/*
Copyright (C) 2017 Paweł Redman

This program 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 (at your option) any later version.

This program 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 this program; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
*/

#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#include <stdio.h>
#include <errno.h>
#include <stdarg.h>

#include <netinet/in.h>
#include <netinet/udp.h>
#include <sys/socket.h>
#include <unistd.h>

#include <pthread.h>

#include "eli.h"

#define eprintf(fmt, ...) fprintf(stderr, fmt, ##__VA_ARGS__)
#define DEBUG(fmt, ...) fprintf(stderr, "%s: " fmt, __func__, ##__VA_ARGS__)

#define LOCALHOST_NETWORK 0x7F000000
#define LOCALHOST_MASK    0xFF000000

#define REQUEST_HEADER "query "
#define REQUEST_HEADER_LEN (sizeof(REQUEST_HEADER) - 1)
#define RESPONSE_HEADER "reply "

// main.c

extern int server_sockfd;

uint64_t get_time(void);

#define TIME_SECOND (1000000000llu)
#define TIME_MINUTE (60 * TIME_SECOND)
#define TIME_HOUR   (60 * TIME_MINUTE)

// shared

typedef struct job_s job_t;

// database.c

enum {
	DB_INVALID,
	DB_IN_PROGRESS,
	DB_VALID
};

typedef struct {
	int state;
	uint64_t exp_time;
	char *data;
} db_entry_field;

typedef struct {
	uint32_t ipv4;

	db_entry_field revdns, whois;

	bool cached_result_valid;
	int cached_result;

	job_t *waiting_jobs;

	eli_header ht_chain;
	pthread_mutex_t mutex;
} db_entry;

db_entry *db_find(uint32_t ipv4);
void db_destroy(void);
void db_invalidate_cached_results(void);

// worker.c

typedef enum {
	JOB_REVDNS,
	JOB_WHOIS,
	JOB_REPLY,
} job_type_t;

struct job_s {
	job_type_t type;

	db_entry *entry;
	struct sockaddr_in ret_addr; // for JOB_REPLY
	uint32_t ipv4; // for other jobs

	eli_header queue_list, waiting_list;
};

job_t *job_create(job_type_t type, db_entry *entry);
void job_destroy(job_t *job);
void job_enqueue(job_t *job);
void job_quit(void);
void *worker_main(void *unused);

// lexer.c

typedef struct {
	char *data;
	size_t size, alloc;
} vstr_t;

#define VSTR_INITIALIZER ((vstr_t){NULL, 0, 0})

void vstr_init(vstr_t *vstr);
void vstr_destroy(vstr_t *vstr);
void vstr_clear(vstr_t *vstr);
int vstr_putc(vstr_t *vstr, char ch);
int vstr_cmp(vstr_t *vstr, const char *str);
char *vstr_strdup(vstr_t *vstr);
char *vstr_to_cstr(vstr_t *vstr);

#define LEXER_BUFFER 1024

typedef struct {
	int error;
	const char *path;
	FILE *fp;
	bool eof;

	vstr_t *token;
	char buf[LEXER_BUFFER];
	char *buf_c, *buf_e;

	size_t cc, lc, Cc; // character, line, and column counters
	char last;

	bool in_token;
	bool in_quote;
	bool in_comment;
} lexer_state_t;

int lexer_open(lexer_state_t *ls, const char *path, vstr_t *token);
void lexer_close(lexer_state_t *ls);
int lexer_get_token(lexer_state_t *ls);
void lexer_perror(lexer_state_t *ls, const char *fmt, ...);
void lexer_perror_eg(lexer_state_t *ls, const char *expected);

// lists.c

int lists_load(const char *file, size_t depth);
int lists_reload(const char *file);
void lists_destroy(void);
int lists_test(const char *revdns, const char *whois);