/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 *
 * res_odbc.c <ODBC resource manager>
 * Copyright (C) 2004 - 2005 Anthony Minessale II <anthmct@yahoo.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */


/*! \file
 *
 * \brief ODBC resource manager
 * 
 * \arg See also: \ref cdr_odbc
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision$")

#include "asterisk/file.h"
#include "asterisk/logger.h"
#include "asterisk/channel.h"
#include "asterisk/config.h"
#include "asterisk/options.h"
#include "asterisk/pbx.h"
#include "asterisk/module.h"
#include "asterisk/cli.h"
#include "asterisk/lock.h"
#include "asterisk/res_odbc.h"
#define MAX_ODBC_HANDLES 25

struct odbc_list
{
	char name[80];
	odbc_obj *obj;
	int used;
};

static struct odbc_list ODBC_REGISTRY[MAX_ODBC_HANDLES];


static void odbc_destroy(void)
{
	int x = 0;

	for (x = 0; x < MAX_ODBC_HANDLES; x++) {
		if (ODBC_REGISTRY[x].obj) {
			destroy_odbc_obj(&ODBC_REGISTRY[x].obj);
			ODBC_REGISTRY[x].obj = NULL;
		}
	}
}

static odbc_obj *odbc_read(struct odbc_list *registry, const char *name)
{
	int x = 0;
	for (x = 0; x < MAX_ODBC_HANDLES; x++) {
		if (registry[x].used && !strcmp(registry[x].name, name)) {
			return registry[x].obj;
		}
	}
	return NULL;
}

static int odbc_write(struct odbc_list *registry, char *name, odbc_obj *obj)
{
	int x = 0;
	for (x = 0; x < MAX_ODBC_HANDLES; x++) {
		if (!registry[x].used) {
			ast_copy_string(registry[x].name, name, sizeof(registry[x].name));
			registry[x].obj = obj;
			registry[x].used = 1;
			return 1;
		}
	}
	return 0;
}

static void odbc_init(void)
{
	int x = 0;
	for (x = 0; x < MAX_ODBC_HANDLES; x++) {
		memset(&ODBC_REGISTRY[x], 0, sizeof(struct odbc_list));
	}
}

static char *tdesc = "ODBC Resource";
/* internal stuff */

SQLHSTMT odbc_prepare_and_execute(odbc_obj *obj, SQLHSTMT (*prepare_cb)(odbc_obj *obj, void *data), void *data)
{
	int res = 0, i, attempt;
	SQLINTEGER nativeerror=0, numfields=0;
	SQLSMALLINT diagbytes=0;
	unsigned char state[10], diagnostic[256];
	SQLHSTMT stmt;

	for (attempt = 0; attempt < 2; attempt++) {
		/* This prepare callback may do more than just prepare -- it may also
		 * bind parameters, bind results, etc.  The real key, here, is that
		 * when we disconnect, all handles become invalid for most databases.
		 * We must therefore redo everything when we establish a new
		 * connection. */
		stmt = prepare_cb(obj, data);

		if (stmt) {
			res = SQLExecute(stmt);
			if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO) && (res != SQL_NO_DATA)) {
				if (res == SQL_ERROR) {
					SQLGetDiagField(SQL_HANDLE_STMT, stmt, 1, SQL_DIAG_NUMBER, &numfields, SQL_IS_INTEGER, &diagbytes);
					for (i=0; i< numfields + 1; i++) {
						SQLGetDiagRec(SQL_HANDLE_STMT, stmt, i + 1, state, &nativeerror, diagnostic, sizeof(diagnostic), &diagbytes);
						ast_log(LOG_WARNING, "SQL Execute returned an error %d: %s: %s (%d)\n", res, state, diagnostic, diagbytes);
						if (i > 10) {
							ast_log(LOG_WARNING, "Oh, that was good.  There are really %d diagnostics?\n", (int)numfields);
							break;
						}
					}
				}

				ast_log(LOG_WARNING, "SQL Execute error %d! Attempting a reconnect...\n", res);
				SQLFreeHandle(SQL_HANDLE_STMT, stmt);

				ast_mutex_lock(&obj->lock);
				obj->up = 0;
				ast_mutex_unlock(&obj->lock);
				odbc_obj_disconnect(obj);
				odbc_obj_connect(obj);
				continue;
			}
			break;
		}
	}

	return stmt;
}

int odbc_smart_execute(odbc_obj *obj, SQLHSTMT stmt) 
{
	int res = 0, i;
	SQLINTEGER nativeerror=0, numfields=0;
	SQLSMALLINT diagbytes=0;
	unsigned char state[10], diagnostic[256];

	res = SQLExecute(stmt);
	if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO) && (res != SQL_NO_DATA)) {
		if (res == SQL_ERROR) {
			SQLGetDiagField(SQL_HANDLE_STMT, stmt, 1, SQL_DIAG_NUMBER, &numfields, SQL_IS_INTEGER, &diagbytes);
			for (i=0; i< numfields + 1; i++) {
				SQLGetDiagRec(SQL_HANDLE_STMT, stmt, i + 1, state, &nativeerror, diagnostic, sizeof(diagnostic), &diagbytes);
				ast_log(LOG_WARNING, "SQL Execute returned an error %d: %s: %s (%d)\n", res, state, diagnostic, diagbytes);
				if (i > 10) {
					ast_log(LOG_WARNING, "Oh, that was good.  There are really %d diagnostics?\n", (int)numfields);
					break;
				}
			}
		}
/*
		ast_log(LOG_WARNING, "SQL Execute error %d! Attempting a reconnect...\n", res);
		ast_mutex_lock(&obj->lock);
		obj->up = 0;
		ast_mutex_unlock(&obj->lock);
		odbc_obj_disconnect(obj);
		odbc_obj_connect(obj);
		res = SQLExecute(stmt);
*/
	}
	
	return res;
}


int odbc_smart_direct_execute(odbc_obj *obj, SQLHSTMT stmt, char *sql) 
{
	int res = 0;

	res = SQLExecDirect (stmt, (unsigned char *)sql, SQL_NTS);
	if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
		ast_log(LOG_WARNING, "SQL Execute error! Attempting a reconnect...\n");
		ast_mutex_lock(&obj->lock);
		obj->up = 0;
		ast_mutex_unlock(&obj->lock);
		odbc_obj_disconnect(obj);
		odbc_obj_connect(obj);
		res = SQLExecDirect (stmt, (unsigned char *)sql, SQL_NTS);
	}
	
	return res;
}

int odbc_sanity_check(odbc_obj *obj) 
{
	char *test_sql = "select 1";
	SQLHSTMT stmt;
	int res = 0;

	ast_mutex_lock(&obj->lock);
	if(obj->up) { /* so you say... let's make sure */
		res = SQLAllocHandle (SQL_HANDLE_STMT, obj->con, &stmt);
		if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
			obj->up = 0; /* Liar!*/
		} else {
			res = SQLPrepare(stmt, (unsigned char *)test_sql, SQL_NTS);
			if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
				obj->up = 0; /* Liar!*/
			} else {
				res = SQLExecute(stmt);
				if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
					obj->up = 0; /* Liar!*/
				}
			}
		}
		SQLFreeHandle (SQL_HANDLE_STMT, stmt);
	}
	ast_mutex_unlock(&obj->lock);

	if(!obj->up) { /* Try to reconnect! */
		ast_log(LOG_WARNING, "Connection is down attempting to reconnect...\n");
		odbc_obj_disconnect(obj);
		odbc_obj_connect(obj);
	}
	return obj->up;
}

static int load_odbc_config(void)
{
	static char *cfg = "res_odbc.conf";
	struct ast_config *config;
	struct ast_variable *v;
	char *cat, *dsn, *username, *password;
	int enabled;
	int connect = 0;
	char *env_var;

	odbc_obj *obj;

	config = ast_config_load(cfg);
	if (config) {
		for (cat = ast_category_browse(config, NULL); cat; cat=ast_category_browse(config, cat)) {
			if (!strcmp(cat, "ENV")) {
				for (v = ast_variable_browse(config, cat); v; v = v->next) {
					env_var = malloc(strlen(v->name) + strlen(v->value) + 2);
					if (env_var) {
						sprintf(env_var, "%s=%s", v->name, v->value);
						ast_log(LOG_NOTICE, "Adding ENV var: %s=%s\n", v->name, v->value);
						putenv(env_var);
						free(env_var);
					}
				}

			cat = ast_category_browse(config, cat);
			}

			dsn = username = password = NULL;
			enabled = 1;
			connect = 0;
			for (v = ast_variable_browse(config, cat); v; v = v->next) {
				if (!strcmp(v->name, "enabled"))
					enabled = ast_true(v->value);
				if (!strcmp(v->name, "pre-connect"))
					connect = ast_true(v->value);
				if (!strcmp(v->name, "dsn"))
					dsn = v->value;
				if (!strcmp(v->name, "username"))
					username = v->value;
				if (!strcmp(v->name, "password"))
					password = v->value;
			}

			if (enabled && dsn) {
				obj = new_odbc_obj(cat, dsn, username, password);
				if (obj) {
					register_odbc_obj(cat, obj);
					ast_log(LOG_NOTICE, "registered database handle '%s' dsn->[%s]\n", cat, obj->dsn);
					if (connect) {
						odbc_obj_connect(obj);
					}
				} else {
					ast_log(LOG_WARNING, "Addition of obj %s failed.\n", cat);
				}

			}
		}
		ast_config_destroy(config);
	}
	return 0;
}

int odbc_dump_fd(int fd, odbc_obj *obj)
{
	/* make sure the connection is up before we lie to our master.*/
	odbc_sanity_check(obj);
	ast_cli(fd, "Name: %s\nDSN: %s\nConnected: %s\n\n", obj->name, obj->dsn, obj->up ? "yes" : "no");
	return 0;
}

static int odbc_connect_usage(int fd)
{
	ast_cli(fd, "usage odbc connect <DSN>\n");
	return 0;
}

static int odbc_disconnect_usage(int fd)
{
	ast_cli(fd, "usage odbc disconnect <DSN>\n");
	return 0;
}

static int odbc_show_command(int fd, int argc, char **argv)
{
	odbc_obj *obj;
	int x = 0;
	
	if (!strcmp(argv[1], "show")) {
		if (!argv[2] || (argv[2] && !strcmp(argv[2], "all"))) {
			for (x = 0; x < MAX_ODBC_HANDLES; x++) {
				if (!ODBC_REGISTRY[x].used)
					break;
				if (ODBC_REGISTRY[x].obj)
					odbc_dump_fd(fd, ODBC_REGISTRY[x].obj);
			}
		} else {
			obj = odbc_read(ODBC_REGISTRY, argv[2]);
			if (obj)
				odbc_dump_fd(fd, obj);
		}
	}
	return 0;
}

static int odbc_disconnect_command(int fd, int argc, char **argv)
{
	odbc_obj *obj;
	if (!strcmp(argv[1], "disconnect")) {
		if (!argv[2])
			return odbc_disconnect_usage(fd);

		obj = odbc_read(ODBC_REGISTRY, argv[2]);
		if (obj) {
			odbc_obj_disconnect(obj);
		}
	} 
	return 0;
}

static int odbc_connect_command(int fd, int argc, char **argv)
{
	odbc_obj *obj;
	if (!argv[1])
		return odbc_connect_usage(fd);

	if (!strcmp(argv[1], "connect") || !strcmp(argv[1], "disconnect")) {
		if (!argv[2])
			return odbc_connect_usage(fd);

		obj = odbc_read(ODBC_REGISTRY, argv[2]);
		if (obj) {
			odbc_obj_connect(obj);
		}
	}
	return 0;
}


static char connect_usage[] =
"Usage: odbc connect <DSN>\n"
"       Connect to ODBC DSN\n";

static char disconnect_usage[] =
"Usage: odbc connect <DSN>\n"
"       Disconnect from ODBC DSN\n";

static char show_usage[] =
"Usage: odbc show {DSN}\n"
"       Show ODBC {DSN}\n"
"       Specifying DSN will show that DSN else, all DSNs are shown\n";

static struct ast_cli_entry odbc_connect_struct =
        { { "odbc", "connect", NULL }, odbc_connect_command, "Connect to ODBC DSN", connect_usage };


static struct ast_cli_entry odbc_disconnect_struct =
        { { "odbc", "disconnect", NULL }, odbc_disconnect_command, "Disconnect from ODBC DSN", disconnect_usage };

static struct ast_cli_entry odbc_show_struct =
        { { "odbc", "show", NULL }, odbc_show_command, "Show ODBC DSN(s)", show_usage };

/* api calls */

int register_odbc_obj(char *name, odbc_obj *obj)
{
	if (obj != NULL)
		return odbc_write(ODBC_REGISTRY, name, obj);
	return 0;
}

odbc_obj *fetch_odbc_obj(const char *name, int check)
{
	odbc_obj *obj = NULL;
	if((obj = (odbc_obj *) odbc_read(ODBC_REGISTRY, name))) {
		if(check)
			odbc_sanity_check(obj);
	}
	return obj;
}

odbc_obj *new_odbc_obj(char *name, char *dsn, char *username, char *password)
{
	static odbc_obj *new;

	if (!(new = calloc(1, sizeof(*new))) || 
	    !(new->name = malloc(strlen(name) + 1)) || 
	    !(new->dsn = malloc(strlen(dsn) + 1)))
	    	goto cleanup;

	if (username) {
		if (!(new->username = malloc(strlen(username) + 1)))
			goto cleanup;
		strcpy(new->username, username);
	}

	if (password) {
		if (!(new->password = malloc(strlen(password) + 1)))
			goto cleanup;
		strcpy(new->password, password);
	}

	strcpy(new->name, name);
	strcpy(new->dsn, dsn);
	new->env = SQL_NULL_HANDLE;
	new->up = 0;
	ast_mutex_init(&new->lock);
	return new;

cleanup:
	if (new) {
		free(new->name);
		free(new->dsn);
		free(new->username);
		free(new->password);

		free(new);	
	}

	return NULL;
}

void destroy_odbc_obj(odbc_obj **obj)
{
	odbc_obj_disconnect(*obj);

	ast_mutex_lock(&(*obj)->lock);
	SQLFreeHandle(SQL_HANDLE_STMT, (*obj)->stmt);
	SQLFreeHandle(SQL_HANDLE_DBC, (*obj)->con);
	SQLFreeHandle(SQL_HANDLE_ENV, (*obj)->env);

	free((*obj)->name);
	free((*obj)->dsn);
	if ((*obj)->username)
		free((*obj)->username);
	if ((*obj)->password)
		free((*obj)->password);
	ast_mutex_unlock(&(*obj)->lock);
	ast_mutex_destroy(&(*obj)->lock);
	free(*obj);
}

odbc_status odbc_obj_disconnect(odbc_obj *obj)
{
	int res;
	ast_mutex_lock(&obj->lock);

	res = SQLDisconnect(obj->con);


	if (res == ODBC_SUCCESS) {
		ast_log(LOG_WARNING, "res_odbc: disconnected %d from %s [%s]\n", res, obj->name, obj->dsn);
	} else {
		ast_log(LOG_WARNING, "res_odbc: %s [%s] already disconnected\n",
		obj->name, obj->dsn);
	}
	obj->up = 0;
	ast_mutex_unlock(&obj->lock);
	return ODBC_SUCCESS;
}

odbc_status odbc_obj_connect(odbc_obj *obj)
{
	int res;
	SQLINTEGER err;
	short int mlen;
	unsigned char msg[200], stat[10];

	ast_mutex_lock(&obj->lock);

	if (obj->env == SQL_NULL_HANDLE) {
		res = SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &obj->env);

		if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
			if (option_verbose > 3)
				ast_log(LOG_WARNING, "res_odbc: Error AllocHandle\n");
			ast_mutex_unlock(&obj->lock);
			return ODBC_FAIL;
		}

		res = SQLSetEnvAttr(obj->env, SQL_ATTR_ODBC_VERSION, (void *) SQL_OV_ODBC3, 0);

		if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
			if (option_verbose > 3)
				ast_log(LOG_WARNING, "res_odbc: Error SetEnv\n");
			SQLFreeHandle(SQL_HANDLE_ENV, obj->env);
			ast_mutex_unlock(&obj->lock);
			return ODBC_FAIL;
		}

		res = SQLAllocHandle(SQL_HANDLE_DBC, obj->env, &obj->con);

		if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {

			if (option_verbose > 3)
				ast_log(LOG_WARNING, "res_odbc: Error AllocHDB %d\n", res);
			SQLFreeHandle(SQL_HANDLE_ENV, obj->env);

			ast_mutex_unlock(&obj->lock);
			return ODBC_FAIL;
		}
		SQLSetConnectAttr(obj->con, SQL_LOGIN_TIMEOUT, (SQLPOINTER *) 10, 0);
	}
	if(obj->up) {
		odbc_obj_disconnect(obj);
		ast_log(LOG_NOTICE,"Re-connecting %s\n", obj->name);
	}

	ast_log(LOG_NOTICE, "Connecting %s\n", obj->name);

	res = SQLConnect(obj->con,
		   (SQLCHAR *) obj->dsn, SQL_NTS,
		   (SQLCHAR *) obj->username, SQL_NTS,
		   (SQLCHAR *) obj->password, SQL_NTS);

	if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
		SQLGetDiagRec(SQL_HANDLE_DBC, obj->con, 1, stat, &err, msg, 100, &mlen);
		SQLFreeHandle(SQL_HANDLE_ENV, obj->env);
		ast_mutex_unlock(&obj->lock);
		ast_log(LOG_WARNING, "res_odbc: Error SQLConnect=%d errno=%d %s\n", res, (int)err, msg);
		return ODBC_FAIL;
	} else {

		ast_log(LOG_NOTICE, "res_odbc: Connected to %s [%s]\n", obj->name, obj->dsn);
		obj->up = 1;
	}

	ast_mutex_unlock(&obj->lock);
	return ODBC_SUCCESS;
}

STANDARD_LOCAL_USER;

LOCAL_USER_DECL;

int unload_module(void)
{
	STANDARD_HANGUP_LOCALUSERS;
	odbc_destroy();
	ast_cli_unregister(&odbc_disconnect_struct);
	ast_cli_unregister(&odbc_connect_struct);
	ast_cli_unregister(&odbc_show_struct);
	ast_log(LOG_NOTICE, "res_odbc unloaded.\n");
	return 0;
}

int load_module(void)
{
	odbc_init();
	load_odbc_config();
	ast_cli_register(&odbc_disconnect_struct);
	ast_cli_register(&odbc_connect_struct);
	ast_cli_register(&odbc_show_struct);
	ast_log(LOG_NOTICE, "res_odbc loaded.\n");
	return 0;
}

char *description(void)
{
	return tdesc;
}

int usecount(void)
{
	int res;
	STANDARD_USECOUNT(res);
	return res;
}

char *key()
{
	return ASTERISK_GPL_KEY;
}