/*
 * Copyright (c) 2024 The GoPlus Authors (goplus.org). All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package pthread

import (
	_ "unsafe"

	"github.com/goplus/llgo/c"
)

func __noop__() c.Int {
	return 0
}

// -----------------------------------------------------------------------------

type aThread struct {
	Unused [8]byte
}

// Thread represents a POSIX thread.
type Thread = *aThread

// The pthread_create() function starts a new thread in the calling
// process.  The new thread starts execution by invoking
// start_routine(); arg is passed as the sole argument of
// start_routine().
//
// The new thread terminates in one of the following ways:
//
//   - It calls pthread_exit(3), specifying an exit status value that
//     is available to another thread in the same process that calls
//     pthread_join(3).
//
//   - It returns from start_routine().  This is equivalent to
//     calling pthread_exit(3) with the value supplied in the return
//     statement.
//
//   - It is canceled (see pthread_cancel(3)).
//
//   - Any of the threads in the process calls exit(3), or the main
//     thread performs a return from main().  This causes the
//     termination of all threads in the process.
//
// On success, pthread_create() returns 0; on error, it returns an
// error number, and the contents of *thread are undefined.
//
// See https://man7.org/linux/man-pages/man3/pthread_create.3.html
//
//go:linkname Create C.llgoPthreadCreate
func Create(pthread *Thread, attr *Attr, routine func(c.Pointer) c.Pointer, arg c.Pointer) c.Int

// The pthread_join() function waits for the thread specified by
// thread to terminate.  If that thread has already terminated, then
// pthread_join() returns immediately.  The thread specified by
// thread must be joinable.
//
// If retval is not NULL, then pthread_join() copies the exit status
// of the target thread (i.e., the value that the target thread
// supplied to pthread_exit(3)) into the location pointed to by
// retval.  If the target thread was canceled, then PTHREAD_CANCELED
// is placed in the location pointed to by retval.
//
// If multiple threads simultaneously try to join with the same
// thread, the results are undefined.  If the thread calling
// pthread_join() is canceled, then the target thread will remain
// joinable (i.e., it will not be detached).
//
// See https://man7.org/linux/man-pages/man3/pthread_join.3.html
//
//go:linkname Join C.llgoPthreadJoin
func Join(thread Thread, retval *c.Pointer) c.Int

// The pthread_exit() function terminates the calling thread and
// returns a value via retval that (if the thread is joinable) is
// available to another thread in the same process that calls
// pthread_join(3).
//
// See https://man7.org/linux/man-pages/man3/pthread_exit.3.html
//
//go:linkname Exit C.pthread_exit
func Exit(retval c.Pointer)

// The pthread_cancel() function sends a cancelation request to the
// thread thread.
//
// See https://man7.org/linux/man-pages/man3/pthread_cancel.3.html
//
//go:linkname Cancel C.pthread_cancel
func Cancel(thread Thread) c.Int

// -----------------------------------------------------------------------------

// Attr represents a POSIX thread attributes.
type Attr struct {
	Detached byte
	SsSp     *c.Char
	SsSize   uintptr
}

// llgo:link (*Attr).Init C.pthread_attr_init
func (attr *Attr) Init() c.Int { return 0 }

// llgo:link (*Attr).Destroy C.pthread_attr_destroy
func (attr *Attr) Destroy() c.Int { return 0 }

// llgo:link (*Attr).GetDetached C.pthread_attr_getdetachstate
func (attr *Attr) GetDetached(detached *c.Int) c.Int { return 0 }

// llgo:link (*Attr).SetDetached C.pthread_attr_setdetachstate
func (attr *Attr) SetDetached(detached c.Int) c.Int { return 0 }

// llgo:link (*Attr).GetStackSize C.pthread_attr_getstacksize
func (attr *Attr) GetStackSize(stackSize *uintptr) c.Int { return 0 }

// llgo:link (*Attr).SetStackSize C.pthread_attr_setstacksize
func (attr *Attr) SetStackSize(stackSize uintptr) c.Int { return 0 }

// llgo:link (*Attr).GetStackAddr C.pthread_attr_getstackaddr
func (attr *Attr) GetStackAddr(stackAddr *c.Pointer) c.Int { return 0 }

// llgo:link (*Attr).SetStackAddr C.pthread_attr_setstackaddr
func (attr *Attr) SetStackAddr(stackAddr c.Pointer) c.Int { return 0 }

// -----------------------------------------------------------------------------
// Thread Local Storage

type Key c.Uint

// llgo:link (*Key).Create C.pthread_key_create
func (key *Key) Create(destructor func(c.Pointer)) c.Int { return 0 }

// llgo:link Key.Delete C.pthread_key_delete
func (key Key) Delete() c.Int { return 0 }

// llgo:link Key.Get C.pthread_getspecific
func (key Key) Get() c.Pointer { return nil }

// llgo:link Key.Set C.pthread_setspecific
func (key Key) Set(value c.Pointer) c.Int { return __noop__() }

// -----------------------------------------------------------------------------