#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <sys/types.h>
#include <dirent.h>

#define LOGFILE "/var/log/pve-hubhotplug.log"

void errExit(const char *err)
{
    fprintf(stderr, "%s\n", err);
    exit(1);
}

char *addDevice(const char *bus, const char *dev, const char *vmid, const char *parentHub, FILE *debug)
{
    DIR *dirfd = opendir("/sys/bus/usb/devices/");

    if (dirfd)
    {
        struct dirent *dirEntry;
        char *devaddr = NULL;
        char *hubMatch = NULL;

        if (parentHub)
        {
            const int len = strlen(parentHub) +1;
            hubMatch = malloc(sizeof(*hubMatch) * len);
            snprintf(hubMatch, len, "%s.", parentHub);
        }
        else
        {
            hubMatch = malloc(sizeof(*hubMatch) * 32);
            snprintf(hubMatch, 31, "%s-", bus);
        }

        while (dirEntry = readdir(dirfd))
        {
            if (strncmp(hubMatch, dirEntry->d_name, strlen(hubMatch)))
                continue;
            char path[1024];
            snprintf(path, 1024, "/sys/bus/usb/devices/%s/devnum", dirEntry->d_name);
            int fic = open(path, O_RDONLY);
            if (fic >= 0)
            {
                char devnum[32];
                int rd = read(fic, devnum, 32);
                close(fic);
                if (rd)
                    devnum[rd -1] = 0;
                if (!strcmp(devnum, dev))
                {
                    fprintf(debug, "Found device %s\n", dirEntry->d_name);
                    devaddr = strdup(dirEntry->d_name +strlen(bus) +1);
                    break;
                }
            }
        }
        closedir(dirfd);
        free(hubMatch);
        if (devaddr)
        {
            char *res = malloc(sizeof(*res) * 1024);
            snprintf(res, 1024, "echo device_add usb-host,bus=xhci.0,hostbus=%s,hostport=%s,id=hubhotplug-%s-%s | qm monitor %s\n", bus, devaddr, bus, dev, vmid);
            free(devaddr);
            return res;
        }
    }
    return NULL;
}

char *delDevice(const char *bus, const char *dev, const char *vmid)
{
    char *res = malloc(sizeof(*res) * 1024);
    snprintf(res, 1024, "echo device_del hubhotplug-%s-%s | qm monitor %s\n", bus, dev, vmid);
    return res;
}

int main(int ac, char **av)
{
    const char *vmid = av[1];
    const char *parentHub = av[1] ? av[2] : NULL;
    const char *devtypeStr = getenv("DEVTYPE");
    const char *actionStr = getenv("ACTION");
    const char *busNumStr = getenv("BUSNUM");
    const char *devNumStr = getenv("DEVNUM");

    if (!vmid)
    {
        fprintf(stderr, "Usage: %s VM-id [parentBus-parentPort]\n", *av);
        exit(1);
    }
    if (!devtypeStr)
        errExit("Missing udev DEVTYPE");
    if (!actionStr)
        errExit("Missing udev ACTION");
    if (!busNumStr)
        errExit("Missing udev BUSNUM");
    if (!devNumStr)
        errExit("Missing udev DEVNUM");

    if (strcmp(devtypeStr, "usb_device"))
        errExit("Ignoring, devtype not matched");

    while (*busNumStr == '0')
        ++busNumStr;
    while (*devNumStr == '0')
        ++devNumStr;

    char *action;
    FILE *f = fopen(LOGFILE, "a");
    if (!strcmp(actionStr, "add"))
        action = addDevice(busNumStr, devNumStr, vmid, parentHub, f);
    else if (!strcmp(actionStr, "remove"))
        action = delDevice(busNumStr, devNumStr, vmid);
    else
        errExit("Invalid ACTION");

    if (action)
    {
        fprintf(f, ">>> %s\n", action);
        system(action);
        free(action);
    }
    fclose(f);
}