implementation module shift

//import StdEnv
import StdArray, StdBool, StdChar, StdInt
import StdMaybe
import StrictList
import EdSelection, EdMonad, EdClient, EdVisualText, EdVisualCursor
from IdeState import General
import menubar
import EdCommon

// apply replace_lines_f to lines begin_line..end_line in text

//replace_lines :: (TLine -> TLine) !Int !Int !Text -> Text
replace_lines replace_line_f begin_line 0 text = text
replace_lines replace_line_f begin_line n_lines text
	#	(line,text)		= getLine begin_line text
		line			= replace_line_f line
		(_,text)		= updateLine begin_line line text
	= replace_lines replace_line_f (inc begin_line) (dec n_lines) text


n_lines_in_selection {start={row=l1},end={row=l2,col=c2}}
	| c2<=0
		= l2-l1
		= inc (l2-l1)

//replace_lines_and_redraw :: .(Int -> {#Char} -> .{#Char}) !*(PSt *General) -> *PSt *General;
replace_lines_and_redraw :: (Int -> {#Char} -> .{#Char}) !*(PSt *General) -> *PSt *General;
replace_lines_and_redraw shift_selection_f ps
	#	(_,ps)			= sendToActiveWindow localmsg ps
		ps				= mb_update_undoinfo ps
	= ps
where
	localmsg =
		getSelection												>>>= \selection ->
		let ordered_selection	= orderSelection selection
			n_lines				= n_lines_in_selection ordered_selection
		in
		IF (isEmptySelection ordered_selection || n_lines==0)
		THEN
			( skip )
		ELSE
			(
			getText													>>>= \text ->
			getFontInfo												>>>= \{tabSize} ->
			let newt = replace_lines (shift_selection_f tabSize) ordered_selection.start.row n_lines text
				(newsel,newtext) = extend_selection_to_begin_and_end_of_line ordered_selection newt
			in
			setText newtext											>>>
			// set saved state false
			vCenterCursor											>>>
			//vResetViewDomain										>>>
			vChangeSelectionTo {newsel & end = newsel.start}						>>>
			mChangeSelectionTo {newsel & end = newsel.start}						>>>
			vTextUpdate ordered_selection.start n_lines	>>>
			vChangeSelectionTo newsel								>>>
			mChangeSelectionTo newsel								>>>
			// set undo to empty undo...
			setUndoInfo {state = None, action = "", uninfo = NoInfo}	>>>
			setNeedSave True
			)

extend_selection_to_begin_and_end_of_line selection text
	| selection.end.col == 0
		= ({selection & start = {selection.start & col = 0}},text)
	#	lastline			= lastLineNr text
	| selection.end.row < lastline
		= ({start = {selection.start & col = 0}, end = {row = inc selection.end.row, col = 0}},text)
	#	(line,text)			= getLine (dec selection.end.row) text
	= ({start = {selection.start & col = 0}, end = {row = selection.end.row, col = size line}},text)

shift_selection_right :: !*(PSt General) -> *PSt General
shift_selection_right ps
	= replace_lines_and_redraw shift_line_right ps
where
	shift_line_right text_tab_width line
		= "\t" +++ line

shift_selection_left :: !*(PSt General) -> *PSt General
shift_selection_left ps
	= replace_lines_and_redraw shift_line_left ps
where
	shift_line_left :: Int String -> String
	shift_line_left text_tab_width string
		| size string == 0
			= string
		| string.[0] == '\t'
			= string % (1,dec (size string))
		# n_leading_spaces = count_spaces_at_begin 0 string
		# n_leading_spaces = min n_leading_spaces text_tab_width
		| n_leading_spaces == 0
			= string
		= string % (n_leading_spaces,dec (size string))

	count_spaces_at_begin n_spaces string
		| n_spaces < size string && string.[n_spaces] == ' '
			= count_spaces_at_begin (inc n_spaces) string
		= n_spaces