<?php

namespace Modular\ConnectorDependencies\Illuminate\Queue;

class LuaScripts
{
    /**
     * Get the Lua script for computing the size of queue.
     *
     * KEYS[1] - The name of the primary queue
     * KEYS[2] - The name of the "delayed" queue
     * KEYS[3] - The name of the "reserved" queue
     *
     * @return string
     */
    public static function size()
    {
        return <<<'LUA'
        return redis.call('llen', KEYS[1]) + redis.call('zcard', KEYS[2]) + redis.call('zcard', KEYS[3])
        LUA;
    }
    /**
     * Get the Lua script for pushing jobs onto the queue.
     *
     * KEYS[1] - The queue to push the job onto, for example: queues:foo
     * KEYS[2] - The notification list for the queue we are pushing jobs onto, for example: queues:foo:notify
     * ARGV[1] - The job payload
     *
     * @return string
     */
    public static function push()
    {
        return <<<'LUA'
        -- Push the job onto the queue...
        redis.call('rpush', KEYS[1], ARGV[1])
        -- Push a notification onto the "notify" queue...
        redis.call('rpush', KEYS[2], 1)
        LUA;
    }
    /**
     * Get the Lua script for popping the next job off of the queue.
     *
     * KEYS[1] - The queue to pop jobs from, for example: queues:foo
     * KEYS[2] - The queue to place reserved jobs on, for example: queues:foo:reserved
     * KEYS[3] - The notify queue
     * ARGV[1] - The time at which the reserved job will expire
     *
     * @return string
     */
    public static function pop()
    {
        return <<<'LUA'
        -- Pop the first job off of the queue...
        local job = redis.call('lpop', KEYS[1])
        local reserved = false
        
        if(job ~= false) then
            -- Increment the attempt count and place job on the reserved queue...
            reserved = cjson.decode(job)
            reserved['attempts'] = reserved['attempts'] + 1
            reserved = cjson.encode(reserved)
            redis.call('zadd', KEYS[2], ARGV[1], reserved)
            redis.call('lpop', KEYS[3])
        end
        
        return {job, reserved}
        LUA;
    }
    /**
     * Get the Lua script for releasing reserved jobs.
     *
     * KEYS[1] - The "delayed" queue we release jobs onto, for example: queues:foo:delayed
     * KEYS[2] - The queue the jobs are currently on, for example: queues:foo:reserved
     * ARGV[1] - The raw payload of the job to add to the "delayed" queue
     * ARGV[2] - The UNIX timestamp at which the job should become available
     *
     * @return string
     */
    public static function release()
    {
        return <<<'LUA'
        -- Remove the job from the current queue...
        redis.call('zrem', KEYS[2], ARGV[1])
        
        -- Add the job onto the "delayed" queue...
        redis.call('zadd', KEYS[1], ARGV[2], ARGV[1])
        
        return true
        LUA;
    }
    /**
     * Get the Lua script to migrate expired jobs back onto the queue.
     *
     * KEYS[1] - The queue we are removing jobs from, for example: queues:foo:reserved
     * KEYS[2] - The queue we are moving jobs to, for example: queues:foo
     * KEYS[3] - The notification list for the queue we are moving jobs to, for example queues:foo:notify
     * ARGV[1] - The current UNIX timestamp
     *
     * @return string
     */
    public static function migrateExpiredJobs()
    {
        return <<<'LUA'
        -- Get all of the jobs with an expired "score"...
        local val = redis.call('zrangebyscore', KEYS[1], '-inf', ARGV[1])
        
        -- If we have values in the array, we will remove them from the first queue
        -- and add them onto the destination queue in chunks of 100, which moves
        -- all of the appropriate jobs onto the destination queue very safely.
        if(next(val) ~= nil) then
            redis.call('zremrangebyrank', KEYS[1], 0, #val - 1)
        
            for i = 1, #val, 100 do
                redis.call('rpush', KEYS[2], unpack(val, i, math.min(i+99, #val)))
                -- Push a notification for every job that was migrated...
                for j = i, math.min(i+99, #val) do
                    redis.call('rpush', KEYS[3], 1)
                end
            end
        end
        
        return val
        LUA;
    }
    /**
     * Get the Lua script for removing all jobs from the queue.
     *
     * KEYS[1] - The name of the primary queue
     * KEYS[2] - The name of the "delayed" queue
     * KEYS[3] - The name of the "reserved" queue
     * KEYS[4] - The name of the "notify" queue
     *
     * @return string
     */
    public static function clear()
    {
        return <<<'LUA'
        local size = redis.call('llen', KEYS[1]) + redis.call('zcard', KEYS[2]) + redis.call('zcard', KEYS[3])
        redis.call('del', KEYS[1], KEYS[2], KEYS[3], KEYS[4])
        return size
        LUA;
    }
}
