/*
Minetest
Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.

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 Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#include "filesys.h"
#include "util/string.h"
#include <iostream>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <fstream>
#include "log.h"
#include "config.h"

namespace fs
{

#ifdef _WIN32 // WINDOWS

#define _WIN32_WINNT 0x0501
#include <windows.h>

std::vector<DirListNode> GetDirListing(std::string pathstring)
{
	std::vector<DirListNode> listing;

	WIN32_FIND_DATA FindFileData;
	HANDLE hFind = INVALID_HANDLE_VALUE;
	DWORD dwError;

	std::string dirSpec = pathstring + "\\*";
	
	// Find the first file in the directory.
	hFind = FindFirstFile(dirSpec.c_str(), &FindFileData);

	if (hFind == INVALID_HANDLE_VALUE) {
		dwError = GetLastError();
		if (dwError != ERROR_FILE_NOT_FOUND && dwError != ERROR_PATH_NOT_FOUND) {
			errorstream << "GetDirListing: FindFirstFile error."
					<< " Error is " << dwError << std::endl;
		}
	} else {
		// NOTE:
		// Be very sure to not include '..' in the results, it will
		// result in an epic failure when deleting stuff.

		DirListNode node;
		node.name = FindFileData.cFileName;
		node.dir = FindFileData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY;
		if (node.name != "." && node.name != "..")
			listing.push_back(node);

		// List all the other files in the directory.
		while (FindNextFile(hFind, &FindFileData) != 0) {
			DirListNode node;
			node.name = FindFileData.cFileName;
			node.dir = FindFileData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY;
			if(node.name != "." && node.name != "..")
				listing.push_back(node);
		}

		dwError = GetLastError();
		FindClose(hFind);
		if (dwError != ERROR_NO_MORE_FILES) {
			errorstream << "GetDirListing: FindNextFile error."
					<< " Error is " << dwError << std::endl;
			listing.clear();
			return listing;
 		}
	}
	return listing;
}

bool CreateDir(std::string path)
{
	bool r = CreateDirectory(path.c_str(), NULL);
	if(r == true)
		return true;
	if(GetLastError() == ERROR_ALREADY_EXISTS)
		return true;
	return false;
}

bool PathExists(std::string path)
{
	return (GetFileAttributes(path.c_str()) != INVALID_FILE_ATTRIBUTES);
}

bool IsDir(std::string path)
{
	DWORD attr = GetFileAttributes(path.c_str());
	return (attr != INVALID_FILE_ATTRIBUTES &&
			(attr & FILE_ATTRIBUTE_DIRECTORY));
}

bool IsDirDelimiter(char c)
{
	return c == '/' || c == '\\';
}

bool RecursiveDelete(std::string path)
{
	infostream<<"Recursively deleting \""<<path<<"\""<<std::endl;

	DWORD attr = GetFileAttributes(path.c_str());
	bool is_directory = (attr != INVALID_FILE_ATTRIBUTES &&
			(attr & FILE_ATTRIBUTE_DIRECTORY));
	if(!is_directory)
	{
		infostream<<"RecursiveDelete: Deleting file "<<path<<std::endl;
		//bool did = DeleteFile(path.c_str());
		bool did = true;
		if(!did){
			errorstream<<"RecursiveDelete: Failed to delete file "
					<<path<<std::endl;
			return false;
		}
	}
	else
	{
		infostream<<"RecursiveDelete: Deleting content of directory "
				<<path<<std::endl;
		std::vector<DirListNode> content = GetDirListing(path);
		for(int i=0; i<content.size(); i++){
			const DirListNode &n = content[i];
			std::string fullpath = path + DIR_DELIM + n.name;
			bool did = RecursiveDelete(fullpath);
			if(!did){
				errorstream<<"RecursiveDelete: Failed to recurse to "
						<<fullpath<<std::endl;
				return false;
			}
		}
		infostream<<"RecursiveDelete: Deleting directory "<<path<<std::endl;
		//bool did = RemoveDirectory(path.c_str();
		bool did = true;
		if(!did){
			errorstream<<"Failed to recursively delete directory "
					<<path<<std::endl;
			return false;
		}
	}
	return true;
}

bool DeleteSingleFileOrEmptyDirectory(std::string path)
{
	DWORD attr = GetFileAttributes(path.c_str());
	bool is_directory = (attr != INVALID_FILE_ATTRIBUTES &&
			(attr & FILE_ATTRIBUTE_DIRECTORY));
	if(!is_directory)
	{
		bool did = DeleteFile(path.c_str());
		return did;
	}
	else
	{
		bool did = RemoveDirectory(path.c_str());
		return did;
	}
}

std::string TempPath()
{
	DWORD bufsize = GetTempPath(0, "");
	if(bufsize == 0){
		errorstream<<"GetTempPath failed, error = "<<GetLastError()<<std::endl;
		return "";
	}
	std::vector<char> buf(bufsize);
	DWORD len = GetTempPath(bufsize, &buf[0]);
	if(len == 0 || len > bufsize){
		errorstream<<"GetTempPath failed, error = "<<GetLastError()<<std::endl;
		return "";
	}
	return std::string(buf.begin(), buf.begin() + len);
}

#else // POSIX

#include <sys/types.h>
#include <dirent.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <unistd.h>

std::vector<DirListNode> GetDirListing(std::string pathstring)
{
	std::vector<DirListNode> listing;

	DIR *dp;
	struct dirent *dirp;
	if((dp = opendir(pathstring.c_str())) == NULL) {
		//infostream<<"Error("<<errno<<") opening "<<pathstring<<std::endl;
		return listing;
	}

	while ((dirp = readdir(dp)) != NULL) {
		// NOTE:
		// Be very sure to not include '..' in the results, it will
		// result in an epic failure when deleting stuff.
		if(strcmp(dirp->d_name, ".") == 0 || strcmp(dirp->d_name, "..") == 0)
			continue;

		DirListNode node;
		node.name = dirp->d_name;

		int isdir = -1; // -1 means unknown

		/*
			POSIX doesn't define d_type member of struct dirent and
			certain filesystems on glibc/Linux will only return
			DT_UNKNOWN for the d_type member.

			Also we don't know whether symlinks are directories or not.
		*/
#ifdef _DIRENT_HAVE_D_TYPE
		if(dirp->d_type != DT_UNKNOWN && dirp->d_type != DT_LNK)
			isdir = (dirp->d_type == DT_DIR);
#endif /* _DIRENT_HAVE_D_TYPE */

		/*
			Was d_type DT_UNKNOWN, DT_LNK or nonexistent?
			If so, try stat().
		*/
		if(isdir == -1) {
			struct stat statbuf;
			if (stat((pathstring + "/" + node.name).c_str(), &statbuf))
				continue;
			isdir = ((statbuf.st_mode & S_IFDIR) == S_IFDIR);
		}
		node.dir = isdir;
		listing.push_back(node);
	}
	closedir(dp);

	return listing;
}

bool CreateDir(std::string path)
{
	int r = mkdir(path.c_str(), S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH);
	if(r == 0)
	{
		return true;
	}
	else
	{
		// If already exists, return true
		if(errno == EEXIST)
			return true;
		return false;
	}
}

bool PathExists(std::string path)
{
	struct stat st;
	return (stat(path.c_str(),&st) == 0);
}

bool IsDir(std::string path)
{
	struct stat statbuf;
	if(stat(path.c_str(), &statbuf))
		return false; // Actually error; but certainly not a directory
	return ((statbuf.st_mode & S_IFDIR) == S_IFDIR);
}

bool IsDirDelimiter(char c)
{
	return c == '/';
}

bool RecursiveDelete(std::string path)
{
	/*
		Execute the 'rm' command directly, by fork() and execve()
	*/
	
	infostream<<"Removing \""<<path<<"\""<<std::endl;

	//return false;
	
	pid_t child_pid = fork();

	if(child_pid == 0)
	{
		// Child
		char argv_data[3][10000];
		strcpy(argv_data[0], "/bin/rm");
		strcpy(argv_data[1], "-rf");
		strncpy(argv_data[2], path.c_str(), 10000);
		char *argv[4];
		argv[0] = argv_data[0];
		argv[1] = argv_data[1];
		argv[2] = argv_data[2];
		argv[3] = NULL;

		verbosestream<<"Executing '"<<argv[0]<<"' '"<<argv[1]<<"' '"
				<<argv[2]<<"'"<<std::endl;
		
		execv(argv[0], argv);
		
		// Execv shouldn't return. Failed.
		_exit(1);
	}
	else
	{
		// Parent
		int child_status;
		pid_t tpid;
		do{
			tpid = wait(&child_status);
			//if(tpid != child_pid) process_terminated(tpid);
		}while(tpid != child_pid);
		return (child_status == 0);
	}
}

bool DeleteSingleFileOrEmptyDirectory(std::string path)
{
	if(IsDir(path)){
		bool did = (rmdir(path.c_str()) == 0);
		if(!did)
			errorstream<<"rmdir errno: "<<errno<<": "<<strerror(errno)
					<<std::endl;
		return did;
	} else {
		bool did = (unlink(path.c_str()) == 0);
		if(!did)
			errorstream<<"unlink errno: "<<errno<<": "<<strerror(errno)
					<<std::endl;
		return did;
	}
}

std::string TempPath()
{
	/*
		Should the environment variables TMPDIR, TMP and TEMP
		and the macro P_tmpdir (if defined by stdio.h) be checked
		before falling back on /tmp?

		Probably not, because this function is intended to be
		compatible with lua's os.tmpname which under the default
		configuration hardcodes mkstemp("/tmp/lua_XXXXXX").
	*/
#ifdef __ANDROID__
	return DIR_DELIM "sdcard" DIR_DELIM PROJECT_NAME DIR_DELIM "tmp";
#else
	return DIR_DELIM "tmp";
#endif
}

#endif

void GetRecursiveSubPaths(std::string path, std::vector<std::string> &dst)
{
	std::vector<DirListNode> content = GetDirListing(path);
	for(unsigned int  i=0; i<content.size(); i++){
		const DirListNode &n = content[i];
		std::string fullpath = path + DIR_DELIM + n.name;
		dst.push_back(fullpath);
		if (n.dir) {
			GetRecursiveSubPaths(fullpath, dst);
		}
	}
}

bool DeletePaths(const std::vector<std::string> &paths)
{
	bool success = true;
	// Go backwards to succesfully delete the output of GetRecursiveSubPaths
	for(int i=paths.size()-1; i>=0; i--){
		const std::string &path = paths[i];
		bool did = DeleteSingleFileOrEmptyDirectory(path);
		if(!did){
			errorstream<<"Failed to delete "<<path<<std::endl;
			success = false;
		}
	}
	return success;
}

bool RecursiveDeleteContent(std::string path)
{
	infostream<<"Removing content of \""<<path<<"\""<<std::endl;
	std::vector<DirListNode> list = GetDirListing(path);
	for(unsigned int i=0; i<list.size(); i++)
	{
		if(trim(list[i].name) == "." || trim(list[i].name) == "..")
			continue;
		std::string childpath = path + DIR_DELIM + list[i].name;
		bool r = RecursiveDelete(childpath);
		if(r == false)
		{
			errorstream<<"Removing \""<<childpath<<"\" failed"<<std::endl;
			return false;
		}
	}
	return true;
}

bool CreateAllDirs(std::string path)
{

	std::vector<std::string> tocreate;
	std::string basepath = path;
	while(!PathExists(basepath))
	{
		tocreate.push_back(basepath);
		basepath = RemoveLastPathComponent(basepath);
		if(basepath.empty())
			break;
	}
	for(int i=tocreate.size()-1;i>=0;i--)
		if(!CreateDir(tocreate[i]))
			return false;