#include "pios.h"

#ifdef PIOS_INCLUDE_TIM

#include "pios_tim_priv.h"

enum pios_tim_dev_magic {
    PIOS_TIM_DEV_MAGIC = 0x87654098,
};

struct pios_tim_dev {
    enum pios_tim_dev_magic magic;

    const struct pios_tim_channel   *channels;
    uint8_t num_channels;

    const struct pios_tim_callbacks *callbacks;
    uint32_t context;
};

#if 0
static bool PIOS_TIM_validate(struct pios_tim_dev *tim_dev)
{
    return tim_dev->magic == PIOS_TIM_DEV_MAGIC;
}
#endif

#if defined(PIOS_INCLUDE_FREERTOS) && 0
static struct pios_tim_dev *PIOS_TIM_alloc(void)
{
    struct pios_tim_dev *tim_dev;

    tim_dev = (struct pios_tim_dev *)malloc(sizeof(*tim_dev));
    if (!tim_dev) {
        return NULL;
    }

    tim_dev->magic = PIOS_TIM_DEV_MAGIC;
    return tim_dev;
}
#else
static struct pios_tim_dev pios_tim_devs[PIOS_TIM_MAX_DEVS];
static uint8_t pios_tim_num_devs;
static struct pios_tim_dev *PIOS_TIM_alloc(void)
{
    struct pios_tim_dev *tim_dev;

    if (pios_tim_num_devs >= PIOS_TIM_MAX_DEVS) {
        return NULL;
    }

    tim_dev = &pios_tim_devs[pios_tim_num_devs++];
    tim_dev->magic = PIOS_TIM_DEV_MAGIC;

    return tim_dev;
}
#endif /* if defined(PIOS_INCLUDE_FREERTOS) && 0 */


int32_t PIOS_TIM_InitClock(const struct pios_tim_clock_cfg *cfg)
{
    PIOS_DEBUG_Assert(cfg);

    /* Configure the dividers for this timer */
    TIM_TimeBaseInit(cfg->timer, cfg->time_base_init);

    /* Configure internal timer clocks */
    TIM_InternalClockConfig(cfg->timer);

    /* Enable timers */
    TIM_Cmd(cfg->timer, ENABLE);

    /* Enable Interrupts */
    NVIC_Init(&cfg->irq.init);

    return 0;
}

int32_t PIOS_TIM_InitChannels(uint32_t *tim_id, const struct pios_tim_channel *channels, uint8_t num_channels, const struct pios_tim_callbacks *callbacks, uint32_t context)
{
    PIOS_Assert(channels);
    PIOS_Assert(num_channels);

    struct pios_tim_dev *tim_dev;
    tim_dev = (struct pios_tim_dev *)PIOS_TIM_alloc();
    if (!tim_dev) {
        goto out_fail;
    }

    /* Bind the configuration to the device instance */
    tim_dev->channels     = channels;
    tim_dev->num_channels = num_channels;
    tim_dev->callbacks    = callbacks;
    tim_dev->context = context;

    /* Configure the pins */
    for (uint8_t i = 0; i < num_channels; i++) {
        const struct pios_tim_channel *chan = &(channels[i]);

        GPIO_Init(chan->pin.gpio, &chan->pin.init);

        if (chan->remap) {
            GPIO_PinRemapConfig(chan->remap, ENABLE);
        }
    }

    *tim_id = (uint32_t)tim_dev;

    return 0;

out_fail:
    return -1;
}

static void PIOS_TIM_generic_irq_handler(TIM_TypeDef *timer)
{
    /* Iterate over all registered clients of the TIM layer to find channels on this timer */
    for (uint8_t i = 0; i < pios_tim_num_devs; i++) {
        const struct pios_tim_dev *tim_dev = &pios_tim_devs[i];

        if (!tim_dev->channels || tim_dev->num_channels == 0) {
            /* No channels to process on this client */
            continue;
        }

        /* Check for an overflow event on this timer */
        bool overflow_event;
        uint16_t overflow_count;
        if (TIM_GetITStatus(timer, TIM_IT_Update) == SET) {
            TIM_ClearITPendingBit(timer, TIM_IT_Update);
            overflow_count = timer->ARR;
            overflow_event = true;
        } else {
            overflow_count = 0;
            overflow_event = false;
        }

        for (uint8_t j = 0; j < tim_dev->num_channels; j++) {
            const struct pios_tim_channel *chan = &tim_dev->channels[j];

            if (chan->timer != timer) {
                /* channel is not on this timer */
                continue;
            }

            /* Figure out which interrupt bit we should be looking at */
            uint16_t timer_it;
            switch (chan->timer_chan) {
            case TIM_Channel_1:
                timer_it = TIM_IT_CC1;
                break;
            case TIM_Channel_2:
                timer_it = TIM_IT_CC2;
                break;
            case TIM_Channel_3:
                timer_it = TIM_IT_CC3;
                break;
            case TIM_Channel_4:
                timer_it = TIM_IT_CC4;
                break;
            default:
                PIOS_Assert(0);
                break;
            }

            bool edge_event;
            uint16_t edge_count;
            if (TIM_GetITStatus(chan->timer, timer_it) == SET) {
                TIM_ClearITPendingBit(chan->timer, timer_it);

                /* Read the current counter */
                switch (chan->timer_chan) {
                case TIM_Channel_1:
                    edge_count = TIM_GetCapture1(chan->timer);
                    break;
                case TIM_Channel_2:
                    edge_count = TIM_GetCapture2(chan->timer);
                    break;
                case TIM_Channel_3:
                    edge_count = TIM_GetCapture3(chan->timer);
                    break;
                case TIM_Channel_4:
                    edge_count = TIM_GetCapture4(chan->timer);
                    break;
                default:
                    PIOS_Assert(0);
                    break;
                }
                edge_event = true;
            } else {
                edge_event = false;
                edge_count = 0;
            }

            if (!tim_dev->callbacks) {
                /* No callbacks registered, we're done with this channel */
                continue;
            }

            /* Generate the appropriate callbacks */
            if (overflow_event & edge_event) {
                /*
                 * When both edge and overflow happen in the same interrupt, we
                 * need a heuristic to determine the order of the edge and overflow
                 * events so that the callbacks happen in the right order.  If we
                 * get the order wrong, our pulse width calculations could be off by up
                 * to ARR ticks.  That could be bad.
                 *
                 * Heuristic: If the edge_count is < 16 ticks above zero then we assume the
                 *            edge happened just after the overflow.
                 */

                if (edge_count < 16) {
                    /* Call the overflow callback first */
                    if (tim_dev->callbacks->overflow) {
                        (*tim_dev->callbacks->overflow)((uint32_t)tim_dev,
                                                        tim_dev->context,
                                                        j,
                                                        overflow_count);
                    }
                    /* Call the edge callback second */
                    if (tim_dev->callbacks->edge) {
                        (*tim_dev->callbacks->edge)((uint32_t)tim_dev,
                                                    tim_dev->context,
                                                    j,
                                                    edge_count);
                    }
                } else {
                    /* Call the edge callback first */
                    if (tim_dev->callbacks->edge) {
                        (*tim_dev->callbacks->edge)((uint32_t)tim_dev,
                                                    tim_dev->context,
                                                    j,
                                                    edge_count);
                    }
                    /* Call the overflow callback second */
                    if (tim_dev->callbacks->overflow) {
                        (*tim_dev->callbacks->overflow)((uint32_t)tim_dev,
                                                        tim_dev->context,
                                                        j,
                                                        overflow_count);
                    }
                }
            } else if (overflow_event && tim_dev->callbacks->overflow) {
                (*tim_dev->callbacks->overflow)((uint32_t)tim_dev,
                                                tim_dev->context,
                                                j,
                                                overflow_count);
            } else if (edge_event && tim_dev->callbacks->edge) {
                (*tim_dev->callbacks->edge)((uint32_t)tim_dev,
                                            tim_dev->context,
                                            j,
                                            edge_count);
            }
        }
    }
}
#if 0
uint16_t val = 0;
for (uint8_t i = 0; i < pios_pwm_cfg.num_channels; i++) {
    struct pios_pwm_channel channel = pios_pwm_cfg.channels[i];
    if ((channel.timer == timer) && (TIM_GetITStatus(channel.timer, channel.ccr) == SET)) {
        TIM_ClearITPendingBit(channel.timer, channel.ccr);

        switch (channel.channel) {
        case TIM_Channel_1:
            val = TIM_GetCapture1(channel.timer);
            break;
        case TIM_Channel_2:
            val = TIM_GetCapture2(channel.timer);
            break;
        case TIM_Channel_3:
            val = TIM_GetCapture3(channel.timer);
            break;
        case TIM_Channel_4:
            val = TIM_GetCapture4(channel.timer);
            break;
        }

        if (CaptureState[i] == 0) {
            RiseValue[i] = val;
        } else {
            FallValue[i] = val;
        }

        // flip state machine and capture value here
        /* Simple rise or fall state machine */
        TIM_ICInitTypeDef TIM_ICInitStructure = pios_pwm_cfg.tim_ic_init;
        if (CaptureState[i] == 0) {
            /* Switch states */
            CaptureState[i] = 1;

            /* Switch polarity of input capture */
            TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Falling;
            TIM_ICInitStructure.TIM_Channel    = channel.channel;
            TIM_ICInit(channel.timer, &TIM_ICInitStructure);
        } else {
            /* Capture computation */
            if (FallValue[i] > RiseValue[i]) {
                CaptureValue[i] = (FallValue[i] - RiseValue[i]);
            } else {
                CaptureValue[i] = ((channel.timer->ARR - RiseValue[i]) + FallValue[i]);
            }

            /* Switch states */
            CaptureState[i] = 0;

            /* Increase supervisor counter */
            CapCounter[i]++;

            /* Switch polarity of input capture */
            TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
            TIM_ICInitStructure.TIM_Channel    = channel.channel;
            TIM_ICInit(channel.timer, &TIM_ICInitStructure);
        }
    }
}
#endif /* if 0 */

/* Bind Interrupt Handlers
 *
 * Map all valid TIM IRQs to the common interrupt handler
 * and give it enough context to properly demux the various timers
 */
void TIM1_UP_IRQHandler(void) __attribute__((alias("PIOS_TIM_1_UP_irq_handler")));
static void PIOS_TIM_1_UP_irq_handler(void)
{
    PIOS_TIM_generic_irq_handler(TIM1);
}

void TIM1_CC_IRQHandler(void) __attribute__((alias("PIOS_TIM_1_CC_irq_handler")));
static void PIOS_TIM_1_CC_irq_handler(void)
{
    PIOS_TIM_generic_irq_handler(TIM1);
}

void TIM2_IRQHandler(void) __attribute__((alias("PIOS_TIM_2_irq_handler")));
static void PIOS_TIM_2_irq_handler(void)
{
    PIOS_TIM_generic_irq_handler(TIM2);
}

void TIM3_IRQHandler(void) __attribute__((alias("PIOS_TIM_3_irq_handler")));
static void PIOS_TIM_3_irq_handler(void)
{
    PIOS_TIM_generic_irq_handler(TIM3);
}

void TIM4_IRQHandler(void) __attribute__((alias("PIOS_TIM_4_irq_handler")));
static void PIOS_TIM_4_irq_handler(void)
{
    PIOS_TIM_generic_irq_handler(TIM4);
}

void TIM5_IRQHandler(void) __attribute__((alias("PIOS_TIM_5_irq_handler")));
static void PIOS_TIM_5_irq_handler(void)
{
    PIOS_TIM_generic_irq_handler(TIM5);
}

void TIM6_IRQHandler(void) __attribute__((alias("PIOS_TIM_6_irq_handler")));
static void PIOS_TIM_6_irq_handler(void)
{
    PIOS_TIM_generic_irq_handler(TIM6);
}

void TIM7_IRQHandler(void) __attribute__((alias("PIOS_TIM_7_irq_handler")));
static void PIOS_TIM_7_irq_handler(void)
{
    PIOS_TIM_generic_irq_handler(TIM7);
}

void TIM8_UP_IRQHandler(void) __attribute__((alias("PIOS_TIM_8_UP_irq_handler")));
static void PIOS_TIM_8_UP_irq_handler(void)
{
    PIOS_TIM_generic_irq_handler(TIM8);
}

void TIM8_CC_IRQHandler(void) __attribute__((alias("PIOS_TIM_8_CC_irq_handler")));
static void PIOS_TIM_8_CC_irq_handler(void)
{
    PIOS_TIM_generic_irq_handler(TIM8);
}

#endif /* PIOS_INCLUDE_TIM */