#include <stdio.h>
#include <memory.h>
#include <stdlib.h>
#include <cstdint>


typedef struct
{
	char fen[100];
	int leftFenNumber;
	int rightFenNumber;
	int leftEval;
	char leftMove[10];
	int leftRank;
	int rightEval;
	char rightMove[10];
	int rightRank;
} position_t;

position_t *gPosition = NULL;
int gPositions;


void StripTrailingNewline(char *str)
{
	int sl = strlen(str);
	
	if (sl == 0)
		return;
	if (str[sl - 1] == '\n')
		str[sl - 1] = 0;
}


uint32_t MyHashString(const char *s)
{
	uint32_t hash = 2166136261u;
	
	while (*s)
		{
		hash ^= (unsigned char)*s++;
		hash *= 16777619u;
		}
	return hash;
}


int CompareLeftEvals(const void *a, const void *b)
{
	position_t *pa = (position_t *)a;
	position_t *pb = (position_t *)b;
	
	if (pa->leftEval == pb->leftEval)
		return pa->leftFenNumber - pb->leftFenNumber;
	return pb->leftEval - pa->leftEval;
}


int CompareRightEvals(const void *a, const void *b)
{
	position_t *pa = (position_t *)a;
	position_t *pb = (position_t *)b;
	
	if (pa->rightEval == pb->rightEval)
		return pa->rightFenNumber - pb->rightFenNumber;
	return pb->rightEval - pa->rightEval;
}


void PrintCorrelation()
{
	double accuracy;
	double totalAccuracy = 0;
	double sameMove = 0;
	int i;
	
	for (i = 0; i < gPositions; ++i)
		{
		accuracy = abs(gPosition[i].leftRank - gPosition[i].rightRank);
		accuracy /= (double)gPositions;
		accuracy = 1.0 - accuracy;
		totalAccuracy += accuracy;
		
		if (gPosition[i].leftMove[0] != 0 &&
				!strcmp(gPosition[i].leftMove, gPosition[i].rightMove))
			sameMove += 1.0;
		}
	printf("  Positions: %d\n", gPositions);
	printf("  Eval correlation: %0.3f percent\n", (totalAccuracy / (double)gPositions) * 100.0);
	printf("  Move correlation: %0.3f percent\n", (sameMove / (double)gPositions) * 100.0);
}


void StoreFileEval(char *fen, int fenNumber, int eval, char *moveString, bool isLeftFile)
{
	int fenHash = (int)MyHashString(fen);
	int i;
	
	i = abs(fenHash) % 1500000;
	for (;;)
		{
		if (gPosition[i].fen[0] == 0)
			{
			strcpy(gPosition[i].fen, fen);
			break;
			}
		if (!strcmp(gPosition[i].fen, fen))
			break;
		i++;
		}
	if (isLeftFile)
		{
		gPosition[i].leftFenNumber = fenNumber;
		gPosition[i].leftEval = eval;
		strcpy(gPosition[i].leftMove, moveString);
		}
	else
		{
		gPosition[i].rightFenNumber = fenNumber;
		gPosition[i].rightEval = eval;
		strcpy(gPosition[i].rightMove, moveString);
		}
}


void ReadFileEvals(const char *fileName, bool isLeftFile)
{
	FILE *f;
	char fenLine[1000 + 1];
	char evalLine[1000 + 1];
	char moveLine[1000 + 1];
	int fenNumber;
	
	f = fopen(fileName, "r");
	if (!f)
		{
		printf("Couldn't open %s.\n", fileName);
		exit(1);
		}
	fenNumber = 0;
	for (;;)
		{
		fenLine[0] = 0;
		evalLine[0] = 0;
		moveLine[0] = 0;
		fgets(fenLine, 1000, f);
		fgets(evalLine, 1000, f);
		fgets(moveLine, 1000, f);
		if (fenLine[0] == 0 || evalLine[0] == 0 || moveLine[0] == 0)
			break;		
		StripTrailingNewline(fenLine);
		StripTrailingNewline(evalLine);
		StripTrailingNewline(moveLine);
		StoreFileEval(fenLine, fenNumber, atoi(evalLine), moveLine, isLeftFile);
		fenNumber++;
		}
	fclose(f);
}


void CompareLopFiles(const char *leftFile, const char *rightFile)
{
	int i;
	
	printf("Comparing %s to %s:\n", leftFile, rightFile);
	fflush(stdout);
	
	if (gPosition)
		free(gPosition);
	gPosition = (position_t *)malloc(2000000 * sizeof(position_t));
	gPositions = 0;
	for (i = 0; i < 2000000; ++i)	
		{
		gPosition[i].fen[0] = 0;
		gPosition[i].leftEval = -1000000;
		gPosition[i].rightEval = -1000000;
		}
	
	ReadFileEvals(leftFile, true);
	ReadFileEvals(rightFile, false);
	
	position_t *oldPosition = gPosition;
	gPosition = (position_t *)malloc(2000000 * sizeof(position_t));
	gPositions = 0;
	for (i = 0; i < 2000000; ++i)
		{
		if (oldPosition[i].fen[0] == 0 ||
				oldPosition[i].leftEval == -1000000 ||
				oldPosition[i].rightEval == -1000000)
			continue;
		gPosition[gPositions++] = oldPosition[i];
		}
	free(oldPosition);
	
	qsort(gPosition, gPositions, sizeof(position_t), CompareLeftEvals);
	for (i = 0; i < gPositions; ++i)
		gPosition[i].leftRank = i;

	qsort(gPosition, gPositions, sizeof(position_t), CompareRightEvals);
	for (i = 0; i < gPositions; ++i)
		gPosition[i].rightRank = i;
	
	PrintCorrelation();

	free(gPosition);
	gPosition = NULL;
}


int main(int argc, char *argv[])
{
	char leftFile[1000 + 1];
	char rightFile[1000 + 1];
	
	/*strcpy(leftFile, "lop_10k_lc0_nosearch.txt");
	strcpy(rightFile, "lop_10k_sf.txt");
	CompareLopFiles(leftFile, rightFile);
	return 0;*/

	if (argc != 3)
		{
		printf("Usage: compare_lop file_one.txt file_two.txt\n");
		exit(1);
		}
	strcpy(leftFile, argv[1]);
	strcpy(rightFile, argv[2]);
	CompareLopFiles(leftFile, rightFile);
	return 0;
}