/*
 * Copyright 2017 Yann Weber
 * 
 * This file is part of Ttail.
 * 
 * Ttail 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 3 of the License, or
 * any later version.
 * 
 * Ttail 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 Ttail.  If not, see <http://www.gnu.org/licenses/>.
 */
#ifndef _ttail_search_files_h__
#define _ttail_search_files_h__

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

typedef struct _ttail_search_file_s ttail_search_file_t;


struct _ttail_files_off_s
{
	size_t id;
	off_t off;
};

typedef struct _ttail_files_off_s ttail_files_off_t;

/*<! Private search session for logfiles */
struct _ttail_search_file_s
{
	/*<! logfile sizes */
	off_t *file_sz;
	#ifdef TTAIL_HUGE_FILE
	/*<! Shift width to apply on size to compute stuff */
	short sz_div;
	#endif
	/*<! Computed files start size
	 *@todo delete, useless
	 */
	off_t *vfile;
	/*<! Computed file sizes sum 
	 *@todo delete useless
	 */
	off_t vsz;
	/*<! Computed position 
	 *@todo delete, useless
	 */
	off_t vpos;

	/*<! buffer for ttail_getiline() macro */
	char *buf;
	/*<! buffer size for ttail_getiline() macro */
	size_t buf_sz;
	
	/*<! Closest offset to min date*/
	ttail_files_off_t off_min;
	/*<! Closest offset to max date*/
	ttail_files_off_t off_max;
};

#include "config.h"
#include "ttail.h"
#include "ttail_search.h"

/**@brief Convenient wrapper for getline
 *@param ttail_t* TTAIL
 *@param size_t ID file id
 *@return @ref getline()
 */
#define ttail_file_getline(TTAIL, ID) (getline(\
	&(TTAIL->session->file.buf), &(TTAIL->session->file.buf_sz),\
	TTAIL->logfile[ID]))

/*<!Accessor to getline wrapper buffer */
#define ttail_file_getline_buf(TTAIL) (TTAIL->session->file.buf)

/**@brief @ref ttail_search_closest() implementation for logfiles
 *
 *Will set struct _ttail_search_file_s.id and struct _ttail_search_file_s.off
 *@param ttail_t*
 *@return 0 if ok -1 if fatal error 1 if not found
 */
int _ttail_search_closest_files(ttail_t*);

/**@brief Output result loglines to stdout
 *@param ttail_t*
 *@param int fd
 */
void _ttail_search_print_files(ttail_t*, int);

int _ttail_search_closest_files_init(ttail_t*);
int _ttail_search_closest_files_set_fsizes(ttail_t*);

/**@brief Binary search of the last logline with a date < tm
 *@param ttail ttail_t*
 *@param tm struct tm*
 *param min short if 1 process min else process max
 *@param ftm struct tm** local variable of @ref _ttail_search_closest_files()
 *@return 0 if ok -1 if error 1 if empty result
 */
int _ttail_search_files_binary_search(ttail_t*, const struct tm*,
	const struct tm**, short);

/**@brief Binary search of the last logline with a date < tm in a file
 *
 *@note uses ttail_t session data to know where to search
 *@param ttail ttail_t*
 *@param tm struct tm*
 *@param ftm struct tm** local variable of @ref _ttail_search_closest_files()
 *param min short if 1 process min else process max
 *@return 0 if ok -1 if error 1 if empty result
 */
int _ttail_search_file_binary_search(ttail_t*, const struct tm*,
	const struct tm**, short);

/**@brief Attempt to reopen a file
 *@param ttail_t* ttail
 *@param size_t id file id in ttail
 *@return 0 on success, -1 on failure and errno is set
 *@throw EINVAL if id is too big
 */
int _ttail_file_reopen(ttail_t*, size_t);

/**@brief Set min & max date of file
 *@param ttail_t* ttail
 *@param size_t id file id in ttail
 *@param struct tm[2] will be set to min & max
 *@return 0 on success 1 if no date found or no fp -1 if error
 */
inline int _ttail_file_minmax(ttail_t*, size_t, struct tm[2]);

/**@brief Search next line
 *
 *Set f pos to next line begining and return the position
 *@param FILE* f 
 *@return -1 on error 0 on EOF else return the next line position
 *@todo change header to int _ttail_file_next_line(ttail_t, size_t, size_t*)
 */
inline long _ttail_file_next_line(FILE*);

/**@brief Search line start
 *
 *Set f pos to line begining and return the position
 *@param FILE* f 
 *@return -1 on error else return the next line position
 *@todo change header to int _ttail_file_start_line(ttail_t, size_t, size_t*)
 */
inline long _ttail_file_start_line(FILE*);

/**@brief Search last line with a date < tm from EOF
 *@param ttail ttail_t*
 *@param id size_t
 *@param tm const struct tm*
 *@return -1 on error else the offset of the line first chr
 *@todo checks
 */
inline off_t _ttail_from_search_from_end(ttail_t*, size_t, const struct tm*);

/**@brief Read a line from off and compare its date to tm
 *@param t ttail_t*
 *@param id site_t
 *@param off off_t
 *@param tm const struct tm*
 *@param res int* see return value of @ref ttail_tm_cmp()
 *@return 0 on success -1 on error 1 if no date found
 */
inline int _ttail_file_off_cmp(ttail_t*, size_t, off_t, const struct tm*, int*);

/**@brief Same than _ttail_file_off_cmp() but from current pos
 *@return 0 on success -1 on error 1 if no date found*/
inline int _ttail_file_cur_cmp(ttail_t*, size_t, const struct tm*, int*);

/**@brief Free the ttail_search_file_t session
 *@param ttail_t* ttail
 */
void _ttail_search_file_free(ttail_t*);
#endif