local grouped = require("scripts.database.grouped")
local util = require("scripts.util")

--- @class History: {[integer]: GenericPrototype, index: integer}
local history = {}
local mt = { __index = history }
script.register_metatable("history", mt)

function history.new()
  return setmetatable({ index = 0 }, mt)
end

--- @param prototype GenericPrototype
--- @param grouping_mode GroupingMode
--- @return boolean
function history:push(prototype, grouping_mode)
  if grouping_mode ~= "none" then
    if
      (prototype.object_name == "LuaRecipePrototype" and grouping_mode == "all")
      or (prototype.object_name ~= "LuaRecipePrototype" and grouping_mode ~= "none")
    then
      local base = grouped.material[util.get_path(prototype)]
      if base then
        prototype = base
      end
    end
  end
  if self:current() == prototype then
    return false
  end
  for i = self.index + 1, #self do
    self[i] = nil
  end
  for i = self.index, 1, -1 do
    if self[i] == prototype then
      table.remove(self, i)
    end
  end
  self[#self + 1] = prototype
  self.index = #self
  return true
end

function history:prev()
  self.index = math.max(1, self.index - 1)
end

function history:next()
  self.index = math.min(#self, self.index + 1)
end

function history:current()
  return self[self.index]
end

function history:at_front()
  return self.index <= 1
end

function history:at_back()
  return self.index == #self
end

return history