/*****************************************************************************

Copyright (c) 2013, 2015, Oracle and/or its affiliates. All Rights Reserved.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License, version 2.0,
as published by the Free Software Foundation.

This program is also distributed with certain software (including
but not limited to OpenSSL) that is licensed under separate terms,
as designated in a particular file or component or in included license
documentation.  The authors of MySQL hereby grant you an additional
permission to link the program and your derivative works with the
separately licensed software that they have included with MySQL.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License, version 2.0, for more details.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA

*****************************************************************************/

/**************************************************//**
@file gis/gis0geo.cc
InnoDB R-tree related functions.

Created 2013/03/27 Allen Lai and Jimmy Yang
*******************************************************/

#include "page0types.h"
#include "gis0geo.h"
#include "page0cur.h"
#include "ut0rnd.h"
#include "mach0data.h"

#include <spatial.h>

/* These definitions are for comparing 2 mbrs. */

/* Check if a intersects b.
Return false if a intersects b, otherwise true. */
#define INTERSECT_CMP(amin, amax, bmin, bmax) \
(((amin) > (bmax)) || ((bmin) > (amax)))

/* Check if b contains a.
Return false if b contains a, otherwise true. */
#define CONTAIN_CMP(amin, amax, bmin, bmax) \
(((bmin) > (amin)) || ((bmax) < (amax)))

/* Check if b is within a.
Return false if b is within a, otherwise true. */
#define WITHIN_CMP(amin, amax, bmin, bmax) \
(((amin) > (bmin)) || ((amax) < (bmax)))

/* Check if a disjoints b.
Return false if a disjoints b, otherwise true. */
#define DISJOINT_CMP(amin, amax, bmin, bmax) \
(((amin) <= (bmax)) && ((bmin) <= (amax)))

/* Check if a equals b.
Return false if equal, otherwise true. */
#define EQUAL_CMP(amin, amax, bmin, bmax) \
(((amin) != (bmin)) || ((amax) != (bmax)))

/****************************************************************
Functions for generating mbr
****************************************************************/
/*************************************************************//**
Add one point stored in wkb to a given mbr.
@return 0 if the point in wkb is valid, otherwise -1. */
static
int
rtree_add_point_to_mbr(
/*===================*/
	uchar**	wkb,		/*!< in: pointer to wkb,
				where point is stored */
	uchar*	end,		/*!< in: end of wkb. */
	uint	n_dims,		/*!< in: dimensions. */
	uchar	byte_order,	/*!< in: byte order. */
	double*	mbr)		/*!< in/out: mbr, which
				must be of length n_dims * 2. */
{
	double	ord;
	double*	mbr_end = mbr + n_dims * 2;

	while (mbr < mbr_end) {
		if ((*wkb) + sizeof(double) > end) {
			return(-1);
		}

		ord = mach_double_read(*wkb);
		(*wkb) += sizeof(double);

		if (ord < *mbr) {
			*mbr = ord;
		}
		mbr++;

		if (ord > *mbr) {
			*mbr = ord;
		}
		mbr++;
	}

	return(0);
}

/*************************************************************//**
Get mbr of point stored in wkb.
@return 0 if ok, otherwise -1. */
static
int
rtree_get_point_mbr(
/*================*/
	uchar**	wkb,		/*!< in: pointer to wkb,
				where point is stored. */
	uchar*	end,		/*!< in: end of wkb. */
	uint	n_dims,		/*!< in: dimensions. */
	uchar	byte_order,	/*!< in: byte order. */
	double*	mbr)		/*!< in/out: mbr,
				must be of length n_dims * 2. */
{
	return rtree_add_point_to_mbr(wkb, end, n_dims, byte_order, mbr);
}


/*************************************************************//**
Get mbr of linestring stored in wkb.
@return 0 if the linestring is valid, otherwise -1. */
static
int
rtree_get_linestring_mbr(
/*=====================*/
	uchar**	wkb,		/*!< in: pointer to wkb,
				where point is stored. */
	uchar*	end,		/*!< in: end of wkb. */
	uint	n_dims,		/*!< in: dimensions. */
	uchar	byte_order,	/*!< in: byte order. */
	double*	mbr)		/*!< in/out: mbr,
				must be of length n_dims * 2. */
{
	uint	n_points;

	n_points = uint4korr(*wkb);
	(*wkb) += 4;

	for (; n_points > 0; --n_points) {
		/* Add next point to mbr */
		if (rtree_add_point_to_mbr(wkb, end, n_dims,
					   byte_order, mbr)) {
			return(-1);
		}
	}

	return(0);
}

/*************************************************************//**
Get mbr of polygon stored in wkb.
@return 0 if the polygon is valid, otherwise -1. */
static
int
rtree_get_polygon_mbr(
/*==================*/
	uchar**	wkb,		/*!< in: pointer to wkb,
				where point is stored. */
	uchar*	end,		/*!< in: end of wkb. */
	uint	n_dims,		/*!< in: dimensions. */
	uchar	byte_order,	/*!< in: byte order. */
	double*	mbr)		/*!< in/out: mbr,
				must be of length n_dims * 2. */
{
	uint	n_linear_rings;
	uint	n_points;

	n_linear_rings = uint4korr((*wkb));
	(*wkb) += 4;

	for (; n_linear_rings > 0; --n_linear_rings) {
		n_points = uint4korr((*wkb));
		(*wkb) += 4;

		for (; n_points > 0; --n_points) {
			/* Add next point to mbr */
			if (rtree_add_point_to_mbr(wkb, end, n_dims,
						   byte_order, mbr)) {
				return(-1);
			}
		}
	}

	return(0);
}

/*************************************************************//**
Get mbr of geometry stored in wkb.
@return 0 if the geometry is valid, otherwise -1. */
static
int
rtree_get_geometry_mbr(
/*===================*/
	uchar**	wkb,		/*!< in: pointer to wkb,
				where point is stored. */
	uchar*	end,		/*!< in: end of wkb. */
	uint	n_dims,		/*!< in: dimensions. */
	double*	mbr,		/*!< in/out: mbr. */
	int	top)		/*!< in: if it is the top,
				which means it's not called
				by itself. */
{
	int	res;
	uchar	byte_order = 2;
	uint	wkb_type = 0;
	uint	n_items;

	byte_order = *(*wkb);
	++(*wkb);

	wkb_type = uint4korr((*wkb));
	(*wkb) += 4;

	switch ((enum wkbType) wkb_type) {
	case wkbPoint:
		res = rtree_get_point_mbr(wkb, end, n_dims, byte_order, mbr);
		break;
	case wkbLineString:
		res = rtree_get_linestring_mbr(wkb, end, n_dims,
					       byte_order, mbr);
		break;
	case wkbPolygon:
		res = rtree_get_polygon_mbr(wkb, end, n_dims, byte_order, mbr);
		break;
	case wkbMultiPoint:
		n_items = uint4korr((*wkb));
		(*wkb) += 4;
		for (; n_items > 0; --n_items) {
			byte_order = *(*wkb);
			++(*wkb);
			(*wkb) += 4;
			if (rtree_get_point_mbr(wkb, end, n_dims,
						byte_order, mbr)) {
				return(-1);
			}
		}
		res = 0;
		break;
	case wkbMultiLineString:
		n_items = uint4korr((*wkb));
		(*wkb) += 4;
		for (; n_items > 0; --n_items) {
			byte_order = *(*wkb);
			++(*wkb);
			(*wkb) += 4;
			if (rtree_get_linestring_mbr(wkb, end, n_dims,
						     byte_order, mbr)) {
				return(-1);
			}
		}
		res = 0;
		break;
	case wkbMultiPolygon:
		n_items = uint4korr((*wkb));
		(*wkb) += 4;
		for (; n_items > 0; --n_items) {
			byte_order = *(*wkb);
			++(*wkb);
			(*wkb) += 4;
			if (rtree_get_polygon_mbr(wkb, end, n_dims,
						  byte_order, mbr)) {
				return(-1);
			}
		}
		res = 0;
		break;
	case wkbGeometryCollection:
		if (!top) {
			return(-1);
		}

		n_items = uint4korr((*wkb));
		(*wkb) += 4;
		for (; n_items > 0; --n_items) {
			if (rtree_get_geometry_mbr(wkb, end, n_dims,
						   mbr, 0)) {
				return(-1);
			}
		}
		res = 0;
		break;
	default:
		res = -1;
	}

	return(res);
}

/*************************************************************//**
Calculate Minimal Bounding Rectangle (MBR) of the spatial object
stored in "well-known binary representation" (wkb) format.
@return 0 if ok. */
int
rtree_mbr_from_wkb(
/*===============*/
	uchar*	wkb,		/*!< in: wkb */
	uint	size,		/*!< in: size of wkb. */
	uint	n_dims,		/*!< in: dimensions. */
	double*	mbr)		/*!< in/out: mbr, which must
				be of length n_dim2 * 2. */
{
	for (uint i = 0; i < n_dims; ++i) {
		mbr[i * 2] = DBL_MAX;
		mbr[i * 2 + 1] = -DBL_MAX;
	}

	return rtree_get_geometry_mbr(&wkb, wkb + size, n_dims, mbr, 1);
}


/****************************************************************
Functions for Rtree split
****************************************************************/
/*************************************************************//**
Join 2 mbrs of dimensions n_dim. */
static
void
mbr_join(
/*=====*/
	double*		a,	/*!< in/out: the first mbr,
				where the joined result will be. */
	const double*	b,	/*!< in: the second mbr. */
	int		n_dim)	/*!< in: dimensions. */
{
	double*		end = a + n_dim * 2;

	do {
		if (a[0] > b[0]) {
			a[0] = b[0];
		}

		if (a[1] < b[1]) {
			a[1] = b[1];
		}

		a += 2;
		b += 2;

	} while (a != end);
}

/*************************************************************//**
Counts the square of mbr which is the join of a and b. Both a and b
are of dimensions n_dim. */
static
double
mbr_join_square(
/*============*/
	const double*	a,	/*!< in: the first mbr. */
	const double*	b,	/*!< in: the second mbr. */
	int		n_dim)	/*!< in: dimensions. */
{
	const double*	end = a + n_dim * 2;
	double		square = 1.0;

	do {
		square *= std::max(a[1], b[1]) - std::min(a[0], b[0]);

		a += 2;
		b += 2;
	} while (a != end);

	/* Check for infinity or NaN, so we don't get NaN in calculations */
	if (my_isinf(square) || my_isnan(square)) {
		return DBL_MAX;
	}

	return square;
}

/*************************************************************//**
Counts the square of mbr of dimension n_dim. */
static
double
count_square(
/*=========*/
	const double*	a,	/*!< in: the mbr. */
	int		n_dim)	/*!< in: dimensions. */
{
	const double*	end = a + n_dim * 2;
	double		square = 1.0;

	do {
		square *= a[1] - a[0];
		a += 2;
	} while (a != end);

	return square;
}

/*************************************************************//**
Copy mbr of dimension n_dim from src to dst. */
inline
static
void
copy_coords(
/*========*/
	double*		dst,	/*!< in/out: destination. */
	const double*	src,	/*!< in: source. */
	int		n_dim)	/*!< in: dimensions. */
{
	memcpy(dst, src, DATA_MBR_LEN);
}

/*************************************************************//**
Select two nodes to collect group upon */
static
void
pick_seeds(
/*=======*/
	rtr_split_node_t*	node,		/*!< in: split nodes. */
	int			n_entries,	/*!< in: entries number. */
	rtr_split_node_t**	seed_a,		/*!< out: seed 1. */
	rtr_split_node_t**	seed_b,		/*!< out: seed 2. */
	int			n_dim)		/*!< in: dimensions. */
{
	rtr_split_node_t*	cur1;
	rtr_split_node_t*	lim1 = node + (n_entries - 1);
	rtr_split_node_t*	cur2;
	rtr_split_node_t*	lim2 = node + n_entries;

	double			max_d = -DBL_MAX;
	double			d;

	*seed_a = node;
	*seed_b = node + 1;

	for (cur1 = node; cur1 < lim1; ++cur1) {
		for (cur2 = cur1 + 1; cur2 < lim2; ++cur2) {
			d = mbr_join_square(cur1->coords, cur2->coords, n_dim) -
				cur1->square - cur2->square;
			if (d > max_d) {
				max_d = d;
				*seed_a = cur1;
				*seed_b = cur2;
			}
		}
	}
}

/*********************************************************//**
Generates a random iboolean value.
@return the random value */
static
ibool
ut_rnd_gen_ibool(void)
/*=================*/
{
	ulint    x;

	x = ut_rnd_gen_ulint();

	if (((x >> 20) + (x >> 15)) & 1) {

		return(TRUE);
	}

	return(FALSE);
}

/*************************************************************//**
Select next node and group where to add. */
static
void
pick_next(
/*======*/
	rtr_split_node_t*	node,		/*!< in: split nodes. */
	int			n_entries,	/*!< in: entries number. */
	double*			g1,		/*!< in: mbr of group 1. */
	double*			g2,		/*!< in: mbr of group 2. */
	rtr_split_node_t**	choice,		/*!< out: the next node.*/
	int*			n_group,	/*!< out: group number.*/
	int			n_dim)		/*!< in: dimensions. */
{
	rtr_split_node_t*	cur = node;
	rtr_split_node_t*	end = node + n_entries;
	double			max_diff = -DBL_MAX;

	for (; cur < end; ++cur) {
		double	diff;
		double	abs_diff;

		if (cur->n_node != 0) {
			continue;
		}

		diff = mbr_join_square(g1, cur->coords, n_dim) -
		       mbr_join_square(g2, cur->coords, n_dim);

		abs_diff = fabs(diff);
		if (abs_diff > max_diff) {
			max_diff = abs_diff;

			/* Introduce some randomness if the record
			is identical */
			if (diff == 0) {
				diff = static_cast<double>(
					ut_rnd_gen_ibool());
			}

			*n_group = 1 + (diff > 0);
			*choice = cur;
		}
	}
}

/*************************************************************//**
Mark not-in-group entries as n_group. */
static
void
mark_all_entries(
/*=============*/
	rtr_split_node_t*	node,		/*!< in/out: split nodes. */
	int			n_entries,	/*!< in: entries number. */
	int			n_group)	/*!< in: group number. */
{
	rtr_split_node_t*	cur = node;
	rtr_split_node_t*	end = node + n_entries;
	for (; cur < end; ++cur) {
		if (cur->n_node != 0) {
			continue;
		}
		cur->n_node = n_group;
	}
}

/*************************************************************//**
Split rtree node.
Return which group the first rec is in. */
int
split_rtree_node(
/*=============*/
	rtr_split_node_t*	node,		/*!< in: split nodes. */
	int			n_entries,	/*!< in: entries number. */
	int			all_size,	/*!< in: total key's size. */
	int			key_size,	/*!< in: key's size. */
	int			min_size,	/*!< in: minimal group size. */
	int			size1,		/*!< in: size of group. */
	int			size2,		/*!< in: initial group sizes */
	double**		d_buffer,	/*!< in/out: buffer. */
	int			n_dim,		/*!< in: dimensions. */
	uchar*			first_rec)	/*!< in: the first rec. */
{
	rtr_split_node_t*	cur;
	rtr_split_node_t*	a = NULL;
	rtr_split_node_t*	b = NULL;
	double*			g1 = reserve_coords(d_buffer, n_dim);
	double*			g2 = reserve_coords(d_buffer, n_dim);
	rtr_split_node_t*	next = NULL;
	int			next_node = 0;
	int			i;
	int			first_rec_group = 1;
	rtr_split_node_t*	end = node + n_entries;

	if (all_size < min_size * 2) {
		return 1;
	}

	cur = node;
	for (; cur < end; ++cur) {
		cur->square = count_square(cur->coords, n_dim);
		cur->n_node = 0;
	}

	pick_seeds(node, n_entries, &a, &b, n_dim);
	a->n_node = 1;
	b->n_node = 2;

	copy_coords(g1, a->coords, n_dim);
	size1 += key_size;
	copy_coords(g2, b->coords, n_dim);
	size2 += key_size;

	for (i = n_entries - 2; i > 0; --i) {
		/* Can't write into group 2 */
		if (all_size - (size2 + key_size) < min_size) {
			mark_all_entries(node, n_entries, 1);
			break;
		}

		/* Can't write into group 1 */
		if (all_size - (size1 + key_size) < min_size) {
			mark_all_entries(node, n_entries, 2);
			break;
		}

		pick_next(node, n_entries, g1, g2, &next, &next_node, n_dim);
		if (next_node == 1) {
			size1 += key_size;
			mbr_join(g1, next->coords, n_dim);
		} else {
			size2 += key_size;
			mbr_join(g2, next->coords, n_dim);
		}

		next->n_node = next_node;

		/* Find out where the first rec (of the page) will be at,
		and inform the caller */
		if (first_rec && first_rec == next->key) {
			first_rec_group = next_node;
		}
	}

	return(first_rec_group);
}

/*************************************************************//**
Compares two keys a and b depending on nextflag
nextflag can contain these flags:
   MBR_INTERSECT(a,b)  a overlaps b
   MBR_CONTAIN(a,b)    a contains b
   MBR_DISJOINT(a,b)   a disjoint b
   MBR_WITHIN(a,b)     a within   b
   MBR_EQUAL(a,b)      All coordinates of MBRs are equal
Return 0 on success, otherwise 1. */
int
rtree_key_cmp(
/*==========*/
	page_cur_mode_t	mode,	/*!< in: compare method. */
	const uchar*	b,	/*!< in: first key. */
	int		b_len,	/*!< in: first key len. */
	const uchar*	a,	/*!< in: second key. */
	int		a_len)	/*!< in: second key len. */
{
	double		amin, amax, bmin, bmax;
	int		key_len;
	int		keyseg_len;

	keyseg_len = 2 * sizeof(double);
	for (key_len = a_len; key_len > 0; key_len -= keyseg_len) {
		amin = mach_double_read(a);
		bmin = mach_double_read(b);
		amax = mach_double_read(a + sizeof(double));
		bmax = mach_double_read(b + sizeof(double));

		switch (mode) {
		case PAGE_CUR_INTERSECT:
			if (INTERSECT_CMP(amin, amax, bmin, bmax)) {
				return(1);
			}
			break;
		case PAGE_CUR_CONTAIN:
			if (CONTAIN_CMP(amin, amax, bmin, bmax)) {
				return(1);
			}
			break;
		case PAGE_CUR_WITHIN:
			if (WITHIN_CMP(amin, amax, bmin, bmax)) {
				return(1);
			}
			break;
		case PAGE_CUR_MBR_EQUAL:
			if (EQUAL_CMP(amin, amax, bmin, bmax)) {
				return(1);
			}
			break;
		case PAGE_CUR_DISJOINT:
			int result;

			result = DISJOINT_CMP(amin, amax, bmin, bmax);
			if (result == 0) {
				return(0);
			}

			if (key_len - keyseg_len <= 0) {
				return(1);
			}

			break;
		default:
			/* if unknown comparison operator */
			ut_ad(0);
		}

		a += keyseg_len;
		b += keyseg_len;
	}

	return(0);
}

/*************************************************************//**
Calculates MBR_AREA(a+b) - MBR_AREA(a)
Note: when 'a' and 'b' objects are far from each other,
the area increase can be really big, so this function
can return 'inf' as a result.
Return the area increaed. */
double
rtree_area_increase(
	const uchar*	a,		/*!< in: original mbr. */
	const uchar*	b,		/*!< in: new mbr. */
	int		mbr_len,	/*!< in: mbr length of a and b. */
	double*		ab_area)	/*!< out: increased area. */
{
	double		a_area = 1.0;
	double		loc_ab_area = 1.0;
	double		amin, amax, bmin, bmax;
	int		key_len;
	int		keyseg_len;
	double		data_round = 1.0;

	keyseg_len = 2 * sizeof(double);

	for (key_len = mbr_len; key_len > 0; key_len -= keyseg_len) {
		double	area;

		amin = mach_double_read(a);
		bmin = mach_double_read(b);
		amax = mach_double_read(a + sizeof(double));
		bmax = mach_double_read(b + sizeof(double));

		area = amax - amin;
		if (area == 0) {
			a_area *= LINE_MBR_WEIGHTS;
		} else {
			a_area *= area;
		}

		area = (double)std::max(amax, bmax) -
		       (double)std::min(amin, bmin);
		if (area == 0) {
			loc_ab_area *= LINE_MBR_WEIGHTS;
		} else {
			loc_ab_area *= area;
		}

		/* Value of amax or bmin can be so large that small difference
		are ignored. For example: 3.2884281489988079e+284 - 100 =
		3.2884281489988079e+284. This results some area difference
		are not detected */
		if (loc_ab_area == a_area) {
			if (bmin < amin || bmax > amax) {
				data_round *= ((double)std::max(amax, bmax)
					       - amax
					       + (amin - (double)std::min(
								amin, bmin)));
			} else {
				data_round *= area;
			}
		}

		a += keyseg_len;
		b += keyseg_len;
	}

	*ab_area = loc_ab_area;

	if (loc_ab_area == a_area && data_round != 1.0) {
		return(data_round);
	}

	return(loc_ab_area - a_area);
}

/** Calculates overlapping area
@param[in]	a	mbr a
@param[in]	b	mbr b
@param[in]	mbr_len	mbr length
@return overlapping area */
double
rtree_area_overlapping(
	const uchar*	a,
	const uchar*	b,
	int		mbr_len)
{
	double	area = 1.0;
	double	amin;
	double	amax;
	double	bmin;
	double	bmax;
	int	key_len;
	int	keyseg_len;

	keyseg_len = 2 * sizeof(double);

	for (key_len = mbr_len; key_len > 0; key_len -= keyseg_len) {
		amin = mach_double_read(a);
		bmin = mach_double_read(b);
		amax = mach_double_read(a + sizeof(double));
		bmax = mach_double_read(b + sizeof(double));

		amin = std::max(amin, bmin);
		amax = std::min(amax, bmax);

		if (amin > amax) {
			return(0);
		} else {
			area *= (amax - amin);
		}

		a += keyseg_len;
		b += keyseg_len;
	}

	return(area);
}

/** Get the wkb of default POINT value, which represents POINT(0 0)
if it's of dimension 2, etc.
@param[in]	n_dims		dimensions
@param[out]	wkb		wkb buffer for default POINT
@param[in]	len		length of wkb buffer
@return non-0 indicate the length of wkb of the default POINT,
0 if the buffer is too small */
uint
get_wkb_of_default_point(
	uint	n_dims,
	uchar*	wkb,
	uint	len)
{
	if (len < GEOM_HEADER_SIZE + sizeof(double) * n_dims) {
		return(0);
	}

	/** POINT wkb comprises SRID, wkb header(byte order and type)
	and coordinates of the POINT */
	len = GEOM_HEADER_SIZE + sizeof(double) * n_dims;
	/** We always use 0 as default coordinate */
	memset(wkb, 0, len);
	/** We don't need to write SRID, write 0x01 for Byte Order */
	mach_write_to_n_little_endian(wkb + SRID_SIZE, 1, 0x01);
	/** Write wkbType::wkbPoint for the POINT type */
	mach_write_to_n_little_endian(wkb + SRID_SIZE + 1, 4, wkbPoint);

	return(len);
}
