local util = require("scripts.util")

--- @class EntityPrototypeAndQualityName
--- @field entity LuaEntityPrototype
--- @field quality string

---@param index uint
---@return LuaItemStack?
local function get_cursor_stack(index)
  local player = game.get_player(index) --[[@as LuaPlayer]]
  local cursor = player.cursor_stack
  if not (cursor and cursor.valid_for_read) then
    return
  end
  return cursor
end

---@param event EventData.CustomInputEvent
---@return EntityPrototypeAndQualityName?
local function get_selected_id(event)
  local selected = event.selected_prototype
  if not selected then
    return
  end

  if selected.base_type == "entity" then
    --- @cast selected.quality -?
    local player = game.get_player(event.player_index) --[[@as LuaPlayer]]
    local selected_entity = player.selected
    if not selected_entity then
      return { entity = prototypes.entity[selected.name], quality = selected.quality }
    end
    if selected_entity.type == "entity-ghost" and selected_entity.ghost_prototype.type ~= "tile" then
      return {
        entity = selected_entity.ghost_prototype --[[@as LuaEntityPrototype]],
        quality = selected.quality,
      }
    end
    return { entity = selected_entity.prototype, quality = selected.quality }

    -- _CodeGreen: I couldn't find anything in game where I could click on an item or recipe that actually had a CustomInputEvent fire
    -- But the code to handle them is here, I guess
  elseif selected.base_type == "item" then
    --- @cast selected.quality -?
    local item = prototypes.item[selected.name]
    local place_result = item.place_result
    if not place_result then
      return
    end
    return { entity = place_result, quality = selected.quality }
  elseif selected.base_type == "recipe" then
    --- @cast selected.quality -?
    --- @type LuaRecipePrototype
    local recipe = prototypes.recipe[selected.name]
    local main_product = recipe.main_product
    local products = main_product and { main_product } or recipe.products
    local item_prototypes = prototypes.item
    for _, product in pairs(products) do
      if product.type ~= "item" then
        goto continue
      end
      --- @cast product ItemProduct
      --- @type LuaItemPrototype
      local item = item_prototypes[product.name]
      local place_result = item.place_result
      if place_result then
        return { entity = place_result, quality = selected.quality }
      end
      ::continue::
    end
  end
end

---@param cursor LuaItemStack
---@param from string
--- @param quality string?
---@param to string?
---@return LocalisedString?
local function add_upgrade_filter(cursor, from, quality, to)
  if not to then
    return "message.bpt-entity-cannot-upgrade"
  end

  local first_index
  for i = 1, cursor.mapper_count do
    local mapper = cursor.get_mapper(i, "from")
    if not mapper then
      first_index = first_index or i
      goto continue
    end

    if mapper.type == "entity" and mapper.name == from and mapper.quality == quality then
      local to_mapper = cursor.get_mapper(i, "to")
      if to_mapper and to_mapper.name == to and to_mapper.quality == quality then
        return "message.bpt-filter-already-present"
      end
      cursor.set_mapper(i, "to", { type = "entity", name = to, quality = quality, comparator = quality and "=" or nil })
      return
    end

    ::continue::
  end

  if not first_index then
    first_index = cursor.mapper_count + 1
  end
  cursor.set_mapper(
    first_index,
    "from",
    { type = "entity", name = from, quality = quality, comparator = quality and "=" or nil }
  )
  cursor.set_mapper(
    first_index,
    "to",
    { type = "entity", name = to, quality = quality, comparator = quality and "=" or nil }
  )
end

---@param cursor LuaItemStack
---@param id EntityPrototypeAndQualityName
---@return LocalisedString?
local function add_filter(cursor, id)
  if cursor.is_deconstruction_item then
    local first_empty = 0
    local filters = cursor.entity_filters
    for i = 1, cursor.entity_filter_count do
      local filter = filters[i]
      if filter and filter.name == id.entity.name and filter.quality == id.quality then
        return "message.bpt-filter-already-present"
      elseif not filter and first_empty == 0 then
        first_empty = i
      end
    end
    if first_empty == 0 then
      first_empty = cursor.entity_filter_count + 1
    end
    --- @diagnostic disable-next-line: param-type-mismatch
    if not cursor.set_entity_filter(first_empty, { name = id.entity, quality = id.quality }) then
      return "message.bpt-unable-to-add-filter"
    end
  elseif cursor.is_upgrade_item then
    local next_upgrade = id.entity.next_upgrade
    local to = next_upgrade and next_upgrade.name or storage.downgrades[id.entity.name]
    return add_upgrade_filter(cursor, id.entity.name, id.quality, to)
  end
end

--- @param event EventData.CustomInputEvent
script.on_event("bpt-pipette-add", function(event)
  local cursor = get_cursor_stack(event.player_index)
  if not cursor then
    return
  end
  local entity_and_quality = get_selected_id(event)
  if not entity_and_quality then
    return
  end

  local player = game.get_player(event.player_index) --[[@as LuaPlayer]]
  local message = add_filter(cursor, entity_and_quality)
  if message then
    util.cursor_notification(player, { message }, "utility/cannot_build")
  else
    player.play_sound({ path = "utility/smart_pipette" })
  end
end)

---@param cursor LuaItemStack
---@param id EntityPrototypeAndQualityName
---@return LocalisedString?
local function remove_filter(cursor, id)
  if cursor.is_deconstruction_item then
    local filters = cursor.entity_filters
    for i = 1, cursor.entity_filter_count do
      local filter = filters[i]
      if filter and filter.name == id.entity.name and filter.quality == id.quality then
        cursor.set_entity_filter(i, nil)
        return
      end
    end
  elseif cursor.is_upgrade_item then
    for i = 1, cursor.mapper_count do
      local mapper = cursor.get_mapper(i, "from")
      --- @cast mapper -?
      if mapper.type == "entity" and mapper.name == id.entity.name and mapper.quality == id.quality then
        cursor.set_mapper(i, "from", nil)
        cursor.set_mapper(i, "to", nil)
        return
      end
    end
  end

  return "message.bpt-filter-not-present"
end

--- @param event EventData.CustomInputEvent
script.on_event("bpt-pipette-remove", function(event)
  local cursor = get_cursor_stack(event.player_index)
  if not cursor then
    return
  end
  local id = get_selected_id(event)
  if not id then
    return
  end

  local player = game.get_player(event.player_index) --[[@as LuaPlayer]]
  local message = remove_filter(cursor, id)
  if message then
    util.cursor_notification(player, { message }, "utility/cannot_build")
  else
    player.play_sound({ path = "utility/clear_cursor" })
  end
end)

--- @param event EventData.CustomInputEvent
script.on_event("bpt-pipette-downgrade", function(event)
  local cursor = get_cursor_stack(event.player_index)
  if not cursor then
    return
  end
  if not cursor.is_upgrade_item then
    return
  end

  local id = get_selected_id(event)
  if not id then
    return
  end

  local downgrade = storage.downgrades[id.entity.name]
  local next_upgrade = id.entity.next_upgrade
  local to = downgrade or (next_upgrade and next_upgrade.name)

  local player = game.get_player(event.player_index) --[[@as LuaPlayer]]
  local message = add_upgrade_filter(cursor, id.entity.name, id.quality, to)
  if message then
    if message == "message.bpt-entity-cannot-upgrade" then
      message = "message.bpt-entity-cannot-downgrade"
    end
    util.cursor_notification(player, { message }, "utility/cannot_build")
  else
    player.play_sound({ path = "utility/smart_pipette" })
  end
end)

local lib = {}

function lib.cache_downgrades()
  ---@type table<string, string>
  local downgrades = {}
  storage.downgrades = downgrades

  for name, entity in pairs(prototypes.entity) do
    --- @cast name string
    --- @cast entity LuaEntityPrototype
    local next_upgrade = entity.next_upgrade
    if next_upgrade then
      downgrades[next_upgrade.name] = name
    end
  end
end

return lib