first draft of load/save buttons

Some considerations in the design so far:
* Desired flows:
  * start typing into a new pane, then save to a filename
  * load from a filename, then continue typing/running
  * save as a second file

* Should we autosave? I think not yet, because my editor's undo/redo
  functionality is not accessible yet on mobile. Android devices can't
  press 'ctrl', and the hotkeys aren't very discoverable.

  (I considered menu options for 'undo' and 'redo', but they won't be
  very ergonomic because my undo/redo functionality is primitive and
  doesn't support grouping similar operations. Now you're stuck tapping
  '>>', then 'undo' and losing one character. Then the menu closes and
  you have to do it all over again.)

  Another knock against autosave on mobile: autosave on quit is
  unreliable. At least on my Android devices, LÖVE doesn't trigger
  love.quit when you swipe away an app. iOS of course has no such notion
  in the first place.

* Menu buttons take up space, and I'm loath to expend 2 more buttons.
  However, I don't see a good alternative:

  * We can't use a single button to bind a filename to a pane until we
    get autosave.

  * Save on run? It doesn't save a button, but maybe we can keep 'save'
    up top because we'll want to keep hitting it in the absence of
    autosave. However, I don't want to lose data just because I started
    typing out a long program that never got to a runnable point.

* I'd like to keep 'save' always up. But newcomers might have more
  trouble finding things if load and save are separated from each other.
  Seems like the sort of thing Mike complained about before the current
  button organization.

==> conclusion: no autosave, 2 buttons, load and save

* I want to follow MiniIDE and only save to a single directory (no
  subdirectories, even). Simplifies the file dialog.

* Where should this directory live? Source base risks growing really
  large and unwieldy over time as we share files between lots of LÖVE
  apps. At least, Mike has that problem. Save dir is utterly
  inaccessible to other apps -- including later versions of this one.
  Once you delete one version of an app (say before installing a new
  version) the only way to find your files is to wade through lots of
  cryptic directories inside source dir. And you'd need a new LÖVE app
  to do that.

==> conclusion: save to a fixed subdir of source base dir. That way only
Lua Carousel will save there, but different versions share a common
space.

* Should examples be savable? If yes, we could have conflicts. If no,
  it feels like a gotcha when someone starts editing an example.

==> conclusion: allow examples to be saved, but that creates a new copy
of them on restart. It'll be weird that the order changes, but seems
like the best option.

* Where to show the current filename? I don't want to further reduce
  space for buttons. A smaller font seems necessary here to squeeze the
  filename into an interstitial of the UI.

Still to do: providing a non-existing file to load/save. I plan a
command palette UI for filtering or selecting a new file.

0011-on.initialize

@@ -1,4 +1,5 @@
 on.initialize = function()
+	App.mkdir(Directory)
 	populate_missing_handlers()
 	love.graphics.setFont(love.graphics.newFont(Font_height))
 	Line_height = math.floor(Font_height*1.3)

0012-on.draw

@@ -1,5 +1,10 @@
 on.draw = function()
 	Global_state.button_handlers = {}
+	-- modal dialog
+	if Show_file_dialog then
+		draw_file_dialog()
+		return
+	end
 	Overflow_button = nil
 	love.graphics.setBackgroundColor(Background_color.r, Background_color.g, Background_color.b)
 	draw_canvas()

0013-on.keychord_press

@@ -1,4 +1,8 @@
 on.keychord_press = function(chord, key)
+	if Show_file_dialog then
+		Show_file_dialog = false
+		return
+	end
 	if chord == 'C-=' then
 		update_font_settings(Current_pane.editor_state.font_height+2)
 	elseif chord == 'C--' then

0020-draw_editor_border

@@ -1,11 +1,26 @@
 draw_editor_border = function()
-	App.color(Normal_color)
+	App.color{r=0.5, g=0.5, b=0.5}
 	local x1 = Current_pane.editor_state.left-5-Line_number_padding
 	local y1 = Current_pane.editor_state.top-5
 	local x2 = Current_pane.editor_state.right+5
 	local y2 = Current_pane.editor_state.bottom+5
 	-- upper border
-	love.graphics.line(x1,y1, x2,y1)
+	if Current_pane.filename then
+		-- title in between if it exists
+		local old_font = love.graphics.getFont()
+		if Title_font == nil then
+			Title_font = love.graphics.newFont(15)  -- 20 pixels between menu and upper border - 5
+		end
+		love.graphics.setFont(Title_font)
+		local tx1 = Current_pane.editor_state.left
+		local tx2 = tx1 + App.width(Current_pane.filename)
+		love.graphics.print(Current_pane.filename, tx1, y1-15+5)
+		love.graphics.setFont(old_font)
+		love.graphics.line(x1,y1, tx1-5,y1)
+		love.graphics.line(math.min(tx2+5,x2), y1, x2,y1)
+	else
+		love.graphics.line(x1,y1, x2,y1)
+	end
 	love.graphics.line(x1,y1, x1,y1+10)
 	love.graphics.line(x2,y1, x2,y1+10)
 	-- lower border

0021-draw_menu

@@ -28,6 +28,8 @@ draw_menu = function()
 	else
 		x, y = show_code_button(x, y, r)
 	end
+	x, y = save_button(x, y, r)
+	x, y = load_button(x, y, r)
 	x, y = copy_button(x, y, r)
 	x, y = paste_button(x, y, r)
 	x, y = clear_pane_button(x, y, r)

0115-Title_font

@@ -0,0 +1,2 @@
+-- Lua Carousel is almost entirely in a single (adjustable) font, but we make one exception to squeeze in a file name
+Title_font = nil

0116-save_button

@@ -0,0 +1,16 @@
+save_button = function(x, y, r)
+	return overflowable_button('save', x, y, r,
+		function()
+			print('save')
+			if Current_pane.filename == nil then
+				Directory_contents = nil  -- refresh from file system
+				Show_file_dialog = true
+				File_dialog_callback = function(filename)
+					Current_pane.filename = filename
+					one_time_save()
+				end
+			else
+				one_time_save()
+			end
+		end)
+end

0117-load_button

@@ -0,0 +1,11 @@
+load_button = function(x, y, r)
+	return overflowable_button('load', x, y, r,
+		function()
+			Directory_contents = nil  -- refresh from file system
+			Show_file_dialog = true
+			File_dialog_callback = function(filename)
+				Current_pane.filename = filename
+				one_time_load()
+			end
+		end)
+end

0119-draw_file_dialog

@@ -0,0 +1,30 @@
+draw_file_dialog = function()
+	App.color(Menu_background)
+	love.graphics.rectangle('fill',
+		Menu_left+5,
+		Menu_bottom+5,
+		Safe_width-Menu_left-10,
+		Safe_height-Menu_bottom-10)
+	if Directory_contents == nil then
+		-- on the first frame after dialog is enabled
+		refresh_directory_contents()
+	end
+	local x, y = Menu_left+10, Menu_bottom+10
+	for _,filename in ipairs(Directory_contents) do
+		local w = App.width(filename) + 10
+		if x == Menu_left+10 or x+w < Safe_width-Menu_left-10 then
+			styled_button(filename, x,y, function()
+				File_dialog_callback(filename)
+				Show_file_dialog = false
+				File_dialog_callback = nil
+			end)
+			x = x+w+10
+		else
+			x = Menu_left+10
+			y = y+Line_height+10
+			if y > Safe_height-Menu_bottom-10 then
+				break
+			end
+		end
+	end
+end

0120-Show_file_dialog

@@ -0,0 +1 @@
+Show_file_dialog = false

0121-Directory

@@ -0,0 +1 @@
+Directory = love.filesystem.getSourceBaseDirectory()..'/carousel_data/'

0122-Directory_contents

@@ -0,0 +1,2 @@
+-- filenames inside directory
+Directory_contents = nil

0123-refresh_directory_contents

@@ -0,0 +1,10 @@
+refresh_directory_contents = function()
+	Directory_contents = {}
+	local files_info = nativefs.getDirectoryItemsInfo(Directory)
+	for _,file_info in ipairs(files_info) do
+		if file_info.type == 'file' then
+			table.insert(Directory_contents, file_info.name)
+		end
+	end
+	table.sort(Directory_contents)
+end

0125-File_dialog_callback

@@ -0,0 +1,2 @@
+-- Function that is called when a 'filename' is selected from the file dialog, e.g. to load from or save to a file.
+File_dialog_callback = nil

0126-one_time_save

@@ -0,0 +1,7 @@
+one_time_save = function()
+	print('saving to '..Current_pane.filename)
+	Current_pane.editor_state.filename = Directory..Current_pane.filename
+	save_to_disk(Current_pane.editor_state)
+	-- Don't autosave yet; undo isn't accessible in mobile devices.
+	Current_pane.editor_state.filename = nil
+end

0127-one_time_load

@@ -0,0 +1,8 @@
+one_time_load = function()
+	print('loading '..Current_pane.filename)
+	Current_pane.editor_state.filename = Directory..Current_pane.filename
+	load_from_disk(Current_pane.editor_state)
+	Text.redraw_all(Current_pane.editor_state)
+	-- Disable autosave; undo isn't accessible in mobile devices.
+	Current_pane.editor_state.filename = nil
+end