local MAX_NAME_LENGTH = 30
local MAX_WEAR = 65535
local SAME_TOOL_REPAIR_BOOST = math.ceil(MAX_WEAR * 0.12) -- 12%
local MATERIAL_TOOL_REPAIR_BOOST = {
   math.ceil(MAX_WEAR * 0.34), -- 25%
   math.ceil(MAX_WEAR * 0.68), -- 50%
   math.ceil(MAX_WEAR * 1), -- 75%
   MAX_WEAR, -- 100%
}
local NAME_COLOR = "#FFFF4C"

local function get_anvil_formspec(set_name)
   if not set_name then
      set_name = ""
   end
   return    "size[8,8.5]"..
   "background[1,1;1,1;gui_formbg2.png;true]"..
   "bgcolor[#080808BB;true]"..
   "list[current_player;main;0,4.5;8,4]"..
   "list[context;input;1,2.5;1,1;]"..
   "list[context;input;3.5,2.5;1,1;1]"..
   "list[context;output;6,2.5;1,1;]"..
   "image[2.35,2.6;0.8,0.8;plus.png]" ..
   "image[4.75,2.5;1,1;arrow0.png]" ..
   "image[2.6,0.65;3,1;rep.png]" ..
   "image[5.3,0.5;1.3,1.3;ham.png]" ..
   "image[1.3,0.5;1.3,1.3;pick.png]" ..
   "bgcolor[#080808BB;true]" ..
   default.gui_slots..
   "field_close_on_enter[name;false]"..
   "listring[context;input]"..
   "listring[context;output]"..
   "listring[current_player;main]"..
   "listring[current_player;main]"
end

-- Given a tool and material stack, returns how many items of the material stack
-- needs to be used up to repair the tool.
local function get_consumed_materials(tool, material)
   local wear = tool:get_wear()
   if wear == 0 then
      return 0
   end
   local health = (MAX_WEAR - wear)
   local matsize = material:get_count()
   local materials_used = 0
   for m=1, math.min(4, matsize) do
      materials_used = materials_used + 1
      if (wear - MATERIAL_TOOL_REPAIR_BOOST[m]) <= 0 then
         break
      end
   end
   return materials_used
end

-- Given 2 input stacks, tells you which is the tool and which is the material.
-- Returns ("tool", input1, input2) if input1 is tool and input2 is material.
-- Returns ("material", input2, input1) if input1 is material and input2 is tool.
-- Returns nil otherwise.
local function distinguish_tool_and_material(input1, input2)
   local def1 = input1:get_definition()
   local def2 = input2:get_definition()
   if def1.type == "tool" and def1._repair_material then
      return "tool", input1, input2
   elseif def2.type == "tool" and def2._repair_material then
      return "material", input2, input1
   else
      return nil
   end
end

-- Update the inventory slots of an anvil node.
-- meta: Metadata of anvil node
local function update_anvil_slots(meta)
   local inv = meta:get_inventory()
   local new_name = meta:get_string("set_name")
   local input1, input2, output
   input1 = inv:get_stack("input", 1)
   input2 = inv:get_stack("input", 2)
   output = inv:get_stack("output", 1)
   local new_output, name_item
   local just_rename = false

   -- Both input slots occupied
   if (not input1:is_empty() and not input2:is_empty()) then
      -- Repair, if tool
      local def1 = input1:get_definition()
      local def2 = input2:get_definition()

      -- Repair calculation helper.
      -- Adds the “inverse” values of wear1 and wear2.
      -- Then adds a boost health value directly.
      -- Returns the resulting (capped) wear.
      local function calculate_repair(wear1, wear2, boost)
         local new_health = (MAX_WEAR - wear1) + (MAX_WEAR - wear2)
         if boost then
            new_health = new_health + boost
         end
         return math.max(0, math.min(MAX_WEAR, MAX_WEAR - new_health))
      end

      -- Same tool twice
      if input1:get_name() == input2:get_name() and def1.type == "tool" and (input1:get_wear() > 0 or input2:get_wear() > 0) then
         -- Add tool health together plus a small bonus
         -- TODO: Combine tool enchantments
         local new_wear = calculate_repair(input1:get_wear(), input2:get_wear(), SAME_TOOL_REPAIR_BOOST)
         input1:set_wear(new_wear)
         name_item = input1
         new_output = name_item
      -- Tool + repair item
      else
         -- Any tool can have a repair item. This may be defined in the tool's item definition
         -- as an itemstring in the field `_repair_material`. Only if this field is set, the
         -- tool can be repaired with a material item.
         -- Example: Steel Pickaxe + Steel Ingot. `_repair_material = default:steel_ingot`

         -- Big repair bonus
         -- TODO: Combine tool enchantments
         local distinguished, tool, material = distinguish_tool_and_material(input1, input2)
         if distinguished then
            local tooldef = tool:get_definition()
            local has_correct_material = false
            if string.sub(tooldef._repair_material, 1, 6) == "group:" then
               has_correct_material = minetest.get_item_group(material:get_name(), string.sub(tooldef._repair_material, 7)) ~= 0
            elseif material:get_name() == tooldef._repair_material then
               has_correct_material = true
            end
            if has_correct_material and tool:get_wear() > 0 then
               local materials_used = get_consumed_materials(tool, material)
               local new_wear = calculate_repair(tool:get_wear(), MAX_WEAR, MATERIAL_TOOL_REPAIR_BOOST[materials_used])
               tool:set_wear(new_wear)
               name_item = tool
               new_output = name_item
            else
               new_output = ""
            end
         else
            new_output = ""
         end
      end
   -- Exactly 1 input slot occupied
   elseif (not input1:is_empty() and input2:is_empty()) or (input1:is_empty() and not input2:is_empty()) then
      -- Just rename item
      if input1:is_empty() then
         name_item = input2
      else
         name_item = input1
      end
      just_rename = true
   else
      new_output = ""
   end

   -- Rename handling
   if name_item then
      -- No renaming allowed with group no_rename=1
      if minetest.get_item_group(name_item:get_name(), "no_rename") == 1 then
         new_output = ""
      else
         if new_name == nil then
            new_name = ""
         end
         local meta = name_item:get_meta()
         local old_name = meta:get_string("name")
         -- Limit name length
         new_name = string.sub(new_name, 1, MAX_NAME_LENGTH)
         -- Don't rename if names are identical
         if new_name ~= old_name then
            -- Rename item
            if new_name == "" then
               -- Empty name
               if name_item:get_definition()._generate_description then
                  -- _generate_description(itemstack): If defined, set custom item description of itemstack.
                  name_item:get_definition()._generate_description(name_item)
               else
                  -- Otherwise, just clear description
                  meta:set_string("description", "")
               end
            else
               -- Custom name set. Colorize it!
               -- This makes the name visually different from unnamed items
               meta:set_string("description", core.colorize(NAME_COLOR, new_name))
            end
            -- Save the raw name internally, too
            meta:set_string("name", new_name)
            new_output = name_item
         elseif just_rename then
            new_output = ""
         end
      end
   end

   -- Set the new output slot
   if new_output ~= nil then
      inv:set_stack("output", 1, new_output)
   end
end

-- Drop input items of anvil at pos with metadata meta
local function drop_anvil_items(pos, meta)
   local inv = meta:get_inventory()
   for i=1, inv:get_size("input") do
      local stack = inv:get_stack("input", i)
      if not stack:is_empty() then
         local p = {x=pos.x+math.random(0, 10)/10-0.5, y=pos.y, z=pos.z+math.random(0, 10)/10-0.5}
         minetest.add_item(p, stack)
      end
   end
end

local anvildef = {
   groups = {cracky = 1},
   tiles = {'stations_anvil.png'},
   use_texture_alpha = 'opaque',
   paramtype = "light",
   sunlight_propagates = true,
   is_ground_content = false,
   paramtype2 = "facedir",
   drawtype = "mesh",
   mesh = 'anvils_anvil.obj',
   sounds = default.node_sound_metal_defaults(),
   after_place_node = function(pos, placer)
      local name = placer:get_player_name()
      local pinv = placer:get_inventory()
      local meta =  minetest.get_meta(pos);
      local owner = placer:get_player_name() or "";
      local privs = minetest.get_player_privs(owner);
      meta:set_string("owner",owner);
      meta:set_string("infotext","Anvil (owned by " .. owner .. "): ");
   end,
   after_dig_node = function(pos, oldnode, oldmetadata, digger)
      local meta = minetest.get_meta(pos)
      local meta2 = meta
      meta:from_table(oldmetadata)
      drop_anvil_items(pos, meta)
      meta:from_table(meta2:to_table())
   end,
   allow_metadata_inventory_put = function(pos, listname, index, stack, player)
      local meta = minetest.get_meta(pos);
      local privs = minetest.get_player_privs(player:get_player_name());
      if meta:get_string("owner")~=player:get_player_name() and not privs.privs then return 0 end
      if listname == "output" then
         return 0
      else
         return stack:get_count()
      end
   end,
   allow_metadata_inventory_move = function(pos, from_list, from_index, to_list, to_index, count, player)
      local meta = minetest.get_meta(pos);
      local privs = minetest.get_player_privs(player:get_player_name());
      if meta:get_string("owner")~=player:get_player_name() and not privs.privs then return 0 end
      if to_list == "output" then
         return 0
      elseif from_list == "output" and to_list == "input" then
         local meta = minetest.get_meta(pos)
         local inv = meta:get_inventory()
         if inv:get_stack(to_list, to_index):is_empty() then
            return count
         else
            return 0
         end
      else
         return count
      end
   end,
   on_metadata_inventory_put = function(pos, listname, index, stack, player)
      local meta = minetest.get_meta(pos)
      update_anvil_slots(meta)
   end,
   on_metadata_inventory_move = function(pos, from_list, from_index, to_list, to_index, count, player)
      local meta = minetest.get_meta(pos)
      if from_list == "output" and to_list == "input" then
         local inv = meta:get_inventory()
         for i=1, inv:get_size("input") do
            if i ~= to_index then
               local istack = inv:get_stack("input", i)
               istack:set_count(math.max(0, istack:get_count() - count))
               inv:set_stack("input", i, istack)
            end
         end
      end
      update_anvil_slots(meta)
   end,
   allow_metadata_inventory_take = function(pos, listname, index, stack, player)
      local meta = minetest.get_meta(pos);
      local privs = minetest.get_player_privs(player:get_player_name());
      if meta:get_string("owner")~=player:get_player_name() and not privs.privs then return 0 end
      return stack:get_count();
   end,
   on_metadata_inventory_take = function(pos, listname, index, stack, player)
      local meta = minetest.get_meta(pos)
      if listname == "output" then
         local inv = meta:get_inventory()
         local input1 = inv:get_stack("input", 1)
         local input2 = inv:get_stack("input", 2)
         -- Both slots occupied?
         if not input1:is_empty() and not input2:is_empty() then
            -- Take as many items as needed
            local distinguished, tool, material = distinguish_tool_and_material(input1, input2)
            if distinguished then
               -- Tool + material: Take tool and as many materials as needed
               local materials_used = get_consumed_materials(tool, material)
               material:set_count(material:get_count() - materials_used)
               tool:take_item()
               local player_name = player:get_player_name()
               minetest.sound_play("anvil_use", {to_player=player_name, gain = 1.0})
               if distinguished == "tool" then
                  input1, input2 = tool, material
               else
                  input1, input2 = material, tool
               end
               inv:set_stack("input", 1, input1)
               inv:set_stack("input", 2, input2)
            else
               -- Else take 1 item from each stack
               input1:take_item()
               input2:take_item()
               inv:set_stack("input", 1, input1)
               inv:set_stack("input", 2, input2)
            end
         else
            -- Otherwise: Rename mode. Remove the same amount of items from input
            -- as has been taken from output
            if not input1:is_empty() then
               input1:set_count(math.max(0, input1:get_count() - stack:get_count()))
               inv:set_stack("input", 1, input1)
            end
            if not input2:is_empty() then
               input2:set_count(math.max(0, input2:get_count() - stack:get_count()))
               inv:set_stack("input", 2, input2)
            end
         end
      elseif listname == "input" then
         update_anvil_slots(meta)
      end
   end,
   on_construct = function(pos)
      local meta = minetest.get_meta(pos)
      local inv = meta:get_inventory()
      inv:set_size("input", 2)
      inv:set_size("output", 1)
      local form = get_anvil_formspec()
      meta:set_string("formspec", form)
   end,
   on_receive_fields = function(pos, formname, fields, sender)
      if fields.name_button or fields.name then
         local set_name
         if fields.name == nil then
            set_name = ""
         else
            set_name = fields.name
         end
         local meta = minetest.get_meta(pos)
         -- Limit name length
         set_name = string.sub(set_name, 1, MAX_NAME_LENGTH)
         meta:set_string("set_name", set_name)
         update_anvil_slots(meta)
         meta:set_string("formspec", get_anvil_formspec(set_name))
      end
   end,
}
if minetest.get_modpath("screwdriver") then
   anvildef.on_rotate = screwdriver.rotate_simple
end

local anvildef0 = table.copy(anvildef)
anvildef0.description = "Anvil"
anvildef0._doc_items_longdesc =
[[The anvil allows you to repair tools and armor, and to give names to items.]]
anvildef0._doc_items_usagehelp =
"To use an anvil, rightclick it. An anvil has 2 input slots (on the left) and one output slot.\n"..
"To rename items, put an item stack in one of the item slots while keeping the other input slot empty. Type in a name, hit enter or “Set Name”, then take the renamed item from the output slot.\n"..
"There are two possibilities to repair tools (and armor):\n"..
"• Tool + Tool: Place two tools of the same type in the input slots. The “health” of the repaired tool is the sum of the “health” of both input tools, plus a 12% bonus.\n"..
"• Tool + Material: Some tools can also be repaired by combining them with an item that it's made of. For example, iron pickaxes can be repaired with iron ingots. This repairs the tool by 25%.\n"..
"Armor counts as a tool. It is possible to repair and rename a tool in a single step."


minetest.register_node("anvils:anvil", anvildef0)

minetest.register_craft({
   output = "anvils:anvil",
   recipe = {
      { "default:steelblock", "default:steelblock", "default:steelblock" },
      { "", "default:steel_ingot", "" },
      { "default:steel_ingot", "default:steel_ingot", "default:steel_ingot" },
   }
})
