/*
 * $Id$
 *
    Copyright (c) 2016-2018 Chung, Hyung-Hwan. All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions
    are met:
    1. Redistributions of source code must retain the above copyright
       notice, this list of conditions and the following disclaimer.
    2. Redistributions in binary form must reproduce the above copyright
       notice, this list of conditions and the following disclaimer in the
       documentation and/or other materials provided with the distribution.

    THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR
    IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
    OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
    IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
    NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
    THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "hcl-prv.h"

/*#define SYMBOL_ONLY_KEY */

static hcl_oop_oop_t expand_bucket (hcl_t* hcl, hcl_oop_oop_t oldbuc)
{
	hcl_oop_oop_t newbuc;
	hcl_oow_t oldsz, newsz, index;
	hcl_oop_cons_t ass;

	oldsz = HCL_OBJ_GET_SIZE(oldbuc);

	/* TODO: better growth policy? */
	if (oldsz < 5000) newsz = oldsz + oldsz;
	else if (oldsz < 50000) newsz = oldsz + (oldsz / 2);
	else if (oldsz < 100000) newsz = oldsz + (oldsz / 4);
	else if (oldsz < 200000) newsz = oldsz + (oldsz / 8);
	else if (oldsz < 400000) newsz = oldsz + (oldsz / 16);
	else if (oldsz < 800000) newsz = oldsz + (oldsz / 32);
	else if (oldsz < 1600000) newsz = oldsz + (oldsz / 64);
	else 
	{
		hcl_oow_t inc, inc_max;

		inc = oldsz / 128;
		inc_max = HCL_OBJ_SIZE_MAX - oldsz;
		if (inc > inc_max) 
		{
			if (inc_max > 0) inc = inc_max;
			else
			{
				hcl_seterrnum (hcl, HCL_EOOMEM);
				return HCL_NULL;
			}
		}
		newsz = oldsz + inc;
	}

	hcl_pushtmp (hcl, (hcl_oop_t*)&oldbuc);
	newbuc = (hcl_oop_oop_t)hcl_makearray (hcl, newsz, 0); 
	hcl_poptmp (hcl);
	if (!newbuc) return HCL_NULL;

	while (oldsz > 0)
	{
		ass = (hcl_oop_cons_t)oldbuc->slot[--oldsz];
		if ((hcl_oop_t)ass != hcl->_nil)
		{
		#if defined(SYMBOL_ONLY_KEY)
			HCL_ASSERT (hcl, HCL_IS_CONS(hcl,ass));
			key = (hcl_oop_char_t)ass->car;
			HCL_ASSERT (hcl, HCL_IS_SYMBOL(hcl,key));
			index = hcl_hashoochars(key->slot, HCL_OBJ_GET_SIZE(key)) % newsz;
		#else
			int n;
			HCL_ASSERT (hcl, HCL_IS_CONS(hcl,ass));
			n = hcl_hashobj(hcl, ass->car, &index);
			HCL_ASSERT (hcl, n == 0); /* since it's expanding, the existing in the bucket should always be hashable */
			index %= newsz;
		#endif
			while (newbuc->slot[index] != hcl->_nil) index = (index + 1) % newsz;
			newbuc->slot[index] = (hcl_oop_t)ass;
		}
	}

	return newbuc;
}

#if defined(SYMBOL_ONLY_KEY)
static hcl_oop_cons_t find_or_upsert (hcl_t* hcl, hcl_oop_dic_t dic, hcl_oop_char_t key, hcl_oop_t value)
#else
static hcl_oop_cons_t find_or_upsert (hcl_t* hcl, hcl_oop_dic_t dic, hcl_oop_t key, hcl_oop_t value)
#endif
{
	hcl_ooi_t tally;
	hcl_oow_t index;
	hcl_oop_cons_t ass;
	hcl_oow_t tmp_count = 0;

	/* the system dictionary is not a generic dictionary.
	 * it accepts only a symbol as a key. */
#if defined(SYMBOL_ONLY_KEY)
	HCL_ASSERT (hcl, HCL_IS_SYMBOL(hcl,key));
#endif
	HCL_ASSERT (hcl, HCL_OOP_IS_SMOOI(dic->tally));
	HCL_ASSERT (hcl, HCL_IS_ARRAY(hcl,dic->bucket));

#if defined(SYMBOL_ONLY_KEY)
	index = hcl_hashoochars(key->slot, HCL_OBJ_GET_SIZE(key)) % HCL_OBJ_GET_SIZE(dic->bucket);
#else
	if (hcl_hashobj(hcl, key, &index) <= -1) return HCL_NULL;
	index %= HCL_OBJ_GET_SIZE(dic->bucket);
#endif

	/* find */
	while (dic->bucket->slot[index] != hcl->_nil) 
	{
	#if defined(SYMBOL_ONLY_KEY)
		ass = (hcl_oop_cons_t)dic->bucket->slot[index];
		HCL_ASSERT (hcl, HCL_IS_CONS(hcl,ass));
		HCL_ASSERT (hcl, HCL_IS_SYMBOL(hcl,ass->car));

		if (HCL_OBJ_GET_SIZE(key) == HCL_OBJ_GET_SIZE(ass->car) &&
		    hcl_equal_oochars(key->slot, ((hcl_oop_char_t)ass->car)->slot, HCL_OBJ_GET_SIZE(key))) 
		{
			/* the value of HCL_NULL indicates no insertion or update. */
			if (value) ass->cdr = value; /* update */
			return ass;
		}
	#else
		int n;

		ass = (hcl_oop_cons_t)dic->bucket->slot[index];
		HCL_ASSERT (hcl, HCL_IS_CONS(hcl,ass));

		n = hcl_equalobjs(hcl, key, ass->car);
		if (n <= -1) return HCL_NULL;
		if (n >= 1)
		{
			/* the value of HCL_NULL indicates no insertion or update. */
			if (value) ass->cdr = value; /* update */
			return ass;
		}
	#endif

		index = (index + 1) % HCL_OBJ_GET_SIZE(dic->bucket);
	}

	if (!value)
	{
		/* when value is HCL_NULL, perform no insertion.
		 * the value of HCL_NULL indicates no insertion or update. */
		hcl_seterrbfmt (hcl, HCL_ENOENT, "key not found - %O", key);
		return HCL_NULL;
	}

	/* the key is not found. insert it. */
	HCL_ASSERT (hcl, HCL_OOP_IS_SMOOI(dic->tally));
	tally = HCL_OOP_TO_SMOOI(dic->tally);
	if (tally >= HCL_SMOOI_MAX)
	{
		/* this built-in dictionary is not allowed to hold more than 
		 * HCL_SMOOI_MAX items for efficiency sake */
		hcl_seterrnum (hcl, HCL_EDFULL);
		return HCL_NULL;
	}

	hcl_pushtmp (hcl, (hcl_oop_t*)&dic); tmp_count++;
	hcl_pushtmp (hcl, (hcl_oop_t*)&key); tmp_count++;
	hcl_pushtmp (hcl, &value); tmp_count++;

	/* no conversion to hcl_oow_t is necessary for tally + 1.
	 * the maximum value of tally is checked to be HCL_SMOOI_MAX - 1.
	 * tally + 1 can produce at most HCL_SMOOI_MAX. above all, 
	 * HCL_SMOOI_MAX is way smaller than HCL_TYPE_MAX(hcl_ooi_t). */
	if (tally + 1 >= HCL_OBJ_GET_SIZE(dic->bucket))
	{
		hcl_oop_oop_t bucket;

		/* TODO: make the growth policy configurable instead of growing
		         it just before it gets full. The polcy can be grow it
		         if it's 70% full */

		/* enlarge the bucket before it gets full to
		 * make sure that it has at least one free slot left
		 * after having added a new symbol. this is to help
		 * traversal end at a _nil slot if no entry is found. */
		bucket = expand_bucket (hcl, dic->bucket);
		if (!bucket) goto oops;

		dic->bucket = bucket;

	#if defined(SYMBOL_ONLY_KEY)
		/* recalculate the index for the expanded bucket */
		index = hcl_hashoochars(key->slot, HCL_OBJ_GET_SIZE(key)) % HCL_OBJ_GET_SIZE(dic->bucket);
	#else
		hcl_hashobj(hcl, key, &index); /* this must succeed as i know 'key' is hashable */
		index %= HCL_OBJ_GET_SIZE(dic->bucket);
	#endif

		while (dic->bucket->slot[index] != hcl->_nil) 
			index = (index + 1) % HCL_OBJ_GET_SIZE(dic->bucket);
	}

	/* create a new assocation of a key and a value since 
	 * the key isn't found in the root dictionary */
	ass = (hcl_oop_cons_t)hcl_makecons (hcl, (hcl_oop_t)key, value);
	if (!ass) goto oops;

	/* the current tally must be less than the maximum value. otherwise,
	 * it overflows after increment below */
	HCL_ASSERT (hcl, tally < HCL_SMOOI_MAX);
	dic->tally = HCL_SMOOI_TO_OOP(tally + 1);
	dic->bucket->slot[index] = (hcl_oop_t)ass;

	hcl_poptmps (hcl, tmp_count);
	return ass;

oops:
	hcl_poptmps (hcl, tmp_count);
	return HCL_NULL;
}

hcl_oop_cons_t hcl_putatsysdic (hcl_t* hcl, hcl_oop_t key, hcl_oop_t value)
{
#if defined(SYMBOL_ONLY_KEY)
	HCL_ASSERT (hcl, HCL_IS_SYMBOL(hcl,key));
#endif
	return find_or_upsert(hcl, hcl->sysdic, key, value);
}

hcl_oop_cons_t hcl_getatsysdic (hcl_t* hcl, hcl_oop_t key)
{
#if defined(SYMBOL_ONLY_KEY)
	HCL_ASSERT (hcl, HCL_IS_SYMBOL(hcl,key));
#endif
	return find_or_upsert(hcl, hcl->sysdic, key, HCL_NULL);
}

int hcl_zapatsysdic (hcl_t* hcl, hcl_oop_t key)
{
#if defined(SYMBOL_ONLY_KEY)
	HCL_ASSERT (hcl, HCL_IS_SYMBOL(hcl,key));
#endif
	return hcl_zapatdic(hcl, hcl->sysdic, key);
}

hcl_oop_cons_t hcl_putatdic (hcl_t* hcl, hcl_oop_dic_t dic, hcl_oop_t key, hcl_oop_t value)
{
#if defined(SYMBOL_ONLY_KEY)
	HCL_ASSERT (hcl, HCL_IS_SYMBOL(hcl,key));
#endif
	return find_or_upsert(hcl, dic, key, value);
}

hcl_oop_cons_t hcl_getatdic (hcl_t* hcl, hcl_oop_dic_t dic, hcl_oop_t key)
{
#if defined(SYMBOL_ONLY_KEY)
	HCL_ASSERT (hcl, HCL_IS_SYMBOL(hcl,key));
#endif
	return find_or_upsert(hcl, dic, key, HCL_NULL);
}

int hcl_zapatdic (hcl_t* hcl, hcl_oop_dic_t dic, hcl_oop_t key)
{
	hcl_ooi_t tally;
	hcl_oow_t index, bs, i, x, y, z;
	hcl_oop_cons_t ass;

	tally = HCL_OOP_TO_SMOOI(dic->tally);
	bs = HCL_OBJ_GET_SIZE(dic->bucket);

	/* the system dictionary is not a generic dictionary.
	 * it accepts only a symbol as a key. */
#if defined(SYMBOL_ONLY_KEY)
	HCL_ASSERT (hcl, HCL_IS_SYMBOL(hcl,key));
#endif
	HCL_ASSERT (hcl, HCL_OOP_IS_SMOOI(dic->tally));
	HCL_ASSERT (hcl, HCL_IS_ARRAY(hcl,dic->bucket));

#if defined(SYMBOL_ONLY_KEY)
	index = hcl_hashoochars(key->slot, HCL_OBJ_GET_SIZE(key)) % bs;
#else
	if (hcl_hashobj(hcl, key, &index) <= -1) return -1;
	index %= bs;
#endif

	/* find */
	while (dic->bucket->slot[index] != hcl->_nil) 
	{
	#if defined(SYMBOL_ONLY_KEY)
		ass = (hcl_oop_cons_t)dic->bucket->slot[index];
		HCL_ASSERT (hcl, HCL_IS_CONS(hcl,ass));
		HCL_ASSERT (hcl, HCL_IS_SYMBOL(hcl,ass->car));

		if (HCL_OBJ_GET_SIZE(key) == HCL_OBJ_GET_SIZE(ass->car) &&
		    hcl_equal_oochars(HCL_OBJ_GET_CHAR_SLOT(key), HCL_OBJ_GET_CHAR_SLOT(ass->car), HCL_OBJ_GET_SIZE(key))) 
		{
			/* the value of HCL_NULL indicates no insertion or update. */
			goto found;
		}
	#else
		int n;

		ass = (hcl_oop_cons_t)dic->bucket->slot[index];
		HCL_ASSERT (hcl, HCL_IS_CONS(hcl,ass));

		n = hcl_equalobjs(hcl, (hcl_oop_t)key, ass->car);
		if (n <= -1) return -1;
		if (n >= 1) goto found;
	#endif

		index = (index + 1) % bs;
	}

	hcl_seterrnum (hcl, HCL_ENOENT);
	return -1;

found:
	/* compact the cluster */
	for (i = 0, x = index, y = index; i < tally; i++)
	{
		y = (y + 1) % bs;

		/* done if the slot at the current index is empty */
		if (dic->bucket->slot[y] == hcl->_nil) break;

		ass = (hcl_oop_cons_t)dic->bucket->slot[y];
	#if defined(SYMBOL_ONLY_KEY)
		/* get the natural hash index for the data in the slot at
		 * the current hash index */
		z = hcl_hashoochars(HCL_OBJ_GET_CHAR_SLOT(ass->car), HCL_OBJ_GET_SIZE(ass->car)) % bs;
	#else
		if (hcl_hashobj(hcl, ass->car, &z) <= -1) return -1;
		z %= bs;
	#endif

		/* move an element if necesary */
		if ((y > x && (z <= x || z > y)) ||
		    (y < x && (z <= x && z > y)))
		{
			dic->bucket->slot[x] = dic->bucket->slot[y];
			x = y;
		}
	}

	dic->bucket->slot[x] = hcl->_nil;

	tally--;
	dic->tally = HCL_SMOOI_TO_OOP(tally);

	return 0;
}

hcl_oop_t hcl_makedic (hcl_t* hcl, hcl_oow_t inisize)
{
	hcl_oop_dic_t obj;

	obj = (hcl_oop_dic_t)hcl_allocoopobj (hcl, HCL_BRAND_DIC, 2);
	if (obj)
	{
		hcl_oop_oop_t bucket;

		obj->tally = HCL_SMOOI_TO_OOP(0);

		hcl_pushtmp (hcl, (hcl_oop_t*)&obj);
		bucket = (hcl_oop_oop_t)hcl_makearray(hcl, inisize, 0);
		hcl_poptmp (hcl);

		if (!bucket) obj = HCL_NULL;
		else obj->bucket = bucket;
	}

	return (hcl_oop_t)obj;
}

int hcl_walkdic (hcl_t* hcl, hcl_oop_dic_t dic, hcl_dic_walker_t walker, void* ctx)
{
	hcl_oow_t i;

	hcl_pushtmp (hcl, (hcl_oop_t*)&dic);

	for (i = 0; i < HCL_OBJ_GET_SIZE(dic->bucket); i++)
	{
		hcl_oop_t tmp = dic->bucket->slot[i];
		if (HCL_IS_CONS(hcl, tmp) && walker(hcl, dic, (hcl_oop_cons_t)tmp, ctx) <= -1) return -1;
	}

	hcl_poptmp (hcl);
	return 0;
}