#include "elf.h"
#include "service.h"
#include <memory.h>
#include <service.h>
#include <syscalls.h>
#include <util.h>

extern void *kernelCodePageTable;

void *serviceCR3 = 0;
void *serviceESP = 0;
void *mainFunction = NULL;

extern void *functionsStart;
extern void(runFunction)();
extern void(runEnd)();

void run(Service *service, void *main) {
    serviceESP = malloc(0x1000);
    memset(serviceESP, 0, 0x1000);
    serviceESP += 0xFFC;
    *(void **)serviceESP = runEnd;
    sharePage(&service->pagingInfo, serviceESP, serviceESP);
    serviceCR3 = getPhysicalAddressKernel(service->pagingInfo.pageDirectory);
    mainFunction = main;
    runFunction();
}

void resume(Syscall *syscall) {
    mainFunction = syscall->returnAddress;
    serviceESP = syscall->returnEsp;
    serviceCR3 = PTR(syscall->cr3);
    runFunction();
}

void loadElf(void *elfStart, char *serviceName, ListElement **services) {
    // use this function ONLY to load the initrd/loader program(maybe also the
    // ELF loader service)!
    ElfHeader *header = elfStart;
    ProgramHeader *programHeader =
        elfStart + header->programHeaderTablePosition;
    Service *service = malloc(sizeof(Service));
    memset(service, 0, sizeof(Service));
    service->pagingInfo.pageDirectory = malloc(0x1000);
    service->name = serviceName;
    // todo: make this unwritable!
    // todo: use functionsStart as the reference
    sharePage(&(service->pagingInfo), PTR(0xFFC02000),
              PTR(0xFFC02000)); // functionsStart, functionsStart);
    for (uint32_t i = 0; i < header->programHeaderEntryCount; i++) {
        for (uint32_t page = 0; page < programHeader->segmentMemorySize;
             page += 0x1000) {
            void *data = malloc(0x1000);
            memset(data, 0, 0x1000);
            memcpy(elfStart + programHeader->dataOffset, data,
                   MIN(0x1000, programHeader->segmentFileSize - page));
            sharePage(&service->pagingInfo, data,
                      PTR(programHeader->virtualAddress + page));
        }
        programHeader = (void *)programHeader + header->programHeaderEntrySize;
    }
    Provider *main = malloc(sizeof(Provider));
    main->name = "main";
    main->service = service;
    main->address = PTR(header->entryPosition);
    listAdd(services, service);
    listAdd(&service->providers, main);
}