the 'flash mode' is saved in the image meta-data as a number, what does every value mean in words? How can it be parsed? is their any documentation for this?
Essentially, odd numbers meant the flash fired, even numbers (including zero) meant it did not. There are other flags in there as well, such as whether the flash was supposed to fire, and whether the returned light from a flash was detected. Different cameras support different flags, based on their capabilities.