====== Invoicing details ======

======== Reading sessions ======== 
  * Replace empty projects with "Other"
  * If 'Used start' is empty, set it to 'Booked start'
  * If 'Booked length' is 0 (which happens e.g. if a user extends a session without booking for it), 'Booked start' is set to 'Used start'

======== Invoicing calendars ========

  * Calculations are based on PPMS' report no 16 (Session detail's report).
  * First, sort all entries according to systems.
  * Merge consecutive sessions, if
    * it's the same user
    * the same group
    * both sessions are assisted
    * Note: it's not required that both sessions are in the same project, because if someone extends a session without booking, the project isn't set.
    * Create a calendar (.ics) file for each system, which shows the **actual used time** of each session, i.e. the part that is billed. It also contains cancelled sessions. Price information is shown in the description. These files can be opened e.g. in Thunderbird via File>Open>Calendar file.


========= Excel sheets =========
  * For each project, a folder is created
  * For each group therein, a excel file is created with a sheet per system
  * Price details see below.

========= Word documents =========
  * For each group, a word document containing the invoice is created, by replacing keywords in a template with the corresponding information.
  * Two different templates exist and are used, depending whether the invoice is for the SFB1181 or not.

========= Calculating the prices =========
  * As described above, consecutive sessions are merged first
  * Prices for each individual session are calculated as follows:
  * Start and length of a session are in general the actual used time. If it's a cancelled session, it is the booked time
  * Calculate the number of minutes which are during the night
  * Calculate the number of minutes which remain at night starting 6 hours after the session start: This is the time period which will obtain a rebate for long-term imaging.
  * Calculate the number of minutes during the day
  * If a session is cancelled less than 24h before session start, 75% of the normal price are billed.
  * For all groups contributing a system (see below), if the sessions' system is not their own instrument, the price is reduced to 50% (if it's their own system, they don't need to pay anything).


========= Contributing groups =========
  * Leica SP 5 II (Upright):
    * group-mfrasch
    * group-rruebsam
    * group-aschambony
    * group-mschoppmeier
    * group-ireim
    * group-mklingler
  * Leica SP5 II (Inverted)
    * group-usonne
    * group-ssonne
    * group-bkrenz
    * group-chkoch
  * Zeiss LSM700, Zeiss Apotome
    * group-cbogdan
    * group-aluermann
    * group-dsoulat
    * group-jjantsch
    * group-mpetter
    * group-dvoehringer
    * group-rlang
    * group-skrappmann
    * group-julrich
    * group jmattner
  * Zeiss LSM 780
    * group-kzimmermann
    * group-calzheimer
    * group-kmesslinger