const std = #import("std");

const stdin: FileDescriptor = 0;
const stdout: FileDescriptor = 1;
const stderr: FileDescriptor = 2;

const Syscall = switch (#import("builtin").cpu) {
    .x86_64 => Syscall_x86_64,
    else => #error("Architecture not supported"),
};

const ProcessId = s32;

const Syscall_x86_64 = enum(usize) {
    read = 0,
    write = 1,
    open = 2,
    close = 3,
    stat = 4,
    fstat = 5,
    lstat = 6,
    poll = 7,
    lseek = 8,
    mmap = 9,
    mprotect = 10,
    munmap = 11,
    brk = 12,
    rt_sigaction = 13,
    rt_sigprocmask = 14,
    rt_sigreturn = 15,
    ioctl = 16,
    pread64 = 17,
    pwrite64 = 18,
    readv = 19,
    writev = 20,
    access = 21,
    pipe = 22,
    select = 23,
    sched_yield = 24,
    mremap = 25,
    msync = 26,
    mincore = 27,
    madvise = 28,
    shmget = 29,
    shmat = 30,
    shmctl = 31,
    dup = 32,
    dup2 = 33,
    pause = 34,
    nanosleep = 35,
    getitimer = 36,
    alarm = 37,
    setitimer = 38,
    getpid = 39,
    sendfile = 40,
    socket = 41,
    connect = 42,
    accept = 43,
    sendto = 44,
    recvfrom = 45,
    sendmsg = 46,
    recvmsg = 47,
    shutdown = 48,
    bind = 49,
    listen = 50,
    getsockname = 51,
    getpeername = 52,
    socketpair = 53,
    setsockopt = 54,
    getsockopt = 55,
    clone = 56,
    fork = 57,
    vfork = 58,
    execve = 59,
    exit = 60,
    wait4 = 61,
    kill = 62,
    uname = 63,
    semget = 64,
    semop = 65,
    semctl = 66,
    shmdt = 67,
    msgget = 68,
    msgsnd = 69,
    msgrcv = 70,
    msgctl = 71,
    fcntl = 72,
    flock = 73,
    fsync = 74,
    fdatasync = 75,
    truncate = 76,
    ftruncate = 77,
    getdents = 78,
    getcwd = 79,
    chdir = 80,
    fchdir = 81,
    rename = 82,
    mkdir = 83,
    rmdir = 84,
    creat = 85,
    link = 86,
    unlink = 87,
    symlink = 88,
    readlink = 89,
    chmod = 90,
    fchmod = 91,
    chown = 92,
    fchown = 93,
    lchown = 94,
    umask = 95,
    gettimeofday = 96,
    getrlimit = 97,
    getrusage = 98,
    sysinfo = 99,
    times = 100,
    ptrace = 101,
    getuid = 102,
    syslog = 103,
    getgid = 104,
    setuid = 105,
    setgid = 106,
    geteuid = 107,
    getegid = 108,
    setpgid = 109,
    getppid = 110,
    getpgrp = 111,
    setsid = 112,
    setreuid = 113,
    setregid = 114,
    getgroups = 115,
    setgroups = 116,
    setresuid = 117,
    getresuid = 118,
    setresgid = 119,
    getresgid = 120,
    getpgid = 121,
    setfsuid = 122,
    setfsgid = 123,
    getsid = 124,
    capget = 125,
    capset = 126,
    rt_sigpending = 127,
    rt_sigtimedwait = 128,
    rt_sigqueueinfo = 129,
    rt_sigsuspend = 130,
    sigaltstack = 131,
    utime = 132,
    mknod = 133,
    uselib = 134,
    personality = 135,
    ustat = 136,
    statfs = 137,
    fstatfs = 138,
    sysfs = 139,
    getpriority = 140,
    setpriority = 141,
    sched_setparam = 142,
    sched_getparam = 143,
    sched_setscheduler = 144,
    sched_getscheduler = 145,
    sched_get_priority_max = 146,
    sched_get_priority_min = 147,
    sched_rr_get_interval = 148,
    mlock = 149,
    munlock = 150,
    mlockall = 151,
    munlockall = 152,
    vhangup = 153,
    modify_ldt = 154,
    pivot_root = 155,
    _sysctl = 156,
    prctl = 157,
    arch_prctl = 158,
    adjtimex = 159,
    setrlimit = 160,
    chroot = 161,
    sync = 162,
    acct = 163,
    settimeofday = 164,
    mount = 165,
    umount2 = 166,
    swapon = 167,
    swapoff = 168,
    reboot = 169,
    sethostname = 170,
    setdomainname = 171,
    iopl = 172,
    ioperm = 173,
    create_module = 174,
    init_module = 175,
    delete_module = 176,
    get_kernel_syms = 177,
    query_module = 178,
    quotactl = 179,
    nfsservctl = 180,
    getpmsg = 181,
    putpmsg = 182,
    afs_syscall = 183,
    tuxcall = 184,
    security = 185,
    gettid = 186,
    readahead = 187,
    setxattr = 188,
    lsetxattr = 189,
    fsetxattr = 190,
    getxattr = 191,
    lgetxattr = 192,
    fgetxattr = 193,
    listxattr = 194,
    llistxattr = 195,
    flistxattr = 196,
    removexattr = 197,
    lremovexattr = 198,
    fremovexattr = 199,
    tkill = 200,
    time = 201,
    futex = 202,
    sched_setaffinity = 203,
    sched_getaffinity = 204,
    set_thread_area = 205,
    io_setup = 206,
    io_destroy = 207,
    io_getevents = 208,
    io_submit = 209,
    io_cancel = 210,
    get_thread_area = 211,
    lookup_dcookie = 212,
    epoll_create = 213,
    epoll_ctl_old = 214,
    epoll_wait_old = 215,
    remap_file_pages = 216,
    getdents64 = 217,
    set_tid_address = 218,
    restart_syscall = 219,
    semtimedop = 220,
    fadvise64 = 221,
    timer_create = 222,
    timer_settime = 223,
    timer_gettime = 224,
    timer_getoverrun = 225,
    timer_delete = 226,
    clock_settime = 227,
    clock_gettime = 228,
    clock_getres = 229,
    clock_nanosleep = 230,
    exit_group = 231,
    epoll_wait = 232,
    epoll_ctl = 233,
    tgkill = 234,
    utimes = 235,
    vserver = 236,
    mbind = 237,
    set_mempolicy = 238,
    get_mempolicy = 239,
    mq_open = 240,
    mq_unlink = 241,
    mq_timedsend = 242,
    mq_timedreceive = 243,
    mq_notify = 244,
    mq_getsetattr = 245,
    kexec_load = 246,
    waitid = 247,
    add_key = 248,
    request_key = 249,
    keyctl = 250,
    ioprio_set = 251,
    ioprio_get = 252,
    inotify_init = 253,
    inotify_add_watch = 254,
    inotify_rm_watch = 255,
    migrate_pages = 256,
    openat = 257,
    mkdirat = 258,
    mknodat = 259,
    fchownat = 260,
    futimesat = 261,
    fstatat64 = 262,
    unlinkat = 263,
    renameat = 264,
    linkat = 265,
    symlinkat = 266,
    readlinkat = 267,
    fchmodat = 268,
    faccessat = 269,
    pselect6 = 270,
    ppoll = 271,
    unshare = 272,
    set_robust_list = 273,
    get_robust_list = 274,
    splice = 275,
    tee = 276,
    sync_file_range = 277,
    vmsplice = 278,
    move_pages = 279,
    utimensat = 280,
    epoll_pwait = 281,
    signalfd = 282,
    timerfd_create = 283,
    eventfd = 284,
    fallocate = 285,
    timerfd_settime = 286,
    timerfd_gettime = 287,
    accept4 = 288,
    signalfd4 = 289,
    eventfd2 = 290,
    epoll_create1 = 291,
    dup3 = 292,
    pipe2 = 293,
    inotify_init1 = 294,
    preadv = 295,
    pwritev = 296,
    rt_tgsigqueueinfo = 297,
    perf_event_open = 298,
    recvmmsg = 299,
    fanotify_init = 300,
    fanotify_mark = 301,
    prlimit64 = 302,
    name_to_handle_at = 303,
    open_by_handle_at = 304,
    clock_adjtime = 305,
    syncfs = 306,
    sendmmsg = 307,
    setns = 308,
    getcpu = 309,
    process_vm_readv = 310,
    process_vm_writev = 311,
    kcmp = 312,
    finit_module = 313,
    sched_setattr = 314,
    sched_getattr = 315,
    renameat2 = 316,
    seccomp = 317,
    getrandom = 318,
    memfd_create = 319,
    kexec_file_load = 320,
    bpf = 321,
    execveat = 322,
    userfaultfd = 323,
    membarrier = 324,
    mlock2 = 325,
    copy_file_range = 326,
    preadv2 = 327,
    pwritev2 = 328,
    pkey_mprotect = 329,
    pkey_alloc = 330,
    pkey_free = 331,
    statx = 332,
    io_pgetevents = 333,
    rseq = 334,
    pidfd_send_signal = 424,
    io_uring_setup = 425,
    io_uring_enter = 426,
    io_uring_register = 427,
    open_tree = 428,
    move_mount = 429,
    fsopen = 430,
    fsconfig = 431,
    fsmount = 432,
    fspick = 433,
    pidfd_open = 434,
    clone3 = 435,
    close_range = 436,
    openat2 = 437,
    pidfd_getfd = 438,
    faccessat2 = 439,
    process_madvise = 440,
    epoll_pwait2 = 441,
    mount_setattr = 442,
    quotactl_fd = 443,
    landlock_create_ruleset = 444,
    landlock_add_rule = 445,
    landlock_restrict_self = 446,
    memfd_secret = 447,
    process_mrelease = 448,
    futex_waitv = 449,
    set_mempolicy_home_node = 450,
    cachestat = 451,
};

const FileDescriptor = s32;

const ProtectionFlags = struct(u32) {
    read: bool,
    write: bool,
    execute: bool,
};

const MapFlags = struct(u32){
    shared: bool,
    private: bool,
    reserved: u2 = 0,
    fixed: bool,
    anonymous: bool,
};

const get_protection_flags = fn(flags: std.os.ProtectionFlags) ProtectionFlags {
    return ProtectionFlags{
        .read = flags.read,
        .write = flags.write,
        .execute = flags.execute,
    };
}

const get_map_flags = fn(flags: std.os.MapFlags) MapFlags{
    return MapFlags{
        .shared = false,
        .private = true,
        .fixed = false,
        .anonymous = true,
    };
}

const mmap = fn(address: ?[&]u8, length: usize, protection_flags: ProtectionFlags, map_flags: MapFlags, fd: s32, offset: u64) usize {
    const flat_protection_flags: u32 = #cast(protection_flags);
    const flat_map_flags: u32 = #cast(map_flags);
    const result = #syscall(#cast(Syscall.mmap), #cast(address), length, flat_protection_flags, flat_map_flags, #cast(fd), offset);
    return result;
}

const munmap = fn(bytes_ptr: [&]const u8, bytes_len: usize) usize {
    const result = #syscall(#cast(Syscall.munmap), #cast(bytes_ptr), bytes_len);
    return result;
}

const readlink = fn(file_path: [&:0]const u8, bytes_ptr: [&]u8, bytes_len: usize) usize {
    const result = #syscall(#cast(Syscall.readlink), #cast(file_path), #cast(bytes_ptr), bytes_len);
    return result;
}

const fork = fn() usize {
    const result = #syscall(#cast(Syscall.fork));
    return result;
}

const execve = fn(path: [&:0]const u8, argv: [&:null]const ?[&:0]const u8, env: [&:null]const ?[&:null]const u8) usize {
    const result = #syscall(#cast(Syscall.execve), #cast(path), #cast(argv), #cast(env));
    return result;
}

const event_file_descriptor = fn(count: u32, flags: u32) usize {
    const result = #syscall(#cast(Syscall.eventfd2), #cast(count), #cast(flags));
    return result;
}

const dup2 = fn(old: s32, new: s32) usize {
    const result = #syscall(#cast(Syscall.dup2), #cast(old), #cast(new));
    return result;
}

const open = fn(path: [&:0]const u8, flags: u32, permissions: u32) usize {
    const result = #syscall(#cast(Syscall.open), #cast(path), flags, permissions);
    return result;
}

const openat = fn(directory_file_descriptor: s32, path: [&:0]const u8, flags: u32, permissions: u32) usize {
    const result = #syscall(#cast(Syscall.openat), #cast(directory_file_descriptor), #cast(path), flags, permissions);
    return result;
}

const read = fn(file_descriptor: s32, bytes_ptr: [&]u8, bytes_len: usize) usize {
    const result = #syscall(#cast(Syscall.read), #cast(file_descriptor), #cast(bytes_ptr), bytes_len);
    return result;
}

const write = fn(file_descriptor: s32, bytes_ptr: [&]const u8, bytes_len: usize) usize {
    const result = #syscall(#cast(Syscall.write), #cast(file_descriptor), #cast(bytes_ptr), bytes_len);
    return result;
}

const close = fn(file_descriptor: s32) usize {
    const result = #syscall(#cast(Syscall.close), #cast(file_descriptor));
    return result;
}

const pipe2 = fn (pipe_pointer: &[2]s32, flags: u32) usize {
    const result = #syscall(#cast(Syscall.pipe2), #cast(pipe_pointer), flags);
    return result;
}

const waitpid = fn(pid: ProcessId, status: &u32, flags: u32, resource_usage: usize) usize {
    const result = #syscall(#cast(Syscall.wait4), pid, #cast(status), flags, resource_usage);
    return result;
}

const poll = fn(file_descriptors: [&]PollFileDescriptor, file_descriptor_count: usize, timeout: s32) usize {
    const result = #syscall(#cast(Syscall.poll), #cast(file_descriptors), file_descriptor_count, #cast(timeout));
    return result;
}

const memfd_create = fn(name: [&:0]const u8, flags: u32) usize {
    const result = #syscall(#cast(Syscall.memfd_create), flags);
    return result;
}

const unwrap_syscall = fn(syscall_result: usize) ?usize {
    const signed_syscall_result: ssize = #cast(syscall_result);
    if (std.os.unwrap_syscall_signed(signed_syscall_result)) {
        return syscall_result;
    } else {
        return null;
    }
}

const EventFileDescriptorFlags = enum(u32) {
    semaphore = 1,
    cloexec = 0o2000000,
    nonblock = 0o4000,
};

const PollFileDescriptor = struct{
    file_descriptor: FileDescriptor,
    events: Poll,
    revents: Poll,

    const Poll = struct(u16) {
        in: bool = false,
        pri: bool = false,
        out: bool = false,
        err: bool = false,
        hup: bool = false,
        nval: bool = false,
        rdnorm: bool = false,
        rdband: bool = false,
    };
};