Latest Eclipse on Ubuntu Arduino esp32

[borgdrone7]

Hi,

I managed to setup ESP32 IDF on Eclipse in Ubuntu following tutorials however I decided that I want to go Arduino ESP32 route however I am not able to get Eclipse on Ubuntu working with it.
When I try to add JSON for esp32 (https://dl.espressif.com/dl/package_esp32_index.json) I get error "could not find package ..." although the same link opens in my browser without issues and downloads in Arduino IDE.
Also regardless of the JSON, since I installed ESP IDF plugin, when creating new target I have option of selecting ESP32, however when I add it, it is not shown in targets list so I cannot select it.

I have very big code base for esp8266 and I want simply to rewrite it (and reuse as much as possible) on esp32. I don't need and want multi core or FreeRTOS as the code already handles that stuff using timers and we want to keep the code as near as possible to original one. In essence I just want Arduino ESP32 libs to run on esp32 single core and be able to use it's sensors, wifi and pins.

Anyone knows how can I get it to compile on Eclipse/Ubuntu?

Thanks in advance