#include "stm32f401xe.h"
#include "timer.h"
#include <stdint.h>
#include <stdbool.h>
#include <stm32f4xx.h>
#include "exti.h"
#include "pin.h"
#include "registers.h"
#include "display.h"
#include "delay.h"
#include "uart.h"
#include "spi.h"
#include "buffered_peripheral.h"
#include "spi_matrix.h"

void hard_fault_handler() {
  while(1) {}
}

void usage_fault_handler() {
  while(1) {}
}

void nmi_handler() {
  while(1) {}
}

void bus_fault_handler() {
  while(1) {}
}


/*----------------------------------------------------------------------------
 * SystemCoreClockConfigure: configure SystemCoreClock using HSI
                             (HSE is not populated on Nucleo board)
 *----------------------------------------------------------------------------*/
void SystemCoreClockSetHSI(void) {

  RCC->CR |= ((uint32_t)RCC_CR_HSION);                     // Enable HSI
  while ((RCC->CR & RCC_CR_HSIRDY) == 0);                  // Wait for HSI Ready

  RCC->CFGR = RCC_CFGR_SW_HSI;                             // HSI is system clock
  while ((RCC->CFGR & RCC_CFGR_SWS) != RCC_CFGR_SWS_HSI);  // Wait for HSI used as system clock

  FLASH->ACR  = FLASH_ACR_PRFTEN;                          // Enable Prefetch Buffer
  FLASH->ACR |= FLASH_ACR_ICEN;                            // Instruction cache enable
  FLASH->ACR |= FLASH_ACR_DCEN;                            // Data cache enable
  FLASH->ACR |= FLASH_ACR_LATENCY_5WS;                     // Flash 5 wait state

  RCC->CFGR |= RCC_CFGR_HPRE_DIV1;                         // HCLK = SYSCLK
  RCC->CFGR |= RCC_CFGR_PPRE1_DIV4;                        // APB1 = HCLK/4
  RCC->CFGR |= RCC_CFGR_PPRE2_DIV2;                        // APB2 = HCLK/2

  RCC->CR &= ~RCC_CR_PLLON;                                // Disable PLL

  // HSI = 16 MHz
  // PLL configuration:  VCO = HSI/M * N,  Sysclk = VCO/P
  // => Sysclk = 48 MHz, APB1 = 12 MHz, APB2 = 24 MHz
  // Since divider for APB1 is != 1, timer clock is 24 MHz
  RCC->PLLCFGR = ( 16ul                   |                // PLL_M =  16
                 (384ul <<  6)            |                // PLL_N = 384
                 (  3ul << 16)            |                // PLL_P =   8
                 (RCC_PLLCFGR_PLLSRC_HSI) |                // PLL_SRC = HSI
                 (  8ul << 24)             );              // PLL_Q =   8

  RCC->CR |= RCC_CR_PLLON;                                 // Enable PLL
  while((RCC->CR & RCC_CR_PLLRDY) == 0) __NOP();           // Wait till PLL is ready

  RCC->CFGR &= ~RCC_CFGR_SW;                               // Select PLL as system clock source
  RCC->CFGR |=  RCC_CFGR_SW_PLL;
  while ((RCC->CFGR & RCC_CFGR_SWS) != RCC_CFGR_SWS_PLL);  // Wait till PLL is system clock src
}

#define COMMAND_SEPARATOR '\n'

// Button
pin_t user_button;
timer_t button_timer;
exti_t button_exti;
pin_t led;

// Display
matrix_t matrix;
timer_t matrix_timer;

// SPI
pin_t spi_csn;
spi_t matrix_spi;
buffered_transceiver_t matrix_tx;
timer_t spi_csn_timer;

// Uart
uart_t uart;
buffered_transceiver_t uart_rx;

#define MAX_CMD_LENGTH 65

#define AUTO_TOGGLE_CYCLES 1000000
#define MAX_IMAGES 10

#define COLS 8
#define ROWS 8

uint8_t images_count = 4;
uint8_t current_image = 0;
uint8_t images[MAX_IMAGES][8] = {
    {0b11111111, 0b10000001, 0b10000001, 0b10000001, 0b10000001, 0b10000001, 0b10000001, 0b11111111},
    { 0b00000100, 0b00001110, 0b11110001, 0b10000101, 0b10000001, 0b10110001, 0b10110001, 0b11111111 },
    { 0b11111000, 0b11100100, 0b11100010, 0b10000001, 0b10000001, 0b01000010, 0b00100100, 0b00011000 },
    { 0b11000000, 0b10011000, 0b11010000, 0b10011010, 0b10010010, 0b00011010, 0b00000010, 0b00000011 },
};

uint32_t cycle = 0;
bool auto_toggle = false;
bool toggle_next = false;

bool animation = false;

void num_to_string(uint16_t num, char* res, uint16_t digits) {
  for (uint16_t i = 0; i < digits; i++) {
    res[digits - 1 - i] = num % 10 + '0';
    num /= 10;
  }
}

void handle_command(char* cmd, uint16_t len) {
  if (len == 0) {
    return;
  }

  bool handled = false;

  switch (cmd[0]) {
  case 'n': // next
    if (len == 1) {
      handled = true;
      toggle_next = true;
      buffered_transceiver_transmit(&uart_rx, "Switching to next image.\r\n", 0);
    }
    break;
  case 'N': // auto toggle
    if (len == 1) {
      handled = true;
      auto_toggle = !auto_toggle;

      if (auto_toggle) {
        buffered_transceiver_transmit(&uart_rx, "Going to toggle automatically.\r\n", 0);
      } else {
        buffered_transceiver_transmit(&uart_rx, "Manual switch mode.\r\n", 0);
      }
    }
    break;
  case 'a': // animate
    if (len == 1) {
      handled = true;
      animation = !animation;

      if (animation) {
        buffered_transceiver_transmit(&uart_rx, "Animation enabled.\r\n", 0);
      } else {
        buffered_transceiver_transmit(&uart_rx, "Animation disabled.\r\n", 0);
      }
    }
    break;
  case 'u': // upload
    // upload
    // TODO
    break;
  case 's': // number of slots is...
    if (len == 1) {
      handled = true;

      buffered_transceiver_transmit(&uart_rx, "Used slots: ", 0);

      char str[5] = { '\0', '\0', '\r', '\n', '\0' };
      num_to_string(images_count, str, 2);
      buffered_transceiver_transmit(&uart_rx, str, 0);
    }
    break;
  case 'I': // increase intensity
    if (len == 1) {
      matrix_increase_intensity(&matrix);
      buffered_transceiver_transmit(&uart_rx, "Increasing intensity.\r\n", 0);
      handled = true;
    }
    break;
  case 'i': // decrease intensity
    if (len == 1) {
      matrix_decrease_intensity(&matrix);
      buffered_transceiver_transmit(&uart_rx, "Decreasing intensity.\r\n", 0);
      handled = true;
    }
    break;
  case 'h':
    buffered_transceiver_transmit(&uart_rx, "Help:\r\n", 0);
    buffered_transceiver_transmit(&uart_rx, " h - show this help messages\r\n", 0);
    buffered_transceiver_transmit(&uart_rx, " s - print used slots\r\n", 0);
    buffered_transceiver_transmit(&uart_rx, " a - toggle animating\r\n", 0);
    buffered_transceiver_transmit(&uart_rx, " n - next image\r\n", 0);
    buffered_transceiver_transmit(&uart_rx, " N - automatically switch images\r\n", 0);
    buffered_transceiver_transmit(&uart_rx, " I - increase intensity\r\n", 0);
    buffered_transceiver_transmit(&uart_rx, " i - decrease intensity\r\n", 0);
    buffered_transceiver_transmit(&uart_rx, " uIMG - upload new image, IMG has \"X\" for 1s and \"-\" for 0s. It should be 64 chars long\r\n", 0);
    handled = true;
    break;
  default:
    break;
  }

  if (!handled) {
    buffered_transceiver_transmit(&uart_rx, "Unknown command!\r\n", 0);
  }
}

char* receive_command(uint16_t* length)
{
  static char cmd[MAX_CMD_LENGTH];
  static uint16_t index;

  char* current_char = (cmd + index);

  while (buffered_transceiver_receive(&uart_rx, current_char, 1) == 1) {
    // echo
    buffered_transceiver_transmit(&uart_rx, current_char, 1);

    if (*current_char == COMMAND_SEPARATOR) {
      buffered_transceiver_transmit(&uart_rx, "\r", 1);
      *current_char = '\0';
      *length = index;
      index = 0;
      return cmd;
    }

    index++;
  }

  // Commands are separated either through max length, or by new line
  if (index == MAX_CMD_LENGTH + 1) {
    *length = MAX_CMD_LENGTH;
    index = 0;
    return cmd;
  }

  return NULL;
}

void next_image()
{
  if (matrix.state != MATRIX_STABLE) {
    return;
  }

  current_image++;
  current_image %= images_count;

  matrix_set_buffer(&matrix, MATRIX_SLOT_OTHER, &images[current_image][0]);

  if (animation) {
    matrix_animate_swap(&matrix);
  } else {
    matrix_swap(&matrix);
  }
}

void app_loop()
{
  while (1) {

    if (auto_toggle) {
      pin_set(&led);
    } else {
      pin_reset(&led);
    }

    if (auto_toggle && cycle >= AUTO_TOGGLE_CYCLES) {
      next_image();
      cycle = 0;
    } else if (toggle_next) {
      next_image();
      toggle_next = false;
    }

    uint16_t command_len;
    char* cmd = receive_command(&command_len);
    if (cmd != NULL) {
      handle_command(cmd, command_len);
    }

    cycle++;
  }
}

void main()
{
  // Setup
  SystemCoreClockSetHSI();
  systick_configure();

  RCC->AHB1ENR |= RCC_AHB1ENR_GPIOAEN | RCC_AHB1ENR_GPIOBEN | RCC_AHB1ENR_GPIOCEN;
  RCC->APB1ENR |= RCC_APB1ENR_TIM3EN | RCC_APB1ENR_TIM4EN | RCC_APB1ENR_USART2EN | RCC_APB1ENR_TIM2EN;
  RCC->APB2ENR |= RCC_APB2ENR_SYSCFGEN | RCC_APB2LPENR_SPI1LPEN;

  { // UART init
    pin_t pin_rx;
    pin_t pin_tx;

    #define UART_RX_BUFFER_SIZE 64
    #define UART_TX_BUFFER_SIZE 300

    static queue_t uart_rx_queue, uart_tx_queue;
    static uint16_t uart_rx_buffer[UART_RX_BUFFER_SIZE], uart_tx_buffer[UART_TX_BUFFER_SIZE];

    queue_init(&uart_rx_queue, sizeof(char), UART_RX_BUFFER_SIZE, uart_rx_buffer);
    queue_init(&uart_tx_queue, sizeof(char), UART_TX_BUFFER_SIZE, uart_tx_buffer);

    bool usart_generic_can_receive(void* peripheral);
    bool usart_generic_can_transmit(void* peripheral);

    uint16_t usart_generic_receive(void* peripheral, void* buffer, uint16_t max_size);
    uint16_t usart_generic_transmit(void* peripheral, void* data, uint16_t size);

    buffered_transceiver_vtable_t vtable = {
      .can_receive = usart_generic_can_receive,
      .can_transmit = usart_generic_can_transmit,
      .transmit = usart_generic_transmit,
      .receive = usart_generic_receive,
    };

    buffered_transceiver_init(&uart_rx, &uart_rx_queue, &uart_tx_queue, &uart, vtable);

    pin_init(&pin_tx, GPIOA, 2);
    pin_init(&pin_rx, GPIOA, 3);

    pin_into_alternate(&pin_rx, 7);
    pin_into_alternate(&pin_tx, 7);

    usart_init(&uart, USART2, 2);
    usart_configure_speed(&uart, 12000000, 9600);
    usart_configure_uart(&uart, true, USART_WORD_9_BITS, true,
                         USART_PARITY_EVEN, USART_STOP_BIT_ONE);
    usart_enable_interrupt(&uart, false, true);
    usart_configure_transmitter(&uart, true);
    usart_configure_receiver(&uart, true);
  }

  { // SPI init
    pin_t pin_mosi;
    pin_t pin_csn;
    pin_t pin_clk;

    #define SPI_RX_BUFFER_SIZE 0
    #define SPI_TX_BUFFER_SIZE 10

    static queue_t spi_rx_queue, spi_tx_queue;
    static uint16_t spi_rx_buffer[SPI_RX_BUFFER_SIZE], spi_tx_buffer[SPI_TX_BUFFER_SIZE];

    queue_init(&spi_rx_queue, sizeof(uint16_t), SPI_RX_BUFFER_SIZE, spi_rx_buffer);
    queue_init(&spi_tx_queue, sizeof(uint16_t), SPI_TX_BUFFER_SIZE, spi_tx_buffer);

    bool spi_generic_can_receive(void* peripheral);
    bool spi_generic_can_transmit(void* peripheral);

    uint16_t spi_generic_receive(void* peripheral, void* buffer, uint16_t max_size);
    uint16_t spi_generic_transmit(void* peripheral, void* data, uint16_t size);

    buffered_transceiver_vtable_t vtable = {
      .can_receive = spi_generic_can_receive,
      .can_transmit = spi_generic_can_transmit,
      .transmit = spi_generic_transmit,
      .receive = spi_generic_receive,
    };

    buffered_transceiver_init(&matrix_tx, &spi_rx_queue, &spi_tx_queue, &matrix_spi, vtable);

    pin_init(&pin_mosi, GPIOA, 7);
    pin_init(&pin_csn, GPIOA, 4);
    pin_init(&pin_clk, GPIOB, 3);

    pin_into_alternate(&pin_mosi, 5);
    /* pin_into_alternate(&pin_csn, 5); */
    pin_into_alternate(&pin_clk, 5);

    pin_set(&pin_csn);
    pin_into_output_pushpull(&pin_csn);

    spi_init(&matrix_spi, pin_csn, SPI1, 1);
    spi_master_configure_speed(&matrix_spi, 7);
    spi_master_configure(&matrix_spi, false, false, false,
                         SPI_MSB_FIRST, SPI_FRAME_16_BIT);

    spi_enable_interrupt(&matrix_spi, false, true);
    spi_master_enable(&matrix_spi, true);
  }

  { // Matrix, timer init
    matrix_init(&matrix, &matrix_tx, 5);
    matrix_setup(&matrix);
    matrix_enable(&matrix, true);

    matrix_set_buffer(&matrix, MATRIX_SLOT0, images[current_image]);
    timer_init(&matrix_timer, TIM3, 3);
    timer_set_refresh(&matrix_timer, 20);
    timer_configure(&matrix_timer, 0, 60000, 0);
    timer_enable_interrupt(&matrix_timer, true, false);
    timer_enable(&matrix_timer);
  }

  { // Button, exti, timer
    pin_init(&user_button, GPIOC, 13);
    pin_into_input(&user_button);

    pin_init(&led, GPIOA, 5);
    pin_into_output(&led);

    exti_init(&button_exti, 13, EXTI, SYSCFG);
    exti_external_interrupt(&button_exti, 2);
    exti_both_edges_interrupt(&button_exti);
    exti_clear_interrupt(&button_exti);
    exti_enable_interrupt(&button_exti);

    timer_init(&button_timer, TIM2, 2);
    timer_set_refresh(&button_timer, 400);
    timer_configure(&button_timer, 0, 60000, 1);

    timer_enable_interrupt(&button_timer, true, false);
  }

  __enable_irq();

  // Application
  app_loop();
}

void EXTI15_10_handler(void) {
  if (exti_is_interrupt(&button_exti)) {
    exti_clear_interrupt(&button_exti);

    bool button_pressed = !pin_read(&user_button);
    if (button_pressed) { // start timer on button press
      timer_set_counter(&button_timer, 0);
      timer_clear_update_interrupt(&button_timer);
      timer_enable(&button_timer);

      // handle short presses, prevent registering bouncing
    } else if (timer_count(&button_timer) > 10) {
      timer_disable(&button_timer);
      timer_set_counter(&button_timer, 0);

      // short press (under 1 s)
      if (auto_toggle) {
        auto_toggle = false;
      } else {
        toggle_next = true;
      }
    }
  }
}

void TIM2_handler(void) {
  if (timer_is_update_interrupt(&button_timer)) {
    timer_clear_update_interrupt(&button_timer);

    // long press (over 1 s)
    auto_toggle = !auto_toggle;
    cycle = 0;
  }
}

void TIM3_handler(void) {
  timer_clear_update_interrupt(&matrix_timer);
  matrix_update(&matrix, &matrix_tx);
}

// A flag to prevent spi communication,
// to toggle csn high
bool spi_can_transmit_flag = true;

void SPI1_handler(void) {
  // using can receive as not busy interrupt
  if (spi_can_receive(&matrix_spi)) {
    uint16_t tmp;
    spi_receive(&matrix_spi, &tmp, 1);

    spi_pulse_csn(&matrix_spi);
    spi_can_transmit_flag = true;
    buffered_transceiver_trigger_transmit(&matrix_tx, 1);
  }
}

void USART2_handler(void) {
  if (usart_can_receive(&uart)) {
    buffered_transceiver_trigger_receive(&uart_rx, 1);
  }
  if (usart_can_transmit(&uart)) {
    if (!buffered_transceiver_trigger_transmit(&uart_rx, 1)) {
      usart_enable_interrupt(&uart, false, true);
    }
  }
}


bool spi_generic_can_receive(void *peripheral) {
  return spi_can_receive((spi_t*)peripheral);
}
bool spi_generic_can_transmit(void *peripheral) {
  return spi_can_transmit_flag && (((spi_t*)peripheral)->periph->SR & SPI_SR_BSY) == 0;
}

uint16_t spi_generic_receive(void *peripheral, void *buffer,
                             uint16_t max_size) {
  return spi_receive((spi_t*)peripheral, buffer, max_size);
}
uint16_t spi_generic_transmit(void *peripheral, void *data, uint16_t size) {
  // enable the interrupt so that we can send the rest
  uint16_t ret = spi_transmit((spi_t*)peripheral, data, size);
  spi_can_transmit_flag = false;
  return ret;
}

bool usart_generic_can_receive(void *peripheral) {
  return usart_can_receive((uart_t*)peripheral);
}
bool usart_generic_can_transmit(void *peripheral) {
  return usart_can_transmit((uart_t*)peripheral);
}

uint16_t usart_generic_receive(void *peripheral, void *buffer,
                             uint16_t max_size) {
  return usart_receive((uart_t*)peripheral, buffer, max_size);
}
uint16_t usart_generic_transmit(void *peripheral, void *data, uint16_t size) {
  uint16_t ret = usart_transmit((uart_t*)peripheral, data, size);
  // enable the interrupt so that we can send the rest
  usart_enable_interrupt((uart_t*)peripheral, true, true);
  return ret;
}