// Copyright (c) 2014-2019, The Monero Project
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// FIXME: move this into a full wallet2 unit test suite, if possible

#include "gtest/gtest.h"

#include "wallet/wallet2.h"
#include <string>

static tools::wallet2::transfer_container make_transfers_container(size_t N)
{
  tools::wallet2::transfer_container transfers;
  for (size_t n = 0; n < N; ++n)
  {
    transfers.push_back(AUTO_VAL_INIT(tools::wallet2::transfer_details()));
    tools::wallet2::transfer_details &td = transfers.back();
    td.m_block_height = 1000;
    td.m_spent = false;
    td.m_txid = crypto::null_hash;
    td.m_txid.data[0] = n & 0xff;
    td.m_txid.data[1] = (n >> 8) & 0xff;
    td.m_txid.data[2] = (n >> 16) & 0xff;
    td.m_txid.data[3] = (n >> 24) & 0xff;
  }
  return transfers;
}

#define SELECT(idx) \
  do { \
    auto i = std::find(unused_indices.begin(), unused_indices.end(), idx); \
    ASSERT_TRUE(i != unused_indices.end()); \
    unused_indices.erase(i); \
    selected.push_back(idx); \
  } while(0)

#define PICK(expected) \
  do { \
    size_t idx = w.pop_best_value_from(transfers, unused_indices, selected); \
    ASSERT_EQ(expected, idx); \
    selected.push_back(idx); \
  } while(0)

TEST(select_outputs, one_out_of_N)
{
  tools::wallet2 w;

  // check that if there are N-1 outputs of the same height, one of them
  // already selected, the next one selected is the one that's from a
  // different height
  tools::wallet2::transfer_container transfers = make_transfers_container(10);
  transfers[6].m_block_height = 700;
  std::vector<size_t> unused_indices({0, 1, 2, 3, 4, 5, 6, 7, 8, 9});
  std::vector<size_t> selected;
  SELECT(2);
  PICK(6);
}

TEST(select_outputs, order)
{
  tools::wallet2 w;

  // check that most unrelated heights are picked in order
  tools::wallet2::transfer_container transfers = make_transfers_container(5);
  transfers[0].m_block_height = 700;
  transfers[1].m_block_height = 700;
  transfers[2].m_block_height = 704;
  transfers[3].m_block_height = 716;
  transfers[4].m_block_height = 701;
  std::vector<size_t> unused_indices({0, 1, 2, 3, 4});
  std::vector<size_t> selected;
  SELECT(0);
  PICK(3); // first the one that's far away
  PICK(2); // then the one that's close
  PICK(4); // then the one that's adjacent
  PICK(1); // then the one that's on the same height
}