--[[
  Updates the delay set, by picking a delayed job that should
  be processed now.

     Input:
      KEYS[1] 'delayed'
      KEYS[2] 'active'
      KEYS[3] 'wait'
      KEYS[4] 'priority'

      KEYS[5] 'paused'
      KEYS[6] 'meta-paused'

      ARGV[1]  queue.toKey('')
      ARGV[2]  delayed timestamp
      ARGV[3]  queue token

     Events:
      'removed'
]]
local rcall = redis.call;

-- Try to get as much as 1000 jobs at once
local jobs = rcall("ZRANGEBYSCORE", KEYS[1], 0, tonumber(ARGV[2]) * 0x1000, "LIMIT", 0, 1000)

if(#jobs > 0) then
  rcall("ZREM", KEYS[1], unpack(jobs))

  -- check if we need to use push in paused instead of waiting
  local target;
  if rcall("EXISTS", KEYS[6]) ~= 1 then
    target = KEYS[3]
  else
    target = KEYS[5]
  end

  for _, jobId in ipairs(jobs) do
    -- Is this really needed?
    rcall("LREM", KEYS[2], 0, jobId)

    local priority = tonumber(rcall("HGET", ARGV[1] .. jobId, "priority")) or 0
  
    if priority == 0 then
      -- LIFO or FIFO
      rcall("LPUSH", target, jobId)
    else
      -- Priority add
      rcall("ZADD", KEYS[4], priority, jobId)
      local count = rcall("ZCOUNT", KEYS[4], 0, priority)
  
      local len = rcall("LLEN", target)
      local id = rcall("LINDEX", target, len - (count-1))
      if id then
        rcall("LINSERT", target, "BEFORE", id, jobId)
      else
        rcall("RPUSH", target, jobId)
      end
    end
  
    -- Emit waiting event (wait..ing@token)
    rcall("PUBLISH", KEYS[3] .. "ing@" .. ARGV[3], jobId)
    rcall("HSET", ARGV[1] .. jobId, "delay", 0)
  end
end

local nextTimestamp = rcall("ZRANGE", KEYS[1], 0, 0, "WITHSCORES")[2]
if(nextTimestamp ~= nil) then
  rcall("PUBLISH", KEYS[1], nextTimestamp / 0x1000)
end
return nextTimestamp