//#define use_int32

#include <emscripten.h>
#include "clipper.hpp"

typedef unsigned char Uint8;
typedef unsigned short Uint16;
typedef unsigned int Uint32;
typedef int int32;

using namespace ClipperLib;

Uint8 *mem = 0;
const Uint8 debug = 0;

extern "C" {
    extern void polygon(Uint32 points, Uint32 inners);
    extern void point(Uint32 x, Uint32 y);
    extern void abc(Uint32 a, Uint32 b, Uint32 c);
}

struct length16 {
    Uint16 length;
};

struct point32 {
    int32 x;
    int32 y;
};

__attribute__ ((export_name("mem_get")))
Uint32 mem_get(Uint32 size) {
    return (Uint32)malloc(size);
}

__attribute__ ((export_name("mem_clr")))
void mem_clr(Uint32 loc) {
    free((void *)loc);
}

Uint32 readPolys(Paths paths, Uint32 pos, Uint32 count) {
    Uint32 poly = 0;
    if (debug) abc(poly, count, pos);
    while (count > 0) {
        struct length16 *ls = (struct length16 *)(mem + pos);
        Uint16 points = ls->length;
        if (debug) polygon(points, 0);
        pos += 2;
        while (points-- > 0) {
            struct point32 *ip = (struct point32 *)(mem + pos);
            pos += 8;
            paths[poly] << IntPoint(ip->x, ip->y);
            if (debug) point(ip->x, ip->y);
        }
        poly++;
        count--;
    }
    if (debug) abc(poly, count, pos);
    return pos;
}

__attribute__ ((export_name("poly_offset")))
Uint32 poly_offset(Uint32 memat, Uint32 polys, float offset) {

    Paths ins(polys);
    Paths outs;
    Uint32 pos = memat;
    Uint16 poly = 0;

    // pos = readPolys(ins, pos, polys);

    while (poly < polys) {
        struct length16 *ls = (struct length16 *)(mem + pos);
        Uint16 points = ls->length;
        if (debug) polygon(points, 0);
        pos += 2;
        while (points-- > 0) {
            struct point32 *ip = (struct point32 *)(mem + pos);
            pos += 8;
            ins[poly] << IntPoint(ip->x, ip->y);
            if (debug) point(ip->x, ip->y);
        }
        poly++;
    }

    if (debug) abc(memat, pos, memat - pos);

    // clean and simplify polygons
    // Paths cleans, simples;
    // CleanPolygons(ins, cleans, 250);
    // SimplifyPolygons(cleans, simples, pftNonZero);
    // ins = simples;

    ClipperOffset co;
    co.AddPaths(ins, jtMiter, etClosedPolygon);
    co.Execute(outs, offset);

    Uint32 resat = pos;

    for (Path po : outs) {
        if (debug) polygon(po.size(), 1);
        struct length16 *ls = (struct length16 *)(mem + pos);
        ls->length = po.size();
        pos += 2;
        for (IntPoint pt : po) {
            if (debug) point(pt.X, pt.Y);
            struct point32 *ip = (struct point32 *)(mem + pos);
            ip->x = (int)pt.X;
            ip->y = (int)pt.Y;
            pos += 8;
        }
    }

    // null terminate
    struct length16 *ls = (struct length16 *)(mem + pos);
    ls->length = 0;

    co.Clear();

    return resat;
}

__attribute__ ((export_name("poly_union")))
Uint32 poly_union(Uint32 memat, Uint32 polys, float offset) {

    Paths ins(polys);
    Paths outs;
    Uint32 pos = memat;
    Uint16 poly = 0;

    while (poly < polys) {
        struct length16 *ls = (struct length16 *)(mem + pos);
        Uint16 points = ls->length;
        pos += 2;
        while (points-- > 0) {
            struct point32 *ip = (struct point32 *)(mem + pos);
            pos += 8;
            ins[poly] << IntPoint(ip->x, ip->y);
        }
        poly++;
    }

    Clipper clip;
    clip.AddPaths(ins, ptSubject, true);
    clip.Execute(ctUnion, outs);

    Uint32 resat = pos;

    for (Path po : outs) {
        struct length16 *ls = (struct length16 *)(mem + pos);
        ls->length = po.size();
        pos += 2;
        for (IntPoint pt : po) {
            struct point32 *ip = (struct point32 *)(mem + pos);
            ip->x = (int)pt.X;
            ip->y = (int)pt.Y;
            pos += 8;
        }
    }

    // null terminate
    struct length16 *ls = (struct length16 *)(mem + pos);
    ls->length = 0;

    clip.Clear();

    return resat;
}



__attribute__ ((export_name("poly_diff")))
Uint32 poly_diff(Uint32 memat, Uint32 polysA, Uint32 polysB, float offset) {

    Paths inA(polysA);
    Paths inB(polysB);
    Paths outs;
    Uint32 pos = memat;

    for (Uint32 poly = 0; poly < polysA; poly++ ) {
        struct length16 *ls = (struct length16 *)(mem + pos);
        Uint16 points = ls->length;
        pos += 2;
        while (points-- > 0) {
            struct point32 *ip = (struct point32 *)(mem + pos);
            pos += 8;
            inA[poly] << IntPoint(ip->x, ip->y);
        }
        poly++;
    }

    for (Uint32 poly = 0; poly < polysB; poly++ ) {
        struct length16 *ls = (struct length16 *)(mem + pos);
        Uint16 points = ls->length;
        pos += 2;
        while (points-- > 0) {
            struct point32 *ip = (struct point32 *)(mem + pos);
            pos += 8;
            inB[poly] << IntPoint(ip->x, ip->y);
        }
        poly++;
    }

    Clipper clip;
    clip.AddPaths(inA, ptSubject, true);
    clip.AddPaths(inB, ptClip, true);
    clip.Execute(ctDifference, outs, pftEvenOdd, pftEvenOdd);

    Uint32 resat = pos;

    for (Path po : outs) {
        struct length16 *ls = (struct length16 *)(mem + pos);
        ls->length = po.size();
        pos += 2;
        for (IntPoint pt : po) {
            struct point32 *ip = (struct point32 *)(mem + pos);
            ip->x = (int)pt.X;
            ip->y = (int)pt.Y;
            pos += 8;
        }
    }

    // null terminate
    struct length16 *ls = (struct length16 *)(mem + pos);
    ls->length = 0;

    clip.Clear();

    return resat;
}