/*
 * The GAT Stand
 * GAT Host Firmware
 * by true
 *
 * version 0.0.1
 *
 *
 * notes:
 *
 * - last 2K of flash memory is reserved for configuration storage
 *
 *
 * project todo:
 *
 * - implement config storage
 *
 * - implement USB CDC commmand shell
 *
 * - when USB is not active, go into super low power state
 *   - light sensor is only checked once every two seconds or so
 *   - buttons are on wakeup
 */

#include <ch32v20x.h>

#include "periph/adc.h"
#include "periph/btn.h"
#include "periph/gat_gpio.h"
#include "periph/port_pwr.h"
#include "periph/rgbled.h"
#include "periph/rtc.h"

#include "periph/usb/cdc.h"
#include "usb_lib.h"



void btn_top_push_cb(uint8_t idx)
{
    // jumper 3, if set, will manage power by brightness automatically
    // only respect the button if this switch isn't set
    if (!(btn[DIP3]._mask & BTN_PUSH)) {
        gat_toggle();
    }
}

void btn_bot_push_cb(uint8_t idx)
{
    // jumper 3, if set, will manage power by brightness automatically
    // only respect the button if this switch isn't set
    if (!(btn[DIP3]._mask & BTN_PUSH)) {
        usb2_toggle();
    }
}

static inline void systick_init(void)
{
    SysTick->CMP = (SystemCoreClock / 256) - 1;     // we want a 256Hz interrupt
    SysTick->CNT = 0;                               // clear counter
    SysTick->CTLR = 0xF;                            // start counter in /1 mode, enable interrupts, auto-reset counter
    SysTick->SR = 0;                                // clear count comparison flag

    NVIC_EnableIRQ(SysTicK_IRQn);                   // enable interrupt
}

static void gpio_init()
{
    GPIO_InitTypeDef gpio = {0};

    gpio.GPIO_Speed = GPIO_Speed_2MHz;

    // unused pins
    gpio.GPIO_Mode = GPIO_Mode_IPD;
    gpio.GPIO_Pin = GPIO_Pin_13;
    GPIO_Init(GPIOC, &gpio);

    gpio.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1;
    GPIO_Init(GPIOD, &gpio);

    gpio.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7 | GPIO_Pin_8;
    GPIO_Init(GPIOA, &gpio);

    gpio.GPIO_Pin = GPIO_Pin_1 | GPIO_Pin_2 | GPIO_Pin_5 | GPIO_Pin_15;
    GPIO_Init(GPIOB, &gpio);

    // OSC32K: don't need to configure these pins from defaults
    // enabling RTC does whatever is needed for these pins (assumed from example)

    // RGBLED (PA0, PA1, PA2)
    RGBLED_PORT->BSHR = RGBLED_PIN_R | RGBLED_PIN_G | RGBLED_PIN_B;
    gpio.GPIO_Mode = GPIO_Mode_AF_PP;
    gpio.GPIO_Pin = RGBLED_PIN_R | RGBLED_PIN_G | RGBLED_PIN_B;
    GPIO_Init(RGBLED_PORT, &gpio);

    // GAT power enable (PA3)
    GAT_EN_PORT->BCR = GAT_EN_PIN;
    gpio.GPIO_Mode = GPIO_Mode_Out_PP;
    gpio.GPIO_Pin = GAT_EN_PIN;
    GPIO_Init(GAT_EN_PORT, &gpio);

    // lightsense anode (PA5)
    LSENS_A_PORT->BCR = LSENS_A_PIN;
    gpio.GPIO_Pin = LSENS_A_PIN;
    GPIO_Init(LSENS_A_PORT, &gpio);

    // lightsense cathode (PB0)
    LSENS_K_PORT->BCR = LSENS_K_PIN;
    gpio.GPIO_Pin = LSENS_K_PIN;
    GPIO_Init(LSENS_K_PORT, &gpio);

    // USB2 power enable (PB4)
    USB2_EN_PORT->BCR = USB2_EN_PIN;
    gpio.GPIO_Pin = USB2_EN_PIN;
    GPIO_Init(USB2_EN_PORT, &gpio);

    // GAT overcurrent detect (PA4)
    gpio.GPIO_Mode = GPIO_Mode_IPU;
    gpio.GPIO_Pin = GAT_OC_PIN;
    GPIO_Init(GAT_EN_PORT, &gpio);


    // buttons (PB10, PB11) and DIP switches (PB12, PB13, PB14)
    gpio.GPIO_Pin = GPIO_Pin_10 | GPIO_Pin_11 | GPIO_Pin_12 | GPIO_Pin_13 | GPIO_Pin_14;
    GPIO_Init(GPIOB, &gpio);

    // GAT GPIO is configured in gat_gpio.c

    // USB PA11, PA12 will be configured later

    // unused pins that are used for I2C passthrough
    gpio.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    gpio.GPIO_Pin = GPIO_Pin_15;
    GPIO_Init(GPIOA, &gpio);
    gpio.GPIO_Pin = GPIO_Pin_3;
    GPIO_Init(GPIOB, &gpio);

    // USB PB6, PB7 will be configured later

    // I2C (PB8, PB9) - remapped
    GPIO_PinRemapConfig(GPIO_Remap_I2C1, ENABLE);
    gpio.GPIO_Speed = GPIO_Speed_10MHz;
    gpio.GPIO_Mode = GPIO_Mode_AF_OD;
    gpio.GPIO_Mode = GPIO_Pin_8 | GPIO_Pin_9;
    GPIO_Init(GPIOB, &gpio);
}

int main(void)
{
    // configure core
    NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);
    SystemCoreClockUpdate();

    // enable peripheral clocks
    RCC_APB1PeriphClockCmd( RCC_APB1Periph_PWR   | RCC_APB1Periph_BKP |
                            RCC_APB1Periph_I2C1  | RCC_APB1Periph_TIM2, ENABLE);
    RCC_APB2PeriphClockCmd( RCC_APB2Periph_AFIO  | RCC_APB2Periph_GPIOA |
                            RCC_APB2Periph_GPIOB | RCC_APB2Periph_GPIOD |
                            RCC_APB2Periph_ADC1, ENABLE);
    RCC_AHBPeriphClockCmd(  RCC_AHBPeriph_USBHS, ENABLE);


    // configure gpio pins
    gpio_init();

    // configure RTC
    if (rtc_init()) {
        // rtc failed to initialize. let the end user know.
        // todo
    }

    // initialize buttons
    btn_init();
    btn[0].cb_push = btn_top_push_cb;
    btn[1].cb_push = btn_bot_push_cb;

    // set GAT GP pins weak pull to address the addon
    gat_gpio_init();

    // set output ports to saved state, or on if no batt / first boot
    port_pwr_init();

    // start up rgbled
    rgbled_init();

    // initialize light sense stuff
    adc_init();

    // get the system tick interrupt going
    systick_init();

    // initialize USB device for console shell
    usb_conf_clksource();
    USB_Init();
    usb_intr_init();

    // let's do this
    while (1) {
        __WFI();
    }
}


uint8_t st_tick;
volatile uint32_t uptime;

__attribute__((interrupt("WCH-Interrupt-fast")))
void SysTick_Handler(void)
{
    st_tick++;
    if (!st_tick) {
        uptime++;

        // jumper 3, if set, will manage power by brightness automatically
        if (btn[DIP3]._mask & BTN_PUSH) {
            if (adc_get_lsens_coarse() > LSENS_DARK) {
                gat_off();
                usb2_off();
            }
            if (adc_get_lsens_coarse() <= LSENS_BRIGHT) {
                gat_on();
                usb2_on();
            }
        }
    }

    // light sensor updating at ~4ms
    adc_process_lsens();

    // update buttons
    btn_poll();

    if (!(st_tick & 0x3)) {
        rgbled_update();
    }

    // clear comparison flag
    SysTick->SR = 0;

    if (SysTick->SR) {
        while (1);
    }
}