bugfix: inscript's bug

To fix this I have to first stop incrementally updating screen_bottom1
in the middle of a frame. Now it always has a good value from the end of
a frame.

I'm also running into some limitations in the test I'd ideally like to
write (that are documented in a comment), but I still get some sort of
automated test for this bugfix.

4 files changed, 65 insertions, 16 deletions

diff --git a/edit.lua b/edit.lua
index 5918165..f436f36 100644
--- a/edit.lua
+++ b/edit.lua
@@ -152,12 +152,13 @@ function edit.draw(State)
   State.cursor_x = nil
   State.cursor_y = nil
   local y = State.top
+  local screen_bottom1 = {line=nil, pos=nil}
 --?   print('== draw')
   for line_index = State.screen_top1.line,#State.lines do
     local line = State.lines[line_index]
 --?     print('draw:', y, line_index, line)
     if y + State.line_height > App.screen.height then break end
-    State.screen_bottom1 = {line=line_index, pos=nil}
+    screen_bottom1.line = line_index
     if line.mode == 'text' then
 --?       print('text.draw', y, line_index)
       local startpos = 1
@@ -180,7 +181,7 @@ function edit.draw(State)
                      end,
         })
       end
-      y, State.screen_bottom1.pos = Text.draw(State, line_index, y, startpos)
+      y, screen_bottom1.pos = Text.draw(State, line_index, y, startpos)
 --?       print('=> y', y)
     elseif line.mode == 'drawing' then
       y = y+Drawing_padding_top
@@ -191,6 +192,7 @@ function edit.draw(State)
       assert(false)
     end
   end
+  State.screen_bottom1 = screen_bottom1
   if State.search_term then
     Text.draw_search_bar(State)
   end
@@ -221,7 +223,7 @@ end
 
 function edit.mouse_press(State, x,y, mouse_button)
   if State.search_term then return end
-  print_and_log(('edit.mouse_press: cursor at %d,%d'):format(State.cursor1.line, State.cursor1.pos))
+--?   print_and_log(('edit.mouse_press: cursor at %d,%d'):format(State.cursor1.line, State.cursor1.pos))
   if mouse_press_consumed_by_any_button_handler(State, x,y, mouse_button) then
     -- press on a button and it returned 'true' to short-circuit
     return
@@ -258,7 +260,7 @@ function edit.mouse_press(State, x,y, mouse_button)
             line=line_index,
             pos=Text.to_pos_on_line(State, line_index, x, y),
         }
-        break
+        return
       end
     elseif line.mode == 'drawing' then
       local line_cache = State.line_cache[line_index]
@@ -267,15 +269,24 @@ function edit.mouse_press(State, x,y, mouse_button)
         State.lines.current_drawing = line
         Drawing.before = snapshot(State, line_index)
         Drawing.mouse_press(State, line_index, x,y, mouse_button)
-        break
+        return
       end
     end
   end
+
+  -- still here? click is below all screen lines
+  State.old_cursor1 = State.cursor1
+  State.old_selection1 = State.selection1
+  State.mousepress_shift = App.shift_down()
+  State.selection1 = {
+      line=State.screen_bottom1.line,
+      pos=Text.pos_at_end_of_screen_line(State, State.screen_bottom1),
+  }
 end
 
 function edit.mouse_release(State, x,y, mouse_button)
   if State.search_term then return end
-  print_and_log(('edit.mouse_release: cursor at %d,%d'):format(State.cursor1.line, State.cursor1.pos))
+--?   print_and_log(('edit.mouse_release: cursor at %d,%d'):format(State.cursor1.line, State.cursor1.pos))
   if State.lines.current_drawing then
     Drawing.mouse_release(State, x,y, mouse_button)
     schedule_save(State)
@@ -284,16 +295,16 @@ function edit.mouse_release(State, x,y, mouse_button)
       Drawing.before = nil
     end
   else
-    print_and_log('edit.mouse_release: no current drawing')
+--?     print_and_log('edit.mouse_release: no current drawing')
     for line_index,line in ipairs(State.lines) do
       if line.mode == 'text' then
         if Text.in_line(State, line_index, x,y) then
-          print_and_log(('edit.mouse_release: in line %d'):format(line_index))
+--?           print_and_log(('edit.mouse_release: in line %d'):format(line_index))
           State.cursor1 = {
               line=line_index,
               pos=Text.to_pos_on_line(State, line_index, x, y),
           }
-          print_and_log(('edit.mouse_release: cursor now %d,%d'):format(State.cursor1.line, State.cursor1.pos))
+--?           print_and_log(('edit.mouse_release: cursor now %d,%d'):format(State.cursor1.line, State.cursor1.pos))
           if State.mousepress_shift then
             if State.old_selection1.line == nil then
               State.selection1 = State.old_cursor1
@@ -309,7 +320,7 @@ function edit.mouse_release(State, x,y, mouse_button)
         end
       end
     end
-    print_and_log(('edit.mouse_release: finally selection %s,%s cursor %d,%d'):format(tostring(State.selection1.line), tostring(State.selection1.pos), State.cursor1.line, State.cursor1.pos))
+--?     print_and_log(('edit.mouse_release: finally selection %s,%s cursor %d,%d'):format(tostring(State.selection1.line), tostring(State.selection1.pos), State.cursor1.line, State.cursor1.pos))
   end
 end
 
diff --git a/select.lua b/select.lua
index c2fe7ad..9b2a278 100644
--- a/select.lua
+++ b/select.lua
@@ -67,13 +67,8 @@ function Text.draw_highlight(State, line, x,y, pos, lo,hi)
   end
 end
 
--- inefficient for some reason, so don't do it on every frame
 function Text.mouse_pos(State)
-  local line,pos = Text.to_pos(State, App.mouse_x(), App.mouse_y())
-  return line, pos
-end
-
-function Text.to_pos(State, x,y)
+  local x,y = App.mouse_x(), App.mouse_y()
   if y < State.line_cache[State.screen_top1.line].starty then
     return State.screen_top1.line, State.screen_top1.pos
   end
@@ -84,6 +79,7 @@ function Text.to_pos(State, x,y)
       end
     end
   end
+  return State.screen_bottom1.line, Text.pos_at_end_of_screen_line(State, State.screen_bottom1)
 end
 
 function Text.cut_selection(State)
diff --git a/text.lua b/text.lua
index b6389e4..d89fb63 100644
--- a/text.lua
+++ b/text.lua
@@ -591,6 +591,7 @@ function Text.right_without_scroll(State)
   end
 end
 
+-- result: pos, index of screen line
 function Text.pos_at_start_of_screen_line(State, loc1)
   Text.populate_screen_line_starting_pos(State, loc1.line)
   local line_cache = State.line_cache[loc1.line]
@@ -603,6 +604,20 @@ function Text.pos_at_start_of_screen_line(State, loc1)
   assert(false)
 end
 
+function Text.pos_at_end_of_screen_line(State, loc1)
+  Text.populate_screen_line_starting_pos(State, loc1.line)
+  local line_cache = State.line_cache[loc1.line]
+  local most_recent_final_pos = utf8.len(State.lines[loc1.line].data)+1
+  for i=#line_cache.screen_line_starting_pos,1,-1 do
+    local spos = line_cache.screen_line_starting_pos[i]
+    if spos <= loc1.pos then
+      return most_recent_final_pos
+    end
+    most_recent_final_pos = spos-1
+  end
+  assert(false)
+end
+
 function Text.cursor_at_final_screen_line(State)
   Text.populate_screen_line_starting_pos(State, State.cursor1.line)
   local screen_lines = State.line_cache[State.cursor1.line].screen_line_starting_pos
diff --git a/text_tests.lua b/text_tests.lua
index a01ad3e..21a085a 100644
--- a/text_tests.lua
+++ b/text_tests.lua
@@ -864,6 +864,33 @@ function test_select_text_using_mouse_starting_above_text_wrapping_line()
   check_eq(Editor_state.selection1.pos, 3, 'selection:pos')
 end
 
+function test_select_text_using_mouse_starting_below_text()
+  -- I'd like to test what happens when a mouse click is below some page of
+  -- text, potentially even in the middle of a line.
+  -- However, it's brittle to set up a text line boundary just right.
+  -- So I'm going to just check things below the bottom of the final line of
+  -- text when it's in the middle of the screen.
+  -- final screen line ends in the middle of screen
+  App.screen.init{width=50, height=60}
+  Editor_state = edit.initialize_test_state()
+  Editor_state.lines = load_array{'abcde'}
+  Text.redraw_all(Editor_state)
+  Editor_state.cursor1 = {line=1, pos=1}
+  Editor_state.screen_top1 = {line=1, pos=1}
+  Editor_state.screen_bottom1 = {}
+  edit.draw(Editor_state)
+  local y = Editor_state.top
+  App.screen.check(y, 'ab', 'baseline:screen:1')
+  y = y + Editor_state.line_height
+  App.screen.check(y, 'cde', 'baseline:screen:2')
+  -- press mouse above first line of text
+  edit.run_after_mouse_press(Editor_state, 5,App.screen.height-5, 1)
+  -- selection is past bottom-most text in screen
+  check(Editor_state.selection1.line ~= nil, 'selection:line-not-nil')
+  check_eq(Editor_state.selection1.line, 1, 'selection:line')
+  check_eq(Editor_state.selection1.pos, 6, 'selection:pos')
+end
+
 function test_select_text_using_mouse_and_shift()
   App.screen.init{width=50, height=60}
   Editor_state = edit.initialize_test_state()