--*************************************************************************** 
--*************************************************************************** 
--              getUserInput() and markSpectralType() example 
--   Authors of the above functions: Don G. and Chris Laurel, respectively 
-- 
-- Shows just one of many uses for Don G.'s getUserInput() function. 
-- It asks the user to enter a star spectral class and then calls Chris' 
-- markSpectralType() function to mark all matching stars in the current 
-- Celestia database. 
-- 
-- Coded by Toti 

--*************************************************************************** 
--*************************************************************************** 


--*************************************************************************** 
--                              Constants                              
--*************************************************************************** 
-- if the script shows an error message, change this to true (remember that it will be SLOOOOOOOOOW): 
   WAIT_ENABLE   = false 

-- this controls the size of markers: 
   MARKER_SIZE   = 3 

-- A dictionary of spectral types, shape and color of the corresponding marker: 
   spectralTypes   = {O={shape="square", color="#00ff00"}, 
            B={shape="square", color="#0000ff"}, 
            A={shape="square", color="#ff0000"}, 
            F={shape="square", color="#ff00ff"}, 
            G={shape="square", color="#00ffff"}, 
            K={shape="square", color="#ffff00"}, 
            M={shape="square", color="#d0d0ff"}} 



--*************************************************************************** 
--                         Keyboard Input Callback                          
--*************************************************************************** 
function celestia_keyboard_callback(char) 
   userKeypress = char 
   return true  -- Tell Celestia we will handle this keypress 
end 



--*************************************************************************** 
--    markSpectralType function   (Chris Laurel, slightly 
--                                  adapted by Toti)          
--*************************************************************************** 
function markSpectralType(spectralType, shape, color) 
   local numOfStars   = celestia:getstarcount() 
   local counter      = 0 
   celestia:flash("Searching " .. numOfStars .. " stars...", 3) 
   while counter < numOfStars do 
      star = celestia:getstar(counter) 
      first, last = string.find(star:spectraltype(), spectralType, 1, true) 
      if first == 1 then 
         -- mod: added support for marker color, shape and size parameters: 
         star:mark(color, shape, MARKER_SIZE) 
      end 
      counter = counter + 1 
      -- mod: my computer needs these lines and WAIT_ENABLE set to true: 
      if WAIT_ENABLE then 
         wait() 
      end 
   end 
end 



--*************************************************************************** 
--                getUserInput from the keyboard     (Don G. slightly 
--                                                adapted by Toti)                  
--*************************************************************************** 
function getUserInput(prompt, uppercase) 
   local inputLine = "" 
   if prompt == nil then 
      celestia:print("getUserInput Error: Please include prompt text.",5, -1, -1, 1, 5) 
      wait(5) 
      return "" 
   end 
   origTimeScale = celestia:gettimescale()  -- Get the current time-scale 
   celestia:settimescale(0)                 -- Pause time 
   userKeypress = ""                        -- Clear the userKeypress var 
   celestia:requestkeyboard(true)           -- Enable keyboard input 
   while true do                            -- Loop until we get Enter key 
      -- Display the prompt... 
      celestia:print(prompt .. inputLine, 100, -1, -1, 1, 5) 
      wait(0.01) 
      -- What key did the user press... 
      if userKeypress == "\013" then      -- Enter key, we're done 
         break 
      elseif userKeypress == "\008" then  -- Backspace key, remove last char 
         local strlen = string.len(inputLine) 
         if strlen <= 1 then 
            inputLine = "" 
         else 
            inputLine = string.sub(inputLine, 1, strlen - 1) 
         end 
      else  -- Add the character to inputLine... 
         -- mod: support for displaying user input on uppercase (mainly of aesthetical value): 
         if uppercase == true then 
            userKeypress = string.upper(userKeypress) 
         end 
         inputLine = inputLine .. userKeypress 
      end 
      userKeypress = "" 
   end 
   celestia:requestkeyboard(false)       -- Disable keyboard input 
   celestia:settimescale(origTimeScale)  -- Reset the time scale 
   return inputLine 
end 



--*************************************************************************** 
--                       isInDict    
--            searches for an object 'obj' in the dictionary 'dict' 
--           If found, returns the object data. If not, returns nil 
--*************************************************************************** 
function isInDict(obj, dict) 
   -- try to read 'dict' data using key 'obj' 
   local block   = rawget (dict,obj) 
      if block then 
      return block 
   else 
      return nil 
   end 
end 



--*************************************************************************** 
--                  This is the main routine 
--*************************************************************************** 

-- Make sure Marker display is ON... 
celestia:show("markers") 

-- Clear all existing markers... 
celestia:unmarkall() 

repeat 
   input = getUserInput("(O B A F G K M)\n Enter spectral class and press ENTER: ", true) 

   -- do not waste CPU searching for non existing spectral classes: 
   sclass = isInDict(input, spectralTypes) 
   if sclass ~= nil then 
      markSpectralType(input, sclass.shape, sclass.color) 
   end 
   wait() 
until 1 == 2    --you must press ESC to stop this... ;)