// Primer labi ¹ 3 - klient-servernoe prilozenie Windows
// server

#include <conio.h>
#include <iostream>
#include <windows.h>

#define FILENAME "userdata" 
#define ADD_USER '1'
#define EDIT_USER '2'
#define DELETE_USER '3'
#define CHANGE_PWD '4'
#define VIEW_USERS '5'
#define ADD_RATING '6'
#define PURGE '7'
#define FINISH '8'

using namespace std;


struct User{ 
	int exist;	// 0 - if deleted, 1 - otherwise
	char login[11];
	char passwd[21];
	int rating;
	User(){		// constructor
		exist=0;
		login[0]=0;
		passwd[0]=0;
		rating=0;
	}
};

// main functions
void Add_User();
void Print_Users();
void Edit_User();
int Find_User();
void Delete_User();
void Change_Pwd();
void Add_Rating();
void Purge();
// service functions
void load();
void save();
void openPipe();
void initStrings();
void myExit();

int quant;		//number of records
struct User *arr;	//array for data

HANDLE hPipe;	// Pipe handle

wchar_t *pipename= L"\\\\.\\pipe\\oslab3";

int main(int argc, char* argv[]){
	int code=0;	//kod operacii, proslannoi klientom

	load();

	openPipe();

	// Main cycle of program
	// Chitaem kod commandi, poka ne vstretitsia 8
	while(code!=FINISH){
		int retCode;
		DWORD bytesRead;
		retCode=ReadFile(hPipe,(void*)&code,sizeof(int),&bytesRead,NULL);
		if(!retCode){
			printf("Couldn't read action code");
			myExit();
		}
		switch(code){
			case ADD_USER:Add_User();break;
			case VIEW_USERS:Print_Users();break;
			case EDIT_USER:Edit_User();break;
			case DELETE_USER:Delete_User();break;
			case CHANGE_PWD:Change_Pwd();break;
			case ADD_RATING:Add_Rating();break;
			case PURGE:Purge();break;
			default: break;
		}
	}
	save();
	myExit();
	return 0;
}

void myExit(){
	CloseHandle(hPipe);	// Close pipe handle
	printf("Server finish its work. Press any key to exit ...");
	_getch();
	exit(0);
}

void openPipe(){
	// Zdem osvobozdenia kanala 20 sekund
	if (!WaitNamedPipe(pipename, 20000)){ 
         printf("No free pipe."); 
         myExit();
    }
	// open pipe
	hPipe = CreateFile(pipename,GENERIC_READ|GENERIC_WRITE,0,NULL,OPEN_EXISTING,0,NULL);
	if(hPipe == INVALID_HANDLE_VALUE) {
		printf("Could not open pipe"); 
        myExit();
	}
	// Ustanovit' rezim chtenia soobshenii
	DWORD dwMode = PIPE_READMODE_MESSAGE;
    int fSuccess = SetNamedPipeHandleState(hPipe,&dwMode,NULL,NULL);
    if (!fSuccess){
		printf("SetNamedPipeHandleState failed"); 
		myExit();
    }

}

void Add_User(){
	//Videlenie massivqa dlinoq na 1 bolshe predidushego
	struct User* tmp_arr = new User[quant+1];
	//Perepisivaem starii massiv
	memcpy(tmp_arr,arr,sizeof(struct User)*quant);
	delete[] arr;
	arr = tmp_arr;
	User tmpUser;
	int retCode;
	DWORD bytesRead;
	// Polutchit' opisanie nivigi polzovatelia v User
	retCode=ReadFile(hPipe,(void*)&tmpUser,sizeof(User),&bytesRead,NULL);
	if(!retCode || bytesRead!=sizeof(User)){
		printf("Can't read new user from pipe");
		myExit();
	}
	arr[quant]=tmpUser;
	quant++;
}


void Print_Users(){
	int	i,	
		st=0, // number of real records
		retCode;
	DWORD bytesWritten;
	for(i=0;i<quant;i++)
		if(arr[i].exist)// if record isn't deleted
			st++;
	// Send to client number of records
	retCode=WriteFile(hPipe,(void*)&st,sizeof(int),&bytesWritten,NULL);
	if(!retCode || bytesWritten!=sizeof(int)){
		printf("Can't write number of student to pipe for output");
		myExit();
	}
	// Send one user per one cycle iteration
	for(i=0;i<quant;i++)
		if(arr[i].exist)
		{
			retCode=WriteFile(hPipe,(void*)&arr[i],sizeof(User),&bytesWritten,NULL);
			if(!retCode || bytesWritten!=sizeof(User)){
				printf("Can't write student to pipe");
				myExit();
			}
		}
}

void Edit_User(){
	int i,		// Number of edited user
		retCode;
	DWORD bytesRead,bytesWritten;
	User tmpUser;
	i=Find_User(); 
	if(i==-1)return;   // Search fails
	// Send old user information
	retCode=WriteFile(hPipe,(void*)&arr[i],sizeof(User),&bytesWritten,NULL);
	if(!retCode || bytesWritten!=sizeof(User)){
		printf("Can't write student to pipe for edition");
		myExit();
	}
	// Read new user information
	retCode=ReadFile(hPipe,(void*)&tmpUser,sizeof(User),&bytesRead,NULL);
	if(!retCode || bytesRead!=sizeof(User)){
		printf("Can't read edited user from pipe");
		myExit();
	}
	strcpy_s(arr[i].login,11,tmpUser.login);
	strcpy_s(arr[i].passwd,21,tmpUser.passwd); 
	arr[i].rating=tmpUser.rating;/
}


int Find_User(){
	int		i,	// i - ïîðÿäêîâûé íîìåð èñêîìîé çàï;
			fl1,// fl1 - Flag - priznak uspeshnoi zapisi
			res,// res - vozvrashaemoe znachenie - libo nomer zapisi libo kod neudachi poiska 
			retCode;
	DWORD bytesRead,bytesWritten;
	User tmpUser;

	res=-1;
	while(res==-1)
	{
		// read login
		retCode=ReadFile(hPipe,(void*)&tmpUser,sizeof(User),&bytesRead,NULL);
		if(!retCode || bytesRead!=sizeof(User)){
			printf("Can't read user login from pipe");
			myExit();
		}
		if(tmpUser.exist==-1)// if client otpravil otkaz ot zapisi
			return -1;
		fl1=0;i=0; 
		while(!fl1 && i<quant)
		{ 
			if(arr[i].exist)
				if(strcmp(tmpUser.login,arr[i].login)==0)
				{
					fl1=1;
					res=i;/
				}
				i++;
		}
		if(res==-1)
			tmpUser.exist=-1; // Ustanovit privnak togo chto ne nashli fail
		else
			tmpUser.exist=777;// Ustanovit privnak togo chto nashli fail
		// Send results to client and wait response
		retCode=WriteFile(hPipe,(void*)&tmpUser,sizeof(User),&bytesWritten,NULL);
		if(!retCode || bytesWritten!=sizeof(User)){
			printf("Can't write search results to pipe");
			myExit();
		}
	}
	return res;
}

void Delete_User(){
	int i,
		retCode;
	DWORD bytesWritten;
	User tmpUser;
	i=Find_User(); 
	if(i==-1)return;
	arr[i].exist=0;
	tmpUser.exist=777;
	retCode=WriteFile(hPipe,(void*)&tmpUser,sizeof(User),&bytesWritten,NULL);
	if(!retCode || bytesWritten!=sizeof(User)){
		printf("Can't write delete result to pipe");
		myExit();
	}
}

void Change_Pwd(){
	int i,
		retCode;
	DWORD bytesRead,bytesWritten;
	User tmpUser;
	i=Find_User(); 
	if(i==-1)return; 
	retCode=WriteFile(hPipe,(void*)&arr[i],sizeof(User),&bytesWritten,NULL);
	if(!retCode || bytesWritten!=sizeof(User)){
		printf("Can't write student to pipe for password changing");
		myExit();
	}
	retCode=ReadFile(hPipe,(void*)&tmpUser,sizeof(User),&bytesRead,NULL);
	if(!retCode || bytesRead!=sizeof(User)){
		printf("Can't read edited password from pipe");
		myExit();
	}
	strcpy_s(arr[i].passwd,21,tmpUser.passwd);
}

void Add_Rating(){
	int i,
		retCode;
	DWORD bytesRead,bytesWritten;
	User tmpUser;
	i=Find_User(); 
	if(i==-1)return;  
	retCode=WriteFile(hPipe,(void*)&arr[i],sizeof(User),&bytesWritten,NULL);
	if(!retCode || bytesWritten!=sizeof(User)){
		printf("Can't write student to pipe for password edition");
		myExit();
	}
	retCode=ReadFile(hPipe,(void*)&tmpUser,sizeof(User),&bytesRead,NULL);
	if(!retCode || bytesRead!=sizeof(User)){
		printf("SERVER: Can't read edited password from pipe");
		myExit();
	}
	arr[i].rating+=tmpUser.rating; 
}

void Purge(){
	int i,j;
	printf("Please wait while purging database\n");
	int rec_num=0;
	for(int i=0;i<quant;i++)
		if(arr[i].exist!=0)
			rec_num++;
	struct User* tmp_arr = new User[rec_num];
	j=0;
	for(i=0;i<quant;i++) 
		if(arr[i].exist){
			tmp_arr[j]=arr[i];
			j++;
		}
	delete[] arr;
	arr = tmp_arr;
	quant=rec_num;
	printf("Purging complete\n");
}

void load(){
	int count=0;
	HANDLE file;
	DWORD readBytes,bytesWritten;
	int retCode;
	struct User tmp;
	file = CreateFile(TEXT(FILENAME), GENERIC_WRITE|GENERIC_READ, 0, 0, OPEN_EXISTING, 0, 0);
	if(file == INVALID_HANDLE_VALUE){ // Âûçîâ çàâåðøèëñÿ íåóäà÷åé, ò.å. ôàéëà íå ñóùåñòâóåò
		file = CreateFile(TEXT(FILENAME), GENERIC_WRITE|GENERIC_READ, 0, 0, CREATE_NEW, 0, 0);
		count=0;
		WriteFile(file,(void*)&count,sizeof(int),&bytesWritten,0);
		arr = NULL;
	}
	else {
		retCode=ReadFile(file,(void*)&count, sizeof(int), &readBytes, 0);
		if(!retCode || readBytes!=sizeof(int)){
			printf("Can't read the file.\n");
			count=0;
			arr=NULL;
			return;
		}
		arr = (struct User*)new struct User[count];
		int curNumber=0;
		while(curNumber<count && ReadFile(file,(void*)&arr[curNumber], sizeof(struct User), &readBytes, 0)){ // ïðî÷èòàòü îäíó ñòðóêòóðó
			if(readBytes!=sizeof(struct User))
				break;
			curNumber++;
		}
	}
	CloseHandle(file);
	quant = count;
}

void save(){
	HANDLE file;
	DWORD bytesWritten;
	int retCode;
	file = CreateFile(TEXT(FILENAME),GENERIC_WRITE, 0, NULL,CREATE_ALWAYS, 0, NULL);
	if(file == INVALID_HANDLE_VALUE){
		DWORD le = GetLastError();
		printf("Can't create the file %s.\n",FILENAME);
		return;
	}
	retCode=WriteFile(file,(void*)&quant, sizeof(int), &bytesWritten, 0);
	if(!retCode || bytesWritten!=sizeof(int)){
			printf("Can't write count to the file.\n");
			return;
	}
	int curNumber=0;
	while(WriteFile(file,(void*)&arr[curNumber], sizeof(struct User), &bytesWritten, 0) && curNumber<quant){
		if(bytesWritten!=sizeof(struct User)){
			printf("Can't write structure to the file.\n");
			return;
		}
		curNumber++;
	}
	CloseHandle(file);
}