/*
 * Copyright (C) 2019 Intel Corporation.  All rights reserved.
 * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 */

#include "bh_thread.h"
#include "bh_assert.h"
#include "bh_log.h"
#include "bh_memory.h"
#include <stdio.h>
#include <stdlib.h>


struct bh_thread_data;
typedef struct bh_thread_wait_node {
  aos_sem_t sem;
  bh_thread_wait_list next;
} bh_thread_wait_node;

typedef struct bh_thread_data {
  /* Thread body */
  aos_task_t thread;
  /* Thread start routine */
  thread_start_routine_t start_routine;
  /* Thread start routine argument */
  void *arg;
  /* Thread local root */
  void *tlr;
  /* Wait node of current thread */
  bh_thread_wait_node wait_node;
  /* Lock for waiting list */
  aos_mutex_t wait_list_lock;
  /* Waiting list of other threads who are joining this thread */
  bh_thread_wait_list thread_wait_list;
} bh_thread_data;

static bool is_thread_sys_inited = false;

/* Thread data of supervisor thread */
static bh_thread_data supervisor_thread_data;

/* Thread data key */
static aos_task_key_t thread_data_key;

/* Thread name index */
static int thread_name_index;

int
_vm_thread_sys_init()
{
  if (is_thread_sys_inited)
    return BHT_OK;

  if (aos_task_key_create(&thread_data_key) != 0)
    return BHT_ERROR;

  /* Initialize supervisor thread data */
  memset(&supervisor_thread_data, 0, sizeof(supervisor_thread_data));

  if (aos_sem_new(&supervisor_thread_data.wait_node.sem, 1) != 0) {
    aos_task_key_delete(thread_data_key);
    return BHT_ERROR;
  }

  if (aos_task_setspecific(thread_data_key, &supervisor_thread_data)) {
    aos_sem_free(&supervisor_thread_data.wait_node.sem);
    aos_task_key_delete(thread_data_key);
    return BHT_ERROR;
  }

  is_thread_sys_inited = true;
  return BHT_OK;
}

void
vm_thread_sys_destroy()
{
  if (is_thread_sys_inited) {
    aos_task_key_delete(thread_data_key);
    aos_sem_free(&supervisor_thread_data.wait_node.sem);
    is_thread_sys_inited = false;
  }
}

static bh_thread_data *
thread_data_current()
{
  return aos_task_getspecific(thread_data_key);
}

static void
vm_thread_cleanup(void)
{
  bh_thread_data *thread_data = thread_data_current();
  bh_thread_wait_list thread_wait_list;
  aos_mutex_t *wait_list_lock;
  aos_sem_t *wait_node_sem;

  bh_assert(thread_data != NULL);
  wait_list_lock = &thread_data->wait_list_lock;
  thread_wait_list = thread_data->thread_wait_list;
  wait_node_sem = &thread_data->wait_node.sem;

  /* Free thread data firstly */
  bh_free(thread_data);

  aos_mutex_lock(wait_list_lock, AOS_WAIT_FOREVER);
  if (thread_wait_list) {
    /* Signal each joining thread */
    bh_thread_wait_list head = thread_wait_list;
    while (head) {
      bh_thread_wait_list next = head->next;
      aos_sem_signal(&head->sem);
      head = next;
    }
  }
  aos_mutex_unlock(wait_list_lock);

  /* Free sem and lock */
  aos_sem_free(wait_node_sem);
  aos_mutex_free(wait_list_lock);
}

static void
vm_thread_wrapper(void *arg)
{
  bh_thread_data *thread_data = arg;

  /* Set thread custom data */
  if (!aos_task_setspecific(thread_data_key, thread_data))
    thread_data->start_routine(thread_data->arg);

  vm_thread_cleanup();
}

int
_vm_thread_create(korp_tid *p_tid, thread_start_routine_t start,
                  void *arg, unsigned int stack_size)
{
  return _vm_thread_create_with_prio(p_tid, start, arg, stack_size,
                                     BH_THREAD_DEFAULT_PRIORITY);
}

int
_vm_thread_create_with_prio(korp_tid *p_tid, thread_start_routine_t start,
                            void *arg, unsigned int stack_size, int prio)
{
  bh_thread_data *thread_data;
  char thread_name[32];

  if (!p_tid || !stack_size)
    return BHT_ERROR;

  /* Create and initialize thread data */
  if (!(thread_data = bh_malloc(sizeof(bh_thread_data))))
    return BHT_ERROR;

  memset(thread_data, 0, sizeof(bh_thread_data));

  thread_data->start_routine = start;
  thread_data->arg = arg;

  if (aos_sem_new(&thread_data->wait_node.sem, 1) != 0)
    goto fail1;

  if (aos_mutex_new(&thread_data->wait_list_lock))
    goto fail2;

  snprintf(thread_name, sizeof(thread_name), "%s%d",
           "wasm-thread-", ++thread_name_index);

  /* Create the thread */
  if (aos_task_new_ext((aos_task_t*)thread_data, thread_name,
                        vm_thread_wrapper, thread_data,
                        stack_size, prio))
    goto fail3;

  aos_msleep(10);
  *p_tid = (korp_tid)thread_data;
  return BHT_OK;

fail3:
  aos_mutex_free(&thread_data->wait_list_lock);
fail2:
  aos_sem_free(&thread_data->wait_node.sem);
fail1:
  bh_free(thread_data);
  return BHT_ERROR;
}

korp_tid
_vm_self_thread()
{
  return (korp_tid)aos_task_getspecific(thread_data_key);
}

void
vm_thread_exit(void * code)
{
  vm_thread_cleanup();
  aos_task_exit((int)(intptr_t)code);
}

int
_vm_thread_cancel (korp_tid thread)
{
  /* TODO */
  return 0;
}

int
_vm_thread_join (korp_tid thread, void **value_ptr, int mills)
{
  (void)value_ptr;
  bh_thread_data *thread_data, *curr_thread_data;

  /* Get thread data of current thread */
  curr_thread_data = thread_data_current();
  curr_thread_data->wait_node.next = NULL;

  /* Get thread data */
  thread_data = (bh_thread_data*)thread;

  aos_mutex_lock(&thread_data->wait_list_lock, AOS_WAIT_FOREVER);
  if (!thread_data->thread_wait_list)
    thread_data->thread_wait_list = &curr_thread_data->wait_node;
  else {
    /* Add to end of waiting list */
    bh_thread_wait_node *p = thread_data->thread_wait_list;
    while (p->next)
      p = p->next;
    p->next = &curr_thread_data->wait_node;
  }
  aos_mutex_unlock(&thread_data->wait_list_lock);

  /* Wait the sem */
  aos_sem_wait(&curr_thread_data->wait_node.sem, mills);

  return BHT_OK;
}

int
_vm_thread_detach (korp_tid thread)
{
  (void)thread;
  return BHT_OK;
}

void *
_vm_tls_get(unsigned idx)
{
  (void)idx;
  bh_thread_data *thread_data;

  bh_assert (idx == 0);
  thread_data = thread_data_current();

  return thread_data ? thread_data->tlr : NULL;
}

int
_vm_tls_put(unsigned idx, void * tls)
{
  bh_thread_data *thread_data;

  (void)idx;
  bh_assert (idx == 0);
  thread_data = thread_data_current();
  bh_assert (thread_data != NULL);

  thread_data->tlr = tls;
  return BHT_OK;
}

int
_vm_mutex_init(korp_mutex *mutex)
{
  return aos_mutex_new(mutex) == 0 ? BHT_OK : BHT_ERROR;
}

int
_vm_recursive_mutex_init(korp_mutex *mutex)
{
  return aos_mutex_new(mutex) == 0 ? BHT_OK : BHT_ERROR;
}

int
_vm_mutex_destroy(korp_mutex *mutex)
{
  aos_mutex_free(mutex);
  return BHT_OK;
}

void
vm_mutex_lock(korp_mutex *mutex)
{
  aos_mutex_lock(mutex, AOS_WAIT_FOREVER);
}

int
vm_mutex_trylock(korp_mutex *mutex)
{
  return aos_mutex_lock(mutex, AOS_NO_WAIT);
}

void vm_mutex_unlock(korp_mutex *mutex)
{
  aos_mutex_unlock(mutex);
}

int _vm_sem_init(korp_sem* sem, unsigned int c)
{
  return aos_sem_new(sem, c) == 0 ? BHT_OK : BHT_ERROR;
}

int _vm_sem_destroy(korp_sem *sem)
{
  aos_sem_free(sem);
  return BHT_OK;
}

int _vm_sem_wait(korp_sem *sem)
{
  return aos_sem_wait(sem, AOS_WAIT_FOREVER);
}

int _vm_sem_reltimedwait(korp_sem *sem, int mills)
{
  return aos_sem_wait(sem, mills);
}

int _vm_sem_post(korp_sem *sem)
{
  aos_sem_signal(sem);
  return BHT_OK;
}

int
_vm_cond_init(korp_cond *cond)
{
  if (aos_mutex_new(&cond->wait_list_lock) != 0)
    return BHT_ERROR;

  cond->thread_wait_list = NULL;
  return BHT_OK;
}

int
_vm_cond_destroy(korp_cond *cond)
{
  aos_mutex_free(&cond->wait_list_lock);
  return BHT_OK;
}

static int
vm_cond_wait_internal(korp_cond *cond, korp_mutex *mutex,
                      bool timed, int mills)
{
  bh_thread_wait_node *node = &thread_data_current()->wait_node;

  node->next = NULL;

  aos_mutex_lock(&cond->wait_list_lock, AOS_WAIT_FOREVER);
  if (!cond->thread_wait_list)
    cond->thread_wait_list = node;
  else {
    /* Add to end of wait list */
    bh_thread_wait_node *p = cond->thread_wait_list;
    while (p->next)
      p = p->next;
    p->next = node;
  }
  aos_mutex_unlock(&cond->wait_list_lock);

  /* Unlock mutex, wait sem and lock mutex again */
  aos_mutex_unlock(mutex);
  aos_sem_wait(&node->sem, timed ? mills : AOS_WAIT_FOREVER);
  aos_mutex_lock(mutex, AOS_WAIT_FOREVER);

  /* Remove wait node from wait list */
  aos_mutex_lock(&cond->wait_list_lock, AOS_WAIT_FOREVER);
  if (cond->thread_wait_list == node)
    cond->thread_wait_list = node->next;
  else {
    /* Remove from the wait list */
    bh_thread_wait_node *p = cond->thread_wait_list;
    while (p->next != node)
      p = p->next;
    p->next = node->next;
  }
  aos_mutex_unlock(&cond->wait_list_lock);

  return BHT_OK;
}

int
_vm_cond_wait(korp_cond *cond, korp_mutex *mutex)
{
  return vm_cond_wait_internal(cond, mutex, false, 0);
}

int
_vm_cond_reltimedwait(korp_cond *cond, korp_mutex *mutex, int mills)
{
  return vm_cond_wait_internal(cond, mutex, true, mills);
}

int
_vm_cond_signal(korp_cond *cond)
{
  /* Signal the head wait node of wait list */
  aos_mutex_lock(&cond->wait_list_lock, AOS_WAIT_FOREVER);
  if (cond->thread_wait_list)
    aos_sem_signal(&cond->thread_wait_list->sem);
  aos_mutex_unlock(&cond->wait_list_lock);

  return BHT_OK;
}

int
_vm_cond_broadcast (korp_cond *cond)
{
  /* Signal each wait node of wait list */
  aos_mutex_lock(&cond->wait_list_lock, AOS_WAIT_FOREVER);
  if (cond->thread_wait_list) {
    bh_thread_wait_node *p = cond->thread_wait_list;
    while (p) {
      aos_sem_signal(&p->sem);
      p = p->next;
    }
  }
  aos_mutex_unlock(&cond->wait_list_lock);

  return BHT_OK;
}