fsm.pseudo.c

enum states_t {
    WAIT,         /* Wait until the soil is dry, then take action. */
    PUMP_BUFFER,  /* Pump buffer reservoir until 90% capacity.     */
    WATER_SOIL    /* Water the soil until it isn't dry anymore.    */
};

enum states_t state = WAIT;

while (1) {
    switch (state) {
        case WAIT:
            if (soil_is_dry())
                state = WATER_SOIL;

            sleep(1);
            break;

        case PUMP_BUFFER:
            // pump water into buffer for 5 seconds
            pump_buffer(5);

            // buffer is at 90% capacity... go back to watering
            if (buffer_level() > 90)
                state = WATER_SOIL;

            break;

        case WATER_SOIL:
            // buffer is close to empty... let's refill it
            if (buffer_level() < 10)
                state = PUMP_BUFFER;

            // drip irrigate for 5 minutes
            water_soil(5);

            // done watering!
            if (!soil_is_dry())
                state = WAIT;

            break;
    }

    sleep(0.25);
}