/*
// Copyright (c) 2010-2017 Intel Corporation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
*/

#include "cfgfile.h"

#include <rte_string_fns.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <unistd.h>

#include "parse_utils.h"
#include "log.h"
#include "quit.h"
#include "prox_compat.h"

#define UINT32_MAX_STR "4294967295"

/*
 * Allocate cfg_file structure.
 * Returns pointer to the allocated structure, NULL otherwise.
 */
struct cfg_file *cfg_open(const char *cfg_name)
{
	if (cfg_name == NULL) {
		plog_err("\tNo config file name provided\n");
		return NULL;
	}
	if (access(cfg_name, F_OK)) {
                plog_err("\tError opening config file '%s': %s\n", cfg_name, strerror(errno));
		return NULL;
	}

	FILE *pf = fopen(cfg_name, "rb");
	if (pf == NULL) {
		plog_err("\tError opening config file '%s'\n", cfg_name);
		return NULL;
	}

	struct cfg_file *pcfg = calloc(1, sizeof(struct cfg_file));

	if (pcfg == NULL) {
		fclose(pf);
		plog_err("\tCouldn't allocate memory for config file struct\n");
		return NULL;
	}

	pcfg->pfile = pf;
	pcfg->name = strdup(cfg_name);

	return pcfg;
}

/* Free memory allocated for cfg_file structure.
 * Returns 0 on success, -1 if the pointer to the pcfg is invalid */
int cfg_close(struct cfg_file *pcfg)
{
	if (pcfg == NULL) {
		return -1;
	}

	if (pcfg->name != NULL) {
		free(pcfg->name);
	}
	if (pcfg->err_section != NULL) {
		free(pcfg->err_section);
	}
	if (pcfg->pfile != NULL) {
		fclose(pcfg->pfile);
	}

	free(pcfg);
	return 0;
}

static int cfg_get_pos(struct cfg_file *pcfg, fpos_t *pos)
{
	pcfg->index_line = pcfg->line;
	return fgetpos(pcfg->pfile, pos);
}

static int cfg_set_pos(struct cfg_file *pcfg, fpos_t *pos)
{
	pcfg->line = pcfg->index_line;
	return fsetpos(pcfg->pfile, pos);
}

/*
 * Read a line from the configuration file.
 * Returns: on success length of the line read from the file is returned,
 *          0 to indicate End of File,
 *         -1 in case of wrong function parameters
 */
static int cfg_get_line(struct cfg_file *pcfg, char *buffer, unsigned len, int raw_lines)
{
	char *ptr;

	if (pcfg == NULL || pcfg->pfile == NULL || buffer == NULL || len == 0) {
		return -1;
	}

	do {
		ptr = fgets(buffer, len, pcfg->pfile);
		if (ptr == NULL) {
			return 0; /* end of file */
		}
		++pcfg->line;

		if (raw_lines) {
			break;
		}

		/* remove comments */
		ptr = strchr(buffer, ';');
		if (ptr != NULL) {
			*ptr = '\0';
		}
		else {
			ptr = strchr(buffer, '\0');
		}

		/* remove trailing spaces */
		if (ptr != buffer) {
			ptr--;
			while (isspace(*ptr)) {
				*ptr = '\0';
				ptr--;
			}
		}

		ptr = buffer;
		/* remove leading spaces */
		while (*ptr && isspace(*ptr)) {
			++ptr;
		}
		if (ptr != buffer) {
			strcpy(buffer, ptr);
			ptr = buffer;
		}
	}
	while (*ptr == '\0'); /* skip empty strings */

	return strlen(buffer);
}

/*
 * Checks if buffer contains section name specified by the cfg_section pointer.
 * Returns NULL if section name does not match, cfg_section pointer otherwise
 */
static struct cfg_section *cfg_check_section(char *buffer, struct cfg_section *psec)
{
	char *pend;
	unsigned len;
	static const char *valid = "0123456789,hs- \t";

	pend = strchr(buffer, ']');
	if (pend == NULL) {
		return NULL; /* ']' not found: invalid section name */
	}

	*pend = '\0';

	/* check if section is indexed */
	pend = strchr(psec->name, '#');
	if (pend == NULL) {
		return (strcmp(buffer, psec->name) == 0) ? psec : NULL;
	}

	/* get section index */
	len = pend - psec->name;
	if (strncmp(buffer, psec->name, len) != 0) {
		return NULL;
	}
	pend = buffer + len;
	if (*pend == '\0') {
		return NULL;
	}

	/* only numeric characters are valid for section index */
	char val[MAX_CFG_STRING_LEN];
	if (pend[0] == '$') {
		if (parse_vars(val, sizeof(val), pend))
			return NULL;
	} else
		prox_strncpy(val, pend, sizeof(val));

	for (len = 0; val[len] != '\0'; ++len) {
		if (strchr(valid, val[len]) == NULL) {
			return NULL;
		}
	}

	psec->nbindex = parse_list_set(psec->indexp, pend, MAX_INDEX);
	PROX_PANIC(psec->nbindex == -1, "\t\tError in cfg_check_section('%s'): %s\n", buffer, get_parse_err());

	for (int i = 0; i < psec->nbindex; ++i) {
		psec->indexp[i] |= CFG_INDEXED;
	}

	return psec;
}

static char *cfg_get_section_name(struct cfg_section *psec)
{
	char *name;

	if (!(psec->indexp[0] & CFG_INDEXED)) {
		return strdup(psec->name);
	}

	name = malloc(strlen(psec->name) + strlen(UINT32_MAX_STR));
	if (name != NULL) {
		strcpy(name, psec->name);
		char *pidx = strchr(name, '#');
		if (pidx != NULL) {
			sprintf(pidx, "%u", psec->indexp[0] & ~CFG_INDEXED);
		}
	}
	return name;
}

/*
 * Reads configuration file and parses section specified by psec pointer.
 * Returns 0 on success, -1 otherwise
 */
int cfg_parse(struct cfg_file *pcfg, struct cfg_section *psec)
{
	int error;
	unsigned entry = 0;
	fpos_t pos;
	int index_count = 0;
	struct cfg_section *section = NULL;
	char buffer[sizeof(pcfg->cur_line)] = {0};

	if (pcfg == NULL || psec == NULL) {
		return -1;
	}

	pcfg->line = 0;
	fseek(pcfg->pfile, 0, SEEK_SET);

	/* read configuration file and parse section specified by psec pointer */
	while (1) {
		if (psec->raw_lines) {
			/* skip until section starts */
			char *lines = pcfg->cur_line;
			size_t max_len = sizeof(pcfg->cur_line);
			char *ret;

			do {
				ret = fgets(lines, max_len, pcfg->pfile);
				if (ret && *ret == '[') {
					section = cfg_check_section(lines + 1, psec);
				}
			} while (!section && ret);

			if (!ret)
				return 0;

			do {

				ret = fgets(buffer, sizeof(buffer), pcfg->pfile);
				if (ret && *ret != '[') {
					size_t l = strlen(buffer);
					prox_strncpy(lines, buffer, max_len);
					max_len -= l;
					lines += l;
				}
			} while ((ret && *ret != '['));

			if (section != NULL) {
				error = section->parser(section->indexp[index_count], pcfg->cur_line, section->data);
				if (error != 0) {
					section->error = error;
					/* log only the very first error */
					if (!pcfg->err_section) {
						pcfg->err_line = pcfg->line;
						pcfg->err_entry = entry;
						pcfg->err_section = cfg_get_section_name(section);
					}
					return 0;
				}
				++entry;
			}
			return 0;
		}

		while (cfg_get_line(pcfg, buffer, MAX_CFG_STRING_LEN, psec->raw_lines) > 0) {
			prox_strncpy(pcfg->cur_line, buffer, sizeof(pcfg->cur_line));
			if (*buffer == '[') {
				if (index_count + 1 < psec->nbindex) {
					// Need to loop - go back to recorded postion in file
					cfg_set_pos(pcfg, &pos);
					++index_count;
					continue;
				}
				else {
					section = cfg_check_section(buffer + 1, psec);
					entry = 0;
					index_count = 0;
					cfg_get_pos(pcfg, &pos);
					continue;
				}
			}
			/* call parser procedure for each line in the section */
			if (section != NULL) {
				error = section->parser(section->indexp[index_count], buffer, section->data);
				if (error != 0) {
					section->error = error;
					/* log only the very first error */
					if (!pcfg->err_section) {
						pcfg->err_line = pcfg->line;
						pcfg->err_entry = entry;
						pcfg->err_section = cfg_get_section_name(section);
					}
					return 0;
				}
				++entry;
			}
		}
		if (index_count + 1 < psec->nbindex) {
			// Last core config contained multiple cores - loop back
			cfg_set_pos(pcfg, &pos);
			++index_count;
		}
		else {
			break;
		}
	}
	return 0;
}