//
// Grove-LCD to wokwi-lcd1602 converter.
//
#include <stdio.h>
#include <stdlib.h>
#include "wokwi-api.h"


#define I2C_DATA_LEN            32


#define LCD_I2C_ADDR            0x3E

#define LCD_MODE_COMMAND        0x00
#define LCD_MODE_DATA           0x40

#define LCD_CLEARDISPLAY        0x01
#define LCD_RETURNHOME          0x02
#define LCD_ENTRYMODESET        0x04
#define LCD_DISPLAYCONTROL      0x08
#define LCD_CURSORSHIFT         0x10
#define LCD_FUNCTIONSET         0x20
#define LCD_SETCGRAMADDR        0x40
#define LCD_SETDDRAMADDR        0x80

#define LCD_8BITMODE            0x10
#define LCD_4BITMODE            0x00
#define LCD_2LINE               0x08
#define LCD_1LINE               0x00
#define LCD_5x10DOTS            0x04
#define LCD_5x8DOTS             0x00

#define LCD_DISPLAYON           0x04
#define LCD_DISPLAYOFF          0x00
#define LCD_CURSORON            0x02
#define LCD_CURSOROFF           0x00
#define LCD_BLINKON             0x01
#define LCD_BLINKOFF            0x00

#define LCD_ENTRYRIGHT          0x00
#define LCD_ENTRYLEFT           0x02
#define LCD_ENTRYSHIFTINC       0x01
#define LCD_ENTRYSHIFTDEC       0x00


typedef struct {
  int idx;
  uint8_t data[I2C_DATA_LEN];
} i2c_t;

typedef struct {
  pin_t pin_rs;
  pin_t pin_rw;
  pin_t pin_e;
  pin_t pin_d0;
  pin_t pin_d1;
  pin_t pin_d2;
  pin_t pin_d3;
  pin_t pin_d4;
  pin_t pin_d5;
  pin_t pin_d6;
  pin_t pin_d7;
  pin_t pin_a;
  pin_t pin_k;
  i2c_t i2c;
} chip_state_t;


void lcd_write(chip_state_t *chip)
{
  if ((chip->i2c.data[0] & LCD_MODE_DATA) == 0) {
    if ((chip->i2c.data[1] & 0x70) == LCD_FUNCTIONSET) {
      chip->i2c.data[1] |= LCD_8BITMODE;
    }
    pin_write(chip->pin_rs, LOW);
  } else {
    pin_write(chip->pin_rs, HIGH);
  }

  for (int i = 1; i < chip->i2c.idx; i++) {
    pin_write(chip->pin_d0, (chip->i2c.data[i] & (1 << 0)) ? HIGH : LOW);
    pin_write(chip->pin_d1, (chip->i2c.data[i] & (1 << 1)) ? HIGH : LOW);
    pin_write(chip->pin_d2, (chip->i2c.data[i] & (1 << 2)) ? HIGH : LOW);
    pin_write(chip->pin_d3, (chip->i2c.data[i] & (1 << 3)) ? HIGH : LOW);
    pin_write(chip->pin_d4, (chip->i2c.data[i] & (1 << 4)) ? HIGH : LOW);
    pin_write(chip->pin_d5, (chip->i2c.data[i] & (1 << 5)) ? HIGH : LOW);
    pin_write(chip->pin_d6, (chip->i2c.data[i] & (1 << 6)) ? HIGH : LOW);
    pin_write(chip->pin_d7, (chip->i2c.data[i] & (1 << 7)) ? HIGH : LOW);
    pin_write(chip->pin_e, HIGH);
    pin_write(chip->pin_e, LOW);
    pin_write(chip->pin_rs, HIGH);
  }
}

void lcd_init(chip_state_t *chip)
{
  chip->i2c.idx = 2;
  chip->i2c.data[0] = LCD_MODE_COMMAND;
  chip->i2c.data[1] = (LCD_FUNCTIONSET | LCD_8BITMODE) >> 4;
  for (int i = 0; i < 3; i++) {
    lcd_write(chip);
  }
}

bool on_i2c_connect(void *user_data, uint32_t address, bool read)
{
  chip_state_t *chip = user_data;

  chip->i2c.idx = 0;

  return true;
}

uint8_t on_i2c_read(void *user_data)
{
  return 0;
}

bool on_i2c_write(void *user_data, uint8_t data)
{
  chip_state_t *chip = user_data;

  chip->i2c.data[chip->i2c.idx] = data;
  if (chip->i2c.idx < (I2C_DATA_LEN - 1)) {
    chip->i2c.idx++;
  }

  return true;
}

void on_i2c_disconnect(void *user_data)
{
  chip_state_t *chip = user_data;

  if (chip->i2c.idx > 1) {
    lcd_write(chip);
  }
}

void chip_init()
{
  chip_state_t *chip = calloc(1, sizeof(chip_state_t));

  chip->pin_rs = pin_init("RS", OUTPUT_LOW);
  chip->pin_rw = pin_init("RW", OUTPUT_LOW);
  chip->pin_e = pin_init("E", OUTPUT_LOW);
  chip->pin_d0 = pin_init("D0", OUTPUT_LOW);
  chip->pin_d1 = pin_init("D1", OUTPUT_LOW);
  chip->pin_d2 = pin_init("D2", OUTPUT_LOW);
  chip->pin_d3 = pin_init("D3", OUTPUT_LOW);
  chip->pin_d4 = pin_init("D4", OUTPUT_LOW);
  chip->pin_d5 = pin_init("D5", OUTPUT_LOW);
  chip->pin_d6 = pin_init("D6", OUTPUT_LOW);
  chip->pin_d7 = pin_init("D7", OUTPUT_LOW);
  chip->pin_a = pin_init("A", OUTPUT_HIGH);
  chip->pin_k = pin_init("K", OUTPUT_LOW);

  const i2c_config_t i2c_config = {
    .address = LCD_I2C_ADDR,
    .scl = pin_init("SCL", INPUT_PULLUP),
    .sda = pin_init("SDA", INPUT_PULLUP),
    .connect = on_i2c_connect,
    .read = on_i2c_read,
    .write = on_i2c_write,
    .disconnect = on_i2c_disconnect,
    .user_data = chip
  };
  i2c_init(&i2c_config);

  lcd_init(chip);
}