/*******************************************************************************

  Eurecom OpenAirInterface
  Copyright(c) 1999 - 2012 Eurecom

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

  This program is distributed in the hope 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, write to the Free Software Foundation, Inc.,
  51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.

  The full GNU General Public License is included in this distribution in
  the file called "COPYING".

  Contact Information
  Openair Admin: openair_admin@eurecom.fr
  Openair Tech : openair_tech@eurecom.fr
  Forums       : http://forums.eurecom.fr/openairinterface
  Address      : EURECOM, Campus SophiaTech, 450 Route des Chappes
                 06410 Biot FRANCE

*******************************************************************************/

#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>

#include "queue.h"
#include "assertions.h"

#include "intertask_interface.h"
#include "intertask_interface_dump.h"
/* Includes "intertask_interface_init.h" to check prototype coherence, but disable threads and messages information generation */
#define CHECK_PROTOTYPE_ONLY
#include "intertask_interface_init.h"
#undef CHECK_PROTOTYPE_ONLY

#include "timer.h"

int itti_debug = 1;

#define ITTI_DEBUG(x, args...) do { if (itti_debug) fprintf(stdout, "[ITTI][D]"x, ##args); } \
    while(0)
#define ITTI_ERROR(x, args...) do { fprintf(stdout, "[ITTI][E]"x, ##args); } \
    while(0)

/* Global message size */
#define MESSAGE_SIZE(mESSAGEiD) (sizeof(MessageHeader) + itti_desc.messages_info[mESSAGEiD].size)

typedef enum task_state_s {
    TASK_STATE_NOT_CONFIGURED,
    TASK_STATE_STARTING,
    TASK_STATE_READY,
    TASK_STATE_MAX,
} task_state_t;

/* This list acts as a FIFO of messages received by tasks (RRC, NAS, ...) */
struct message_list_s {
    STAILQ_ENTRY(message_list_s) next_element;

    MessageDef *msg;          ///< Pointer to the message

    message_number_t message_number;  ///< Unique message number
    uint32_t message_priority;        ///< Message priority
};

typedef struct task_desc_s {
    /* Queue of messages belonging to the task */
    STAILQ_HEAD(message_queue_head, message_list_s) message_queue;

    /* Number of messages in the queue */
    volatile uint32_t   message_in_queue;
    /* Mutex for the message queue */
    pthread_mutex_t     message_queue_mutex;
    /* Conditional var for message queue and task synchro */
    pthread_cond_t      message_queue_cond_var;
    pthread_t           task_thread;
    volatile task_state_t task_state;
} task_desc_t;

struct itti_desc_s {
    task_desc_t *tasks;
    /* Current message number. Incremented every call to send_msg_to_task */
    message_number_t   message_number __attribute__((aligned(8)));

    thread_id_t thread_max;
    MessagesIds messages_id_max;

    const char * const *threads_name;
    const message_info_t *messages_info;
};

static struct itti_desc_s itti_desc;

static inline
message_number_t increment_message_number(void)
{
    /* Atomic operation supported by GCC: returns the current message number
     * and then increment it by 1.
     * This can be done without mutex.
     */
    return __sync_fetch_and_add(&itti_desc.message_number, 1);
}

static inline uint32_t get_message_priority(MessagesIds message_id)
{
    DevCheck(message_id < itti_desc.messages_id_max, message_id, itti_desc.messages_id_max, 0);

    return (itti_desc.messages_info[message_id].priority);
}

char *get_message_name(MessagesIds message_id)
{
    DevCheck(message_id < itti_desc.messages_id_max, message_id, itti_desc.messages_id_max, 0);

    return (itti_desc.messages_info[message_id].name);
}

int send_broadcast_message(MessageDef *message_p)
{
    uint32_t i;
    int ret = 0;
    int temp;

    for (i = THREAD_FIRST; i < itti_desc.thread_max; i++)
    {
        MessageDef *new_message_p;

        /* Skip tasks which are not running */
        if (itti_desc.tasks[i].task_state != TASK_STATE_READY)
            continue;

        new_message_p = malloc(sizeof(MessageDef));

        if (new_message_p == NULL) {
            ITTI_ERROR("Failed to allocate memory (%s:%d)\n",
                       __FILE__, __LINE__);
            return -1;
        }
        memcpy(new_message_p, message_p, sizeof(MessageDef));
        temp = send_msg_to_task(i, INSTANCE_DEFAULT, new_message_p);
        if (temp < 0) {
            ITTI_ERROR("Failed to send broadcast message (%s) to queue (%u:%s)\n",
                       itti_desc.messages_info[message_p->header.messageId].name, i, itti_desc.threads_name[i]);
            ret = temp;
            free(new_message_p);
        }
    }

    return ret;
}

inline MessageDef *alloc_new_message(
    task_id_t      origin_task_id,
    MessagesIds message_id)
{
    MessageDef *temp = NULL;

    if ((TASK_GET_THREAD_ID(origin_task_id) >= itti_desc.thread_max) ||
        (message_id >= itti_desc.messages_id_max))
    {
        return NULL;
    }

    temp = calloc(1, MESSAGE_SIZE(message_id));

    if (temp == NULL) {
        ITTI_ERROR("Cannot allocate memory for new message (%s:%d)\n",
                   __FILE__, __LINE__);
        return NULL;
    }

    temp->header.messageId = message_id;
    temp->header.originTaskId = origin_task_id;
    temp->header.size = itti_desc.messages_info[message_id].size;

    return temp;
}

int send_msg_to_task(task_id_t task_id, instance_t instance, MessageDef *message)
{
    thread_id_t             thread_id = TASK_GET_THREAD_ID(task_id);
    struct message_list_s  *new;
    uint32_t                priority;
    message_number_t        message_number;
    uint32_t                message_id;

    if (thread_id >= itti_desc.thread_max)
    {
        return -1;
    }

    message->header.destinationTaskId = task_id;
    message->header.instance = instance;
    message_id = message->header.messageId;

    DevAssert(message != NULL);
    DevCheck(thread_id < itti_desc.thread_max, thread_id, 0, 0);
    DevCheck(message_id < itti_desc.messages_id_max, itti_desc.messages_id_max, message_id, 0);

    priority = get_message_priority(message_id);

    /* Lock the mutex to get exclusive access to the list */
    pthread_mutex_lock(&itti_desc.tasks[thread_id].message_queue_mutex);

    /* We cannot send a message if the task is not running */
    DevCheck(itti_desc.tasks[thread_id].task_state == TASK_STATE_READY,
             itti_desc.tasks[thread_id].task_state, TASK_STATE_READY, thread_id);

    /* Check the number of messages in the queue */
    DevCheck((itti_desc.tasks[thread_id].message_in_queue * sizeof(MessageDef))
             < ITTI_QUEUE_SIZE_PER_TASK,
             (itti_desc.tasks[thread_id].message_in_queue * sizeof(MessageDef)),
             ITTI_QUEUE_SIZE_PER_TASK,
             itti_desc.tasks[thread_id].message_in_queue);

    /* Allocate new list element */
    if ((new = (struct message_list_s *)malloc(sizeof(struct message_list_s))) == NULL)
    {
        ITTI_ERROR("Cannot allocate memory for new message (%s:%d)\n",
                   __FILE__, __LINE__);
        return -1;
    }

    /* Increment the global message number */
    message_number = increment_message_number();

    /* Fill in members */
    new->msg              = message;
    new->message_number   = message_number;
    new->message_priority = priority;

    itti_dump_queue_message(message_number, message, itti_desc.messages_info[message_id].name, MESSAGE_SIZE(message_id));

    if (STAILQ_EMPTY(&itti_desc.tasks[thread_id].message_queue)) {
        STAILQ_INSERT_HEAD(&itti_desc.tasks[thread_id].message_queue, new, next_element);
    } else {
//         struct message_list_s *insert_after = NULL;
//         struct message_list_s *temp;
// 
//         /* This method is inefficient... */
//         STAILQ_FOREACH(temp, &itti_desc.tasks[thread_id].message_queue, next_element) {
//             struct message_list_s *next;
//             next = STAILQ_NEXT(temp, next_element);
//             /* Increment message priority to create a sort of
//              * priority based scheduler */
// //             if (temp->message_priority < TASK_PRIORITY_MAX) {
// //                 temp->message_priority++;
// //             }
//             if (next && next->message_priority < priority) {
//                 insert_after = temp;
//                 break;
//             }
//         }
//         if (insert_after == NULL) {
            STAILQ_INSERT_TAIL(&itti_desc.tasks[thread_id].message_queue, new, next_element);
//         } else {
//             STAILQ_INSERT_AFTER(&itti_desc.tasks[thread_id].message_queue, insert_after, new,
//                                 next_element);
//         }
    }

    /* Update the number of messages in the queue */
    itti_desc.tasks[thread_id].message_in_queue++;
    if (itti_desc.tasks[thread_id].message_in_queue == 1) {
        /* Emit a signal to wake up target task thread */
        pthread_cond_signal(&itti_desc.tasks[thread_id].message_queue_cond_var);
    }
    /* Release the mutex */
    pthread_mutex_unlock(&itti_desc.tasks[thread_id].message_queue_mutex);
    ITTI_DEBUG("Message %s, number %lu with priority %d successfully sent to queue (%u:%s)\n",
               itti_desc.messages_info[message_id].name, message_number,
               priority, thread_id, itti_desc.threads_name[thread_id]);
    return 0;
}

void receive_msg(task_id_t task_id, MessageDef **received_msg)
{
    thread_id_t thread_id = TASK_GET_THREAD_ID(task_id);

    DevCheck(thread_id < itti_desc.thread_max, thread_id, 0, 0);
    DevAssert(received_msg != NULL);

    // Lock the mutex to get exclusive access to the list
    pthread_mutex_lock(&itti_desc.tasks[thread_id].message_queue_mutex);

    if (itti_desc.tasks[thread_id].message_in_queue == 0) {
        ITTI_DEBUG("Message in queue[(%u:%s)] == 0, waiting\n",
                   thread_id, itti_desc.threads_name[thread_id]);
        // Wait while list == 0
        pthread_cond_wait(&itti_desc.tasks[thread_id].message_queue_cond_var,
                          &itti_desc.tasks[thread_id].message_queue_mutex);
        ITTI_DEBUG("Receiver queue[(%u:%s)] got new message notification for task %x\n",
                   thread_id, itti_desc.threads_name[thread_id], task_id);
    }

    if (!STAILQ_EMPTY(&itti_desc.tasks[thread_id].message_queue)) {
        struct message_list_s *temp = STAILQ_FIRST(
                                          &itti_desc.tasks[thread_id].message_queue);

        /* Update received_msg reference */
        *received_msg = temp->msg;

        /* Remove message from queue */
        STAILQ_REMOVE_HEAD(&itti_desc.tasks[thread_id].message_queue, next_element);
        free(temp);
        itti_desc.tasks[thread_id].message_in_queue--;
    }
    // Release the mutex
    pthread_mutex_unlock(&itti_desc.tasks[thread_id].message_queue_mutex);
}

void poll_msg(task_id_t task_id, instance_t instance, MessageDef **received_msg)
{
    thread_id_t thread_id = TASK_GET_THREAD_ID(task_id);

    DevCheck (thread_id < itti_desc.thread_max, thread_id, 0, 0);
    DevAssert (received_msg != NULL);

    *received_msg = NULL;

    if (itti_desc.tasks[thread_id].message_in_queue != 0)
    {
        struct message_list_s *temp;

        // Lock the mutex to get exclusive access to the list
        pthread_mutex_lock (&itti_desc.tasks[thread_id].message_queue_mutex);

        STAILQ_FOREACH(temp, &itti_desc.tasks[thread_id].message_queue, next_element)
        {
            if ((temp->msg->header.destinationTaskId == task_id)
                    && ((instance == INSTANCE_ALL) || (temp->msg->header.instance == instance)))
            {
                /* Update received_msg reference */
                *received_msg = temp->msg;

                /* Remove message from queue */
                STAILQ_REMOVE(&itti_desc.tasks[thread_id].message_queue, temp, message_list_s, next_element);
                free (temp);
                itti_desc.tasks[thread_id].message_in_queue--;

                ITTI_DEBUG("Receiver queue[(%u:%s)] got new message %s, number %lu for task %x\n",
                           thread_id, itti_desc.threads_name[thread_id], itti_desc.messages_info[temp->msg->header.messageId].name,
                           temp->message_number, task_id);
                break;
            }
        }

        // Release the mutex
        pthread_mutex_unlock (&itti_desc.tasks[thread_id].message_queue_mutex);
    }

    if (*received_msg == NULL)
    {
        ITTI_DEBUG("No message in queue[(%u:%s)] for task %x\n", thread_id, itti_desc.threads_name[thread_id], task_id);
    }
}

int intertask_interface_create_task(task_id_t task_id,
                                    void *(*start_routine) (void *),
                                    void *args_p)
{
    thread_id_t thread_id = TASK_GET_THREAD_ID(task_id);

    DevAssert(start_routine != NULL);
    DevCheck(thread_id < itti_desc.thread_max, thread_id, 0, 0);

    if (itti_desc.tasks[thread_id].task_state != TASK_STATE_NOT_CONFIGURED) {
        ITTI_ERROR("You are attempting to start an already configured thread"
                   " for %s thread\n", itti_desc.threads_name[thread_id]);
        return -1;
    }

    itti_desc.tasks[thread_id].task_state = TASK_STATE_STARTING;

    if (pthread_create(&itti_desc.tasks[thread_id].task_thread, NULL, start_routine,
                       args_p) < 0) {
        ITTI_ERROR("Failed to initialize %s thread: %s:%d\n", itti_desc.threads_name[thread_id],
                   strerror(errno),
                   errno);
        return -1;
    }

    /* Wait till the thread is completely ready */
    while (itti_desc.tasks[thread_id].task_state != TASK_STATE_READY);
    return 0;
}

void intertask_interface_mark_task_ready(task_id_t task_id)
{
    thread_id_t thread_id = TASK_GET_THREAD_ID(task_id);

    DevCheck(thread_id < itti_desc.thread_max, thread_id, 0, 0);
    // Lock the mutex to get exclusive access to the list
    pthread_mutex_lock(&itti_desc.tasks[thread_id].message_queue_mutex);
    itti_desc.tasks[thread_id].task_state = TASK_STATE_READY;
    // Release the mutex
    pthread_mutex_unlock(&itti_desc.tasks[thread_id].message_queue_mutex);
}

int intertask_interface_init(thread_id_t thread_max, MessagesIds messages_id_max,
                             const char * const *threads_name,
                             const message_info_t *messages_info,
                             const char * const messages_definition_xml)
{
    int i;
    itti_desc.message_number = 0;

    /* Saves threads and messages max values */
    itti_desc.thread_max = thread_max;
    itti_desc.messages_id_max = messages_id_max;
    itti_desc.threads_name = threads_name;
    itti_desc.messages_info = messages_info;

    /* Allocates memory for tasks info */
    itti_desc.tasks = calloc(itti_desc.thread_max, sizeof(task_desc_t));

    /* Initializing each queue and related stuff */
    for (i = THREAD_FIRST; i < itti_desc.thread_max; i++) {
        STAILQ_INIT(&itti_desc.tasks[i].message_queue);
        itti_desc.tasks[i].message_in_queue = 0;
        // Initialize mutexes
        pthread_mutex_init(&itti_desc.tasks[i].message_queue_mutex, NULL);
        // Initialize Cond vars
        pthread_cond_init(&itti_desc.tasks[i].message_queue_cond_var, NULL);
        itti_desc.tasks[i].task_state = TASK_STATE_NOT_CONFIGURED;
    }
    itti_dump_init(messages_definition_xml);

    timer_init();

    return 0;
}

void intertask_interface_send_quit_signal(void)
{
    int i;
    MessageDef *terminate_message_p;

    terminate_message_p = alloc_new_message(TASK_UNKNOWN, TERMINATE_MESSAGE);

    send_broadcast_message(terminate_message_p);

    for (i = THREAD_FIRST; i < itti_desc.thread_max; i++) {
        /* Skip tasks which are not running */
        if (itti_desc.tasks[i].task_state != TASK_STATE_READY)
            continue;
    }
}