defmodule ShardTest.MST do
  use ExUnit.Case
  alias SData.MerkleSearchTree, as: MST
  doctest Shard.Application

  test "merkle search tree 1" do
    y = Enum.reduce(0..1000, %MST{},
                    fn i, acc -> MST.insert(acc, i) end)


    z = Enum.reduce(Enum.shuffle(0..1000), %MST{},
                    fn i, acc -> MST.insert(acc, i) end)

    for i <- 0..1000 do
      assert MST.get(y, i) == true
      assert MST.get(z, i) == true
    end
    assert MST.get(y, 9999) == nil
    assert MST.get(z, -1001) == nil
    assert MST.get(z, 1.01) == nil

    IO.puts "y.root: #{y.root|>Base.encode16}"
    IO.puts "z.root: #{z.root|>Base.encode16}"
    assert y.root == z.root
  end

  test "merkle search tree 2" do
    items = for i <- 0..1000 do
              h = SData.term_hash i
              {h, SData.term_hash h}
            end

    merge = fn a, b -> if a > b do a else b end end

    y = Enum.reduce(items, %MST{merge: merge},
                    fn {k, v}, acc -> MST.insert(acc, k, v) end)

    z = Enum.reduce(Enum.shuffle(items), %MST{merge: merge},
                    fn {k, v}, acc -> MST.insert(acc, k, v) end)

    for {k, v} <- items do
      assert MST.get(y, k) == v
      assert MST.get(z, k) == v
    end

    IO.puts "y.root: #{y.root|>Base.encode16}"
    IO.puts "z.root: #{z.root|>Base.encode16}"
    assert y.root == z.root
  end

  test "merkle search tree 3" do
    merge = fn a, b -> if a > b do a else b end end

    y = Enum.reduce(0..1000, %MST{merge: merge},
                    fn i, acc -> MST.insert(acc, i, i) end)
    y = Enum.reduce(0..1000, y,
                    fn i, acc -> MST.insert(acc, i, i + 2 * rem(i, 2) - 1) end)


    z = Enum.reduce(Enum.shuffle(0..1000), %MST{merge: merge},
                    fn i, acc -> MST.insert(acc, i, i) end)
    z = Enum.reduce(Enum.shuffle(0..1000), z,
                    fn i, acc -> MST.insert(acc, i, i + 2 * rem(i, 2) - 1) end)

    for i <- 0..1000 do
      val = if rem(i, 2) == 1 do i+1 else i end
      assert MST.get(y, i) == val
      assert MST.get(z, i) == val
    end
    assert MST.get(y, 9999) == nil
    assert MST.get(z, -1001) == nil
    assert MST.get(z, 1.01) == nil

    IO.puts "y.root: #{y.root|>Base.encode16}"
    IO.puts "z.root: #{z.root|>Base.encode16}"
    assert y.root == z.root
  end

  test "merkle search tree 4" do
    items = for i <- 0..1000 do
              h = SData.term_hash i
              {h, SData.term_hash h}
            end

    cmp = fn {a1, b1}, {a2, b2} ->
            cond do
              a1 < a2 -> :before
              a1 > a2 -> :after
              b1 > b2 -> :before
              b1 < b2 -> :after
              true -> :duplicate
            end
          end

    y = Enum.reduce(items, %MST{cmp: cmp},
                    fn {a, b}, acc -> MST.insert(acc, {a, b}) end)

    z = Enum.reduce(Enum.shuffle(items), %MST{cmp: cmp},
                    fn {a, b}, acc -> MST.insert(acc, {a, b}) end)

    for {k, v} <- items do
      assert MST.get(y, {k, v}) == true
      assert MST.get(z, {k, v}) == true
    end
    assert MST.get(z, {"foo", "bar"}) == nil

    IO.puts "y.root: #{y.root|>Base.encode16}"
    IO.puts "z.root: #{z.root|>Base.encode16}"
    assert y.root == z.root

    MST.last(y, nil, 10)
  end

  test "merkle search tree 5: MST.last" do
    y = Enum.reduce(0..1000, %MST{},
                    fn i, acc -> MST.insert(acc, i) end)

    assert(MST.last(y, nil, 2) == [{999, true}, {1000, true}])
    assert(MST.last(y, 42, 2) == [{40, true}, {41, true}])

    stuff = for i <- 100..199, do: {i, true}
    assert MST.last(y, 200, 100) == stuff

    stuff = for i <- 200..299, do: {i, true}
    assert MST.last(y, 300, 100) == stuff

    stuff = for i <- 200..499, do: {i, true}
    assert MST.last(y, 500, 300) == stuff
  end

  test "merkle search tree 6: MST.merge" do
    y = Enum.reduce([1, 2, 42], %MST{}, fn i, acc -> MST.insert(acc, i) end)
    z = Enum.reduce([2, 12], %MST{}, fn i, acc -> MST.insert(acc, i) end)

    IO.puts "y: "
    MST.dump y
    IO.puts "z: "
    MST.dump z

    mg1 = MST.merge(y, z)
    IO.puts "mg1: "
    MST.dump mg1

    mg2 = MST.merge(y, z)
    IO.puts "mg2: "
    MST.dump mg2
    assert mg1.root == mg2.root
  end

  test "merkle search tree 7: MST.merge" do
    items1 = (for i <- 1..1000, do: i*2+40)
    items2 = (for i <- 1..1000, do: i*3)

    y = Enum.reduce(items1, %MST{}, fn i, acc -> MST.insert(acc, i) end)
    z = Enum.reduce(items2, %MST{}, fn i, acc -> MST.insert(acc, i) end)

    IO.puts "(merge) y.root: #{y.root|>Base.encode16}"
    IO.puts "(merge) z.root: #{z.root|>Base.encode16}"

    mg1 = MST.merge(y, z)
    IO.puts "(merge) mg1.root: #{mg1.root|>Base.encode16}"

    mg2 = MST.merge(y, z)
    IO.puts "(merge) mg2.root: #{mg2.root|>Base.encode16}"

    assert mg1.root == mg2.root

    items1t = (for i <- items1, do: {i, true})
    items2t = (for i <- items2, do: {i, true})
    assert MST.last(y, nil, 1000) == items1t
    assert MST.last(z, nil, 1000) == items2t

    all_items = (items1t ++ items2t) |> Enum.sort |> Enum.uniq
    assert MST.last(mg1, nil, 2000) == all_items
  end

  test "merkle search tree 8: MST.merge callback" do
    items1 = (for i <- 1..1000, do: i*2+40)
    items2 = (for i <- 1..1000, do: i*3)

    y = Enum.reduce(items1, %MST{}, fn i, acc -> MST.insert(acc, i) end)
    z = Enum.reduce(items2, %MST{}, fn i, acc -> MST.insert(acc, i) end)

    {:ok, cb_called} = Agent.start_link fn -> [] end

    cb = fn i, true -> Agent.update(cb_called, fn x -> [i | x] end) end
    mg = MST.merge(y, z, cb)

    cb_vals = Agent.get cb_called, &(&1)
    expected = MapSet.difference(MapSet.new(items2), MapSet.new(items1))
      |> MapSet.to_list
      |> Enum.sort
      |> Enum.reverse
    assert expected == cb_vals
  end

end