/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "mozilla/AsyncEventDispatcher.h"
#include "mozilla/dom/Element.h"
#include "nsCOMPtr.h"
#include "nsTreeSelection.h"
#include "XULTreeElement.h"
#include "nsITreeView.h"
#include "nsString.h"
#include "nsIContent.h"
#include "nsNameSpaceManager.h"
#include "nsGkAtoms.h"
#include "nsComponentManagerUtils.h"
#include "nsTreeColumns.h"

using namespace mozilla;
using dom::XULTreeElement;

// A helper class for managing our ranges of selection.
struct nsTreeRange {
  nsTreeSelection* mSelection;

  nsTreeRange* mPrev;
  nsTreeRange* mNext;

  int32_t mMin;
  int32_t mMax;

  nsTreeRange(nsTreeSelection* aSel, int32_t aSingleVal)
      : mSelection(aSel),
        mPrev(nullptr),
        mNext(nullptr),
        mMin(aSingleVal),
        mMax(aSingleVal) {}
  nsTreeRange(nsTreeSelection* aSel, int32_t aMin, int32_t aMax)
      : mSelection(aSel),
        mPrev(nullptr),
        mNext(nullptr),
        mMin(aMin),
        mMax(aMax) {}

  ~nsTreeRange() { delete mNext; }

  void Connect(nsTreeRange* aPrev = nullptr, nsTreeRange* aNext = nullptr) {
    if (aPrev)
      aPrev->mNext = this;
    else
      mSelection->mFirstRange = this;

    if (aNext) aNext->mPrev = this;

    mPrev = aPrev;
    mNext = aNext;
  }

  nsresult RemoveRange(int32_t aStart, int32_t aEnd) {
    // This should so be a loop... sigh...
    // We start past the range to remove, so no more to remove
    if (aEnd < mMin) return NS_OK;
    // We are the last range to be affected
    if (aEnd < mMax) {
      if (aStart <= mMin) {
        // Just chop the start of the range off
        mMin = aEnd + 1;
      } else {
        // We need to split the range
        nsTreeRange* range = new nsTreeRange(mSelection, aEnd + 1, mMax);
        if (!range) return NS_ERROR_OUT_OF_MEMORY;

        mMax = aStart - 1;
        range->Connect(this, mNext);
      }
      return NS_OK;
    }
    nsTreeRange* next = mNext;
    if (aStart <= mMin) {
      // The remove includes us, remove ourselves from the list
      if (mPrev)
        mPrev->mNext = next;
      else
        mSelection->mFirstRange = next;

      if (next) next->mPrev = mPrev;
      mPrev = mNext = nullptr;
      delete this;
    } else if (aStart <= mMax) {
      // Just chop the end of the range off
      mMax = aStart - 1;
    }
    return next ? next->RemoveRange(aStart, aEnd) : NS_OK;
  }

  nsresult Remove(int32_t aIndex) {
    if (aIndex >= mMin && aIndex <= mMax) {
      // We have found the range that contains us.
      if (mMin == mMax) {
        // Delete the whole range.
        if (mPrev) mPrev->mNext = mNext;
        if (mNext) mNext->mPrev = mPrev;
        nsTreeRange* first = mSelection->mFirstRange;
        if (first == this) mSelection->mFirstRange = mNext;
        mNext = mPrev = nullptr;
        delete this;
      } else if (aIndex == mMin)
        mMin++;
      else if (aIndex == mMax)
        mMax--;
      else {
        // We have to break this range.
        nsTreeRange* newRange = new nsTreeRange(mSelection, aIndex + 1, mMax);
        if (!newRange) return NS_ERROR_OUT_OF_MEMORY;

        newRange->Connect(this, mNext);
        mMax = aIndex - 1;
      }
    } else if (mNext)
      return mNext->Remove(aIndex);

    return NS_OK;
  }

  nsresult Add(int32_t aIndex) {
    if (aIndex < mMin) {
      // We have found a spot to insert.
      if (aIndex + 1 == mMin)
        mMin = aIndex;
      else if (mPrev && mPrev->mMax + 1 == aIndex)
        mPrev->mMax = aIndex;
      else {
        // We have to create a new range.
        nsTreeRange* newRange = new nsTreeRange(mSelection, aIndex);
        if (!newRange) return NS_ERROR_OUT_OF_MEMORY;

        newRange->Connect(mPrev, this);
      }
    } else if (mNext)
      mNext->Add(aIndex);
    else {
      // Insert on to the end.
      if (mMax + 1 == aIndex)
        mMax = aIndex;
      else {
        // We have to create a new range.
        nsTreeRange* newRange = new nsTreeRange(mSelection, aIndex);
        if (!newRange) return NS_ERROR_OUT_OF_MEMORY;

        newRange->Connect(this, nullptr);
      }
    }
    return NS_OK;
  }

  bool Contains(int32_t aIndex) {
    if (aIndex >= mMin && aIndex <= mMax) return true;

    if (mNext) return mNext->Contains(aIndex);

    return false;
  }

  int32_t Count() {
    int32_t total = mMax - mMin + 1;
    if (mNext) total += mNext->Count();
    return total;
  }

  static void CollectRanges(nsTreeRange* aRange, nsTArray<int32_t>& aRanges) {
    nsTreeRange* cur = aRange;
    while (cur) {
      aRanges.AppendElement(cur->mMin);
      aRanges.AppendElement(cur->mMax);
      cur = cur->mNext;
    }
  }

  static void InvalidateRanges(XULTreeElement* aTree,
                               nsTArray<int32_t>& aRanges) {
    if (aTree) {
      RefPtr<nsXULElement> tree = aTree;
      for (uint32_t i = 0; i < aRanges.Length(); i += 2) {
        aTree->InvalidateRange(aRanges[i], aRanges[i + 1]);
      }
    }
  }

  void Invalidate() {
    nsTArray<int32_t> ranges;
    CollectRanges(this, ranges);
    InvalidateRanges(mSelection->mTree, ranges);
  }

  void RemoveAllBut(int32_t aIndex) {
    if (aIndex >= mMin && aIndex <= mMax) {
      // Invalidate everything in this list.
      nsTArray<int32_t> ranges;
      CollectRanges(mSelection->mFirstRange, ranges);

      mMin = aIndex;
      mMax = aIndex;

      nsTreeRange* first = mSelection->mFirstRange;
      if (mPrev) mPrev->mNext = mNext;
      if (mNext) mNext->mPrev = mPrev;
      mNext = mPrev = nullptr;

      if (first != this) {
        delete mSelection->mFirstRange;
        mSelection->mFirstRange = this;
      }
      InvalidateRanges(mSelection->mTree, ranges);
    } else if (mNext)
      mNext->RemoveAllBut(aIndex);
  }

  void Insert(nsTreeRange* aRange) {
    if (mMin >= aRange->mMax)
      aRange->Connect(mPrev, this);
    else if (mNext)
      mNext->Insert(aRange);
    else
      aRange->Connect(this, nullptr);
  }
};

nsTreeSelection::nsTreeSelection(XULTreeElement* aTree)
    : mTree(aTree),
      mSuppressed(false),
      mCurrentIndex(-1),
      mShiftSelectPivot(-1),
      mFirstRange(nullptr) {}

nsTreeSelection::~nsTreeSelection() {
  delete mFirstRange;
  if (mSelectTimer) mSelectTimer->Cancel();
}

NS_IMPL_CYCLE_COLLECTION(nsTreeSelection, mTree)

NS_IMPL_CYCLE_COLLECTING_ADDREF(nsTreeSelection)
NS_IMPL_CYCLE_COLLECTING_RELEASE(nsTreeSelection)

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsTreeSelection)
  NS_INTERFACE_MAP_ENTRY(nsITreeSelection)
  NS_INTERFACE_MAP_ENTRY(nsINativeTreeSelection)
  NS_INTERFACE_MAP_ENTRY(nsISupports)
NS_INTERFACE_MAP_END

NS_IMETHODIMP nsTreeSelection::GetTree(XULTreeElement** aTree) {
  NS_IF_ADDREF(*aTree = mTree);
  return NS_OK;
}

NS_IMETHODIMP nsTreeSelection::SetTree(XULTreeElement* aTree) {
  if (mSelectTimer) {
    mSelectTimer->Cancel();
    mSelectTimer = nullptr;
  }

  mTree = aTree;
  return NS_OK;
}

NS_IMETHODIMP nsTreeSelection::GetSingle(bool* aSingle) {
  if (!mTree) {
    return NS_ERROR_NULL_POINTER;
  }

  *aSingle = mTree->AttrValueIs(kNameSpaceID_None, nsGkAtoms::seltype,
                                u"single"_ns, eCaseMatters);

  return NS_OK;
}

NS_IMETHODIMP nsTreeSelection::IsSelected(int32_t aIndex, bool* aResult) {
  if (mFirstRange)
    *aResult = mFirstRange->Contains(aIndex);
  else
    *aResult = false;
  return NS_OK;
}

NS_IMETHODIMP nsTreeSelection::TimedSelect(int32_t aIndex, int32_t aMsec) {
  bool suppressSelect = mSuppressed;

  if (aMsec != -1) mSuppressed = true;

  nsresult rv = Select(aIndex);
  if (NS_FAILED(rv)) return rv;

  if (aMsec != -1) {
    mSuppressed = suppressSelect;
    if (!mSuppressed) {
      if (mSelectTimer) mSelectTimer->Cancel();

      if (!mTree) {
        return NS_ERROR_UNEXPECTED;
      }
      nsIEventTarget* target =
          mTree->OwnerDoc()->EventTargetFor(TaskCategory::Other);
      NS_NewTimerWithFuncCallback(getter_AddRefs(mSelectTimer), SelectCallback,
                                  this, aMsec, nsITimer::TYPE_ONE_SHOT,
                                  "nsTreeSelection::SelectCallback", target);
    }
  }

  return NS_OK;
}

NS_IMETHODIMP nsTreeSelection::Select(int32_t aIndex) {
  mShiftSelectPivot = -1;

  nsresult rv = SetCurrentIndex(aIndex);
  if (NS_FAILED(rv)) return rv;

  if (mFirstRange) {
    bool alreadySelected = mFirstRange->Contains(aIndex);

    if (alreadySelected) {
      int32_t count = mFirstRange->Count();
      if (count > 1) {
        // We need to deselect everything but our item.
        mFirstRange->RemoveAllBut(aIndex);
        FireOnSelectHandler();
      }
      return NS_OK;
    } else {
      // Clear out our selection.
      mFirstRange->Invalidate();
      delete mFirstRange;
    }
  }

  // Create our new selection.
  mFirstRange = new nsTreeRange(this, aIndex);
  if (!mFirstRange) return NS_ERROR_OUT_OF_MEMORY;

  mFirstRange->Invalidate();

  // Fire the select event
  FireOnSelectHandler();
  return NS_OK;
}

NS_IMETHODIMP nsTreeSelection::ToggleSelect(int32_t aIndex) {
  // There are six cases that can occur on a ToggleSelect with our
  // range code.
  // (1) A new range should be made for a selection.
  // (2) A single range is removed from the selection.
  // (3) The item is added to an existing range.
  // (4) The item is removed from an existing range.
  // (5) The addition of the item causes two ranges to be merged.
  // (6) The removal of the item causes two ranges to be split.
  mShiftSelectPivot = -1;
  nsresult rv = SetCurrentIndex(aIndex);
  if (NS_FAILED(rv)) return rv;

  if (!mFirstRange)
    Select(aIndex);
  else {
    if (!mFirstRange->Contains(aIndex)) {
      bool single;
      rv = GetSingle(&single);
      if (NS_SUCCEEDED(rv) && !single) rv = mFirstRange->Add(aIndex);
    } else
      rv = mFirstRange->Remove(aIndex);
    if (NS_SUCCEEDED(rv)) {
      if (mTree) mTree->InvalidateRow(aIndex);

      FireOnSelectHandler();
    }
  }

  return rv;
}

NS_IMETHODIMP nsTreeSelection::RangedSelect(int32_t aStartIndex,
                                            int32_t aEndIndex, bool aAugment) {
  bool single;
  nsresult rv = GetSingle(&single);
  if (NS_FAILED(rv)) return rv;

  if ((mFirstRange || (aStartIndex != aEndIndex)) && single) return NS_OK;

  if (!aAugment) {
    // Clear our selection.
    if (mFirstRange) {
      mFirstRange->Invalidate();
      delete mFirstRange;
      mFirstRange = nullptr;
    }
  }

  if (aStartIndex == -1) {
    if (mShiftSelectPivot != -1)
      aStartIndex = mShiftSelectPivot;
    else if (mCurrentIndex != -1)
      aStartIndex = mCurrentIndex;
    else
      aStartIndex = aEndIndex;
  }

  mShiftSelectPivot = aStartIndex;
  rv = SetCurrentIndex(aEndIndex);
  if (NS_FAILED(rv)) return rv;

  int32_t start = aStartIndex < aEndIndex ? aStartIndex : aEndIndex;
  int32_t end = aStartIndex < aEndIndex ? aEndIndex : aStartIndex;

  if (aAugment && mFirstRange) {
    // We need to remove all the items within our selected range from the
    // selection, and then we insert our new range into the list.
    nsresult rv = mFirstRange->RemoveRange(start, end);
    if (NS_FAILED(rv)) return rv;
  }

  nsTreeRange* range = new nsTreeRange(this, start, end);
  if (!range) return NS_ERROR_OUT_OF_MEMORY;

  range->Invalidate();

  if (aAugment && mFirstRange)
    mFirstRange->Insert(range);
  else
    mFirstRange = range;

  FireOnSelectHandler();

  return NS_OK;
}

NS_IMETHODIMP nsTreeSelection::ClearRange(int32_t aStartIndex,
                                          int32_t aEndIndex) {
  nsresult rv = SetCurrentIndex(aEndIndex);
  if (NS_FAILED(rv)) return rv;

  if (mFirstRange) {
    int32_t start = aStartIndex < aEndIndex ? aStartIndex : aEndIndex;
    int32_t end = aStartIndex < aEndIndex ? aEndIndex : aStartIndex;

    mFirstRange->RemoveRange(start, end);

    if (mTree) mTree->InvalidateRange(start, end);
  }

  return NS_OK;
}

NS_IMETHODIMP nsTreeSelection::ClearSelection() {
  if (mFirstRange) {
    mFirstRange->Invalidate();
    delete mFirstRange;
    mFirstRange = nullptr;
  }
  mShiftSelectPivot = -1;

  FireOnSelectHandler();

  return NS_OK;
}

NS_IMETHODIMP nsTreeSelection::SelectAll() {
  if (!mTree) return NS_OK;

  nsCOMPtr<nsITreeView> view = mTree->GetView();
  if (!view) return NS_OK;

  int32_t rowCount;
  view->GetRowCount(&rowCount);
  bool single;
  nsresult rv = GetSingle(&single);
  if (NS_FAILED(rv)) return rv;

  if (rowCount == 0 || (rowCount > 1 && single)) return NS_OK;

  mShiftSelectPivot = -1;

  // Invalidate not necessary when clearing selection, since
  // we're going to invalidate the world on the SelectAll.
  delete mFirstRange;

  mFirstRange = new nsTreeRange(this, 0, rowCount - 1);
  mFirstRange->Invalidate();

  FireOnSelectHandler();

  return NS_OK;
}

NS_IMETHODIMP nsTreeSelection::GetRangeCount(int32_t* aResult) {
  int32_t count = 0;
  nsTreeRange* curr = mFirstRange;
  while (curr) {
    count++;
    curr = curr->mNext;
  }

  *aResult = count;
  return NS_OK;
}

NS_IMETHODIMP nsTreeSelection::GetRangeAt(int32_t aIndex, int32_t* aMin,
                                          int32_t* aMax) {
  *aMin = *aMax = -1;
  int32_t i = -1;
  nsTreeRange* curr = mFirstRange;
  while (curr) {
    i++;
    if (i == aIndex) {
      *aMin = curr->mMin;
      *aMax = curr->mMax;
      break;
    }
    curr = curr->mNext;
  }

  return NS_OK;
}

NS_IMETHODIMP nsTreeSelection::GetCount(int32_t* count) {
  if (mFirstRange)
    *count = mFirstRange->Count();
  else  // No range available, so there's no selected row.
    *count = 0;

  return NS_OK;
}

NS_IMETHODIMP nsTreeSelection::GetSelectEventsSuppressed(
    bool* aSelectEventsSuppressed) {
  *aSelectEventsSuppressed = mSuppressed;
  return NS_OK;
}

NS_IMETHODIMP nsTreeSelection::SetSelectEventsSuppressed(
    bool aSelectEventsSuppressed) {
  mSuppressed = aSelectEventsSuppressed;
  if (!mSuppressed) FireOnSelectHandler();
  return NS_OK;
}

NS_IMETHODIMP nsTreeSelection::GetCurrentIndex(int32_t* aCurrentIndex) {
  *aCurrentIndex = mCurrentIndex;
  return NS_OK;
}

NS_IMETHODIMP nsTreeSelection::SetCurrentIndex(int32_t aIndex) {
  if (!mTree) {
    return NS_ERROR_UNEXPECTED;
  }
  if (mCurrentIndex == aIndex) {
    return NS_OK;
  }
  if (mCurrentIndex != -1 && mTree) mTree->InvalidateRow(mCurrentIndex);

  mCurrentIndex = aIndex;
  if (!mTree) return NS_OK;

  if (aIndex != -1) mTree->InvalidateRow(aIndex);

  // Fire DOMMenuItemActive or DOMMenuItemInactive event for tree.
  NS_ENSURE_STATE(mTree);

  constexpr auto DOMMenuItemActive = u"DOMMenuItemActive"_ns;
  constexpr auto DOMMenuItemInactive = u"DOMMenuItemInactive"_ns;

  RefPtr<AsyncEventDispatcher> asyncDispatcher = new AsyncEventDispatcher(
      mTree, (aIndex != -1 ? DOMMenuItemActive : DOMMenuItemInactive),
      CanBubble::eYes, ChromeOnlyDispatch::eNo);
  return asyncDispatcher->PostDOMEvent();
}

#define ADD_NEW_RANGE(macro_range, macro_selection, macro_start, macro_end) \
  {                                                                         \
    int32_t start = macro_start;                                            \
    int32_t end = macro_end;                                                \
    if (start > end) {                                                      \
      end = start;                                                          \
    }                                                                       \
    nsTreeRange* macro_new_range =                                          \
        new nsTreeRange(macro_selection, start, end);                       \
    if (macro_range)                                                        \
      macro_range->Insert(macro_new_range);                                 \
    else                                                                    \
      macro_range = macro_new_range;                                        \
  }

NS_IMETHODIMP
nsTreeSelection::AdjustSelection(int32_t aIndex, int32_t aCount) {
  NS_ASSERTION(aCount != 0, "adjusting by zero");
  if (!aCount) return NS_OK;

  // adjust mShiftSelectPivot, if necessary
  if ((mShiftSelectPivot != 1) && (aIndex <= mShiftSelectPivot)) {
    // if we are deleting and the delete includes the shift select pivot, reset
    // it
    if (aCount < 0 && (mShiftSelectPivot <= (aIndex - aCount - 1))) {
      mShiftSelectPivot = -1;
    } else {
      mShiftSelectPivot += aCount;
    }
  }

  // adjust mCurrentIndex, if necessary
  if ((mCurrentIndex != -1) && (aIndex <= mCurrentIndex)) {
    // if we are deleting and the delete includes the current index, reset it
    if (aCount < 0 && (mCurrentIndex <= (aIndex - aCount - 1))) {
      mCurrentIndex = -1;
    } else {
      mCurrentIndex += aCount;
    }
  }

  // no selection, so nothing to do.
  if (!mFirstRange) return NS_OK;

  bool selChanged = false;
  nsTreeRange* oldFirstRange = mFirstRange;
  nsTreeRange* curr = mFirstRange;
  mFirstRange = nullptr;
  while (curr) {
    if (aCount > 0) {
      // inserting
      if (aIndex > curr->mMax) {
        // adjustment happens after the range, so no change
        ADD_NEW_RANGE(mFirstRange, this, curr->mMin, curr->mMax);
      } else if (aIndex <= curr->mMin) {
        // adjustment happens before the start of the range, so shift down
        ADD_NEW_RANGE(mFirstRange, this, curr->mMin + aCount,
                      curr->mMax + aCount);
        selChanged = true;
      } else {
        // adjustment happen inside the range.
        // break apart the range and create two ranges
        ADD_NEW_RANGE(mFirstRange, this, curr->mMin, aIndex - 1);
        ADD_NEW_RANGE(mFirstRange, this, aIndex + aCount, curr->mMax + aCount);
        selChanged = true;
      }
    } else {
      // deleting
      if (aIndex > curr->mMax) {
        // adjustment happens after the range, so no change
        ADD_NEW_RANGE(mFirstRange, this, curr->mMin, curr->mMax);
      } else {
        // remember, aCount is negative
        selChanged = true;
        int32_t lastIndexOfAdjustment = aIndex - aCount - 1;
        if (aIndex <= curr->mMin) {
          if (lastIndexOfAdjustment < curr->mMin) {
            // adjustment happens before the start of the range, so shift up
            ADD_NEW_RANGE(mFirstRange, this, curr->mMin + aCount,
                          curr->mMax + aCount);
          } else if (lastIndexOfAdjustment >= curr->mMax) {
            // adjustment contains the range.  remove the range by not adding it
            // to the newRange
          } else {
            // adjustment starts before the range, and ends in the middle of it,
            // so trim the range
            ADD_NEW_RANGE(mFirstRange, this, aIndex, curr->mMax + aCount)
          }
        } else if (lastIndexOfAdjustment >= curr->mMax) {
          // adjustment starts in the middle of the current range, and contains
          // the end of the range, so trim the range
          ADD_NEW_RANGE(mFirstRange, this, curr->mMin, aIndex - 1)
        } else {
          // range contains the adjustment, so shorten the range
          ADD_NEW_RANGE(mFirstRange, this, curr->mMin, curr->mMax + aCount)
        }
      }
    }
    curr = curr->mNext;
  }

  delete oldFirstRange;

  // Fire the select event
  if (selChanged) FireOnSelectHandler();

  return NS_OK;
}

NS_IMETHODIMP
nsTreeSelection::InvalidateSelection() {
  if (mFirstRange) mFirstRange->Invalidate();
  return NS_OK;
}

NS_IMETHODIMP
nsTreeSelection::GetShiftSelectPivot(int32_t* aIndex) {
  *aIndex = mShiftSelectPivot;
  return NS_OK;
}

nsresult nsTreeSelection::FireOnSelectHandler() {
  if (mSuppressed || !mTree) {
    return NS_OK;
  }

  AsyncEventDispatcher::RunDOMEventWhenSafe(
      *mTree, u"select"_ns, CanBubble::eYes, ChromeOnlyDispatch::eNo);
  return NS_OK;
}

void nsTreeSelection::SelectCallback(nsITimer* aTimer, void* aClosure) {
  RefPtr<nsTreeSelection> self = static_cast<nsTreeSelection*>(aClosure);
  if (self) {
    self->FireOnSelectHandler();
    aTimer->Cancel();
    self->mSelectTimer = nullptr;
  }
}

///////////////////////////////////////////////////////////////////////////////////

nsresult NS_NewTreeSelection(XULTreeElement* aTree,
                             nsITreeSelection** aResult) {
  *aResult = new nsTreeSelection(aTree);
  if (!*aResult) return NS_ERROR_OUT_OF_MEMORY;
  NS_ADDREF(*aResult);
  return NS_OK;
}