Newbie question regarding creating an extension

I’ve been using EE for some time but I’ve never created an extension before so I’m not sure if I’m able to perform the required task using an extension. I’ve listed the requirements in detail below but a quick synopsis:

1. Hook when an entry’s status is set to “open” in Channel A
2. Find the category ID for the PLAYA parent channel entry in Channel B
3. Count the number of entries in Channel B belonging to this category
4. Compare that # to the number that the user has listed in Channel A with this category ID
5. If the numbers match create an entry in a Channel C for his user and send an email notification

Any help would be appreciated.

Requirements in more detail:

Logbook Channel

Hook - when an entry’s status is set to “open”

Task

• get logbook_skill entry_id (playa field relationship with Skills channel)
• get category ID that entry_ID belongs to (skills channel)
• search logbook channel for # of entries with status “open” for this user for skills with this category ID (playa field referencing skills channel)

Skills channel

• retrieve total number of skills listed with this category ID

If total number of user entries == total number of skills with cat ID

query Achievements channel retrieving entry with the Cat ID get entry_ID for achievement

create a new entry in Achievements_Users channel - member_id - achievement entry_id - set status to open

email user that they have been awarded a new achievement badge - member_id - member email