package passgo

/*
#cgo LDFLAGS: -landroid -llog

#include <stdlib.h>
#include "jni_android.h"
*/
import "C"

import (
	"errors"
	"fmt"
	"log"
	"runtime"
	"unsafe"
	"sync"
)

var theJVM *C.JavaVM
type JNIEnv = C.JNIEnv

func SetJVM(jvm uintptr) {
	log.Print("set theJVM")
	theJVM = (*C.JavaVM)(unsafe.Pointer(jvm))
}

func JniCallVoidMethod(env *C.JNIEnv, obj C.jobject, methodID C.jmethodID) {
	C.CallVoidMethod(env, obj, methodID)
}

type PGP C.jobject

var (
	fragChans map[int]chan string
	chmux sync.Mutex
	chint int
)

func (p PGP) GetId() (string, error) {
	ch := make(chan string)
	chmux.Lock()
	if fragChans == nil {
		fragChans = make(map[int]chan string)
	}
	fragChans[chint] = ch
	curint := chint
	chint++
	chmux.Unlock()

	RunInJVM(func(env *JNIEnv) {
		C.GetId(env, (C.jobject)(p), C.int(curint))
	})
	log.Printf("GetId(): waiting for response")
	switch x := <-ch; {
	case x == "":
		log.Printf("GetId(): failed")
		return "", fmt.Errorf("GetId failed")
	default:
		log.Printf("GetId(): got %s", x)
		return x, nil
	}
}

func (p PGP) Decrypt(data string) (string, error) {
	ch := make(chan string)
	chmux.Lock()
	if fragChans == nil {
		fragChans = make(map[int]chan string)
	}
	fragChans[chint] = ch
	curint := chint
	chint++
	chmux.Unlock()

	cdata := C.CString(data)
	defer C.free(unsafe.Pointer(cdata))
	RunInJVM(func(env *JNIEnv) {
		C.Decrypt(env, (C.jobject)(p), (*C.char)(unsafe.Pointer(cdata)), (C.int)(len(data)), C.int(curint))
	})
	switch x := <-ch; {
	case x == "":
		return "", fmt.Errorf("Decryption failed")
	default:
		return x, nil
	}
}

func (p PGP) Encrypt(id, data string) (string, error) {
	ch := make(chan string)
	chmux.Lock()
	if fragChans == nil {
		fragChans = make(map[int]chan string)
	}
	fragChans[chint] = ch
	curint := chint
	chint++
	chmux.Unlock()

	cid := C.CString(id)
	defer C.free(unsafe.Pointer(cid))
	cdata := C.CString(data)
	defer C.free(unsafe.Pointer(cdata))
	RunInJVM(func(env *JNIEnv) {
		C.Encrypt(env, (C.jobject)(p), (*C.char)(unsafe.Pointer(cid)), (C.int)(len(id)), (*C.char)(unsafe.Pointer(cdata)), (C.int)(len(data)), C.int(curint))
	})
	switch x := <-ch; {
	case x == "":
		return "", fmt.Errorf("Encryption failed")
	default:
		return x, nil
	}
}

func (p PGP) Clip(data string) {
	cdata := C.CString(data)
	defer C.free(unsafe.Pointer(cdata))
	RunInJVM(func(env *JNIEnv) {
		C.Clip(env, (C.jobject)(p), (*C.char)(unsafe.Pointer(cdata)), (C.int)(len(data)))
	})
}

func RunInJVM(f func(env *C.JNIEnv)) {
	runtime.LockOSThread()
	defer runtime.UnlockOSThread()
	var env *C.JNIEnv
	var detach bool
	if res := C.GetEnv(theJVM, &env, C.JNI_VERSION_1_6); res != C.JNI_OK {
		if res != C.JNI_EDETACHED {
			panic(fmt.Errorf("JNI GetEnv failed with error %d", res))
		}
		if C.AttachCurrentThread(theJVM, &env, nil) != C.JNI_OK {
			panic(errors.New("runInJVM: AttachCurrentThread failed"))
		}
		detach = true
	}

	if detach {
		defer func() {
			C.DetachCurrentThread(theJVM)
		}()
	}
	f(env)
}

//export goStringResult
func goStringResult(env *C.JNIEnv, class C.jclass, request C.jint, str *C.char) {
	fragChans[int(request)] <- C.GoString(str)
	C.free(unsafe.Pointer(str))
	chmux.Lock()
	delete(fragChans, int(request))
	chmux.Unlock()
}