/*
 * The GAT Stand
 * GAT Host Firmware
 * by true
 *
 * version 0.0.1
 *
 * notes:
 *
 * - last 2K of flash memory is reserved for configuration storage
 */

#include <ch32v20x.h>

#include "src/btn.h"
#include "src/gat_gpio.h"
#include "src/port_pwr.h"
#include "src/rgbled.h"
#include "src/rtc.h"



void btn_top_push_cb(uint8_t idx)
{
    gat_toggle();
}

void btn_bot_push_cb(uint8_t idx)
{
    usb2_toggle();
}

static inline void systick_init(void)
{
    SysTick->CMP = (SystemCoreClock / 256 / 8) - 1; // we want a 256Hz interrupt
    SysTick->CNT = 0;                               // clear counter
    SysTick->CTLR = 0xB;                            // start counter in /8 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_Out_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_Pin = GAT_EN_PIN;
    GPIO_Init(GAT_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 will be configured later

    // USB PA11, PA12 will be configured later

    // USB2 power enable (PB4)
    gpio.GPIO_Mode = GPIO_Mode_Out_PP;
    gpio.GPIO_Pin = USB2_EN_PIN;
    GPIO_Init(USB2_EN_PORT, &gpio);

    // 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, ENABLE);
    RCC_APB2PeriphClockCmd( RCC_APB2Periph_AFIO  | RCC_APB2Periph_GPIOA |
                            RCC_APB2Periph_GPIOB | RCC_APB2Periph_GPIOD |
                            RCC_APB2Periph_ADC1, 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();

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

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


uint8_t st_tick;
volatile uint32_t uptime;

void SysTick_Handler(void)
{
    st_tick++;
    if (!st_tick) uptime++;

    btn_poll();

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