/* Copyright (C) 2006-2007 G.P. Halkes
   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License version 3, as
   published by the Free Software Foundation.

   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, see <http://www.gnu.org/licenses/>.
*/

#include <ctype.h>

#include "definitions.h"
#include "optionMacros.h"

#define VERSION_STRING "1.3"

typedef struct {
	const char *name;
	const char *description;
	const char *sequence;
} Color;

Color colors[] = {
	{ "black", N_("Black"), "\033[0;30m" },
	{ "red", N_("Red"), "\033[0;31m" },
	{ "green", N_("Green"), "\033[0;32m" },
	{ "brown", N_("Brown"), "\033[0;33m" },
	{ "blue", N_("Blue"), "\033[0;34m" },
	{ "magenta", N_("Magenta"), "\033[0;35m" },
	{ "cyan", N_("Cyan"), "\033[0;36m" },
	{ "gray", N_("Gray"), "\033[0;37m" },
	{ "dgray", N_("Dark gray"), "\033[0;30;1m" },
	{ "bred", N_("Bright red"), "\033[0;31;1m" },
	{ "bgreen", N_("Bright green"), "\033[0;32;1m" },
	{ "yellow", N_("Yellow"), "\033[0;33;1m" },
	{ "bblue", N_("Bright blue"), "\033[0;34;1m" },
	{ "bmagenta", N_("Bright magenta"), "\033[0;35;1m" },
	{ "bcyan", N_("Bright cyan"), "\033[0;36;1m" },
	{ "white", N_("White"), "\033[0;37;1m" },
	{ NULL, NULL, NULL}
};

/** Compare two strings, ignoring case.
	@param a The first string to compare.
	@param b The first string to compare.
	@retval an integer smaller, equal, or larger than zero to indicate that @a a
		sorts before, the same, or after @a b.
*/
int strCaseCmp(const char *a, const char *b) {
	int ca, cb;
	while ((ca = tolower(*a++)) == (cb = tolower(*b++)) && ca != 0) {}

	return ca == cb ? 0 : (ca < cb ? -1 : 1);
}

/** Convert a string from the input format to an internally usable string.
	@param string A @a Token with the string to be converted.
	@param descr A description of the string to be included in error messages.
	@return The length of the resulting string.

	The use of this function processes escape characters. The converted
	characters are written in the original string.
*/
static size_t parseEscapes(char *string, const char *descr) {
	size_t maxReadPosition = strlen(string);
	size_t readPosition = 0, writePosition = 0;
	size_t i;
	
	while(readPosition < maxReadPosition) {
		if (string[readPosition] == '\\') {
			readPosition++;

			if (readPosition == maxReadPosition) {
				fatal(_("Single backslash at end of %s argument\n"), descr);
			}
			switch(string[readPosition++]) {
				case 'n':
					string[writePosition++] = '\n';
					break;
				case 'r':
					string[writePosition++] = '\r';
					break;
				case '\'':
					string[writePosition++] = '\'';
					break;
				case '\\':
					string[writePosition++] = '\\';
					break;
				case 't':
					string[writePosition++] = '\t';
					break;
				case 'b':
					string[writePosition++] = '\b';
					break;
				case 'f':
					string[writePosition++] = '\f';
					break;
				case 'a':
					string[writePosition++] = '\a';
					break;
				case 'v':
					string[writePosition++] = '\v';
					break;
				case '?':
					string[writePosition++] = '\?';
					break;
				case '"':
					string[writePosition++] = '"';
					break;
				case 'x': {
					/* Hexadecimal escapes */
					int value = 0;
					/* Read at most two characters, or as many as are valid. */
					for (i = 0; i < 2 && (readPosition + i) < maxReadPosition && isxdigit(string[readPosition + i]); i++) {
						value <<= 4;
						if (isdigit(string[readPosition + i]))
							value += (int) (string[readPosition + i] - '0');
						else
							value += (int) (tolower(string[readPosition + i]) - 'a') + 10;
					}
					readPosition += i;
					
					if (i == 0)
						fatal(_("Invalid hexadecimal escape sequence in %s argument\n"), descr);

					string[writePosition++] = (char) value;
					break;
				}
				case '0':
				case '1':
				case '2': {
					/* Octal escapes */
					int value = (int)(string[readPosition - 1] - '0');
					for (i = 0; i < 2 && readPosition + i < maxReadPosition && string[readPosition + i] >= '0' && string[readPosition + i] <= '7'; i++)
						value = value * 8 + (int)(string[readPosition + i] - '0');

					readPosition += i;
					
					string[writePosition++] = (char) value;
					break;
				}
				default:
					string[writePosition++] = string[readPosition];
					break;
			}
		} else {
			string[writePosition++] = string[readPosition++];
		}
	}
	/* Terminate string. */
	string[writePosition] = 0;
	return writePosition;
}

static void noDefaultMarkers(void) {
	/* Note: then lenghts are 0 by default. */
	if (option.addStart == NULL)
		option.addStart = "";
	if (option.addStop == NULL)
		option.addStop = "";
	if (option.delStart == NULL)
		option.delStart = "";
	if (option.delStop == NULL)
		option.delStop = "";
}

const char *descriptions[] = {
N_("-d <delim>, --delimiters=<delim>       Specifiy delimiters\n"),
N_("-W <ws>, --white-space=<ws>            Specify whitespace characters\n"),
N_("-h, --help                             Print this help message\n"),
N_("-v, --version                          Print version and copyright information\n"),
N_("-1, --no-deleted                       Do not print deleted words\n"),
N_("-2, --no-inserted                      Do not print inserted words\n"),
N_("-3, --no-common                        Do not print common words\n"),
N_("-i, --ignore-case                      Ignore differences in case\n"),
N_("-s, --statistics                       Print statistics when done\n"),
N_("-p, --printer                          Use overstriking and bold text\n"),
N_("-l, --less-mode                        As -p but also overstrike whitespace\n"),
N_("-w <string>, --start-delete=<string>   String to mark begin of deleted text\n"),
N_("-x <string>, --stop-delete=<string>    String to mark end of deleted text\n"),
N_("-y <string>, --start-insert=<string>   String to mark begin of inserted text\n"),
N_("-z <string>, --stop-insert=<string>    String to mark end of inserted text\n"),
N_("-D <option>, --diff-option=<option>    Add <option> to the diff command-line\n"),
N_("-c[<spec>], --color[=<spec>]           Color mode\n"),
N_("-L[<width>], --line-numbers[<width>]   Prepend line numbers\n"),
N_("-C<num>, --context=<num>               Show <num> lines of context\n"),
NULL};

PARSE_FUNCTION(parseCmdLine)
	bool whitespaceSet = false;

	int noOptionCount = 0;
	/* Initialise options to correct values */
	memset(&option, 0, sizeof(option));
	option.printDeleted = option.printAdded = option.printCommon = true;
	SET_BIT(option.whitespace, ' ');
	SET_BIT(option.whitespace, '\t');
	SET_BIT(option.whitespace, '\n');
	SET_BIT(option.whitespace, '\r');
	SET_BIT(option.whitespace, '\f');
	SET_BIT(option.whitespace, '\v');
	option.needStartStop = true;
#ifdef NO_MINUS_A
	option.transliterate = true;
#endif

	OPTIONS
		OPTION('d', "delimiters", REQUIRED_ARG)
			size_t i, length = parseEscapes(optarg, "delimiters");
			for (i = 0; i < length; i++) {
				SET_BIT(option.delimiters, optarg[i]);
				if (whitespaceSet && TEST_BIT(option.whitespace, optarg[i]))
					fatal(_("Whitespace and delimiter sets overlap\n"));
				else
					RESET_BIT(option.whitespace, optarg[i]);
			}
		END_OPTION
		OPTION('W', "white-space", REQUIRED_ARG)
			whitespaceSet = true;
			size_t i, length = parseEscapes(optarg, "whitespace");
			memset(option.whitespace, 0, BITMASK_SIZE);
			for (i = 0; i < length; i++) {
				SET_BIT(option.whitespace, optarg[i]);
				if (TEST_BIT(option.delimiters, optarg[i]))
					fatal(_("Whitespace and delimiter sets overlap\n"));
			}
			for (i = 0; i < BITMASK_SIZE; i++) {
				if (option.whitespace[i] != (char) 0xff) {
					int j;
					for (j = 0; j < 7; j++)
						if (!(option.whitespace[i] & (1 << j)))
							break;
					option.whitespaceDelimiter = (i << 3) + j;
					break;
				}
			}
			if (i == BITMASK_SIZE)
				fatal(_("All characters were designated as whitespace\n"));
		END_OPTION

		OPTION('h', "help", NO_ARG)
				int i = 0;
				printf(_("Usage: dwdiff [OPTIONS] <OLD FILE> <NEW FILE>\n"));
				while (descriptions[i] != NULL)
					fputs(_(descriptions[i++]), stdout);
				exit(EXIT_SUCCESS);
		END_OPTION
		OPTION('v', "version", NO_ARG)
			fputs("dwdiff " VERSION_STRING "\n", stdout);
			fputs(
				/* TRANSLATORS:
				   - If the (C) symbol (that is the c in a circle) is not available,
					 leave as it as is. (Unicode code point 0x00A9)
				   - G.P. Halkes is name and should be left as is. */
				_("Copyright (C) 2006-2007 G.P. Halkes\nLicensed under the GNU General Public License version 3\n"), stdout);
			exit(EXIT_SUCCESS);
		END_OPTION
		OPTION('1', "no-deleted", NO_ARG)
			option.printDeleted = false;
			if (!option.printAdded)
				option.needMarkers = true;
			if (!option.printCommon || !option.printAdded)
				option.needStartStop = false;
		END_OPTION
		OPTION('2', "no-inserted", NO_ARG)
			option.printAdded = false;
			if (!option.printDeleted)
				option.needMarkers = true;
			if (!option.printCommon || !option.printDeleted)
				option.needStartStop = false;
		END_OPTION
		OPTION('3', "no-common", NO_ARG)
			option.printCommon = false;
			option.needMarkers = true;
		END_OPTION
		OPTION('i', "ignore-case", NO_ARG)
#ifdef NO_MINUS_I
			fatal(_("The %.*s option is not supported by the underlying diff program.\n"), (int) optlength, CURRENT_OPTION);
#else
			option.ignoreCase = true;
#endif
		END_OPTION
		OPTION('s', "statistics", NO_ARG)
			option.statistics = true;
		END_OPTION
		OPTION('a', "autopager", NO_ARG)
			fatal(_("Option %.*s is not supported\n"), (int) optlength, CURRENT_OPTION);
		END_OPTION
		OPTION('p', "printer", NO_ARG)
			option.printer = true;
			noDefaultMarkers();
		END_OPTION
		OPTION('l', "less", NO_ARG)
			option.less = true;
			noDefaultMarkers();
		END_OPTION
		OPTION('t', "terminal", NO_ARG)
			fatal(_("Option %.*s is not supported\n"), (int) optlength, CURRENT_OPTION);
		END_OPTION
		OPTION('w', "start-delete", REQUIRED_ARG)
			option.delStartLen = parseEscapes(optarg, "start-delete");
			option.delStart = optarg;
		END_OPTION
		OPTION('x', "stop-delete", REQUIRED_ARG)
			option.delStopLen = parseEscapes(optarg, "stop-delete");
			option.delStop = optarg;
		END_OPTION
		OPTION('y', "start-insert", REQUIRED_ARG)
			option.addStartLen = parseEscapes(optarg, "start-insert");
			option.addStart = optarg;
		END_OPTION
		OPTION('z', "stop-insert", REQUIRED_ARG)
			option.addStopLen = parseEscapes(optarg, "stop-insert");
			option.addStop = optarg;
		END_OPTION
		OPTION('n', "avoid-wraps", NO_ARG)
			fatal(_("Option %.*s is not supported\n"), (int) optlength, CURRENT_OPTION);
		END_OPTION
		SINGLE_DASH
			switch (noOptionCount++) {
				case 0:
					option.oldFile.input = stdin;
					break;
				case 1:
					if (option.oldFile.name == NULL)
						fatal(_("Can't read both files from standard input\n"));
					option.newFile.input = stdin;
					break;
				default:
					fatal(_("Too many files to compare\n"));
			}
		END_OPTION
		DOUBLE_DASH
			/* Read all further options as file names, and stop processing*/
			for (optind++; optind < argc; optind++) {
				switch (noOptionCount++) {
					case 0:
						option.oldFile.name = CURRENT_OPTION;
						break;
					case 1:
						option.newFile.name = CURRENT_OPTION;
						break;
					default:
						fatal(_("Too many files to compare\n"));
				}
			}
			break;
		END_OPTION
		OPTION('D', "diff-option", REQUIRED_ARG)
			option.diffOption = optarg;
		END_OPTION
		OPTION('c', "color", OPTIONAL_ARG)
			option.colorMode = true;
			if (optarg != NULL) {
				char *comma;
				int i;

				if (strCaseCmp(optarg, "list") == 0) {
					fputs(
						/* TRANSLATORS:
						   "Name" and "Description" are table headings for the color name list.
						   Make sure you keep the alignment of the headings over the text. */
						_("Name            Description\n"), stdout);
					fputs("--              --\n", stdout);
					for (i = 0; colors[i].name != NULL; i++)
						printf("%-15s %s\n", colors[i].name, _(colors[i].description));

					exit(EXIT_SUCCESS);
				}

				comma = strchr(optarg, ',');
				if (comma != NULL && strrchr(optarg, ',') != comma)
					fatal(_("Invalid color specification %s\n"), optarg);

				if (comma != NULL)
					*comma++ = 0;

				if (optarg[0] == 0) { /* , has already been converted to 0 */
					option.delColor = colors[9].sequence;
				} else {
					for (i = 0; colors[i].name != NULL; i++) {
						if (strCaseCmp(optarg, colors[i].name) == 0) {
							option.delColor = colors[i].sequence;
							break;
						}
					}
					if (colors[i].name == NULL)
						fatal(_("Invalid color %s\n"), optarg);
				}

				if (comma == NULL) {
					option.addColor = colors[10].sequence;
				} else {
					for (i = 0; colors[i].name != NULL; i++) {
						if (strCaseCmp(comma, colors[i].name) == 0) {
							option.addColor = colors[i].sequence;
							break;
						}
					}
					if (colors[i].name == NULL)
						fatal(_("Invalid color %s\n"), comma);
				}
			} else {
					option.delColor = colors[9].sequence;
					option.addColor = colors[10].sequence;
			}
			option.delColorLen = strlen(option.delColor);
			option.addColorLen = strlen(option.addColor);
			noDefaultMarkers();
		END_OPTION
		OPTION('L', "line-numbers", OPTIONAL_ARG)
			if (optarg != NULL)
				PARSE_INT(option.lineNumbers, 1, INT_MAX);
			else
				option.lineNumbers = DEFAULT_LINENUMBER_WIDTH;
		END_OPTION
		OPTION('C', "context", REQUIRED_ARG)
			PARSE_INT(option.contextLines, 0, INT_MAX);
			option.context = true;
			initContextBuffers();
		END_OPTION
		fatal(_("Option %.*s does not exist\n"), (int) optlength, CURRENT_OPTION);
	NO_OPTION
		switch (noOptionCount++) {
			case 0:
				option.oldFile.name = CURRENT_OPTION;
				break;
			case 1:
				option.newFile.name = CURRENT_OPTION;
				break;
			default:
				fatal(_("Too many files to compare\n"));
		}
	END_OPTIONS
	/* Check that we have something to work with. */
	if (noOptionCount != 2)
		fatal(_("Need two files to compare\n"));
	
	/* Check and set some values */
	if (option.delStart == NULL) {
		option.delStart = "[-";
		option.delStartLen = 2;
	}
	if (option.delStop == NULL) {
		option.delStop = "-]";
		option.delStopLen = 2;
	}
	if (option.addStart == NULL) {
		option.addStart = "{+";
		option.addStartLen = 2;
	}
	if (option.addStop == NULL) {
		option.addStop = "+}";
		option.addStopLen = 2;
	}

	if (!option.printCommon && !option.printAdded && !option.printDeleted)
		option.needMarkers = false;

	if ((!option.printAdded + !option.printDeleted + !option.printCommon) == 2)
		option.needStartStop = false;

#ifndef NO_MINUS_A
	/* Not needed if there is no -a option, as option.transliterate will always
	   be true then. */
	if (!TEST_BIT(option.whitespace, '\n'))
		option.transliterate = true;
#endif
END_FUNCTION