APSF
//- For each plan object, compute viewable period.
//- "Viewable period" is defined as the period during which the 
//- object is above a given altitude, between given times, and, 
//- optionally, when the moon is not visible or below a given 
//- % illumination).
//- The result/s are placed in user-defined fields.
//-
//- Paul Rodman, Dec 2007
//-
//- V1.0   18 Dec 2007
//-   Initial release.
//- V1.1   19 Dec 2007
//-   Fixed a bug that prevented longer lists of objects from being
//-   completely processed.
//- V1.2   12 Feb 2008
//-   Add ability to select highlighted objects only, etc.

dim doMoon as boolean
dim mIllum,pStart,pEnd,objAlt as double
dim nStart,nEnd,nVH,nVS,nVE,which as integer

dim t(-1),vs,ve,whichs(-1) as string
dim d,mrise,mset,srise(3),sset(3),periodFrom,periodTo,dFrom,dTo,dStart,dBefore,dBegin(-1),dEnd(-1) as double
dim iobj as integer, ob,olist(-1) as APPlanObject
dim viewable as double
dim cancelled as boolean

const steps = 6.0  // 6 minute steps (the smaller the step, the longer the process)
const dtime = 0.5  // Increase this if all objects are not getting processed

// Initialise parameters
doMoon = true
mIllum = 5.0
nStart=3
nEnd=3
pStart=20.0
pEnd=5.0
objAlt=20.0
nVH=1
nVS=2
nVE=3
which=0

// Restore parameters from last run
which = RestoreIntegerValue("which",which)
doMoon = RestoreBooleanValue("doMoon",doMoon)
mIllum = RestoreDoubleValue("mIllum",mIllum)
nStart = RestoreIntegerValue("nStart",nStart)
nEnd = RestoreIntegerValue("nEnd",nEnd)
pStart = RestoreDoubleValue("pStart",pStart)
pEnd = RestoreDoubleValue("pEnd",pEnd)
objAlt = RestoreDoubleValue("objAlt",objAlt)
nVH = RestoreIntegerValue("nVH",nVH)
nVS = RestoreIntegerValue("nVS",nVS)
nVE = RestoreIntegerValue("nVE",nVE)


// Get parameters
whichs.Append "All "+str(nObj)+" objects"
if nHighlighted>0 then 
  whichs.Append "All "+str(nHighlighted)+" highlighted objects"
else
  if which=1 then which=0
end if
if nObj>nHighlighted then 
  whichs.Append "All "+str(nObj-nHighlighted)+" unhighlighted objects"
else
  if which=2 then which=0
end if
if SelectedObject>0 then 
  whichs.Append "Selected object only"
else
  if which=3 then which=0
end if

SetChoiceParameter("Which objects to process",which,whichs)
SetBooleanParameter("Take moon into account",doMoon)
SetDoubleParameter("Moon illumination (%) greater than",mIllum,0.0,100.0)
ParameterDependency("Moon illumination (%) greater than","Take moon into account")

redim t(-1)
t.Append "Sunset"
t.Append "End of Civil twilight"
t.Append "End of Nautical twilight"
t.Append "End of Astronomical twilight"
t.Append "Given Start Time"
SetPopupParameter("Observing period start",nStart,t)
SetTimeParameter("Start time (if applicable)",pStart)

redim t(-1)
t.Append "Sunrise"
t.Append "Start of Civil twilight"
t.Append "Start of Nautical twilight"
t.Append "Start of Astronomical twilight"
t.Append "Given End Time"
SetPopupParameter("Observing period end",nEnd,t)
SetTimeParameter("End time (if applicable)",pEnd)

SetDoubleParameter("Minimum object altitude ("+DegreeSymbol+")",objAlt,0.0,90.0)

redim t(-1)
t.Append "n/a"
t.Append "User Field 1"
t.Append "User Field 2"
t.Append "User Field 3"
t.Append "User Field 4"

SetPopupParameter("Put Viewable Hours into",nVH,t)
SetPopupParameter("Put Viewable Start Time into",nVS,t)
SetPopupParameter("Put Viewable End Time into",nVE,t)

if not EditParameters("Viewable Hours") then return

which=GetChoiceParameter("Which objects to process")
doMoon=GetBooleanParameter("Take moon into account")
mIllum=GetDoubleParameter("Moon illumination (%) greater than")
nStart=GetPopupParameter("Observing period start")
pStart=GetTimeParameter("Start time (if applicable)")
nEnd=GetPopupParameter("Observing period end")
pEnd=GetTimeParameter("End time (if applicable)")
objAlt=GetDoubleParameter("Minimum object altitude ("+DegreeSymbol+")")
nVH=GetPopupParameter("Put Viewable Hours into")
nVS=GetPopupParameter("Put Viewable Start Time into")
nVE=GetPopupParameter("Put Viewable End Time into")

// Get the requisite objects
for iobj=1 to nObj
  select case which
  case 0
    olist.Append Obj(iobj)
  case 1
    if Obj(iobj).IsHighlighted then olist.Append Obj(iobj)
  case 2
    if not Obj(iobj).IsHighlighted then olist.Append Obj(iobj)
  case 2
    if SelectedObject=iobj then olist.Append Obj(iobj)
  end select
next

// Find the time limits

d=PlanLocalDateTime
dStart = MakeDate(YearOfDate(d),MonthOfDate(d),DayOfDate(d))-12.0*3600.0

// Get observing period start
if nStart>=4 then 
  periodFrom=pStart
else
  // Sunset today
  sset=Sunset(d)
  periodFrom=sset(nStart)
end if

// Get observing period end
if nEnd>=4 then
  periodTo=pEnd
  if periodTo<periodFrom then periodTo=periodTo+24.0
else
  // Sunrise tomorrow
  srise=SunRise(d+24*3600.0)
  periodTo=srise(nEnd)+24.0
end if

// Adjust for moon where required
if doMoon then
  if MoonIllumination(d)>mIllum*0.01 then
    // Moonrise today
    mrise=Moonrise(d)
    // Moonset today
    mset=Moonset(d)
    if mrise>0.0 and mrise>mset then mset=Moonset(d+24*3600.0)+24.0
    
    // Check various scenarios
    // moon rises/sets outside period
    if mset<periodFrom or mrise>periodTo then
      // No change to period, moon doesn't rise
    elseif mrise<periodFrom and mset<periodTo then
      // Last part of period OK
      periodFrom=mset
    elseif mrise>periodFrom and mset>periodTo then
      // First part of period OK
      periodTo=mrise
    elseif mrise>periodFrom and mset<periodTo then
      // moon rises and sets mid period
      periodTo=mrise
    else
      // Moon always risen
      periodTo=periodFrom
    end if
  end if
end if

dFrom=dStart+periodFrom*3600.0
dTo=dStart+periodTo*3600.0

redim dBegin(ubound(olist))
redim dEnd(ubound(olist))

for iobj=0 to ubound(olist)
  dBegin(iobj)=-1.0
  dEnd(iobj)=-1.0
next

StartProgress("Computing viewability",true,dTo-dFrom)
// Iterate over obs period
d=dFrom
if FixedDate then dBefore=PlanLocalDateTime else dBefore=0.0
while d<=dTo
  if UpdateProgress(d-dFrom) then
    cancelled=true
    exit
  end if
  // Fix the date
  PlanLocalDateTime=d
  Delay(0.5)
  // Loop for each object in the plan document
  for iobj=0 to ubound(olist)
    ob=olist(iobj)
    // Check altitude of object
    if ob.Altitude>=objAlt then
      if dBegin(iobj)<0.0 then dBegin(iobj)=d
      if dBegin(iobj)>=0.0 then dEnd(iobj)=d
    end if
  next
  d=d+steps*60.0
wend
PlanLocalDateTime=dBefore

if not Cancelled then
  // Put stuff into user-defined columns
  if nVH>0 then UserHeading(nVH)="Viewable Period"
  if nVS>0 then UserHeading(nVS)="Viewable Start"
  if nVE>0 then UserHeading(nVE)="Viewable End"

  for iobj=0 to ubound(olist)
    ob=olist(iobj)
    if dBegin(iobj)<0.0 then
      viewable=0.0
      vs="n/a"
      ve="n/a"
    else
      viewable=(dEnd(iobj)-dBegin(iobj))/3600.0
      vs=DoubleToTime(dBegin(iobj),false)
      ve=DoubleToTime(dEnd(iobj),false)
    end if
    if nVH>0 then ob.User(nVH)=format(viewable,"0.0")
    if nVS>0 then ob.User(nVS)=vs
    if nVE>0 then ob.User(nVE)=ve
  next
end if
StopProgress

// Save parameters for next run
SaveIntegerValue("which",which)
SaveBooleanValue("doMoon",doMoon)
SaveDoubleValue("mIllum",mIllum)
SaveIntegerValue("nStart",nStart)
SaveIntegerValue("nEnd",nEnd)
SaveDoubleValue("pStart",pStart)
SaveDoubleValue("pEnd",pEnd)
SaveDoubleValue("objAlt",objAlt)
SaveIntegerValue("nVH",nVH)
SaveIntegerValue("nVS",nVS)
SaveIntegerValue("nVE",nVE)

Bleep