defmodule ElixirRtree do
  alias ElixirRtree.Node
  alias ElixirRtree.Utils
  require Logger
  import IO.ANSI
  @moduledoc false
  # Entre 1 y 64800. Bigger value => ^ updates speed, ~v query speed.
  @max_area 20000

  def new(opts) do
    {f,s} = :rand.seed(:exrop,opts[:seed])
    {node,new_ticket} = Node.new(f,s)

    tree_init = case opts[:type] do
      Map -> %{}
      MerkleMap -> %MerkleMap{}
    end

    tree = tree_init
           |> opts[:type].put(:ticket,new_ticket)
           |> opts[:type].put(:root,node)
           |> opts[:type].put(node,{[],nil,[{0,0},{0,0}]})

    {tree,%{params: opts, seeding: f}}
  end

  # Helpers

  def get_root(rbundle) do
    rbundle.tree |> rbundle[:type].get(:root)
  end

  def is_root?(rbundle,node) do
    get_root(rbundle) == node
  end

  # Actions

  def rinsert(rbundle,{id,_box} = leaf) do
    if rbundle.tree |> rbundle[:type].get(id) do
      if rbundle.verbose,do: Logger.debug(cyan() <>"["<>green()<>"Insertion"<>cyan()<>"] failed:" <> yellow() <> " [#{id}] " <> cyan() <> "already exists at tree." <> yellow() <> " [Tip]"<> cyan() <> " use " <> yellow() <>"update_leaf/3")
      rbundle.tree
    else
      path = best_subtree(rbundle,leaf)
      t1 = :os.system_time(:microsecond)
      r = insertion(rbundle,path,leaf)
      |> recursive_update(tl(path),leaf,:insertion)
      t2 = :os.system_time(:microsecond)
      if rbundle.verbose,do: Logger.debug(cyan() <>"["<>green()<>"Insertion"<>cyan()<>"] success: "<> yellow() <> "[#{id}]" <> cyan() <> " was inserted at" <> yellow() <>" ['#{hd(path)}']")
      if rbundle.verbose,do: Logger.info(cyan() <>"["<>green()<>"Insertion"<>cyan()<>"] took" <> yellow() <> " #{t2-t1} µs")
      r
    end
  end

  def bquery(rbundle,box) do
    t1 = :os.system_time(:microsecond)
    r = find_match_leafs(rbundle,box,[get_root(rbundle)],[],[])
    t2 = :os.system_time(:microsecond)
    if rbundle.verbose,do: Logger.info(cyan() <> "["<>color(201)<>"Query"<>cyan()<>"] box " <> yellow() <> "#{box |> Kernel.inspect} " <> cyan() <> "took " <> yellow() <> "#{t2-t1} µs")
    r
  end

  def bquery(rbundle,box,depth) do
    find_match_depth(rbundle,box,[{get_root(rbundle),0}],[],depth)
  end

  def rdelete(rbundle,id) do
    t1 = :os.system_time(:microsecond)
    r = if rbundle.tree |> rbundle[:type].get(id) do
      remove(rbundle,id)
    else
      rbundle.tree
    end
    t2 = :os.system_time(:microsecond)
    if rbundle.verbose,do: Logger.info(cyan() <>"["<>color(124)<>"Delete"<>cyan()<>"] leaf "<>yellow()<>"[#{id}]"<>cyan()<>" took "<>yellow()<>"#{t2-t1} µs")
    r
  end

  def rupdate_leaf(rbundle,id,{old_box,new_box} = boxes) do
    if rbundle.tree |> rbundle[:type].get(id) do
      t1 = :os.system_time(:microsecond)
      r = update(rbundle,id,boxes)
      t2 = :os.system_time(:microsecond)
      if rbundle.verbose,do: Logger.info(cyan()<>"["<>color(195)<>"Update"<>cyan()<>"] "<>yellow()<>"[#{id}]"<>cyan()<>" from "<>yellow()<>"#{old_box |> Kernel.inspect}"<>cyan()<>" to "<>yellow()<>"#{new_box |> Kernel.inspect}"<>cyan()<>" took "<>yellow()<>"#{t2-t1} µs")
      r
    else
      if rbundle.verbose,do: Logger.warn(cyan()<>"["<>color(195)<>"Update"<>cyan()<>"] "<>yellow()<>"[#{id}] doesn't exists"<>cyan())
      rbundle.tree
    end
  end

  # You dont need to know old_box but is a BIT slower
  def rupdate_leaf(rbundle,id,new_box) do
    rupdate_leaf(rbundle,id,{rbundle.tree |> rbundle[:type].get(id) |> Utils.tuple_value(:bbox),new_box})
  end

  # Internal actions
  ## Insert

  # triple - S (Structure Swifty Shift)
  def triple_s(rbundle,old_node,new_node,{id,box}) do
    tuple_entry = {old_node_childs_update,_daddy,_bbox} = rbundle.tree |> rbundle[:type].get(old_node) |> (fn {n,d,b} -> {n -- [id],d,b} end).()
    tree_update = rbundle.tree
                  |> rbundle[:type].update!(new_node, fn {ch,d,b} -> {[id] ++ ch,d,b} end)
                  |> rbundle[:type].update!(id,fn {ch,_d,b} -> {ch,new_node,b} end)

    if length(old_node_childs_update) > 0 do
      %{rbundle | tree: tree_update |> rbundle[:type].put(old_node,tuple_entry)} |> recursive_update(old_node,box,:deletion)
    else
      %{rbundle | tree: tree_update} |> remove(old_node)
    end
  end

  defp insertion(rbundle,branch,{_id,_box} = leaf) do

    tree_update = add_entry(rbundle,hd(branch),leaf)

    childs = tree_update |> rbundle[:type].get(hd(branch)) |> Utils.tuple_value(:childs)

    final_tree = if length(childs) > rbundle.width do
      handle_overflow(%{rbundle | tree: tree_update},branch)
    else
      tree_update
    end

    %{rbundle | tree: final_tree}
  end

  defp add_entry(rbundle,node,{id,box} = _leaf) do
    rbundle.tree
    |> rbundle[:type].update!(node,fn {ch,daddy,b} -> {[id] ++ ch,daddy,Utils.combine_multiple([box,b])} end)
    |> rbundle[:type].put(id,{:leaf,node,box})
  end

  defp handle_overflow(rbundle,branch) do
    n = hd(branch)
    {node_n,new_node} = split(rbundle,n)
    treeck = rbundle.tree |> rbundle[:type].put(:ticket,new_node.next_ticket)

    if is_root?(rbundle,n) do
      {new_root,ticket} = Node.new(rbundle.seeding,treeck |> rbundle[:type].get(:ticket))
      treeck = treeck |> rbundle[:type].put(:ticket,ticket)
      root_bbox = Utils.combine_multiple([node_n.bbox,new_node.bbox])
      treeck = treeck |> rbundle[:type].put(new_node.id,{new_node.childs,new_root,new_node.bbox})
      |> rbundle[:type].replace!(node_n.id,{node_n.childs,new_root,node_n.bbox})
      |> rbundle[:type].replace!(:root,new_root)
      |> rbundle[:type].put(new_root,{[node_n.id,new_node.id],nil,root_bbox})
      new_node.childs |> Enum.reduce(treeck,fn c,acc ->
        acc |> rbundle[:type].update!(c,fn {ch,_d,b} -> {ch,new_node.id,b} end)
      end)
    else
      parent = hd(tl(branch))
      treeck = treeck
       |> rbundle[:type].put(new_node.id,{new_node.childs,parent,new_node.bbox})
       |> rbundle[:type].replace!(node_n.id,{node_n.childs,parent,node_n.bbox})
       |> rbundle[:type].update!(parent,fn {ch,d,b} -> {[new_node.id] ++ ch,d,Utils.combine_multiple([b,new_node.bbox])} end)
      updated_tree = new_node.childs |> Enum.reduce(treeck,fn c,acc ->
        acc |> rbundle[:type].update!(c,fn {ch,_d,b} -> {ch,new_node.id,b} end)
      end)

      if length(updated_tree |> rbundle[:type].get(parent) |> elem(0)) > rbundle.width, do: handle_overflow(%{rbundle | tree: updated_tree},tl(branch)), else: updated_tree
    end
  end

  defp split(rbundle,node) do

    sorted_nodes = rbundle.tree
                   |> rbundle[:type].get(node)
                   |> Utils.tuple_value(:childs)
                   |> Enum.map(fn n ->
                        box = rbundle.tree |> rbundle[:type].get(n) |> Utils.tuple_value(:bbox)
                      {box |> Utils.middle_value,n,box}
                    end)
                   |> Enum.sort
                   |> Enum.map(fn {_x,y,z} -> {y,z} end)

    {n_id,n_bbox} = sorted_nodes
                    |> Enum.slice(0..((rbundle.width/2) - 1 |> Kernel.trunc)) |> Enum.unzip

    {dn_id,dn_bbox} = sorted_nodes
                      |> Enum.slice(((rbundle.width/2) |> Kernel.trunc)..length(sorted_nodes) - 1) |> Enum.unzip

    {new_node,next_ticket} = Node.new(rbundle.seeding,rbundle.tree |> rbundle[:type].get(:ticket))
    n_bounds = n_bbox |> Utils.combine_multiple
    dn_bounds = dn_bbox |> Utils.combine_multiple

    {%{id: node, childs: n_id, bbox: n_bounds},
      %{id: new_node, childs: dn_id, bbox: dn_bounds, next_ticket: next_ticket}}
  end

  defp best_subtree(rbundle,leaf) do
    find_best_subtree(rbundle,get_root(rbundle),leaf,[])
  end

  defp find_best_subtree(rbundle,root,{_id,box} = leaf,track) do
    childs = rbundle.tree |> rbundle[:type].get(root) |> Utils.tuple_value(:childs)

    if is_list(childs) and length(childs) > 0 do
      winner = get_best_candidate(rbundle,childs,box)
      new_track = [root] ++ track
      find_best_subtree(rbundle,winner,leaf,new_track)
    else
      if is_atom(childs), do: track, else: [root] ++ track
    end
  end

  defp get_best_candidate(rbundle,candidates,box) do
    win_entry = candidates |> Enum.reduce_while(%{id: :not_id,cost: :infinity},fn c,acc ->
      cbox = rbundle.tree |> rbundle[:type].get(c) |> Utils.tuple_value(:bbox)

      if Utils.contained?(cbox,box) do
        {:halt, %{id: c, cost: 0}}
      else
        enlargement = Utils.enlargement_area(cbox,box)
        if enlargement < acc |> Map.get(:cost) do
          {:cont, %{id: c, cost: enlargement}}
        else
          {:cont, acc}
        end
      end
    end)
    win_entry[:id]
  end

  ## Query

  defp find_match_leafs(rbundle,box,dig,leafs,flood) do
    f = hd(dig)
    tail = if length(dig) > 1, do: tl(dig), else: []
    {content,_dad,fbox} = rbundle.tree |> rbundle[:type].get(f)
    {new_dig,new_leafs,new_flood} = if Utils.overlap?(fbox,box) do
        if is_atom(content) do
          {tail,[f] ++ leafs,flood}
        else
          if Utils.contained?(box,fbox), do: {tail,leafs,[f] ++ flood}, else: {content ++ tail,leafs,flood}
        end
      else
        {tail,leafs,flood}
    end

    if length(new_dig) > 0 do
      find_match_leafs(rbundle,box,new_dig,new_leafs,new_flood)
    else
      new_leafs ++ explore_flood(rbundle,new_flood)
    end
  end

  defp explore_flood(rbundle,flood) do
    next_floor = flood |> Enum.flat_map(fn x ->
                                        case rbundle.tree |> rbundle[:type].get(x) |> Utils.tuple_value(:childs) do
                                          :leaf -> []
                                          any -> any
                                        end end)

    if length(next_floor) > 0,do: explore_flood(rbundle,next_floor), else: flood
  end

  defp find_match_depth(rbundle,box,dig,leafs,depth) do
    {f,cdepth} = hd(dig)
    tail = if length(dig) > 1, do: tl(dig), else: []
    {content,_dad,fbox} = rbundle.tree |> rbundle[:type].get(f)

    {new_dig,new_leafs} = if Utils.overlap?(fbox,box) do
      if cdepth < depth and is_list(content) do
        childs = content |> Enum.map(fn c -> {c,cdepth + 1} end)
        {childs ++ tail,leafs}
      else
        {tail, [f] ++ leafs}
      end
    else
      {tail,leafs}
    end

    if length(new_dig) > 0, do: find_match_depth(rbundle,box,new_dig,new_leafs,depth), else: new_leafs
  end

  ## Delete

  defp remove(rbundle,id) do
    {_ch,parent,removed_bbox} = rbundle.tree |> rbundle[:type].get(id)

    if parent do
      tree_updated = rbundle.tree
        |> rbundle[:type].delete(id)
        |> rbundle[:type].update!(parent,fn {ch,daddy,b} -> {ch -- [id],daddy,b} end)
      parent_childs = tree_updated |> rbundle[:type].get(parent) |> elem(0)
      if length(parent_childs) > 0 do
        %{rbundle | tree: tree_updated} |> recursive_update(parent,removed_bbox,:deletion)
      else
        remove(%{rbundle | tree: tree_updated},parent)
      end
    else
      rbundle.tree |> rbundle[:type].update!(id,fn {ch,daddy,_b} -> {ch,daddy,[{0,0},{0,0}]} end)
    end
  end

  ## Hard update

  defp update(rbundle,id,{old_box,new_box}) do

    parent = rbundle.tree |> rbundle[:type].get(id) |> Utils.tuple_value(:dad)
    parent_box = rbundle.tree |> rbundle[:type].get(parent) |> Utils.tuple_value(:bbox)

    updated_tree = rbundle.tree |> rbundle[:type].update!(id, fn {ch,d,_b} -> {ch,d,new_box} end)
    local_rbundle = %{rbundle | tree: updated_tree}

    if Utils.contained?(parent_box,new_box) do
      if Utils.in_border?(parent_box,old_box) do
        if rbundle.verbose,do: Logger.debug(cyan()<>"["<>color(195)<>"Update"<>cyan()<>"] Good case: new box "<>yellow()<>"(#{new_box |> Kernel.inspect})"<>cyan()<>" of "<>yellow()<>"[#{id}]"<>cyan()<>" reduce the parent "<>yellow()<>"(['#{parent}'])"<>cyan()<>" box")
        local_rbundle |> recursive_update(parent,old_box,:deletion)
      else
        if rbundle.verbose,do: Logger.debug(cyan()<>"["<>color(195)<>"Update"<>cyan()<>"] Best case: new box "<>yellow()<>"(#{new_box |> Kernel.inspect})"<>cyan()<>" of "<>yellow()<>"[#{id}]"<>cyan()<>" was contained by his parent "<>yellow()<>"(['#{parent}'])")
        local_rbundle.tree
      end
    else
      case local_rbundle |> node_brothers(parent) |> (fn b -> good_slot?(local_rbundle,b,new_box) end).() do
        {new_parent,_new_brothers,_new_parent_box} ->
          if rbundle.verbose,do: Logger.debug(cyan()<>"["<>color(195)<>"Update"<>cyan()<>"] Neutral case: new box "<>yellow()<>"(#{new_box |> Kernel.inspect})"<>cyan()<>" of "<>yellow()<>"[#{id}]"<>cyan()<>" increases the parent box but there is an available slot at one uncle "<>yellow()<>"(['#{new_parent}'])")
          triple_s(local_rbundle,parent,new_parent,{id,old_box})

        nil ->  if Utils.area(parent_box) >= @max_area do
                  if rbundle.verbose,do: Logger.debug(cyan()<>"["<>color(195)<>"Update"<>cyan()<>"] Worst case: new box "<>yellow()<>"(#{new_box |> Kernel.inspect})"<>cyan()<>" of "<>yellow()<>"[#{id}]"<>cyan()<>" increases the parent box which was so big "<>yellow()<>"#{(((Utils.area(parent_box) |> Kernel.trunc)/@max_area) * 100) |> Kernel.trunc } %. "<>cyan()<>"So we proceed to delete "<>yellow()<>"[#{id}]"<>cyan()<>" and reinsert at tree")
                  local_rbundle |> top_down({id,new_box})
                else
                  if rbundle.verbose,do: Logger.debug(cyan()<>"["<>color(195)<>"Update"<>cyan()<>"] Bad case: new box "<>yellow()<>"(#{new_box |> Kernel.inspect})"<>cyan()<>" of "<>yellow()<>"[#{id}]"<>cyan()<>" increases the parent box which isn't that big yet "<>yellow()<>"#{(((Utils.area(parent_box) |> Kernel.trunc)/@max_area) * 100) |> Kernel.trunc} %. "<>cyan()<>"So we proceed to increase parent "<>yellow()<>"(['#{parent}'])"<>cyan()<>" box")
                  local_rbundle |> recursive_update(parent,new_box,:insertion)
                end
      end
    end
  end

  ## Common updates

  defp top_down(rbundle,{id,box}) do
    %{rbundle | tree: rbundle |> remove(id)} |> rinsert({id,box})
  end

  # Recursive bbox updates when you have node path from root (at insertion)
  defp recursive_update(rbundle,path,{_id,box} = leaf,:insertion)when length(path) > 0 do
    {modified,t} = update_node_bbox(rbundle,hd(path),box,:insertion)

    if modified and length(path) > 1, do: recursive_update(%{rbundle | tree: t},tl(path),leaf,:insertion), else: rbundle.tree
  end

  # Recursive bbox updates when u dont have node path from root, so you have to query parents map... (at delete)
  defp recursive_update(rbundle,node,box,mode)when is_list(node) |> Kernel.not do
    {modified,t} = update_node_bbox(rbundle,node,box,mode)
    next = rbundle.tree |> rbundle[:type].get(node) |> Utils.tuple_value(:dad)
    if modified and next, do: recursive_update(%{rbundle | tree: t},next,box,mode), else: t
  end

  # Typical dumbass safe method
  defp recursive_update(rbundle,_path,_leaf,:insertion) do
    rbundle.tree
  end

  defp update_node_bbox(rbundle,node,the_box,action) do
    node_box = rbundle.tree |> rbundle[:type].get(node) |> Utils.tuple_value(:bbox)
    new_bbox = case action do
      :insertion -> Utils.combine(node_box,the_box)
      :deletion -> if Utils.in_border?(node_box,the_box) do
                      rbundle.tree
                      |> rbundle[:type].get(node)
                      |> Utils.tuple_value(:childs)
                      |> Enum.map(fn c ->
                        rbundle.tree |> rbundle[:type].get(c) |> Utils.tuple_value(:bbox) end)
                      |> Utils.combine_multiple
                    else
                      node_box
                    end
    end

    bbox_mutation(rbundle,node,new_bbox,node_box)
  end

  defp bbox_mutation(rbundle,node,new_bbox,node_box) do
    if new_bbox == node_box do
      {false,rbundle.tree}
    else
      t = rbundle.tree |> rbundle[:type].update!(node, fn {ch,d,_b} -> {ch,d,new_bbox} end)
      {true,t}
    end
  end

  # Return the brothers of the node [{brother_id, brother_childs, brother_box},...]
  defp node_brothers(rbundle,node) do
    parent = rbundle.tree |> rbundle[:type].get(node) |> Utils.tuple_value(:dad)
    rbundle.tree
    |> rbundle[:type].get(parent)
    |> Utils.tuple_value(:childs)
    |> (fn c -> if c, do: c -- [node], else: [] end).()
    |> Enum.map(fn b ->
      tuple = rbundle.tree |> rbundle[:type].get(b)
      {b,tuple |> Utils.tuple_value(:childs),tuple |> Utils.tuple_value(:bbox)} end)
  end

  # Find a good slot (at bros/brothers list) for the box, it means that the brother hasnt the max childs and the box is at the limits of his own
  defp good_slot?(rbundle,bros,box) do
    bros |> Enum.find(fn {_bid,bchilds,bbox} -> length(bchilds) < rbundle.width and Utils.contained?(bbox,box) end)
  end

end