined' && value !== null
    ? transform(value)
    : undefined
}