/* SPDX-License-Identifier: MIT */
/*
 * konbuild.h
 *
 * Copyright (c) 2026 KonAki
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#ifndef KONBUILD_H
#define KONBUILD_H

/*** includes ***/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <stdarg.h>
#include <sys/types.h>
#include <sys/stat.h>

#ifdef _WIN32

#ifndef WIN32_LEAN_AND_MEAN
#define WIN32_LEAN_AND_MEAN
#endif
#include <windows.h>
#include <direct.h>

#else

#include <unistd.h>
#include <fcntl.h>
#include <dirent.h>
#include <sys/wait.h>

#endif

/*** definitions ***/

#if defined(__GNUC__) || defined(__clang__)
#define KON_MAYBE_UNUSED __attribute__((unused))
#else
#define KON_MAYBE_UNUSED
#endif

#ifdef _MSC_VER
#define KON_TOOLCHAIN_MSVC 1
#else
#define KON_TOOLCHAIN_MSVC 0
#endif

/* what built this program is what it builds with, unless CC says otherwise. the compiler tells us what it is, but not what it is called on this machine, so
   -DKON_CC='"name"' on the command line that builds it names it by hand, and the program keeps it when it rebuilds itself. gcc and clang (and mingw and llvm-mingw, which
   are those two) are gcc and clang, the rest are cc */
#if defined(KON_CC)
#define KON_CC_DEFAULT KON_CC
#elif defined(__TINYC__)
#define KON_CC_DEFAULT "tcc"
#elif defined(__clang__)
#define KON_CC_DEFAULT "clang"
#elif defined(__GNUC__)
#define KON_CC_DEFAULT "gcc"
#else
#define KON_CC_DEFAULT "cc"
#endif

#if defined(__TINYC__)
#define KON_CC_FAMILY "tcc"
#elif defined(__clang__)
#define KON_CC_FAMILY "clang"
#elif defined(__GNUC__)
#define KON_CC_FAMILY "gcc"
#elif defined(_MSC_VER)
#define KON_CC_FAMILY "msvc"
#else
#define KON_CC_FAMILY "unknown"
#endif

static const char *kon_cc(void) KON_MAYBE_UNUSED;
static const char *kon_ccVersion(void) KON_MAYBE_UNUSED;
static const char *kon_ar(void) KON_MAYBE_UNUSED;

typedef struct kon_cmd {
	char **items;
	size_t count;
	size_t cap;
} KonCmd;

/* a list of paths, the strings belong to the list */
typedef struct kon_list {
	char **items;
	size_t count;
	size_t cap;
} KonList;

void kon_pushCmd_(KonCmd *c, ...);
#define kon_pushCmd(c, ...) kon_pushCmd_((c), __VA_ARGS__, (char *)NULL)
bool kon_runCmdSync(KonCmd *c);
/* the same, with what the command prints appended to a file. NULL is the same as kon_runCmdSync */
bool kon_runCmdLog(KonCmd *c, const char *logPath);

/* a command running on its own, to wait for later. kon_waitAny waits for whichever of procs ends first, gives its number and in ok whether it worked (-1 when none is running).
   kon_cpuCount is how many programs make sense to run at once */
typedef struct kon_proc {
#ifdef _WIN32
	HANDLE handle;
#else
	pid_t pid;
#endif
	int active;
} KonProc;

bool kon_startCmd(KonCmd *c, const char *logPath, KonProc *p);
bool kon_waitProc(KonProc *p);
int kon_waitAny(KonProc *procs, size_t n, bool *ok);
int kon_cpuCount(void);

/* 0 stops the commands being written to stderr as they run, they are by default */
extern int kon_verbose;
void kon_resetCmd(KonCmd *c);
void kon_freeCmd(KonCmd *c);

/* a string that lives until the program ends (or kon_freeTemp), so a command can be filled with built up text without keeping track */
char *kon_fmt(const char *format, ...);
void kon_freeTemp(void);

/* seconds, -1 when the path is not there */
long long kon_mtime(const char *path);
bool kon_needsRebuild(const char *output, const char **sources, size_t nSources);
/* the newest file in a folder (not the folders in it) whose name ends in ext, or -1 */
long long kon_newestIn(const char *dir, const char *ext);

/* a dependency file as -MMD -MF writes it: true when the output is not there, the file is not, or anything it lists is newer than the output or gone */
bool kon_depsNewer(const char *output, const char *depFile);

bool kon_exists(const char *path);
bool kon_isDir(const char *path);
bool kon_mkdir(const char *path);
/* every folder on the way, like mkdir -p */
bool kon_mkdirs(const char *path);
bool kon_remove(const char *path);

/* every file under a folder, in every folder inside it, sorted. the paths are the folder, a slash and the rest */
bool kon_listFiles(const char *dir, KonList *out);
void kon_freeList(KonList *l);

#define KON_REBUILDSELF(argc, argv) kon_rebuildSelf_(__FILE__, (argc), (argv))
void kon_rebuildSelf_(const char *src_path, int argc, char **argv);

#endif /* end of KONBUILD_H */

#ifdef KONBUILD_IMPLEMENTATION

#include <errno.h>

static const char *kon_cc(void) {
#if KON_TOOLCHAIN_MSVC
	return "cl";
#else
	const char *cc = getenv("CC");
	return cc && *cc ? cc : KON_CC_DEFAULT;
#endif
}

/* the version of the compiler this program was built with, as it reports it */
static const char *kon_ccVersion(void) {
#if defined(__clang__)
	return __clang_version__;
#elif defined(__TINYC__)
	return "tcc";
#elif defined(__VERSION__)
	return __VERSION__;
#else
	return "unknown";
#endif
}

static const char *kon_ar(void) {
#if KON_TOOLCHAIN_MSVC
	return "lib";
#else
	const char *ar = getenv("AR");
	return ar ? ar : "ar";
#endif
}

/*** files ***/

long long kon_mtime(const char *path) {
#ifdef _WIN32
	struct _stat64 st;
	if (_stat64(path, &st) != 0) return -1;
#else
	struct stat st;
	if (stat(path, &st) != 0) return -1;
#endif
	return (long long)st.st_mtime;
}

bool kon_exists(const char *path) {
	return kon_mtime(path) >= 0;
}

bool kon_isDir(const char *path) {
	struct stat st;
	if (stat(path, &st) != 0) return false;
	return (st.st_mode & S_IFMT) == S_IFDIR;
}

bool kon_mkdir(const char *path) {
#ifdef _WIN32
	if (_mkdir(path) == 0) return true;
#else
	if (mkdir(path, 0755) == 0) return true;
#endif
	return errno == EEXIST;
}

bool kon_mkdirs(const char *path) {
	size_t n = strlen(path);
	char *copy = (char *)malloc(n + 1);
	size_t i;
	bool ok;

	if (!copy) return false;
	memcpy(copy, path, n + 1);
	for (i = 1; i < n; i++) {
		if (copy[i] != '/' && copy[i] != '\\') continue;
		copy[i] = '\0';
		/* a drive like C: cannot be made, and one that is there already is fine, only the last one has to work */
		kon_mkdir(copy);
		copy[i] = path[i];
	}
	ok = kon_mkdir(copy) || kon_isDir(copy);
	free(copy);
	return ok;
}

bool kon_remove(const char *path) {
	return remove(path) == 0;
}

bool kon_needsRebuild(const char *output, const char **sources, size_t nSources) {
	long long outM = kon_mtime(output);
	size_t i;

	if (outM < 0) return true;
	for (i = 0; i < nSources; i++)
		if (kon_mtime(sources[i]) > outM) return true;

	return false;
}

/*** lists ***/

static bool kon_listPush_(KonList *l, const char *s) {
	size_t n = strlen(s);
	char *copy;

	if (l->count == l->cap) {
		size_t cap = l->cap ? l->cap * 2 : 64;
		char **items = (char **)realloc(l->items, cap * sizeof(char *));

		if (!items) return false;
		l->items = items;
		l->cap = cap;
	}
	copy = (char *)malloc(n + 1);
	if (!copy) return false;
	memcpy(copy, s, n + 1);
	l->items[l->count++] = copy;
	return true;
}

void kon_freeList(KonList *l) {
	size_t i;

	for (i = 0; i < l->count; i++) free(l->items[i]);
	free(l->items);
	*l = (KonList){0};
}

static char *kon_join_(const char *dir, const char *name) {
	size_t a = strlen(dir), b = strlen(name);
	char *s = (char *)malloc(a + b + 2);

	if (!s) return NULL;
	memcpy(s, dir, a);
	if (a > 0 && dir[a - 1] != '/' && dir[a - 1] != '\\') s[a++] = '/';
	memcpy(s + a, name, b + 1);
	return s;
}

/* calls back with every name in a folder, not . and .. . returns false if the folder cannot be read or the callback says stop */
static bool kon_eachName_(const char *dir, bool (*fn)(const char *name, void *user), void *user) {
#ifdef _WIN32
	WIN32_FIND_DATAA fd;
	HANDLE h;
	char *pattern = kon_join_(dir, "*");

	if (!pattern) return false;
	h = FindFirstFileA(pattern, &fd);
	free(pattern);
	if (h == INVALID_HANDLE_VALUE) return false;
	do {
		if (strcmp(fd.cFileName, ".") == 0 || strcmp(fd.cFileName, "..") == 0) continue;
		if (!fn(fd.cFileName, user)) {
			FindClose(h);
			return false;
		}
	} while (FindNextFileA(h, &fd));
	FindClose(h);
	return true;
#else
	DIR *d = opendir(dir);
	struct dirent *e;

	if (!d) return false;
	while ((e = readdir(d)) != NULL) {
		if (strcmp(e->d_name, ".") == 0 || strcmp(e->d_name, "..") == 0) continue;
		if (!fn(e->d_name, user)) {
			closedir(d);
			return false;
		}
	}
	closedir(d);
	return true;
#endif
}

typedef struct kon_newest_ {
	const char *dir, *ext;
	long long newest;
} kon_newest_;

static bool kon_newestName_(const char *name, void *user) {
	kon_newest_ *s = (kon_newest_ *)user;
	size_t n = strlen(name), e = strlen(s->ext);

	if (n >= e && strcmp(name + n - e, s->ext) == 0) {
		char *path = kon_join_(s->dir, name);
		long long m = path ? kon_mtime(path) : -1;

		free(path);
		if (m > s->newest) s->newest = m;
	}
	return true;
}

long long kon_newestIn(const char *dir, const char *ext) {
	kon_newest_ s;

	s.dir = dir;
	s.ext = ext;
	s.newest = -1;
	kon_eachName_(dir, kon_newestName_, &s);
	return s.newest;
}

typedef struct kon_walk_ {
	const char *dir;
	KonList *out;
} kon_walk_;

static bool kon_walkInto_(const char *dir, KonList *out);

static bool kon_walkName_(const char *name, void *user) {
	kon_walk_ *w = (kon_walk_ *)user;
	char *path = kon_join_(w->dir, name);
	bool ok;

	if (!path) return false;
	if (kon_isDir(path)) ok = kon_walkInto_(path, w->out);
	else ok = kon_listPush_(w->out, path);
	free(path);
	return ok;
}

static bool kon_walkInto_(const char *dir, KonList *out) {
	kon_walk_ w;

	w.dir = dir;
	w.out = out;
	return kon_eachName_(dir, kon_walkName_, &w);
}

static int kon_compareNames_(const void *a, const void *b) {
	return strcmp(*(char *const *)a, *(char *const *)b);
}

bool kon_listFiles(const char *dir, KonList *out) {
	*out = (KonList){0};
	if (!kon_walkInto_(dir, out)) {
		kon_freeList(out);
		return false;
	}
	if (out->count > 1) qsort(out->items, out->count, sizeof(char *), kon_compareNames_);
	return true;
}

/*** commands ***/

static void kon_ensureCmd_(KonCmd *c, size_t extra) {
	if (c->count + extra <= c->cap) return;

	c->cap = (c->cap == 0) ? 16 : c->cap * 2;
	while (c->cap < c->count + extra) c->cap *= 2;

	c->items = (char **)realloc(c->items, c->cap * sizeof(char *));
	if (!c->items) {
		fprintf(stderr, "konbuild: out of memory\n");
		exit(1);
	}
}

void kon_pushCmd_(KonCmd *c, ...) {
	va_list ap;
	va_start(ap, c);

	for (;;) {
		char *a = va_arg(ap, char *);
		if (!a) break;

		kon_ensureCmd_(c, 1);
		c->items[c->count++] = a;
	}

	va_end(ap);
}

void kon_resetCmd(KonCmd *c) {
	c->count = 0;
}

void kon_freeCmd(KonCmd *c) {
	free(c->items);
	*c = (KonCmd){0};
}

static char **kon_temp_;
static size_t kon_tempCount_, kon_tempCap_;

char *kon_fmt(const char *format, ...) {
	va_list ap, again;
	int n;
	char *s;

	va_start(ap, format);
	va_copy(again, ap);
	n = vsnprintf(NULL, 0, format, ap);
	va_end(ap);
	if (n < 0) {
		va_end(again);
		fprintf(stderr, "konbuild: bad format\n");
		exit(1);
	}
	s = (char *)malloc((size_t)n + 1);
	if (!s) {
		fprintf(stderr, "konbuild: out of memory\n");
		exit(1);
	}
	vsnprintf(s, (size_t)n + 1, format, again);
	va_end(again);
	if (kon_tempCount_ == kon_tempCap_) {
		kon_tempCap_ = kon_tempCap_ ? kon_tempCap_ * 2 : 64;
		kon_temp_ = (char **)realloc(kon_temp_, kon_tempCap_ * sizeof(char *));
		if (!kon_temp_) {
			fprintf(stderr, "konbuild: out of memory\n");
			exit(1);
		}
	}
	kon_temp_[kon_tempCount_++] = s;
	return s;
}

void kon_freeTemp(void) {
	size_t i;

	for (i = 0; i < kon_tempCount_; i++) free(kon_temp_[i]);
	free(kon_temp_);
	kon_temp_ = NULL;
	kon_tempCount_ = kon_tempCap_ = 0;
}

int kon_verbose = 1;

static void kon_printCmd_(KonCmd *c) {
	size_t i;

	if (!kon_verbose) return;
	for (i = 0; i < c->count; i++) fprintf(stderr, "%s ", c->items[i]);
	fprintf(stderr, "\n");
}

#ifdef _WIN32

/* the quoting that CommandLineToArgvW undoes: a quote is escaped with a backslash, and the backslashes right before it or before the closing quote are doubled */
static size_t kon_quoteArg_(char *out, const char *arg) {
	size_t n = 0;
	const char *p;

	if (*arg && !strpbrk(arg, " \t\n\v\"")) {
		size_t len = strlen(arg);

		if (out) memcpy(out, arg, len);
		return len;
	}
	if (out) out[n] = '"';
	n++;
	for (p = arg;; p++) {
		size_t slashes = 0, i;

		while (*p == '\\') {
			p++;
			slashes++;
		}
		if (*p == '\0') {
			for (i = 0; i < slashes * 2; i++) {
				if (out) out[n] = '\\';
				n++;
			}
			break;
		}
		if (*p == '"') {
			for (i = 0; i < slashes * 2 + 1; i++) {
				if (out) out[n] = '\\';
				n++;
			}
		} else {
			for (i = 0; i < slashes; i++) {
				if (out) out[n] = '\\';
				n++;
			}
		}
		if (out) out[n] = *p;
		n++;
	}
	if (out) out[n] = '"';
	n++;
	return n;
}

bool kon_startCmd(KonCmd *c, const char *logPath, KonProc *p) {
	STARTUPINFOA si;
	PROCESS_INFORMATION pi;
	SECURITY_ATTRIBUTES sa;
	HANDLE log = INVALID_HANDLE_VALUE;
	size_t total = 1, at = 0, i;
	char *line;
	bool ok;

	p->active = 0;
	kon_printCmd_(c);
	if (c->count == 0) return false;

	for (i = 0; i < c->count; i++) total += kon_quoteArg_(NULL, c->items[i]) + 1;
	line = (char *)malloc(total);
	if (!line) return false;
	for (i = 0; i < c->count; i++) {
		at += kon_quoteArg_(line + at, c->items[i]);
		if (i + 1 < c->count) line[at++] = ' ';
	}
	line[at] = '\0';

	memset(&si, 0, sizeof(si));
	memset(&pi, 0, sizeof(pi));
	si.cb = sizeof(si);
	if (logPath) {
		memset(&sa, 0, sizeof(sa));
		sa.nLength = sizeof(sa);
		sa.bInheritHandle = TRUE;
		log = CreateFileA(logPath, FILE_APPEND_DATA, FILE_SHARE_READ | FILE_SHARE_WRITE, &sa, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
		if (log == INVALID_HANDLE_VALUE) {
			fprintf(stderr, "konbuild: cannot open %s (%lu)\n", logPath, (unsigned long)GetLastError());
			free(line);
			return false;
		}
		si.dwFlags = STARTF_USESTDHANDLES;
		si.hStdInput = GetStdHandle(STD_INPUT_HANDLE);
		si.hStdOutput = log;
		si.hStdError = log;
	}

	ok = CreateProcessA(NULL, line, NULL, NULL, TRUE, 0, NULL, NULL, &si, &pi) != 0;
	free(line);
	if (log != INVALID_HANDLE_VALUE) CloseHandle(log);
	if (!ok) {
		fprintf(stderr, "konbuild: could not start %s (%lu)\n", c->items[0], (unsigned long)GetLastError());
		return false;
	}

	CloseHandle(pi.hThread);
	p->handle = pi.hProcess;
	p->active = 1;
	return true;
}

bool kon_waitProc(KonProc *p) {
	DWORD code = 1;

	if (!p->active) return false;
	WaitForSingleObject(p->handle, INFINITE);
	GetExitCodeProcess(p->handle, &code);
	CloseHandle(p->handle);
	p->active = 0;
	return code == 0;
}

int kon_waitAny(KonProc *procs, size_t n, bool *ok) {
	HANDLE handles[MAXIMUM_WAIT_OBJECTS];
	size_t map[MAXIMUM_WAIT_OBJECTS], count = 0, i;
	DWORD r, code = 1;

	for (i = 0; i < n && count < MAXIMUM_WAIT_OBJECTS; i++) {
		if (!procs[i].active) continue;
		handles[count] = procs[i].handle;
		map[count++] = i;
	}
	if (count == 0) return -1;
	r = WaitForMultipleObjects((DWORD)count, handles, FALSE, INFINITE);
	if (r >= WAIT_OBJECT_0 + count) return -1;
	i = map[r - WAIT_OBJECT_0];
	GetExitCodeProcess(procs[i].handle, &code);
	CloseHandle(procs[i].handle);
	procs[i].active = 0;
	*ok = code == 0;
	return (int)i;
}

int kon_cpuCount(void) {
	SYSTEM_INFO si;

	GetSystemInfo(&si);
	return si.dwNumberOfProcessors < 1 ? 1 : (int)si.dwNumberOfProcessors;
}

#else /* posix complian systems */

bool kon_startCmd(KonCmd *c, const char *logPath, KonProc *p) {
	pid_t pid;
	int fd = -1;

	p->active = 0;
	kon_printCmd_(c);
	if (c->count == 0) return false;

	kon_ensureCmd_(c, 1);
	c->items[c->count] = NULL;

	if (logPath) {
		fd = open(logPath, O_WRONLY | O_CREAT | O_APPEND, 0644);
		if (fd < 0) {
			fprintf(stderr, "konbuild: cannot open %s: %s\n", logPath, strerror(errno));
			return false;
		}
	}

	fflush(NULL);
	pid = fork();
	if (pid < 0) {
		fprintf(stderr, "konbuild: fork failed: %s\n", strerror(errno));
		if (fd >= 0) close(fd);
		return false;
	}

	if (pid == 0) {
		if (fd >= 0) {
			dup2(fd, 1);
			dup2(fd, 2);
			close(fd);
		}
		execvp(c->items[0], c->items);
		fprintf(stderr, "konbuild: exec failed: %s: %s\n", c->items[0], strerror(errno));
		_exit(127);
	}

	if (fd >= 0) close(fd);
	p->pid = pid;
	p->active = 1;
	return true;
}

bool kon_waitProc(KonProc *p) {
	int status = 0;

	if (!p->active) return false;
	while (waitpid(p->pid, &status, 0) < 0) {
		if (errno == EINTR) continue;
		fprintf(stderr, "konbuild: waitpid failed: %s\n", strerror(errno));
		p->active = 0;
		return false;
	}
	p->active = 0;
	return WIFEXITED(status) && WEXITSTATUS(status) == 0;
}

int kon_waitAny(KonProc *procs, size_t n, bool *ok) {
	size_t i, active = 0;

	for (i = 0; i < n; i++) {
		if (procs[i].active) active++;
	}
	if (active == 0) return -1;
	for (;;) {
		int status = 0;
		pid_t pid = waitpid(-1, &status, 0);

		if (pid < 0) {
			if (errno == EINTR) continue;
			return -1;
		}
		for (i = 0; i < n; i++) {
			if (procs[i].active && procs[i].pid == pid) {
				procs[i].active = 0;
				*ok = WIFEXITED(status) && WEXITSTATUS(status) == 0;
				return (int)i;
			}
		}
	}
}

int kon_cpuCount(void) {
#ifdef _SC_NPROCESSORS_ONLN
	long n = sysconf(_SC_NPROCESSORS_ONLN);

	return n < 1 ? 1 : (int)n;
#else
	return 1;
#endif
}

#endif

bool kon_runCmdLog(KonCmd *c, const char *logPath) {
	KonProc p;

	if (!kon_startCmd(c, logPath, &p)) return false;
	return kon_waitProc(&p);
}

bool kon_runCmdSync(KonCmd *c) {
	return kon_runCmdLog(c, NULL);
}

/*** dependency files ***/

/* what -MMD writes: "output: source header header \" and the rest on the lines after, a space in a name has a backslash before it */
bool kon_depsNewer(const char *output, const char *depFile) {
	long long outM = kon_mtime(output);
	FILE *f;
	char *buf, *tok;
	long size;
	size_t n, i = 0;
	bool newer = false;

	if (outM < 0) return true;
	f = fopen(depFile, "rb");
	if (!f) return true;
	if (fseek(f, 0, SEEK_END) != 0 || (size = ftell(f)) < 0 || fseek(f, 0, SEEK_SET) != 0) {
		fclose(f);
		return true;
	}
	n = (size_t)size;
	buf = (char *)malloc(n + 1);
	tok = (char *)malloc(n + 1);
	if (!buf || !tok || fread(buf, 1, n, f) != n) {
		fclose(f);
		free(buf);
		free(tok);
		return true;
	}
	fclose(f);
	buf[n] = '\0';

	while (i < n && !newer) {
		size_t len = 0;

		for (;;) {
			if (i < n && (buf[i] == ' ' || buf[i] == '\t' || buf[i] == '\n' || buf[i] == '\r')) i++;
			else if (i + 1 < n && buf[i] == '\\' && buf[i + 1] == '\n') i += 2;
			else if (i + 2 < n && buf[i] == '\\' && buf[i + 1] == '\r' && buf[i + 2] == '\n') i += 3;
			else if (i + 1 == n && buf[i] == '\\') i++;
			else break;
		}
		while (i < n) {
			if (buf[i] == '\\' && i + 1 < n && buf[i + 1] == ' ') {
				tok[len++] = ' ';
				i += 2;
			} else if (buf[i] == '\\' && i + 1 < n && (buf[i + 1] == '\n' || buf[i + 1] == '\r')) {
				break;
			} else if (buf[i] == '\\' && i + 1 == n) {
				break;
			} else if (buf[i] == ' ' || buf[i] == '\t' || buf[i] == '\n' || buf[i] == '\r') {
				break;
			} else {
				tok[len++] = buf[i++];
			}
		}
		tok[len] = '\0';
		if (len == 0 || tok[len - 1] == ':') continue;
		if (kon_mtime(tok) > outM || kon_mtime(tok) < 0) newer = true;
	}
	free(buf);
	free(tok);
	return newer;
}

/*** rebuilding the build program ***/

void kon_rebuildSelf_(const char *src_path, int argc, char **argv) {
#ifndef _WIN32
	(void)argc;
#endif
	const char *self = argv[0];
	const char *hdr_path = __FILE__;
	long long srcM, binM, hdrM, newestM;
	KonCmd cmd = {0};

#ifdef _WIN32
	/* started as just "build", the file is build.exe. the old copy this leaves behind is cleared on the next start */
	if (!kon_exists(self)) self = kon_fmt("%s.exe", self);
	{
		const char *old = kon_fmt("%s.old", self);
		if (kon_exists(old)) kon_remove(old);
	}
#endif

	srcM = kon_mtime(src_path);
	binM = kon_mtime(self);
	if (srcM < 0 || binM < 0) return;

	hdrM = kon_mtime(hdr_path);
	newestM = (hdrM > srcM) ? hdrM : srcM;

	if (newestM <= binM) return;

	fprintf(stderr, "konbuild: %s or %s changed, rebuilding self...\n", src_path, hdr_path);

#ifdef _WIN32
	/* a running program cannot be written over, but it can be renamed */
	{
		const char *old = kon_fmt("%s.old", self);

		if (!MoveFileExA(self, old, MOVEFILE_REPLACE_EXISTING)) {
			fprintf(stderr, "konbuild: could not move %s out of the way (%lu)\n", self, (unsigned long)GetLastError());
			exit(1);
		}
	}
#endif

#if KON_TOOLCHAIN_MSVC
	{
		char *feFlag = kon_fmt("/Fe:%s", self);
		kon_pushCmd(&cmd, (char *)kon_cc(), "/nologo", (char *)src_path, feFlag, NULL);
	}
#else
#ifdef KON_CC
	kon_pushCmd(&cmd, (char *)kon_cc(), kon_fmt("-DKON_CC=\"%s\"", KON_CC), "-o", (char *)self, (char *)src_path, NULL);
#else
	kon_pushCmd(&cmd, (char *)kon_cc(), "-o", (char *)self, (char *)src_path, NULL);
#endif
#endif

	if (!kon_runCmdSync(&cmd)) {
		fprintf(stderr, "konbuild: self-rebuild failed\n");
		exit(1);
	}

	kon_freeCmd(&cmd);

#ifdef _WIN32
	{
		KonCmd relaunch = {0};
		bool ok;
		int i;

		kon_pushCmd(&relaunch, (char *)self, NULL);
		for (i = 1; i < argc; i++) kon_pushCmd(&relaunch, argv[i], NULL);
		ok = kon_runCmdSync(&relaunch);
		kon_freeCmd(&relaunch);
		exit(ok ? 0 : 1);
	}
#else
	execv(self, argv);
	fprintf(stderr, "konbuild: exec self failed: %s\n", strerror(errno));
	exit(1);
#endif
}

#endif /* end of KONBUILD_IMPLEMENTATION */