
---------------------------------------------------------------------------
--- A modification of the ratio layout that respects spacing.
-- The default ratio layout doesn't factor in the widget spacing when
-- determining the widget size. It calculates the widget size to where
-- they sum to 100% of available space and THEN it applies the spacing,
-- causing the widgets to be pushed out of the visible area.
-- Modifications at lines 113-122.
---------------------------------------------------------------------------

local base  = require("wibox.widget.base" )
local flex  = require("wibox.layout.flex" )
local table = table
local pairs = pairs
local floor = math.floor
local gmath = require("gears.math")
local gtable = require("gears.table")
local unpack = unpack or table.unpack -- luacheck: globals unpack (compatibility with Lua 5.1)

local ratio = {}

--- The widget used to fill the spacing between the layout elements.
--
-- By default, no widget is used.
--
--@DOC_wibox_layout_ratio_spacing_widget_EXAMPLE@
--
-- @property spacing_widget
-- @tparam[opt=nil] widget|nil spacing_widget
-- @propemits true false
-- @interface layout

--- Add spacing between each layout widgets.
--
--@DOC_wibox_layout_ratio_spacing_EXAMPLE@
--
-- @property spacing
-- @tparam[opt=0] number spacing
-- @negativeallowed true
-- @propemits true false
-- @interface layout

-- Compute the sum of all ratio (ideally, it should be 1).
local function gen_sum(self, i_s, i_e)
  local sum, new_w = 0,0

  for i = i_s or 1, i_e or #self._private.widgets do
    if self._private.ratios[i] then
      sum = sum + self._private.ratios[i]
    else
      new_w = new_w + 1
    end
  end

  return sum, new_w
end

-- The ratios are expressed as percentages. For this to work, the sum of all
-- ratio must be 1. This function attempt to adjust them. Space can be taken
-- from or added to a ratio when widgets are being added or removed. If a
-- specific ratio must be enforced for a widget, it has to be done with the
-- `adjust_ratio` method after each insertion or deletion
local function normalize(self)
  local count = #self._private.widgets
  if count == 0 then return end

  -- Instead of adding "if" everywhere, just handle this common case
  if count == 1 then
    self._private.ratios = { 1 }
    return
  end

  local sum, new_w = gen_sum(self)
  local old_count  = #self._private.widgets - new_w

  local to_add = (sum == 0) and 1 or (sum / old_count)

  -- Make sure all widgets have a ratio
  for i=1, #self._private.widgets do
    if not self._private.ratios[i] then
      self._private.ratios[i] = to_add
    end
  end

  sum = sum + to_add*new_w

  local delta, new_sum =  (1 - sum) / count,0

  -- Increase or decrease each ratio so it the sum become 1
  for i=1, #self._private.widgets do
    self._private.ratios[i] = self._private.ratios[i] + delta
    new_sum = new_sum + self._private.ratios[i]
  end

  -- Floating points is not an exact science, but it should still be close
  -- to 1.00.
  assert(new_sum > 0.99 and new_sum < 1.01)
end

function ratio:layout(context, width, height)
  local preliminary_results = {}
  local pos,spacing = 0, self._private.spacing
  local strategy = self:get_inner_fill_strategy()
  local has_stragety = strategy ~= "default"
  local to_redistribute, void_count = 0, 0
  local dir = self._private.dir or "x"
  local spacing_widget = self._private.spacing_widget
  local abspace = math.abs(spacing)
  local spoffset = spacing < 0 and 0 or spacing
  local is_y = self._private.dir == "y"
  local is_x = not is_y

  -- Respect spacing!
  local count = #self._private.widgets
  if count > 1 then
    local numspaces = count - 1
    if is_y then
      height = height - (self._private.spacing * numspaces)
    else
      width = width - (self._private.spacing * numspaces)
    end
  end

  for k, v in ipairs(self._private.widgets) do
    local space, is_void
    local x, y, w, h, fit_h, fit_w

    if dir == "y" then
      space = height * self._private.ratios[k]
      x, y = 0, gmath.round(pos)
      w, h = width, floor(space)
    else
      space = width * self._private.ratios[k]
      x, y = gmath.round(pos), 0
      w, h = floor(space), height
    end

    -- Keep track of the unused entries
    if has_stragety then
      fit_h, fit_w = base.fit_widget(
        self, context, v,
        dir == "x" and floor(space) or w,
        dir == "y" and floor(space) or h
      )

      is_void = (v.visible == false)
        or (dir == "x" and fit_w == 0)
        or (dir == "y" and fit_h == 0)

      if is_void then
        to_redistribute = to_redistribute + space + spacing
        void_count = void_count + 1
      end
    end

    table.insert(preliminary_results, {v, x, y, w, h, is_void})

    pos = pos + space + spacing

    -- Make sure all widgets fit in the layout, if they aren't, something
    -- went wrong
    if (dir == "y" and gmath.round(pos) >= height) or
      (dir ~= "y" and gmath.round(pos) >= width) then
      break
    end
  end

  local active = #preliminary_results - void_count
  local result, real_pos, space_front = {}, 0, strategy == "right" and
    to_redistribute or (
      strategy == "center" and math.floor(to_redistribute/2) or 0
    )

  -- The number of spaces between `n` element is `n-1`, if there is spaces
  -- outside, then it is `n+1`
  if strategy == "spacing" then
    space_front = (space_front+to_redistribute/(active + 1))
    to_redistribute = (to_redistribute/(active + 1))*(active - 1)
  end

  spacing = strategy:match("spacing")
    and to_redistribute/(active - 1) or 0

  -- Only the `justify` strategy changes the original widget size.
  to_redistribute = (strategy == "justify") and to_redistribute or 0

  for k, entry in ipairs(preliminary_results) do
    local v, x, y, w, h, is_void = unpack(entry)

    -- Redistribute the space or move the widgets
    if strategy ~= "default" then
      if dir == "y" then
        h = is_void and 0 or h + (to_redistribute / (active))
        y = space_front + real_pos
        real_pos = real_pos + h + (is_void and 0 or spacing)

      else
        w = is_void and 0 or w + (to_redistribute / (active))
        x = space_front + real_pos
        real_pos = real_pos + w + (is_void and 0 or spacing)
      end
    end

    if k > 1 and abspace > 0 and spacing_widget then
      table.insert(result, base.place_widget_at(
        spacing_widget, is_x and (x - spoffset) or x, is_y and (y - spoffset) or y,
        is_x and abspace or w, is_y and abspace or h
      ))
    end

    table.insert(result, base.place_widget_at(v, x, y, w, h))
  end

  return result
end

--- Increase the ratio of "widget".
-- If the increment produce an invalid ratio (not between 0 and 1), the method
-- do nothing.
--
--@DOC_wibox_layout_ratio_inc_ratio_EXAMPLE@
--
-- @method inc_ratio
-- @tparam number index The widget index to change
-- @tparam number increment An floating point value between -1 and 1 where the
--   end result is within 0 and 1
-- @noreturn
function ratio:inc_ratio(index, increment)
  if #self._private.widgets ==  1 or (not index) or (not self._private.ratios[index])
    or increment < -1 or increment > 1 then
    return
  end

  assert(self._private.ratios[index])

  self:set_ratio(index, self._private.ratios[index] + increment)
end

--- Increment the ratio of the first instance of `widget`.
-- If the increment produce an invalid ratio (not between 0 and 1), the method
-- do nothing.
--
-- @method inc_widget_ratio
-- @tparam widget widget The widget to adjust
-- @tparam number increment An floating point value between -1 and 1 where the
--   end result is within 0 and 1
-- @noreturn
function ratio:inc_widget_ratio(widget, increment)
  if not widget or not increment then return end

  local index = self:index(widget)

  self:inc_ratio(index, increment)
end

--- Set the ratio of the widget at position `index`.
--
-- @method set_ratio
-- @tparam number index The index of the widget to change
-- @tparam number percent An floating point value between 0 and 1
-- @noreturn
function ratio:set_ratio(index, percent)
  if not percent or #self._private.widgets ==  1 or not index or not self._private.widgets[index]
    or percent < 0 or percent > 1 then
    return
  end

  local old = self._private.ratios[index]

  -- Remove what has to be cleared from all widget
  local delta = ( (percent-old) / (#self._private.widgets-1) )

  for k in pairs(self._private.widgets) do
    self._private.ratios[k] = self._private.ratios[k] - delta
  end

  -- Set the new ratio
  self._private.ratios[index] = percent

  -- As some widgets may now have a slightly negative ratio, normalize again
  normalize(self)

  self:emit_signal("widget::layout_changed")
end

--- Get the ratio at `index`.
--
-- @method get_ratio
-- @tparam number index The widget index to query
-- @treturn number The index (between 0 and 1)
function ratio:get_ratio(index)
  if not index then return end
  return self._private.ratios[index]
end

--- Set the ratio of `widget` to `percent`.
--
-- @method set_widget_ratio
-- @tparam widget widget The widget to adjust.
-- @tparam number percent A floating point value between 0 and 1.
-- @noreturn
function ratio:set_widget_ratio(widget, percent)
  local index = self:index(widget)

  self:set_ratio(index, percent)
end

--- Update all widgets to match a set of a ratio.
-- The sum of before, itself and after must be 1 or nothing will be done.
--
--@DOC_wibox_layout_ratio_adjust_ratio_EXAMPLE@
--
-- @method adjust_ratio
-- @tparam number index The index of the widget to change
-- @tparam number before The sum of the ratio before the widget
-- @tparam number itself The ratio for "widget"
-- @tparam number after The sum of the ratio after the widget
-- @noreturn
function ratio:adjust_ratio(index, before, itself, after)
  if not self._private.widgets[index] or not before or not itself or not after then
    return
  end

  local sum = before + itself + after

  -- As documented, it is the caller job to come up with valid numbers
  if math.min(before, itself, after) < 0 then return end
  if sum > 1.01 or sum < -0.99 then return end

  -- Compute the before and after offset to be applied to each widgets
  local before_count, after_count = index-1, #self._private.widgets - index

  local b, a = gen_sum(self, 1, index-1), gen_sum(self, index+1)

  local db, da = (before - b)/before_count, (after - a)/after_count

  -- Apply the new ratio
  self._private.ratios[index] = itself

  -- Equality split the delta among widgets before and after
  for i = 1, index -1 do
    self._private.ratios[i] = self._private.ratios[i] + db
  end
  for i = index+1, #self._private.widgets do
    self._private.ratios[i] = self._private.ratios[i] + da
  end

  -- Remove potential negative ratio
  normalize(self)

  self:emit_signal("widget::layout_changed")
end
--- Update all widgets to match a set of a ratio.
--
-- This method is kept for backwards compatibility, please use `:adjust_ratio` instead.
-- @see wibox.layout.ratio.adjust_ratio
-- @deprecated wibox.layout.ratio.ajust_ratio
-- @tparam number index The index of the widget to change
-- @tparam number before The sum of the ratio before the widget
-- @tparam number itself The ratio for "widget"
-- @tparam number after The sum of the ratio after the widget
function ratio:ajust_ratio(...)
  require('gears.debug').deprecate(
    "Use `:adjust_ratio` rather than `:ajust_ratio`",
    { deprecated_in = 5 }
  )
  self:adjust_ratio(...)
end

--- Update all widgets to match a set of a ratio.
--
-- @method adjust_widget_ratio
-- @tparam widget widget The widget to adjust
-- @tparam number before The sum of the ratio before the widget
-- @tparam number itself The ratio for "widget"
-- @tparam number after The sum of the ratio after the widget
-- @noreturn
function ratio:adjust_widget_ratio(widget, before, itself, after)
  local index = self:index(widget)
  self:adjust_ratio(index, before, itself, after)
end
--- Update all widgets to match a set of a ratio.
--
-- This method is kept for backwards compatibility, please use `:adjust_widget_ratio` instead.
-- @see wibox.layout.ratio.adjust_widget_ratio
-- @deprecated wibox.layout.ratio.ajust_widget_ratio
-- @tparam widget widget The widget to adjust
-- @tparam number before The sum of the ratio before the widget
-- @tparam number itself The ratio for "widget"
-- @tparam number after The sum of the ratio after the widget
-- @noreturn
function ratio:ajust_widget_ratio(...)
  require('gears.debug').deprecate(
    "Use `:adjust_widget_ratio` rather than `:ajust_widget_ratio`",
    { deprecated_in = 5 }
  )
  return self:adjust_widget_ratio(...)
end

--- Add some widgets to the given fixed layout.
--
-- @method add
-- @tparam widget ... Widgets that should be added (must at least be one)
-- @noreturn
-- @emits widget::added All new widgets are passed in the parameters.
-- @emitstparam widget::added widget self The layout.
function ratio:add(...)
  -- No table.pack in Lua 5.1 :-(
  local args = { n=select('#', ...), ... }
  assert(args.n > 0, "need at least one widget to add")
  for i=1, args.n do
    local w = base.make_widget_from_value(args[i])
    base.check_widget(w)
    table.insert(self._private.widgets, w)
  end

  normalize(self)
  self:emit_signal("widget::layout_changed")
  self:emit_signal("widget::added", ...)
end

--- Remove a widget from the layout.
--
-- @method remove
-- @tparam number index The widget index to remove
-- @treturn boolean index If the operation is successful
-- @emits widget::removed
-- @emitstparam widget::removed widget self The fixed layout.
-- @emitstparam widget::removed widget widget index The removed widget.
-- @emitstparam widget::removed number index The removed index.
function ratio:remove(index)
  if not index or not self._private.widgets[index] then return false end

  local w = self._private.widgets[index]

  table.remove(self._private.ratios, index)
  table.remove(self._private.widgets, index)

  normalize(self)

  self:emit_signal("widget::layout_changed")
  self:emit_signal("widget::removed", w, index)

  return true
end

--- Insert a new widget in the layout at position `index`.
--
-- @method insert
-- @tparam number index The position.
-- @tparam widget widget The widget.
-- @treturn boolean `true` if the widget was inserted and `false` if the index
--  is invalid.
-- @emits widget::inserted
-- @emitstparam widget::inserted widget self The ratio layout.
-- @emitstparam widget::inserted widget widget index The inserted widget.
-- @emitstparam widget::inserted number count The widget count.
function ratio:insert(index, widget)
  if not index or index < 1 or index > #self._private.widgets + 1 then return false end

  base.check_widget(widget)

  table.insert(self._private.widgets, index, widget)

  normalize(self)

  self:emit_signal("widget::layout_changed")
  self:emit_signal("widget::inserted", widget, #self._private.widgets)

  return true
end

--- Set how the space of invisible or `0x0` sized widget is redistributed.
--
--@DOC_wibox_layout_ratio_strategy_EXAMPLE@
--
-- @property inner_fill_strategy
-- @tparam[opt="default"] string inner_fill_strategy One of the value listed above.
-- @propertyvalue "default" Honor the ratio and do not redistribute the space.
-- @propertyvalue "justify" Distribute the space among remaining widgets.
-- @propertyvalue "center" Squash remaining widgets and leave equal space on both side.
-- @propertyvalue "inner_spacing" Add equal spacing between all widgets.
-- @propertyvalue "spacing" Add equal spacing between all widgets and on the outside.
-- @propertyvalue "left" Squash remaining widgets and leave empty space on the left.
-- @propertyvalue "right" Squash remaining widgets and leave empty space on the right.
-- @propemits true false

function ratio:get_inner_fill_strategy()
  return self._private.inner_fill_strategy or "default"
end

local valid_strategies = {
  default     = true,
  justify     = true,
  center    = true,
  inner_spacing = true,
  spacing     = true,
  left      = true,
  right     = true
}

function ratio:set_inner_fill_strategy(strategy)
  assert(valid_strategies[strategy] ~= nil, "Invalid strategy: "..(strategy or ""))

  self._private.inner_fill_strategy = strategy
  self:emit_signal("widget::layout_changed")
  self:emit_signal("property::inner_fill_strategy", strategy)
end

local function get_layout(dir, widget1, ...)
  local ret = flex[dir](widget1, ...)

  gtable.crush(ret, ratio, true)

  ret._private.fill_space = nil

  ret._private.ratios = {}

  return ret
end

--- Returns a new horizontal ratio layout. A ratio layout shares the available space.
-- equally among all widgets. Widgets can be added via :add(widget).
-- @constructorfct wibox.layout.ratio.horizontal
-- @tparam widget ... Widgets that should be added to the layout.
function ratio.horizontal(...)
  return get_layout("horizontal", ...)
end

--- Returns a new vertical ratio layout. A ratio layout shares the available space.
-- equally among all widgets. Widgets can be added via :add(widget).
-- @constructorfct wibox.layout.ratio.vertical
-- @tparam widget ... Widgets that should be added to the layout.
function ratio.vertical(...)
  return get_layout("vertical", ...)
end

--@DOC_fixed_COMMON@

return ratio
