#include <stdio.h>
#include <string.h>
#include <stdbool.h>

typedef enum Vakje{
	LEEG=0,
	WPION,WTOREN,WPAARD,WLOPER,WKONING,WKONGIN,
	ZPION,ZTOREN,ZPAARD,ZLOPER,ZKONING,ZKONGIN
}Vakje;

char characters[][5] = {".",
	"♟","♜","♞","♝","♛","♚",
	"🨣","🨠","🨢","🨡","🨟","🨞"};

Vakje Bord[] =
{	ZTOREN	,ZPAARD	,ZLOPER	,ZKONING,ZKONGIN,ZLOPER	,ZPAARD	,ZTOREN,
	ZPION	,ZPION	,ZPION	,ZPION	,ZPION	,ZPION	,ZPION	,ZPION,
	LEEG	,LEEG	,LEEG	,LEEG	,LEEG	,LEEG	,LEEG	,LEEG,
	LEEG	,LEEG	,LEEG	,LEEG	,LEEG	,LEEG	,LEEG	,LEEG,
	LEEG	,LEEG	,LEEG	,LEEG	,LEEG	,LEEG	,LEEG	,LEEG,
	LEEG	,LEEG	,LEEG	,LEEG	,LEEG	,LEEG	,LEEG	,LEEG,
	WPION	,WPION	,WPION	,WPION	,WPION	,WPION	,WPION	,WPION,
	WTOREN	,WPAARD	,WLOPER	,WKONING,WKONGIN,WLOPER	,WPAARD	,WTOREN
};

#define ABS(z) z>0 ? z : -z

void printBoard(){
	printf("  ");
	for(int j=0; j<8; j++){
		printf("%c  ",'a'+j);
	}
	printf("\n");
	for(int i=0; i<8; i++){
		printf("%d ", i+1);
		for(int j=0; j<8; j++){
			printf("%s  ",characters[Bord[i*8+j]]);
		}
		printf("\n");
	}
}

bool validBishopMovevment(int i1,int j1,int i2,int j2){
	if( ABS(i1-i2) == ABS(j1-j2) && (i1!=i2 || j1!=j2) ){
		int signJ = (j1 < j2)*2-1;
		int signI = (i1 < i2)*2-1;
		bool alEmpty=true;
		int n = ABS(i1-i2);
		for(int offset =1; offset <n; offset++;){
			int i3= i1+offset*signI;
			int j3= j1+offset*signJ;
			if(Bord[i3+j3*8]!=LEEG){
				alEmpty=false;
				break;
			}

		}
		if(alEmpty)
			return true;;
	}
	printf("It is illegal to move a tower that way\n");
	return false;

}
bool validTowerMovement(int i1,int j1,int i2,int j2){
	if( i1!=i2 && j1==j2  || i1==i2 && j1!=j2 ){
		int i3 = i1;
		int j3 = j1;
		int start,end;
		int*countp;
		if(i1!=i2){
			start = i1;
			end = i2;
			countp = &i3;
		}else{
			start = j1;
			end = j2;
			countp = &j3;
		}
		int sign = (start < end)*2-1;
		bool alEmpty=true;;
		for(*countp = start+sign; sign**countp < sign*end; *countp+=sign){
			if(Bord[i3+j3*8]!=LEEG){
				alEmpty=false;
				break;
			}

		}
		if(alEmpty)
			return true;;
	}
	return false;

}

void main(){
	bool beurt = true;
	printf("Welkom bij schaken\n");
	while(true){
		printBoard();
		if(beurt)
			printf("Wit ");
		else
			printf("Zwart ");

		printf("is aan de beurt:");

		char strFrom[10];
		char strTo[10];
		scanf("%s %s", strFrom, strTo);

#define INV() printf("invalid input\n")

		//check for valid input
		if(strlen(strFrom)<2 || strlen(strTo)<2){
			INV();
			continue;
		}
		int i1,j1,i2,j2;

		if('a'<=strFrom[0]&&strFrom[0]<='h'){
			i1 = strFrom[0]-'a';
		}else{
			INV();
			continue;
		}
		if('1'<=strFrom[1]&&strFrom[1]<='8'){
			j1 = strFrom[1]-'1';
		}else{
			INV();
			continue;
		}
		if('a'<=strTo[0]&&strTo[0]<='h'){
			i2 = strTo[0]-'a';
		}else{
			INV();
			continue;
		}
		if('1'<=strTo[1]&&strTo[1]<='8'){
			j2 = strTo[1]-'1';
		}else{
			INV();
			continue;
		}


		//check if the player is moving a piece of
		//it's own color
		if(Bord[i1+j1*8]==LEEG){
			printf("%s is empty\n", strFrom);
			continue;
		}
		if(
				beurt && Bord[i1+j1*8]>WKONGIN
				||
				!beurt&& Bord[i1+j1*8]<ZPION
				){

			printf("%s is not the right colour\n", strFrom);
			continue;
		}
		//check if the player is not moving a piece to
		//it's own color
		if(
				beurt&& Bord[i2+j2*8]<ZPION && Bord[i2+j2*8]!=LEEG
				||
				!beurt && Bord[i2+j2*8]>WKONGIN
				){

			printf("%s is not the right colour\n", strTo);
			continue;
		}

		int direction = 1-beurt*2;

		//Check, given the piece if the movement is valid
		switch(Bord[i1+j1*8]){
			case(WPION):
			case(ZPION):
				if( j2-j1==direction && i1==i2 && Bord[i2+j2*8] == LEEG)
					break;
				if( j2-j1==direction && (i1-i2 == -1 || i1-i2 == 1) && 
						Bord[i2+j2*8] != LEEG)
					break;
				printf("It is illegal to move a pion that way\n");
				continue;
			case(WTOREN):
			case(ZTOREN):
				if(!validTowerMovement(i1,j1,i2,j2)){
					printf("It is illegal to move a tower that way\n");
					continue;
				}
			case(WPAARD):
			case(ZPAARD):
				if(ABS(i1-i2)==2 && ABS(j1-j2) ==1 || 
					ABS(i1-i2)==1 && ABS(j1-j2) ==2){

					break;
				}
				printf("It is illegal to move a horse that way\n");
				continue;
			case(WKONING):
			case(ZKONING):
				if(ABS(i1-i2)<=1 && ABS(j1-j2)<=1 && (i1!=i2 || j1!=j2)){
					break;
				}
				printf("It is illegal to move a king that way\n");
				continue;
			case(WKONGIN):
			case(ZKONGIN):

			 
		}
		

		//make move
		Bord[i2+j2*8] = Bord[i1+j1*8];
		Bord[i1+j1*8]=LEEG;

		beurt = !beurt;
	}
}