Create Photoshop CS4 script to output layers in a custom way

I have a number of Photoshop CS4 (Mac) files (psd) that contain graphics for a game. I require a script that I can run (inside photoshop) that will output PNG files for use in my game. There are some specific requirements: 1. Any layers that are linked together must be exported to the same PNG file. 2. The name of the PNG file is the name of the layer (or the first layer, if linked) 3. Text, shapes, etc, must be rasterized first. 4. If a layer contains transparency, the PNG must contain transparency. 5. If a layer (or linked layers) contain transparency, then the PNG must be cropped to the smallest possible size. 6. If text file must be written out that contains each PNG and their offset: 6b. If a layer is completely filled, or has no transparency, its offset is 0,0. 6c. If a layer contains transparency, and is cropped, its offset is the number of pixels from the top left of the canvas to the top left of the PNG. The horizontal distance should be written first (X), followed by the vertical distance. For example: > [login to view URL], 100,20 > [login to view URL], 100,40 > [login to view URL], 0,0 > A sample file is included.