/*
 * sophia database
 * sphia.org
 *
 * Copyright (c) Dmitry Simonenko
 * BSD License
*/

#include <sp.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>

int sp_fileexists(char *path) {
	struct stat st;
	int rc = lstat(path, &st);
	return rc == 0;
}

int sp_filerm(char *path) {
	return unlink(path);
}

static inline ssize_t
sp_mapsizeof(char *path) {
	struct stat st;
	int rc = lstat(path, &st);
	if (spunlikely(rc == -1))
		return -1;
	return st.st_size;
}

static inline int
sp_mapresize(spfile *f, size_t size) {
	int rc = ftruncate(f->fd, size);
	if (spunlikely(rc == -1))
		return -1;
	f->size = size;
	return 0;
}

static inline int
sp_map(spfile *f, int flags) {
	void *p = mmap(NULL, f->size, flags, MAP_SHARED, f->fd, 0);
	if (p == MAP_FAILED)
		return -1;
	f->map = p;
	return 0;
}

static inline int
sp_unmap(spfile *f) {
	int rc;
	if (f->map) {
		rc = munmap(f->map, f->size);
		f->map = NULL;
		return rc;
	}
	return 0;
}

static inline int
sp_mapopenof(spfile *f, char *path, int flags, uint64_t size)
{
	f->fd = open(path, flags, 0600);
	if (spunlikely(f->fd == -1))
		return -1;
	f->file = sp_strdup(f->a, path);
	if (spunlikely(f->file == NULL)) {
		close(f->fd);
		f->fd = -1;
		return -1;
	}
	f->used = 0;
	f->creat = (flags & O_CREAT ? 1 : 0);
	int rc;
	if (! f->creat) {
		ssize_t sz = sp_mapsizeof(path);
		if (spunlikely(sz == -1))
			goto err;
		f->size = sz;
		rc = sp_map(f, PROT_READ);
		if (spunlikely(rc == -1))
			goto err;
		return 0;
	}
	f->size = 0;
	rc = sp_mapresize(f, size);
	if (spunlikely(rc == -1))
		goto err;
	rc = sp_map(f, PROT_READ|PROT_WRITE);
	if (spunlikely(rc == -1))
		goto err;
	return 0;
err:
	close(f->fd);
	f->fd = -1;
	sp_free(f->a, f->file);
	f->file = NULL;
	return -1;
}

int sp_mapopen(spfile *f, char *path) {
	return sp_mapopenof(f, path, O_RDONLY, 0);
}

int sp_mapnew(spfile *f, char *path, uint64_t size) {
	return sp_mapopenof(f, path, O_RDWR|O_CREAT, size);
}

static inline int
sp_mapsync(spfile *f) {
	return msync(f->map, f->size, MS_SYNC);
}


int sp_mapunlink(spfile *f) {
	return sp_filerm(f->file);
}

static inline int
sp_mapcut(spfile *f)
{
	if (f->creat == 0)
		return 0;
	int rc = sp_mapsync(f);
	if (spunlikely(rc == -1))
		return -1;
	rc = sp_unmap(f);
	if (spunlikely(rc == -1))
		return -1;
	rc = sp_mapresize(f, f->used);
	if (spunlikely(rc == -1))
		return -1;
	return 0;
}

static inline int
sp_fileclose(spfile *f)
{
	/* leave file incomplete */
	if (splikely(f->file)) {
		sp_free(f->a, f->file);
		f->file = NULL;
	}
	int rc;
	if (spunlikely(f->fd != -1)) {
		rc = close(f->fd);
		if (spunlikely(rc == -1))
			return -1;
		f->fd = -1;
	}
	return 0;
}

static inline int
sp_filecomplete(spfile *f)
{
	if (f->creat == 0)
		return 0;
	/* remove .incomplete part */
	f->creat = 0;
	char path[1024];
	snprintf(path, sizeof(path), "%s", f->file);
	char *ext = strrchr(path, '.');
	assert(ext != NULL);
	*ext = 0;
	int rc = rename(f->file, path);
	if (spunlikely(rc == -1))
		return -1;
	char *p = sp_strdup(f->a, path);
	if (spunlikely(p == NULL))
		return -1;
	sp_free(f->a, f->file);
	f->file = p;
	return 0;
}

int sp_mapunmap(spfile *f) {
	return sp_unmap(f);
}

int sp_mapclose(spfile *f)
{
	int rc = sp_mapcut(f);
	if (spunlikely(rc == -1))
		return -1;
	if (f->map) {
		rc = sp_unmap(f);
		if (spunlikely(rc == -1))
			return -1;
	}
	return sp_fileclose(f);
}

int sp_mapcomplete(spfile *f)
{
	if (f->creat == 0)
		return 0;
	/* sync and truncate file by used size */
	int rc = sp_mapcut(f);
	if (spunlikely(rc == -1))
		return -1;
	/* remove .incomplete part */
	rc = sp_filecomplete(f);
	if (spunlikely(rc == -1))
		return -1;
	return sp_map(f, PROT_READ);
}

int sp_mapensure(spfile *f, uint64_t size, float grow)
{
	if (splikely((f->used + size) < f->size))
		return 0;
	int rc = sp_unmap(f);
	if (spunlikely(rc == -1))
		return -1;
	long double nsz = f->size * grow;
	if (spunlikely(nsz < size))
		nsz = size;
	rc = sp_mapresize(f, nsz);
	if (spunlikely(rc == -1))
		return -1;
	return sp_map(f, PROT_READ|PROT_WRITE);
}

static inline int
sp_logopenof(spfile *f, char *path, int flags)
{
	f->creat = 1;
	f->fd = open(path, flags, 0600);
	if (spunlikely(f->fd == -1))
		return -1;
	f->file = sp_strdup(f->a, path);
	if (spunlikely(f->file == NULL)) {
		close(f->fd);
		f->fd = -1;
		return -1;
	}
	f->size = 0;
	f->used = 0;
	return 0;
}

int sp_lognew(spfile *f, char *dir, uint32_t epoch)
{
	char path[1024];
	snprintf(path, sizeof(path), "%s/%"PRIu32".log.incomplete",
	         dir, epoch);
	int rc = sp_logopenof(f, path, O_WRONLY|O_APPEND|O_CREAT);
	if (spunlikely(rc == -1))
		return -1;
	// posix_fadvise(seq)
	return 0;
}

int sp_logcontinue(spfile *f, char *dir, uint32_t epoch) {
	char path[1024];
	snprintf(path, sizeof(path), "%s/%"PRIu32".log.incomplete",
	         dir, epoch);
	int rc = sp_logopenof(f, path, O_WRONLY|O_APPEND);
	if (spunlikely(rc == -1))
		return -1;
	return 0;
}

int sp_logclose(spfile *f) {
	return sp_fileclose(f);
}

static inline int
sp_logsync(spfile *f) {
	return (f->creat ? fsync(f->fd) : 0);
}

int sp_logcomplete(spfile *f)
{
	int rc = sp_logsync(f);
	if (spunlikely(rc == -1))
		return -1;
	return sp_filecomplete(f);
}

int sp_logcompleteforce(spfile *f) {
	int rc = sp_logsync(f);
	if (spunlikely(rc == -1))
		return -1;
	int oldcreat = f->creat;
	f->creat = 1;
	rc = sp_filecomplete(f);
	f->creat = oldcreat;
	return rc;
}

int sp_logunlink(spfile *f) {
	return sp_filerm(f->file);
}

int sp_logflush(spfile *f)
{
	register struct iovec *v = f->iov;
	register uint64_t size = 0;
	register int n = f->iovc;
	do {
		int r;
		do {
			r = writev(f->fd, v, n);
		} while (r == -1 && errno == EINTR);
		if (r < 0) {
			f->iovc = 0;
			return -1;
		}
		size += r;
		while (n > 0) {
			if (v->iov_len > (size_t)r) {
				v->iov_base = (char*)v->iov_base + r;
				v->iov_len -= r;
				break;
			} else {
				r -= v->iov_len;
				v++;
				n--;
			}
		}
	} while (n > 0);
	f->used += size;
	f->iovc = 0;
	return 0;
}

int sp_logrlb(spfile *f)
{
	assert(f->iovc == 0);
	int rc = ftruncate(f->fd, f->svp);
	if (spunlikely(rc == -1))
		return -1;
	f->used = f->svp;
	f->svp = 0;
	return lseek(f->fd, f->used, SEEK_SET);
}

int sp_logeof(spfile *f)
{
	sp_filesvp(f);
	speofh eof = { SPEOF };
	sp_logadd(f, (char*)&eof, sizeof(eof));
	int rc = sp_logflush(f);
	if (spunlikely(rc == -1)) {
		sp_logrlb(f);
		return -1;
	}
	return 0;
}