/* Name: main.c
 * Author: <insert your name here>
 * Copyright: <insert your copyright message here>
 * License: <insert your license reference here>
 */

#include <stdio.h>
#include <string.h>
#include <stddef.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/sleep.h>
#include <util/delay.h>
#include <avr/pgmspace.h>
#include <avr/eeprom.h>
#include <util/crc16.h>

// for DWORD of get_fattime()
#include "integer.h"

#include "simple_ds18b20.h"
#include "onewire.h"

// configuration params
// - measurement interval
// - transmit interval
// - bluetooth params
// - number of sensors (and range?)

// 1 second. we have 1024 prescaler, 32768 crystal.
#define SLEEP_COMPARE 32
#define MEASURE_WAKE 60

#define VALUE_NOSENSOR -9000
#define VALUE_BROKEN -8000

#define COMMS_WAKE 3600

#define BAUD 19200
#define UBRR ((F_CPU)/8/(BAUD)-1)

#define PORT_LED PORTC
#define DDR_LED DDRC
#define PIN_LED PC4

#define NUM_MEASUREMENTS 100
#define MAX_SENSORS 5

int uart_putchar(char c, FILE *stream);
static FILE mystdout = FDEV_SETUP_STREAM(uart_putchar, NULL,
        _FDEV_SETUP_WRITE);

static uint16_t n_measurements = 0;
// stored as decidegrees
static int16_t measurements[MAX_SENSORS][NUM_MEASUREMENTS];

// boolean flags
static uint8_t need_measurement = 0;
static uint8_t need_comms = 0;
static uint8_t comms_done = 0;

static uint8_t readpos = 0;
static char readbuf[30];

static uint8_t measure_count = 0;
static uint16_t comms_count = 0;

// thanks to http://projectgus.com/2010/07/eeprom-access-with-arduino/
#define eeprom_read_to(dst_p, eeprom_field, dst_size) eeprom_read_block((dst_p), (void *)offsetof(struct __eeprom_data, eeprom_field), (dst_size))
#define eeprom_read(dst, eeprom_field) eeprom_read_to((&dst), eeprom_field, sizeof(dst))
#define eeprom_write_from(src_p, eeprom_field, src_size) eeprom_write_block((src_p), (void *)offsetof(struct __eeprom_data, eeprom_field), (src_size))
#define eeprom_write(src, eeprom_field) { eeprom_write_from(&src, eeprom_field, sizeof(src)); }

#define EXPECT_MAGIC 0x67c9

struct __attribute__ ((__packed__)) __eeprom_data {
    uint16_t magic;
    uint8_t n_sensors;
    uint8_t sensor_id[MAX_SENSORS][8];
};

#define DEBUG(str) printf_P(PSTR(str))

static void deep_sleep();

static void 
uart_on()
{
    // Power reduction register
    //PRR &= ~_BV(PRUSART0);
 
    // baud rate
    UBRR0H = (unsigned char)(UBRR >> 8);
    UBRR0L = (unsigned char)UBRR;
    // set 2x clock, improves accuracy of UBRR
    UCSR0A |= _BV(U2X0);
    UCSR0B = _BV(RXCIE0) | _BV(RXEN0) | _BV(TXEN0);
    //8N1
    UCSR0C = _BV(UCSZ01) | _BV(UCSZ00);
}

static void 
uart_off()
{
    // Turn of interrupts and disable tx/rx
    UCSR0B = 0;

    // Power reduction register
    //PRR |= _BV(PRUSART0);
}

int 
uart_putchar(char c, FILE *stream)
{
    // XXX should sleep in the loop for power.
    if (c == '\n')
    {
        loop_until_bit_is_set(UCSR0A, UDRE0);
        UDR0 = '\r';;
    }
    loop_until_bit_is_set(UCSR0A, UDRE0);
    UDR0 = c;
    if (c == '\r')
    {
        loop_until_bit_is_set(UCSR0A, UDRE0);
        UDR0 = '\n';;
    }
    return 0;
}

static void
cmd_fetch()
{
    uint16_t crc = 0;
    uint16_t sens;
    eeprom_read(sens, n_sensors);

    printf_P(PSTR("%d measurements\n"), n_measurements);
    for (uint16_t i = 0; i < n_measurements; i++)
    {
        printf_P(PSTR("%3d :"), i);
        for (uint8_t s = 0; s < sens; s++)
        {
            printf_P(PSTR(" %6d"), measurements[s][i]);
            crc = _crc_ccitt_update(crc, measurements[s][i]);
        }
        putchar('\n');
    }
    printf_P(PSTR("CRC : %d\n"), crc);
}

static void
cmd_clear()
{
    n_measurements = 0;
    printf_P(PSTR("Cleared\n"));
}

static void
cmd_btoff()
{
    printf_P(PSTR("Turning off\n"));
    _delay_ms(50);
	comms_done = 1;
}

static void
cmd_measure()
{
    printf_P(PSTR("Measuring\n"));
    need_measurement = 1;
}

static void
cmd_sensors()
{
    uint8_t ret = simple_ds18b20_start_meas(NULL);
    printf_P(("All sensors, ret %d, waiting...\n"), ret);
    _delay_ms(DS18B20_TCONV_12BIT);
    simple_ds18b20_read_all();
}

// 0 on success
static uint8_t
get_hex_string(const char *hex, uint8_t *out, uint8_t size)
{
    uint8_t upper;
    uint8_t o;
    for (uint8_t i = 0, z = 0; o < size; i++)
    {
        uint8_t h = hex[i];
        if (h >= 'A' && h <= 'F')
        {
            // lower case
            h += 0x20;
        }
        uint8_t nibble;
        if (h >= '0' && h <= '9')
        {
            nibble = h - '0';
        }
        else if (h >= 'a' && h <= 'f')
        {
            nibble = 10 + h - 'a';
        }
        else if (h == ' ' || h == ':')
        {
            continue;
        }
        else
        {
            printf_P(PSTR("Bad hex 0x%x '%c'\n"), hex[i], hex[i]);
            return 1;
        }

        if (z % 2 == 0)
        {
            upper = nibble << 4;
        }
        else
        {
            out[o] = upper | nibble;
            o++;
        }

        z++;
    }

    if (o != size)
    {
        printf_P(PSTR("Short hex\n"));
        return 1;
    }
    return 0;
}

static void
add_sensor(uint8_t *id)
{
    uint8_t n;
    eeprom_read(n, n_sensors);
    if (n < MAX_SENSORS)
    {
        cli();
        eeprom_write_from(id, sensor_id[n], 8);
        n++;
        eeprom_write(n, n_sensors);
        sei();
        printf_P(PSTR("Added sensor %d : "), n);
        printhex(id, 8);
        putchar('\n');
    }
    else
    {
        printf_P(PSTR("Too many sensors\n"));
    }
}

static void
cmd_add_all()
{
	uint8_t id[OW_ROMCODE_SIZE];
	uint8_t sp[DS18X20_SP_SIZE];
    printf_P("Adding all\n");
    ow_reset();
	for( uint8_t diff = OW_SEARCH_FIRST; diff != OW_LAST_DEVICE; )
	{
		diff = ow_rom_search( diff, &id[0] );
		if( diff == OW_PRESENCE_ERR ) {
			printf_P( PSTR("No Sensor found\r") );
			return;
		}
		
		if( diff == OW_DATA_ERR ) {
			printf_P( PSTR("Bus Error\r") );
			return;
		}
        add_sensor(id);
    }
}

static void
cmd_add_sensor(const char* hex_addr)
{
    uint8_t id[8];
    uint8_t ret = get_hex_string(hex_addr, id, 8);
    if (ret)
    {
        return;
    }
    add_sensor(id);

}

static void
cmd_init()
{
    printf_P(PSTR("Resetting sensor list\n"));
    uint8_t zero = 0;
    cli();
    eeprom_write(zero, n_sensors);
    sei();
    printf_P(PSTR("Done.\n"));
}

static void
check_first_startup()
{
    uint16_t magic;
    eeprom_read(magic, magic);
    if (magic != EXPECT_MAGIC)
    {
        printf_P(PSTR("First boot, looking for sensors...\n"));
        cmd_init();
        cmd_add_all();
    }
}

static void
read_handler()
{
    if (strcmp_P(readbuf, PSTR("fetch")) == 0)
    {
        cmd_fetch();
    }
    else if (strcmp_P(readbuf, PSTR("clear")) == 0)
    {
        cmd_clear();
    }
    else if (strcmp_P(readbuf, PSTR("btoff")) == 0)
    {
        cmd_btoff();
    }
    else if (strcmp_P(readbuf, PSTR("measure")) == 0)
    {
        cmd_measure();
    }
    else if (strcmp_P(readbuf, PSTR("sensors")) == 0)
    {
        cmd_sensors();
    }
    else if (strncmp_P(readbuf, PSTR("adds "), strlen("adds ")) == 0)
    {
        cmd_add_sensor(readbuf + strlen("adds "));
    }
    else if (strcmp_P(readbuf, PSTR("addall"))== 0)
    {
        cmd_add_all();
    }
    else if (strcmp_P(readbuf, PSTR("init")) == 0)
    {
        cmd_init();
    }
    else
    {
        printf_P(PSTR("Bad command\n"));
    }
}

ISR(USART_RX_vect)
{
    char c = UDR0;
    uart_putchar(c, NULL);
    if (c == '\r')
    {
        readbuf[readpos] = '\0';
        read_handler();
        readpos = 0;
    }
    else
    {
        readbuf[readpos] = c;
        readpos++;
        if (readpos >= sizeof(readbuf))
        {
            readpos = 0;
        }
    }
}

ISR(TIMER2_COMPA_vect)
{
    measure_count ++;
	comms_count ++;
    printf("measure_count %d\n", measure_count);
    if (measure_count == MEASURE_WAKE)
    {
        measure_count = 0;
        printf("need_measurement = 1\n");
        need_measurement = 1;
    }

	if (comms_count == COMMS_WAKE)
	{
		comms_count = 0;
		need_comms = 1;
	}
}

DWORD get_fattime (void)
{
    return 0;
}

static void
deep_sleep()
{
    // p119 of manual
    OCR2A = SLEEP_COMPARE;
    loop_until_bit_is_clear(ASSR, OCR2AUB);

    set_sleep_mode(SLEEP_MODE_PWR_SAVE);
    sleep_mode();
}

static void
idle_sleep()
{
    set_sleep_mode(SLEEP_MODE_IDLE);
    sleep_mode();
}

static void 
do_adc_335()
{
    //PRR &= ~_BV(PRADC);

    ADMUX = _BV(ADLAR);

    // ADPS2 = /16 prescaler, 62khz at 1mhz clock
    ADCSRA = _BV(ADEN) | _BV(ADPS2);
    
    // measure value
    ADCSRA |= _BV(ADSC);
    loop_until_bit_is_clear(ADCSRA, ADSC);
    uint8_t low = ADCL;
    uint8_t high = ADCH;
    uint16_t f_measure = low + (high << 8);

    // set to measure 1.1 reference
    ADMUX = _BV(ADLAR) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
    ADCSRA |= _BV(ADSC);
    loop_until_bit_is_clear(ADCSRA, ADSC);
    uint8_t low_11 = ADCL;
    uint8_t high_11 = ADCH;
    uint16_t f_11 = low_11 + (high_11 << 8);

    float res_volts = 1.1 * f_measure / f_11;

    // 10mV/degree
    // scale to 1/5 degree units above 0C
    int temp = (res_volts - 2.73) * 500;
    // XXX fixme
    //measurements[n_measurements] = temp;
    // XXX something if it hits the limit

    // measure AVR internal temperature against 1.1 ref.
    ADMUX = _BV(ADLAR) | _BV(MUX3) | _BV(REFS1) | _BV(REFS0);
    ADCSRA |= _BV(ADSC);
    loop_until_bit_is_clear(ADCSRA, ADSC);
    uint16_t res_internal = ADCL;
    res_internal |= ADCH << 8;

    float internal_volts = res_internal * (1.1 / 1024.0);

    // 1mV/degree
    int internal_temp = (internal_volts - 2.73) * 5000;
    // XXX fixme
    //internal_measurements[n_measurements] = internal_temp;

    printf_P("measure %d: external %d, internal %d, 1.1 %d\n",
            n_measurements, temp, internal_temp, f_11);

    n_measurements++;
    //PRR |= _BV(PRADC);
}

static void
do_measurement()
{
    uint8_t n_sensors;
    eeprom_read(n_sensors, n_sensors);

    uint8_t ret = simple_ds18b20_start_meas(NULL);
    printf_P(("Read all sensors, ret %d, waiting...\n"), ret);
    _delay_ms(DS18B20_TCONV_12BIT);

    if (n_measurements == NUM_MEASUREMENTS)
    {
        printf_P(PSTR("Measurements overflow\n"));
        n_measurements = 0;
    }

    for (uint8_t n = 0; n < MAX_SENSORS; n++)
    {
        int16_t decicelsius;
        if (n >= n_sensors)
        {
            decicelsius = VALUE_NOSENSOR;
        }
        else
        {
            uint8_t id[8];
            eeprom_read_to(id, sensor_id[n], 8);

            uint8_t ret = simple_ds18b20_read_decicelsius(id, &decicelsius);
            if (ret != DS18X20_OK)
            {
                decicelsius = VALUE_BROKEN;
            }
        }
        measurements[n_measurements][n] = decicelsius;
    }
    //do_adc_335();
}

static void
do_comms()
{
	need_comms = 0;

	// turn on bluetooth
    uart_on();
	
	// write sd card here? same 3.3v regulator...
	
    printf("ready> \n");

	comms_done = 0;
	for (;;)
	{
		if (comms_done)
		{
			break;
		}

        if (need_measurement)
        {
            do_measurement();
        }

		idle_sleep();
	}

    uart_off();

	// turn off bluetooth
}

static void
blink()
{
    PORT_LED &= ~_BV(PIN_LED);
    _delay_ms(1);
    PORT_LED |= _BV(PIN_LED);
}

#if 0
static void
long_delay(int ms)
{
    int iter = ms / 100;

    for (int i = 0; i < iter; i++)
    {
        _delay_ms(100);
    }
}
#endif

ISR(BADISR_vect)
{
    uart_on();
    printf_P(PSTR("Bad interrupt\n"));
}

static void
set_2mhz()
{
    cli();
    CLKPR = _BV(CLKPCE);
    // divide by 4
    CLKPR = _BV(CLKPS1);
    sei();
}

int main(void)
{
    set_2mhz();

    DDR_LED |= _BV(PIN_LED);
    blink();

    stdout = &mystdout;
    uart_on();

    fprintf_P(&mystdout, PSTR("hello %d\n"), 12);

    check_first_startup();

    uart_off();

    // turn off everything except timer2
    //PRR = _BV(PRTWI) | _BV(PRTIM0) | _BV(PRTIM1) | _BV(PRSPI) | _BV(PRUSART0) | _BV(PRADC);

    // for testing
    uart_on();

    sei();

    // set up counter2. 
    // COM21 COM20 Set OC2 on Compare Match (p116)
    // WGM21 Clear counter on compare
    TCCR2A = _BV(COM2A1) | _BV(COM2A0);// | _BV(WGM21);
    // CS22 CS21 CS20  clk/1024
    TCCR2B = _BV(CS22) | _BV(CS21) | _BV(CS20);
    // set async mode
    ASSR |= _BV(AS2);
    // interrupt
    TIMSK2 = _BV(OCIE2A);

    for (;;)
    {
        do_comms();
    }

    for(;;){
        /* insert your main loop code here */
        if (need_measurement)
        {
            do_measurement();
			continue;
        }

        if (need_comms)
        {
            do_comms();
			continue;
        }

		deep_sleep();
        blink();
        printf(".");
    }

    return 0;   /* never reached */
}