/* Copyright 2011-2020 Bert Muennich
 * Copyright 2021-2022 nsxiv contributors
 *
 * This file is a part of nsxiv.
 *
 * nsxiv is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published
 * by the Free Software Foundation; either version 2 of the License,
 * or (at your option) any later version.
 *
 * nsxiv is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with nsxiv.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "nsxiv.h"

#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <errno.h>

const char *progname;

void* emalloc(size_t size)
{
	void *ptr;

	ptr = malloc(size);
	if (ptr == NULL)
		error(EXIT_FAILURE, errno, NULL);
	return ptr;
}

void* ecalloc(size_t nmemb, size_t size)
{
	void *ptr;

	ptr = calloc(nmemb, size);
	if (ptr == NULL)
		error(EXIT_FAILURE, errno, NULL);
	return ptr;
}

void* erealloc(void *ptr, size_t size)
{
	ptr = realloc(ptr, size);
	if (ptr == NULL)
		error(EXIT_FAILURE, errno, NULL);
	return ptr;
}

char* estrdup(const char *s)
{
	char *d;
	size_t n = strlen(s) + 1;

	d = malloc(n);
	if (d == NULL)
		error(EXIT_FAILURE, errno, NULL);
	memcpy(d, s, n);
	return d;
}

void error(int eval, int err, const char* fmt, ...)
{
	va_list ap;

	if (eval == 0 && options->quiet)
		return;

	fflush(stdout);
	fprintf(stderr, "%s: ", progname);
	va_start(ap, fmt);
	if (fmt != NULL)
		vfprintf(stderr, fmt, ap);
	va_end(ap);
	if (err != 0)
		fprintf(stderr, "%s%s", fmt != NULL ? ": " : "", strerror(err));
	fputc('\n', stderr);

	if (eval != 0)
		exit(eval);
}

int r_opendir(r_dir_t *rdir, const char *dirname, bool recursive)
{
	if (*dirname == '\0')
		return -1;

	if ((rdir->dir = opendir(dirname)) == NULL) {
		rdir->name = NULL;
		rdir->stack = NULL;
		return -1;
	}

	rdir->stcap = 512;
	rdir->stack = emalloc(rdir->stcap * sizeof(char*));
	rdir->stlen = 0;

	rdir->name = (char*) dirname;
	rdir->d = 0;
	rdir->recursive = recursive;

	return 0;
}

int r_closedir(r_dir_t *rdir)
{
	int ret = 0;

	if (rdir->stack != NULL) {
		while (rdir->stlen > 0)
			free(rdir->stack[--rdir->stlen]);
		free(rdir->stack);
		rdir->stack = NULL;
	}

	if (rdir->dir != NULL) {
		if ((ret = closedir(rdir->dir)) == 0)
			rdir->dir = NULL;
	}

	if (rdir->d != 0) {
		free(rdir->name);
		rdir->name = NULL;
	}

	return ret;
}

char* r_readdir(r_dir_t *rdir, bool skip_dotfiles)
{
	size_t len;
	char *filename;
	struct dirent *dentry;
	struct stat fstats;

	while (true) {
		if (rdir->dir != NULL && (dentry = readdir(rdir->dir)) != NULL) {
			if (dentry->d_name[0] == '.') {
				if (skip_dotfiles)
					continue;
				if (dentry->d_name[1] == '\0')
					continue;
				if (dentry->d_name[1] == '.' && dentry->d_name[2] == '\0')
					continue;
			}

			len = strlen(rdir->name) + strlen(dentry->d_name) + 2;
			filename = emalloc(len);
			snprintf(filename, len, "%s%s%s", rdir->name,
			         rdir->name[strlen(rdir->name)-1] == '/' ? "" : "/",
			         dentry->d_name);

			if (stat(filename, &fstats) < 0)
				continue;
			if (S_ISDIR(fstats.st_mode)) {
				/* put subdirectory on the stack */
				if (rdir->stlen == rdir->stcap) {
					rdir->stcap *= 2;
					rdir->stack = erealloc(rdir->stack,
					                       rdir->stcap * sizeof(char*));
				}
				rdir->stack[rdir->stlen++] = filename;
				continue;
			}
			return filename;
		}

		if (rdir->recursive && rdir->stlen > 0) {
			/* open next subdirectory */
			closedir(rdir->dir);
			if (rdir->d != 0)
				free(rdir->name);
			rdir->name = rdir->stack[--rdir->stlen];
			rdir->d = 1;
			if ((rdir->dir = opendir(rdir->name)) == NULL)
				error(0, errno, "%s", rdir->name);
			continue;
		}
		/* no more entries */
		break;
	}
	return NULL;
}

int r_mkdir(char *path)
{
	char c, *s = path;
	struct stat st;

	while (*s != '\0') {
		if (*s == '/') {
			s++;
			continue;
		}
		for (; *s != '\0' && *s != '/'; s++);
		c = *s;
		*s = '\0';
		if (mkdir(path, 0755) == -1)
			if (errno != EEXIST || stat(path, &st) == -1 || !S_ISDIR(st.st_mode))
				return -1;
		*s = c;
	}
	return 0;
}

void construct_argv(char **argv, unsigned int len, ...)
{
	unsigned int i;
	va_list args;

	va_start(args, len);
	for (i = 0; i < len; ++i)
		argv[i] = va_arg(args, char *);
	va_end(args);
	if (argv[len-1] != NULL)
		error(EXIT_FAILURE, 0, "argv not NULL terminated");
}

spawn_t spawn(const char *cmd, char *const argv[], unsigned int flags)
{
	pid_t pid;
	spawn_t status = { -1, -1, -1 };
	int pfd_read[2] = { -1, -1 };
	int pfd_write[2] = { -1, -1 };
	const bool r = flags & X_READ;
	const bool w = flags & X_WRITE;

	if (cmd == NULL || argv == NULL || flags == 0)
		return status;

	if (r && pipe(pfd_read) < 0) {
		error(0, errno, "pipe: %s", cmd);
		return status;
	}

	if (w && pipe(pfd_write) < 0) {
		if (r) {
			close(pfd_read[0]);
			close(pfd_read[1]);
		}
		error(0, errno, "pipe: %s", cmd);
		return status;
	}

	if ((pid = fork()) == 0) {
		bool err = (r && dup2(pfd_read[1], 1) < 0) || (w && dup2(pfd_write[0], 0) < 0);
		if (r) {
			close(pfd_read[0]);
			close(pfd_read[1]);
		}
		if (w) {
			close(pfd_write[0]);
			close(pfd_write[1]);
		}

		if (err)
			error(EXIT_FAILURE, errno, "dup2: %s", cmd);
		execv(cmd, argv);
		error(EXIT_FAILURE, errno, "exec: %s", cmd);
	}

	if (r)
		close(pfd_read[1]);
	if (w)
		close(pfd_write[0]);

	if (pid < 0) {
		if (r)
			close(pfd_read[0]);
		if (w)
			close(pfd_write[1]);
		error(0, errno, "fork: %s", cmd);
		return status;
	}

	status.pid = pid;
	status.readfd = pfd_read[0];
	status.writefd = pfd_write[1];
	return status;
}