/*
 * Copyright (C)2005-2012 Haxe Foundation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */
package cs.internal;

@:native('haxe.lang.FieldLookup')
@:final @:nativeGen
@:keep @:static class FieldLookup
{

	@:private private static var fieldIds:Array<Int>;
	@:private private static var fields:Array<String>;

	//s cannot be null here
	private static inline function doHash(s:String):Int
	{
		var acc = 0; //alloc_int
		for (i in 0...s.length)
		{
			acc = (( 223 * (acc >> 1) + cast(s[i], Int)) << 1);
		}

		return acc >>> 1; //always positive
	}

	public static function lookupHash(key:Int):String
	{
		//start of binary search algorithm
		var ids = fieldIds;
		var min = 0;
		var max = ids.length;

		while (min < max)
		{
			var mid = min + Std.int((max - min) / 2);
			var imid = ids[mid];
			if (key < imid)
			{
				max = mid;
			} else if (key > imid) {
				min = mid + 1;
			} else {
				return fields[mid];
			}
		}
		//if not found, it's definately an error
		throw "Field not found for hash " + key;
	}

	public static function hash(s:String):Int
	{
		if (s == null) return 0;

		var key = doHash(s);

		//start of binary search algorithm
		var ids = fieldIds;
		var min = 0;
		var max = ids.length;

		while (min < max)
		{
			var mid = Std.int(min + (max - min) / 2); //overflow safe
			var imid = ids[mid];
			if (key < imid)
			{
				max = mid;
			} else if (key > imid) {
				min = mid + 1;
			} else {
				var field = fields[mid];
				if (field != s)
					return ~key; //special case
				return key;
			}
		}
		//if not found, min holds the value where we should insert the key
		ids.insert(min, key);
		fields.insert(min, s);
		return key;
	}

	public static function findHash(hash:Int, hashs:cs.NativeArray<Int>, length:Int):Int
	{
		var min = 0;
		var max = length;

		while (min < max)
		{
			var mid = Std.int((max + min) / 2); //overflow safe
			var imid = hashs[mid];
			if (hash < imid)
			{
				max = mid;
			} else if (hash > imid) {
				min = mid + 1;
			} else {
				return mid;
			}
		}
		//if not found, return a negative value of where it should be inserted
		return ~min;
	}

	#if !erase_generics
	static function remove<T>(a:cs.NativeArray<T>, length:Int, pos:Int)
	{
		cs.system.Array.Copy(a, pos + 1, a, pos, length - pos - 1);
		a[length - 1] = null;
	}

	static function insert<T>(a:cs.Ref<cs.NativeArray<T>>, length:Int, pos:Int, x:T)
	{
		var capacity = a.Length;
		if (pos == length)
		{
			if (capacity == length)
			{
				var newarr = new NativeArray((length << 1) + 1);
				a.CopyTo(newarr, 0);
				a = newarr;
			}
		}
		else if (pos == 0)
		{
			if (capacity == length)
			{
				var newarr = new NativeArray((length << 1) + 1);
				cs.system.Array.Copy(a, 0, newarr, 1, length);
				a = newarr;
			}
			else
			{
				cs.system.Array.Copy(a, 0, a, 1, length);
			}
		}
		else
		{
			if (capacity == length)
			{
				var newarr = new NativeArray((length << 1) + 1);
				cs.system.Array.Copy(a, 0, newarr, 0, pos);
				cs.system.Array.Copy(a, pos, newarr, pos + 1, length - pos);
				a = newarr;
			}
			else
			{
				cs.system.Array.Copy(a, pos, a, pos + 1, length - pos);
				cs.system.Array.Copy(a, 0, a, 0, pos);
			}
		}
		a[pos] = x;
	}
	#else
	static function removeInt(a:cs.NativeArray<Int>, length:Int, pos:Int)
	{
		cs.system.Array.Copy(a, pos + 1, a, pos, length - pos - 1);
		a[length - 1] = 0;
	}
	static function removeFloat(a:cs.NativeArray<Float>, length:Int, pos:Int)
	{
		cs.system.Array.Copy(a, pos + 1, a, pos, length - pos - 1);
		a[length - 1] = 0;
	}
	static function removeDynamic(a:cs.NativeArray<Dynamic>, length:Int, pos:Int)
	{
		cs.system.Array.Copy(a, pos + 1, a, pos, length - pos - 1);
		a[length - 1] = null;
	}

	@:extern
	static inline function __insert<T>(a:cs.NativeArray<T>, length:Int, pos:Int, x:T):cs.NativeArray<T>
	{
		var capacity = a.Length;
		if (pos == length)
		{
			if (capacity == length)
			{
				var newarr = new NativeArray((length << 1) + 1);
				a.CopyTo(newarr, 0);
				a = newarr;
			}
		}
		else if (pos == 0)
		{
			if (capacity == length)
			{
				var newarr = new NativeArray((length << 1) + 1);
				cs.system.Array.Copy(a, 0, newarr, 1, length);
				a = newarr;
			}
			else
			{
				cs.system.Array.Copy(a, 0, a, 1, length);
			}
		}
		else
		{
			if (capacity == length)
			{
				var newarr = new NativeArray((length << 1) + 1);
				cs.system.Array.Copy(a, 0, newarr, 0, pos);
				cs.system.Array.Copy(a, pos, newarr, pos + 1, length - pos);
				a = newarr;
			}
			else
			{
				cs.system.Array.Copy(a, pos, a, pos + 1, length - pos);
				cs.system.Array.Copy(a, 0, a, 0, pos);
			}
		}
		a[pos] = x;
		return a;
	}

	static function insertInt(a:cs.NativeArray<Int>, length:Int, pos:Int, x:Int):cs.NativeArray<Int> return __insert(a, length, pos, x);
	static function insertFloat(a:cs.NativeArray<Float>, length:Int, pos:Int, x:Float):cs.NativeArray<Float> return __insert(a, length, pos, x);
	static function insertDynamic(a:cs.NativeArray<Dynamic>, length:Int, pos:Int, x:Dynamic):cs.NativeArray<Dynamic> return __insert(a, length, pos, x);
	#end
}