#include "arch.h"

#include "arch/stm32l4xxx/peripherals/clock.h"
#include "arch/stm32l4xxx/peripherals/dma.h"
#include "arch/stm32l4xxx/peripherals/gpio.h"
#include "arch/stm32l4xxx/peripherals/system.h"
#include "arch/stm32l4xxx/peripherals/usart.h"
#include "arch/stm32l4xxx/peripherals/nvic.h"
#include "arch/stm32l4xxx/peripherals/irq.h"

#include "kern/dma/dma_manager.h"
#include "kern/gpio/gpio_manager.h"
#include "kern/gpio/sysled.h"

#include "kern/delay.h"
#include "kern/mem.h"
#include "kern/string.h"

/** Overrides the default systick irq handler. */
void on_systick()
{
  static int is_on = 0;
  gpio_reserved_pin_t sysled = get_sysled();

  if (is_on) {
    set_gpio_pin_low(sysled);
  } else {
    set_gpio_pin_high(sysled);
  }

  is_on = ! is_on;
}

void setup_usart2(uint32_t baud_rate)
{
  enable_hsi(&RCC, true);

  int ec = 0;
  gpio_enable_alternate_function(
      GPIO_ALTERNATE_FUNCTION_USART2_TX, GPIO_PIN_PA2, &ec);

  if (ec) {
    unhandled_isr(ec & 0xff);
  }

  gpio_enable_alternate_function(
      GPIO_ALTERNATE_FUNCTION_USART2_RX, GPIO_PIN_PA15, &ec);

  if (ec) {
    unhandled_isr(ec & 0xff);
  }

  set_usart2_clock_src(&RCC, USART_CLK_SRC_HSI16);
  set_usart2_clock_enabled(&RCC, USART_CLK_SRC_HSI16);

  /* De-assert reset of USART2 */
  regset(RCC.apb1rst1_r, rcc_usart2rst, 0);

  USART2.c_r1 = 0;
  USART2.c_r2 = 0;
  USART2.c_r3 = 0;

  usart_set_divisor(&USART2, 16000000 / baud_rate);
}

#ifdef ARCH_STM32L4

/* Main function. This gets executed from the interrupt vector defined above. */
int main()
{
  /* Enable a higher clock frequency. */
  set_system_clock_MHz(80);

  setup_usart2(115200);
  regset(USART2.c_r1, usart_txeie, 1);
  regset(USART2.c_r1, usart_rxneie, 1);
  usart_enable_dma(&USART2, USART_ENABLE_TX);
  usart_set_enabled(&USART2, USART_ENABLE_TX | USART_ENABLE_RX);


  dma_opts_t opts = DEFAULT_DMA_OPTS;
  opts.transfer_complete_interrupt_enable = 1;
  int ec = 0;
  dma_mem2p_channel_t dma_chan =
    select_dma_channel_mem2p(DMA1_PERIPH_USART2_TX, &opts, &ec);
  enable_interrupt(dma_channel_get_interrupt(dma_chan.c_));

  if (ec) {
    usart_printf(&USART2, "Select DMA channel failed :( %d\n", ec);
    for (;;);
  }

  // const char* thing = "Good Thing This Works!";

  char* str = halloc(128);
  kstrcpy(str, "Hello, Heap!");

  usart_printf(&USART2, "DATA_SEGMENT_START %p\n", &DATA_SEGMENT_START);
  usart_printf(&USART2, "DATA_SEGMENT_STOP: %p\n", &DATA_SEGMENT_STOP);
  usart_printf(&USART2, "str at: %p\n", str);
  usart_printf(&USART2, "str: %s\n", str);
  // usart_printf(&USART2, "%s\n", thing);
  // regset(USART2.ic_r, usart_tccf, 1);
  // dma_mem2p_initiate_transfer(dma_chan, thing, strlen(thing));

  gpio_reserved_pin_t sysled = get_sysled();
  set_gpio_pin_high(sysled);

  // usart_printf(&USART2, "Start Configuring Countdown!\n");

  /* Set the countdown to start from 1,000,0000. */
  SCB.strv_r = 1000000;

  /* Enable interrupts. */
  regset(SCB.stcs_r, scb_tickint, 1);

  /* Start the systick. */
  regset(SCB.stcs_r, scb_enable, 1);

  // usart_printf(&USART2, "Start Countdown Started!\n");
}

#endif