class SidekiqUniqueJobs::UpgradeLocks

def self.call
  redis do |conn|
    new(conn).call
  end
end

def batch_delete(*keys)
  return if keys.empty?
  conn.pipelined do
    if VersionCheck.satisfied?(redis_version, ">= 4.0.0")
      conn.unlink(*keys)
    else
      conn.del(*keys)
    end
  end
end

def batch_scan(match:, count:)
  cursor = "0"
  loop do
    cursor, values = conn.scan(cursor, match: match, count: count)
    yield values
    break if cursor == "0"
  end
end

def call
  with_logging_context do
    return log_info("Already upgraded to #{version}") if conn.hget(upgraded_key, version)
    # TODO: Needs handling of v7.0.0 => v7.0.1 where we don't want to
    return log_info("Skipping upgrade because #{DEAD_VERSION} has been set") if conn.get(DEAD_VERSION)
    log_info("Start - Upgrading Locks")
    upgrade_v6_locks
    delete_unused_v6_keys
    delete_supporting_v6_keys
    conn.hset(upgraded_key, version, now_f)
    log_info("Done - Upgrading Locks")
  end
  @count
end

def delete_suffix(suffix)
  batch_scan(match: "*:#{suffix}", count: BATCH_SIZE) do |keys|
    batch_delete(*keys)
  end
end

def delete_supporting_v6_keys
  batch_delete("unique:keys")
end

def delete_unused_v6_keys
  log_info("Start - Deleting v6 keys")
  OLD_SUFFIXES.each do |suffix|
    delete_suffix(suffix)
  end
  log_info("Done - Deleting v6 keys")
end

def initialize(conn)
  @count         = 0
  @conn          = conn
  redis_version # Avoid pipelined calling redis_version and getting a future.
end

def logging_context
  if logger_context_hash?
    { "uniquejobs" => :upgrade_locks }
  else
    "uniquejobs-upgrade_locks"
  end
end

def now_f
  SidekiqUniqueJobs.now_f
end

def redis_version
  @redis_version ||= SidekiqUniqueJobs.config.redis_version
end

def upgrade_v6_lock(grabbed_key)
  locked_key = grabbed_key.gsub(":GRABBED", ":LOCKED")
  digest     = grabbed_key.gsub(":GRABBED", "")
  locks      = conn.hgetall(grabbed_key)
  conn.pipelined do
    conn.hmset(locked_key, *locks.to_a)
    conn.zadd(DIGESTS, locks.values.first, digest)
  end
end

def upgrade_v6_locks
  log_info("Start - Converting v6 locks to v7")
  conn.scan_each(match: "*:GRABBED", count: BATCH_SIZE) do |grabbed_key|
    upgrade_v6_lock(grabbed_key)
    @count += 1
  end
  log_info("Done - Converting v6 locks to v7")
end

def upgraded_key
  @upgraded_key ||= "#{LIVE_VERSION}:UPGRADED"
end

def version
  SidekiqUniqueJobs.version
end