#include "chess/types.h"
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <chess/util.h>

uint_least64_t rand_64() {
	uint_least64_t u1, u2, u3, u4;
  u1 = (uint_least64_t)(rand()) & 0xFFFF; u2 = (uint_least64_t)(rand()) & 0xFFFF;
  u3 = (uint_least64_t)(rand()) & 0xFFFF; u4 = (uint_least64_t)(rand()) & 0xFFFF;
  return u1 | (u2 << 16) | (u3 << 32) | (u4 << 48);
}

uint_least64_t zobristPieceI(struct piece_t piece, uint_least8_t field) {
	return field * 2 * PIECES_LENGTH + piece.color * PIECES_LENGTH + piece.type;
}

uint_least8_t getFile(const uint_least8_t field) {
	return field % BOARD_SIZE;
}

uint_least8_t getRank(const uint_least8_t field) {
	return field / BOARD_SIZE;
}

struct zobristTable initZobirstTable(struct zobristTableElement *table, size_t length) {
	for(size_t i = 0; i < length; ++i) {
		table[i].hash = 0;
	}
	return (struct zobristTable){table, length};
}

static size_t zobristTableInitialI(const struct zobristTable table, const uint_least64_t key) {
	return key % table.length;
}

void zobristTableIter(const struct zobristTable table, const uint_least64_t key, void *result,
		void (*callback)(struct zobristTableElement *element, const uint_least64_t key, void *result)) {
	const size_t initI = zobristTableInitialI(table, key);
	size_t i = initI;
	do {
		struct zobristTableElement *element = table.arr + i;
		if(element->hash == 0 || element->hash == key) {
			callback(element, key, result);
		}
		++i;
		if(i >= table.length) i = 0;
	} while(i != initI);
	fprintf(stderr, "Error: zobrist table is full");
	exit(1);
}

static void zobristTableItemPtrCallback(struct zobristTableElement *element, const uint_least64_t key,
		void *resultVoid) {
	struct zobristTableElement **result = resultVoid;
	if(element->hash == key) {
		*result = element;
		return;
	} // if(hash == 0)
	*result = NULL;
}

static struct zobristTableElement* zobristTableItemPtr(const struct zobristTable table, const uint_least64_t key) {
	struct zobristTableElement *result;
	zobristTableIter(table, key, &result, zobristTableItemPtrCallback);
	return result;
}

void zobristTableDelete(struct zobristTable table, const uint_least64_t key) {
	struct zobristTableElement *element = zobristTableItemPtr(table, key);
	if(element != NULL) element->hash = 0;
}

int_least16_t* zobristTableGetPtr(const struct zobristTable table, const uint_least64_t key) {
	struct zobristTableElement *element = zobristTableItemPtr(table, key);
	if(element == NULL) return NULL;
	return &element->value;
}