sensor_console.cpp

#include "sensor_console.h"

namespace sensor_console {
  const uint8_t MAX_COMMANDS = 20;
  const uint8_t MAX_COMMAND_SIZE = 30;

  uint8_t commands_count = 0;

  struct Command {
    const char *name;
    union {
      void (*intFunction)(int32_t);
      void (*voidFunction)(void);
    };
    const char *doc;
    bool has_parameter;
  };

  Command commands[MAX_COMMANDS];

  //NOTE: Probably possible to DRY (with templates?)
  void defineCommand(const char *name, void (*function)(void), const __FlashStringHelper *doc_fstring) {
    const char *doc = (const char*) doc_fstring;
    if (commands_count < MAX_COMMANDS) {
      commands[commands_count].name = name;
      commands[commands_count].voidFunction = function;
      commands[commands_count].doc = doc;
      commands[commands_count].has_parameter = false;
      commands_count++;
    } else {
      Serial.println(F("Too many commands have been defined."));
    }
  }

  void defineIntCommand(const char *name, void (*function)(int32_t), const __FlashStringHelper *doc_fstring) {
    const char *doc = (const char*) doc_fstring;
    if (commands_count < MAX_COMMANDS) {
      commands[commands_count].name = name;
      commands[commands_count].intFunction = function;
      commands[commands_count].doc = doc;
      commands[commands_count].has_parameter = true;
      commands_count++;
    } else {
      Serial.println(F("Too many commands have been defined."));
    }
  }

  /*
   * Tries to split a string command (e.g. 'mqtt 60' or 'show_csv') into a function_name and an argument.
   * Returns 0 if both are found, 1 if there is a problem and 2 if no argument is found.
   */
  uint8_t parseCommand(const char *command, char *function_name, int32_t &argument) {
    char split_command[MAX_COMMAND_SIZE];
    strlcpy(split_command, command, MAX_COMMAND_SIZE);
    char *arg;
    char *part1;
    part1 = strtok(split_command, " ");
    if (!part1) {
      Serial.println(F("Received empty command"));
      // Empty string
      return 1;
    }
    strlcpy(function_name, part1, MAX_COMMAND_SIZE);
    arg = strtok(NULL, " ");
    uint8_t code = 0;
    if (arg) {
      char *end;
      argument = strtol(arg, &end, 10);
      if (*end) {
        // Second argument isn't a number
        code = 2;
      }
    } else {
      // No argument
      code = 2;
    }
    return code;
  }

  /*
   * Saves bytes from Serial.read() until enter is pressed, and tries to run the corresponding command.
   *   http://www.gammon.com.au/serial
   */
  void processSerialInput(const byte input_byte) {
    static char input_line[MAX_COMMAND_SIZE];
    static unsigned int input_pos = 0;
    switch (input_byte) {
    case '\n': // end of text
      Serial.println();
      input_line[input_pos] = 0;
      runCommand(input_line);
      input_pos = 0;
      break;
    case '\r': // discard carriage return
      break;
    case '\b': // backspace
      if (input_pos > 0) {
        input_pos--;
        Serial.print(F("\b \b"));
      }
      break;
    default:
      if (input_pos == 0) {
        Serial.print(F("> "));
      }
      // keep adding if not full ... allow for terminating null byte
      if (input_pos < (MAX_COMMAND_SIZE - 1)) {
        input_line[input_pos++] = input_byte;
        Serial.print((char) input_byte);
      }
      break;
    }
  }

  int compareName(const void *s1, const void *s2) {
    struct Command *c1 = (struct Command*) s1;
    struct Command *c2 = (struct Command*) s2;
    return strcmp(c1->name, c2->name);
  }

  void listAvailableCommands() {
    qsort(commands, commands_count, sizeof(commands[0]), compareName);
    for (uint8_t i = 0; i < commands_count; i++) {
      Serial.print("  ");
      Serial.print(commands[i].name);
      Serial.print(commands[i].doc);
      Serial.println(".");
    }
  }

  /*
   * Tries to find the corresponding callback for a given command. Name and number of argument should fit.
   */
  void runCommand(const char *command) {
    char function_name[MAX_COMMAND_SIZE];
    int32_t argument = 0;
    bool has_argument;
    has_argument = (parseCommand(command, function_name, argument) == 0);

    for (uint8_t i = 0; i < commands_count; i++) {
      if (!strcmp(function_name, commands[i].name) && has_argument == commands[i].has_parameter) {
        Serial.print(F("Calling : "));
        Serial.print(function_name);
        if (has_argument) {
          Serial.print(F("("));
          Serial.print(argument);
          Serial.println(F(")"));
          commands[i].intFunction(argument);
        } else {
          Serial.println(F("()"));
          commands[i].voidFunction();
        }
        return;
      }
    }
    Serial.print(F("'"));
    Serial.print(command);
    Serial.println(F("' not supported. Available commands :"));
    listAvailableCommands();
  }
}