// Copyright 2020 The Libc Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package libc // import "modernc.org/libc"

import (
	"os"
	"strings"
	gotime "time"
	"unicode"
	"unsafe"

	"golang.org/x/sys/unix"
	"modernc.org/libc/errno"
	"modernc.org/libc/fcntl"
	"modernc.org/libc/signal"
	"modernc.org/libc/stdio"
	"modernc.org/libc/sys/types"
	"modernc.org/libc/time"
	"modernc.org/libc/wctype"
)

var (
	startTime = gotime.Now() // For clock(3)
)

// int sigaction(int signum, const struct sigaction *act, struct sigaction *oldact);
func Xsigaction(t *TLS, signum int32, act, oldact uintptr) int32 {
	// 	musl/arch/x86_64/ksigaction.h
	//
	//	struct k_sigaction {
	//		void (*handler)(int);
	//		unsigned long flags;
	//		void (*restorer)(void);
	//		unsigned mask[2];
	//	};
	type k_sigaction struct {
		handler  uintptr
		flags    ulong
		restorer uintptr
		mask     [2]uint32
	}

	var kact, koldact uintptr
	if act != 0 {
		sz := int(unsafe.Sizeof(k_sigaction{}))
		kact = t.Alloc(sz)
		defer t.Free(sz)
		*(*k_sigaction)(unsafe.Pointer(kact)) = k_sigaction{
			handler:  (*signal.Sigaction)(unsafe.Pointer(act)).F__sigaction_handler.Fsa_handler,
			flags:    ulong((*signal.Sigaction)(unsafe.Pointer(act)).Fsa_flags),
			restorer: (*signal.Sigaction)(unsafe.Pointer(act)).Fsa_restorer,
		}
		Xmemcpy(t, kact+unsafe.Offsetof(k_sigaction{}.mask), act+unsafe.Offsetof(signal.Sigaction{}.Fsa_mask), types.Size_t(unsafe.Sizeof(k_sigaction{}.mask)))
	}
	if oldact != 0 {
		panic(todo(""))
	}

	if _, _, err := unix.Syscall6(unix.SYS_RT_SIGACTION, uintptr(signum), kact, koldact, unsafe.Sizeof(k_sigaction{}.mask), 0, 0); err != 0 {
		t.setErrno(err)
		return -1
	}

	if oldact != 0 {
		panic(todo(""))
	}

	return 0
}

// int fcntl(int fd, int cmd, ... /* arg */ );
func Xfcntl64(t *TLS, fd, cmd int32, args uintptr) int32 {
	var arg uintptr
	if args != 0 {
		arg = *(*uintptr)(unsafe.Pointer(args))
	}
	if cmd == fcntl.F_SETFL {
		arg |= unix.O_LARGEFILE
	}
	n, _, err := unix.Syscall(unix.SYS_FCNTL, uintptr(fd), uintptr(cmd), arg)
	if err != 0 {
		// if dmesgs {
		// 	dmesg("%v: fd %v cmd %v", origin(1), fcntlCmdStr(fd), cmd)
		// }
		t.setErrno(err)
		return -1
	}

	// if dmesgs {
	// 	dmesg("%v: %d %s %#x: %d", origin(1), fd, fcntlCmdStr(cmd), arg, n)
	// }
	return int32(n)
}

// int lstat(const char *pathname, struct stat *statbuf);
func Xlstat64(t *TLS, pathname, statbuf uintptr) int32 {
	if _, _, err := unix.Syscall(unix.SYS_LSTAT, pathname, statbuf, 0); err != 0 {
		// if dmesgs {
		// 	dmesg("%v: %q: %v", origin(1), GoString(pathname), err)
		// }
		t.setErrno(err)
		return -1
	}

	// if dmesgs {
	// 	dmesg("%v: %q: ok", origin(1), GoString(pathname))
	// }
	return 0
}

// int stat(const char *pathname, struct stat *statbuf);
func Xstat64(t *TLS, pathname, statbuf uintptr) int32 {
	if _, _, err := unix.Syscall(unix.SYS_STAT, pathname, statbuf, 0); err != 0 {
		// if dmesgs {
		// 	dmesg("%v: %q: %v", origin(1), GoString(pathname), err)
		// }
		t.setErrno(err)
		return -1
	}

	// if dmesgs {
	// 	dmesg("%v: %q: ok", origin(1), GoString(pathname))
	// }
	return 0
}

// int fstat(int fd, struct stat *statbuf);
func Xfstat64(t *TLS, fd int32, statbuf uintptr) int32 {
	if _, _, err := unix.Syscall(unix.SYS_FSTAT, uintptr(fd), statbuf, 0); err != 0 {
		// if dmesgs {
		// 	dmesg("%v: fd %d: %v", origin(1), fd, err)
		// }
		t.setErrno(err)
		return -1
	}

	// if dmesgs {
	// 	dmesg("%v: %d size %#x: ok\n%+v", origin(1), fd, (*stat.Stat)(unsafe.Pointer(statbuf)).Fst_size, (*stat.Stat)(unsafe.Pointer(statbuf)))
	// }
	return 0
}

func Xmmap(t *TLS, addr uintptr, length types.Size_t, prot, flags, fd int32, offset types.Off_t) uintptr {
	return Xmmap64(t, addr, length, prot, flags, fd, offset)
}

// void *mmap(void *addr, size_t length, int prot, int flags, int fd, off_t offset);
func Xmmap64(t *TLS, addr uintptr, length types.Size_t, prot, flags, fd int32, offset types.Off_t) uintptr {
	data, _, err := unix.Syscall6(unix.SYS_MMAP, addr, uintptr(length), uintptr(prot), uintptr(flags), uintptr(fd), uintptr(offset))
	if err != 0 {
		// if dmesgs {
		// 	dmesg("%v: %v", origin(1), err)
		// }
		t.setErrno(err)
		return ^uintptr(0) // (void*)-1
	}

	// if dmesgs {
	// 	dmesg("%v: %#x", origin(1), data)
	// }
	return data
}

// void *mremap(void *old_address, size_t old_size, size_t new_size, int flags, ... /* void *new_address */);
func Xmremap(t *TLS, old_address uintptr, old_size, new_size types.Size_t, flags int32, args uintptr) uintptr {
	var arg uintptr
	if args != 0 {
		arg = *(*uintptr)(unsafe.Pointer(args))
	}
	data, _, err := unix.Syscall6(unix.SYS_MREMAP, old_address, uintptr(old_size), uintptr(new_size), uintptr(flags), arg, 0)
	if err != 0 {
		// if dmesgs {
		// 	dmesg("%v: %v", origin(1), err)
		// }
		t.setErrno(err)
		return ^uintptr(0) // (void*)-1
	}

	// if dmesgs {
	// 	dmesg("%v: %#x", origin(1), data)
	// }
	return data
}

// int ftruncate(int fd, off_t length);
func Xftruncate64(t *TLS, fd int32, length types.Off_t) int32 {
	if _, _, err := unix.Syscall(unix.SYS_FTRUNCATE, uintptr(fd), uintptr(length), 0); err != 0 {
		// if dmesgs {
		// 	dmesg("%v: fd %d: %v", origin(1), fd, err)
		// }
		t.setErrno(err)
		return -1
	}

	// if dmesgs {
	// 	dmesg("%v: %d %#x: ok", origin(1), fd, length)
	// }
	return 0
}

// off64_t lseek64(int fd, off64_t offset, int whence);
func Xlseek64(t *TLS, fd int32, offset types.Off_t, whence int32) types.Off_t {
	n, _, err := unix.Syscall(unix.SYS_LSEEK, uintptr(fd), uintptr(offset), uintptr(whence))
	if err != 0 {
		// if dmesgs {
		// 	dmesg("%v: fd %v, off %#x, whence %v: %v", origin(1), fd, offset, whenceStr(whence), err)
		// }
		t.setErrno(err)
		return -1
	}

	// if dmesgs {
	// 	dmesg("%v: fd %v, off %#x, whence %v: %#x", origin(1), fd, offset, whenceStr(whence), n)
	// }
	return types.Off_t(n)
}

// int utime(const char *filename, const struct utimbuf *times);
func Xutime(t *TLS, filename, times uintptr) int32 {
	if _, _, err := unix.Syscall(unix.SYS_UTIME, filename, times, 0); err != 0 {
		t.setErrno(err)
		return -1
	}

	return 0
}

// unsigned int alarm(unsigned int seconds);
func Xalarm(t *TLS, seconds uint32) uint32 {
	n, _, err := unix.Syscall(unix.SYS_ALARM, uintptr(seconds), 0, 0)
	if err != 0 {
		panic(todo(""))
	}

	return uint32(n)
}

// time_t time(time_t *tloc);
func Xtime(t *TLS, tloc uintptr) types.Time_t {
	n, _, err := unix.Syscall(unix.SYS_TIME, tloc, 0, 0)
	if err != 0 {
		t.setErrno(err)
		return types.Time_t(-1)
	}

	if tloc != 0 {
		*(*types.Time_t)(unsafe.Pointer(tloc)) = types.Time_t(n)
	}
	return types.Time_t(n)
}

// int getrlimit(int resource, struct rlimit *rlim);
func Xgetrlimit64(t *TLS, resource int32, rlim uintptr) int32 {
	if _, _, err := unix.Syscall(unix.SYS_GETRLIMIT, uintptr(resource), uintptr(rlim), 0); err != 0 {
		t.setErrno(err)
		return -1
	}

	return 0
}

// int mkdir(const char *path, mode_t mode);
func Xmkdir(t *TLS, path uintptr, mode types.Mode_t) int32 {
	if _, _, err := unix.Syscall(unix.SYS_MKDIR, path, uintptr(mode), 0); err != 0 {
		t.setErrno(err)
		return -1
	}

	// if dmesgs {
	// 	dmesg("%v: %q: ok", origin(1), GoString(path))
	// }
	return 0
}

// int symlink(const char *target, const char *linkpath);
func Xsymlink(t *TLS, target, linkpath uintptr) int32 {
	if _, _, err := unix.Syscall(unix.SYS_SYMLINK, target, linkpath, 0); err != 0 {
		t.setErrno(err)
		return -1
	}

	// if dmesgs {
	// 	dmesg("%v: %q %q: ok", origin(1), GoString(target), GoString(linkpath))
	// }
	return 0
}

// int chmod(const char *pathname, mode_t mode)
func Xchmod(t *TLS, pathname uintptr, mode types.Mode_t) int32 {
	if _, _, err := unix.Syscall(unix.SYS_CHMOD, pathname, uintptr(mode), 0); err != 0 {
		t.setErrno(err)
		return -1
	}

	// if dmesgs {
	// 	dmesg("%v: %q %#o: ok", origin(1), GoString(pathname), mode)
	// }
	return 0
}

// int utimes(const char *filename, const struct timeval times[2]);
func Xutimes(t *TLS, filename, times uintptr) int32 {
	if _, _, err := unix.Syscall(unix.SYS_UTIMES, filename, times, 0); err != 0 {
		t.setErrno(err)
		return -1
	}

	// if dmesgs {
	// 	dmesg("%v: %q: ok", origin(1), GoString(filename))
	// }
	return 0
}

// int unlink(const char *pathname);
func Xunlink(t *TLS, pathname uintptr) int32 {
	if _, _, err := unix.Syscall(unix.SYS_UNLINK, pathname, 0, 0); err != 0 {
		t.setErrno(err)
		return -1
	}

	// if dmesgs {
	// 	dmesg("%v: %q: ok", origin(1), GoString(pathname))
	// }
	return 0
}

// int access(const char *pathname, int mode);
func Xaccess(t *TLS, pathname uintptr, mode int32) int32 {
	if _, _, err := unix.Syscall(unix.SYS_ACCESS, pathname, uintptr(mode), 0); err != 0 {
		// if dmesgs {
		// 	dmesg("%v: %q: %v", origin(1), GoString(pathname), err)
		// }
		t.setErrno(err)
		return -1
	}

	// if dmesgs {
	// 	dmesg("%v: %q %#o: ok", origin(1), GoString(pathname), mode)
	// }
	return 0
}

// int rmdir(const char *pathname);
func Xrmdir(t *TLS, pathname uintptr) int32 {
	if _, _, err := unix.Syscall(unix.SYS_RMDIR, pathname, 0, 0); err != 0 {
		t.setErrno(err)
		return -1
	}

	// if dmesgs {
	// 	dmesg("%v: %q: ok", origin(1), GoString(pathname))
	// }
	return 0
}

// int rename(const char *oldpath, const char *newpath);
func Xrename(t *TLS, oldpath, newpath uintptr) int32 {
	if _, _, err := unix.Syscall(unix.SYS_RENAME, oldpath, newpath, 0); err != 0 {
		t.setErrno(err)
		return -1
	}

	return 0
}

// int mknod(const char *pathname, mode_t mode, dev_t dev);
func Xmknod(t *TLS, pathname uintptr, mode types.Mode_t, dev types.Dev_t) int32 {
	if _, _, err := unix.Syscall(unix.SYS_MKNOD, pathname, uintptr(mode), uintptr(dev)); err != 0 {
		t.setErrno(err)
		return -1
	}

	return 0
}

// int chown(const char *pathname, uid_t owner, gid_t group);
func Xchown(t *TLS, pathname uintptr, owner types.Uid_t, group types.Gid_t) int32 {
	if _, _, err := unix.Syscall(unix.SYS_CHOWN, pathname, uintptr(owner), uintptr(group)); err != 0 {
		t.setErrno(err)
		return -1
	}

	return 0
}

// int link(const char *oldpath, const char *newpath);
func Xlink(t *TLS, oldpath, newpath uintptr) int32 {
	if _, _, err := unix.Syscall(unix.SYS_LINK, oldpath, newpath, 0); err != 0 {
		t.setErrno(err)
		return -1
	}

	return 0
}

// int pipe(int pipefd[2]);
func Xpipe(t *TLS, pipefd uintptr) int32 {
	if _, _, err := unix.Syscall(unix.SYS_PIPE, pipefd, 0, 0); err != 0 {
		t.setErrno(err)
		return -1
	}

	return 0
}

// int dup2(int oldfd, int newfd);
func Xdup2(t *TLS, oldfd, newfd int32) int32 {
	n, _, err := unix.Syscall(unix.SYS_DUP2, uintptr(oldfd), uintptr(newfd), 0)
	if err != 0 {
		t.setErrno(err)
		return -1
	}

	return int32(n)
}

// ssize_t readlink(const char *restrict path, char *restrict buf, size_t bufsize);
func Xreadlink(t *TLS, path, buf uintptr, bufsize types.Size_t) types.Ssize_t {
	n, _, err := unix.Syscall(unix.SYS_READLINK, path, buf, uintptr(bufsize))
	if err != 0 {
		t.setErrno(err)
		return -1
	}

	return types.Ssize_t(n)
}

// FILE *fopen64(const char *pathname, const char *mode);
func Xfopen64(t *TLS, pathname, mode uintptr) uintptr {
	m := strings.ReplaceAll(GoString(mode), "b", "")
	var flags int
	switch m {
	case "r":
		flags = os.O_RDONLY
	case "r+":
		flags = os.O_RDWR
	case "w":
		flags = os.O_WRONLY | os.O_CREATE | os.O_TRUNC
	case "w+":
		flags = os.O_RDWR | os.O_CREATE | os.O_TRUNC
	case "a":
		flags = os.O_WRONLY | os.O_CREATE | os.O_APPEND
	case "a+":
		flags = os.O_RDWR | os.O_CREATE | os.O_APPEND
	default:
		panic(m)
	}
	//TODO- flags |= fcntl.O_LARGEFILE
	fd, _, err := unix.Syscall(unix.SYS_OPEN, pathname, uintptr(flags|unix.O_LARGEFILE), 0666)
	if err != 0 {
		t.setErrno(err)
		return 0
	}

	if p := newFile(t, int32(fd)); p != 0 {
		return p
	}

	Xclose(t, int32(fd))
	t.setErrno(errno.ENOMEM)
	return 0
}

// int iswspace(wint_t wc);
func Xiswspace(t *TLS, wc wctype.Wint_t) int32 {
	return Bool32(unicode.IsSpace(rune(wc)))
}

// int iswalnum(wint_t wc);
func Xiswalnum(t *TLS, wc wctype.Wint_t) int32 {
	return Bool32(unicode.IsLetter(rune(wc)) || unicode.IsNumber(rune(wc)))
}

// int setrlimit(int resource, const struct rlimit *rlim);
func Xsetrlimit64(t *TLS, resource int32, rlim uintptr) int32 {
	if _, _, err := unix.Syscall(unix.SYS_SETRLIMIT, uintptr(resource), uintptr(rlim), 0); err != 0 {
		t.setErrno(err)
		return -1
	}

	return 0
}

func AtomicLoadPInt8(addr uintptr) (val int8) {
	return int8(a_load_8(addr))
}

func AtomicLoadPInt16(addr uintptr) (val int16) {
	return int16(a_load_16(addr))
}

func AtomicLoadPUint8(addr uintptr) byte {
	return byte(a_load_8(addr))
}

func AtomicLoadPUint16(addr uintptr) uint16 {
	return uint16(a_load_16(addr))
}

func AtomicLoadNUint8(ptr uintptr, memorder int32) uint8 {
	return byte(a_load_8(ptr))
}

var _table1 = [384]int32{
	129: int32(1),
	130: int32(2),
	131: int32(3),
	132: int32(4),
	133: int32(5),
	134: int32(6),
	135: int32(7),
	136: int32(8),
	137: int32(9),
	138: int32(10),
	139: int32(11),
	140: int32(12),
	141: int32(13),
	142: int32(14),
	143: int32(15),
	144: int32(16),
	145: int32(17),
	146: int32(18),
	147: int32(19),
	148: int32(20),
	149: int32(21),
	150: int32(22),
	151: int32(23),
	152: int32(24),
	153: int32(25),
	154: int32(26),
	155: int32(27),
	156: int32(28),
	157: int32(29),
	158: int32(30),
	159: int32(31),
	160: int32(32),
	161: int32(33),
	162: int32(34),
	163: int32(35),
	164: int32(36),
	165: int32(37),
	166: int32(38),
	167: int32(39),
	168: int32(40),
	169: int32(41),
	170: int32(42),
	171: int32(43),
	172: int32(44),
	173: int32(45),
	174: int32(46),
	175: int32(47),
	176: int32(48),
	177: int32(49),
	178: int32(50),
	179: int32(51),
	180: int32(52),
	181: int32(53),
	182: int32(54),
	183: int32(55),
	184: int32(56),
	185: int32(57),
	186: int32(58),
	187: int32(59),
	188: int32(60),
	189: int32(61),
	190: int32(62),
	191: int32(63),
	192: int32(64),
	193: int32('a'),
	194: int32('b'),
	195: int32('c'),
	196: int32('d'),
	197: int32('e'),
	198: int32('f'),
	199: int32('g'),
	200: int32('h'),
	201: int32('i'),
	202: int32('j'),
	203: int32('k'),
	204: int32('l'),
	205: int32('m'),
	206: int32('n'),
	207: int32('o'),
	208: int32('p'),
	209: int32('q'),
	210: int32('r'),
	211: int32('s'),
	212: int32('t'),
	213: int32('u'),
	214: int32('v'),
	215: int32('w'),
	216: int32('x'),
	217: int32('y'),
	218: int32('z'),
	219: int32(91),
	220: int32(92),
	221: int32(93),
	222: int32(94),
	223: int32(95),
	224: int32(96),
	225: int32('a'),
	226: int32('b'),
	227: int32('c'),
	228: int32('d'),
	229: int32('e'),
	230: int32('f'),
	231: int32('g'),
	232: int32('h'),
	233: int32('i'),
	234: int32('j'),
	235: int32('k'),
	236: int32('l'),
	237: int32('m'),
	238: int32('n'),
	239: int32('o'),
	240: int32('p'),
	241: int32('q'),
	242: int32('r'),
	243: int32('s'),
	244: int32('t'),
	245: int32('u'),
	246: int32('v'),
	247: int32('w'),
	248: int32('x'),
	249: int32('y'),
	250: int32('z'),
	251: int32(123),
	252: int32(124),
	253: int32(125),
	254: int32(126),
	255: int32(127),
}

var _ptable1 = uintptr(unsafe.Pointer(&_table1)) + uintptr(128)*4

func X__ctype_tolower_loc(tls *TLS) (r uintptr) {
	return uintptr(unsafe.Pointer(&_ptable1))
}

type Tin6_addr = struct {
	F__in6_union struct {
		F__s6_addr16 [0][8]uint16
		F__s6_addr32 [0][4]uint32
		F__s6_addr   [16]uint8
	}
}

var Xin6addr_any = Tin6_addr{}

func Xrewinddir(tls *TLS, f uintptr) {
	Xfseek(tls, f, 0, stdio.SEEK_SET)
}

// clock_t clock(void);
func Xclock(t *TLS) time.Clock_t {
	return time.Clock_t(gotime.Since(startTime) * gotime.Duration(time.CLOCKS_PER_SEC) / gotime.Second)
}