Drupal commerce is a set of modules to help to develop an ecommerce site based on drupal7.
One of these modules is Commerce Shipping 2.x (http://drupal.org/project/commerce_shipping). Commerce Shipping provides a shipping rate calculation system for Drupal Commerce, integrating shipping service selection into both the checkout form and order edit form. This module is a framework that is meant to be used in conjunction with shipping method modules like Commerce Flat Rate, Commerce UPS, and others.
What I want you to develop is one of these shipping methods modules. The shipping rate should be calculated based on Destination Country, Destination Zip Code and Total Weight.
On the admin screen of the module you should be able to select any country and for each country have a matrix of shipping rates, in the top there should be weight ranges and in the left zip code ranges. There has to be also a column and a row meaning the rest of the values (in the image marked with a plus sign) The admin of the page should fill in the blank cells. Please see the atached image: matrix_example.
In the example, a shipping to Hungary Zip Code 12220 with a weight of 12 Kg would have a shipping rate of 20€.
Currency should be read from Drupal. Ranges can't overlap it should alert the user and ask it to be corrected.