local Event = require "utils.event"
local Utils = require "utils.utils"

global.original_last_users_by_ent_pos = {}

Event.on_init(function()
  global.ag_surface=game.create_surface("antigrief",{autoplace_controls={coal={frequency="normal",richness="normal",size="none"},["copper-ore"]={frequency="normal",richness="normal",size="none"},["crude-oil"]={frequency="normal",richness="normal",size="none"},desert={frequency="normal",richness="normal",size="none"},dirt={frequency="normal",richness="normal",size="none"},["enemy-base"]={frequency="normal",richness="normal",size="none"},grass={frequency="normal",richness="normal",size="none"},["iron-ore"]={frequency="normal",richness="normal",size="none"},sand={frequency="normal",richness="normal",size="none"},stone={frequency="normal",richness="normal",size="none"},trees={frequency="normal",richness="normal",size="none"},["uranium-ore"]={frequency="normal",richness="normal",size="none"}},cliff_settings={cliff_elevation_0=1024,cliff_elevation_interval=10,name="cliff"},height=2000000,peaceful_mode=false,seed=3461559752,starting_area="very-low",starting_points={{x=0,y=0}},terrain_segmentation="normal",water="normal",width=2000000})
  global.ag_surface.always_day = true

end)

local function is_mocked(entity)
   return rawget(entity, 'mock')
end

local function place_entity_on_surface(entity, surface, replace, player)
  local new_entity = nil
  for _,e in ipairs(surface.find_entities_filtered{position = entity.position}) do
    if replace or e.type == "entity-ghost" then
      e.destroy()
    end
  end
  local entities_to_be_replaced = surface.find_entities_filtered{position = entity.position}
  if (replace or #entities_to_be_replaced == 0 or entities_to_be_replaced[1].type == entity.type) then
    new_entity = surface.create_entity{name = entity.name, position = entity.position, force = entity.force, direction = entity.direction}
    if new_entity then
      if not is_mocked(entity) then
        new_entity.copy_settings(entity)
      end
      if player then
        new_entity.last_user = player
      end
    end
  end
  return new_entity
end

Event.add(defines.events.on_chunk_generated, function(event)
   if event.surface.name == "antigrief" then
    local tiles = {}
    for x = event.area.left_top.x, event.area.right_bottom.x - 1 do
      for y = event.area.left_top.y, event.area.right_bottom.y - 1 do
        table.insert(tiles,{name="lab-dark-2", position = {x,y}})
      end
    end
    event.surface.set_tiles(tiles)
  end
end)

local function get_position_str(pos)
  return string.format("%d|%d", pos.x, pos.y)
end

local function on_entity_changed(event)  
  local entity = event.entity or event.destination
  local player = game.players[event.player_index]
  if player.admin or not entity.valid then return end --Freebees for admins
  if entity.last_user ~= player and entity.force == player.force then --commented out to be able to debug
    place_entity_on_surface(entity, global.ag_surface, true, event.player_index)
  end
  if entity.last_user then
    global.original_last_users_by_ent_pos[get_position_str(entity.position)] = entity.last_user.index
  end
end

Event.add(defines.events.on_robot_pre_mined, function(event)  
  --The bot isnt the culprit! The last user is! They marked it for deconstruction!
  if event.entity.valid and event.entity.last_user then
     event.player_index = event.entity.last_user.index
     on_entity_changed(event)
  end
end)

local function get_pre_rotate_direction(entity)
  --Some entities have 8 rotation steps and some have 4. So a mathmatical reverse is not possible
  entity.rotate{reverse=true}
  local direction = entity.direction
  entity.rotate()
  return direction
end

Event.add(defines.events.on_player_rotated_entity, function(event)  
  local entity = event.entity

  if not entity.valid then return end

  local ag_entities = global.ag_surface.find_entities_filtered{position = entity.position}
  --If a player has rotated twice we want to preserve the original state.
  if #ag_entities == 0 or not ag_entities[1].last_user or ag_entities[1].last_user ~= entity.last_user then

    --Mock entity us used because the api doesnt support pre_player_rotated entity.
    --The mocked entity has the entity state before rotation
    --We also dont know who rotated it and dont want the griefers name there so we set it to 1
    local mock_entity = {name = entity.name, position = entity.position, mock = true,
      last_user = game.players[1], force = entity.force, direction = get_pre_rotate_direction(entity)}
    event.entity = mock_entity
    on_entity_changed(event)
  end
end)
Event.add(defines.events.on_pre_entity_settings_pasted, on_entity_changed)

Event.add(defines.events.on_entity_died, function(event)  
  --is a player on the same force as the destroyed object
  if event.entity and event.entity.valid and event.entity.force.name == "player" and event.cause and
    event.cause.force == event.entity.force and event.cause.type == "player" then
    local new_entity = place_entity_on_surface(event.entity, global.ag_surface, true, event.cause.player)
    if new_entity and event.entity.type == "container" then
    local items = event.entity.get_inventory(defines.inventory.chest).get_contents()
      if items then
        for item, n in pairs(items) do
          new_entity.insert{name = item, count = n}
        end
      end
    end
  end
end)

Event.add(defines.events.on_player_mined_entity, on_entity_changed)

Event.add(defines.events.on_marked_for_deconstruction, function(event)
  if event.entity.last_user then 
    global.original_last_users_by_ent_pos[get_position_str(event.entity.position)] = event.entity.last_user.index
  end
end)


local Module = {}

Module.undo = function(player)
  if type(player) == "nil" or type(player) == "string" then return --No support for strings!
  elseif type(player) == "number" then player = game.players[player] end

  --Remove all items from all surfaces that player placed an entity on
  for _,surface in pairs(game.surfaces) do
    if surface ~= global.ag_surface then
      for _,e in ipairs(surface.find_entities_filtered{force = player.force.name}) do
        if e.last_user == player then
          e.destroy()
        end
      end
    end
  end

  for _,e in ipairs(global.ag_surface.find_entities_filtered{}) do
    if e.last_user == player then
      --Place removed entity IF no collision is detected
      local last_user = global.original_last_users_by_ent_pos[get_position_str(e.position)]
      local new_entity = place_entity_on_surface(e, game.surfaces.nauvis, false, last_user)
      --Transfer items
      if new_entity then

        local player = Utils.ternary(new_entity.last_user, new_entity.last_user, game.player)
        local event = {created_entity = new_entity, player_index = player.index, stack = {}}
        script.raise_event(defines.events.on_built_entity, event)

        if e.type == "container" then
          local items = e.get_inventory(defines.inventory.chest).get_contents()
          if items then
            for item, n in pairs(items) do
              new_entity.insert{name = item, count = n}
            end
          end
        end
        e.destroy() --destory entity only if a new entity was created
      end
    end
  end
end

Module.antigrief_surface_tp = function()
  if game.player then
    if game.player.surface == global.ag_surface then
      game.player.teleport(game.player.position, game.surfaces.nauvis)
    else
      game.player.teleport(game.player.position, global.ag_surface)
    end
  end
end

Module.count_removed_entities = function(player)
  return #Utils.find_entities_by_last_user(player, global.ag_surface)
end

return Module