#include <bh/internal/thread.h>
#include <string.h>
#include <stdlib.h>

static void *bh_thread_run(void *arg)
{
    bh_task_t *task;

    task = (bh_task_t *)arg;

    task->func(task->data);
    task->flags |= BH_THREAD_DONE;

    if (task->flags & BH_THREAD_CLEANUP)
        bh_task_free(task);
    
    return NULL;
}

int bh_thread_init(bh_thread_t *thread,
                   bh_task_t *task)
{
    return pthread_create(&thread->handle, NULL, bh_thread_run, task);
}

int bh_thread_join(bh_thread_t *thread)
{
    return pthread_join(thread->handle, NULL);
}

int bh_thread_detach(bh_thread_t *thread)
{
    return pthread_detach(thread->handle);
}

int bh_mutex_init(bh_mutex_t *mutex)
{
    return pthread_mutex_init(&mutex->handle, NULL);
}

void bh_mutex_destroy(bh_mutex_t *mutex)
{
    pthread_mutex_destroy(&mutex->handle);
}

int bh_mutex_lock(bh_mutex_t *mutex)
{
    return pthread_mutex_lock(&mutex->handle);
}

int bh_mutex_try_lock(bh_mutex_t *mutex)
{
    return pthread_mutex_trylock(&mutex->handle);
}

int bh_mutex_unlock(bh_mutex_t *mutex)
{
    return pthread_mutex_unlock(&mutex->handle);
}

int bh_cond_init(bh_cond_t *cond)
{
    return pthread_cond_init(&cond->handle, NULL);
}

void bh_cond_destroy(bh_cond_t *cond)
{
    pthread_cond_destroy(&cond->handle);
}

int bh_cond_wait(bh_cond_t *cond,
                 bh_mutex_t *mutex)
{
    return pthread_cond_wait(&cond->handle, &mutex->handle);
}

int bh_cond_wait_for(bh_cond_t *cond,
                     bh_mutex_t *mutex,
                     unsigned long timeout)
{
    struct timespec ts;

    ts.tv_sec = timeout / 1000;
    ts.tv_nsec = (timeout - ts.tv_sec * 1000) * 1000000;

    return pthread_cond_timedwait(&cond->handle, &mutex->handle, &ts);
}

int bh_cond_signal(bh_cond_t *cond)
{
    return pthread_cond_signal(&cond->handle);
}

int bh_cond_broadcast(bh_cond_t *cond)
{
    return pthread_cond_broadcast(&cond->handle);
}

int bh_thread_pool_init(bh_thread_pool_t *pool,
                        size_t size)
{
    size_t i;
    static bh_task_t pool_task;
    static int pool_task_init = 0;

    /* Initialize static thread pool task */
    if (!pool_task_init)
    {
        bh_task_init(&pool_task, bh_thread_pool_worker, pool, 0);
        pool_task_init = 1;
    }

    /* Zero out pool structure */
    memset(pool, 0, sizeof(*pool));

    /* Initialize mutex and condition variables */
    if (bh_mutex_init(&pool->lock))
        goto lock_fail;

    if (bh_cond_init(&pool->new_task))
        goto task_fail;
    
    if (bh_cond_init(&pool->done_task))
        goto done_fail;

    /* Allocate array of threads */
    pool->threads = malloc(size * sizeof(bh_thread_t));
    pool->size = size;

    if (!pool->threads)
        goto thread_fail;

    /* Initialize queue */
    bh_queue_init(&pool->tasks);
    if (bh_queue_reserve(&pool->tasks, 64))
        goto queue_fail;
    
    /* Initialize threads */
    for (i = 0; i < size; i++)
    {
        if (bh_thread_init(&pool->threads[i], &pool_task))
        {
            pool->shutdown = 1;
            bh_cond_broadcast(&pool->new_task);
            for(; i; i--)
                bh_thread_join(&pool->threads[i - 1]);

            bh_queue_destroy(&pool->tasks);
            goto queue_fail;
        }
    }
    
    return 0;

queue_fail:
    free(pool->threads);

thread_fail:
    bh_cond_destroy(&pool->done_task);

done_fail:
    bh_cond_destroy(&pool->new_task);

task_fail:
    bh_mutex_destroy(&pool->lock);

lock_fail:
    return -1;
}

bh_thread_pool_t *bh_thread_pool_new(size_t size)
{
    bh_thread_pool_t *result;
    result = malloc(sizeof(*result));
    if (result && bh_thread_pool_init(result, size))
    {
        free(result);
        result = NULL;
    }

    return result;
}