/* $Id$ */

/*
 * This file is part of OpenTTD.
 * OpenTTD 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, version 2.
 * OpenTTD 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 OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/** @file strgen.cpp Tool to create computer readable (stand-alone) translation files. */

#include "../stdafx.h"
#include "../core/endian_func.hpp"
#include "../string_func.h"
#include "../strings_type.h"
#include "../language.h"
#include "../misc/getoptdata.h"
#include "../table/control_codes.h"

#include <stdarg.h>
#include <exception>

#if (!defined(WIN32) && !defined(WIN64)) || defined(__CYGWIN__)
#include <unistd.h>
#include <sys/stat.h>
#endif

#if defined WIN32 || defined __WATCOMC__
#include <direct.h>
#endif /* WIN32 || __WATCOMC__ */

#ifdef __MORPHOS__
#ifdef stderr
#undef stderr
#endif
#define stderr stdout
#endif /* __MORPHOS__ */

#include "../table/strgen_tables.h"

/* Compiles a list of strings into a compiled string list */

static bool _translated;                     ///< Whether the current language is not the master language
static bool _translation;                    ///< Is the current file actually a translation or not
static const char *_file = "(unknown file)"; ///< The filename of the input, so we can refer to it in errors/warnings
static int _cur_line;                        ///< The current line we're parsing in the input file
static int _errors, _warnings, _show_todo;

static const ptrdiff_t MAX_COMMAND_PARAM_SIZE = 100; ///< Maximum size of every command block, not counting the name of the command itself
static const CmdStruct *ParseCommandString(const char **str, char *param, int *argno, int *casei);

/** Container for the different cases of a string. */
struct Case {
	int caseidx;  ///< The index of the case.
	char *string; ///< The translation of the case.
	Case *next;   ///< The next, chained, case.

	/**
	 * Create a new case.
	 * @param caseidx The index of the case.
	 * @param string  The translation of the case.
	 * @param next    The next chained case.
	 */
	Case(int caseidx, const char *string, Case *next) :
			caseidx(caseidx), string(strdup(string)), next(next)
	{
	}

	/** Free everything we allocated. */
	~Case()
	{
		free(this->string);
		delete this->next;
	}
};

/** Information about a single string. */
struct LangString {
	char *name;            ///< Name of the string.
	char *english;         ///< English text.
	char *translated;      ///< Translated text.
	uint16 hash_next;      ///< Next hash entry.
	uint16 index;          ///< The index in the language file.
	int line;              ///< Line of string in source-file.
	Case *translated_case; ///< Cases of the translation.

	/**
	 * Create a new string.
	 * @param name    The name of the string.
	 * @param english The english "translation" of the string.
	 * @param index   The index in the string table.
	 * @param line    The line this string was found on.
	 */
	LangString(const char *name, const char *english, int index, int line) :
			name(strdup(name)), english(strdup(english)), translated(NULL),
			hash_next(0), index(index), line(line), translated_case(NULL)
	{
	}

	/** Free everything we allocated. */
	~LangString()
	{
		free(this->name);
		free(this->english);
		free(this->translated);
		delete this->translated_case;
	}
};

/** Information about the currently known strings. */
struct StringData {
	static const uint STRINGS_IN_TAB = 2048;

	LangString **strings; ///< Array of all known strings.
	uint16 *hash_heads;   ///< Hash table for the strings.
	size_t tabs;          ///< The number of 'tabs' of strings.
	size_t max_strings;   ///< The maxmimum number of strings.
	int next_string_id;   ///< The next string ID to allocate.

	/**
	 * Create a new string data container.
	 * @param max_strings The maximum number of strings.
	 */
	StringData(size_t tabs = 32) : tabs(tabs), max_strings(tabs * STRINGS_IN_TAB)
	{
		this->strings = CallocT<LangString *>(max_strings);
		this->hash_heads = CallocT<uint16>(max_strings);
		this->next_string_id = 0;
	}

	/** Free everything we allocated. */
	~StringData()
	{
		for (size_t i = 0; i < this->max_strings; i++) delete this->strings[i];
		free(this->strings);
		free(this->hash_heads);
	}

	/**
	 * Create a hash of the string for finding them back quickly.
	 * @param s The string to hash.
	 * @return The hashed string.
	 */
	uint HashStr(const char *s) const
	{
		uint hash = 0;
		for (; *s != '\0'; s++) hash = ROL(hash, 3) ^ *s;
		return hash % this->max_strings;
	}

	/**
	 * Add a newly created LangString.
	 * @param s  The name of the string.
	 * @param ls The string to add.
	 */
	void Add(const char *s, LangString *ls)
	{
		uint hash = this->HashStr(s);
		ls->hash_next = this->hash_heads[hash];
		/* Off-by-one for hash find. */
		this->hash_heads[hash] = ls->index + 1;
		this->strings[ls->index] = ls;
	}

	/**
	 * Find a LangString based on the string name.
	 * @param s The string name to search on.
	 * @return The LangString or NULL if it is not known.
	 */
	LangString *Find(const char *s)
	{
		int idx = this->hash_heads[this->HashStr(s)];

		while (--idx >= 0) {
			LangString *ls = this->strings[idx];

			if (strcmp(ls->name, s) == 0) return ls;
			idx = ls->hash_next;
		}
		return NULL;
	}

	/**
	 * Create a compound hash.
	 * @param hash The hash to add the string hash to.
	 * @param s    The string hash.
	 * @return The new hash.
	 */
	uint VersionHashStr(uint hash, const char *s) const
	{
		for (; *s != '\0'; s++) {
			hash = ROL(hash, 3) ^ *s;
			hash = (hash & 1 ? hash >> 1 ^ 0xDEADBEEF : hash >> 1);
		}
		return hash;
	}

	/**
	 * Make a hash of the file to get a unique "version number"
	 * @return The version number.
	 */
	uint Version() const
	{
		uint hash = 0;

		for (size_t i = 0; i < this->max_strings; i++) {
			const LangString *ls = this->strings[i];

			if (ls != NULL) {
				const CmdStruct *cs;
				const char *s;
				char buf[MAX_COMMAND_PARAM_SIZE];
				int argno;
				int casei;

				s = ls->name;
				hash ^= i * 0x717239;
				hash = (hash & 1 ? hash >> 1 ^ 0xDEADBEEF : hash >> 1);
				hash = this->VersionHashStr(hash, s + 1);

				s = ls->english;
				while ((cs = ParseCommandString(&s, buf, &argno, &casei)) != NULL) {
					if (cs->flags & C_DONTCOUNT) continue;

					hash ^= (cs - _cmd_structs) * 0x1234567;
					hash = (hash & 1 ? hash >> 1 ^ 0xF00BAA4 : hash >> 1);
				}
			}
		}

		return hash;
	}

	/**
	 * Count the number of tab elements that are in use.
	 * @param tab The tab to count the elements of.
	 */
	uint CountInUse(uint tab) const
	{
		int i;
		for (i = STRINGS_IN_TAB; --i >= 0;) if (this->strings[(tab * STRINGS_IN_TAB) + i] != NULL) break;
		return i + 1;
	}
};

static LanguagePackHeader _lang; ///< Header information about a language.

static const char *_cur_ident;

struct CmdPair {
	const CmdStruct *a;
	const char *v;
};

struct ParsedCommandStruct {
	uint np;
	CmdPair pairs[32];
	const CmdStruct *cmd[32]; // ordered by param #
};

/* Used when generating some advanced commands. */
static ParsedCommandStruct _cur_pcs;
static int _cur_argidx;

#ifdef _MSC_VER
# define LINE_NUM_FMT(s) "%s (%d): warning: %s (" s ")\n"
#else
# define LINE_NUM_FMT(s) "%s:%d: " s ": %s\n"
#endif

static void CDECL strgen_warning(const char *s, ...) WARN_FORMAT(1, 2);

static void CDECL strgen_warning(const char *s, ...)
{
	char buf[1024];
	va_list va;
	va_start(va, s);
	vsnprintf(buf, lengthof(buf), s, va);
	va_end(va);
	fprintf(stderr, LINE_NUM_FMT("warning"), _file, _cur_line, buf);
	_warnings++;
}

static void CDECL strgen_error(const char *s, ...) WARN_FORMAT(1, 2);

static void CDECL strgen_error(const char *s, ...)
{
	char buf[1024];
	va_list va;
	va_start(va, s);
	vsnprintf(buf, lengthof(buf), s, va);
	va_end(va);
	fprintf(stderr, LINE_NUM_FMT("error"), _file, _cur_line, buf);
	_errors++;
}

void NORETURN CDECL error(const char *s, ...)
{
	char buf[1024];
	va_list va;
	va_start(va, s);
	vsnprintf(buf, lengthof(buf), s, va);
	va_end(va);
	fprintf(stderr, LINE_NUM_FMT("FATAL"), _file, _cur_line, buf);
#ifdef _MSC_VER
	fprintf(stderr, LINE_NUM_FMT("warning"), _file, _cur_line, "language is not compiled");
#endif
	throw std::exception();
}

/** The buffer for writing a single string. */
struct Buffer : SmallVector<byte, 256> {
	/**
	 * Conveniance method for adding a byte.
	 * @param value The value to add.
	 */
	void AppendByte(byte value)
	{
		*this->Append() = value;
	}

	/**
	 * Add an Unicode character encoded in UTF-8 to the buffer.
	 * @param value The character to add.
	 */
	void AppendUtf8(uint32 value)
	{
		if (value < 0x80) {
			*this->Append() = value;
		} else if (value < 0x800) {
			*this->Append() = 0xC0 + GB(value,  6, 5);
			*this->Append() = 0x80 + GB(value,  0, 6);
		} else if (value < 0x10000) {
			*this->Append() = 0xE0 + GB(value, 12, 4);
			*this->Append() = 0x80 + GB(value,  6, 6);
			*this->Append() = 0x80 + GB(value,  0, 6);
		} else if (value < 0x110000) {
			*this->Append() = 0xF0 + GB(value, 18, 3);
			*this->Append() = 0x80 + GB(value, 12, 6);
			*this->Append() = 0x80 + GB(value,  6, 6);
			*this->Append() = 0x80 + GB(value,  0, 6);
		} else {
			strgen_warning("Invalid unicode value U+0x%X", value);
		}
	}
};

size_t Utf8Validate(const char *s)
{
	uint32 c;

	if (!HasBit(s[0], 7)) {
		/* 1 byte */
		return 1;
	} else if (GB(s[0], 5, 3) == 6 && IsUtf8Part(s[1])) {
		/* 2 bytes */
		c = GB(s[0], 0, 5) << 6 | GB(s[1], 0, 6);
		if (c >= 0x80) return 2;
	} else if (GB(s[0], 4, 4) == 14 && IsUtf8Part(s[1]) && IsUtf8Part(s[2])) {
		/* 3 bytes */
		c = GB(s[0], 0, 4) << 12 | GB(s[1], 0, 6) << 6 | GB(s[2], 0, 6);
		if (c >= 0x800) return 3;
	} else if (GB(s[0], 3, 5) == 30 && IsUtf8Part(s[1]) && IsUtf8Part(s[2]) && IsUtf8Part(s[3])) {
		/* 4 bytes */
		c = GB(s[0], 0, 3) << 18 | GB(s[1], 0, 6) << 12 | GB(s[2], 0, 6) << 6 | GB(s[3], 0, 6);
		if (c >= 0x10000 && c <= 0x10FFFF) return 4;
	}

	return 0;
}


static void EmitSingleChar(Buffer *buffer, char *buf, int value)
{
	if (*buf != '\0') strgen_warning("Ignoring trailing letters in command");
	buffer->AppendUtf8(value);
}


/* The plural specifier looks like
 * {NUM} {PLURAL -1 passenger passengers} then it picks either passenger/passengers depending on the count in NUM */

/* This is encoded like
 *  CommandByte <ARG#> <NUM> {Length of each string} {each string} */

bool ParseRelNum(char **buf, int *value, int *offset)
{
	const char *s = *buf;
	char *end;
	bool rel = false;

	while (*s == ' ' || *s == '\t') s++;
	if (*s == '+') {
		rel = true;
		s++;
	}
	int v = strtol(s, &end, 0);
	if (end == s) return false;
	if (rel || v < 0) {
		*value += v;
	} else {
		*value = v;
	}
	if (offset != NULL && *end == ':') {
		/* Take the Nth within */
		s = end + 1;
		*offset = strtol(s, &end, 0);
		if (end == s) return false;
	}
	*buf = end;
	return true;
}

/* Parse out the next word, or NULL */
char *ParseWord(char **buf)
{
	char *s = *buf, *r;

	while (*s == ' ' || *s == '\t') s++;
	if (*s == '\0') return NULL;

	if (*s == '"') {
		r = ++s;
		/* parse until next " or NUL */
		for (;;) {
			if (*s == '\0') break;
			if (*s == '"') {
				*s++ = '\0';
				break;
			}
			s++;
		}
	} else {
		/* proceed until whitespace or NUL */
		r = s;
		for (;;) {
			if (*s == '\0') break;
			if (*s == ' ' || *s == '\t') {
				*s++ = '\0';
				break;
			}
			s++;
		}
	}
	*buf = s;
	return r;
}

/* Forward declaration */
static int TranslateArgumentIdx(int arg, int offset = 0);

static void EmitWordList(Buffer *buffer, const char * const *words, uint nw)
{
	buffer->AppendByte(nw);
	for (uint i = 0; i < nw; i++) buffer->AppendByte(strlen(words[i]) + 1);
	for (uint i = 0; i < nw; i++) {
		for (uint j = 0; words[i][j] != '\0'; j++) buffer->AppendByte(words[i][j]);
		buffer->AppendByte(0);
	}
}

static void EmitPlural(Buffer *buffer, char *buf, int value)
{
	int argidx = _cur_argidx;
	int offset = 0;
	const char *words[5];
	int nw = 0;

	/* Parse out the number, if one exists. Otherwise default to prev arg. */
	if (!ParseRelNum(&buf, &argidx, &offset)) argidx--;

	/* Parse each string */
	for (nw = 0; nw < 5; nw++) {
		words[nw] = ParseWord(&buf);
		if (words[nw] == NULL) break;
	}

	if (nw == 0) {
		error("%s: No plural words", _cur_ident);
	}

	if (_plural_forms[_lang.plural_form].plural_count != nw) {
		if (_translated) {
			error("%s: Invalid number of plural forms. Expecting %d, found %d.", _cur_ident,
				_plural_forms[_lang.plural_form].plural_count, nw);
		} else {
			if ((_show_todo & 2) != 0) strgen_warning("'%s' is untranslated. Tweaking english string to allow compilation for plural forms", _cur_ident);
			if (nw > _plural_forms[_lang.plural_form].plural_count) {
				nw = _plural_forms[_lang.plural_form].plural_count;
			} else {
				for (; nw < _plural_forms[_lang.plural_form].plural_count; nw++) {
					words[nw] = words[nw - 1];
				}
			}
		}
	}

	buffer->AppendUtf8(SCC_PLURAL_LIST);
	buffer->AppendByte(_lang.plural_form);
	buffer->AppendByte(TranslateArgumentIdx(argidx, offset));
	EmitWordList(buffer, words, nw);
}


static void EmitGender(Buffer *buffer, char *buf, int value)
{
	int argidx = _cur_argidx;
	int offset = 0;
	uint nw;

	if (buf[0] == '=') {
		buf++;

		/* This is a {G=DER} command */
		nw = _lang.GetGenderIndex(buf);
		if (nw >= MAX_NUM_GENDERS) error("G argument '%s' invalid", buf);

		/* now nw contains the gender index */
		buffer->AppendUtf8(SCC_GENDER_INDEX);
		buffer->AppendByte(nw);
	} else {
		const char *words[MAX_NUM_GENDERS];

		/* This is a {G 0 foo bar two} command.
		 * If no relative number exists, default to +0 */
		if (!ParseRelNum(&buf, &argidx, &offset)) {}

		const CmdStruct *cmd = _cur_pcs.cmd[argidx];
		if (cmd == NULL || (cmd->flags & C_GENDER) == 0) {
			error("Command '%s' can't have a gender", cmd == NULL ? "<empty>" : cmd->cmd);
		}

		for (nw = 0; nw < MAX_NUM_GENDERS; nw++) {
			words[nw] = ParseWord(&buf);
			if (words[nw] == NULL) break;
		}
		if (nw != _lang.num_genders) error("Bad # of arguments for gender command");

		assert(IsInsideBS(cmd->value, SCC_CONTROL_START, UINT8_MAX));
		buffer->AppendUtf8(SCC_GENDER_LIST);
		buffer->AppendByte(TranslateArgumentIdx(argidx, offset));
		EmitWordList(buffer, words, nw);
	}
}

static const CmdStruct *FindCmd(const char *s, int len)
{
	for (const CmdStruct *cs = _cmd_structs; cs != endof(_cmd_structs); cs++) {
		if (strncmp(cs->cmd, s, len) == 0 && cs->cmd[len] == '\0') return cs;
	}
	return NULL;
}

static uint ResolveCaseName(const char *str, uint len)
{
	/* First get a clean copy of only the case name, then resolve it. */
	char case_str[CASE_GENDER_LEN];
	len = min(lengthof(case_str) - 1, len);
	memcpy(case_str, str, len);
	case_str[len] = '\0';

	uint8 case_idx = _lang.GetCaseIndex(case_str);
	if (case_idx >= MAX_NUM_CASES) error("Invalid case-name '%s'", case_str);
	return case_idx + 1;
}


/* returns NULL on eof
 * else returns command struct */
static const CmdStruct *ParseCommandString(const char **str, char *param, int *argno, int *casei)
{
	const char *s = *str, *start;
	char c;

	*argno = -1;
	*casei = -1;

	/* Scan to the next command, exit if there's no next command. */
	for (; *s != '{'; s++) {
		if (*s == '\0') return NULL;
	}
	s++; // Skip past the {

	if (*s >= '0' && *s <= '9') {
		char *end;

		*argno = strtoul(s, &end, 0);
		if (*end != ':') error("missing arg #");
		s = end + 1;
	}

	/* parse command name */
	start = s;
	do {
		c = *s++;
	} while (c != '}' && c != ' ' && c != '=' && c != '.' && c != 0);

	const CmdStruct *cmd = FindCmd(start, s - start - 1);
	if (cmd == NULL) {
		strgen_error("Undefined command '%.*s'", (int)(s - start - 1), start);
		return NULL;
	}

	if (c == '.') {
		const char *casep = s;

		if (!(cmd->flags & C_CASE)) {
			error("Command '%s' can't have a case", cmd->cmd);
		}

		do {
			c = *s++;
		} while (c != '}' && c != ' ' && c != '\0');
		*casei = ResolveCaseName(casep, s - casep - 1);
	}

	if (c == '\0') {
		strgen_error("Missing } from command '%s'", start);
		return NULL;
	}


	if (c != '}') {
		if (c == '=') s--;
		/* copy params */
		start = s;
		for (;;) {
			c = *s++;
			if (c == '}') break;
			if (c == '\0') {
				strgen_error("Missing } from command '%s'", start);
				return NULL;
			}
			if (s - start == MAX_COMMAND_PARAM_SIZE) error("param command too long");
			*param++ = c;
		}
	}
	*param = '\0';

	*str = s;

	return cmd;
}

/** Helper for reading strings. */
struct StringReader {
	StringData &data; ///< The data to fill during reading.
	const char *file; ///< The file we are reading.
	bool master;      ///< Are we reading the master file?
	bool translation; ///< Are we reading a translation, implies !master. However, the base translation will have this false.

	/**
	 * Prepare reading.
	 * @param data        The data to fill during reading.
	 * @param file        The file we are reading.
	 * @param master      Are we reading the master file?
	 * @param translation Are we reading a translation?
	 */
	StringReader(StringData &data, const char *file, bool master, bool translation) :
			data(data), file(strdup(file)), master(master), translation(translation)
	{
	}

	/** Make sure the right reader gets freed. */
	virtual ~StringReader()
	{
		free(file);
	}

	/**
	 * Read a single line from the source of strings.
	 * @param buffer The buffer to read the data in to.
	 * @param size   The size of the buffer.
	 * @return The buffer, or NULL if at the end of the file.
	 */
	virtual char *ReadLine(char *buffer, size_t size) = 0;

	/**
	 * Handle the pragma of the file.
	 * @param str    The pragma string to parse.
	 */
	virtual void HandlePragma(char *str) = 0;

	/**
	 * Handle reading a single string.
	 * @param str The string to handle.
	 */
	void HandleString(char *str);

	/**
	 * Start parsing the file.
	 */
	virtual void ParseFile();
};

/** A reader that simply reads using fopen. */
struct FileStringReader : StringReader {
	FILE *fh; ///< The file we are reading.

	/**
	 * Create the reader.
	 * @param data        The data to fill during reading.
	 * @param file        The file we are reading.
	 * @param master      Are we reading the master file?
	 * @param translation Are we reading a translation?
	 */
	FileStringReader(StringData &data, const char *file, bool master, bool translation) :
			StringReader(data, file, master, translation)
	{
		this->fh = fopen(file, "rb");
		if (this->fh == NULL) error("Could not open %s", file);
	}

	/** Free/close the file. */
	virtual ~FileStringReader()
	{
		fclose(this->fh);
	}

	/* virtual */ char *ReadLine(char *buffer, size_t size)
	{
		return fgets(buffer, size, this->fh);
	}

	/* virtual */ void HandlePragma(char *str);

	/* virtual */ void ParseFile()
	{
		this->StringReader::ParseFile();

		if (StrEmpty(_lang.name) || StrEmpty(_lang.own_name) || StrEmpty(_lang.isocode)) {
			error("Language must include ##name, ##ownname and ##isocode");
		}
	}
};

void FileStringReader::HandlePragma(char *str)
{
	if (!memcmp(str, "id ", 3)) {
		this->data.next_string_id = strtoul(str + 3, NULL, 0);
	} else if (!memcmp(str, "name ", 5)) {
		strecpy(_lang.name, str + 5, lastof(_lang.name));
	} else if (!memcmp(str, "ownname ", 8)) {
		strecpy(_lang.own_name, str + 8, lastof(_lang.own_name));
	} else if (!memcmp(str, "isocode ", 8)) {
		strecpy(_lang.isocode, str + 8, lastof(_lang.isocode));
	} else if (!memcmp(str, "plural ", 7)) {
		_lang.plural_form = atoi(str + 7);
		if (_lang.plural_form >= lengthof(_plural_forms)) {
			error("Invalid pluralform %d", _lang.plural_form);
		}
	} else if (!memcmp(str, "textdir ", 8)) {
		if (!memcmp(str + 8, "ltr", 3)) {
			_lang.text_dir = TD_LTR;
		} else if (!memcmp(str + 8, "rtl", 3)) {
			_lang.text_dir = TD_RTL;
		} else {
			error("Invalid textdir %s", str + 8);
		}
	} else if (!memcmp(str, "digitsep ", 9)) {
		str += 9;
		strecpy(_lang.digit_group_separator, strcmp(str, "{NBSP}") == 0 ? NBSP : str, lastof(_lang.digit_group_separator));
	} else if (!memcmp(str, "digitsepcur ", 12)) {
		str += 12;
		strecpy(_lang.digit_group_separator_currency, strcmp(str, "{NBSP}") == 0 ? NBSP : str, lastof(_lang.digit_group_separator_currency));
	} else if (!memcmp(str, "decimalsep ", 11)) {
		str += 11;
		strecpy(_lang.digit_decimal_separator, strcmp(str, "{NBSP}") == 0 ? NBSP : str, lastof(_lang.digit_decimal_separator));
	} else if (!memcmp(str, "winlangid ", 10)) {
		const char *buf = str + 10;
		long langid = strtol(buf, NULL, 16);
		if (langid > (long)UINT16_MAX || langid < 0) {
			error("Invalid winlangid %s", buf);
		}
		_lang.winlangid = (uint16)langid;
	} else if (!memcmp(str, "grflangid ", 10)) {
		const char *buf = str + 10;
		long langid = strtol(buf, NULL, 16);
		if (langid >= 0x7F || langid < 0) {
			error("Invalid grflangid %s", buf);
		}
		_lang.newgrflangid = (uint8)langid;
	} else if (!memcmp(str, "gender ", 7)) {
		if (this->master) error("Genders are not allowed in the base translation.");
		char *buf = str + 7;

		for (;;) {
			const char *s = ParseWord(&buf);

			if (s == NULL) break;
			if (_lang.num_genders >= MAX_NUM_GENDERS) error("Too many genders, max %d", MAX_NUM_GENDERS);
			strecpy(_lang.genders[_lang.num_genders], s, lastof(_lang.genders[_lang.num_genders]));
			_lang.num_genders++;
		}
	} else if (!memcmp(str, "case ", 5)) {
		if (this->master) error("Cases are not allowed in the base translation.");
		char *buf = str + 5;

		for (;;) {
			const char *s = ParseWord(&buf);

			if (s == NULL) break;
			if (_lang.num_cases >= MAX_NUM_CASES) error("Too many cases, max %d", MAX_NUM_CASES);
			strecpy(_lang.cases[_lang.num_cases], s, lastof(_lang.cases[_lang.num_cases]));
			_lang.num_cases++;
		}
	} else {
		error("unknown pragma '%s'", str);
	}
}

static void ExtractCommandString(ParsedCommandStruct *p, const char *s, bool warnings)
{
	char param[MAX_COMMAND_PARAM_SIZE];
	int argno;
	int argidx = 0;
	int casei;

	memset(p, 0, sizeof(*p));

	for (;;) {
		/* read until next command from a. */
		const CmdStruct *ar = ParseCommandString(&s, param, &argno, &casei);

		if (ar == NULL) break;

		/* Sanity checking */
		if (argno != -1 && ar->consumes == 0) error("Non consumer param can't have a paramindex");

		if (ar->consumes) {
			if (argno != -1) argidx = argno;
			if (argidx < 0 || (uint)argidx >= lengthof(p->cmd)) error("invalid param idx %d", argidx);
			if (p->cmd[argidx] != NULL && p->cmd[argidx] != ar) error("duplicate param idx %d", argidx);

			p->cmd[argidx++] = ar;
		} else if (!(ar->flags & C_DONTCOUNT)) { // Ignore some of them
			if (p->np >= lengthof(p->pairs)) error("too many commands in string, max " PRINTF_SIZE, lengthof(p->pairs));
			p->pairs[p->np].a = ar;
			p->pairs[p->np].v = param[0] != '\0' ? strdup(param) : "";
			p->np++;
		}
	}
}


static const CmdStruct *TranslateCmdForCompare(const CmdStruct *a)
{
	if (a == NULL) return NULL;

	if (strcmp(a->cmd, "STRING1") == 0 ||
			strcmp(a->cmd, "STRING2") == 0 ||
			strcmp(a->cmd, "STRING3") == 0 ||
			strcmp(a->cmd, "STRING4") == 0 ||
			strcmp(a->cmd, "STRING5") == 0 ||
			strcmp(a->cmd, "RAW_STRING") == 0) {
		return FindCmd("STRING", 6);
	}

	return a;
}


static bool CheckCommandsMatch(char *a, char *b, const char *name)
{
	/* If we're not translating, i.e. we're compiling the base language,
	 * it is pointless to do all these checks as it'll always be correct.
	 * After all, all checks are based on the base language.
	 */
	if (!_translation) return true;

	ParsedCommandStruct templ;
	ParsedCommandStruct lang;
	bool result = true;

	ExtractCommandString(&templ, b, true);
	ExtractCommandString(&lang, a, true);

	/* For each string in templ, see if we find it in lang */
	if (templ.np != lang.np) {
		strgen_warning("%s: template string and language string have a different # of commands", name);
		result = false;
	}

	for (uint i = 0; i < templ.np; i++) {
		/* see if we find it in lang, and zero it out */
		bool found = false;
		for (uint j = 0; j < lang.np; j++) {
			if (templ.pairs[i].a == lang.pairs[j].a &&
					strcmp(templ.pairs[i].v, lang.pairs[j].v) == 0) {
				/* it was found in both. zero it out from lang so we don't find it again */
				lang.pairs[j].a = NULL;
				found = true;
				break;
			}
		}

		if (!found) {
			strgen_warning("%s: command '%s' exists in template file but not in language file", name, templ.pairs[i].a->cmd);
			result = false;
		}
	}

	/* if we reach here, all non consumer commands match up.
	 * Check if the non consumer commands match up also. */
	for (uint i = 0; i < lengthof(templ.cmd); i++) {
		if (TranslateCmdForCompare(templ.cmd[i]) != lang.cmd[i]) {
			strgen_warning("%s: Param idx #%d '%s' doesn't match with template command '%s'", name, i,
				lang.cmd[i]  == NULL ? "<empty>" : TranslateCmdForCompare(lang.cmd[i])->cmd,
				templ.cmd[i] == NULL ? "<empty>" : templ.cmd[i]->cmd);
			result = false;
		}
	}

	return result;
}

void StringReader::HandleString(char *str)
{
	if (*str == '#') {
		if (str[1] == '#' && str[2] != '#') this->HandlePragma(str + 2);
		return;
	}

	/* Ignore comments & blank lines */
	if (*str == ';' || *str == ' ' || *str == '\0') return;

	char *s = strchr(str, ':');
	if (s == NULL) {
		strgen_error("Line has no ':' delimiter");
		return;
	}

	char *t;
	/* Trim spaces.
	 * After this str points to the command name, and s points to the command contents */
	for (t = s; t > str && (t[-1] == ' ' || t[-1] == '\t'); t--) {}
	*t = 0;
	s++;

	/* Check string is valid UTF-8 */
	const char *tmp;
	for (tmp = s; *tmp != '\0';) {
		size_t len = Utf8Validate(tmp);
		if (len == 0) error("Invalid UTF-8 sequence in '%s'", s);

		WChar c;
		Utf8Decode(&c, tmp);
		if (c <= 0x001F || // ASCII control character range
				(c >= 0xE000 && c <= 0xF8FF) || // Private range
				(c >= 0xFFF0 && c <= 0xFFFF)) { // Specials range
			error("Unwanted UTF-8 character U+%04X in sequence '%s'", c, s);
		}

		tmp += len;
	}

	/* Check if the string has a case..
	 * The syntax for cases is IDENTNAME.case */
	char *casep = strchr(str, '.');
	if (casep != NULL) *casep++ = '\0';

	/* Check if this string already exists.. */
	LangString *ent = this->data.Find(str);

	if (this->master) {
		if (casep != NULL) {
			strgen_error("Cases in the base translation are not supported.");
			return;
		}

		if (ent != NULL) {
			strgen_error("String name '%s' is used multiple times", str);
			return;
		}

		if (this->data.strings[this->data.next_string_id] != NULL) {
			strgen_error("String ID 0x%X for '%s' already in use by '%s'", this->data.next_string_id, str, this->data.strings[this->data.next_string_id]->name);
			return;
		}

		/* Allocate a new LangString */
		this->data.Add(str, new LangString(str, s, this->data.next_string_id++, _cur_line));
	} else {
		if (ent == NULL) {
			strgen_warning("String name '%s' does not exist in master file", str);
			return;
		}

		if (ent->translated && casep == NULL) {
			strgen_error("String name '%s' is used multiple times", str);
			return;
		}

		/* make sure that the commands match */
		if (!CheckCommandsMatch(s, ent->english, str)) return;

		if (casep != NULL) {
			ent->translated_case = new Case(ResolveCaseName(casep, strlen(casep)), s, ent->translated_case);
		} else {
			ent->translated = strdup(s);
			/* If the string was translated, use the line from the
			 * translated language so errors in the translated file
			 * are properly referenced to. */
			ent->line = _cur_line;
		}
	}
}


static void rstrip(char *buf)
{
	int i = strlen(buf);
	while (i > 0 && (buf[i - 1] == '\r' || buf[i - 1] == '\n' || buf[i - 1] == ' ')) i--;
	buf[i] = '\0';
}

void StringReader::ParseFile()
{
	char buf[2048];

	_translation = this->master || this->translation;
	_file = this->file;

	/* For each new file we parse, reset the genders, and language codes. */
	MemSetT(&_lang, 0);
	strecpy(_lang.digit_group_separator, ",", lastof(_lang.digit_group_separator));
	strecpy(_lang.digit_group_separator_currency, ",", lastof(_lang.digit_group_separator_currency));
	strecpy(_lang.digit_decimal_separator, ".", lastof(_lang.digit_decimal_separator));

	_cur_line = 1;
	while (this->ReadLine(buf, sizeof(buf)) != NULL) {
		rstrip(buf);
		this->HandleString(buf);
		_cur_line++;
	}
}

bool CompareFiles(const char *n1, const char *n2)
{
	FILE *f2 = fopen(n2, "rb");
	if (f2 == NULL) return false;

	FILE *f1 = fopen(n1, "rb");
	if (f1 == NULL) error("can't open %s", n1);

	size_t l1, l2;
	do {
		char b1[4096];
		char b2[4096];
		l1 = fread(b1, 1, sizeof(b1), f1);
		l2 = fread(b2, 1, sizeof(b2), f2);

		if (l1 != l2 || memcmp(b1, b2, l1)) {
			fclose(f2);
			fclose(f1);
			return false;
		}
	} while (l1 != 0);

	fclose(f2);
	fclose(f1);
	return true;
}

/** Base class for writing data to disk. */
struct FileWriter {
	FILE *fh;             ///< The file handle we're writing to.
	const char *filename; ///< The file name we're writing to.

	/**
	 * Open a file to write to.
	 * @param filename The file to open.
	 */
	FileWriter(const char *filename)
	{
		this->filename = strdup(filename);
		this->fh = fopen(this->filename, "wb");

		if (this->fh == NULL) {
			error("Could not open %s", this->filename);
		}
	}

	/** Finalise the writing. */
	void Finalise()
	{
		fclose(this->fh);
		this->fh = NULL;
	}

	/** Make sure the file is closed. */
	virtual ~FileWriter()
	{
		/* If we weren't closed an exception was thrown, so remove the termporary file. */
		if (fh != NULL) {
			fclose(this->fh);
			unlink(this->filename);
		}
		free(this->filename);
	}
};

/** Base class for writing the header. */
struct HeaderWriter {
	/**
	 * Write the string ID.
	 * @param name     The name of the string.
	 * @param stringid The ID of the string.
	 */
	virtual void WriteStringID(const char *name, int stringid) = 0;

	/**
	 * Finalise writing the file.
	 * @param data The data about the string.
	 */
	virtual void Finalise(const StringData &data) = 0;

	/** Especially destroy the subclasses. */
	virtual ~HeaderWriter() {};

	/**
	 * Write the header information.
	 * @param data The data about the string.
	 */
	void WriteHeader(const StringData &data)
	{
		int last = 0;
		for (size_t i = 0; i < data.max_strings; i++) {
			if (data.strings[i] != NULL) {
				this->WriteStringID(data.strings[i]->name, i);
				last = i;
			}
		}

		this->WriteStringID("STR_LAST_STRINGID", last);
	}
};

struct HeaderFileWriter : HeaderWriter, FileWriter {
	/** The real file name we eventually want to write to. */
	const char *real_filename;
	/** The previous string ID that was printed. */
	int prev;

	/**
	 * Open a file to write to.
	 * @param filename The file to open.
	 */
	HeaderFileWriter(const char *filename) : FileWriter("tmp.xxx"),
		real_filename(strdup(filename)), prev(0)
	{
		fprintf(this->fh, "/* This file is automatically generated. Do not modify */\n\n");
		fprintf(this->fh, "#ifndef TABLE_STRINGS_H\n");
		fprintf(this->fh, "#define TABLE_STRINGS_H\n");
	}

	void WriteStringID(const char *name, int stringid)
	{
		if (prev + 1 != stringid) fprintf(this->fh, "\n");
		fprintf(this->fh, "static const StringID %s = 0x%X;\n", name, stringid);
		prev = stringid;
	}

	void Finalise(const StringData &data)
	{
		/* Find the plural form with the most amount of cases. */
		int max_plural_forms = 0;
		for (uint i = 0; i < lengthof(_plural_forms); i++) {
			max_plural_forms = max(max_plural_forms, _plural_forms[i].plural_count);
		}

		fprintf(this->fh,
			"\n"
			"static const uint LANGUAGE_PACK_VERSION     = 0x%X;\n"
			"static const uint LANGUAGE_MAX_PLURAL       = %d;\n"
			"static const uint LANGUAGE_MAX_PLURAL_FORMS = %d;\n\n",
			(uint)data.Version(), (uint)lengthof(_plural_forms), max_plural_forms
		);

		fprintf(this->fh, "#endif /* TABLE_STRINGS_H */\n");

		this->FileWriter::Finalise();

		if (CompareFiles(this->filename, this->real_filename)) {
			/* files are equal. tmp.xxx is not needed */
			unlink(this->filename);
		} else {
			/* else rename tmp.xxx into filename */
	#if defined(WIN32) || defined(WIN64)
			unlink(this->real_filename);
	#endif
			if (rename(this->filename, this->real_filename) == -1) error("rename() failed");
		}
	}
};

static int TranslateArgumentIdx(int argidx, int offset)
{
	int sum;

	if (argidx < 0 || (uint)argidx >= lengthof(_cur_pcs.cmd)) {
		error("invalid argidx %d", argidx);
	}
	const CmdStruct *cs = _cur_pcs.cmd[argidx];
	if (cs != NULL && cs->consumes <= offset) {
		error("invalid argidx offset %d:%d", argidx, offset);
	}

	if (_cur_pcs.cmd[argidx] == NULL) {
		error("no command for this argidx %d", argidx);
	}

	for (int i = sum = 0; i < argidx; i++) {
		const CmdStruct *cs = _cur_pcs.cmd[i];

		sum += (cs != NULL) ? cs->consumes : 1;
	}

	return sum + offset;
}

static void PutArgidxCommand(Buffer *buffer)
{
	buffer->AppendUtf8(SCC_ARG_INDEX);
	buffer->AppendByte(TranslateArgumentIdx(_cur_argidx));
}


static void PutCommandString(Buffer *buffer, const char *str)
{
	_cur_argidx = 0;

	while (*str != '\0') {
		/* Process characters as they are until we encounter a { */
		if (*str != '{') {
			buffer->AppendByte(*str++);
			continue;
		}

		char param[MAX_COMMAND_PARAM_SIZE];
		int argno;
		int casei;
		const CmdStruct *cs = ParseCommandString(&str, param, &argno, &casei);
		if (cs == NULL) break;

		if (casei != -1) {
			buffer->AppendUtf8(SCC_SET_CASE); // {SET_CASE}
			buffer->AppendByte(casei);
		}

		/* For params that consume values, we need to handle the argindex properly */
		if (cs->consumes > 0) {
			/* Check if we need to output a move-param command */
			if (argno != -1 && argno != _cur_argidx) {
				_cur_argidx = argno;
				PutArgidxCommand(buffer);
			}

			/* Output the one from the master string... it's always accurate. */
			cs = _cur_pcs.cmd[_cur_argidx++];
			if (cs == NULL) {
				error("%s: No argument exists at position %d", _cur_ident, _cur_argidx - 1);
			}
		}

		cs->proc(buffer, param, cs->value);
	}
}

/** Base class for all language writers. */
struct LanguageWriter {
	/**
	 * Write the header metadata. The multi-byte integers are already converted to
	 * the little endian format.
	 * @param header The header to write.
	 */
	virtual void WriteHeader(const LanguagePackHeader *header) = 0;

	/**
	 * Write a number of bytes.
	 * @param buffer The buffer to write.
	 * @param length The amount of byte to write.
	 */
	virtual void Write(const byte *buffer, size_t length) = 0;

	/**
	 * Finalise writing the file.
	 */
	virtual void Finalise() = 0;

	/** Especially destroy the subclasses. */
	virtual ~LanguageWriter() {}

	/**
	 * Write the length as a simple gamma.
	 * @param length The number to write.
	 */
	void WriteLength(uint length)
	{
		char buffer[2];
		int offs = 0;
		if (length >= 0x4000) {
			error("string too long");
		}

		if (length >= 0xC0) {
			buffer[offs++] = (length >> 8) | 0xC0;
		}
		buffer[offs++] = length & 0xFF;
		this->Write((byte*)buffer, offs);
	}

	/**
	 * Actually write the language.
	 * @param data The data about the string.
	 */
	void WriteLang(const StringData &data)
	{
		uint *in_use = AllocaM(uint, data.tabs);
		for (size_t tab = 0; tab < data.tabs; tab++) {
			uint n = data.CountInUse(tab);

			in_use[tab] = n;
			_lang.offsets[tab] = TO_LE16(n);

			for (uint j = 0; j != in_use[tab]; j++) {
				const LangString *ls = data.strings[(tab * StringData::STRINGS_IN_TAB) + j];
				if (ls != NULL && ls->translated == NULL) _lang.missing++;
			}
		}

		_lang.ident = TO_LE32(LanguagePackHeader::IDENT);
		_lang.version = TO_LE32(data.Version());
		_lang.missing = TO_LE16(_lang.missing);
		_lang.winlangid = TO_LE16(_lang.winlangid);

		this->WriteHeader(&_lang);
		Buffer buffer;

		for (size_t tab = 0; tab < data.tabs; tab++) {
			for (uint j = 0; j != in_use[tab]; j++) {
				const LangString *ls = data.strings[(tab * StringData::STRINGS_IN_TAB) + j];
				const Case *casep;
				const char *cmdp;

				/* For undefined strings, just set that it's an empty string */
				if (ls == NULL) {
					this->WriteLength(0);
					continue;
				}

				_cur_ident = ls->name;
				_cur_line = ls->line;

				/* Produce a message if a string doesn't have a translation. */
				if (_show_todo > 0 && ls->translated == NULL) {
					if ((_show_todo & 2) != 0) {
						strgen_warning("'%s' is untranslated", ls->name);
					}
					if ((_show_todo & 1) != 0) {
						const char *s = "<TODO> ";
						while (*s != '\0') buffer.AppendByte(*s++);
					}
				}

				/* Extract the strings and stuff from the english command string */
				ExtractCommandString(&_cur_pcs, ls->english, false);

				if (ls->translated_case != NULL || ls->translated != NULL) {
					casep = ls->translated_case;
					cmdp = ls->translated;
				} else {
					casep = NULL;
					cmdp = ls->english;
				}

				_translated = cmdp != ls->english;

				if (casep != NULL) {
					const Case *c;
					uint num;

					/* Need to output a case-switch.
					 * It has this format
					 * <0x9E> <NUM CASES> <CASE1> <LEN1> <STRING1> <CASE2> <LEN2> <STRING2> <CASE3> <LEN3> <STRING3> <STRINGDEFAULT>
					 * Each LEN is printed using 2 bytes in big endian order. */
					buffer.AppendUtf8(SCC_SWITCH_CASE);
					/* Count the number of cases */
					for (num = 0, c = casep; c; c = c->next) num++;
					buffer.AppendByte(num);

					/* Write each case */
					for (c = casep; c != NULL; c = c->next) {
						buffer.AppendByte(c->caseidx);
						/* Make some space for the 16-bit length */
						size_t pos = buffer.Length();
						buffer.AppendByte(0);
						buffer.AppendByte(0);
						/* Write string */
						PutCommandString(&buffer, c->string);
						buffer.AppendByte(0); // terminate with a zero
						/* Fill in the length */
						size_t size = buffer.Length() - (pos + 2);
						buffer[pos + 0] = GB(size, 8, 8);
						buffer[pos + 1] = GB(size, 0, 8);
					}
				}

				if (cmdp != NULL) PutCommandString(&buffer, cmdp);

				this->WriteLength(buffer.Length());
				this->Write(buffer.Begin(), buffer.Length());
				buffer.Clear();
			}
		}
	}
};

/** Class for writing a language to disk. */
struct LanguageFileWriter : LanguageWriter, FileWriter {
	/**
	 * Open a file to write to.
	 * @param filename The file to open.
	 */
	LanguageFileWriter(const char *filename) : FileWriter(filename)
	{
	}

	void WriteHeader(const LanguagePackHeader *header)
	{
		this->Write((const byte *)header, sizeof(*header));
	}

	void Finalise()
	{
		fputc(0, this->fh);
		this->FileWriter::Finalise();
	}

	void Write(const byte *buffer, size_t length)
	{
		if (fwrite(buffer, sizeof(*buffer), length, this->fh) != length) {
			error("Could not write to %s", this->filename);
		}
	}
};

/** Multi-OS mkdirectory function */
static inline void ottd_mkdir(const char *directory)
{
#if defined(WIN32) || defined(__WATCOMC__)
		mkdir(directory);
#else
		mkdir(directory, 0755);
#endif
}

/**
 * Create a path consisting of an already existing path, a possible
 * path seperator and the filename. The seperator is only appended if the path
 * does not already end with a seperator
 */
static inline char *mkpath(char *buf, size_t buflen, const char *path, const char *file)
{
	ttd_strlcpy(buf, path, buflen); // copy directory into buffer

	char *p = strchr(buf, '\0'); // add path seperator if necessary
	if (p[-1] != PATHSEPCHAR && (size_t)(p - buf) + 1 < buflen) *p++ = PATHSEPCHAR;
	ttd_strlcpy(p, file, buflen - (size_t)(p - buf)); // catenate filename at end of buffer
	return buf;
}

#if defined(__MINGW32__)
/**
 * On MingW, it is common that both / as \ are accepted in the
 * params. To go with those flow, we rewrite all incoming /
 * simply to \, so internally we can safely assume \.
 */
static inline char *replace_pathsep(char *s)
{
	for (char *c = s; *c != '\0'; c++) if (*c == '/') *c = '\\';
	return s;
}
#else
static inline char *replace_pathsep(char *s) { return s; }
#endif

/** Options of strgen. */
static const OptionData _opts[] = {
	  GETOPT_NOVAL(     'v',  "--version"),
	GETOPT_GENERAL('C', '\0', "-export-commands", ODF_NO_VALUE),
	GETOPT_GENERAL('L', '\0', "-export-plurals",  ODF_NO_VALUE),
	GETOPT_GENERAL('P', '\0', "-export-pragmas",  ODF_NO_VALUE),
	  GETOPT_NOVAL(     't',  "--todo"),
	  GETOPT_NOVAL(     'w',  "--warning"),
	  GETOPT_NOVAL(     'h',  "--help"),
	GETOPT_GENERAL('h', '?',  NULL,               ODF_NO_VALUE),
	  GETOPT_VALUE(     's',  "--source_dir"),
	  GETOPT_VALUE(     'd',  "--dest_dir"),
	GETOPT_END(),
};

int CDECL main(int argc, char *argv[])
{
	char pathbuf[MAX_PATH];
	const char *src_dir = ".";
	const char *dest_dir = NULL;

	GetOptData mgo(argc - 1, argv + 1, _opts);
	for (;;) {
		int i = mgo.GetOpt();
		if (i == -1) break;

		switch (i) {
			case 'v':
				puts("$Revision$");
				return 0;

			case 'C':
				printf("args\tflags\tcommand\treplacement\n");
				for (const CmdStruct *cs = _cmd_structs; cs < endof(_cmd_structs); cs++) {
					char flags;
					switch (cs->value) {
						case 0x200E: case 0x200F: // Implicit BIDI controls
						case 0x202A: case 0x202B: case 0x202C: case 0x202D: case 0x202E: // Explicit BIDI controls
						case 0xA0: // Non breaking space
						case '\n': // Newlines may be added too
						case '{':  // This special
							/* This command may be in the translation when it is not in base */
							flags = 'i';
							break;

						default:
							if (cs->proc == EmitGender) {
								flags = 'g'; // Command needs number of parameters defined by number of genders
							} else if (cs->proc == EmitPlural) {
								flags = 'p'; // Command needs number of parameters defined by plural value
							} else {
								flags = '0'; // Command needs no parameters
							}
					}
					printf("%i\t%c\t\"%s\"\t\"%s\"\n", cs->consumes, flags, cs->cmd, strstr(cs->cmd, "STRING") ? "STRING" : cs->cmd);
				}
				return 0;

			case 'L':
				printf("count\tdescription\n");
				for (const PluralForm *pf = _plural_forms; pf < endof(_plural_forms); pf++) {
					printf("%i\t\"%s\"\n", pf->plural_count, pf->description);
				}
				return 0;

			case 'P':
				printf("name\tflags\tdefault\tdescription\n");
				for (size_t i = 0; i < lengthof(_pragmas); i++) {
					printf("\"%s\"\t%s\t\"%s\"\t\"%s\"\n",
							_pragmas[i][0], _pragmas[i][1], _pragmas[i][2], _pragmas[i][3]);
				}
				return 0;

			case 't':
				_show_todo |= 1;
				break;

			case 'w':
				_show_todo |= 2;
				break;

			case 'h':
				puts(
					"strgen - $Revision$\n"
					" -v | --version    print version information and exit\n"
					" -t | --todo       replace any untranslated strings with '<TODO>'\n"
					" -w | --warning    print a warning for any untranslated strings\n"
					" -h | -? | --help  print this help message and exit\n"
					" -s | --source_dir search for english.txt in the specified directory\n"
					" -d | --dest_dir   put output file in the specified directory, create if needed\n"
					" -export-commands  export all commands and exit\n"
					" -export-plurals   export all plural forms and exit\n"
					" -export-pragmas   export all pragmas and exit\n"
					" Run without parameters and strgen will search for english.txt and parse it,\n"
					" creating strings.h. Passing an argument, strgen will translate that language\n"
					" file using english.txt as a reference and output <language>.lng."
				);
				return 0;

			case 's':
				src_dir = replace_pathsep(mgo.opt);
				break;

			case 'd':
				dest_dir = replace_pathsep(mgo.opt);
				break;

			case -2:
				fprintf(stderr, "Invalid arguments\n");
				return 0;
		}
	}

	if (dest_dir == NULL) dest_dir = src_dir; // if dest_dir is not specified, it equals src_dir

	try {
		/* strgen has two modes of operation. If no (free) arguments are passed
		 * strgen generates strings.h to the destination directory. If it is supplied
		 * with a (free) parameter the program will translate that language to destination
		 * directory. As input english.txt is parsed from the source directory */
		if (mgo.numleft == 0) {
			mkpath(pathbuf, lengthof(pathbuf), src_dir, "english.txt");

			/* parse master file */
			StringData data;
			FileStringReader master_reader(data, pathbuf, true, false);
			master_reader.ParseFile();
			if (_errors != 0) return 1;

			/* write strings.h */
			ottd_mkdir(dest_dir);
			mkpath(pathbuf, lengthof(pathbuf), dest_dir, "strings.h");

			HeaderFileWriter writer(pathbuf);
			writer.WriteHeader(data);
			writer.Finalise(data);
		} else if (mgo.numleft == 1) {
			char *r;

			mkpath(pathbuf, lengthof(pathbuf), src_dir, "english.txt");

			StringData data;
			/* parse master file and check if target file is correct */
			FileStringReader master_reader(data, pathbuf, true, false);
			master_reader.ParseFile();

			const char *translation = replace_pathsep(mgo.argv[0]);
			const char *file = strrchr(translation, PATHSEPCHAR);
			FileStringReader translation_reader(data, translation, false, file == NULL || strcmp(file + 1, "english.txt") != 0);
			translation_reader.ParseFile(); // target file
			if (_errors != 0) return 1;

			/* get the targetfile, strip any directories and append to destination path */
			r = strrchr(mgo.argv[0], PATHSEPCHAR);
			mkpath(pathbuf, lengthof(pathbuf), dest_dir, (r != NULL) ? &r[1] : mgo.argv[0]);

			/* rename the .txt (input-extension) to .lng */
			r = strrchr(pathbuf, '.');
			if (r == NULL || strcmp(r, ".txt") != 0) r = strchr(pathbuf, '\0');
			ttd_strlcpy(r, ".lng", (size_t)(r - pathbuf));

			LanguageFileWriter writer(pathbuf);
			writer.WriteLang(data);
			writer.Finalise();

			/* if showing warnings, print a summary of the language */
			if ((_show_todo & 2) != 0) {
				fprintf(stdout, "%d warnings and %d errors for %s\n", _warnings, _errors, pathbuf);
			}
		} else {
			fprintf(stderr, "Invalid arguments\n");
		}
	} catch (...) {
		return 2;
	}

	return 0;
}