/*
 * Copyright (C) 2009 Andre Noll <maan@tuebingen.mpg.de>
 *
 * Licensed under the GPL v2. For licencing details see COPYING.
 */

/**
 * \file osltar.c A simple file archiver with many limitations. Do not use it.
 * It is just an * example to illustrate programming with libosl.
 */

#include <inttypes.h>
#include <osl.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <sys/types.h>
#include <dirent.h>
#include <errno.h>
#include <sys/mman.h>
#include <fcntl.h>

/** The columns of the osl table. */
enum osltar_columns {
	/** File name. */
	OTC_NAME,
	/** File content. */
	OTC_DATA,
	/** two. */
	NUM_OT_COLUMNS
};


/**
 * Compare two osl objects of string type.
 *
 * \param obj1 Pointer to the first object.
 * \param obj2 Pointer to the second object.
 *
 * \return It returns an integer less than, equal to, or greater than zero if
 * \a obj1 is found, respectively, to be less than, to match, or be greater than
 * obj2.
 *
 * \sa strcmp(3), strncmp(3), osl_compare_func.
 */
static int string_compare(const struct osl_object *obj1, const struct osl_object *obj2)
{
	const char *str1 = (const char *)obj1->data;
	const char *str2 = (const char *)obj2->data;
	return strcmp(str1, str2);
}

static struct osl_column_description tar_table_cols[] = {
	[OTC_NAME] = {
		.storage_type = OSL_MAPPED_STORAGE,
		.storage_flags = OSL_RBTREE | OSL_UNIQUE,
		.name = "filename",
		.compare_function = string_compare,
	},
	[OTC_DATA] = {
		.storage_type = OSL_MAPPED_STORAGE,
		.storage_flags = 0,
		.name = "data",
	},
};

static struct osl_table *table;

static struct osl_table_description tar_table_desc = {
	.name = "tar_table",
	.num_columns = NUM_OT_COLUMNS,
	.flags = 0,
	.column_descriptions = tar_table_cols,
};

static void print_usage_and_die(void)
{
	fprintf(stderr, "usage:\n\tosltar c <db_dir> <data_dir>\n");
	fprintf(stderr, "\tosltar x <db_dir> file1 [file2...]\n");
	fprintf(stderr, "\tosltar t <db_dir>\n");
	exit(EXIT_FAILURE);
}

/**
 * Open a file and map it into memory.
 */
static int mmap_full_file(const char *path, void **map,
		size_t *size)
{
	int fd, ret, mmap_prot, mmap_flags;
	struct stat file_status;

	mmap_prot = PROT_READ;
	mmap_flags = MAP_PRIVATE;
	ret = open(path, O_RDONLY, 0);
	if (ret < 0) {
		fprintf(stderr, "open: %s\n", strerror(errno));
		return ret;
	}
	fd = ret;
	if (fstat(fd, &file_status) < 0) {
		ret = -1;
		fprintf(stderr, "fstat: %s\n", strerror(errno));
		goto out;
	}
	*size = file_status.st_size;
	if (!*size) {
		fprintf(stderr, "can not add empty file: %s\n", path);
		goto out;
	}
	*map = mmap(NULL, *size, mmap_prot, mmap_flags, fd, 0);
	if (*map == MAP_FAILED) {
		fprintf(stderr, "map failed: %s\n", path);
		*map = NULL;
		goto out;
	}
	ret = 1;
out:
	close(fd);
	return ret;
}


static int add_file(char *name)
{
	int ret;
	struct osl_object objs[NUM_OT_COLUMNS] = {
		[OTC_NAME] = {
			.data = name,
			.size = strlen(name) + 1
		},
	};
	printf("%s\n", name);
	ret = mmap_full_file(name, &objs[OTC_DATA].data,
		&objs[OTC_DATA].size);
	if (ret < 0)
		return ret;
	return osl_add_row(table, objs);
}

static int populate_table(const char *dirname)
{
	struct dirent *entry;
	DIR *dir;
	int ret = chdir(dirname);

	if (ret < 0) {
		fprintf(stderr, "chdir: %s\n", strerror(errno));
		exit(EXIT_FAILURE);
	}
	dir = opendir(".");
	if (!dir) {
		fprintf(stderr, "opendir: %s\n", strerror(errno));
		exit(EXIT_FAILURE);
	}
	while ((entry = readdir(dir))) {
		mode_t m;
		struct stat s;

		if (!strcmp(entry->d_name, "."))
			continue;
		if (!strcmp(entry->d_name, ".."))
			continue;
		if (lstat(entry->d_name, &s) == -1)
			continue;
		m = s.st_mode;
		if (!S_ISREG(m))
			continue;
		ret = add_file(entry->d_name);
		if (ret < 0)
			goto out;
	}
	ret = 1;
out:
	closedir(dir);
	return ret;
}

static int com_create(int argc, char **argv)
{
	struct stat statbuf;
	int ret;

	if (argc != 3)
		print_usage_and_die();
	if (lstat(argv[2], &statbuf) == -1) {
		fprintf(stderr, "no such dir: %s\n", argv[2]);
		exit(EXIT_FAILURE);
	}
	if (!S_ISDIR(statbuf.st_mode)) {
		fprintf(stderr, "not a dir: %s\n", argv[2]);
		exit(EXIT_FAILURE);
	}
	tar_table_desc.dir = argv[1];
	ret = osl_create_table(&tar_table_desc);
	if (ret < 0) {
		fprintf(stderr, "failed to create table\n");
		exit(EXIT_FAILURE);

	}
	ret = osl_open_table(&tar_table_desc, &table);
	if (ret < 0) {
		fprintf(stderr, "osl_open_table: %s\n", osl_strerror(-ret));
		exit(EXIT_FAILURE);
	}
	ret = populate_table(argv[2]);
	osl_close_table(table, OSL_MARK_CLEAN);
	return ret < 0? EXIT_FAILURE : EXIT_SUCCESS;
}

/**
 * Write the whole buffer to a file descriptor.
 */
static ssize_t write_all(int fd, const void *buf, size_t size)
{
	const char *b = buf;
	while (size) {
		ssize_t ret = write(fd, b, size);
		if (ret < 0) {
			fprintf(stderr, "open: %s\n", strerror(errno));
			return ret;

		}
		b += ret;
		size -= ret;
	}
	return 1;
}

/**
 * Open a file, write the given buffer and close the file.
 */
static int write_file(const char *filename, const void *buf, size_t size)
{
	int ret, fd;

	ret = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0644);
	if (ret < 0) {
		fprintf(stderr, "open: %s\n", strerror(errno));
		return ret;

	}
	fd = ret;
	printf("%s\n", filename);
	ret = write_all(fd, buf, size);
	if (ret < 0)
		goto out;
	ret = 1;
out:
	close(fd);
	return ret;
}

static int extract_file(char *name)
{
	int ret;
	struct osl_row *row;
	struct osl_object obj = {.data = name, .size = strlen(name) + 1};

	ret = osl_get_row(table, OTC_NAME, &obj, &row);
	if (ret < 0) {
		fprintf(stderr, "osl_get_row(%s): %s\n", name,
			osl_strerror(-ret));
		return ret;
	}
	ret = osl_get_object(table, row, OTC_DATA, &obj);
	if (ret < 0) {
		fprintf(stderr, "osl_get_object: %s\n", osl_strerror(-ret));
		return ret;
	}
	return write_file(name, obj.data, obj.size);
}

static int com_extract(int argc, char **argv)
{
	int i, ret;

	if (argc < 3)
		print_usage_and_die();
	tar_table_desc.dir = argv[1];
	ret = osl_open_table(&tar_table_desc, &table);
	if (ret < 0) {
		fprintf(stderr, "osl_open_table: %s\n", osl_strerror(-ret));
		exit(EXIT_FAILURE);

	}
	for (i = 2; i < argc; i++) {
		ret = extract_file(argv[i]);
		if (ret < 0)
			goto out;
	}
out:
	osl_close_table(table, OSL_MARK_CLEAN);
	return ret;
}

static int list_entry(struct osl_row *row, void *data)
{
	struct osl_object obj;
	int ret = osl_get_object(table, row, OTC_NAME, &obj);
	if (ret < 0) {
		fprintf(stderr, "osl_get_object: %s\n", osl_strerror(-ret));
		return ret;
	}
	printf("%s\n", (char *)obj.data);
	return 1;
}

static int com_list(int argc, char **argv)
{
	int ret;

	if (argc != 2)
		print_usage_and_die();
	tar_table_desc.dir = argv[1];
	ret = osl_open_table(&tar_table_desc, &table);
	if (ret < 0) {
		fprintf(stderr, "osl_open_table: %s\n", osl_strerror(-ret));
		exit(EXIT_FAILURE);

	}
	ret = osl_rbtree_loop(table, OTC_NAME, NULL, list_entry);
	osl_close_table(table, OSL_MARK_CLEAN);
	return ret;
}

/**
 * The osltar main funcion.
 *
 * \param argc Usual argument count.
 * \param argv Usual argument vector.
 */
int main(int argc, char **argv)
{
	if (argc < 2)
		print_usage_and_die();
	if (!strcmp(argv[1], "c"))
		return com_create(argc - 1, argv + 1);
	if (!strcmp(argv[1], "x"))
		return com_extract(argc - 1, argv + 1);
	if (!strcmp(argv[1], "t"))
		return com_list(argc - 1, argv + 1);
	print_usage_and_die();
	exit(EXIT_FAILURE);

}