Fix #21

Better handling of priority on done tasks
Also added <localleader>ff to fix format. this will remove leading
whitespaces and convert old (wrong) done tasks to the correct format

README.markdown

@@ -259,3 +259,7 @@ Possible values are :
 + `<LocalLeader>X` : Mark all tasks as completed
 + `<LocalLeader>D` : Move completed tasks to done file, see [TodoTxt
 Files](#todotxt-files)
+
+### Format
+
++ `<LocalLeader>ff` : Try to fix todo.txt format

autoload/todo.vim

@@ -77,6 +77,13 @@ function! todo#ToggleMarkAsDone(status)
     endif
 endfunction
 
+function! todo#FixFormat()
+    " Remove heading space
+    silent! %s/\C^\s*//
+    " Remove priority from done tasks
+    silent! %s/\C^x (\([A-Z]\)) \(.*\)/x \2 pri:\1/
+endfunction
+
 function! todo#UnMarkAsDone(status)
     if a:status==''
         let pat=''
@@ -84,12 +91,14 @@ function! todo#UnMarkAsDone(status)
         let pat=' '.a:status
     endif
     exec ':s/\C^x\s*\d\{4}-\d\{1,2}-\d\{1,2}'.pat.'\s*//g'
+    silent s/\C\(.*\) pri:\([A-Z]\)/(\2) \1/
 endfunction
 
 function! todo#MarkAsDone(status)
     if a:status!=''
         exec 'normal! I'.a:status.' '
     endif
+    exec ':s/\C^(\([A-Z]\))\(.*\)/\2 pri:\1'
     call todo#PrependDate()
     if (getline(".") =~ '^ ')
         normal! gIx

doc/todo.txt

@@ -27,6 +27,7 @@ Table of Contents                                          *TodoTxt-Contents* ~
         6.2 Priorities...............................|TodoTxt-Priorities|
         6.3 Dates....................................|TodoTxt-Dates|
         6.4 Done.txt.................................|TodoTxt-Done|
+        6.5 Format...................................|TodoTxt-Format|
 
 ===============================================================================
 1. Release notes                                       *TodoTxt-ReleaseNotes* ~
@@ -284,3 +285,7 @@ Possible values are :
     `<LocalLeader>D` : Move completed tasks to done file, see |TodoTxt-Files|
 
 `<LocalLeader>` is \ by default, so ̀`<LocaLeader>-s` means you type \s
+
+6.5 Format                                                     *TodoTxt-format*
+
+    `<LocalLeader>ff` : Try to fix todo.txt format

ftplugin/todo.vim

@@ -71,6 +71,8 @@ if !exists("g:Todo_txt_do_not_map")
 
 " Sort by due: date {{{2
     nnoremap <script> <silent> <buffer> <localleader>sd :call todo#SortDue()<CR>
+" try fix format {{{2
+    nnoremap <script> <silent> <buffer> <localleader>ff :call todo#FixFormat()<CR>
 endif
 
 " Folding {{{1

tests/todo.vader

@@ -460,7 +460,7 @@ Given todo (Tasks):
   Active task
   2017-09-01 Active task with a created date
   (A) Active priority task
-  (A) 2017-09-01 Active priority task with a created date
+  (C) 2017-09-01 Active priority task with a created date
   X 2017-09-18 Not to be confused for a complete task
   XNot to be confused for a complete task
    x 2017-09-18 Rules are not clear on leading whitespace, see comments in test
@@ -476,8 +476,8 @@ Expect todo (Toggled tasks with today as **TODAY**):
   x **TODAY** X 2017-09-18 Not to be confused for a complete task
   x **TODAY** Active task
   x **TODAY** 2017-09-01 Active task with a created date
-  x (A) **TODAY** Active priority task
+  x **TODAY** Active priority task pri:A
-  x (A) **TODAY** 2017-09-01 Active priority task with a created date
+  x **TODAY** 2017-09-01 Active priority task with a created date pri:C
   x **TODAY** X 2017-09-18 Not to be confused for a complete task
   x **TODAY** XNot to be confused for a complete task
   x **TODAY** x 2017-09-18 Rules are not clear on leading whitespace, see comments in test