/* Target-only port suspend/resume. Never seizes an owner, detaches a driver, or resets a hub. */
#include <CoreFoundation/CoreFoundation.h>
#include <IOKit/IOCFPlugIn.h>
#include <IOKit/IOKitLib.h>
#include <IOKit/usb/IOUSBLib.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#define REQUIRE(c) do { if (!(c)) { fprintf(stderr, "Failed at line %d: %s\n", __LINE__, #c); exit(1); } } while (0)
static IOUSBDeviceInterface500 **device;
static bool opened, suspended;

static void cleanup(void) {
    if (suspended) {
        IOReturn result = (*device)->USBDeviceSuspend(device, false);
        fprintf(stderr, "Cleanup resume: 0x%08x\n", (unsigned int)result);
    }
    if (opened) (*device)->USBDeviceClose(device);
    if (device) (*device)->Release(device);
}

static UInt32 information(const char *stage) {
    UInt32 value = 0;
    IOReturn result = (*device)->GetUSBDeviceInformation(device, &value);
    printf("{\"stage\":\"%s\",\"result\":\"0x%08x\",\"information\":%u,\"suspended\":%s}\n",
        stage, (unsigned int)result, value, (value & kUSBInformationDeviceIsSuspendedMask) ? "true" : "false");
    fflush(stdout);
    REQUIRE(result == kIOReturnSuccess);
    return value;
}

int main(int count, char **arguments) {
    REQUIRE(count == 2 && strlen(arguments[1]) == 16);
    CFStringRef expected = CFStringCreateWithCString(NULL, arguments[1], kCFStringEncodingUTF8);
    REQUIRE(expected != NULL);
    io_iterator_t iterator;
    REQUIRE(IOServiceGetMatchingServices(kIOMainPortDefault, IOServiceMatching("IOUSBHostDevice"), &iterator) == KERN_SUCCESS);
    io_service_t selected = IO_OBJECT_NULL, service;
    unsigned matches = 0;
    while ((service = IOIteratorNext(iterator))) {
        CFTypeRef serial = IORegistryEntryCreateCFProperty(service, CFSTR("USB Serial Number"), NULL, 0);
        CFTypeRef vid = IORegistryEntryCreateCFProperty(service, CFSTR("idVendor"), NULL, 0);
        CFTypeRef pid = IORegistryEntryCreateCFProperty(service, CFSTR("idProduct"), NULL, 0);
        int vendor = 0, product = 0;
        if (vid && CFGetTypeID(vid) == CFNumberGetTypeID()) CFNumberGetValue(vid, kCFNumberIntType, &vendor);
        if (pid && CFGetTypeID(pid) == CFNumberGetTypeID()) CFNumberGetValue(pid, kCFNumberIntType, &product);
        bool match = serial && CFGetTypeID(serial) == CFStringGetTypeID() && CFEqual(serial, expected) && vendor == 0xcafe && product == 0x4014;
        if (serial) CFRelease(serial);
        if (vid) CFRelease(vid);
        if (pid) CFRelease(pid);
        if (match) { ++matches; if (!selected) selected = service; else IOObjectRelease(service); }
        else IOObjectRelease(service);
    }
    IOObjectRelease(iterator);
    CFRelease(expected);
    REQUIRE(matches == 1);
    IOCFPlugInInterface **plugin = NULL;
    SInt32 score = 0;
    REQUIRE(IOCreatePlugInInterfaceForService(selected, kIOUSBDeviceUserClientTypeID, kIOCFPlugInInterfaceID, &plugin, &score) == kIOReturnSuccess);
    IOObjectRelease(selected);
    REQUIRE((*plugin)->QueryInterface(plugin, CFUUIDGetUUIDBytes(kIOUSBDeviceInterfaceID500), (LPVOID *)&device) == S_OK);
    (*plugin)->Release(plugin);
    REQUIRE(atexit(cleanup) == 0);
    UInt16 vendor = 0, product = 0;
    REQUIRE((*device)->GetDeviceVendor(device, &vendor) == kIOReturnSuccess && vendor == 0xcafe);
    REQUIRE((*device)->GetDeviceProduct(device, &product) == kIOReturnSuccess && product == 0x4014);
    REQUIRE(!(information("before_open") & kUSBInformationDeviceIsSuspendedMask));
    IOReturn result = (*device)->USBDeviceOpen(device);
    printf("{\"stage\":\"open_without_seize\",\"result\":\"0x%08x\"}\n", (unsigned int)result);
    fflush(stdout);
    REQUIRE(result == kIOReturnSuccess);
    opened = true;
    result = (*device)->USBDeviceSuspend(device, true);
    printf("{\"stage\":\"suspend\",\"result\":\"0x%08x\"}\n", (unsigned int)result);
    REQUIRE(result == kIOReturnSuccess);
    suspended = true;
    struct timespec pause = {.tv_sec = 1};
    nanosleep(&pause, NULL);
    REQUIRE(information("after_suspend") & kUSBInformationDeviceIsSuspendedMask);
    result = (*device)->USBDeviceSuspend(device, false);
    printf("{\"stage\":\"resume\",\"result\":\"0x%08x\"}\n", (unsigned int)result);
    REQUIRE(result == kIOReturnSuccess);
    suspended = false;
    REQUIRE(!(information("after_resume") & kUSBInformationDeviceIsSuspendedMask));
    return 0;
}