combine multiple arrays so that there are a variety of options - php

Question

So let's say I have this array:
"variants": [
{
"id": 5,
"name": "color",
"item_id": 3,
"created_at": "2018-11-02 15:08:19",
"updated_at": "2018-11-02 15:08:19",
"options": [
{
"id": 13,
"name": "red",
"variant_id": 5,
"created_at": "2018-11-02 15:08:21",
"updated_at": "2018-11-02 15:08:21"
},
{
"id": 14,
"name": "blue",
"variant_id": 5,
"created_at": "2018-11-02 15:08:21",
"updated_at": "2018-11-02 15:08:21"
},
{
"id": 15,
"name": "green",
"variant_id": 5,
"created_at": "2018-11-02 15:08:22",
"updated_at": "2018-11-02 15:08:22"
}
]
},
{
"id": 6,
"name": "size",
"item_id": 3,
"created_at": "2018-11-02 15:08:19",
"updated_at": "2018-11-02 15:08:19",
"options": [
{
"id": 16,
"name": "small",
"variant_id": 6,
"created_at": "2018-11-02 15:08:22",
"updated_at": "2018-11-02 15:08:22"
},
{
"id": 17,
"name": "medium",
"variant_id": 6,
"created_at": "2018-11-02 15:08:22",
"updated_at": "2018-11-02 15:08:22"
},
{
"id": 18,
"name": "large",
"variant_id": 6,
"created_at": "2018-11-02 15:08:22",
"updated_at": "2018-11-02 15:08:22"
}
]
}
]
how would you go about combining all of the possibilities so that i'd have:
red small, red medium, red large, blue small, blue medium, blue large, green small, green medium, green large. Also the arrays would not necessarily always be the same sizes.
This project is being written in PHP specifically using the laravel framework

Answer 1

To accommodate for multiple variants:
function getVariants($obj)
{
$variant = array_shift($obj["variants"]); // we use the variants as a stack
$results = array(); // we will store the results here
foreach($variant["options"] AS $k=>$v) // we iterate the current variants
{
if(count($obj["variants"]) > 0) // if we have more variants still
{
$sub = getVariants($obj); // we call getVariants to build next level
foreach($sub AS $sub_v) // iterate over the results of the child level
{
// concatenate whatever came from children to the current names
$results[] = $v["name"]." ".$sub_v;
}
}
else
{
$results[] = $v["name"]; // this is the last variant so we just add the names.
}
}
return $results;
}
This should work with any depth of combinations needed.
What this code does it use the variants as a stack processing the variant and then if the stack is longer still calling itself to do the same on the next level. Each level returns an array of themselves and their children if any.
https://en.wikipedia.org/wiki/Recursion_(computer_science)