/*
 * interpreter.ino: Simple Arduino command line interpreter.
 *
 * This is intended solely as a template for building richer,
 * application-specific interpreters. Add your specific commands to the
 * exec() function, and whatever you need to setup() and loop().
 *
 * Usage:
 *   Talk to it through the serial port at 9600/8N1. Commands should be
 *   terminated by CR (\r), answers are terminated by CRLF (\r\n). This
 *   should play well with typical terminal emulators. For the list of
 *   supported commands, see the answer to the "help" command.
 *
 * Copyright (c) 2016 Edgar Bonet Orozco.
 * Released under the terms of the MIT license:
 * https://opensource.org/licenses/MIT
 */

#include <avr/pgmspace.h>

#define BUF_LENGTH 128  /* Buffer for the incoming command. */

static bool do_echo = true;

/* Execute a complete command. */
static void exec(char *cmdline)
{
    char *command = strsep(&cmdline, " ");

    if (strcmp_P(command, PSTR("help")) == 0) {
        Serial.println(F(
            "mode <pin> <mode>: pinMode()\r\n"
            "read <pin>: digitalRead()\r\n"
            "aread <pin>: analogRead()\r\n"
            "write <pin> <value>: digitalWrite()\r\n"
            "awrite <pin> <value>: analogWrite()\r\n"
            "echo <value>: set echo off (0) or on (1)"));
    } else if (strcmp_P(command, PSTR("mode")) == 0) {
        int pin = atoi(strsep(&cmdline, " "));
        int mode = atoi(cmdline);
        pinMode(pin, mode);
    } else if (strcmp_P(command, PSTR("read")) == 0) {
        int pin = atoi(cmdline);
        Serial.println(digitalRead(pin));
    } else if (strcmp_P(command, PSTR("aread")) == 0) {
        int pin = atoi(cmdline);
        Serial.println(analogRead(pin));
    } else if (strcmp_P(command, PSTR("write")) == 0) {
        int pin = atoi(strsep(&cmdline, " "));
        int value = atoi(cmdline);
        digitalWrite(pin, value);
    } else if (strcmp_P(command, PSTR("awrite")) == 0) {
        int pin = atoi(strsep(&cmdline, " "));
        int value = atoi(cmdline);
        analogWrite(pin, value);
    } else if (strcmp_P(command, PSTR("echo")) == 0) {
        do_echo = atoi(cmdline);
    } else {
        Serial.print(F("Error: Unknown command: "));
        Serial.println(command);
    }
}

void setup()
{
    Serial.begin(9600);
}

void loop() {

    /* Process incoming commands. */
    while (Serial.available()) {
        static char buffer[BUF_LENGTH];
        static int length = 0;

        int data = Serial.read();
        if (data == '\b' || data == '\177') {  // BS and DEL
            if (length) {
                length--;
                if (do_echo) Serial.write("\b \b");
            }
        }
        else if (data == '\r') {
            if (do_echo) Serial.write("\r\n");    // output CRLF
            buffer[length] = '\0';
            if (length) exec(buffer);
            length = 0;
        }
        else if (length < BUF_LENGTH - 1) {
            buffer[length++] = data;
            if (do_echo) Serial.write(data);
        }
    }

    /* Whatever else needs to be done... */
}