/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (c) 2003-2006 Tilghman Lesher.  All rights reserved.
 *
 * Tilghman Lesher <app_cut__v003@the-tilghman.com>
 *
 * This code is released by the author with no restrictions on usage.
 *
 * 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.
 *
 */

/*! \file
 * 
 * \brief CUT function
 *
 * \author Tilghman Lesher <app_cut__v003@the-tilghman.com>
 *
 * \ingroup functions
 */

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision$")

#include "asterisk/file.h"
#include "asterisk/channel.h"
#include "asterisk/pbx.h"
#include "asterisk/module.h"
#include "asterisk/app.h"

/*** DOCUMENTATION
	<function name="SORT" language="en_US">
		<synopsis>
			Sorts a list of key/vals into a list of keys, based upon the vals.	
		</synopsis>
		<syntax>
			<parameter name="keyval" required="true" argsep=":">
				<argument name="key1" required="true" />
				<argument name="val1" required="true" />
			</parameter>
			<parameter name="keyvaln" multiple="true" argsep=":">
				<argument name="key2" required="true" />
				<argument name="val2" required="true" />
			</parameter>
		</syntax>
		<description>
			<para>Takes a comma-separated list of keys and values, each separated by a colon, and returns a
			comma-separated list of the keys, sorted by their values.  Values will be evaluated as
			floating-point numbers.</para>
		</description>
	</function>
	<function name="CUT" language="en_US">
		<synopsis>
			Slices and dices strings, based upon a named delimiter.		
		</synopsis>
		<syntax>
			<parameter name="varname" required="true">
				<para>Variable you want cut</para>
			</parameter>
			<parameter name="char-delim" required="true">
				<para>Delimiter, defaults to <literal>-</literal></para>
			</parameter>
			<parameter name="range-spec" required="true">
				<para>Number of the field you want (1-based offset), may also be specified as a range (with <literal>-</literal>)
				or group of ranges and fields (with <literal>&amp;</literal>)</para>
			</parameter>
		</syntax>
		<description>
			<para>Cut out information from a string (<replaceable>varname</replaceable>), based upon a named delimiter.</para>
		</description>	
	</function>
 ***/

struct sortable_keys {
	char *key;
	float value;
};

static int sort_subroutine(const void *arg1, const void *arg2)
{
	const struct sortable_keys *one=arg1, *two=arg2;
	if (one->value < two->value)
		return -1;
	else if (one->value == two->value)
		return 0;
	else
		return 1;
}

#define ERROR_NOARG	(-1)
#define ERROR_NOMEM	(-2)
#define ERROR_USAGE	(-3)

static int sort_internal(struct ast_channel *chan, char *data, char *buffer, size_t buflen)
{
	char *strings, *ptrkey, *ptrvalue;
	int count=1, count2, element_count=0;
	struct sortable_keys *sortable_keys;

	*buffer = '\0';

	if (!data)
		return ERROR_NOARG;

	strings = ast_strdupa(data);

	for (ptrkey = strings; *ptrkey; ptrkey++) {
		if (*ptrkey == ',')
			count++;
	}

	sortable_keys = alloca(count * sizeof(struct sortable_keys));

	memset(sortable_keys, 0, count * sizeof(struct sortable_keys));

	/* Parse each into a struct */
	count2 = 0;
	while ((ptrkey = strsep(&strings, ","))) {
		ptrvalue = strchr(ptrkey, ':');
		if (!ptrvalue) {
			count--;
			continue;
		}
		*ptrvalue++ = '\0';
		sortable_keys[count2].key = ptrkey;
		sscanf(ptrvalue, "%f", &sortable_keys[count2].value);
		count2++;
	}

	/* Sort the structs */
	qsort(sortable_keys, count, sizeof(struct sortable_keys), sort_subroutine);

	for (count2 = 0; count2 < count; count2++) {
		int blen = strlen(buffer);
		if (element_count++) {
			strncat(buffer + blen, ",", buflen - blen - 1);
			blen++;
		}
		strncat(buffer + blen, sortable_keys[count2].key, buflen - blen - 1);
	}

	return 0;
}

static int cut_internal(struct ast_channel *chan, char *data, struct ast_str **buf, ssize_t buflen)
{
	char *parse;
	size_t delim_consumed;
	AST_DECLARE_APP_ARGS(args,
		AST_APP_ARG(varname);
		AST_APP_ARG(delimiter);
		AST_APP_ARG(field);
	);
	struct ast_str *str = ast_str_create(16);

	parse = ast_strdupa(data);

	AST_STANDARD_APP_ARGS(args, parse);

	/* Check and parse arguments */
	if (args.argc < 3) {
		ast_free(str);
		return ERROR_NOARG;
	} else {
		char ds[2] = "";
		char *tmp = alloca(strlen(args.varname) + 4);

		if (tmp) {
			snprintf(tmp, strlen(args.varname) + 4, "${%s}", args.varname);
		} else {
			ast_free(str);
			return ERROR_NOMEM;
		}

		if (ast_get_encoded_char(args.delimiter, ds, &delim_consumed))
			ast_copy_string(ds, "-", sizeof(ds));

		ast_str_substitute_variables(&str, 0, chan, tmp);

		if (ast_str_strlen(str)) {
			int curfieldnum = 1;
			char *tmp2 = ast_str_buffer(str);
			int firstfield = 1;
			while (tmp2 != NULL && args.field != NULL) {
				char *nextgroup = strsep(&(args.field), "&");
				int num1 = 0, num2 = INT_MAX;
				char trashchar;

				if (sscanf(nextgroup, "%d-%d", &num1, &num2) == 2) {
					/* range with both start and end */
				} else if (sscanf(nextgroup, "-%d", &num2) == 1) {
					/* range with end */
					num1 = 0;
				} else if ((sscanf(nextgroup, "%d%c", &num1, &trashchar) == 2) && (trashchar == '-')) {
					/* range with start */
					num2 = INT_MAX;
				} else if (sscanf(nextgroup, "%d", &num1) == 1) {
					/* single number */
					num2 = num1;
				} else {
					ast_free(str);
					return ERROR_USAGE;
				}

				/* Get to start, if any */
				if (num1 > 0) {
					while (tmp2 != NULL && curfieldnum < num1) {
						tmp2 = strchr(tmp2 + 1, ds[0]);
						curfieldnum++;
					}
				}

				/* Most frequent problem is the expectation of reordering fields */
				if ((num1 > 0) && (curfieldnum > num1))
					ast_log(LOG_WARNING, "We're already past the field you wanted?\n");

				/* Output fields until we either run out of fields or num2 is reached */
				while (tmp2 != NULL && curfieldnum <= num2) {
					char *tmp3 = strsep(&tmp2, ds);
					ast_str_append(buf, buflen, "%s%s", firstfield ? "" : ds, tmp3);
					firstfield = 0;
					curfieldnum++;
				}
			}
		}
	}
	ast_free(str);
	return 0;
}

static int acf_sort_exec(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t len)
{
	int ret = -1;

	switch (sort_internal(chan, data, buf, len)) {
	case ERROR_NOARG:
		ast_log(LOG_ERROR, "SORT() requires an argument\n");
		break;
	case ERROR_NOMEM:
		ast_log(LOG_ERROR, "Out of memory\n");
		break;
	case 0:
		ret = 0;
		break;
	default:
		ast_log(LOG_ERROR, "Unknown internal error\n");
	}

	return ret;
}

static int acf_cut_exec(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t len)
{
	int ret = -1;
	struct ast_str *str = ast_str_create(16);

	switch (cut_internal(chan, data, &str, len)) {
	case ERROR_NOARG:
		ast_log(LOG_ERROR, "Syntax: CUT(<varname>,<char-delim>,<range-spec>) - missing argument!\n");
		break;
	case ERROR_NOMEM:
		ast_log(LOG_ERROR, "Out of memory\n");
		break;
	case ERROR_USAGE:
		ast_log(LOG_ERROR, "Usage: CUT(<varname>,<char-delim>,<range-spec>)\n");
		break;
	case 0:
		ret = 0;
		ast_copy_string(buf, ast_str_buffer(str), len);
		break;
	default:
		ast_log(LOG_ERROR, "Unknown internal error\n");
	}
	ast_free(str);
	return ret;
}

static int acf_cut_exec2(struct ast_channel *chan, const char *cmd, char *data, struct ast_str **buf, ssize_t len)
{
	int ret = -1;

	switch (cut_internal(chan, data, buf, len)) {
	case ERROR_NOARG:
		ast_log(LOG_ERROR, "Syntax: CUT(<varname>,<char-delim>,<range-spec>) - missing argument!\n");
		break;
	case ERROR_NOMEM:
		ast_log(LOG_ERROR, "Out of memory\n");
		break;
	case ERROR_USAGE:
		ast_log(LOG_ERROR, "Usage: CUT(<varname>,<char-delim>,<range-spec>)\n");
		break;
	case 0:
		ret = 0;
		break;
	default:
		ast_log(LOG_ERROR, "Unknown internal error\n");
	}

	return ret;
}

static struct ast_custom_function acf_sort = {
	.name = "SORT",
	.read = acf_sort_exec,
};

static struct ast_custom_function acf_cut = {
	.name = "CUT",
	.read = acf_cut_exec,
	.read2 = acf_cut_exec2,
};

static int unload_module(void)
{
	int res = 0;

	res |= ast_custom_function_unregister(&acf_cut);
	res |= ast_custom_function_unregister(&acf_sort);

	return res;
}

static int load_module(void)
{
	int res = 0;

	res |= ast_custom_function_register(&acf_cut);
	res |= ast_custom_function_register(&acf_sort);

	return res;
}

AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Cut out information from a string");