//
//  RMFractalTileProjection.m
//
// Copyright (c) 2008-2009, Route-Me Contributors
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice, this
//   list of conditions and the following disclaimer.
// * 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 COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR CONTRIBUTORS 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.

#import "RMFractalTileProjection.h"

#import <math.h>

@implementation RMFractalTileProjection

@synthesize maxZoom, minZoom;
@synthesize tileSideLength;
@synthesize planetBounds;

- (id)initFromProjection:(RMProjection *)projection tileSideLength:(NSUInteger)aTileSideLength maxZoom:(NSUInteger)aMaxZoom minZoom:(NSUInteger)aMinZoom
{
	if (!(self = [super init]))
		return nil;

	// We don't care about the rest of the projection... just the bounds is important.
	planetBounds = [projection planetBounds];

	if (planetBounds.size.width == 0.0f || planetBounds.size.height == 0.0f)
	{
		@throw [NSException exceptionWithName:@"RMUnknownBoundsException"
									   reason:@"RMFractalTileProjection was initialised with a projection with unknown bounds"
									 userInfo:nil];
	}

	tileSideLength = aTileSideLength;
	maxZoom = aMaxZoom;
	minZoom = aMinZoom;

	scaleFactor = log2(planetBounds.size.width / tileSideLength);

	return self;
}

- (void)setTileSideLength:(NSUInteger)aTileSideLength
{
	tileSideLength = aTileSideLength;

	scaleFactor = log2(planetBounds.size.width / tileSideLength);
}

- (void)setMinZoom:(NSUInteger)aMinZoom
{
	minZoom = aMinZoom;
}

- (void)setMaxZoom:(NSUInteger)aMaxZoom
{
	maxZoom = aMaxZoom;
}

- (float)normaliseZoom:(float)zoom
{
	float normalised_zoom = roundf(zoom);

	if (normalised_zoom > maxZoom)
		normalised_zoom = maxZoom;
	if (normalised_zoom < minZoom)
		normalised_zoom = minZoom;

	return normalised_zoom;
}

- (float)limitFromNormalisedZoom:(float)zoom
{
	return exp2f(zoom);
}

- (RMTile)normaliseTile:(RMTile)tile
{
	// The mask contains a 1 for every valid x-coordinate bit.
	uint32_t mask = 1;

	for (int i = 0; i < tile.zoom; i++)
		mask <<= 1;

	mask -= 1;
	tile.x &= mask;

	// If the tile's y coordinate is off the screen
	if (tile.y & (~mask))
		return RMTileDummy();

	return tile;
}

- (RMProjectedPoint)constrainPointHorizontally:(RMProjectedPoint)aPoint
{
	while (aPoint.x < planetBounds.origin.x)
		aPoint.x += planetBounds.size.width;

	while (aPoint.x > (planetBounds.origin.x + planetBounds.size.width))
		aPoint.x -= planetBounds.size.width;

	return aPoint;
}

- (RMTilePoint)projectInternal:(RMProjectedPoint)aPoint normalisedZoom:(float)zoom limit:(float)limit
{
	RMTilePoint tile;
	RMProjectedPoint newPoint = [self constrainPointHorizontally:aPoint];

	double x = (newPoint.x - planetBounds.origin.x) / planetBounds.size.width * limit;
    
	// Unfortunately, y is indexed from the bottom left.. hence we have to translate it.
	double y = (double)limit * ((planetBounds.origin.y - newPoint.y) / planetBounds.size.height + 1);

	tile.tile.x = (uint32_t)x;
	tile.tile.y = (uint32_t)y;
	tile.tile.zoom = zoom;
	tile.offset.x = (float)x - tile.tile.x;
	tile.offset.y = (float)y - tile.tile.y;

	return tile;
}

- (RMTilePoint)project:(RMProjectedPoint)aPoint atZoom:(float)zoom
{
	float normalised_zoom = [self normaliseZoom:zoom];
	float limit = [self limitFromNormalisedZoom:normalised_zoom];

	return [self projectInternal:aPoint normalisedZoom:normalised_zoom limit:limit];
}

- (RMTileRect)projectRect:(RMProjectedRect)aRect atZoom:(float)zoom
{
	float normalised_zoom = [self normaliseZoom:zoom];
	float limit = [self limitFromNormalisedZoom:normalised_zoom];

	RMTileRect tileRect;
	// The origin for projectInternal will have to be the top left instead of the bottom left.
	RMProjectedPoint topLeft = aRect.origin;
	topLeft.y += aRect.size.height;
	tileRect.origin = [self projectInternal:topLeft normalisedZoom:normalised_zoom limit:limit];

	tileRect.size.width = aRect.size.width / planetBounds.size.width * limit;
	tileRect.size.height = aRect.size.height / planetBounds.size.height * limit;

	return tileRect;
}

- (RMTilePoint)project:(RMProjectedPoint)aPoint atScale:(float)scale
{
	return [self project:aPoint atZoom:[self calculateZoomFromScale:scale]];
}

- (RMTileRect)projectRect:(RMProjectedRect)aRect atScale:(float)scale
{
	return [self projectRect:aRect atZoom:[self calculateZoomFromScale:scale]];
}

- (float)calculateZoomFromScale:(float)scale
{
    // zoom = log2(bounds.width/tileSideLength) - log2(s)
	return scaleFactor - log2(scale);
}

- (float)calculateNormalisedZoomFromScale:(float)scale
{
	return [self normaliseZoom:[self calculateZoomFromScale:scale]];
}

- (float)calculateScaleFromZoom:(float)zoom
{
	return planetBounds.size.width / tileSideLength / exp2(zoom);
}

@end