-- Inventory-related methods
local Inventory = {}

-- TODO: Consider the Cursor Inventory too (otherwise items can be lost during transition)
-- TODO: Consider Filters (otherwise they are lost during transition)

-- Extracts a Player Cursor's Blueprint as a string (if present)
function Inventory.GetCursorBlueprintString(player)
    local blueprint = nil
    if player.is_cursor_blueprint() then
        if player.character
                and player.character.cursor_stack
                and player.character.cursor_stack.valid
                and player.character.cursor_stack.valid_for_read
        then
            blueprint = player.character.cursor_stack.export_stack()
        elseif player.cursor_stack
                and player.cursor_stack.valid
                and player.cursor_stack.valid_for_read
        then
            blueprint = player.cursor_stack.export_stack()
        else
            player.print("There was a Blueprint in your cursor, but Factorio incorrectly describes it as invalid. This is most likely because it's currently in the Blueprint Library (a known bug in Factorio).")
        end
    end
    return blueprint
end

-- Whether a Player's Cursor can non-destructively be replaced
function Inventory.WasCursorSafelyCleared(player)
    if not player or not player.cursor_stack.valid then
        return false
    end
    if player.is_cursor_empty() then return true end
    if player.is_cursor_blueprint() then return true end

    --[[ TODO:
    This doesn't usually happen, since the "source location" of the item
    seems to be lost after swapping the character.
    ]]
    if not player.cursor_stack_temporary then
        player.clear_cursor()
        return true
    end

    return false
end

-- Whether a Player's Inventory is vulnerable to going missing due to lack of a body
function Inventory.ShouldPersist(controller)
    return controller ~= defines.controllers.character
end

-- Ensure a Player's Inventory isn't full
function Inventory.Prune(player)
    local inventory = player.get_main_inventory()
    if not inventory then
        return
    end

    if inventory.count_empty_stacks() == 0 then
        player.print("Your inventory is almost full. Please throw some items away.")
        player.surface.spill_item_stack(player.position, inventory[#inventory])
        inventory[#inventory].clear()
    end
end

-- Persist one Inventory into another mod-created one
function Inventory.Persist(from, to)
    if not from then
        return nil
    end
    if not to then
        to = game.create_inventory(#from)
    else
        to.resize(#from)
    end
    for i = 1, #from do
        to[i].set_stack(from[i])
    end
    return to
end

-- Restore one Inventory into another
function Inventory.Restore(from, to)
    if not from or not to then
        return
    end
    local transition = math.min(#from, #to)
    for i = 1, transition do
        to[i].set_stack(from[i])
    end
    if transition < #to then
        for i = transition + 1, #to do
            to[i].set_stack()
        end
    end
end

return Inventory