// Aseprite
// Copyright (C) 2019-present  Igara Studio S.A.
// Copyright (C) 2001-2018  David Capello
//
// This program is distributed under the terms of
// the End-User License Agreement for Aseprite.

#ifdef HAVE_CONFIG_H
  #include "config.h"
#endif

#include "app/tools/tool_loop_manager.h"

#include "app/context.h"
#include "app/snap_to_grid.h"
#include "app/tools/controller.h"
#include "app/tools/ink.h"
#include "app/tools/intertwine.h"
#include "app/tools/point_shape.h"
#include "app/tools/symmetry.h"
#include "app/tools/tool_loop.h"
#include "app/tools/velocity.h"
#include "doc/brush.h"
#include "doc/image.h"
#include "doc/primitives.h"
#include "doc/sprite.h"
#include "gfx/point_io.h"
#include "gfx/rect_io.h"
#include "gfx/region.h"

#include <algorithm>
#include <climits>
#include <cmath>

#define TOOL_TRACE(...) // TRACEARGS(__VA_ARGS__)

namespace app { namespace tools {

using namespace gfx;
using namespace doc;
using namespace filters;

ToolLoopManager::ToolLoopManager(ToolLoop* toolLoop)
  : m_toolLoop(toolLoop)
  , m_canceled(false)
  , m_dynamics(toolLoop->getDynamics())
  , m_brush0(toolLoop->getBrush())
{
}

ToolLoopManager::~ToolLoopManager()
{
}

bool ToolLoopManager::isCanceled() const
{
  return m_canceled;
}

void ToolLoopManager::cancel()
{
  m_canceled = true;
}

void ToolLoopManager::end()
{
  if (m_canceled)
    m_toolLoop->rollback();
  else
    m_toolLoop->commit();
}

void ToolLoopManager::prepareLoop(const Pointer& pointer)
{
  // Start with no points at all
  m_stroke.reset();

  // Prepare the ink
  m_toolLoop->getInk()->prepareInk(m_toolLoop);
  m_toolLoop->getController()->prepareController(m_toolLoop);
  m_toolLoop->getIntertwine()->prepareIntertwine(m_toolLoop);
  m_toolLoop->getPointShape()->preparePointShape(m_toolLoop);
}

void ToolLoopManager::notifyToolLoopModifiersChange()
{
  if (isCanceled())
    return;

  if (m_lastPointer.button() != Pointer::None)
    movement(m_lastPointer);
}

void ToolLoopManager::pressButton(const Pointer& pointer)
{
  TOOL_TRACE("ToolLoopManager::pressButton", pointer.point());

  // A little patch to memorize initial Trace Policy in the
  // current function execution.
  // When the initial trace policy is "Last" and then
  // changes to different trace policy at the end of
  // this function, the user confirms a line draw while he
  // is holding the SHIFT key.
  bool tracePolicyWasLast = false;
  if (m_toolLoop->getTracePolicy() == TracePolicy::Last)
    tracePolicyWasLast = true;

  m_lastPointer = pointer;

  if (isCanceled())
    return;

  // If the user pressed the other mouse button...
  if ((m_toolLoop->getMouseButton() == ToolLoop::Left && pointer.button() == Pointer::Right) ||
      (m_toolLoop->getMouseButton() == ToolLoop::Right && pointer.button() == Pointer::Left)) {
    // Cancel the tool-loop (the destination image should be completely discarded)
    cancel();
    return;
  }

  m_stabilizerCenter = pointer.point();

  Stroke::Pt spritePoint = getSpriteStrokePt(pointer);
  m_toolLoop->getController()->pressButton(m_toolLoop, m_stroke, spritePoint);

  std::string statusText;
  m_toolLoop->getController()->getStatusBarText(m_toolLoop, m_stroke, statusText);
  m_toolLoop->updateStatusBar(statusText.c_str());

  // We evaluate if the trace policy has changed compared with
  // the initial trace policy.
  if (!(m_toolLoop->getTracePolicy() == TracePolicy::Last) && tracePolicyWasLast) {
    // Do nothing. We do not need execute an additional doLoopStep
    // (which it want to accumulate more points in m_pts in function
    // joinStroke() from intertwiners.h)
    // This avoid double print of a line while the user holds down
    // the SHIFT key.
  }
  else
    doLoopStep(false);
}

bool ToolLoopManager::releaseButton(const Pointer& pointer)
{
  TOOL_TRACE("ToolLoopManager::releaseButton", pointer.point());

  m_lastPointer = pointer;

  if (isCanceled())
    return false;

  if (m_toolLoop->getController()->isOnePoint() && m_toolLoop->getInk()->isSelection() &&
      !m_toolLoop->isPointInsideCanvas(pointer.point()))
    return false;

  Stroke::Pt spritePoint = getSpriteStrokePt(pointer);
  bool res = m_toolLoop->getController()->releaseButton(m_stroke, spritePoint);

  if (!res &&
      (m_toolLoop->getTracePolicy() == TracePolicy::Last || m_toolLoop->getInk()->isSelection() ||
       m_toolLoop->getInk()->isSlice() || m_toolLoop->getFilled())) {
    m_toolLoop->getInk()->setFinalStep(m_toolLoop, true);
    doLoopStep(true);
    m_toolLoop->getInk()->setFinalStep(m_toolLoop, false);
  }

  return res;
}

void ToolLoopManager::movement(Pointer pointer)
{
  // Filter points with the stabilizer
  if (m_dynamics.stabilizer && m_dynamics.stabilizerFactor > 0) {
    const double f = m_dynamics.stabilizerFactor;
    const gfx::Point delta = (pointer.point() - m_stabilizerCenter);
    const double distance = std::sqrt(delta.x * delta.x + delta.y * delta.y);

    const double angle = std::atan2(delta.y, delta.x);
    const gfx::PointF newPoint(m_stabilizerCenter.x + distance / f * std::cos(angle),
                               m_stabilizerCenter.y + distance / f * std::sin(angle));

    m_stabilizerCenter = newPoint;

    pointer = Pointer(gfx::Point(newPoint),
                      pointer.velocity(),
                      pointer.button(),
                      pointer.type(),
                      pointer.pressure());
  }

  m_lastPointer = pointer;

  if (isCanceled())
    return;

  Stroke::Pt spritePoint = getSpriteStrokePt(pointer);
  m_toolLoop->getController()->movement(m_toolLoop, m_stroke, spritePoint);

  std::string statusText;
  m_toolLoop->getController()->getStatusBarText(m_toolLoop, m_stroke, statusText);
  m_toolLoop->updateStatusBar(statusText.c_str());

  doLoopStep(false);
}

void ToolLoopManager::disableMouseStabilizer()
{
  // Disable mouse stabilizer for the current ToolLoopManager
  m_dynamics.stabilizer = false;
}

void ToolLoopManager::doLoopStep(bool lastStep)
{
  // Original set of points to interwine (original user stroke,
  // relative to sprite origin).
  Stroke main_stroke;
  if (!lastStep)
    m_toolLoop->getController()->getStrokeToInterwine(m_stroke, main_stroke);
  else
    main_stroke = m_stroke;

  // Calculate the area to be updated in all document observers.
  Symmetry* symmetry = m_toolLoop->getSymmetry();
  Strokes strokes;
  if (symmetry)
    symmetry->generateStrokes(main_stroke, strokes, m_toolLoop);
  else
    strokes.push_back(main_stroke);

  calculateDirtyArea(strokes);

  // If we are not in the last step (when the mouse button is
  // released) we are only showing a preview of the tool, so we can
  // limit the dirty area to the visible viewport bounds. In this way
  // the area using in validateoDstImage() can be a lot smaller.
  if (m_toolLoop->getTracePolicy() == TracePolicy::Last && !lastStep &&
      // We cannot limit the dirty area for LineFreehandController (or
      // in any case that the trace policy is handled by the
      // controller) just in case the user is using the Pencil tool
      // and used Shift+Click to draw a line and the origin point of
      // the line is not in the viewport area (e.g. for a very long
      // line, or with a lot of zoom in the end so the origin is not
      // viewable, etc.).
      !m_toolLoop->getController()->handleTracePolicy()) {
    m_toolLoop->limitDirtyAreaToViewport(m_dirtyArea);
  }

  // Validate source image area.
  if (m_toolLoop->getInk()->needsSpecialSourceArea()) {
    gfx::Region srcArea;
    m_toolLoop->getInk()->createSpecialSourceArea(m_dirtyArea, srcArea);
    m_toolLoop->validateSrcImage(srcArea);
  }
  else {
    m_toolLoop->validateSrcImage(m_dirtyArea);
  }

  m_toolLoop->getInk()->prepareForStrokes(m_toolLoop, strokes);

  // True when we have to fill
  const bool fillStrokes = (m_toolLoop->getFilled() &&
                            (lastStep || m_toolLoop->getPreviewFilled()));

  // Invalidate the whole destination image area.
  if (m_toolLoop->getTracePolicy() == TracePolicy::Last || fillStrokes) {
    // Copy source to destination (reset all the previous
    // traces). Useful for tools like Line and Ellipse (we keep the
    // last trace only) or to draw the final result in contour tool
    // (the final result is filled).
    m_toolLoop->invalidateDstImage();
    // Also reset the point shape variable for a new stroke. Useful
    // for Selection tools + TilePointShape.
    m_toolLoop->getPointShape()->prepareForStroke(m_toolLoop);
  }

  m_toolLoop->validateDstImage(m_dirtyArea);
  if (!lastStep && m_toolLoop->isSelectionToolLoop())
    m_toolLoop->clearSelectionToolMask(false);

  // Join or fill user points
  if (fillStrokes)
    m_toolLoop->getIntertwine()->fillStroke(m_toolLoop, main_stroke);
  else
    m_toolLoop->getIntertwine()->joinStroke(m_toolLoop, main_stroke);

  if (m_toolLoop->getTracePolicy() == TracePolicy::Overlap) {
    // Copy destination to source (yes, destination to source). In
    // this way each new trace overlaps the previous one.
    m_toolLoop->copyValidDstToSrcImage(m_dirtyArea);
  }

  if (!m_dirtyArea.isEmpty()) {
    m_toolLoop->validateDstTileset(m_dirtyArea);
    m_toolLoop->updateDirtyArea(m_dirtyArea);
  }

  TOOL_TRACE("ToolLoopManager::doLoopStep dirtyArea", m_dirtyArea.bounds());
}

// Applies the grid settings to the specified sprite point.
void ToolLoopManager::snapToGrid(Stroke::Pt& pt)
{
  if (!m_toolLoop->getController()->canSnapToGrid() || !m_toolLoop->getSnapToGrid() ||
      m_toolLoop->isSelectingTiles())
    return;

  gfx::Point point(pt.x, pt.y);
  point = snap_to_grid(m_toolLoop->getGridBounds(), point, PreferSnapTo::ClosestGridVertex);
  point += m_toolLoop->getBrush()->center();
  pt.x = point.x;
  pt.y = point.y;
}

// Strokes are relative to sprite origin.
void ToolLoopManager::calculateDirtyArea(const Strokes& strokes)
{
  // Save the current dirty area if it's needed
  Region prevDirtyArea;
  if (m_toolLoop->getTracePolicy() == TracePolicy::Last)
    prevDirtyArea = m_nextDirtyArea;

  // Start with a fresh dirty area
  m_dirtyArea.clear();

  for (auto& stroke : strokes) {
    gfx::Rect strokeBounds = m_toolLoop->getIntertwine()->getStrokeBounds(m_toolLoop, stroke);

    if (strokeBounds.isEmpty())
      continue;

    // Expand the dirty-area with the pen width
    Rect r1, r2;

    m_toolLoop->getPointShape()->getModifiedArea(m_toolLoop,
                                                 strokeBounds.x,
                                                 strokeBounds.y,
                                                 stroke.firstPoint().symmetry,
                                                 r1);

    m_toolLoop->getPointShape()->getModifiedArea(m_toolLoop,
                                                 strokeBounds.x + strokeBounds.w - 1,
                                                 strokeBounds.y + strokeBounds.h - 1,
                                                 stroke.firstPoint().symmetry,
                                                 r2);

    m_dirtyArea.createUnion(m_dirtyArea, Region(r1.createUnion(r2)));
  }

  // This ensures the Selection Tool Mask doesn't leave a 'trail' behind
  if (m_toolLoop->isSelectionToolLoop()) {
    auto bounds = m_dirtyArea.bounds();
    bounds.enlarge(1);
    m_dirtyArea |= gfx::Region(bounds);
  }

  // Merge new dirty area with the previous one (for tools like line
  // or rectangle it's needed to redraw the previous position and
  // the new one)
  if (m_toolLoop->getTracePolicy() == TracePolicy::Last) {
    m_nextDirtyArea = m_dirtyArea;
    m_dirtyArea.createUnion(m_dirtyArea, prevDirtyArea);
  }

  // Apply tiled mode
  TiledMode tiledMode = m_toolLoop->getTiledMode();
  if (tiledMode != TiledMode::NONE) {
    m_toolLoop->getTiledModeHelper().wrapPosition(m_dirtyArea);
    m_toolLoop->getTiledModeHelper().collapseRegionByTiledMode(m_dirtyArea);
  }
}

Stroke::Pt ToolLoopManager::getSpriteStrokePt(const Pointer& pointer)
{
  // Convert the screen point to a sprite point
  Stroke::Pt spritePoint = pointer.point();
  spritePoint.size = m_brush0->size();
  spritePoint.angle = m_brush0->angle();

  // Center the input to some grid point if needed
  snapToGrid(spritePoint);

  // Control dynamic parameters through sensors
  if (useDynamics()) {
    adjustPointWithDynamics(pointer, spritePoint);
  }

  // Inform the original velocity vector to the ToolLoop
  m_toolLoop->setSpeed(gfx::Point(pointer.velocity().x, pointer.velocity().y));

  return spritePoint;
}

bool ToolLoopManager::useDynamics() const
{
  return (m_dynamics.isDynamic() &&
          // TODO add support for dynamics to contour tool
          !m_toolLoop->getFilled() && m_toolLoop->getController()->isFreehand());
}

void ToolLoopManager::adjustPointWithDynamics(const Pointer& pointer, Stroke::Pt& pt)
{
  int size = pt.size;
  int angle = pt.angle;

  // Pressure
  bool hasP = (pointer.type() == Pointer::Type::Pen || pointer.type() == Pointer::Type::Eraser);
  float p = 1.0f;
  if (hasP) {
    p = pointer.pressure();
    if (p < m_dynamics.minPressureThreshold) {
      p = 0.0f;
    }
    else if (p > m_dynamics.maxPressureThreshold ||
             // To avoid div by zero
             m_dynamics.minPressureThreshold == m_dynamics.maxPressureThreshold) {
      p = 1.0f;
    }
    else {
      p = (p - m_dynamics.minPressureThreshold) /
          (m_dynamics.maxPressureThreshold - m_dynamics.minPressureThreshold);
    }
  }
  ASSERT(p >= 0.0f && p <= 1.0f);
  p = std::clamp(p, 0.0f, 1.0f);

  // Velocity
  float v = pointer.velocity().magnitude() / VelocitySensor::kScreenPixelsForFullVelocity;
  v = std::clamp(v, 0.0f, 1.0f);
  if (v < m_dynamics.minVelocityThreshold) {
    v = 0.0f;
  }
  else if (v > m_dynamics.maxVelocityThreshold ||
           // To avoid div by zero
           m_dynamics.minVelocityThreshold == m_dynamics.maxVelocityThreshold) {
    v = 1.0f;
  }
  else {
    v = (v - m_dynamics.minVelocityThreshold) /
        (m_dynamics.maxVelocityThreshold - m_dynamics.minVelocityThreshold);
  }
  ASSERT(v >= 0.0f && v <= 1.0f);
  v = std::clamp(v, 0.0f, 1.0f);

  switch (m_dynamics.size) {
    case DynamicSensor::Pressure:
      if (hasP)
        size = (1.0f - p) * m_dynamics.minSize + p * size;
      break;
    case DynamicSensor::Velocity: size = (1.0f - v) * m_dynamics.minSize + v * size; break;
  }

  switch (m_dynamics.angle) {
    case DynamicSensor::Pressure:
      if (hasP)
        angle = (1.0f - p) * m_dynamics.minAngle + p * angle;
      break;
    case DynamicSensor::Velocity: angle = (1.0f - v) * m_dynamics.minAngle + v * angle; break;
  }

  switch (m_dynamics.gradient) {
    case DynamicSensor::Pressure: pt.gradient = p; break;
    case DynamicSensor::Velocity: pt.gradient = v; break;
  }

  pt.size = std::clamp(size, int(Brush::kMinBrushSize), int(Brush::kMaxBrushSize));
  pt.angle = std::clamp(angle, -180, 180);
}

}} // namespace app::tools
