//----------------------------------------------------------------------
// Includes
//----------------------------------------------------------------------
#include "MantidAPI/HistoryView.h"
#include <iterator>
#include <algorithm>

namespace Mantid {
namespace API {

HistoryView::HistoryView(const WorkspaceHistory &wsHist)
    : m_wsHist(wsHist), m_historyItems() {
  // add all of the top level algorithms to the view by default
  const auto algorithms = wsHist.getAlgorithmHistories();
  m_historyItems =
      std::vector<HistoryItem>(algorithms.begin(), algorithms.end());
}

/**
 * Unroll an algorithm history to export its child algorithms.
 *
 * This places each of the child algorithm histories into the
 * HistoryView object. The parent is retained as a marker so we can
 * "roll" the history back up if we want. This method does nothing if
 * the history object has no children
 *
 * @param index :: index of the history object to unroll
 * @throws std::out_of_range if the index is larger than the number of history
 *items.
 */
void HistoryView::unroll(size_t index) {
  if (index >= m_historyItems.size()) {
    throw std::out_of_range("HistoryView::unroll() - Index out of range");
  }

  // advance to the item at the index
  auto it = m_historyItems.begin();
  std::advance(it, index);
  unroll(it);
}

#if defined(__GNUC__) && !defined(__clang__)
#define GCC_VERSION                                                            \
  (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__)
#endif

/**
 * Unroll an algorithm history to export its child algorithms.
 *
 * This places each of the child algorithm histories into the
 * HistoryView object. The parent is retained as a marker so we can
 * "roll" the history back up if we want. This method does nothing if
 * the history object has no children
 *
 * @param it :: iterator to the list of history item objects at the position to
 *unroll
 */
void HistoryView::unroll(std::vector<HistoryItem>::iterator &it) {
  const auto history = it->getAlgorithmHistory();
  const auto childHistories = history->getChildHistories();

  if (!it->isUnrolled() && !childHistories.empty()) {
    // mark this record as being ignored by the script builder
    it->unrolled(true);

    // insert each of the records, in order, at this position
    std::vector<HistoryItem> tmpHistory;
    tmpHistory.reserve(childHistories.size());
    for (const auto &item : childHistories) {
      tmpHistory.emplace_back(item);
    }
// since we are using a std::vector, do all insertions at the same time.
#if !defined(GCC_VERSION) || GCC_VERSION >= 409000
    ++it; // move iterator forward to insertion position
    it = m_historyItems.insert(it, tmpHistory.begin(), tmpHistory.end());
#else
    // workaround for GCC < 4.9
    // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55817
    ++it;
    for (auto itItem = tmpHistory.rbegin(); itItem != tmpHistory.rend();
         ++itItem) {
      it = m_historyItems.insert(it, *itItem);
    }
#endif
  } else
    ++it;
}

/**
 * Unroll the entire algorithm history.
 *
 * This is method will unroll the entire history for every algorithm by calling
 *unroll
 * on each element in the list. Every child algorithm with be visible after
 *calling this method.
 */
void HistoryView::unrollAll() {
  auto it = m_historyItems.begin();
  while (it != m_historyItems.end()) {
    // iterator passed by reference to prevent iterator invalidation.
    // iterator incremented within function.
    unroll(it);
  }
}

/**
 * Roll the entire algorithm history back up.
 *
 * This is method will roll up the entire history for every algorithm by calling
 *roll
 * on each element in the list. Only top level algorithms with be visible after
 *calling this method.
 */
void HistoryView::rollAll() {
  auto it = m_historyItems.begin();
  while (it != m_historyItems.end()) {
    // iterator incremented within function.
    roll(it);
  }
}

/**
 * Roll an unrolled algorithm history item and remove its children from the
 *view.
 *
 * This removes each of the child algorithm histories (if any) and marks
 * the parent as being "rolled up". Note that this will recursively "roll up"
 *any child
 * history objects that are also unrolled. This method does nothing if
 * the history object has no children.
 *
 * @param index :: index of the history object to unroll
 * @throws std::out_of_range if the index is larger than the number of history
 *items.
 */
void HistoryView::roll(size_t index) {
  if (index >= m_historyItems.size()) {
    throw std::out_of_range("HistoryView::roll() - Index out of range");
  }

  // advance to the item at the index
  auto it = m_historyItems.begin();
  std::advance(it, index);
  roll(it);
}

/**
 * Check if our children are unrolled and if so roll them back up.
 *
 * @param it :: iterator pointing to the item whose children will be rolled up.
 */
void HistoryView::rollChildren(std::vector<HistoryItem>::iterator it) {
  const size_t numChildren = it->numberOfChildren();
  ++it;
  for (size_t i = 0; i < numChildren; ++i) {
    if (it->isUnrolled())
      roll(it);
  }
}

/**
 * Roll an unrolled algorithm history item and remove its children from the
 *view.
 *
 * This removes each of the child algorithm histories (if any) and marks
 * the parent as being "rolled up". Note that this will recursively "roll up"
 *any child
 * history objects that are also unrolled. This method does nothing if
 * the history object has no children.
 *
 * @param it :: iterator to the list of history item objects at the positon to
 *roll
 */
void HistoryView::roll(std::vector<HistoryItem>::iterator &it) {

  // the number of records after this position
  const size_t numChildren = it->numberOfChildren();
  if (it->isUnrolled() && numChildren > 0) {
    // mark this record as not being ignored by the script builder
    it->unrolled(false);
    this->rollChildren(it);
    // Then just remove the children from the list
    ++it;
    it = m_historyItems.erase(it, it + numChildren);
  } else
    ++it;
}

/**
 * Filter the list of history items to remove any anlgorithms whos start
 * time is outside of the given range.
 *
 * @param start Start of time range
 * @param end End of time range
 */
void HistoryView::filterBetweenExecDate(Mantid::Kernel::DateAndTime start,
                                        Mantid::Kernel::DateAndTime end) {
  auto lastItem = std::remove_if(
      m_historyItems.begin(), m_historyItems.end(),
      [&start, &end](const HistoryItem &item) {
        Mantid::Kernel::DateAndTime algExecutionDate =
            item.getAlgorithmHistory()->executionDate();
        return algExecutionDate < start || algExecutionDate > end;
      });
  m_historyItems.erase(lastItem, m_historyItems.end());
}

} // namespace API
} // namespace Mantid