/* eslint-disable
    camelcase,
    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
 * 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
 */
const request = require('request')
const Settings = require('settings-sharelatex')
const RedisManager = require('./RedisManager')
const { rclient } = RedisManager
const docUpdaterKeys = Settings.redis.documentupdater.key_schema
const async = require('async')
const ProjectManager = require('./ProjectManager')
const _ = require('lodash')
const logger = require('logger-sharelatex')

var ProjectFlusher = {
  // iterate over keys asynchronously using redis scan (non-blocking)
  // handle all the cluster nodes or single redis server
  _getKeys(pattern, limit, callback) {
    const nodes = (typeof rclient.nodes === 'function'
      ? rclient.nodes('master')
      : undefined) || [rclient]
    const doKeyLookupForNode = (node, cb) =>
      ProjectFlusher._getKeysFromNode(node, pattern, limit, cb)
    return async.concatSeries(nodes, doKeyLookupForNode, callback)
  },

  _getKeysFromNode(node, pattern, limit, callback) {
    if (limit == null) {
      limit = 1000
    }
    let cursor = 0 // redis iterator
    const keySet = {} // use hash to avoid duplicate results
    const batchSize = limit != null ? Math.min(limit, 1000) : 1000
    // scan over all keys looking for pattern
    var doIteration = (
      cb // avoid hitting redis too hard
    ) =>
      node.scan(cursor, 'MATCH', pattern, 'COUNT', batchSize, function (
        error,
        reply
      ) {
        let keys
        if (error != null) {
          return callback(error)
        }
        ;[cursor, keys] = Array.from(reply)
        for (const key of Array.from(keys)) {
          keySet[key] = true
        }
        keys = Object.keys(keySet)
        const noResults = cursor === '0' // redis returns string results not numeric
        const limitReached = limit != null && keys.length >= limit
        if (noResults || limitReached) {
          return callback(null, keys)
        } else {
          return setTimeout(doIteration, 10)
        }
      })
    return doIteration()
  },

  // extract ids from keys like DocsWithHistoryOps:57fd0b1f53a8396d22b2c24b
  // or docsInProject:{57fd0b1f53a8396d22b2c24b} (for redis cluster)
  _extractIds(keyList) {
    const ids = (() => {
      const result = []
      for (const key of Array.from(keyList)) {
        const m = key.match(/:\{?([0-9a-f]{24})\}?/) // extract object id
        result.push(m[1])
      }
      return result
    })()
    return ids
  },

  flushAllProjects(options, callback) {
    logger.log({ options }, 'flushing all projects')
    return ProjectFlusher._getKeys(
      docUpdaterKeys.docsInProject({ project_id: '*' }),
      options.limit,
      function (error, project_keys) {
        if (error != null) {
          logger.err({ err: error }, 'error getting keys for flushing')
          return callback(error)
        }
        const project_ids = ProjectFlusher._extractIds(project_keys)
        if (options.dryRun) {
          return callback(null, project_ids)
        }
        const jobs = _.map(project_ids, (project_id) => (cb) =>
          ProjectManager.flushAndDeleteProjectWithLocks(
            project_id,
            { background: true },
            cb
          )
        )
        return async.parallelLimit(
          async.reflectAll(jobs),
          options.concurrency,
          function (error, results) {
            const success = []
            const failure = []
            _.each(results, function (result, i) {
              if (result.error != null) {
                return failure.push(project_ids[i])
              } else {
                return success.push(project_ids[i])
              }
            })
            logger.log({ success, failure }, 'finished flushing all projects')
            return callback(error, { success, failure })
          }
        )
      }
    )
  }
}

module.exports = ProjectFlusher