/*
 Serene --- Yet an other Lisp

Copyright (c) 2020  Sameer Rahmani <lxsameer@gnu.org>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 2 of the License.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

package dl

/*
#cgo linux LDFLAGS: -ldl
#cgo pkg-config: libffi
#include <dlfcn.h>
#include <limits.h>
#include <stdlib.h>
#include <stdint.h>

#include <stdio.h>

static uintptr_t openShareLib(const char* path, char** err) {
	void* h = dlopen(path, RTLD_NOW|RTLD_GLOBAL);
	if (h == NULL) {
		*err = (char*)dlerror();
	}
	return (uintptr_t)h;
}

static void* shareLibLookup(uintptr_t h, const char* name, char** err) {
	void* r = dlsym((void*)h, name);
	if (r == NULL) {
		*err = (char*)dlerror();
	}
	return r;
}
*/
import "C"
import (
	"fmt"
	"unsafe"
)

type SharedLib struct{}

func Open(libPath string) (*SharedLib, error) {
	cPath := make([]byte, C.PATH_MAX+1)
	cRelName := make([]byte, len(libPath)+1)
	copy(cRelName, libPath)

	// If the given libPath exists, fill the cPath with the absolute path
	// to the file (it follows symlinks).
	if C.realpath(
		(*C.char)(unsafe.Pointer(&cRelName[0])),
		(*C.char)(unsafe.Pointer(&cPath[0]))) == nil {
		return nil, fmt.Errorf("can't find the shared library '%s'", libPath)
	}

	//filepath := C.GoString((*C.char)(unsafe.Pointer(&cPath[0])))

	var cErr *C.char
	h := C.openShareLib((*C.char)(unsafe.Pointer(&cPath[0])), &cErr)

	if h == 0 {
		// lock.Unlock()
		return nil, fmt.Errorf("failed to open shared library: '%s' due to: '%s'", libPath, C.GoString(cErr))
	}

	// if plugins == nil {
	// 	plugins = make(map[string]*Plugin)
	// }
	initTask := C.shareLibLookup(h, C.CString("bar"), &cErr)

	fmt.Printf(">> %p \n", initTask)

	return &SharedLib{}, nil
}