I would like to ask you for help identifying a rather short story or novel (maybe short series).
I believe I was reading it somewhere on internet and it may have been an amateur author publication or something like that. I do not think it was officially published at that time, but I do not really remember where and under what conditions I was able to read it. It could have been between 2000 - 2005.

I do not remember many details, so some memories may be very sketchy or imprecise. I remember the story was written quite well and it was quite cruel with little to no happy ending, that made it feel different and picked my interest. All the characters end up dead and all fights were lost at the end as far as I can remember. It resembled a real life, where happy ending is not granted despite best efforts and sometimes all goes awry.

**The story is set in maybe no so distant future and it is about asteroid coming to Earth proximity from outer space. Planetary defence forces soon found out it is not just a rock, it is rather a sophisticated base build on asteroid and it is hostile. War soon began.**
I believe this part was following a story of young space fighter pilot involved in fight against this unknown threat. He was lucky enough to hit the enemy fighter the way it got disabled, but not destroyed. People than dragged the enemy fighter to their space base, disassembled and studied it to find out it is unmanned drone, there is no pilot or any living creature. The fighter seemed to be remotely controlled and it got disabled by losing connection to its base.

I think they modified this captured fighter to use it as Trojan horse to get into enemy base. I remember the attempt was successful and one human or maybe a small group landed in enemy dock on asteroid. They surprisingly found empty base with no real crew. It was full of technology, but no living aliens. While heavily armoured from outside, there was no one to stop them once they were inside.
I remember they found a section with terrible stench full of human corpses and body parts. They discovered the "base" is running a bunch of experiments on captured humans trying to understand, how does the human body work. I specifically remember one experiment, where human with cut opened belly got some fluid or something fed through pipe stuck in mouth and it was then leaking out of opened stews lower on his body.
I do not remember this part of story very well and I'm not sure, what happened to this human "intruders". Perhaps they got eventually caught and became experiments themselves.

Not sure, what happened then, but I remember the last part quite well. The war was almost over. Mankind brought to its knees, defence mostly destroyed. We were not able to compete against seemingly unlimited resources and quickly learning mysterious AI.
**Earth became mostly defenceless, so the enemy ships were able to roam around with little to no resistance. They were snatching people and taking them to the asteroid base and no one knew why and what is happening to these people. No one came back to talk about it.** People were able to damage or destroy such a ship from time to time, but compared to production capacities of enemy AI it made no difference.

We could not destroy the enemy from outside, so the last hope was to destroy it from inside. A small group of elite soldiers (of the very few still alive) were chosen (or volunteered?) for a suicide mission. 

**One of the soldiers got a nuclear bomb implanted into his body. I remember he also had a few buttons implanted into his palm reachable by fingers and by a combination of button presses he could control the bomb. The mission was to smuggle the bomb into enemy base close to the AI mainframe and blow it off.**

After he recovered from the surgery the group was just hanging around and waiting for such ship. Not too much later one emerged and tried to capture few people. Soldiers got involved in pretended fight against capturing them and other people in area but only to the point they lost the fight and got captured as planned. All had to look real, so the AI had no clue what is happening. The soldier with bomb in body got electric shock from robot during fight and fall unconsciousness.

They were brought to the asteroid as planned and then they escaped by surprising attack during disembarking. They were then exploring the base trying to find out, where is the main computer running the AI. I do not remember, how it all happened, but they discovered, what are the snatched people being used to. **They were all working in something like mines mining some crystals(?) very important for the AI. They all were under control and working without resistance, like brainless slaves obeying the AI. Soldiers soon found out, how is this accomplished. The human slaves were fed by some blue instance that were nutrition and mind control drug at the same time. Once human tried it, he or she could not resist getting it again. Soldiers soon got to understand, they must avoid it at all cost, otherwise they will loose mind and turn to slaves as well.** But as they were forced to hide among slaves to escape robots searching for them, they pretended being slaves by working. They could not withstand hard work with no water and food for too long and soon one by one tasted the instance and became brainless workers too.

**The soldier with the bomb was more lucky and did not fall victim of the mind controlling substance. He even got so far, that he found the AI core controlling the whole base and all remotely controlled ships, robots and fighters. He tried to activate the bomb only to find out it is not working and he is not able to do anything at all. Plan failed and all hope was lost. The AI engaged him in conversation and disclosed, that it was aware of the plan and the bomb. It also knew the bomb circuitry was damaged when he got paralysed by robot capturing slaves and so that he does not present any real danger to it. AI deliberately let him get that far to have a chance to speak with him.** Maybe the AI even confessed, that it travels the space, subjugates species it finds, and collects all the resources and knowledge it can get.

I'm not sure, if I'm not mistaken by some other story or movie, but I recall very weakly, that the AI core room was described like sphere like room just big enough for an adult man standing and full of backlighted tiles or other lights perhaps changing colour and intensity as AI was speaking or thinking. But I may be completely wrong, unfortunately.

Hopefully someone knows this story. I tried to search for it, but the most specific details I can remember (like the bomb) yielded no results. It may be very difficult as I don't know, if this was released internationally or it was just small story in my native language (Slovak or Czech maybe, not really sure, but my English was not good enough to read a story back then).

Anyway, thanks everyone for trying!