/* 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/. */

/* Utility code for performing CSS Box Alignment */

#ifndef mozilla_CSSAlignUtils_h
#define mozilla_CSSAlignUtils_h

#include "mozilla/EnumSet.h"
#include "mozilla/WritingModes.h"

namespace mozilla {

struct ReflowInput;
struct StyleAlignFlags;

class CSSAlignUtils {
 public:
  /**
   * Map a raw StyleAlignFlags value to the used one.
   */
  static StyleAlignFlags UsedAlignmentForAbsPos(nsIFrame* aFrame,
                                                StyleAlignFlags aFlags,
                                                LogicalAxis aLogicalAxis,
                                                WritingMode aCBWM);

  /**
   * Flags to customize the behavior of AlignJustifySelf:
   */
  enum class AlignJustifyFlag {
    // Indicates that we have <overflow-position> = safe.
    OverflowSafe,

    // Indicates that the container's start side in aAxis is the same
    // as the child's start side in the child's parallel axis.
    SameSide,

    // Indicates that AlignJustifySelf() shouldn't expand "auto" margins.
    // (By default, AlignJustifySelf() *will* expand such margins, to fill the
    // available space before any alignment is done.)
    IgnoreAutoMargins,

    // We're aligning a margin box - the margin is already included in the
    // size. Implies `IgnoreAutoMargins`.
    AligningMarginBox,

    // If the item is baseline-aligned, this flag indicates that the item is in
    // the last baseline sharing group of the container, otherwise the item is
    // in the container's first baseline sharing group.
    LastBaselineSharingGroup,
  };
  using AlignJustifyFlags = EnumSet<AlignJustifyFlag>;

  /**
   * Additional information required to resolve anchor-center on a particular
   * axis.
   */
  struct AnchorAlignInfo {
    nscoord mAnchorStart;
    nscoord mAnchorSize;
  };

  /**
   * This computes the aligned offset of a CSS-aligned child within its
   * alignment container. The returned offset is distance between the
   * logical "start" edge of the alignment container & the logical "start" edge
   * of the aligned child (in terms of the alignment container's writing mode).
   *
   * @param aAlignment An enumerated value representing a keyword for
   *                   "align-self" or "justify-self". The values
   *                   StyleAlignFlags::{AUTO,LEFT,RIGHT} must *not* be
   *                   passed here; this method expects the caller to have
   *                   already resolved those to 'start', 'end', or 'stretch'.
   * @param aAxis The container's axis in which we're doing alignment.
   * @param aBaselineAdjust The amount to offset baseline-aligned children.
   * @param aCBSize The size of the alignment container, in its aAxis.
   * @param aRI A ReflowInput for the child.
   * @param aChildSize The child's LogicalSize (in its own writing mode).
   * @param aAnchorInfo When specified, an inset-modified anchor start and size
   * (in the child's writing mode) to use for anchor-center alignment.
   */
  static nscoord AlignJustifySelf(
      const StyleAlignFlags& aAlignment, LogicalAxis aAxis,
      AlignJustifyFlags aFlags, nscoord aBaselineAdjust, nscoord aCBSize,
      const ReflowInput& aRI, const LogicalSize& aChildSize,
      const Maybe<AnchorAlignInfo>& aAnchorRect = Nothing());
};

}  // namespace mozilla

#endif  // mozilla_CSSAlignUtils_h