/**
 ******************************************************************************
 * @addtogroup PIOS PIOS Core hardware abstraction layer
 * @{
 * @defgroup   PIOS_DEBUGLOG Flash log debugging Functions
 * @brief Debugging functionality
 * @{
 *
 * @file       pios_debuglog.c
 * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2013.
 * @brief      Debugging Functions
 * @see        The GNU Public License (GPL) Version 3
 *
 *****************************************************************************/
/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that 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.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

/* Project Includes */
#include "pios.h"
#include "uavobjectmanager.h"
#include "debuglogentry.h"
#include "callbackinfo.h"

// global definitions
#ifdef PIOS_INCLUDE_DEBUGLOG

// Global variables
extern uintptr_t pios_user_fs_id; // flash filesystem for logging

static xSemaphoreHandle mutex = 0;
#define mutexlock()   xSemaphoreTakeRecursive(mutex, portMAX_DELAY)
#define mutexunlock() xSemaphoreGiveRecursive(mutex)

static bool logging_enabled = false;
#define MAX_CONSECUTIVE_FAILS_COUNT 10
static bool log_is_full     = false;
static uint8_t fails_count  = 0;
static uint16_t flightnum   = 0;
static uint16_t lognum = 0;

#define BUFFERS_COUNT 2
static DebugLogEntryData *current_buffer = 0;
static DebugLogEntryData *buffers[BUFFERS_COUNT] = { 0, 0 };
static uint8_t current_write_buffer_index;
static uint8_t next_read_buffer_index;

#define LOG_ENTRY_MAX_DATA_SIZE (sizeof(((DebugLogEntryData *)0)->Data))
#define LOG_ENTRY_HEADER_SIZE   (sizeof(DebugLogEntryData) - LOG_ENTRY_MAX_DATA_SIZE)
// build the obj_id as a DEBUGLOGENTRY ID with least significant byte zeroed and filled with flight number
#define LOG_GET_FLIGHT_OBJID(x) ((DEBUGLOGENTRY_OBJID & ~0xFF) | (x & 0xFF))

static uint32_t used_buffer_space = 0;

#define CBTASK_PRIORITY   CALLBACK_TASK_AUXILIARY
#define CALLBACK_PRIORITY CALLBACK_PRIORITY_LOW
#define CB_TIMEOUT        100
#define STACK_SIZE_BYTES  512
static DelayedCallbackInfo *callbackHandle;

/* Private Function Prototypes */
static void enqueue_data(uint32_t objid, uint16_t instid, size_t size, uint8_t *data);
static bool write_current_buffer();
static void writeTask();
static uint8_t get_blocks_free();
/**
 * @brief Initialize the log facility
 */
void PIOS_DEBUGLOG_Initialize()
{
    if (!mutex) {
        mutex = xSemaphoreCreateRecursiveMutex();
        for (uint32_t i = 0; i < BUFFERS_COUNT; i++) {
            buffers[i] = pios_malloc(sizeof(DebugLogEntryData));
        }
        current_write_buffer_index = 0;
        next_read_buffer_index     = 0;
        current_buffer = buffers[current_write_buffer_index];
    }

    if (!current_buffer) {
        return;
    }
    mutexlock();
    lognum      = 0;
    flightnum   = 0;
    fails_count = 0;
    used_buffer_space = 0;
    log_is_full = false;
    while (PIOS_FLASHFS_ObjLoad(pios_user_fs_id, LOG_GET_FLIGHT_OBJID(flightnum), lognum, (uint8_t *)current_buffer, sizeof(DebugLogEntryData)) == 0) {
        flightnum++;
    }
    mutexunlock();
    callbackHandle = PIOS_CALLBACKSCHEDULER_Create(&writeTask, CALLBACK_PRIORITY, CBTASK_PRIORITY, CALLBACKINFO_RUNNING_DEBUGLOG, STACK_SIZE_BYTES);
    PIOS_CALLBACKSCHEDULER_Schedule(callbackHandle, CB_TIMEOUT, CALLBACK_UPDATEMODE_LATER);
}


/**
 * @brief Enables or Disables logging globally
 * @param[in] enable or disable logging
 */
void PIOS_DEBUGLOG_Enable(uint8_t enabled)
{
    // increase the flight num as soon as logging is disabled
    if (logging_enabled && !enabled) {
        flightnum++;
        lognum = 0;
    }
    logging_enabled = enabled;
}

/**
 * @brief Write a debug log entry with a uavobject
 * @param[in] objectid
 * @param[in] instanceid
 * @param[in] instanceid
 * @param[in] size of object
 * @param[in] data buffer
 */
void PIOS_DEBUGLOG_UAVObject(uint32_t objid, uint16_t instid, size_t size, uint8_t *data)
{
    if (!logging_enabled || !current_buffer || log_is_full) {
        return;
    }
    mutexlock();

    enqueue_data(objid, instid, size, data);

    mutexunlock();
}
/**
 * @brief Write a debug log entry with text
 * @param[in] format - as in printf
 * @param[in] variable arguments for printf
 * @param...
 */
void PIOS_DEBUGLOG_Printf(char *format, ...)
{
    if (!logging_enabled || !current_buffer || log_is_full) {
        return;
    }

    va_list args;
    va_start(args, format);
    mutexlock();
    // flush any pending buffer before writing debug text
    if (used_buffer_space) {
        write_current_buffer();
    }
    memset(current_buffer->Data, 0xff, sizeof(current_buffer->Data));
    vsnprintf((char *)current_buffer->Data, sizeof(current_buffer->Data), (char *)format, args);
    current_buffer->Flight     = flightnum;

    current_buffer->FlightTime = PIOS_DELAY_GetuS();

    current_buffer->Entry      = lognum;
    current_buffer->Type       = DEBUGLOGENTRY_TYPE_TEXT;
    current_buffer->ObjectID   = 0;
    current_buffer->InstanceID = 0;
    current_buffer->Size       = strlen((const char *)current_buffer->Data);

    if (PIOS_FLASHFS_ObjSave(pios_user_fs_id, LOG_GET_FLIGHT_OBJID(flightnum), lognum, (uint8_t *)current_buffer, sizeof(DebugLogEntryData)) == 0) {
        lognum++;
    }
    mutexunlock();
}


/**
 * @brief Load one object instance from the filesystem
 * @param[out] buffer where to store the uavobject
 * @param[in] log entry from which flight
 * @param[in] log entry sequence number
 * @return 0 if success or error code
 * @retval -1 if fs_id is not a valid filesystem instance
 * @retval -2 if failed to start transaction
 * @retval -3 if object not found in filesystem
 * @retval -4 if object size in filesystem does not exactly match buffer size
 * @retval -5 if reading the object data from flash fails
 */
int32_t PIOS_DEBUGLOG_Read(void *mybuffer, uint16_t flight, uint16_t inst)
{
    PIOS_Assert(mybuffer);
    return PIOS_FLASHFS_ObjLoad(pios_user_fs_id, LOG_GET_FLIGHT_OBJID(flight), inst, (uint8_t *)mybuffer, sizeof(DebugLogEntryData));
}

/**
 * @brief Retrieve run time info of logging system
 * @param[out] current flight number
 * @param[out] next entry number
 * @param[out] free slots in filesystem
 * @param[out] used slots in filesystem
 */
void PIOS_DEBUGLOG_Info(uint16_t *flight, uint16_t *entry, uint16_t *free, uint16_t *used)
{
    if (flight) {
        *flight = flightnum;
    }
    if (entry) {
        *entry = lognum;
    }
    struct PIOS_FLASHFS_Stats stats = { 0, 0 };
    PIOS_FLASHFS_GetStats(pios_user_fs_id, &stats);
    if (free) {
        *free = stats.num_free_slots;
    }
    if (used) {
        *used = stats.num_active_slots;
    }
}

/**
 * @brief Format entire flash memory!!!
 */
void PIOS_DEBUGLOG_Format(void)
{
    mutexlock();
    PIOS_FLASHFS_Format(pios_user_fs_id);
    lognum      = 0;
    flightnum   = 0;
    log_is_full = false;
    fails_count = 0;
    used_buffer_space = 0;
    mutexunlock();
}

void enqueue_data(uint32_t objid, uint16_t instid, size_t size, uint8_t *data)
{
    DebugLogEntryData *entry;

    // start a new block
    if (!used_buffer_space) {
        entry = current_buffer;
        memset(current_buffer->Data, 0xff, sizeof(current_buffer->Data));
        used_buffer_space += size;
    } else {
        // if an instance is being filled and there is enough space, does enqueues new data.
        if (used_buffer_space + size + LOG_ENTRY_HEADER_SIZE > LOG_ENTRY_MAX_DATA_SIZE) {
            current_buffer->Type = DEBUGLOGENTRY_TYPE_MULTIPLEUAVOBJECTS;
            if (!write_current_buffer()) {
                return;
            }
            entry = current_buffer;
            memset(current_buffer->Data, 0xff, sizeof(current_buffer->Data));
            used_buffer_space += size;
        } else {
            entry = (DebugLogEntryData *)&current_buffer->Data[used_buffer_space];
            used_buffer_space += size + LOG_ENTRY_HEADER_SIZE;
        }
    }

    entry->Flight     = flightnum;
    entry->FlightTime = PIOS_DELAY_GetuS();
    entry->Entry = lognum;
    entry->Type = DEBUGLOGENTRY_TYPE_UAVOBJECT;
    entry->ObjectID   = objid;
    entry->InstanceID = instid;
    if (size > sizeof(current_buffer->Data)) {
        size = sizeof(current_buffer->Data);
    }
    entry->Size = size;

    memcpy(entry->Data, data, size);
}

bool write_current_buffer()
{
    PIOS_CALLBACKSCHEDULER_Dispatch(callbackHandle);
    // Check if queue is full

    if (get_blocks_free() > 0) {
        current_write_buffer_index = (current_write_buffer_index + 1) % BUFFERS_COUNT;
        current_buffer    = buffers[current_write_buffer_index];
        used_buffer_space = 0;
        return true;
    } else {
        return false;
    }
}

static uint8_t get_blocks_free()
{
    uint8_t used_blocks = current_write_buffer_index - next_read_buffer_index;

    if (current_write_buffer_index < next_read_buffer_index) {
        used_blocks = (BUFFERS_COUNT - next_read_buffer_index) + current_write_buffer_index;
    }
    return (BUFFERS_COUNT - used_blocks) - 1;
}

static void writeTask()
{
    if (current_write_buffer_index != next_read_buffer_index) {
        // not enough space, write the block and start a new one
        if (PIOS_FLASHFS_ObjSave(pios_user_fs_id,
                                 LOG_GET_FLIGHT_OBJID(flightnum), lognum,
                                 (uint8_t *)buffers[next_read_buffer_index],
                                 sizeof(DebugLogEntryData)) == 0) {
            next_read_buffer_index = (next_read_buffer_index + 1) % BUFFERS_COUNT;
            lognum++;
            fails_count = 0;
        } else {
            if (fails_count++ > MAX_CONSECUTIVE_FAILS_COUNT) {
                log_is_full = true;
            }
        }
    }
}
#endif /* ifdef PIOS_INCLUDE_DEBUGLOG */
/**
 * @}
 * @}
 */