Menu_background_color = {r=0.6, g=0.8, b=0.6}
Menu_border_color = {r=0.6, g=0.7, b=0.6}
Menu_command_color = {r=0.2, g=0.2, b=0.2}
Menu_highlight_color = {r=0.5, g=0.7, b=0.3}

function source.draw_menu_bar()
  if App.run_tests then return end  -- disable in tests
  App.color(Menu_background_color)
  love.graphics.rectangle('fill', 0,0, App.screen.width, Menu_status_bar_height)
  App.color(Menu_border_color)
  love.graphics.rectangle('line', 0,0, App.screen.width, Menu_status_bar_height)
  App.color(Menu_command_color)
  Menu_cursor = 5
  if Show_file_navigator then
    source.draw_file_navigator()
    return
  end
  add_hotkey_to_menu('ctrl+e: run')
  if Focus == 'edit' then
    add_hotkey_to_menu('ctrl+g: switch file')
    if Show_log_browser_side then
      add_hotkey_to_menu('ctrl+l: hide log browser')
    else
      add_hotkey_to_menu('ctrl+l: show log browser')
    end
    if Editor_state.expanded then
      add_hotkey_to_menu('alt+b: collapse debug prints')
    else
      add_hotkey_to_menu('alt+b: expand debug prints')
    end
    add_hotkey_to_menu('alt+d: create/edit debug print')
    add_hotkey_to_menu('ctrl+f: find in file')
    add_hotkey_to_menu('alt+left alt+right: prev/next word')
  elseif Focus == 'log_browser' then
    -- nothing yet
  else
    assert(false, 'unknown focus "'..Focus..'"')
  end
  add_hotkey_to_menu('ctrl+z ctrl+y: undo/redo')
  add_hotkey_to_menu('ctrl+x ctrl+c ctrl+v: cut/copy/paste')
  add_hotkey_to_menu('ctrl+= ctrl+- ctrl+0: zoom')
end

function add_hotkey_to_menu(s)
  local s_text = to_text(s)
  local width = App.width(s_text)
  if Menu_cursor + width > App.screen.width - 5 then
    return
  end
  App.color(Menu_command_color)
  App.screen.draw(s_text, Menu_cursor,5)
  Menu_cursor = Menu_cursor + width + 30
end

function source.draw_file_navigator()
  App.color(Menu_command_color)
  local filter_text = to_text(File_navigation.filter)
  App.screen.draw(filter_text, 5, 5)
  draw_cursor(5 + App.width(filter_text), 5)
  if File_navigation.num_lines == nil then
    File_navigation.num_lines = source.num_lines_for_file_navigator(File_navigation.candidates)
  end
  App.color(Menu_background_color)
  love.graphics.rectangle('fill', 0,Menu_status_bar_height, App.screen.width, File_navigation.num_lines * Editor_state.line_height + --[[highlight padding]] 2)
  local x,y = 5, Menu_status_bar_height
  for i,filename in ipairs(File_navigation.candidates) do
    x,y = add_file_to_menu(x,y, filename, i == File_navigation.index)
    if Menu_cursor >= App.screen.width - 5 then
      break
    end
  end
end

function draw_cursor(x, y)
  -- blink every 0.5s
  if math.floor(Cursor_time*2)%2 == 0 then
    App.color(Cursor_color)
    love.graphics.rectangle('fill', x,y, 3,Editor_state.line_height)
  end
end

function source.file_navigator_candidates()
  if File_navigation.filter == '' then
    return File_navigation.all_candidates
  end
  local result = {}
  for _,filename in ipairs(File_navigation.all_candidates) do
    if starts_with(filename, File_navigation.filter) then
      table.insert(result, filename)
    end
  end
  return result
end

function source.num_lines_for_file_navigator(candidates)
  local result = 1
  local x = 5
  for i,filename in ipairs(candidates) do
    local width = App.width(to_text(filename))
    if x + width > App.screen.width - 5 then
      result = result+1
      x = 5 + width
    else
      x = x + width + 30
    end
  end
  return result
end

function add_file_to_menu(x,y, s, cursor_highlight)
  local s_text = to_text(s)
  local width = App.width(s_text)
  if x + width > App.screen.width - 5 then
    y = y + Editor_state.line_height
    x = 5
  end
  local color = Menu_background_color
  if cursor_highlight then
    color = Menu_highlight_color
  end
  button(Editor_state, 'menu', {x=x-5, y=y-2, w=width+5*2, h=Editor_state.line_height+2*2, color=colortable(color),
    onpress1 = function()
      navigate_to_file(s)
    end
  })
  App.color(Menu_command_color)
  App.screen.draw(s_text, x,y)
  x = x + width + 30
  return x,y
end

function navigate_to_file(s)
  move_candidate_to_front(s)
  local candidate = guess_source(s..'.lua')
  source.switch_to_file(candidate)
  reset_file_navigator()
end

function move_candidate_to_front(s)
  local index = array.find(File_navigation.all_candidates, s)
  assert(index)
  table.remove(File_navigation.all_candidates, index)
  table.insert(File_navigation.all_candidates, 1, s)
end

function reset_file_navigator()
  Show_file_navigator = false
  File_navigation.index = 1
  File_navigation.filter = ''
  File_navigation.candidates = File_navigation.all_candidates
end

function keychord_pressed_on_file_navigator(chord, key)
  log(2, 'file navigator: '..chord)
  log(2, {name='file_navigator_state', files=File_navigation.candidates, index=File_navigation.index})
  if chord == 'escape' then
    reset_file_navigator()
  elseif chord == 'return' then
    navigate_to_file(File_navigation.candidates[File_navigation.index])
  elseif chord == 'backspace' then
    local len = utf8.len(File_navigation.filter)
    local byte_offset = Text.offset(File_navigation.filter, len)
    File_navigation.filter = string.sub(File_navigation.filter, 1, byte_offset-1)
    File_navigation.index = 1
    File_navigation.candidates = source.file_navigator_candidates()
  elseif chord == 'left' then
    if File_navigation.index > 1 then
      File_navigation.index = File_navigation.index-1
    end
  elseif chord == 'right' then
    if File_navigation.index < #File_navigation.candidates then
      File_navigation.index = File_navigation.index+1
    end
  elseif chord == 'down' then
    file_navigator_down()
  elseif chord == 'up' then
    file_navigator_up()
  end
end

function log_render.file_navigator_state(o, x,y, w)
  -- duplicate structure of source.draw_file_navigator
  local num_lines = source.num_lines_for_file_navigator(o.files)
  local h = num_lines * Editor_state.line_height
  App.color(Menu_background_color)
  love.graphics.rectangle('fill', x,y, w,h)
  -- compute the x,y,width of the current index (in offsets from top left)
  local x2,y2 = 0,0
  local width = 0
  for i,filename in ipairs(o.files) do
    local filename_text = to_text(filename)
    width = App.width(filename_text)
    if x2 + width > App.screen.width - 5 then
      y2 = y2 + Editor_state.line_height
      x2 = 0
    end
    if i == o.index then
      break
    end
    x2 = x2 + width + 30
  end
  -- figure out how much of the menu to display
  local menu_xmin = math.max(0, x2-w/2)
  local menu_xmax = math.min(App.screen.width, x2+w/2)
  -- now selectively print out entries
  local x3,y3 = 0,y  -- x3 is relative, y3 is absolute
  local width = 0
  for i,filename in ipairs(o.files) do
    local filename_text = to_text(filename)
    width = App.width(filename_text)
    if x3 + width > App.screen.width - 5 then
      y3 = y3 + Editor_state.line_height
      x3 = 0
    end
    if i == o.index then
      App.color(Menu_highlight_color)
      love.graphics.rectangle('fill', x + x3-menu_xmin - 5, y3-2, width+5*2, Editor_state.line_height+2*2)
    end
    if x3 >= menu_xmin and x3 + width < menu_xmax then
      App.color(Menu_command_color)
      App.screen.draw(filename_text, x + x3-menu_xmin, y3)
    end
    x3 = x3 + width + 30
  end
  --
  return h+20
end

function file_navigator_up()
  local y, x, width = file_coord(File_navigation.index)
  local index = file_index(y-Editor_state.line_height, x, width)
  if index then
    File_navigation.index = index
  end
end

function file_navigator_down()
  local y, x, width = file_coord(File_navigation.index)
  local index = file_index(y+Editor_state.line_height, x, width)
  if index then
    File_navigation.index = index
  end
end

function file_coord(index)
  local y,x = Menu_status_bar_height, 5
  for i,filename in ipairs(File_navigation.candidates) do
    local width = App.width(to_text(filename))
    if x + width > App.screen.width - 5 then
      y = y + Editor_state.line_height
      x = 5
    end
    if i == index then
    return y, x, width
    end
    x = x + width + 30
  end
end

function file_index(fy, fx, fwidth)
  log_start('file index')
  log(2, ('for %d %d %d'):format(fy, fx, fwidth))
  local y,x = Menu_status_bar_height, 5
  local best_guess, best_guess_x, best_guess_width
  for i,filename in ipairs(File_navigation.candidates) do
    local width = App.width(to_text(filename))
    if x + width > App.screen.width - 5 then
      y = y + Editor_state.line_height
      x = 5
    end
    if y == fy then
      log(2, ('%d: correct row; considering %d %s %d %d'):format(y, i, filename, x, width))
      if best_guess == nil then
        log(2, 'nil')
        best_guess = i
        best_guess_x = x
        best_guess_width = width
      elseif math.abs(fx + fwidth/2 - x - width/2) < math.abs(fx + fwidth/2 - best_guess_x - best_guess_width/2) then
        best_guess = i
        best_guess_x = x
        best_guess_width = width
      end
      log(2, ('best guess now %d %s %d %d'):format(best_guess, File_navigation.candidates[best_guess], best_guess_x, best_guess_width))
    end
    x = x + width + 30
  end
  log_end('file index')
  return best_guess
end

function textinput_on_file_navigator(t)
  File_navigation.filter = File_navigation.filter..t
  File_navigation.candidates = source.file_navigator_candidates()
end