package lua;
/**
  A set of utility methods for working with the Lua table extern.
 **/
class PairTools {
	public static function ipairsEach<T>(table:Table<Dynamic,T>, func : Int->T->Void) : Void {
		untyped __lua__("for i,v in _G.ipairs(table) do func(i,v) end");
	}
	public static function pairsEach<A,B>(table:Table<A,B>, func : A->B->Void) : Void {
		untyped __lua__("for k,v in _G.pairs(table) do func(k,v) end");
	}
	public static function ipairsMap<A,B>(table:Table<Dynamic,A>, func : Int->A->B) : Table<Int,B>  {
		var ret : Table<Int,B> = Table.create();
		untyped __lua__( "for i,v in _G.ipairs(table) do ret[i] = func(i,v) end;");
		return ret;
	}
	public static function pairsMap<A,B,C>(table:Table<A,B>, func : A->B->C->C) : Table<A,C> {
		var ret : Table<A,C> = Table.create();
		untyped __lua__( "for k,v in _G.pairs(table) do ret[k] = func(k,v) end;");
		return ret;
	}
	public static function ipairsFold<A,B>(table:Table<Int,A>, func : Int->A->B->B, seed: B) : B  {
		untyped __lua__("for i,v in _G.ipairs(table) do seed = func(i,v,seed) end");
		return untyped __lua__("seed");
	}
	public static function pairsFold<A,B,C>(table:Table<A,B>, func : A->B->C->C, seed: C) : C {
		untyped __lua__("for k,v in _G.pairs(table) do seed = func(k,v,seed) end");
		return untyped __lua__("seed");
	}

	public static function ipairsConcat<T>(table1:Table<Int,T>, table2:Table<Int,T>){
		var ret:Table<Int,T> = Table.create();
		ipairsFold(table1, function(a,b,c:Table<Int,T>){ c[a] = b; return c;}, ret);
		var size = lua.TableTools.maxn(ret);
		ipairsFold(table2, function(a,b,c:Table<Int,T>){ c[a + size] = b; return c;}, ret);
		return ret;
	}

	public static function pairsMerge<A,B>(table1:Table<A,B>, table2:Table<A,B>){
		var ret = copy(table1);
		pairsEach(table2, function(a,b:B) ret[cast a] = b);
		return ret;
	}

	public static function ipairsExist<T>(table:Table<Int,T>, func: Int->T->Bool) {
		untyped __lua__("for k,v in _G.ipairs(table) do if func(k,v) then return true end end");
	}

	public static function pairsExist<A,B>(table:Table<A,B>, func: A->B->Bool) {
		untyped __lua__("for k,v in _G.pairs(table) do if func(k,v) then return true end end");
	}

	public static function copy<A,B>(table1:Table<A,B>) : Table<A,B> {
		var ret : Table<A,B> = Table.create();
		untyped __lua__("for k,v in _G.pairs(table1) do ret[k] = v end");
		return ret;
	}

	public static function pairsIterator<A,B>(table:Table<A,B>) : Iterator<{index:A, value:B}> {
		var p = Lua.pairs(table);
		var next = p.next;
		var i = p.index;
		return {
			next : function(){
				var res = next(table,i);
				i = res.index;
				return {index : res.index, value : res.value};
			},
			hasNext : function(){
				return Lua.next(table, i).value != null;
			}
		}
	}

	public static function ipairsIterator<A,B>(table:Table<A,B>) : Iterator<{index:Int, value:B}> {
		var p = Lua.ipairs(table);
		var next = p.next;
		var i = p.index;
		return {
			next : function(){
				var res = next(table,i);
				i = res.index;
				return {index : res.index, value : res.value};
			},
			hasNext : function(){
				return next(table, i).value != null;
			}
		}
	}
}