// JavaScript implementations of point-in-polygon testing.
// Adapted by Andrew Cameron from Dan Sunday's algorithm and C++
// implementation, whose copyright follows.
//
// Copyright 2000 softSurfer, 2012 Dan Sunday
// This code may be freely used, distributed and modified for any purpose
// providing that this copyright notice is included with it.
// SoftSurfer makes no warranty for this code, and cannot be held
// liable for any real or imagined damage resulting from its use.
// Users of this code must verify correctness for their application.

"use strict";
var isLeft = function (l0, l1, p) {
    return ((l1[0] - l0[0]) * (p[1] - l0[1])
            - (p[0] - l0[0]) * (l1[1] - l0[1]));
};

var inPoly = function (p, v, direction, axis) {
    var wn = 0; // winding number counter
    var dir = 0;
    if (direction > 0) {
        dir = 1;
    } else if (direction < 0) {
        dir = -1;
    } else {
        error('wat');
    }

    if (axis != 0 && axis != 1) {
        error('wat');
    }

    v.forEach(function (curPt, idx, arr) {
        var nextPt;
        if (idx < arr.length - 1) {
            nextPt = arr[idx + 1];
        } else {
            nextPt = arr[0];
        }

        if (dir * curPt[axis] <= dir * p[axis]) {
            if (dir * nextPt[axis] > dir * p[axis]) {
                if (isLeft(curPt, nextPt, p) > 0) {
                    wn++;
                }
            }
        } else {
            if (dir * nextPt[axis] <= dir * p[axis]) {
                if (isLeft(curPt, nextPt, p) < 0) {
                    wn--;
                }
            }
        }
    });

    return wn;
};

var countZones = function(polygons, points, binPoints) {
    var counts = {};
    polygons.forEach(function (poly, idx, arr) {
        counts[poly.name] = 0;
    }, this);
    counts['undetermined'] = 0;
    points.forEach(function (pt, idx_pt, arr_pts) {
        if (!polygons.some(function (poly, idx_poly, arr_polys) {
            if (inPoly(pt, poly.path, 1, 0) != 0 ||
               inPoly(pt, poly.path, -1, 0) != 0 ||
               inPoly(pt, poly.path, 1, 1) != 0 ||
               inPoly(pt, poly.path, -1, 1) != 0) {
                counts[poly.name] += 1;
                if (binPoints == true) {
                    pt.push(poly.name);
                }
                return true;
            } else {
                return false;
            }
        }, this)) { // not found in any of the polygons
            counts['undetermined'] += 1;
            if (binPoints == true) {
                pt.push('undetermined');
            }
        }
    }, this);
    return counts;
};