--[[
  Adds a job to the queue by doing the following:
    - Increases the job counter if needed.
    - Creates a new job key with the job data.

    - if delayed:
      - computes timestamp.
      - adds to delayed zset.
      - Emits a global event 'delayed' if the job is delayed.
    - if not delayed
      - Adds the jobId to the wait/paused list in one of three ways:
         - LIFO
         - FIFO
         - prioritized.
      - Adds the job to the "added" list so that workers gets notified.

    Input:
      KEYS[1] 'wait',
      KEYS[2] 'paused'
      KEYS[3] 'meta'
      KEYS[4] 'id'
      KEYS[5] 'delayed'
      KEYS[6] 'priority'
      KEYS[7] events stream key
      KEYS[8] delay stream key

      ARGV[1]  key prefix,
      ARGV[2]  custom id (will not generate one automatically)
      ARGV[3]  name
      ARGV[4]  data (json stringified job data)
      ARGV[5]  opts (json stringified job opts)
      ARGV[6]  timestamp
      ARGV[7]  delay
      ARGV[8]  delayedTimestamp
      ARGV[9]  priority
      ARGV[10] LIFO
      ARGV[11] parentKey?
      ARGV[12] waitChildrenKey key.
      ARGV[13] parent dependencies key.
]]
local jobId
local jobIdKey
local rcall = redis.call

local jobCounter = rcall("INCR", KEYS[4])

if ARGV[2] == "" then
    jobId = jobCounter
    jobIdKey = ARGV[1] .. jobId
else
    jobId = ARGV[2]
    jobIdKey = ARGV[1] .. jobId
    if rcall("EXISTS", jobIdKey) == 1 then
        return jobId .. "" -- convert to string
    end
end

-- Store the job.
rcall("HMSET", jobIdKey, "name", ARGV[3], "data", ARGV[4], "opts", ARGV[5],
      "timestamp", ARGV[6], "delay", ARGV[7], "priority", ARGV[9], "parentKey", ARGV[11])

rcall("XADD", KEYS[7], "*", "event", "added", "jobId", jobId, "name", ARGV[3], "data", ARGV[4], "opts", ARGV[5])

-- Check if job is delayed
local delayedTimestamp = tonumber(ARGV[8])

-- Check if job is a parent, if so add to the parents set
local waitChildrenKey = ARGV[12]
if waitChildrenKey ~= "" then
    rcall("ZADD", waitChildrenKey, ARGV[6], jobId)
    rcall("XADD", KEYS[7], "*", "event", "waiting-children", "jobId", jobId)
elseif (delayedTimestamp ~= 0) then
    local timestamp = delayedTimestamp * 0x1000 + bit.band(jobCounter, 0xfff)
    rcall("ZADD", KEYS[5], timestamp, jobId)
    rcall("XADD", KEYS[7], "*", "event", "delayed", "jobId", jobId, "delay",
          delayedTimestamp)
    rcall("XADD", KEYS[8], "*", "nextTimestamp", delayedTimestamp)
else
    local target

    -- We check for the meta.paused key to decide if we are paused or not
    -- (since an empty list and !EXISTS are not really the same)
    local paused
    if rcall("HEXISTS", KEYS[3], "paused") ~= 1 then
        target = KEYS[1]
        paused = false
    else
        target = KEYS[2]
        paused = true
    end

    -- Standard or priority add
    local priority = tonumber(ARGV[9])
    if priority == 0 then
        -- LIFO or FIFO
        rcall(ARGV[10], target, jobId)
    else
        -- Priority add
        rcall("ZADD", KEYS[6], priority, jobId)
        local count = rcall("ZCOUNT", KEYS[6], 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
    rcall("XADD", KEYS[7], "*", "event", "waiting", "jobId", jobId)
end

-- Check if this job is a child of another job, if so add it to the parents dependencies
-- TODO: Should not be possible to add a child job to a parent that is not in the "waiting-children" status.
-- fail in this case.
local parentDependenciesKey = ARGV[13]
if parentDependenciesKey ~= "" then
    rcall("SADD", parentDependenciesKey, jobIdKey)
end

local maxEvents = rcall("HGET", KEYS[3], "opts.maxLenEvents")
if (maxEvents) then rcall("XTRIM", KEYS[7], "MAXLEN", "~", maxEvents) end

return jobId .. "" -- convert to string