#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "vector.h"
#include "chesshelpers.h"

board_t init_board(int** pieces) {
	board_t board;
	board.pieces = pieces;
	board.whiteCanCastleKingside = 1;
	board.whiteCanCastleQueenside = 1;
	board.blackCanCastleKingside = 1;
	board.blackCanCastleQueenside = 1;
	board.lastPawnMove = -1;
	return board;
}
//function applies side effects to board values like king move state
board_t make_move(board_t board, vector_t origin, vector_t end) {
	int piece = board.pieces[origin.mx][origin.my];
	board.pieces[origin.mx][origin.my] = 0;
	board.pieces[end.mx][end.my] = piece;
	//white king moved
	if(piece == king) {
		board.whiteCanCastleQueenside = 0;
		board.whiteCanCastleKingside = 0;
		//if the king moved farther than it normally could, move must have been castling. move the rook as well
		if(origin.mx == 4 && end.mx == 6) {
			board = make_move(board, init_vector(7, 7), init_vector(5, 7));
		}
		else if(origin.mx == 4 && end.mx == 2) {
			board = make_move(board, init_vector(0, 7), init_vector(3, 7));
		}
	}
	//white kingside rook moved
	else if(origin.mx == 7 && origin.my == 7) {
		board.whiteCanCastleKingside = 0;
	}
	//white queenside rook moved
	else if(origin.mx == 0 && origin.my == 7) {
		board.whiteCanCastleQueenside = 0;
	}
	//black king moved
	else if(piece == king + 6) {
		board.blackCanCastleQueenside = 0;
		board.blackCanCastleKingside = 0;
		//if the king moved farther than it normally could, move must have been castling. move the rook as well
		if(origin.mx == 4 && end.mx == 6) {
			board = make_move(board, init_vector(7, 0), init_vector(5, 0));
		}
		else if(origin.mx == 4 && end.mx == 2) {
			board = make_move(board, init_vector(0, 0), init_vector(3, 0));
		}
	}
	//black kingside rook moved
	else if(origin.mx == 7 && origin.my == 0) {
		board.blackCanCastleKingside = 0;
	}
	//black queenside rook moved
	else if(origin.mx == 0 && origin.my == 0) {
		board.blackCanCastleQueenside = 0;
	}
	//this is not an else if! lastPawnMove must be reset
	if(piece == pawn || piece == pawn + 6) {
		board.lastPawnMove = origin.mx;
	}
	else {
		//en passant no longer possible
		board.lastPawnMove = -1;
	}
	return board;
}
board_t clone_board(board_t board) {
	board_t newBoard = board;
	int** pieces = malloc(8 * sizeof(int*));
	for(int r = 0; r < 8; r++) {
		pieces[r] = malloc(8 * sizeof(int));
		for(int c = 0; c < 8; c++) {
			pieces[r][c] = board.pieces[r][c];
		}
	}
	newBoard.pieces = pieces;
	return newBoard;
}
int in_board(vector_t position) {
	return position.mx < 8 && position.mx >= 0 && position.my < 8 && position.my >= 0;
}
int is_empty(board_t board, vector_t position) {
	return board.pieces[position.mx][position.my] == 0;
}
int is_color(board_t board, vector_t position, int color) {
	if(color == 0) {
		return board.pieces[position.mx][position.my] >= 1 && board.pieces[position.mx][position.my] <= 6;
	}	
	else {
		return board.pieces[position.mx][position.my] >= 7;
	}
}
//converts board coordinates into algebraic notation
char* get_readable_coords(vector_t position) {
	char* output = malloc(3 * sizeof(char));
	output[0] = 'a' + position.mx;
	output[1] = '8' - position.my;
	output[2] = '\0';
	return output;
}
//gets the proper algebraic notation for the move
char* get_move_name(board_t board, vector_t origin, vector_t end) {
	int piece = board.pieces[origin.mx][origin.my];
	if(piece > 6) {
		piece -= 6;
	}
	if(piece != 1) {
		char cPiece = piece == pawn ? 'P' : piece == knight ? 'N' : piece == bishop ? 'B' : piece == rook ? 'R' : piece == queen ? 'Q' : 'K';
		int isCapture = board.pieces[end.mx][end.my] != 0;
		char* output = calloc(isCapture ? 5 : 4, sizeof(char));
		output[0] = cPiece;
		if(isCapture) {
			output[1] = 'x';
		}
		char* rEnd = get_readable_coords(end);
		strcat(output, rEnd);
		free(rEnd);
		output[isCapture ? 4 : 3] = '\0';
		return output;
	}
	else {
		int isCapture = board.pieces[end.mx][end.my] != 0;
		char* output = calloc(isCapture ? 5 : 3, sizeof(char));
		if(isCapture) {
			output[0] = 'a' + origin.mx;
			output[1] = 'x';
		}
		char* rEnd = get_readable_coords(end);
		strcat(output, rEnd);
		free(rEnd);
		output[isCapture ? 4 : 2] = '\0';
		return output;
	}
}