/**
 * \file line-snapper.cpp
 * \brief LineSnapper class.
 *
 * Authors:
 *   Diederik van Lierop <mail@diedenrezi.nl>
 *   And others...
 *
 * Copyright (C) 1999-2008 Authors
 *
 * Released under GNU GPL, read the file 'COPYING' for more information
 */

#include <2geom/line.h>
#include "line-snapper.h"
#include "snapped-line.h"
//#include <gtk/gtk.h>
#include "snap.h"

Inkscape::LineSnapper::LineSnapper(SnapManager *sm, Geom::Coord const d) : Snapper(sm, d)
{
}

void Inkscape::LineSnapper::freeSnap(SnappedConstraints &sc,
                                                    Inkscape::SnapPreferences::PointType const &t,
                                                    Inkscape::SnapCandidatePoint const &p,
                                                    Geom::OptRect const &/*bbox_to_snap*/,
                                                    std::vector<SPItem const *> const */*it*/,
                                                    std::vector<Inkscape::SnapCandidatePoint> */*unselected_nodes*/) const
{
    if (!(_snap_enabled && _snapmanager->snapprefs.getSnapFrom(t)) ) {
        return;
    }

    /* Get the lines that we will try to snap to */
    const LineList lines = _getSnapLines(p.getPoint());

    for (LineList::const_iterator i = lines.begin(); i != lines.end(); i++) {
        Geom::Point const p1 = i->second; // point at guide/grid line
        Geom::Point const p2 = p1 + Geom::rot90(i->first); // 2nd point at guide/grid line
        // std::cout << "  line through " << i->second << " with normal " << i->first;
        g_assert(i->first != Geom::Point(0,0)); // we cannot project on an linesegment of zero length

        Geom::Point const p_proj = Geom::projection(p.getPoint(), Geom::Line(p1, p2));
        Geom::Coord const dist = Geom::L2(p_proj - p.getPoint());
        //Store any line that's within snapping range
        if (dist < getSnapperTolerance()) {
            _addSnappedLine(sc, p_proj, dist, p.getSourceType(), p.getSourceNum(), i->first, i->second);
            // For any line that's within range, we will also look at it's "point on line" p1. For guides
            // this point coincides with its origin; for grids this is of no use, but we cannot
            // discern between grids and guides here
            Geom::Coord const dist_p1 = Geom::L2(p1 - p.getPoint());
            if (dist_p1 < getSnapperTolerance()) {
                _addSnappedLinesOrigin(sc, p1, dist_p1, p.getSourceType(), p.getSourceNum());
                // Only relevant for guides; grids don't have an origin per line
                // Therefore _addSnappedLinesOrigin() will only be implemented for guides
            }
            // std::cout << " -> distance = " << dist;
        }
        // std::cout << std::endl;
    }
}

void Inkscape::LineSnapper::constrainedSnap(SnappedConstraints &sc,
                                               Inkscape::SnapPreferences::PointType const &t,
                                               Inkscape::SnapCandidatePoint const &p,
                                               Geom::OptRect const &/*bbox_to_snap*/,
                                               ConstraintLine const &c,
                                               std::vector<SPItem const *> const */*it*/) const

{
    if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(t) == false) {
        return;
    }

    /* Get the lines that we will try to snap to */
    const LineList lines = _getSnapLines(p.getPoint());

    for (LineList::const_iterator i = lines.begin(); i != lines.end(); i++) {
        if (Geom::L2(c.getDirection()) > 0) { // Can't do a constrained snap without a constraint
            // constraint line
            Geom::Point const point_on_line = c.hasPoint() ? c.getPoint() : p.getPoint();
            Geom::Line line1(point_on_line, point_on_line + c.getDirection());

            // grid/guide line
            Geom::Point const p1 = i->second; // point at guide/grid line
            Geom::Point const p2 = p1 + Geom::rot90(i->first); // 2nd point at guide/grid line
            Geom::Line line2(p1, p2);

            Geom::OptCrossing inters = Geom::OptCrossing(); // empty by default
            try
            {
                inters = Geom::intersection(line1, line2);
            }
            catch (Geom::InfiniteSolutions e)
            {
                // We're probably dealing with parallel lines, so snapping doesn't make any sense here
                continue; // jump to the next iterator in the for-loop
            }

            if (inters) {
                Geom::Point t = line1.pointAt((*inters).ta);
                const Geom::Coord dist = Geom::L2(t - p.getPoint());
                if (dist < getSnapperTolerance()) {
                    // When doing a constrained snap, we're already at an intersection.
                    // This snappoint is therefore fully constrained, so there's no need
                    // to look for additional intersections; just return the snapped point
                    // and forget about the line
                    _addSnappedPoint(sc, t, dist, p.getSourceType(), p.getSourceNum());
                    // For any line that's within range, we will also look at it's "point on line" p1. For guides
                    // this point coincides with its origin; for grids this is of no use, but we cannot
                    // discern between grids and guides here
                    Geom::Coord const dist_p1 = Geom::L2(p1 - p.getPoint());
                    if (dist_p1 < getSnapperTolerance()) {
                        _addSnappedLinesOrigin(sc, p1, dist_p1, p.getSourceType(), p.getSourceNum());
                        // Only relevant for guides; grids don't have an origin per line
                        // Therefore _addSnappedLinesOrigin() will only be implemented for guides
                    }
                }
            }
        }
    }
}

// Will only be overridden in the guide-snapper class, because grid lines don't have an origin; the
// grid-snapper classes will use this default empty method
void Inkscape::LineSnapper::_addSnappedLinesOrigin(SnappedConstraints &/*sc*/, Geom::Point const /*origin*/, Geom::Coord const /*snapped_distance*/, SnapSourceType const &/*source_type*/, long /*source_num*/) const
{
}

/*
  Local Variables:
  mode:c++
  c-file-style:"stroustrup"
  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
  indent-tabs-mode:nil
  fill-column:99
  End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :