/*
 * This file 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 file 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, see <http://www.gnu.org/licenses/>.
 * 
 * Code by Andrew Tridgell and Siddharth Bharat Purohit
 */
#include <AP_HAL/AP_HAL.h>

#include "AP_HAL_ChibiOS.h"
#include "Scheduler.h"
#include "Util.h"

#include <AP_HAL_ChibiOS/UARTDriver.h>
#include <AP_HAL_ChibiOS/AnalogIn.h>
#include <AP_HAL_ChibiOS/Storage.h>
#include <AP_HAL_ChibiOS/RCOutput.h>
#include <AP_HAL_ChibiOS/RCInput.h>
#include <AP_HAL_ChibiOS/CAN.h>

#if CH_CFG_USE_DYNAMIC == TRUE

#include <AP_Logger/AP_Logger.h>
#include <AP_Scheduler/AP_Scheduler.h>
#include <AP_BoardConfig/AP_BoardConfig.h>
#include "hwdef/common/stm32_util.h"
#include "hwdef/common/watchdog.h"
#include "shared_dma.h"
#include "sdcard.h"

#if HAL_WITH_IO_MCU
#include <AP_IOMCU/AP_IOMCU.h>
extern AP_IOMCU iomcu;
#endif

using namespace ChibiOS;

extern const AP_HAL::HAL& hal;
#ifndef HAL_NO_TIMER_THREAD
THD_WORKING_AREA(_timer_thread_wa, TIMER_THD_WA_SIZE);
#endif
#ifndef HAL_NO_RCIN_THREAD
THD_WORKING_AREA(_rcin_thread_wa, RCIN_THD_WA_SIZE);
#endif
#ifndef HAL_USE_EMPTY_IO
THD_WORKING_AREA(_io_thread_wa, IO_THD_WA_SIZE);
#endif
#ifndef HAL_USE_EMPTY_STORAGE
THD_WORKING_AREA(_storage_thread_wa, STORAGE_THD_WA_SIZE);
#endif
Scheduler::Scheduler()
{
}

void Scheduler::init()
{
    chBSemObjectInit(&_timer_semaphore, false);
    chBSemObjectInit(&_io_semaphore, false);

#ifndef HAL_NO_TIMER_THREAD
    // setup the timer thread - this will call tasks at 1kHz
    _timer_thread_ctx = chThdCreateStatic(_timer_thread_wa,
                     sizeof(_timer_thread_wa),
                     APM_TIMER_PRIORITY,        /* Initial priority.    */
                     _timer_thread,             /* Thread function.     */
                     this);                     /* Thread parameter.    */
#endif

#ifndef HAL_NO_RCIN_THREAD
    // setup the RCIN thread - this will call tasks at 1kHz
    _rcin_thread_ctx = chThdCreateStatic(_rcin_thread_wa,
                     sizeof(_rcin_thread_wa),
                     APM_RCIN_PRIORITY,        /* Initial priority.    */
                     _rcin_thread,             /* Thread function.     */
                     this);                     /* Thread parameter.    */
#endif
#ifndef HAL_USE_EMPTY_IO
    // the IO thread runs at lower priority
    _io_thread_ctx = chThdCreateStatic(_io_thread_wa,
                     sizeof(_io_thread_wa),
                     APM_IO_PRIORITY,        /* Initial priority.      */
                     _io_thread,             /* Thread function.       */
                     this);                  /* Thread parameter.      */
#endif

#ifndef HAL_USE_EMPTY_STORAGE
    // the storage thread runs at just above IO priority
    _storage_thread_ctx = chThdCreateStatic(_storage_thread_wa,
                     sizeof(_storage_thread_wa),
                     APM_STORAGE_PRIORITY,        /* Initial priority.      */
                     _storage_thread,             /* Thread function.       */
                     this);                  /* Thread parameter.      */
#endif

}


void Scheduler::delay_microseconds(uint16_t usec)
{
    if (usec == 0) { //chibios faults with 0us sleep
        return;
    }
    uint32_t ticks;
    ticks = chTimeUS2I(usec);
    if (ticks == 0) {
        // calling with ticks == 0 causes a hard fault on ChibiOS
        ticks = 1;
    }
    chThdSleep(ticks); //Suspends Thread for desired microseconds
}

/*
  wrapper around sem_post that boosts main thread priority
 */
static void set_high_priority()
{
#if APM_MAIN_PRIORITY_BOOST != APM_MAIN_PRIORITY
    hal_chibios_set_priority(APM_MAIN_PRIORITY_BOOST);
#endif
}

/*
  return the main thread to normal priority
 */
void Scheduler::boost_end(void)
{
#if APM_MAIN_PRIORITY_BOOST != APM_MAIN_PRIORITY
    if (in_main_thread() && _priority_boosted) {
        _priority_boosted = false;
        hal_chibios_set_priority(APM_MAIN_PRIORITY);
    }
#endif
}

/*
  a variant of delay_microseconds that boosts priority to
  APM_MAIN_PRIORITY_BOOST for APM_MAIN_PRIORITY_BOOST_USEC
  microseconds when the time completes. This significantly improves
  the regularity of timing of the main loop
 */
void Scheduler::delay_microseconds_boost(uint16_t usec)
{
    if (in_main_thread()) {
        set_high_priority();
        _priority_boosted = true;
    }
    delay_microseconds(usec); //Suspends Thread for desired microseconds
    _called_boost = true;
}

/*
  return true if delay_microseconds_boost() has been called since last check
 */
bool Scheduler::check_called_boost(void)
{
    if (!_called_boost) {
        return false;
    }
    _called_boost = false;
    return true;
}

void Scheduler::delay(uint16_t ms)
{
    uint64_t start = AP_HAL::micros64();

    while ((AP_HAL::micros64() - start)/1000 < ms) {
        delay_microseconds(1000);
        if (_min_delay_cb_ms <= ms) {
            if (in_main_thread()) {
                call_delay_cb();
            }
        }
    }
}

void Scheduler::register_timer_process(AP_HAL::MemberProc proc)
{
    chBSemWait(&_timer_semaphore);
    for (uint8_t i = 0; i < _num_timer_procs; i++) {
        if (_timer_proc[i] == proc) {
            chBSemSignal(&_timer_semaphore);
            return;
        }
    }

    if (_num_timer_procs < CHIBIOS_SCHEDULER_MAX_TIMER_PROCS) {
        _timer_proc[_num_timer_procs] = proc;
        _num_timer_procs++;
    } else {
        hal.console->printf("Out of timer processes\n");
    }
    chBSemSignal(&_timer_semaphore);
}

void Scheduler::register_io_process(AP_HAL::MemberProc proc)
{
    chBSemWait(&_io_semaphore);
    for (uint8_t i = 0; i < _num_io_procs; i++) {
        if (_io_proc[i] == proc) {
            chBSemSignal(&_io_semaphore);
            return;
        }
    }
    
    if (_num_io_procs < CHIBIOS_SCHEDULER_MAX_TIMER_PROCS) {
        _io_proc[_num_io_procs] = proc;
        _num_io_procs++;
    } else {
        hal.console->printf("Out of IO processes\n");
    }
    chBSemSignal(&_io_semaphore);
}

void Scheduler::register_timer_failsafe(AP_HAL::Proc failsafe, uint32_t period_us)
{
    _failsafe = failsafe;
}

void Scheduler::reboot(bool hold_in_bootloader)
{
    // disarm motors to ensure they are off during a bootloader upload
    hal.rcout->force_safety_on();

#if HAL_WITH_IO_MCU
    if (AP_BoardConfig::io_enabled()) {
        iomcu.shutdown();
    }
#endif

#ifndef NO_LOGGING
    //stop logging
    if (AP_Logger::get_singleton()) {
        AP::logger().StopLogging();
    }

    // stop sdcard driver, if active
    sdcard_stop();
#endif

#if defined(HAL_USE_RTC) && HAL_USE_RTC
    // setup RTC for fast reboot
    set_fast_reboot(hold_in_bootloader?RTC_BOOT_HOLD:RTC_BOOT_FAST);
#endif

    // disable all interrupt sources
    port_disable();
    
    // reboot
    NVIC_SystemReset();
}

void Scheduler::_run_timers()
{
    if (_in_timer_proc) {
        return;
    }
    _in_timer_proc = true;

    int num_procs = 0;
    chBSemWait(&_timer_semaphore);
    num_procs = _num_timer_procs;
    chBSemSignal(&_timer_semaphore);
    // now call the timer based drivers
    for (int i = 0; i < num_procs; i++) {
        if (_timer_proc[i]) {
            _timer_proc[i]();
        }
    }

    // and the failsafe, if one is setup
    if (_failsafe != nullptr) {
        _failsafe();
    }

#if HAL_USE_ADC == TRUE && !defined(HAL_DISABLE_ADC_DRIVER)
    // process analog input
    ((AnalogIn *)hal.analogin)->_timer_tick();
#endif

    _in_timer_proc = false;
}

void Scheduler::_timer_thread(void *arg)
{
    Scheduler *sched = (Scheduler *)arg;
    chRegSetThreadName("apm_timer");

    while (!sched->_hal_initialized) {
        sched->delay_microseconds(1000);
    }
    while (true) {
        sched->delay_microseconds(1000);

        // run registered timers
        sched->_run_timers();

        // process any pending RC output requests
        hal.rcout->timer_tick();

        if (sched->expect_delay_start != 0) {
            uint32_t now = AP_HAL::millis();
            if (now - sched->expect_delay_start <= sched->expect_delay_length) {
                stm32_watchdog_pat();
            }
        }
    }
}

void Scheduler::_rcin_thread(void *arg)
{
    Scheduler *sched = (Scheduler *)arg;
    chRegSetThreadName("apm_rcin");
    while (!sched->_hal_initialized) {
        sched->delay_microseconds(20000);
    }
    while (true) {
        sched->delay_microseconds(2500);
        ((RCInput *)hal.rcin)->_timer_tick();
    }
}

void Scheduler::_run_io(void)
{
    if (_in_io_proc) {
        return;
    }
    _in_io_proc = true;

    int num_procs = 0;
    chBSemWait(&_io_semaphore);
    num_procs = _num_io_procs;
    chBSemSignal(&_io_semaphore);
    // now call the IO based drivers
    for (int i = 0; i < num_procs; i++) {
        if (_io_proc[i]) {
            _io_proc[i]();
        }
    }

    _in_io_proc = false;
}

void Scheduler::_io_thread(void* arg)
{
    Scheduler *sched = (Scheduler *)arg;
    chRegSetThreadName("apm_io");
    while (!sched->_hal_initialized) {
        sched->delay_microseconds(1000);
    }
    uint32_t last_sd_start_ms = AP_HAL::millis();
    while (true) {
        sched->delay_microseconds(1000);

        // run registered IO processes
        sched->_run_io();

        if (!hal.util->get_soft_armed()) {
            // if sdcard hasn't mounted then retry it every 3s in the IO
            // thread when disarmed
            uint32_t now = AP_HAL::millis();
            if (now - last_sd_start_ms > 3000) {
                last_sd_start_ms = now;
                sdcard_retry();
            }
        }
    }
}

void Scheduler::_storage_thread(void* arg)
{
    Scheduler *sched = (Scheduler *)arg;
    chRegSetThreadName("apm_storage");
    while (!sched->_hal_initialized) {
        sched->delay_microseconds(10000);
    }
    while (true) {
        sched->delay_microseconds(10000);

        // process any pending storage writes
        hal.storage->_timer_tick();
    }
}

bool Scheduler::in_main_thread() const
{
    return get_main_thread() == chThdGetSelfX();
}

void Scheduler::system_initialized()
{
    if (_initialized) {
        AP_HAL::panic("PANIC: scheduler::system_initialized called"
                      "more than once");
    }
    _initialized = true;
}

/*
  disable interrupts and return a context that can be used to
  restore the interrupt state. This can be used to protect
  critical regions
*/
void *Scheduler::disable_interrupts_save(void)
{
    return (void *)(uintptr_t)chSysGetStatusAndLockX();
}

/*
  restore interrupt state from disable_interrupts_save()
*/
void Scheduler::restore_interrupts(void *state)
{
    chSysRestoreStatusX((syssts_t)(uintptr_t)state);
}

/*
  trampoline for thread create
*/
void Scheduler::thread_create_trampoline(void *ctx)
{
    AP_HAL::MemberProc *t = (AP_HAL::MemberProc *)ctx;
    (*t)();
    free(t);
}

/*
  create a new thread
*/
bool Scheduler::thread_create(AP_HAL::MemberProc proc, const char *name, uint32_t stack_size, priority_base base, int8_t priority)
{
    // take a copy of the MemberProc, it is freed after thread exits
    AP_HAL::MemberProc *tproc = (AP_HAL::MemberProc *)malloc(sizeof(proc));
    if (!tproc) {
        return false;
    }
    *tproc = proc;

    uint8_t thread_priority = APM_IO_PRIORITY;
    static const struct {
        priority_base base;
        uint8_t p;
    } priority_map[] = {
        { PRIORITY_BOOST, APM_MAIN_PRIORITY_BOOST},
        { PRIORITY_MAIN, APM_MAIN_PRIORITY},
        { PRIORITY_SPI, APM_SPI_PRIORITY},
        { PRIORITY_I2C, APM_I2C_PRIORITY},
        { PRIORITY_CAN, APM_CAN_PRIORITY},
        { PRIORITY_TIMER, APM_TIMER_PRIORITY},
        { PRIORITY_RCIN, APM_RCIN_PRIORITY},
        { PRIORITY_IO, APM_IO_PRIORITY},
        { PRIORITY_UART, APM_UART_PRIORITY},
        { PRIORITY_STORAGE, APM_STORAGE_PRIORITY},
        { PRIORITY_SCRIPTING, APM_SCRIPTING_PRIORITY},
    };
    for (uint8_t i=0; i<ARRAY_SIZE(priority_map); i++) {
        if (priority_map[i].base == base) {
            thread_priority = constrain_int16(priority_map[i].p + priority, LOWPRIO, HIGHPRIO);
            break;
        }
    }
    thread_t *thread_ctx = thread_create_alloc(THD_WORKING_AREA_SIZE(stack_size),
                                               name,
                                               thread_priority,
                                               thread_create_trampoline,
                                               tproc);
    if (thread_ctx == nullptr) {
        free(tproc);
        return false;
    }
    return true;
}

/*
  inform the scheduler that we are calling an operation from the
  main thread that may take an extended amount of time. This can
  be used to prevent watchdog reset during expected long delays
  A value of zero cancels the previous expected delay
*/
void Scheduler::expect_delay_ms(uint32_t ms)
{
    if (!in_main_thread()) {
        // only for main thread
        return;
    }
    if (ms == 0) {
        expect_delay_start = 0;
    } else {
        expect_delay_start = AP_HAL::millis();
        expect_delay_length = ms;

        // also put our priority below timer thread if we are boosted
        boost_end();
    }
}

#endif // CH_CFG_USE_DYNAMIC