#include <OS/IPC.h>
#include <OS/Scheduler.h>
#include <Arch/CPU.h>
#include <Arch/Exceptions.h>

UInt64 IPCSend(OSTask* sender, UInt64 handleID, UInt64 data) {
    if (handleID == 0) return -1;
    OSProcess* currentProcess = sender->process;
    OSTask* targetTask = (OSTask*)SchedulerProcessGetHandle(currentProcess, handleID, kOSHandleTypeTask);
    if (!targetTask) return -1;

    if (targetTask->state == OSTaskStateBlockedReceive) {
        ExceptionsContext* receiverContext = (ExceptionsContext*)targetTask->stackPointer;
        receiverContext->x1 = data;
        receiverContext->x0 = currentProcess->id;

        targetTask->state = OSTaskStateRunning;
        return 0;
    }

    if (targetTask->senderWaiting != nullptr) return -2;

    targetTask->senderWaiting = sender;

    SchedulerBlockCurrentTask(OSTaskStateBlockedSend);
    return 0;
}

void IPCReceive(ExceptionsContext* receiverFrame) {
    OSTask* receiver = SchedulerGetCurrentTask();

    if (receiver->senderWaiting != nullptr) {
        OSTask* sender = receiver->senderWaiting;

        ExceptionsContext* senderContext = (ExceptionsContext*)sender->stackPointer;

        receiverFrame->x1 = senderContext->x1;       // Data
        receiverFrame->x0 = sender->process->id;     // Sender ID

        receiver->senderWaiting = nullptr;
        sender->state = OSTaskStateRunning;
        return;
    }

    SchedulerBlockCurrentTask(OSTaskStateBlockedReceive);
}