//
//   ^ Vcc   MSP430G2452      GND              ^ Vcc                   ^ Vcc
//   |     /-------------\     |               |                       |
//   +--- -| Vcc  U  GND |- ---+              | | 47 k                === 100 nF
//      0 -| P1.0   XTAL |- ------+ Crystal   | |                      |
//      1 -| P1.1   XTAL |- --|O|-+ 32768 Hz   |                      --- GND
//      2 -| P1.2   TEST |- -------------------|--o TEST   +--------+
//      3 -| P1.3   ~RST |- -------------------+--o ~RST   |        |
//      4 -| P1.4   P1.7 |- BUTTON_1 connected to Vcc      |       === 10 uF
//      5 -| P1.5   P1.6 |---------------------------------+        |
//      6 -| P2.0   P2.5 |- BUTTON_2 connected to Vcc      | LED    - /| Coil-
//      7 -| P2.1   P2.4 |- SR_RCK (latch clock)        / \|/      | | | Speaker
//  SR_SI -| P2.2   P2.3 |- SR_SCK (shift clock)       v/ ---       - \| (16 R)
//         \-------------/                             v   |        |
//   0..7 LED row select                                  --- GND  --- GND
//
//
//   Vcc               Vcc  +----------------+         Vcc
//     ^     SI   RCK    ^  |      Vcc ^     |    RCK    ^
//     |  Al | GND | SCK |  |          |  Ar | GND | SCK |
//     |  |  |  |  |  |  |  |          |  |  |  |  |  |  |  |
//   /------------------------\      /------------------------\
//   |Vcc QA SI OE      RST H |      |Vcc QA SI OE      RST H |
//   |>       MC74HC595       |      |>       MC74HC595       |
//   |QB QC QD QE QF QG QH GND|      |QB QC QD QE QF QG QH GND|
//   \------------------------/      \------------------------/
//     |  |  |  |  |  |  |  |          |  |  |  |  |  |  |  |
//     Bl Cl Dl El Fl Gl Hl GND        Br Cr Dr Er Fr Gr Hr GND
//      (left 8 LED columns)            (right 8 LED columns)
//
//
//     A B C D E F G H
//   0 o o o o o o o o         * A      C *
//   1 o o o o o o o o       4 *        F *
//   2 o o o o o o o o       2 *          * 3   the label is on
//   3 o o o o o o o o         * D      H *     the right side:
//   4 o o o o o o o o       7 *          * 5   (LD788BS-SS22)
//   5 o o o o o o o o         * B        * 6
//   6 o o o o o o o o       1 *        G *
//   7 o o o o o o o o       0 *        E *
//
//   0..7 (-) cathode        pin assignment as
//   A..H (+) anode          seen from the top

#include <stdint.h>

#include <msp430g2452.h>

#include "glyphs.h"
#include "tune.h"

#define SR_SI BIT2 // Serial Data Input
#define SR_SCK BIT3 // Clock Input
#define SR_RCK BIT4 // Storage Register Clock Input

#define BUZZER BIT6
#define BUTTON_1 BIT7
#define BUTTON_2 BIT5

#define DISPLAYING_LIMIT 3 // Seconds
#define SHINING_LIMIT 60 // Seconds
#define SHINING_WARN_TICKS 4

static uint8_t fb[ 16 ]; // LED frame buffer
static volatile uint8_t ticks = 0, seconds = 0, minutes = 0, hours = 0;
static volatile uint8_t alarm_hour = 0, alarm_minute = 0;
static volatile uint8_t ticks_at_button_press = 0;
static volatile uint8_t displaying_watchdog = 0;
static volatile uint8_t shining_watchdog = 0;
static volatile bool alarm_is_active = false;
static volatile bool go_to_sleep = false;
static volatile bool tick_happened = false;
static volatile uint16_t tune_index = 0;
static volatile uint8_t tune_count = 0;

enum TState { SLEEPING, SHINING,
			  TIME_DISPLAYING, TIME_HOUR_EDITING, TIME_MINUTE_EDITING,
			  ALARM_DISPLAYING, ALARM_HOUR_EDITING, ALARM_MINUTE_EDITING,
			  ALARM_IS_ACTIVE_DISPLAYING, ALARM_IS_ACTIVE_EDITING,
			  BLINKING, PLAYING };
static volatile TState state = TIME_DISPLAYING;

static void config_registers()
{
	WDTCTL = WDTPW | WDTHOLD;

	DCOCTL = CALDCO_16MHZ;
	BCSCTL1 = CALBC1_16MHZ;

	BCSCTL3 |= LFXT1S_0 | XCAP_3; // Use Crystal as ACLK + 12.5 pF caps

	WDTCTL = WDT_ADLY_16; // Interval timer mode using ACLK clock source
	IE1 |= WDTIE;

	P1OUT = 0x00;
	P2OUT = 0x00;
	P1DIR = 0xFF & ~BUTTON_1 & ~BUZZER; // All output except BUTTON_1 and BUZZER
	P2DIR = 0xFF & ~BUTTON_2; // All output except BUTTON_2

	P1OUT &= ~BUTTON_1; // select resistor to be pull-down
	P2OUT &= ~BUTTON_2;
	P1REN |= BUTTON_1; // enable resistor
	P2REN |= BUTTON_2;
	//P1IES &= ~BUTTON_1; // select the positive edge (low -> high transition) to cause an interrupt
	//P2IES &= ~BUTTON_2;
	//P1IFG &= ~BUTTON_1; // Clear any pending interrupt flags
	//P2IFG &= ~BUTTON_2;
	//P1IE |= BUTTON_1; // enable button interrupt
	//P2IE |= BUTTON_2;

	P1SEL |= BIT6; // enable Timer0_A Out1 function
	TACCTL1 = OUTMOD_7; // Reset/set  |~~|_____
	TACTL = TASSEL_2 | MC_1 | TACLR; // SMCLK + Up mode + Clear timer

	TACCR0 = 1; // period
	TACCR1 = 0; // 2 is permanent on, 0 is off when TACCR0 is 1.
}

static uint8_t shift_row( int8_t y )
{
	uint8_t on_led_count = 0;
	P2OUT &= ~SR_RCK;
	for ( uint8_t x = 0; x < 16; ++x ) {
		P2OUT &= ~SR_SCK;
		if ( fb[ 15 - x ] & ( 0x01 << y ) ) {
			P2OUT |= SR_SI;
			++on_led_count;
		} else {
			P2OUT &= ~SR_SI;
		}
		P2OUT |= SR_SCK;
	}
	return on_led_count;
}

static void select_row( int8_t  y )
{
	// Turn all rows off:
	P1OUT |= 0x3F;
	P2OUT |= 0x03;
	// Strobe columns:
	P2OUT |= SR_RCK;
	// Select respective row:
	if ( y >= 0 ) {
		if ( y < 6 ) {
			P1OUT &= ~( 0x01 << y );
		} else {
			P2OUT &= ~( 0x01 << ( y - 6 ) );
		}
	}
}

static void sleep()
{
	// Set columns low:
	P2OUT &= ~SR_RCK;
	for ( uint8_t x = 0; x < 16; ++x ) {
		P2OUT &= ~SR_SCK;
		P2OUT &= ~SR_SI;
		P2OUT |= SR_SCK;
	}
	// Strobe columns:
	P2OUT |= SR_RCK;
	// Set rows low:
	P1OUT &= ~0x3F;
	P2OUT &= ~0x03;
	// Set the rest low:
	P2OUT &= ~( SR_SI | SR_SCK | SR_RCK );
	TACCR0 = 1;
	TACCR1 = 0;              // Discharge the 10 uF capacitor, otherwise the
	__delay_cycles( 16000 ); // device consumes over 40 uA in sleep mode.
	// Change Buzzer to input:
	P1DIR &= ~BUZZER;
	// Go to sleep:
	LPM3;
}

static void clear_fb()
{
	for ( uint8_t i = 0; i < sizeof( fb ); ++i ) {
		fb[ i ] = 0;
	}
}

static void on_fb()
{
	fb[  0 ] = 0x00;
	fb[  1 ] = 0x3C;
	fb[  2 ] = 0x24;
	fb[  3 ] = 0x3C;
	fb[  4 ] = 0x42;
	fb[  5 ] = 0x81;
	fb[  6 ] = 0xFF;
	fb[  7 ] = 0x00;
	fb[  8 ] = 0x00;
	fb[  9 ] = 0x24;
	fb[ 10 ] = 0x18;
	fb[ 11 ] = 0x42;
	fb[ 12 ] = 0x3C;
	fb[ 13 ] = 0x81;
	fb[ 14 ] = 0x7E;
	fb[ 15 ] = 0x00;
}

static void off_fb()
{
	fb[  0 ] = 0x00;
	fb[  1 ] = 0x3C;
	fb[  2 ] = 0x24;
	fb[  3 ] = 0x3C;
	fb[  4 ] = 0x42;
	fb[  5 ] = 0x81;
	fb[  6 ] = 0xFF;
	fb[  7 ] = 0x00;
	fb[  8 ] = 0x00;
	fb[  9 ] = 0x42;
	fb[ 10 ] = 0x24;
	fb[ 11 ] = 0x18;
	fb[ 12 ] = 0x18;
	fb[ 13 ] = 0x24;
	fb[ 14 ] = 0x42;
	fb[ 15 ] = 0x00;
}

static void render_fb()
{
	const bool is_off_interval = ( ticks - ticks_at_button_press + 64 ) % 64 > 32;

	if ( ( state == PLAYING && ticks > 32 ) ||
		 ( state == ALARM_IS_ACTIVE_EDITING && is_off_interval ) )
	{
		clear_fb();
		return;
	}

	uint8_t hour, minute;
	bool display_blinking_point = false;
	switch ( state ) {
	case TIME_DISPLAYING:
	case TIME_HOUR_EDITING:
	case TIME_MINUTE_EDITING:
	case BLINKING:
	case PLAYING:
		hour = hours;
		minute = minutes;
		display_blinking_point = true;
		break;
	case ALARM_DISPLAYING:
	case ALARM_HOUR_EDITING:
	case ALARM_MINUTE_EDITING:
		hour = alarm_hour;
		minute = alarm_minute;
		break;
	}
	if ( state == ALARM_IS_ACTIVE_DISPLAYING || state == ALARM_IS_ACTIVE_EDITING ) {
		if ( alarm_is_active ) {
			on_fb();
		} else {
			off_fb();
		}
	} else {
		uint8_t digit_1 = hour / 10;
		uint8_t digit_2 = hour % 10;
		uint8_t digit_3 = minute / 10;
		uint8_t digit_4 = minute % 10;
		if ( ( state == TIME_HOUR_EDITING || state == ALARM_HOUR_EDITING ) && is_off_interval ) {
			digit_1 = digit_2 = 10; // none
		} else if ( digit_1 == 0 ) {
			digit_1 = 10; // none
		}
		if ( ( state == TIME_MINUTE_EDITING || state == ALARM_MINUTE_EDITING ) && is_off_interval ) {
			digit_3 = digit_4 = 10; // none
		}
		fb[  0 ] = glyph[ digit_1 ][ 0 ];
		fb[  1 ] = glyph[ digit_1 ][ 1 ];
		fb[  2 ] = glyph[ digit_1 ][ 2 ];
		fb[  3 ] = 0;
		fb[  4 ] = glyph[ digit_2 ][ 0 ];
		fb[  5 ] = glyph[ digit_2 ][ 1 ];
		fb[  6 ] = glyph[ digit_2 ][ 2 ];
		fb[  7 ] = 0;
		fb[  8 ] = 0;
		fb[  9 ] = glyph[ digit_3 ][ 0 ];
		fb[ 10 ] = glyph[ digit_3 ][ 1 ];
		fb[ 11 ] = glyph[ digit_3 ][ 2 ];
		fb[ 12 ] = 0;
		fb[ 13 ] = glyph[ digit_4 ][ 0 ];
		fb[ 14 ] = glyph[ digit_4 ][ 1 ];
		fb[ 15 ] = glyph[ digit_4 ][ 2 ];

		if ( display_blinking_point && ticks < 32 ) {
			fb[ seconds >> 2 ] |= 192;
		}

		if ( alarm_is_active ) {
			fb[ 15 ] |= 192;
		}
	}
}

static void display_fb()
{
	for ( int8_t y = 7; y >= 0; --y ) {
		uint8_t on_led_count = shift_row( y ) + 2; // Without adding some value, single dots are to dark.
		const uint8_t max_led_count = 14;
		if ( on_led_count > max_led_count ) {
			on_led_count = max_led_count;
		}
		select_row( y );
		const uint16_t delay = 357; // 16E6 / ( 300 * 14(=max_led_count) ) / 8 rows = 400.16 Hz
		for ( uint8_t i = 0; i < on_led_count; ++i ) {
			__delay_cycles( delay );
		}
		select_row( -1 );
		for ( uint8_t i = 0; i < max_led_count - on_led_count; ++i ) {
			__delay_cycles( delay );
		}
	}
}

int main( void )
{
	config_registers();
	clear_fb();
	_enable_interrupts();

	while ( true ) {
		if ( go_to_sleep ) {
			go_to_sleep = false;
			state = SLEEPING;
			sleep();
		}
		if ( tick_happened ) {
			tick_happened = false;
			switch ( state ) {
			case SHINING:
				if ( shining_watchdog + SHINING_WARN_TICKS > SHINING_LIMIT ) {
					TACCR1 = ticks == 0 ? 0 : 2;
				}
				break;
			case BLINKING:
				if ( seconds < 30 ) {
					TACCR1 = seconds % 2 ? 0 : 2;
				} else {
					TACCR1 = ( ticks & 0x0F ) == 0 ? 2 : 0;
				}
				break;
			case PLAYING:
				if ( ( ticks & 0x01 ) == 0 ) {
					const uint16_t period = scale[ tune[ tune_index ] ];
					TACCR0 = period;
					TACCR1 = period >> 1;
					++tune_index;
					if ( tune_index == sizeof( tune ) ) {
						tune_index = 0; // be kind, rewind :)
						++tune_count;
						if ( tune_count == 2 ) {
							tune_count = 0 ;
							go_to_sleep = true; // All attempts were in vain.
						}
					}
				}
				break;
			}
			render_fb();
		}
		if ( state != SHINING ) {
			display_fb(); // Does busy waiting.
		}
	}
}

#pragma vector = WDT_VECTOR
__interrupt void WDT_ISR( void )
{
	// called 64 times per second.  Consumes about 2.6 uA @ 3.3 V.  Device works down to 2.4 V.

	tick_happened = true;
	++ticks;
	if ( ticks == 64 ) {
		ticks = 0;
		++seconds;
		if ( seconds == 60 ) {
			seconds = 0;
			++minutes;
			if ( minutes == 60 ) {
				minutes = 0;
				++hours;
				if ( hours == 24 ) {
					hours = 0;
					//seconds = 1; // correction for too slow quarz
					__delay_cycles( 16000000 ); // correction for too fast quarz
				}
			}
			if ( alarm_is_active && hours == alarm_hour && minutes == alarm_minute ) {
				state = BLINKING;
				P1DIR |= BUZZER;
				TACCR0 = 1;
				TACCR1 = 0; // 2 is permanent on, 0 is off when TACCR0 is 1.
				LPM3_EXIT;
			} else if ( state == BLINKING ) {
				state = PLAYING; // Play a delightful tune.
				tune_index = 0;
			}
		}
		switch ( state ) {
		case TIME_DISPLAYING:
		case ALARM_IS_ACTIVE_DISPLAYING:
		case ALARM_DISPLAYING:
			++displaying_watchdog;
			if ( displaying_watchdog > DISPLAYING_LIMIT ) {
				go_to_sleep = true;
			}
			break;
		case SHINING:
			++shining_watchdog;
			if ( shining_watchdog > SHINING_LIMIT ) {
				go_to_sleep = true;
			}
			break;
		}

	}

	enum TButtonState { RELEASED, PRESSED, HELD };
	static volatile TButtonState button1_state = RELEASED;
	if ( ( P1IN & BUTTON_1 ) == BUTTON_1 ) {
		if ( button1_state == RELEASED ) {
			button1_state = PRESSED;
			switch ( state ) {
			case SLEEPING:
				state = TIME_DISPLAYING;
				LPM3_EXIT;
				break;
			case SHINING:
				if ( shining_watchdog + SHINING_WARN_TICKS > SHINING_LIMIT ) {
					shining_watchdog = 0;
				} else {
					go_to_sleep = true;
				}
				break;
			case TIME_DISPLAYING:
				state = alarm_is_active ? ALARM_DISPLAYING : ALARM_IS_ACTIVE_DISPLAYING;
				break;
			case ALARM_IS_ACTIVE_DISPLAYING:
			case ALARM_DISPLAYING:
				go_to_sleep = true;
				break;
			case TIME_HOUR_EDITING:
				hours = ++hours;
				if ( hours == 24 ) {
					hours = 0;
				}
				break;
			case TIME_MINUTE_EDITING:
				minutes = ++minutes;
				if ( minutes == 60 ) {
					minutes = 0;
				}
				seconds = 0;
				ticks = 0;
				break;
			case ALARM_IS_ACTIVE_EDITING:
				alarm_is_active ^= 1;
				break;
			case ALARM_HOUR_EDITING:
				alarm_hour = ++alarm_hour;
				if ( alarm_hour == 24 ) {
					alarm_hour = 0;
				}
				break;
			case ALARM_MINUTE_EDITING:
				alarm_minute = alarm_minute + 5;
				if ( alarm_minute == 60 ) {
					alarm_minute = 0;
				}
				break;
			case BLINKING:
			case PLAYING:
				go_to_sleep = true;
				break;
			}
			displaying_watchdog = 0;
			ticks_at_button_press = ticks;
		} else if ( button1_state == HELD && ( ( ticks & 0x07 ) == 0 ) ) {
			switch ( state ) {
			case TIME_HOUR_EDITING:
				hours = ++hours;
				if ( hours == 24 ) {
					hours = 0;
				}
				break;
			case TIME_MINUTE_EDITING:
				minutes = ++minutes;
				if ( minutes == 60 ) {
					minutes = 0;
				}
				seconds = 0;
				ticks = 0;
				break;
			case ALARM_HOUR_EDITING:
				alarm_hour = ++alarm_hour;
				if ( alarm_hour == 24 ) {
					alarm_hour = 0;
				}
				break;
			case ALARM_MINUTE_EDITING:
				alarm_minute = alarm_minute + 5;
				if ( alarm_minute == 60 ) {
					alarm_minute = 0;
				}
				break;
			}
			displaying_watchdog = 0;
			ticks_at_button_press = ticks;
		} else if ( ( ticks - ticks_at_button_press + 64 ) % 64 > 24 ) {
			button1_state = HELD;
		}
	} else {
		button1_state = RELEASED;
	}

	static volatile TButtonState button2_state = RELEASED;
	if ( ( P2IN & BUTTON_2 ) == BUTTON_2 ) {
		if ( button2_state == RELEASED ) {
			button2_state = PRESSED;
			bool start_blinking_with_OFF_period = true;
			switch ( state ) {
			case SLEEPING:
				state = SHINING; // Consumes about 20 mA in SHINING state.
				P1DIR |= BUZZER;
				TACCR0 = 1;
				TACCR1 = 2; // 2 is permanent on, 0 is off when TACCR0 is 1.
				shining_watchdog = 0;
				LPM3_EXIT;
				break;
			case SHINING:
				if ( shining_watchdog + SHINING_WARN_TICKS > SHINING_LIMIT ) {
					shining_watchdog = 0;
				} else {
					go_to_sleep = true;
				}
				break;
			case TIME_DISPLAYING:
				state = TIME_HOUR_EDITING;
				break;
			case TIME_HOUR_EDITING:
				state = TIME_MINUTE_EDITING;
				break;
			case TIME_MINUTE_EDITING:
				state = TIME_DISPLAYING;
				break;
			case ALARM_DISPLAYING:
				start_blinking_with_OFF_period = false;
				// Fall through intended.
			case ALARM_IS_ACTIVE_DISPLAYING:
				state = ALARM_IS_ACTIVE_EDITING;
				break;
			case ALARM_IS_ACTIVE_EDITING:
				state = alarm_is_active ? ALARM_HOUR_EDITING : ALARM_IS_ACTIVE_DISPLAYING;
				start_blinking_with_OFF_period = false;
				break;
			case ALARM_HOUR_EDITING:
				state = ALARM_MINUTE_EDITING;
				break;
			case ALARM_MINUTE_EDITING:
				//state = ALARM_IS_ACTIVE_DISPLAYING;
				state = ALARM_DISPLAYING;
				break;
			case BLINKING:
			case PLAYING:
				go_to_sleep = true;
				break;
			}
			displaying_watchdog = 0;
			if ( start_blinking_with_OFF_period ) {
				//ticks_at_button_press = ( ticks + 31 ) % 64; // immediately off for 1/2 second           ____|~~~~|____|~~
				ticks_at_button_press = ( ticks + 16 ) % 64; // first off time is 1/4 second             __|~~~~|____|~~~~
			} else {
				//ticks_at_button_press = ticks;               // immediately on for 1/2 second            ~~~~|____|~~~~|__
				ticks_at_button_press = ( ticks + 48 ) % 64; // 1/4 second delay before blinking starts  ~~|____|~~~~|____
			}
		}
	} else {
		button2_state = RELEASED;
	}

	// The interrupt flag is cleared automatically.
}

#pragma vector = PORT1_VECTOR
__interrupt void PORT1_ISR( void )
{
	//P1IFG &= ~BUTTON_1; // clear the interrupt flag
}

#pragma vector = PORT2_VECTOR
__interrupt void PORT2_ISR( void )
{
	//P2IFG &= ~BUTTON_2; // clear the interrupt flag
}

#pragma vector = USI_VECTOR
__interrupt void USI_ISR( void ) {}

#pragma vector = ADC10_VECTOR
__interrupt void ADC10_ISR( void ) {}

#pragma vector = TIMER0_A1_VECTOR
__interrupt void TIMER0_A1_ISR( void ) {}

#pragma vector = TIMER0_A0_VECTOR
__interrupt void TIMER0_A0_ISR( void ) {}

#pragma vector = COMPARATORA_VECTOR
__interrupt void COMPARATORA_ISR( void ) {}

#pragma vector = NMI_VECTOR
__interrupt void NMI_ISR( void ) {}