-- Actions code for Advanced NPC by Zorman2000
---------------------------------------------------------------------------------------
-- Action functionality
---------------------------------------------------------------------------------------
-- The NPCs will be able to perform five fundamental actions that will allow
-- for them to perform any other kind of interaction in the world. These
-- fundamental actions are: place a node, dig a node, put items on an inventory,
-- take items from an inventory, find a node closeby (radius 3) and
-- walk a step on specific direction. These actions will be set on an action queue. 
-- The queue will have the specific steps, in order, for the NPC to be able to do 
-- something (example, go to a specific place and put a chest there). The 
-- fundamental actions are added to the action queue to make a complete task for the NPC.

npc.actions = {}

-- Describes actions with doors or openable nodes
npc.actions.const = {
  doors = {
    action = {
      OPEN = 1,
      CLOSE = 2
    },
    state = {
      OPEN = 1,
      CLOSED = 2
    }
  },
  beds = {
    LAY = 1,
    GET_UP = 2
  },
  sittable = {
    SIT = 1,
    GET_UP = 2
  }
}

npc.actions.one_nps_speed = 0.98
npc.actions.one_half_nps_speed = 1.40
npc.actions.two_nps_speed = 1.90

---------------------------------------------------------------------------------------
-- Actions
---------------------------------------------------------------------------------------
-- The following action alters the timer interval for executing actions, therefore
-- making waits and pauses possible, or increase timing when some actions want to
-- be performed faster, like walking.
function npc.actions.set_interval(self, args)
  local self_actions = args.self_actions
  local new_interval = args.interval
  local freeze_mobs_api = args.freeze

  self.actions.action_interval = new_interval
  return not freeze_mobs_api
end

-- The following action is for allowing the rest of mobs redo API to be executed
-- after this action ends. This is useful for times when no action is needed
-- and the NPC is allowed to roam freely.
function npc.actions.freeze(self, args)
  local freeze_mobs_api = args.freeze
  minetest.log("Received: "..dump(freeze_mobs_api))
  minetest.log("Returning: "..dump(not(freeze_mobs_api)))
  return not(freeze_mobs_api)
end

-- This action is to rotate to mob to a specifc direction. Currently, the code
-- contains also for diagonals, but remaining in the orthogonal domain is preferrable.
function npc.actions.rotate(self, args)
  local dir = args.dir
  local yaw = 0
  self.rotate = 0
  if dir == npc.direction.north then
    yaw = 0
  elseif dir == npc.direction.north_east then
    yaw = (7 * math.pi) / 4
  elseif dir == npc.direction.east then
    yaw = (3 * math.pi) / 2
  elseif dir == npc.direction.south_east then
    yaw = (5 * math.pi) / 4
  elseif dir == npc.direction.south then
    yaw = math.pi
  elseif dir == npc.direction.south_west then
    yaw = (3 * math.pi) / 4
  elseif dir == npc.direction.west then
    yaw = math.pi / 2
  elseif dir == npc.direction.north_west then
    yaw = math.pi / 4
  end
  self.object:setyaw(yaw)
end

-- This function will make the NPC walk one step on a 
-- specifc direction. One step means one node. It returns 
-- true if it can move on that direction, and false if there is an obstacle
function npc.actions.walk_step(self, args)
  local dir = args.dir
  local speed = args.speed
  local vel = {}
  -- Set default node per seconds
  if speed == nil then
    speed = npc.actions.one_nps_speed
  end
  if dir == npc.direction.north then
    vel = {x=0, y=0, z=speed}
  elseif dir == npc.direction.east then
    vel = {x=speed, y=0, z=0}
  elseif dir == npc.direction.south then
    vel = {x=0, y=0, z=-speed}
  elseif dir == npc.direction.west then
    vel = {x=-speed, y=0, z=0}
  end
  -- Rotate NPC
  npc.actions.rotate(self, {dir=dir})
  -- Set velocity so that NPC walks
  self.object:setvelocity(vel)
  -- Set walk animation
  self.object:set_animation({
      x = npc.ANIMATION_WALK_START,
      y = npc.ANIMATION_WALK_END},
      self.animation.speed_normal, 0)
end

-- This action makes the NPC stand and remain like that
function npc.actions.stand(self, args)
  local pos = args.pos
  local dir = args.dir
  -- Stop NPC
  self.object:setvelocity({x=0, y=0, z=0})
  -- If position given, set to that position
  if pos ~= nil then
    self.object:moveto(pos)
  end
    -- If dir given, set to that dir
  if dir ~= nil then
    npc.actions.rotate(self, {dir=dir})
  end
  -- Set stand animation
  self.object:set_animation({
        x = npc.ANIMATION_STAND_START,
        y = npc.ANIMATION_STAND_END},
        self.animation.speed_normal, 0)
end

-- This action makes the NPC sit on the node where it is
function npc.actions.sit(self, args)
  local pos = args.pos 
  local dir = args.dir
  -- Stop NPC
  self.object:setvelocity({x=0, y=0, z=0})
  -- If position given, set to that position
  if pos ~= nil then
    self.object:moveto(pos)
  end
  -- If dir given, set to that dir
  if dir ~= nil then
    npc.actions.rotate(self, {dir=dir})
  end
  -- Set sit animation
  self.object:set_animation({
        x = npc.ANIMATION_SIT_START,
        y = npc.ANIMATION_SIT_END},
        self.animation.speed_normal, 0)
end

-- This action makes the NPC lay on the node where it is
function npc.actions.lay(self, args)
  local pos = args.pos
  -- Stop NPC
  self.object:setvelocity({x=0, y=0, z=0})
  -- If position give, set to that position
  if pos ~= nil then
    self.object:moveto(pos)
  end
  -- Set sit animation
  self.object:set_animation({
        x = npc.ANIMATION_LAY_START,
        y = npc.ANIMATION_LAY_END},
        self.animation.speed_normal, 0)
end

-- Inventory functions for players and for nodes
-- This function is a convenience function to make it easy to put
-- and get items from another inventory (be it a player inv or 
-- a node inv)
function npc.actions.put_item_on_external_inventory(self, args)
  local player = args.player
  local pos = args.pos
  local inv_list = args.inv_list
  local item_name = args.item_name
  local count = args.count
  local is_furnace = args.is_furnace
  local inv
  if player ~= nil then
    inv = minetest.get_inventory({type="player", name=player})
  else
    inv = minetest.get_inventory({type="node", pos=pos})
  end

  -- Create ItemStack to put on external inventory
  local item = ItemStack(item_name.." "..count)
  -- Check if there is enough room to add the item on external invenotry
  if inv:room_for_item(inv_list, item) then
    -- Take item from NPC's inventory
    if npc.take_item_from_inventory_itemstring(self, item) then
      -- NPC doesn't have item and/or specified quantity
      return false
    end
    -- Add items to external inventory
    inv:add_item(inv_list, item)
    
    -- If this is a furnace, start furnace timer
    if is_furnace == true then
      minetest.get_node_timer(pos):start(1.0)
    end

    return true
  end
  -- Not able to put on external inventory
  return false
end

function npc.actions.take_item_from_external_inventory(self, args)
  local player = args.player
  local pos = args.pos
  local inv_list = args.inv_list
  local item_name = args.item_name
  local count = args.count
  local inv
  if player ~= nil then
    inv = minetest.get_inventory({type="player", name=player})
  else
    inv = minetest.get_inventory({type="node", pos=pos})
  end
  -- Create ItemSTack to take from external inventory
  local item = ItemStack(item_name.." "..count)
  -- Check if there is enough of the item to take
  if inv:contains_item(inv_list, item) then
    -- Add item to NPC's inventory
    npc.add_item_to_inventory_itemstring(self, item)
    -- Add items to external inventory
    inv:remove_item(inv_list, item)
    return true
  end
  -- Not able to put on external inventory
  return false
end

function npc.actions.check_external_inventory_contains_item(self, args)
  local player = args.player
  local pos = args.pos
  local inv_list = args.inv_list
  local item_name = args.item_name
  local count = args.count
  local inv
  if player ~= nil then
    inv = minetest.get_inventory({type="player", name=player})
  else
    inv = minetest.get_inventory({type="node", pos=pos})
  end

  -- Create ItemStack for checking the external inventory
  local item = ItemStack(item_name.." "..count)
  -- Check if inventory contains item
  return inv:contains_item(inv_list, item)
end

-- TODO: Refactor this function so that it uses a table to check
-- for doors instead of having separate logic for each door type
function npc.actions.get_openable_node_state(node, npc_dir)
  minetest.log("Node name: "..dump(node.name))
  local state = npc.actions.const.doors.state.CLOSED
  -- Check for default doors and gates
  local a_i1, a_i2 = string.find(node.name, "_a")
  -- Check for cottages gates
  local open_i1, open_i2 = string.find(node.name, "_close")
  -- Check for cottages half door
  local half_door_is_closed = false
  if node.name == "cottages:half_door" then
    half_door_is_closed = (node.param2 + 2) % 4 == npc_dir
  end
  if a_i1 == nil and open_i1 == nil and not half_door_is_closed then
    state = npc.actions.const.doors.state.OPEN
  end
  minetest.log("Door state: "..dump(state))
  return state
end

-- This function is used to open or close openable nodes.
-- Currently supported openable nodes are: any doors using the
-- default doors API, and the cottages mod gates and doors. 
function npc.actions.use_door(self, args)
  local pos = args.pos
  local action = args.action
  local dir = args.dir
  local node = minetest.get_node(pos)
  local state = npc.actions.get_openable_node_state(node, dir)

  local clicker = self.object
  if action ~= state then
    minetest.registered_nodes[node.name].on_rightclick(pos, node, clicker, nil, nil)
  end
end


---------------------------------------------------------------------------------------
-- Tasks functionality
---------------------------------------------------------------------------------------
-- Tasks are operations that require many actions to perform. Basic tasks, like
-- walking from one place to another, operating a furnace, storing or taking
-- items from a chest, are provided here.

-- This function allows a NPC to use a furnace using only items from
-- its own inventory. Fuel is not provided. Once the furnace is finished
-- with the fuel items the NPC will take whatever was cooked and whatever
-- remained to cook. The function received the position of the furnace
-- to use, and the item to cook in furnace. Item is an itemstring
function npc.actions.use_furnace(self, args)
  local pos = args.pos
  local item = args.item
  local freeze = args.freeze
  -- Define which items are usable as fuels. The NPC
  -- will mainly use this as fuels to avoid getting useful
  -- items (such as coal lumps) for burning
  local fuels = {"default:leaves", 
                 "default:pine_needles",
                 "default:tree",
                 "default:acacia_tree",
                 "default:aspen_tree",
                 "default:jungletree",
                 "default:pine_tree",
                 "default:coalblock",
                 "farming:straw"}

  -- Check if NPC has item to cook
  local src_item = npc.inventory_contains(self, npc.get_item_name(item))
  if src_item == nil then
    -- Unable to cook item that is not in inventory
    return false
  end

  -- Check if NPC has a fuel item
  for i = 1,9 do
    local fuel_item = npc.inventory_contains(self, fuels[i]) 
  
    if fuel_item ~= nil then
      -- Get fuel item's burn time
      local fuel_time = 
      minetest.get_craft_result({method="fuel", width=1, items={ItemStack(fuel_item.item_string)}}).time 
      local total_fuel_time = fuel_time * npc.get_item_count(fuel_item.item_string)
      minetest.log("Fuel time: "..dump(fuel_time))

      -- Get item to cook's cooking time
      local cook_result = 
      minetest.get_craft_result({method="cooking", width=1, items={ItemStack(src_item.item_string)}})
      local total_cook_time = cook_result.time * npc.get_item_count(item)
      minetest.log("Cook: "..dump(cook_result))

      minetest.log("Total cook time: "..total_cook_time
        ..", total fuel burn time: "..dump(total_fuel_time))

      -- Check if there is enough fuel to cook all items
      if total_cook_time > total_fuel_time then
        -- Don't have enough fuel to cook item. Return the difference
        -- so it may help on trying to acquire the fuel later.
        -- NOTE: Yes, returning here means that NPC could probably have other 
        -- items usable as fuels and ignore them. This should be ok for now,
        -- considering that fuel items are ordered in a way where cheaper, less
        -- useless items come first, saving possible valuable items.
        return cook_result.time - fuel_time
      end

      -- Calculate how much fuel is needed
      local fuel_amount = total_cook_time / fuel_time
      if fuel_amount < 1 then
        fuel_amount = 1
      end

      minetest.log("Amount of fuel needed: "..fuel_amount)

      -- Put this item on the fuel inventory list of the furnace
      local args = {
         player = nil, 
         pos = pos, 
         inv_list = "fuel",
         item_name = npc.get_item_name(fuel_item.item_string),
         count = fuel_amount
      }
      npc.add_action(self, npc.actions.put_item_on_external_inventory, args)
      -- Put the item that we want to cook on the furnace
      args = {
         player = nil, 
         pos = pos, 
         inv_list = "src",
         item_name = npc.get_item_name(src_item.item_string),
         count = npc.get_item_count(item),
         is_furnace = true
      }
      npc.add_action(self, npc.actions.put_item_on_external_inventory, args)

      -- Now, set NPC to wait until furnace is done.
      minetest.log("Setting wait action for "..dump(total_cook_time))
      npc.add_action(self, npc.actions.set_interval, {interval=total_cook_time, freeze=freeze})

      -- Reset timer
      npc.add_action(self, npc.actions.set_interval, {interval=1, freeze=true})

      -- If freeze is false, then we will have to find the way back to the furnace
      -- once cooking is done.
      if freeze == false then
        minetest.log("Adding walk to position to wandering: "..dump(pos))
        npc.add_task(self, npc.actions.walk_to_pos, {end_pos=pos, walkable={}})
      end

      -- Take cooked items back
      args = {
         
         player = nil, 
         pos = pos, 
         inv_list = "dst",
         item_name = cook_result.item:get_name(),
         count = npc.get_item_count(item),
         is_furnace = false
      }
      minetest.log("Taking item back: "..dump(pos))
      npc.add_action(self, npc.actions.take_item_from_external_inventory, args)

      minetest.log("Inventory: "..dump(self.inventory))

      return true
    end
  end
  -- Couldn't use the furnace due to lack of items
  return false
end

-- This function makes the NPC lay or stand up from a bed. The
-- pos is the location of the bed, action can be lay or get up
function npc.actions.use_bed(self, pos, action)
  local node = minetest.get_node(pos)
  minetest.log(dump(node))
  local dir = minetest.facedir_to_dir(node.param2)

  if action == npc.actions.const.beds.LAY then
    -- Get position
    local bed_pos = npc.actions.nodes.beds[node.name].get_lay_pos(pos, dir)
    -- Sit down on bed, rotate to correct direction
    npc.add_action(self, npc.actions.sit, {pos=bed_pos, dir=(node.param2 + 2) % 4})
    -- Lay down 
    npc.add_action(self, npc.actions.lay, {})
  else
    -- Calculate position to get up
    local bed_pos_y = npc.actions.nodes.beds[node.name].get_lay_pos(pos, dir).y
    local bed_pos = {x = pos.x, y = bed_pos_y, z = pos.z} 
    -- Sit up
    npc.add_action(self, npc.actions.sit, {pos=bed_pos})
    -- Initialize direction: Default is front of bottom of bed
    local dir = (node.param2 + 2) % 4
    -- Find empty node around node
    -- Take into account that mats are close to the floor, so y adjustmen is zero
    local y_adjustment = -1
    if npc.actions.nodes.beds[node.name].type == "mat" then
      y_adjustment = 0
    end
    local empty_nodes = npc.places.find_node_orthogonally(bed_pos, {"air", "cottages:bench"}, y_adjustment)
    if empty_nodes ~= nil then
      -- Get direction to the empty node
      dir = npc.actions.get_direction(bed_pos, empty_nodes[1].pos)
    end
    -- Calculate position to get out of bed
    local pos_out_of_bed =
      {x=empty_nodes[1].pos.x, y=empty_nodes[1].pos.y + 1, z=empty_nodes[1].pos.z}
    -- Account for benches if they are present to avoid standing over them
    if empty_nodes[1].name == "cottages:bench" then
      pos_out_of_bed = {x=empty_nodes[1].pos.x, y=empty_nodes[1].pos.y + 1, z=empty_nodes[1].pos.z}
      if empty_nodes[1].param2 == 0 then
        pos_out_of_bed.z = pos_out_of_bed.z - 0.3
      elseif empty_nodes[1].param2 == 1 then
        pos_out_of_bed.x = pos_out_of_bed.x - 0.3
      elseif empty_nodes[1].param2 == 2 then
        pos_out_of_bed.z = pos_out_of_bed.z + 0.3
      elseif empty_nodes[1].param2 == 3 then
        pos_out_of_bed.x = pos_out_of_bed.x + 0.3
      end
    end
    -- Stand out of bed
    npc.add_action(self, npc.actions.stand, {pos=pos_out_of_bed, dir=dir})
  end
end

-- This function makes the NPC lay or stand up from a bed. The
-- pos is the location of the bed, action can be lay or get up
function npc.actions.use_sittable(self, args)
  local pos = args.pos
  local action = args.action
  local node = minetest.get_node(pos)

  if action == npc.actions.const.sittable.SIT then
    -- Calculate position depending on bench
    minetest.log("Got sit position: "..dump(sit_pos))
    local sit_pos = npc.actions.nodes.sittable[node.name].get_sit_pos(pos, node.param2)
    -- Sit down on bench/chair/stairs
    npc.add_action(self, npc.actions.sit, {pos=sit_pos, dir=(node.param2 + 2) % 4})
  else
    -- Find empty areas around chair
    local dir = node.param2 + 2 % 4
    local empty_nodes = npc.places.find_node_orthogonally(pos, {"air"}, 0)
    if empty_nodes ~= nil then
      -- Get direction to the empty node
      dir = npc.actions.get_direction(pos, empty_nodes[1].pos)
    end
    -- Calculate position to get out of bed
    local pos_out_of_sittable =
      {x=empty_nodes[1].pos.x, y=empty_nodes[1].pos.y + 1, z=empty_nodes[1].pos.z}
    -- Stand
    npc.add_action(self, npc.actions.stand, {pos=pos_out_of_sittable, dir=dir})
  end
end

-- This function returns the direction enum
-- for the moving from v1 to v2
function npc.actions.get_direction(v1, v2)
  local dir = vector.subtract(v2, v1)
  if dir.x ~= 0 then
    if dir.x > 0 then
      return npc.direction.east
    else
      return npc.direction.west
    end
  elseif dir.z ~= 0 then
    if dir.z > 0 then
      return npc.direction.north
    else
      return npc.direction.south
    end
  end
end

-- This function can be used to make the NPC walk from one
-- position to another. If the optional parameter walkable_nodes
-- is included, which is a table of node names, these nodes are
-- going to be considered walkable for the algorithm to find a
-- path.
function npc.actions.walk_to_pos(self, args)
  -- Get arguments for this task 
  local end_pos = args.end_pos
  local walkable_nodes = args.walkable

  -- Round start_pos to make sure it can find start and end
  local start_pos = vector.round(self.object:getpos())
  -- Use y of end_pos (this can only be done assuming flat terrain)
  start_pos.y = self.object:getpos().y
  minetest.log("Walk to pos: Using start position: "..dump(start_pos))

  -- Set walkable nodes to empty if the parameter hasn't been used
  if walkable_nodes == nil then
    walkable_nodes = {}
  end

  -- Find path
  local path = pathfinder.find_path(start_pos, end_pos, 20, walkable_nodes)

  if path ~= nil then
    minetest.log("Found path to node: "..dump(end_pos))

    -- Local variables
    local door_opened = false
    local speed = npc.actions.two_nps_speed

    -- Set the action timer interval to half second. This is to account for
    -- the increased speed when walking.
    npc.add_action(self, npc.actions.set_interval, {interval=0.5, freeze=true})

    -- Add steps to path
    for i = 1, #path do
      -- Do not add an extra step if reached the goal node
      if (i+1) == #path then
        -- Add direction to last node
        local dir = npc.actions.get_direction(path[i].pos, end_pos)
        -- Add stand animation at end
        npc.add_action(self, npc.actions.stand, { dir = dir})
        break
      end
      -- Get direction to move from path[i] to path[i+1]
      local dir = npc.actions.get_direction(path[i].pos, path[i+1].pos)
      -- Check if next node is a door, if it is, open it, then walk
      if path[i+1].type == pathfinder.node_types.openable then
        -- Check if door is already open
        local node = minetest.get_node(path[i+1].pos)
        if npc.actions.get_openable_node_state(node, dir) == npc.actions.const.doors.state.CLOSED then
          minetest.log("Opening action to open door")
          -- Stop to open door, this avoids misplaced movements later on
          npc.add_action(self, npc.actions.stand, {dir=dir})
          -- Open door
          npc.add_action(self, npc.actions.use_door, {pos=path[i+1].pos, dir=dir, action=npc.actions.const.doors.action.OPEN})

          door_opened = true
        end
      end
      -- Add walk action to action queue
      npc.add_action(self, npc.actions.walk_step, {dir = dir, speed = speed})

      if door_opened then
          -- Stop to close door, this avoids misplaced movements later on
          local x_adj, z_adj = 0, 0
          if dir == 0 then
            z_adj = 0.1
          elseif dir == 1 then
            x_adj = 0.1
          elseif dir == 2 then
            z_adj = -0.1
          elseif dir == 3 then
            x_adj = -0.1
          end
          local pos_on_close = {x=path[i+1].pos.x + x_adj, y=path[i+1].pos.y + 1, z=path[i+1].pos.z + z_adj}
          npc.add_action(self, npc.actions.stand, {dir=(dir + 2)% 4, pos=pos_on_close})
          -- Close door
          npc.add_action(self, npc.actions.use_door, {pos=path[i+1].pos, action=npc.actions.const.doors.action.CLOSE})

          door_opened = false
      end

    end

    -- Return the action interval to default interval of 1 second
    -- By default, always freeze.
    npc.add_action(self, npc.actions.set_interval, {interval=1, freeze=true})

  else
    minetest.log("Unable to find path.")
  end
end