#include <avr/io.h>
#include <util/delay.h>
#include <stdlib.h>
#include "arduinolib.h"

/* First configure the pins of arduino and then
 Initialize the LCD as described in the datasheet using the particular delays */
void Arduinolib__lcd_init_step(Arduinolib__lcd_init_out *out){
    //control pins
    LCD_E_DDR |= (1 << LCD_E_PIN);
    LCD_RS_DDR |= (1 << LCD_RS_PIN);
    //data pins
    LCD_D4_DDR |= (1 << LCD_D4_PIN);
    LCD_D5_DDR |= (1 << LCD_D5_PIN);
    LCD_D6_DDR |= (1 << LCD_D6_PIN);
    LCD_D7_DDR |= (1 << LCD_D7_PIN);

    _delay_ms(50); //power delay more than 15ms

    LCD_RS_PORT &= ~(1 << LCD_RS_PIN); //RS to low
    LCD_E_PORT &= ~(1 << LCD_E_PIN); //E to low


    // "reboot process"
    Arduinolib__lcd_write_out *o1;
    Arduinolib__lcd_write_step(LCD_FUNCTION_SET_8bit, o1);
    _delay_ms(10); //more than 4.1ms
    Arduinolib__lcd_write_out *o2;
    Arduinolib__lcd_write_step(LCD_FUNCTION_SET_8bit,o2);
    _delay_us(200); //more than 100us
    Arduinolib__lcd_write_out *o3;
    Arduinolib__lcd_write_step(LCD_FUNCTION_SET_8bit, o3);
    _delay_us(200); //more than 100us

    //set to 4bit
    Arduinolib__lcd_write_out *o4;
    Arduinolib__lcd_write_step(LCD_FUNCTION_SET_4bit, o4);
    _delay_us(80); //more than 39us
    Arduinolib__lcd_cmd_out *o5;
    Arduinolib__lcd_cmd_step(LCD_FUNCTION_SET_4bit, o5); 
    _delay_us(80); //more than 39us

    //send instructions
    Arduinolib__lcd_cmd_out *o6;
    Arduinolib__lcd_cmd_step(LCD_DISPLAY_OFF, o6);
    _delay_us(80); //more than 39us
    Arduinolib__lcd_cmd_out *o7;
    Arduinolib__lcd_cmd_step(LCD_CLEAR, o7);
    _delay_ms(3); //more than 1.53 ms
    Arduinolib__lcd_cmd_out *o8;
    Arduinolib__lcd_cmd_step(LCD_ENTRY_MODE, o8);
    _delay_us(80); //more than 39us
    Arduinolib__lcd_cmd_out *o9;
    Arduinolib__lcd_cmd_step(LCD_DISPLAY_ON, o9);
    _delay_us(80); //more than 39us

}

/* send an 8bit information to the LCD register in order to be written */
void Arduinolib__lcd_write_step(uint8_t info, Arduinolib__lcd_write_out *out){
    if (info & 1<<4){
        LCD_D4_PORT |= (1 << LCD_D4_PIN);
    }
    else {
        LCD_D4_PORT &= ~(1 << LCD_D4_PIN);
    }

    if (info & 1<<5){
        LCD_D5_PORT |= (1 << LCD_D5_PIN);
    }
    else {
        LCD_D5_PORT &= ~(1 << LCD_D5_PIN);
    }

    if (info & 1<<6){
        LCD_D6_PORT |= (1 << LCD_D6_PIN);
    }
    else {
        LCD_D6_PORT &= ~(1 << LCD_D6_PIN);
    }
    if (info & 1<<7){
        LCD_D7_PORT |= (1 << LCD_D7_PIN);
    }
    else {
        LCD_D7_PORT &= ~(1 << LCD_D7_PIN);
    }

    //pulse the Enable pin to indicate we have written the data
    LCD_E_PORT |= (1 << LCD_E_PIN); //high
    _delay_us(1);
    LCD_E_PORT &= ~(1 << LCD_E_PIN); //low
    _delay_us(1);
}

/* send an 8bit instruction(command) to the LCD instruction register */
void Arduinolib__lcd_cmd_step(uint8_t cmd, Arduinolib__lcd_cmd_out *out){

    LCD_RS_PORT &= ~(1 << LCD_RS_PIN); //low
    LCD_E_PORT &= ~(1 << LCD_E_PIN); //low
    Arduinolib__lcd_write_out *o1;
    Arduinolib__lcd_write_step(cmd, o1); // write upper 4 bits
    Arduinolib__lcd_write_out *o2;
    Arduinolib__lcd_write_step(cmd << 4, o2); // write lower 4 bits
}

/* send an 8bit data character to the LCD register */
void Arduinolib__lcd_char_step(uint8_t char_data, Arduinolib__lcd_char_out *out){

    LCD_RS_PORT |= (1 << LCD_RS_PIN); //high
    LCD_E_PORT &= ~(1 << LCD_E_PIN); //low
    Arduinolib__lcd_write_out *o1;
    Arduinolib__lcd_write_step(char_data, o1); //write upper 4 bits
    Arduinolib__lcd_write_out *o2;
    Arduinolib__lcd_write_step(char_data << 4, o2); //write lower 4 bits
}

/* give a string to display to the LCD*/ 
void Arduinolib__lcd_string_step(uint8_t lstring[], int line, Arduinolib__lcd_string_out *out){
    Arduinolib__lcd_cmd_out *o1;
    Arduinolib__lcd_cmd_out *o2;
    if (line == 1) { 
        Arduinolib__lcd_cmd_step(LCD_CURSOR_SET | LCD_START_LINE2, o1);
        _delay_us(80); //more than 39us
    } else {
        Arduinolib__lcd_cmd_step(LCD_CURSOR_SET | LCD_START_LINE1, o2);
        _delay_us(80); //more than 39us
    }
    volatile int i = 0;
    for (i = 0; lstring[i] != 0 ; i++) {
        Arduinolib__lcd_char_out *o3;
        Arduinolib__lcd_char_step(lstring[i], o3);
        _delay_us(80); //more than 39us
    }
}

/* gice a number to display to the LCD */
void Arduinolib__lcd_int_step(int numb, int line, Arduinolib__lcd_int_out *out){
    char lstring[80]; //buffer
    itoa(numb, lstring, 10);
    Arduinolib__lcd_string_out *o;
    Arduinolib__lcd_string_step(lstring, line, o);
}

/* a general read pin function. it is assuming the user uses distinct pins to read/write */
void Arduinolib__dread_step(int p, Arduinolib__dread_out *out){
    if (8 <= p && p <= 13){
        int pin = p - 8;
        DDRB &= ~(1 << pin);
        if ((PINB & (1 << pin)) == (1 << pin) ) {
            out -> v = 1; //pin high so it is pressed
        }
        else {
            out -> v = 0; //pin low so it is not pressed
        }
    }
    else if ( 0 <= p && p <= 7){
        DDRD &= ~(1 << p);
        if ((PIND & (1 << p)) == (1 << p) ) {
            out -> v = 1; //pin high so it is pressed
        } else {
            out -> v = 0; //pin low so it is not pressed
        }
    }
    else { //by default to pin 13 of arduino
        DDRB &= ~(1 << 5);
        if ((PINB & (1 << 5)) == (1 << 5) ) {
            out -> v = 1; //pin high so it is pressed
        }
        else {
            out -> v = 0; //pin low so it is not pressed
        }
    }
    return;
}

void Arduinolib__dwrite_step(int p, int v, Arduinolib__dwrite_out *out){

    if (8 <= p && p <= 13){
        int pin = p - 8;
        DDRB |= (1 << pin);
        PORTB |= (1 << pin);
        if (v == 0) PORTB &= ~(1 << pin);
    }
    else if ( 0 <= p && p <= 7){
        DDRD |= (1 << p);
        PORTD |= (1 << p);
        if (v == 0) PORTD &= ~(1 << p);
    }
    else { //by default
        DDRB |= (1 << 5);
        PORTB |= (1 << 5);
        if (v == 0) PORTB &= ~(1 << 5);
    }
    return;
}