/*************************************************************************
*
*  Orca
*  Copyright 2023 Martin Fouilleul and the Orca project contributors
*  See LICENSE.txt for licensing information
*
**************************************************************************/
#include <pthread.h>
#include <signal.h> //needed for pthread_kill() on linux
#include <stdlib.h>
#include <string.h>
#include <sys/time.h>
#include <unistd.h> // nanosleep()

#include "platform_thread.h"

struct oc_thread
{
    bool valid;
    pthread_t pthread;
    oc_thread_start_proc start;
    void* userPointer;
    oc_str8 name;
    char nameBuffer[OC_THREAD_NAME_MAX_SIZE];
};

static void* oc_thread_bootstrap(void* data)
{
    oc_thread* thread = (oc_thread*)data;
    if(thread->name.len)
    {
        pthread_setname_np(thread->nameBuffer);
    }
    i32 exitCode = thread->start(thread->userPointer);
    return ((void*)(ptrdiff_t)exitCode);
}

oc_thread* oc_thread_create_with_name(oc_thread_start_proc start, void* userPointer, oc_str8 name)
{
    oc_thread* thread = (oc_thread*)malloc(sizeof(oc_thread));
    if(!thread)
    {
        return (0);
    }

    if(name.len && name.ptr)
    {
        char* end = stpncpy(thread->nameBuffer, name.ptr, oc_min(name.len, OC_THREAD_NAME_MAX_SIZE - 1));
        *end = '\0';
        thread->name = oc_str8_from_buffer(end - thread->nameBuffer, thread->nameBuffer);
    }
    else
    {
        thread->nameBuffer[0] = '\0';
        thread->name = oc_str8_from_buffer(0, thread->nameBuffer);
    }
    thread->start = start;
    thread->userPointer = userPointer;

    if(pthread_create(&thread->pthread, 0, oc_thread_bootstrap, thread) != 0)
    {
        free(thread);
        return (0);
    }
    else
    {
        thread->valid = true;
        return (thread);
    }
}

oc_thread* oc_thread_create(oc_thread_start_proc start, void* userPointer)
{
    return (oc_thread_create_with_name(start, userPointer, (oc_str8){ 0 }));
}

oc_str8 oc_thread_get_name(oc_thread* thread)
{
    return (thread->name);
}

u64 oc_thread_unique_id(oc_thread* thread)
{
    u64 id;
    pthread_threadid_np(thread->pthread, &id);
    return (id);
}

u64 oc_thread_self_id()
{
    pthread_t thread = pthread_self();
    u64 id;
    pthread_threadid_np(thread, &id);
    return (id);
}

int oc_thread_signal(oc_thread* thread, int sig)
{
    return (pthread_kill(thread->pthread, sig));
}

int oc_thread_join(oc_thread* thread, i64* exitCode)
{
    void* ret;
    if(pthread_join(thread->pthread, &ret))
    {
        return (-1);
    }
    free(thread);

    if(exitCode)
    {
        *exitCode = (off_t)ret;
    }
    return (0);
}

int oc_thread_detach(oc_thread* thread)
{
    if(pthread_detach(thread->pthread))
    {
        return (-1);
    }
    free(thread);
    return (0);
}

struct oc_mutex
{
    pthread_mutex_t pmutex;
};

oc_mutex* oc_mutex_create()
{
    oc_mutex* mutex = (oc_mutex*)malloc(sizeof(oc_mutex));
    if(!mutex)
    {
        return (0);
    }
    if(pthread_mutex_init(&mutex->pmutex, 0) != 0)
    {
        free(mutex);
        return (0);
    }
    return (mutex);
}

int oc_mutex_destroy(oc_mutex* mutex)
{
    if(pthread_mutex_destroy(&mutex->pmutex) != 0)
    {
        return (-1);
    }
    free(mutex);
    return (0);
}

int oc_mutex_lock(oc_mutex* mutex)
{
    return (pthread_mutex_lock(&mutex->pmutex));
}

int oc_mutex_unlock(oc_mutex* mutex)
{
    return (pthread_mutex_unlock(&mutex->pmutex));
}

// oc_ticket has a mirrored implementation in win32_thread.c

void oc_ticket_init(oc_ticket* mutex)
{
    mutex->nextTicket = 0;
    mutex->serving = 0;
}

void oc_ticket_lock(oc_ticket* mutex)
{
    u64 ticket = atomic_fetch_add(&mutex->nextTicket, 1ULL);
    while(ticket != mutex->serving)
        ; //spin
}

void oc_ticket_unlock(oc_ticket* mutex)
{
    atomic_fetch_add(&mutex->serving, 1ULL);
}

struct oc_condition
{
    pthread_cond_t pcond;
};

oc_condition* oc_condition_create()
{
    oc_condition* cond = (oc_condition*)malloc(sizeof(oc_condition));
    if(!cond)
    {
        return (0);
    }
    if(pthread_cond_init(&cond->pcond, 0) != 0)
    {
        free(cond);
        return (0);
    }
    return (cond);
}

int oc_condition_destroy(oc_condition* cond)
{
    if(pthread_cond_destroy(&cond->pcond) != 0)
    {
        return (-1);
    }
    free(cond);
    return (0);
}

int oc_condition_wait(oc_condition* cond, oc_mutex* mutex)
{
    return (pthread_cond_wait(&cond->pcond, &mutex->pmutex));
}

int oc_condition_timedwait(oc_condition* cond, oc_mutex* mutex, f64 seconds)
{
    struct timeval tv;
    gettimeofday(&tv, 0);

    i64 iSeconds = (i64)seconds;
    f64 fracSeconds = seconds - (f64)iSeconds;

    struct timespec ts;
    ts.tv_sec = tv.tv_sec + iSeconds;
    ts.tv_nsec = tv.tv_usec * 1000 + (i32)(fracSeconds * 1e9);
    ts.tv_sec += ts.tv_nsec / 1000000000;
    ts.tv_nsec = ts.tv_nsec % 1000000000;

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

int oc_condition_signal(oc_condition* cond)
{
    return (pthread_cond_signal(&cond->pcond));
}

int oc_condition_broadcast(oc_condition* cond)
{
    return (pthread_cond_broadcast(&cond->pcond));
}

void oc_sleep_nano(u64 nanoseconds)
{
    timespec rqtp;
    rqtp.tv_sec = nanoseconds / 1000000000;
    rqtp.tv_nsec = nanoseconds - rqtp.tv_sec * 1000000000;
    nanosleep(&rqtp, 0);
}