//
// Created by haraldwolff on 08.08.22.
//

#include <merkle.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

int highest_one(long l){
	long test = 1l<<63;

	for (int n=63; n>=0 ; n--)
	{
		if (l & test)
			return n;
		test >>= 1;
	}
	return -1;
}

int merkle_create(merkle_t **merkle, int n, int minwidth){
	*merkle = malloc(sizeof(merkle_t));
	if (!*merkle)
		return -ENOMEM;

	memset( *merkle, 0x00, sizeof(merkle_t));

	int s = merkle_init(*merkle, n, minwidth);
	if (s){
		free(*merkle);
		return s;
	}
	(*merkle)->flags |= MF_ALLOC;

	return 0;
}

int merkle_init(merkle_t *merkle, int n, int minwidth){
	int l = 0;
	int _width = 1;
	int length = 1;

	while (_width < minwidth){
		l++;
		_width *= n;
		length += _width;
	}

	merkle->indeces = malloc(sizeof(int)*(l+1));
	if (!merkle->indeces)
		return -ENOMEM;

	merkle->hashes = malloc(sizeof(uint64_t)*length);
	if (!merkle->hashes) {
		free(merkle->indeces);
		return -ENOMEM;
	}

	merkle->parameters.n = n;
	merkle->parameters.depth = l;
	merkle->parameters.width = _width;
	merkle->parameters.length = length;

	merkle->indeces[0] = 0;
	if (l > 0)
	{
		int i = 1;
		for (int d=1;d<=l;d++){
			merkle->indeces[d] = merkle->indeces[d-1] + i;
			i*=n;
		}
	}

	memset(merkle->hashes, 0x00, sizeof(uint64_t) * length );

	return 0;
}


int merkle_free(merkle_t *merkle){
	if (merkle){
		if (merkle->hashes)
			free(merkle->hashes);
		if (merkle->indeces)
			free(merkle->indeces);
		if (merkle->flags & MF_ALLOC)
			free(merkle);
		return 0;
	}
	return -EINVAL;
}

int merkle_get(merkle_t *merkle, int level, int n, uint64_t *hash){
	uint64_t *row;
	int rowlength;
	int s = merkle_get_row(merkle, level, &row, &rowlength);
	if (s < 0)
		return s;
	for (int i=level;i<merkle->parameters.depth;i++)
		n /= merkle->parameters.n;
	if (hash)
		*hash = row[n];
	return 0;
}
int merkle_set(merkle_t *merkle, int level, int n, uint64_t hash){
	uint64_t *row;
	int rowlength;
	int s = merkle_get_row(merkle, level, &row, &rowlength);
	if (s < 0)
		return s;
	for (int i=0;i<level;i++)
		n /= merkle->parameters.n;
	row[n] = hash;
	return 0;
}

int merkle_get_row(merkle_t *merkle, int level, uint64_t **offset, int *size){
	if (!merkle)
		return -EINVAL;
	if ((level<0) || (level > merkle->parameters.depth))
		return -EINVAL;

	if (offset)
		*offset = &merkle->hashes[merkle->indeces[level]];
	if (size)
		*size = merkle->indeces[level]+1;

	return merkle->indeces[level];
}