How would you render this structure of data?

I have coded a smart contract which allows one to store a certain type of structure of datas which can be described as something like that :

├── Client1(Contract)
│   ├── Year2018 (Struct containing string,uint and struct)
│   │   ├── Case 1 (Struct containing string)
│   │   └── Case 2 (Struct containing string)
│   └── Year2017
│       └── Case 1 (Struct containing string)
├── Client 2
│   └── Year2018
│          ├──Case1 (Struct containing string)
│          └──Case2 (You got it)

I managed to fill it correctly and parse it too ( But only one case INDIVIDUALLY). I would like to be able to have a function which returns all the datas in a organized way (such as a multi-dimensionnal array or a JSON for example). What should I use ? Is it possible to store all these value in a bytes array ?

Thanks for your ideas and have a good day !

EDIT:

Should i try something like this ?

function massImport(bytes[] _datas)  view external onlyOwner(){
        for(uint i = 0;i<_datas.length;i++){
            addYear(bytes(_datas[i]));
            for(uint j = 0; j<_datas[i].length;j++){
                addCase(bytes(_datas[i][j]));
            }
        }
    }

I typed the function bytes() because I assume that bytes are the only possible array in this case?

EDIT 2 : Here is the struct 'YEAR'

struct Year{ 
    string entryName; 
    string entryYear; 
    uint permissionType; 
    Elem elem; 
    uint[] elemList; 
    mapping(uint => Elem) allElem; 
    uint elemId; 
}

Do you think that it's too heavy to be stored fully on the blockchain ?