#include "lcd.h"
#include "ch32v20x.h"


void lcd_begin(lcd_t *lcd);
void lcd_expander_write(lcd_t *lcd, uint8_t data);
void lcd_write4bits(lcd_t *lcd, uint8_t value);
void lcd_command(lcd_t *lcd, uint8_t cmd);


void lcd_init(lcd_t *lcd, u8 address) {
	lcd->address = address;
	lcd->backlight = 0;

    // Enable I2C1 and GPIOB
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB | RCC_APB2Periph_AFIO, ENABLE);
    GPIO_PinRemapConfig(GPIO_Remap_I2C1, ENABLE);

    // Set up GPIO on port B
    GPIO_InitTypeDef GPIO_InitStructure;
    GPIO_StructInit(&GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_OD;

    // SCL - PB8
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;
    GPIO_Init(GPIOB, &GPIO_InitStructure);

    // SDA - PB9
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
    GPIO_Init(GPIOB, &GPIO_InitStructure);

    I2C_DeInit(I2C1);

    I2C_InitTypeDef I2C_InitStructure;
    I2C_StructInit(&I2C_InitStructure);
    I2C_InitStructure.I2C_ClockSpeed = 100000;
    I2C_Init(I2C1, &I2C_InitStructure);

    I2C_Cmd(I2C1, ENABLE);

    lcd_begin(lcd);
}

void lcd_begin(lcd_t *lcd) {
	lcd->backlight = LCD_BACKLIGHT;
	Delay_Ms(50);

	lcd_expander_write(lcd, 0);
	Delay_Ms(1000);

	lcd_write4bits(lcd, 0x03 << 4);
	Delay_Us(4500);
	lcd_write4bits(lcd, 0x03 << 4);
	Delay_Us(4500);
	lcd_write4bits(lcd, 0x03 << 4);
	Delay_Us(150);
	lcd_write4bits(lcd, 0x02 << 4);

	lcd->function = LCD_4BITMODE | LCD_2LINE;
	lcd_command(lcd, LCD_FUNCTIONSET | lcd->function);

	lcd->dispctrl = LCD_DISPLAYON | LCD_CURSOROFF | LCD_BLINKOFF;
	lcd_command(lcd, LCD_DISPLAYCONTROL | lcd->dispctrl);

	lcd->entrymode = LCD_ENTRYLEFT | LCD_ENTRYSHIFTDEC;
	lcd_command(lcd, LCD_ENTRYMODESET | lcd->entrymode);

	lcd_clear(lcd);
	lcd_home(lcd);
}

void lcd_backlight(lcd_t *lcd) {
	lcd->backlight = LCD_BACKLIGHT;
	lcd_expander_write(lcd, 0);
}

void lcd_no_backlight(lcd_t *lcd) {
	lcd->backlight = LCD_NOBACKLIGHT;
	lcd_expander_write(lcd, 0);
}

void lcd_clear(lcd_t *lcd) {
	lcd_command(lcd, LCD_CLEARDISPLAY);
	Delay_Us(2000);
}

void lcd_home(lcd_t *lcd) {
	lcd_command(lcd, LCD_RETURNHOME);
	Delay_Us(2000);
}

void lcd_cursor(lcd_t *lcd, uint8_t col, uint8_t row) {
	uint8_t row_offsets[] = {0x00, 0x40, 0x14, 0x54};
	lcd_command(lcd, LCD_SETDDRAMADDR | (col + row_offsets[row]));
}

void lcd_expander_write(lcd_t *lcd, uint8_t data) {
	while(I2C_GetFlagStatus(I2C1, I2C_FLAG_BUSY) != RESET);
	I2C_GenerateSTART(I2C1, ENABLE);
//	Delay_Ms(1);

	while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));
//	I2C_Send7bitAddress(I2C1, 0x4E, I2C_Direction_Receiver);
	I2C_SendData(I2C1, lcd->address << 1);
//	Delay_Ms(1);

	while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));

//	I2C_SendData(I2C1, 0x27);
//	while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
	I2C_SendData(I2C1, data | lcd->backlight);
//	Delay_Ms(1);
	while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));

	I2C_GenerateSTOP(I2C1, ENABLE);
//	Delay_Ms(1);
}

void lcd_write4bits(lcd_t *lcd, uint8_t value) {
	lcd_expander_write(lcd, value);

	lcd_expander_write(lcd, value | LCD_EN);
	Delay_Us(1);

	lcd_expander_write(lcd, value & ~LCD_EN);
	Delay_Us(50);
}

void lcd_command(lcd_t *lcd, uint8_t cmd) {
	lcd_write4bits(lcd, cmd & 0xF0);
	lcd_write4bits(lcd, cmd << 4);
}

void lcd_write(lcd_t *lcd, char c) {
	lcd_write4bits(lcd, (c & 0xF0) | LCD_RS);
	lcd_write4bits(lcd, (c << 4)   | LCD_RS);
}

void lcd_puts(lcd_t *lcd, char *str) {
	while(*str)
		lcd_write(lcd, *str++);
}