// ATtiny85 Timeline firmware with SoftwareSerial and adjusted pins
// Charlieplex LEDs: PB2, PB3, PB4 (Pins 2, 3, 4)
// Serial via SoftwareSerial: RX = PB0, TX = PB1

#include <EEPROM.h>
#include <SoftwareSerial.h>

#define RX_PIN 0 // PB0
#define TX_PIN 1 // PB1

SoftwareSerial softSerial(RX_PIN, TX_PIN); // RX, TX

const uint8_t pinsArr[3] = {2, 3, 4}; // PB2, PB3, PB4 for Charlieplex
#define EEPROM_BASE 0

struct Frame
{
  uint8_t led;       // 0..5
  uint16_t start;    // ms
  uint16_t duration; // ms
};

#define MAX_RAM_FRAMES 32
Frame framesRAM[MAX_RAM_FRAMES];
uint8_t frameCount = 0;

void clearPins()
{
  for(uint8_t i = 0; i < 3; i++) pinMode(pinsArr[i], INPUT);
}

void setSingleLED(uint8_t led)
{
  clearPins();
  switch(led)
  {
    case 0: pinMode(pinsArr[0], OUTPUT); pinMode(pinsArr[1], OUTPUT); digitalWrite(pinsArr[0], HIGH); digitalWrite(pinsArr[1], LOW); break;
    case 1: pinMode(pinsArr[1], OUTPUT); pinMode(pinsArr[0], OUTPUT); digitalWrite(pinsArr[1], HIGH); digitalWrite(pinsArr[0], LOW); break;
    case 2: pinMode(pinsArr[1], OUTPUT); pinMode(pinsArr[2], OUTPUT); digitalWrite(pinsArr[1], HIGH); digitalWrite(pinsArr[2], LOW); break;
    case 3: pinMode(pinsArr[2], OUTPUT); pinMode(pinsArr[1], OUTPUT); digitalWrite(pinsArr[2], HIGH); digitalWrite(pinsArr[1], LOW); break;
    case 4: pinMode(pinsArr[2], OUTPUT); pinMode(pinsArr[0], OUTPUT); digitalWrite(pinsArr[2], HIGH); digitalWrite(pinsArr[0], LOW); break;
    case 5: pinMode(pinsArr[0], OUTPUT); pinMode(pinsArr[2], OUTPUT); digitalWrite(pinsArr[0], HIGH); digitalWrite(pinsArr[2], LOW); break;
    default: clearPins(); break;
  }
}

String readLine()
{
  String s = "";
  while (softSerial.available())
  {
    char c = softSerial.read();
    if(c == '\r') continue;
    if(c == '\n') break;
    s += c;
  }
  return s;
}

void saveToEEPROM()
{
  uint16_t eplen = EEPROM.length();
  uint16_t perFrame = sizeof(Frame);
  uint16_t maxFramesEEP = (eplen <= 1)?0:(eplen - 1) / perFrame;
  uint8_t toWrite = frameCount;
  if(toWrite > maxFramesEEP) toWrite=maxFramesEEP;
  EEPROM.update(EEPROM_BASE, toWrite);
  uint16_t addr = EEPROM_BASE + 1;
  for(uint8_t i = 0; i < toWrite; i++)
  {
    EEPROM.put(addr + i * perFrame, framesRAM[i]);
  }
  softSerial.println("OK SAVED");
}

void loadFromEEPROM()
{
  uint16_t eplen = EEPROM.length();
  uint16_t perFrame = sizeof(Frame);
  if(eplen <= 1){ frameCount = 0; softSerial.println("ERR EEPROM TOO SMALL"); return; }
  uint8_t cnt = 0;
  EEPROM.get(EEPROM_BASE, cnt);
  uint16_t maxFramesEEP = (eplen - 1) / perFrame;
  if(cnt > maxFramesEEP) cnt = 0;
  frameCount = cnt;
  uint16_t addr = EEPROM_BASE + 1;
  for(uint8_t i = 0; i < frameCount; i++)
  {
    EEPROM.get(addr + i * perFrame, framesRAM[i]);
  }
  softSerial.println("OK LOADED");
}

void dumpFrames()
{
  for(uint8_t i = 0; i < frameCount; i++)
  {
    softSerial.print(i); softSerial.print(": LED ");
    softSerial.print(framesRAM[i].led);
    softSerial.print(" START "); softSerial.print(framesRAM[i].start);
    softSerial.print(" DUR "); softSerial.println(framesRAM[i].duration);
  }
}

void playTimelineFromRAM()
{
  if(frameCount == 0) { softSerial.println("OK PLAYED (empty)"); return; }
  uint32_t total = 0;
  for(uint8_t i = 0; i < frameCount; i++)
  {
    uint32_t endt = (uint32_t)framesRAM[i].start + framesRAM[i].duration;
    if(endt > total) total = endt;
  }
  uint32_t startTime = millis();
  const uint16_t tickMs = 20, pulseMs = 4;
  while((uint32_t)(millis() - startTime) <= total)
  {
    uint32_t t = millis() - startTime;
    uint8_t activeMask = 0;
    for(uint8_t i = 0; i < frameCount; i++)
    {
      uint32_t s = framesRAM[i].start, e = s + framesRAM[i].duration;
      if((t >= s) && (t < e) && (framesRAM[i].led < 6)) activeMask |= (1 << framesRAM[i].led);
    }
    if(activeMask == 0) { clearPins(); delay(tickMs); continue; }
    for(uint8_t led = 0; led < 6; led++)
    {
      if(activeMask & (1 << led)) { setSingleLED(led); delay(pulseMs); clearPins(); }
    }
    delay(tickMs - pulseMs);
  }
  clearPins(); softSerial.println("OK PLAYED");
}

void setup()
{
  softSerial.begin(9600);
  clearPins();
  frameCount = 0;
  softSerial.println("READY");

  for(uint8_t i = 0; i < 6; i++)
  {
    setSingleLED(i);
    delay(500);
    clearPins();
  }


}

void loop()
{
  if(softSerial.available())
  {
    String line = readLine(); 
    line.trim(); 
    if(!line.length()) return;
    if(line.startsWith("ADD"))
    {
      int a,b,c; 
      int n = sscanf(line.c_str(),"ADD %d %d %d",&a,&b,&c);
      if((n == 3) && (frameCount < MAX_RAM_FRAMES) && (a >= 0) && (a < 6) && (b >= 0) && (c > 0))
      {
        framesRAM[frameCount].led = a; 
        framesRAM[frameCount].start = b; 
        framesRAM[frameCount].duration = c;
        frameCount++; 
        softSerial.println("OK ADDED");
      }
      else softSerial.println("ERR ADD");
    } 
    else if(line == "SAVE") { saveToEEPROM(); }
    else if(line == "LOAD") { loadFromEEPROM(); }
    else if(line == "DUMP") { dumpFrames(); }
    else if(line == "CLEAR") { frameCount = 0; softSerial.println("OK CLEARED"); }
    else if(line == "PLAY") { playTimelineFromRAM(); }
    else softSerial.println("ERR UNKNOWN");
  }
}