Improvements to filetype detection, plugin loading

- Create .vim folder too if missing
- Use filetype to categorize combo instead of file extension (this will
  reset some combo counters, such as python: py.cmb -> python.cmb)
- Reload combo stats upon filetype change
- Check if combo tracking is already loaded on script start (to prevent
  multiple instances when sourcing vimrc again)
- More verbose g:combo (access numbers directly at g:combo_counter and
  g:best_combo)

To fix any lost combo score, rename the file accordingly in
~/.vim/.combo

plugin/vim-combo.vim

@@ -1,43 +1,67 @@
 " COMBO Counter
-" Choose combo file depending on extension
+
+" Check if already loaded
+if exists('g:combo_tracker_already_loaded')
+	finish
+endif
+let g:combo_tracker_already_loaded = 1
 
 " Check for a .combo folder, make one if missing
+if !isdirectory($HOME . '/.vim')
+    silent !mkdir $HOME/.vim
+endif
 if !isdirectory($HOME . '/.vim/.combo')
     silent !mkdir $HOME/.vim/.combo
 endif
-" Get extension, choose combo file
-if strlen(expand("%:e")) > 0 
-    let g:combo_file = $HOME . '/.vim/.combo/' . expand("%:e") . ".cmb"
-else
-    let g:combo_file = $HOME . '/.vim/.combo/none.cmb'
-endif
 
-" Find best score for current filetype. If none exists, start tracking
-if filereadable(g:combo_file)
+function ComboFmt()
+	return printf("combo|%d [best|%d]", g:combo, g:best_combo)
+endfunction
+
+" Get extension, choose combo file
+function ReloadComboFile()
+	let g:combo_file_type = &filetype
+	if strlen(g:combo_file_type) > 0 
+	    let g:combo_file = $HOME . '/.vim/.combo/' . g:combo_file_type . ".cmb"
+	else
+	    let g:combo_file = $HOME . '/.vim/.combo/none.cmb'
+	endif
+	
+	" Find best score for current filetype. If none exists, start tracking
+	if filereadable(g:combo_file)
 		let g:best_combo = readfile(g:combo_file)
 		let g:best_combo = g:best_combo[0]
-else
+	else
 		silent exec '!echo 0 > ' . g:combo_file
 		let g:best_combo = 0
-endif
-let g:best_last_combo = g:best_combo		" Used to revert
+	endif
+	let g:best_last_combo = g:best_combo		" Used to revert
+	let g:combo_counter = 0		" The actual combo variable
+	let g:combo = ComboFmt()
+endfunction
 
-" Configure variables
+autocmd FileType * call ReloadComboFile()
+
+" Declare variables
 let g:combo_counter = 0		" The actual combo variable
-let g:timeout = 1
-let g:combo = printf("[%d] 0", g:best_combo)
+let g:best_combo = 0		" Where best score for filetype is tracked
+let g:best_last_combo = 0	" Used to revert, when you cheat by accident
+let g:combo_timeout = 1
+let g:combo = ComboFmt()
 let g:last_combo = reltime()	" Set current time as last combo time
+
 " Main check function, executed every time the file is changed
 function! UpdateCombo()
-	if reltimefloat(reltime(g:last_combo)) > g:timeout
+	if reltimefloat(reltime(g:last_combo)) > g:combo_timeout
 		call SaveCombo()
 		let g:combo_counter = 1
 	else
 		let g:combo_counter +=1
 	endif
-	let g:combo = printf("[%d] %d", g:best_combo, g:combo_counter)
+	let g:combo = ComboFmt()
 	let g:last_combo = reltime()
 endfunction
+
 " Checks if a new combo has been achieved and saves it to file
 function! SaveCombo()		" Should check inside because it can be called on InsertLeave
 	if g:combo_counter > g:best_combo
@@ -49,15 +73,18 @@ endfunction
 
 autocmd TextChangedI * call UpdateCombo()	" Every time text is changed, call combo function
 autocmd InsertLeave * call SaveCombo()
+
 " In case you want to revert your last combo
 function! Cheated()
 	let g:best_combo = g:best_last_combo
 	let g:combo_counter = g:best_last_combo
 	call writefile([g:combo_counter], g:combo_file)
 endfunction
+
 " This is only needed to avoid backspace cheating.
 function! Decrease()
 	let g:combo_counter -= 1
 	return "\<BS>"
 endfunction
+
 inoremap <expr> <BS> Decrease()