PArray :: struct (Data_Type : Type, Handle_Type : Type) {
    data: [..] Data_Type;
    indices: [..] u32;
}

parray_reset :: (using array: *PArray) {
    array_reset(*array.data);
    array_reset(*array.indices);
}

parray_free :: (using array: PArray) {
    array_free(array.data);
    array_free(array.indices);
}

parray_reserve :: (using parray: *PArray, capacity: s32) {
    if capacity > 0 {
       array_reserve(*data, capacity);
       array_reserve(*indices, capacity);
    }
}

parray_get :: (using parray: PArray, handle: parray.Handle_Type) -> *parray.Data_Type {
    index := indices[handle - 1] - 1;
    return *data[index];
}

parray_get_val :: (using parray: PArray, handle: parray.Handle_Type) -> parray.Data_Type {
    assert(xx handle > 0 && xx handle <= indices.count);
    index := indices[handle - 1] - 1;
    return data[index];
}

parray_add :: (using parray: *PArray, value: parray.Data_Type) -> parray.Handle_Type {
    array_add(*data, value);
    index := cast(u32)data.count;

    handle : Handle_Type = 0;

    // find the next empty index
    for *val, i: indices {
        if <<val == 0 {
            <<val = index;
            handle = cast(Handle_Type)i + 1;
            break;
        }
    }

    if handle == 0 {
        array_add(*indices, index);
        handle = cast(Handle_Type)indices.count;
    }

    return handle;
}

parray_remove :: (using parray: *PArray, handle: parray.Handle_Type) {
    index := indices[handle - 1] - 1;
    indices[handle - 1] = 0;

    if data.count == 1 {
        data.count = 0;
        return;
    }

    data[index] = data[data.count-1];

    for * indices {
        if <<it == data.count {
            <<it = index + 1;
            break;
        }
    }

    data.count -= 1;
}

for_expansion :: (parray: *PArray, body: Code, flags: For_Flags) #expand {
    for *value, `it_index: parray.data {  
        #if flags & .POINTER {
            `it := value;
        } else {
            `it := <<value;
        }
        #insert body;
    }
}