-- Hearts view used in game screen and in the savegames selection screen.

local hearts = {}

function hearts:new(game)
  local object = {}
  setmetatable(object, self)
  self.__index = self

  object:initialize(game)

  return object
end

function hearts:initialize(game)

  self.game = game
  self.surface = sol.surface.create(90, 18)
  self.dst_x = 0
  self.dst_y = 0
  self.empty_heart_sprite = sol.sprite.create("hud/empty_heart")
  self.nb_max_hearts_displayed = game:get_max_life() / 4
  self.nb_current_hearts_displayed = game:get_life()
  self.all_hearts_img = sol.surface.load("sprites/hud/hearts.png")
end

function hearts:on_started()

  -- This function is called when the HUD starts or
  -- was disabled and gets enabled again.
  -- Unlike other HUD elements, the timers were canceled because they
  -- are attached to the menu and not to the game
  -- (this is because the hearts are also used in the savegame menu).
  self.danger_sound_timer = nil
  self:check()
  self:rebuild_surface()
end

-- Checks whether the view displays the correct info
-- and updates it if necessary.
function hearts:check()

  local need_rebuild = false

  -- Maximum life.
  local nb_max_hearts = self.game:get_max_life() / 4
  if nb_max_hearts ~= self.nb_max_hearts_displayed then
    need_rebuild = true

    if nb_max_hearts < self.nb_max_hearts_displayed then
      -- Decrease immediately if the max life is reduced.
      self.nb_current_hearts_displayed = self.game:get_life()
    end

    self.nb_max_hearts_displayed = nb_max_hearts
  end

  -- Current life.
  local nb_current_hearts = self.game:get_life()
  if nb_current_hearts ~= self.nb_current_hearts_displayed then

    need_rebuild = true
    if nb_current_hearts < self.nb_current_hearts_displayed then
      self.nb_current_hearts_displayed = self.nb_current_hearts_displayed - 1
    else
      self.nb_current_hearts_displayed = self.nb_current_hearts_displayed + 1
      if self.game:is_started()
          and self.nb_current_hearts_displayed % 4 == 0 then
        sol.audio.play_sound("heart")
      end
    end
  end

  -- If we are in-game, play an animation and a sound if the life is low.
  if self.game:is_started() then

    if self.game:get_life() <= self.game:get_max_life() / 4
        and not self.game:is_suspended() then
      need_rebuild = true
      if self.empty_heart_sprite:get_animation() ~= "danger" then
        self.empty_heart_sprite:set_animation("danger")
      end
      if self.danger_sound_timer == nil then
        self.danger_sound_timer = sol.timer.start(self, 250, function()
          self:repeat_danger_sound()
        end)
        self.danger_sound_timer:set_suspended_with_map(true)
      end
    elseif self.empty_heart_sprite:get_animation() ~= "normal" then
      need_rebuild = true
      self.empty_heart_sprite:set_animation("normal")
    end
  end

  -- Redraw the surface only if something has changed.
  if need_rebuild then
    self:rebuild_surface()
  end

  -- Schedule the next check.
  sol.timer.start(self, 50, function()
    self:check()
  end)
end

function hearts:repeat_danger_sound()

  if self.game:get_life() <= self.game:get_max_life() / 4 then

    sol.audio.play_sound("danger")
    self.danger_sound_timer = sol.timer.start(self, 750, function()
      self:repeat_danger_sound()
    end)
    self.danger_sound_timer:set_suspended_with_map(true)
  else
    self.danger_sound_timer = nil
  end
end

function hearts:rebuild_surface()

  self.surface:clear()

  -- Display the hearts.
  for i = 0, self.nb_max_hearts_displayed - 1 do
    local x, y = (i % 10) * 9, math.floor(i / 10) * 9
    self.empty_heart_sprite:draw(self.surface, x, y)
    if i < math.floor(self.nb_current_hearts_displayed / 4) then
      -- This heart is full.
      self.all_hearts_img:draw_region(27, 0, 9, 9, self.surface, x, y)
    end
  end

  -- Last fraction of heart.
  local i = math.floor(self.nb_current_hearts_displayed / 4)
  local remaining_fraction = self.nb_current_hearts_displayed % 4
  if remaining_fraction ~= 0 then
    local x, y = (i % 10) * 9, math.floor(i / 10) * 9
    self.all_hearts_img:draw_region((remaining_fraction - 1) * 9, 0, 9, 9, self.surface, x, y)
  end
end

function hearts:set_dst_position(x, y)
  self.dst_x = x
  self.dst_y = y
end

function hearts:on_draw(dst_surface)
  local x, y = self.dst_x, self.dst_y
  local width, height = dst_surface:get_size()
  if x < 0 then
    x = width + x
  end
  if y < 0 then
    y = height + y
  end

  -- Everything was already drawn on self.surface.
  self.surface:draw(dst_surface, x, y)
end

return hearts