/*
 * Build database of file and directory names.
 *
 * Compile this file with Visual Studio and run the produced command in
 * console with a directory name argument.  For example, command
 *
 *     updatedb C:\
 *
 * will produce the file locate.db with one file name per line such as
 *
 *     c:\Program Files/7-Zip/7-zip.chm
 *     c:\Program Files/7-Zip/7-zip.dll
 *     c:\Program Files/7-Zip/7z.dll
 *     c:\Program Files/Adobe/Reader 10.0/Reader/logsession.dll
 *     c:\Program Files/Adobe/Reader 10.0/Reader/LogTransport2.exe
 *     c:\Program Files/Windows NT/Accessories/wordpad.exe
 *     c:\Program Files/Windows NT/Accessories/write.wpc
 *
 * Be ware that this file uses wide-character API which is not compatible
 * with Linux or other major Unixes.
 *
 * Copyright (C) 1998-2019 Toni Ronkko
 * This file is part of dirent.  Dirent may be freely distributed
 * under the MIT license.  For all details and documentation, see
 * https://github.com/tronkko/dirent
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <wchar.h>
#ifdef WIN32
#	include <io.h>
#	include <fcntl.h>
#endif
#include <dirent.h>

/* File name and location of database file */
#define DB_LOCATION L"locate.db"

/* Forward-decl */
static int update_directory(const wchar_t *dirname);
static void db_open(void);
static void db_close(void);
static void db_store(const wchar_t *dirname);

/* Module local variables */
static FILE *db = NULL;

#ifdef _MSC_VER
int
wmain(int argc, wchar_t *argv[])
{
	/* Prepare for unicode output */
	_setmode(_fileno(stdout), _O_U16TEXT);

	/* Open locate.db */
	db_open();

	/* For each directory in command line */
	int i = 1;
	while (i < argc) {
		/* Scan directory for files */
		int ok = update_directory(argv[i]);
		if (!ok) {
			wprintf(L"Cannot open directory %s\n", argv[i]);
			exit(EXIT_FAILURE);
		}

		i++;
	}

	/* Use current working directory if no arguments on command line */
	if (argc == 1)
		update_directory(L".");

	db_close();
	return EXIT_SUCCESS;
}
#else
int
main(int argc, char *argv[])
{
	printf("updatedb only works on Microsoft Windows\n");
	return EXIT_SUCCESS;
}
#endif

/* Find files recursively */
static int
update_directory(const wchar_t *dirname)
{
#ifdef WIN32
	wchar_t buffer[PATH_MAX + 2];
	wchar_t *p = buffer;
	wchar_t *end = &buffer[PATH_MAX];

	/* Copy directory name to buffer */
	const wchar_t *src = dirname;
	while (p < end  &&  *src != '\0') {
		*p++ = *src++;
	}
	*p = '\0';

	/* Open directory stream */
	_WDIR *dir = _wopendir(dirname);
	if (!dir) {
		/* Cannot open directory */
		return /*failure*/ 0;
	}

	/* Print all files and directories within the directory */
	struct _wdirent *ent;
	while ((ent = _wreaddir (dir)) != NULL) {
		wchar_t *q = p;
		wchar_t c;

		/* Get final character of directory name */
		if (buffer < q)
			c = q[-1];
		else
			c = ':';

		/* Append directory separator if not already there */
		if (c != ':'  &&  c != '/'  &&  c != '\\')
			*q++ = '/';

		/* Append file name */
		src = ent->d_name;
		while (q < end  &&  *src != '\0') {
			*q++ = *src++;
		}
		*q = '\0';

		/* Decide what to do with the directory entry */
		switch (ent->d_type) {
		case DT_REG:
			/* Store file name */
			db_store(buffer);
			break;

		case DT_DIR:
			/* Scan sub-directory recursively */
			if (wcscmp(ent->d_name, L".") != 0
				&&  wcscmp(ent->d_name, L"..") != 0) {
				update_directory(buffer);
			}
			break;

		default:
			/* Do not device entries */
			/*NOP*/;
		}

	}

	wclosedir(dir);
	return /*success*/ 1;
#else
	return /*failure*/ 0;
#endif
}

/* Store file name to locate.db */
static void
db_store(const wchar_t *dirname)
{
#ifdef WIN32
	if (!db) {
		wprintf(L"Database not open\n");
		exit(EXIT_FAILURE);
	}

	/* Output line to file */
	fwprintf(db, L"%s\n", dirname);
#endif
}

/* Open database file locate.db */
static void
db_open(void)
{
#ifdef WIN32
	if (db)
		return;

	/* Open file for writing */
	errno_t error = _wfopen_s(&db, DB_LOCATION, L"wt, ccs=UNICODE");
	if (error) {
		wprintf(L"Cannot open %s\n", DB_LOCATION);
		exit(EXIT_FAILURE);
	}
#endif
}

/* Close database file */
static void
db_close(
	void)
{
	if (!db)
		return;

	/* Close file */
	fclose(db);
	db = NULL;
}