#include <OS/Modules.h>
#include <OS/Scheduler.h>
#include <OS/Log.h>
#include <VM/Heap.h>
#include <VM/VMM.h>
#include <Lib/String.h>
#include <Arch/CPU.h>
#include "../Common/bootinfo.h"

void ModuleLoad(BootModule* module) {
    OSProcess* userProc = HeapAllocate(sizeof(OSProcess));
    MemorySet(userProc, 0, sizeof(OSProcess));
    userProc->id = SchedulerGetNextProcessID();
    userProc->state = OSTaskStateRunning;
    StringCopy(userProc->name, module->name);

    Address userL0Phys = (Address)PMMAllocatePage();
    Address* userL0Virt = (Address*)VMPhysToHHDM(userL0Phys);
    MemorySet(userL0Virt, 0, kVMPageSize);
    userProc->l0Table = userL0Virt;

    for (BIUInt32 s = 0; s < module->segmentCount; s++) {
        BootModuleSegment* seg = &module->segments[s];

        UInt64 segFlags = kPTENormalMem | kPTEUser;

        if (seg->flags & PF_W) {
            // writable: AP[2]=0 (RW), which is the default
        } else {
            segFlags |= kPTEAccessRO;
        }

        if (seg->flags & PF_X) {
            // executable: default is already executable
        } else {
            segFlags |= kPTEPrivNX | kPTEUserNX;
        }

        for (Size i = 0; i < seg->size; i += kVMPageSize) {
            VMMMapPage((Address*)userL0Phys,
                       seg->physicalBase + i,
                       seg->virtualBase + i,
                       segFlags);
        }

        CPUCleanAndInvalidateCode((void*)VMPhysToHHDM(seg->physicalBase), seg->size);
    }

    Address stackPhys = (Address)PMMAllocatePage();
    Address userStackVirt = 0x80000000;
    UInt64 stackFlags = kPTENormalMem | kPTEUser | kPTEAccessRW | kPTEPrivNX | kPTEUserNX;

    VMMMapPage((Address*)userL0Phys, stackPhys, userStackVirt, stackFlags);

    void (*userEntryPoint)() = (void(*)())module->entry;

    if ((Address)userEntryPoint == 0x0) {
        OSLog("Skipping module %s: entry point is 0x0.\n", module->name);
        return;
    }

    SchedulerSpawn(userEntryPoint, userProc, true, userStackVirt + kVMPageSize);
}