/*
 * Copyright (C)2005-2019 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.
 */

import python.internal.AnonObject;
import python.internal.EnumImpl;
import python.internal.Internal;
import python.internal.UBuiltins;
import python.Syntax;

enum ValueType {
	TNull;
	TInt;
	TFloat;
	TBool;
	TObject;
	TFunction;
	TClass(c:Class<Dynamic>);
	TEnum(e:Enum<Dynamic>);
	TUnknown;
}

@:access(python.Boot)
@:coreApi class Type {
	public static function getClass<T>(o:T):Null<Class<T>> {
		if (o == null)
			return null;

		if (python.Boot.isClass(o))
			return null;

		if (python.Boot.isAnonObject(o))
			return null;

		if (Internal.hasClass(o)) {
			return Internal.fieldClass(o);
		}
		if (UBuiltins.hasattr(o, "__class__")) {
			return Syntax.field(o, "__class__");
		} else {
			return null;
		}
	}

	public static function getEnum(o:EnumValue):Enum<Dynamic> {
		if (o == null)
			return null;
		return Syntax.field(o, "__class__");
	}

	public static function getSuperClass(c:Class<Dynamic>):Class<Dynamic> {
		return python.Boot.getSuperClass(c);
	}

	public static function getClassName(c:Class<Dynamic>):String {
		if (Internal.hasClassName(c)) {
			return Internal.fieldClassName(c);
		} else {
			// it's not a Haxe class
			if (c == Array)
				return "Array";
			if (c == Math)
				return "Math";
			if (c == String)
				return "String";

			try {
				return Syntax.field(c, "__name__");
			} catch (e:Dynamic) {
				return null;
			}
		}
	}

	public static function getEnumName(e:Enum<Dynamic>):String {
		return Internal.fieldClassName(e);
	}

	public static function resolveClass(name:String):Class<Dynamic> {
		if (name == "Array")
			return Array;
		if (name == "Math")
			return Math;
		if (name == "String")
			return String;

		var cl:Class<Dynamic> = Internal.classRegistry().get(name, null);
		// ensure that this is a class
		if (cl == null || !python.Boot.isClass(cl))
			return null;
		return cl;
	}

	public static function resolveEnum(name:String):Enum<Dynamic> {
		if (name == "Bool")
			return cast Bool;
		var o = resolveClass(name);
		return if (Internal.hasConstructs(o)) cast o else null;
	}

	public static inline function createInstance<T>(cl:Class<T>, args:Array<Dynamic>):T {
		return Syntax.construct(cl, Syntax.varArgs(args));
	}

	public static function createEmptyInstance<T>(cl:Class<T>):T {
		var i = Syntax.callField(cl, "__new__", cl);

		function callInit(cl) {
			var sc = getSuperClass(cl);
			if (sc != null) {
				callInit(sc);
			}
			if (Internal.hasEmptyInit(cl)) {
				Internal.callEmptyInit(cl, i);
			}
		}
		callInit(cl);

		return i;
	}

	public static function createEnum<T>(e:Enum<T>, constr:String, ?params:Array<Dynamic>):T {
		var f:Dynamic = Reflect.field(e, constr);
		if (f == null)
			throw "No such constructor " + constr;
		if (Reflect.isFunction(f)) {
			if (params == null)
				throw "Constructor " + constr + " need parameters";

			return Reflect.callMethod(e, f, params);
		}
		if (params != null && params.length != 0)
			throw "Constructor " + constr + " does not need parameters";
		return f;
	}

	public static function createEnumIndex<T>(e:Enum<T>, index:Int, ?params:Array<Dynamic>):T {
		var c:String = Internal.fieldConstructs(e)[index];
		if (c == null)
			throw index + " is not a valid enum constructor index";
		return createEnum(e, c, params);
	}

	public static inline function getInstanceFields(c:Class<Dynamic>):Array<String> {
		return python.Boot.getInstanceFields(c);
	}

	public static inline function getClassFields(c:Class<Dynamic>):Array<String> {
		return python.Boot.getClassFields(c);
	}

	public static function getEnumConstructs(e:Enum<Dynamic>):Array<String> {
		if (UBuiltins.hasattr(e, Internal.constructsVal())) {
			var x:Array<String> = Internal.fieldConstructs(e);
			return x.copy();
		} else {
			return [];
		}
	}

	public static function typeof(v:Dynamic):ValueType {
		if (v == null) {
			return TNull;
		} else if (UBuiltins.isinstance(v, UBuiltins.bool)) {
			return TBool;
		} else if (UBuiltins.isinstance(v, UBuiltins.int)) {
			return TInt;
		} else if (UBuiltins.isinstance(v, UBuiltins.float)) {
			return TFloat;
		} else if (UBuiltins.isinstance(v, String)) {
			return TClass(String);
		} else if (UBuiltins.isinstance(v, Array)) {
			return TClass(Array);
		} else if (UBuiltins.isinstance(v, AnonObject) || python.lib.Inspect.isclass(v)) {
			return TObject;
		} else if (UBuiltins.isinstance(v, Enum)) {
			return TEnum(Syntax.field(v, "__class__"));
		} else if (UBuiltins.isinstance(v, UBuiltins.type) || Internal.hasClass(v)) {
			return TClass(Syntax.field(v, "__class__"));
		} else if (UBuiltins.callable(v)) {
			return TFunction;
		} else {
			return TUnknown;
		}
	}

	static inline function asEnumImpl(x:Dynamic):EnumImpl {
		return (cast x : EnumImpl);
	}

	public static function enumEq<T>(a:T, b:T):Bool {
		if (a == b)
			return true;
		try {
			if (b == null && a != b)
				return false;
			if (asEnumImpl(a).tag != asEnumImpl(b).tag)
				return false;
			var p1 = asEnumImpl(a).params;
			var p2 = asEnumImpl(b).params;
			if (p1.length != p2.length)
				return false;

			for (i in 0...p1.length)
				if (!enumEq(p1[i], p2[i]))
					return false;

			if (Internal.fieldClass(a) != Internal.fieldClass(b))
				return false;
		} catch (e:Dynamic) {
			return false;
		}
		return true;
	}

	public static inline function enumConstructor(e:EnumValue):String {
		return asEnumImpl(e).tag;
	}

	public static inline function enumParameters(e:EnumValue):Array<Dynamic> {
		return asEnumImpl(e).params.toArray();
	}

	public static inline function enumIndex(e:EnumValue):Int {
		return asEnumImpl(e).index;
	}

	public static function allEnums<T>(e:Enum<T>):Array<T> {
		var ctors = getEnumConstructs(e);
		var ret = [];
		for (ctor in ctors) {
			var v = Reflect.field(e, ctor);
			if (Std.isOfType(v, e))
				ret.push(v);
		}

		return ret;
	}
}
