Autocompletion app for Mac OS

Need to write application which will analyze text at the any text editor component at the any Mac OS application and after a hotkey press will complete current word with words which already present in a text. For example, if we will input text from a first paragraph and I will start to input "com" and then press the hotkey, program will complete word to "complete". If I'll press hotkey one more time, word will be completed to "component". Programm sort worts to complete by density in a text & distance from current position of cursor (that's why it will offer "complete" first - it closer to cursor and both words have same density in the first paragraph). For forms program complete words from all fields of form. P. S. Such completion was implemented in Textmate (try to play with "Esc" when you do type) and some IDE's.