// Copyright 2015 The Vanadium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// +build java android

package util

import (
	"fmt"
	"unsafe"
)

// #include <stdlib.h>
// #include "jni_wrapper.h"
//
// static jvalue* allocJValueArray(int elements) {
//   return malloc(sizeof(jvalue) * elements);
// }
//
// static void setJValueArrayElement(jvalue* arr, int index, jvalue val) {
//   arr[index] = val;
// }
//
import "C"

// jArgArray converts a slice of Go args to an array of Java args.  It uses the provided slice of
// Signs to validate that the arguments are of compatible types.
func jArgArray(env Env, args []interface{}, argSigns []Sign) (jArr *C.jvalue, freeFunc func(), err error) {
	if len(argSigns) != len(args) {
		return nil, nil, fmt.Errorf("mismatch in number of arguments, want %d, got %d", len(argSigns), len(args))
	}
	jArr = C.allocJValueArray(C.int(len(args)))
	freeFunc = func() {
		C.free(unsafe.Pointer(jArr))
	}
	for i, arg := range args {
		sign := argSigns[i]
		jVal, ok := jValue(env, arg, sign)
		if !ok {
			freeFunc()
			return nil, nil, fmt.Errorf("couldn't get Java value for argument #%d [%#v] of expected type %v", i, arg, sign)
		}
		C.setJValueArrayElement(jArr, C.int(i), jVal)
	}
	return
}

// NewObject invokes a java constructor with the given arguments, returning the
// newly created object.
func NewObject(env Env, class Class, argSigns []Sign, args ...interface{}) (Object, error) {
	jcid, err := jMethodID(env, class, "<init>", FuncSign(argSigns, VoidSign))
	if err != nil {
		return NullObject, err
	}
	jArr, freeFunc, err := jArgArray(env, args, argSigns)
	if err != nil {
		return NullObject, err
	}
	defer freeFunc()
	obj := C.NewObjectA(env.value(), class.value(), jcid, jArr)
	err = JExceptionMsg(env)
	return WrapObject(uintptr(unsafe.Pointer(obj))), err
}

// jMethodID returns the Java method ID for the given instance (non-static)
// method, or an error if the method couldn't be found.
func jMethodID(env Env, class Class, name string, signature Sign) (C.jmethodID, error) {
	cName := C.CString(name)
	defer C.free(unsafe.Pointer(cName))
	cSignature := C.CString(string(signature))
	defer C.free(unsafe.Pointer(cSignature))
	mid := C.GetMethodID(env.value(), class.value(), cName, cSignature)
	if err := JExceptionMsg(env); err != nil || mid == C.jmethodID(nil) {
		return nil, fmt.Errorf("couldn't find method %q with signature %v.", name, signature)
	}
	return mid, nil
}

// jStaticMethodID returns the Java method ID for the given static method, or an
// error if the method couldn't be found.
func jStaticMethodID(env Env, class Class, name string, signature Sign) (C.jmethodID, error) {
	cName := C.CString(name)
	defer C.free(unsafe.Pointer(cName))
	cSignature := C.CString(string(signature))
	defer C.free(unsafe.Pointer(cSignature))
	mid := C.GetStaticMethodID(env.value(), class.value(), cName, cSignature)
	if err := JExceptionMsg(env); err != nil || mid == C.jmethodID(nil) {
		return nil, fmt.Errorf("couldn't find method %s with a given signature: %s", name, signature)
	}
	return mid, nil
}

// setupMethodCall performs the shared preparation operations between various
// Java method invocation functions.
func setupMethodCall(env Env, obj Object, name string, argSigns []Sign, retSign Sign, args ...interface{}) (mid C.jmethodID, jArgArr *C.jvalue, freeFunc func(), err error) {
	class := GetClass(env, obj)
	mid, err = jMethodID(env, class, name, FuncSign(argSigns, retSign))
	if err != nil {
		return
	}
	jArgArr, freeFunc, err = jArgArray(env, args, argSigns)
	if err != nil {
		err = fmt.Errorf("error creating arguments for method %s: %v", name, err)
	}
	return

}

// setupStaticMethodCall performs the shared preparation operations between
// various Java static method invocation functions.
func setupStaticMethodCall(env Env, class Class, name string, argSigns []Sign, retSign Sign, args ...interface{}) (mid C.jmethodID, jArgArr *C.jvalue, freeFunc func(), err error) {
	mid, err = jStaticMethodID(env, class, name, FuncSign(argSigns, retSign))
	if err != nil {
		return
	}
	jArgArr, freeFunc, err = jArgArray(env, args, argSigns)
	if err != nil {
		err = fmt.Errorf("error creating arguments for method %s: %v", name, err)
	}
	return
}

// CallObjectMethod calls a Java method that returns a java object.
func CallObjectMethod(env Env, obj Object, name string, argSigns []Sign, retSign Sign, args ...interface{}) (Object, error) {
	switch retSign {
	case ByteSign, CharSign, ShortSign, LongSign, FloatSign, DoubleSign, BoolSign, IntSign, VoidSign:
		panic(fmt.Sprintf("Illegal call to CallObjectMethod on method with return sign %s", retSign))
	}
	jmid, jArgArr, freeFunc, err := setupMethodCall(env, obj, name, argSigns, retSign, args...)
	if err != nil {
		return NullObject, err
	}
	defer freeFunc()
	ret := C.CallObjectMethodA(env.value(), obj.value(), jmid, jArgArr)
	return WrapObject(uintptr(unsafe.Pointer(ret))), JExceptionMsg(env)
}

// CallStringMethod calls a Java method that returns a string.
func CallStringMethod(env Env, obj Object, name string, argSigns []Sign, args ...interface{}) (string, error) {
	strObj, err := CallObjectMethod(env, obj, name, argSigns, StringSign, args...)
	return GoString(env, strObj), err
}

// CallByteArrayMethod calls a Java method that returns a byte array.
func CallByteArrayMethod(env Env, obj Object, name string, argSigns []Sign, args ...interface{}) ([]byte, error) {
	arrObj, err := CallObjectMethod(env, obj, name, argSigns, ArraySign(ByteSign), args...)
	if err != nil {
		return nil, err
	}
	return GoByteArray(env, arrObj), nil
}

// CallObjectArrayMethod calls a Java method that returns an object array.
func CallObjectArrayMethod(env Env, obj Object, name string, argSigns []Sign, retElemSign Sign, args ...interface{}) ([]Object, error) {
	arrObj, err := CallObjectMethod(env, obj, name, argSigns, ArraySign(retElemSign), args...)
	if err != nil {
		return nil, err
	}
	return GoObjectArray(env, arrObj)
}

// CallStringArrayMethod calls a Java method that returns an string array.
func CallStringArrayMethod(env Env, obj Object, name string, argSigns []Sign, args ...interface{}) ([]string, error) {
	arrObj, err := CallObjectMethod(env, obj, name, argSigns, ArraySign(StringSign), args...)
	if err != nil {
		return nil, err
	}
	return GoStringArray(env, arrObj)
}

// CallMapMethod calls a Java method that returns a map.
func CallMapMethod(env Env, obj Object, name string, argSigns []Sign, args ...interface{}) (map[Object]Object, error) {
	mapObj, err := CallObjectMethod(env, obj, name, argSigns, MapSign, args...)
	if err != nil {
		return nil, err
	}
	return GoObjectMap(env, mapObj)
}

// CallMultimapMethod calls a Java method that returns a multimap.
func CallMultimapMethod(env Env, obj Object, name string, argSigns []Sign, args ...interface{}) (map[Object][]Object, error) {
	multiMapObj, err := CallObjectMethod(env, obj, name, argSigns, MultimapSign, args...)
	if err != nil {
		return nil, err
	}
	return GoObjectMultimap(env, multiMapObj)
}

// CallBooleanMethod calls a Java method that returns a boolean.
func CallBooleanMethod(env Env, obj Object, name string, argSigns []Sign, args ...interface{}) (bool, error) {
	jmid, jArgArr, freeFunc, err := setupMethodCall(env, obj, name, argSigns, BoolSign, args...)
	if err != nil {
		return false, err
	}
	defer freeFunc()
	ret := C.CallBooleanMethodA(env.value(), obj.value(), jmid, jArgArr) != C.JNI_OK
	return ret, JExceptionMsg(env)
}

// CallIntMethod calls a Java method that returns an int.
func CallIntMethod(env Env, obj Object, name string, argSigns []Sign, args ...interface{}) (int, error) {
	jmid, jArgArr, freeFunc, err := setupMethodCall(env, obj, name, argSigns, IntSign, args...)
	if err != nil {
		return 0, err
	}
	defer freeFunc()
	ret := int(C.CallIntMethodA(env.value(), obj.value(), jmid, jArgArr))
	return ret, JExceptionMsg(env)
}

// CallLongMethod calls a Java method that returns an int64.
func CallLongMethod(env Env, obj Object, name string, argSigns []Sign, args ...interface{}) (int64, error) {
	jmid, jArgArr, freeFunc, err := setupMethodCall(env, obj, name, argSigns, LongSign, args...)
	if err != nil {
		return 0, err
	}
	defer freeFunc()
	ret := int64(C.CallLongMethodA(env.value(), obj.value(), jmid, jArgArr))
	return ret, JExceptionMsg(env)
}

// CallVoidMethod calls a Java method that doesn't return anything.
func CallVoidMethod(env Env, obj Object, name string, argSigns []Sign, args ...interface{}) error {
	jmid, jArgArr, freeFunc, err := setupMethodCall(env, obj, name, argSigns, VoidSign, args...)
	if err != nil {
		return err
	}
	defer freeFunc()
	C.CallVoidMethodA(env.value(), obj.value(), jmid, jArgArr)
	return JExceptionMsg(env)
}

// CallStaticObjectMethod calls a static Java method that returns a Java object.
func CallStaticObjectMethod(env Env, class Class, name string, argSigns []Sign, retSign Sign, args ...interface{}) (Object, error) {
	switch retSign {
	case ByteSign, CharSign, ShortSign, LongSign, FloatSign, DoubleSign, BoolSign, IntSign, VoidSign:
		panic(fmt.Sprintf("Illegal call to CallStaticObjectMethod on method with return sign %s", retSign))
	}
	jmid, jArgArr, freeFunc, err := setupStaticMethodCall(env, class, name, argSigns, retSign, args...)
	if err != nil {
		return NullObject, err
	}
	defer freeFunc()
	ret := C.CallStaticObjectMethodA(env.value(), class.value(), jmid, jArgArr)
	return WrapObject(uintptr(unsafe.Pointer(ret))), JExceptionMsg(env)
}

// CallStaticStringMethod calls a static Java method that returns a string.
func CallStaticStringMethod(env Env, class Class, name string, argSigns []Sign, args ...interface{}) (string, error) {
	strObj, err := CallStaticObjectMethod(env, class, name, argSigns, StringSign, args...)
	return GoString(env, strObj), err
}

// CallStaticByteArrayMethod calls a static Java method that returns a byte array.
func CallStaticByteArrayMethod(env Env, class Class, name string, argSigns []Sign, args ...interface{}) ([]byte, error) {
	arrObj, err := CallStaticObjectMethod(env, class, name, argSigns, ArraySign(ByteSign), args...)
	if err != nil {
		return nil, err
	}
	return GoByteArray(env, arrObj), nil
}

// CallStaticLongArrayMethod calls a static Java method that returns a array of long.
func CallStaticLongArrayMethod(env Env, class Class, name string, argSigns []Sign, args ...interface{}) ([]int64, error) {
	arrObj, err := CallStaticObjectMethod(env, class, name, argSigns, ArraySign(LongSign), args...)
	if err != nil {
		return nil, err
	}
	return GoLongArray(env, arrObj), nil
}

// CallStaticIntMethod calls a static Java method that returns an int.
func CallStaticIntMethod(env Env, class Class, name string, argSigns []Sign, args ...interface{}) (int, error) {
	jmid, jArgArr, freeFunc, err := setupStaticMethodCall(env, class, name, argSigns, IntSign, args...)
	if err != nil {
		return 0, err
	}
	defer freeFunc()
	ret := int(C.CallStaticIntMethodA(env.value(), class.value(), jmid, jArgArr))
	return ret, JExceptionMsg(env)
}

// CallStaticVoidMethod calls a static Java method doesn't return anything.
func CallStaticVoidMethod(env Env, class Class, name string, argSigns []Sign, args ...interface{}) error {
	jmid, jArgArr, freeFunc, err := setupStaticMethodCall(env, class, name, argSigns, VoidSign, args...)
	if err != nil {
		return err
	}
	defer freeFunc()
	C.CallStaticVoidMethodA(env.value(), class.value(), jmid, jArgArr)
	return JExceptionMsg(env)
}

func handleError(name string, err error) {
	if err != nil {
		panic(fmt.Sprintf("error while calling jni method %q: %v", name, err))
	}
}

func isSignOneOf(sign Sign, set []Sign) bool {
	for _, s := range set {
		if sign == s {
			return true
		}
	}
	return false
}