// Enumerate command types
enum CommandType {
  CMD_LED,
  CMD_MOTOR,
  CMD_UNKNOWN
};

// Define a type for command handler functions
typedef void (*CommandHandler)(char *param);

// Define a structure for command entries
struct CommandEntry {
  const char *commandName;
  CommandType commandType;
  CommandHandler handler;
};

// Function prototypes
void handleLEDCommand(char *param);
void handleMotorCommand(char *param);
void showPrompt();
void toLowerCase(char *str);
long parseParameter(char *param);

// List of supported commands with function pointers
CommandEntry commandTable[] = {
  {"led", CMD_LED, handleLEDCommand},
  {"motor", CMD_MOTOR, handleMotorCommand},
};

// Number of commands in the table
const int numCommands = sizeof(commandTable) / sizeof(CommandEntry);

const int bufferSize = 50;  // Adjust the buffer size as needed
char inputBuffer[bufferSize];
int bufferIndex = 0;

void setup() {
  Serial.begin(9600);  // Start serial communication at 9600 baud rate
  pinMode(LED_BUILTIN, OUTPUT);  // Initialize built-in LED pin
  pinMode(9, OUTPUT);  // Initialize motor pin (assumed on pin 9)
  showPrompt();
}

void loop() {
  if (Serial.available() > 0) {
    char incomingChar = Serial.read();

    // Check for end of command
    if (incomingChar == '\n' || incomingChar == '\r') {
      inputBuffer[bufferIndex] = '\0';  // Null-terminate the string
      parseCommand(inputBuffer);
      bufferIndex = 0;  // Reset buffer index for the next command
      showPrompt();  // Show the prompt again after processing
    } else {
      // Add character to buffer if space permits
      if (bufferIndex < bufferSize - 1) {
        inputBuffer[bufferIndex++] = incomingChar;
      }
    }
  }
}

void parseCommand(char *command) {
  // Convert the command to lowercase for case-insensitive comparison
  toLowerCase(command);

  char *commandName = strtok(command, ":");
  char *commandParam = strtok(NULL, ":");  // If no parameter, this will be NULL

  CommandType cmdType = getCommandType(commandName);

  for (int i = 0; i < numCommands; i++) {
    if (commandTable[i].commandType == cmdType) {
      commandTable[i].handler(commandParam);  // Call the handler with the parameter (if any)
      return;
    }
  }

  Serial.println("Unknown command");
}

CommandType getCommandType(const char *commandName) {
  for (int i = 0; i < numCommands; i++) {
    if (strcmp(commandName, commandTable[i].commandName) == 0) {
      return commandTable[i].commandType;
    }
  }
  return CMD_UNKNOWN;
}

void handleLEDCommand(char *param) {
  if (param == NULL) {
    // Handle parameterless input
    int state = digitalRead(LED_BUILTIN);
    Serial.print("LED is currently ");
    Serial.println(state == HIGH ? "ON" : "OFF");
  } else {
    long ledState = parseParameter(param);
    if (ledState == 1) {
      digitalWrite(LED_BUILTIN, HIGH);  // Turn on LED
      Serial.println("LED ON");
    } else if (ledState == 0) {
      digitalWrite(LED_BUILTIN, LOW);   // Turn off LED
      Serial.println("LED OFF");
    } else {
      Serial.println("Invalid LED parameter");
    }
  }
}

void handleMotorCommand(char *param) {
  if (param == NULL) {
    // Handle parameterless input
    Serial.println("Motor speed control requires a parameter (0-255)");
  } else {
    long motorSpeed = parseParameter(param);
    if (motorSpeed >= 0 && motorSpeed <= 255) {
      analogWrite(9, motorSpeed);  // Assume motor is connected to pin 9 (PWM)
      Serial.print("Motor speed set to ");
      Serial.println(motorSpeed);
    } else {
      Serial.print("Invalid motor speed parameter - ");
      Serial.println(motorSpeed,HEX);
    }
  }
}

// Function to show the command prompt
void showPrompt() {
  Serial.print("CMD> ");
}

// Convert a string to lowercase
void toLowerCase(char *str) {
  while (*str) {
    *str = tolower(*str);
    str++;
  }
}

// Function to parse a parameter, supporting both hex ("0x") and decimal formats
long parseParameter(char *param) {
  if (param == NULL) return -1;

  if (strlen(param) > 2 && param[0] == '0' && param[1] == 'x') {
    return strtol(param, NULL, 16);  // Convert hex string to long
  } else {
    return strtol(param, NULL, 10);  // Convert decimal string to long
  }
}