Working on Date /time calculation

I am novice to Excel, and trying to work on sheet where i can track the time spent on task

Date No. level Status
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1-Dec-12 0545 1 Pending
10-Dec-12 0546 2 Pending
03-Dec-12 0547 2 Completed
20-Dec-12 0548 1 Completed


now, if level is 1 it should get completed by on same day and level 2 by next else status gets changed