PHP small module for time calculations

I need a module to attach to an exist php web app to do this thing: 1) read employee punches from mysql db (datetime plus enter/exit sense) collected by terminal for daily working hours. 2) calculate time elapsed between two punches. Punches can be across midnight (e.g. IN yesterday and OUT today), can be more of two punches per day (max 6). 3) divide time elapsed in daily or nightly hour based on clock time. 4) after n. 3), hours can be standard or extra, based on what max are standards hours for and employee in a day. Full example: - let set night hours every day are from 00:00 to 06:00 and from 20:00 to 24:00s - let set max standard daily working hours are 8. - an employee punches (time in 24h format) IN at 05:00, OUT at 10:00, IN at 18:00, OUT at 02:00 (next day) Calculation is: - nightly hours 1H (from 05:00 to 06:00) - standard hours 6H (4h from 6:00 to 10:00 plus 2h from 18:00 to 20:00) - nightly hours added to the first nightly 1H (from 20:00 to 21:00 because reach the max of day set to 8h) - extra hours 1H (from 21:00 to 22:00 because at 22:00 starts night) - extra nighly hours 4H (from 22:00 to 02:00 next day) 3) summarize in report with daily punches list, daily hours separated by nightly, daily etc type, monthly summarize. 4) if during elaboration found a day with two IN or two OUT or OUT before IN (with out not related to IN at previous day), mark relative day wrong with an asterisk and take no calculation for that day. 5) between IN and OUT can be no more of 16h. If there is IN with an OUT after 16h, mark IN day as wrong and take no calculation for that day. 6) report can be exported in html, pdf and xls As frontend framework can use bootstrap css.