Arduino DC Motor Automation

I have a simple mechanism driven by a single DC motor, and I want to hand its entire routine over to an Arduino. What I need is a clean, well-commented sketch that will: • reverse the motor on command, and • keep it running in either direction for user-defined time intervals... (Budget: ₹600 - ₹1500 INR, Jobs: Arduino, C++ Programming, Electrical Engineering, Electronics, Embedded Systems, Microcontroller, Motor Control, Robotics)