/*
 * Copyright (c) 2020 Samsung Electronics Co., Ltd. All rights reserved.

 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:

 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
#include "tvgSwCommon.h"

/************************************************************************/
/* Internal Class Implementation                                        */
/************************************************************************/

struct Line
{
    Point pt1;
    Point pt2;
};


static SwPoint _transform(const Point* to, const Matrix* transform)
{
    if (!transform) return {TO_SWCOORD(to->x), TO_SWCOORD(to->y)};

    auto tx = round(to->x * transform->e11 + to->y * transform->e12 + transform->e13);
    auto ty = round(to->x * transform->e21 + to->y * transform->e22 + transform->e23);

    return {TO_SWCOORD(tx), TO_SWCOORD(ty)};
}


static float _lineLength(const Point& pt1, const Point& pt2)
{
    /* approximate sqrt(x*x + y*y) using alpha max plus beta min algorithm.
       With alpha = 1, beta = 3/8, giving results with the largest error less
       than 7% compared to the exact value. */
    Point diff = {pt2.x - pt1.x, pt2.y - pt1.y};
    if (diff.x < 0) diff.x = -diff.x;
    if (diff.y < 0) diff.y = -diff.y;
    return (diff.x > diff.y) ? (diff.x + diff.y * 0.375f) : (diff.y + diff.x * 0.375f);
}


static void _lineSplitAt(const Line& cur, float at, Line& left, Line& right)
{
    auto len = _lineLength(cur.pt1, cur.pt2);
    auto dx = ((cur.pt2.x - cur.pt1.x) / len) * at;
    auto dy = ((cur.pt2.y - cur.pt1.y) / len) * at;
    left.pt1 = cur.pt1;
    left.pt2.x = left.pt1.x + dx;
    left.pt2.y = left.pt1.y + dy;
    right.pt1 = left.pt2;
    right.pt2 = cur.pt2;
}


static void _growOutlineContour(SwOutline& outline, uint32_t n)
{
    if (outline.reservedCntrsCnt >= outline.cntrsCnt + n) return;
    outline.reservedCntrsCnt = outline.cntrsCnt + n;
    outline.cntrs = static_cast<uint32_t*>(realloc(outline.cntrs, outline.reservedCntrsCnt * sizeof(uint32_t)));
}


static void _growOutlinePoint(SwOutline& outline, uint32_t n)
{
    if (outline.reservedPtsCnt >= outline.ptsCnt + n) return;
    outline.reservedPtsCnt = outline.ptsCnt + n;
    outline.pts = static_cast<SwPoint*>(realloc(outline.pts, outline.reservedPtsCnt * sizeof(SwPoint)));
    outline.types = static_cast<uint8_t*>(realloc(outline.types, outline.reservedPtsCnt * sizeof(uint8_t)));
}


static void _delOutline(SwOutline* outline)
{
    if (!outline) return;

    if (outline->cntrs) free(outline->cntrs);
    if (outline->pts) free(outline->pts);
    if (outline->types) free(outline->types);
    free(outline);
}


static void _outlineEnd(SwOutline& outline)
{
    _growOutlineContour(outline, 1);
    if (outline.ptsCnt > 0) {
        outline.cntrs[outline.cntrsCnt] = outline.ptsCnt - 1;
        ++outline.cntrsCnt;
    }
}


static void _outlineMoveTo(SwOutline& outline, const Point* to, const Matrix* transform)
{
    _growOutlinePoint(outline, 1);

    outline.pts[outline.ptsCnt] = _transform(to, transform);

    outline.types[outline.ptsCnt] = SW_CURVE_TYPE_POINT;

    if (outline.ptsCnt > 0) {
        _growOutlineContour(outline, 1);
        outline.cntrs[outline.cntrsCnt] = outline.ptsCnt - 1;
        ++outline.cntrsCnt;
    }

    ++outline.ptsCnt;
}


static void _outlineLineTo(SwOutline& outline, const Point* to, const Matrix* transform)
{
    _growOutlinePoint(outline, 1);

    outline.pts[outline.ptsCnt] = _transform(to, transform);
    outline.types[outline.ptsCnt] = SW_CURVE_TYPE_POINT;
    ++outline.ptsCnt;
}


static void _outlineCubicTo(SwOutline& outline, const Point* ctrl1, const Point* ctrl2, const Point* to, const Matrix* transform)
{
    _growOutlinePoint(outline, 3);

    outline.pts[outline.ptsCnt] = _transform(ctrl1, transform);
    outline.types[outline.ptsCnt] = SW_CURVE_TYPE_CUBIC;
    ++outline.ptsCnt;

    outline.pts[outline.ptsCnt] = _transform(ctrl2, transform);
    outline.types[outline.ptsCnt] = SW_CURVE_TYPE_CUBIC;
    ++outline.ptsCnt;

    outline.pts[outline.ptsCnt] = _transform(to, transform);
    outline.types[outline.ptsCnt] = SW_CURVE_TYPE_POINT;
    ++outline.ptsCnt;
}


static void _outlineClose(SwOutline& outline)
{
    uint32_t i = 0;

    if (outline.cntrsCnt > 0) {
        i = outline.cntrs[outline.cntrsCnt - 1] + 1;
    } else {
        i = 0;   //First Path
    }

    //Make sure there is at least one point in the current path
    if (outline.ptsCnt == i) {
        outline.opened = true;
        return;
    }

    //Close the path
    _growOutlinePoint(outline, 1);

    outline.pts[outline.ptsCnt] = outline.pts[i];
    outline.types[outline.ptsCnt] = SW_CURVE_TYPE_POINT;
    ++outline.ptsCnt;

    outline.opened = false;
}


static void _initBBox(SwBBox& bbox)
{
    bbox.min.x = bbox.min.y = 0;
    bbox.max.x = bbox.max.y = 0;
}


static bool _updateBBox(SwOutline* outline, SwBBox& bbox)
{
    if (!outline) return false;

    auto pt = outline->pts;

    if (outline->ptsCnt <= 0) {
        _initBBox(bbox);
        return false;
    }

    auto xMin = pt->x;
    auto xMax = pt->x;
    auto yMin = pt->y;
    auto yMax = pt->y;

    ++pt;

    for(uint32_t i = 1; i < outline->ptsCnt; ++i, ++pt) {
        if (xMin > pt->x) xMin = pt->x;
        if (xMax < pt->x) xMax = pt->x;
        if (yMin > pt->y) yMin = pt->y;
        if (yMax < pt->y) yMax = pt->y;
    }
    bbox.min.x = xMin >> 6;
    bbox.max.x = (xMax + 63) >> 6;
    bbox.min.y = yMin >> 6;
    bbox.max.y = (yMax + 63) >> 6;

    if (xMax - xMin < 1 && yMax - yMin < 1) return false;

    return true;
}


static bool _checkValid(const SwOutline* outline, const SwBBox& bbox, const SwSize& clip)
{
    if (outline->ptsCnt == 0 || outline->cntrsCnt <= 0) return false;

    //Check boundary
    if (bbox.min.x >= clip.w || bbox.min.y >= clip.h || bbox.max.x <= 0 || bbox.max.y <= 0) return false;

    return true;
}


static void _dashLineTo(SwDashStroke& dash, const Point* to, const Matrix* transform)
{
    _growOutlinePoint(*dash.outline, dash.outline->ptsCnt >> 1);
    _growOutlineContour(*dash.outline, dash.outline->cntrsCnt >> 1);

    Line cur = {dash.ptCur, *to};
    auto len = _lineLength(cur.pt1, cur.pt2);

    if (len < dash.curLen) {
        dash.curLen -= len;
        if (!dash.curOpGap) {
            _outlineMoveTo(*dash.outline, &dash.ptCur, transform);
            _outlineLineTo(*dash.outline, to, transform);
        }
    } else {
        while (len > dash.curLen) {
            len -= dash.curLen;
            Line left, right;
            _lineSplitAt(cur, dash.curLen, left, right);;
            dash.curIdx = (dash.curIdx + 1) % dash.cnt;
            if (!dash.curOpGap) {
                _outlineMoveTo(*dash.outline, &left.pt1, transform);
                _outlineLineTo(*dash.outline, &left.pt2, transform);
            }
            dash.curLen = dash.pattern[dash.curIdx];
            dash.curOpGap = !dash.curOpGap;
            cur = right;
            dash.ptCur = cur.pt1;
        }
        //leftovers
        dash.curLen -= len;
        if (!dash.curOpGap) {
            _outlineMoveTo(*dash.outline, &cur.pt1, transform);
            _outlineLineTo(*dash.outline, &cur.pt2, transform);
        }
        if (dash.curLen < 1) {
            //move to next dash
            dash.curIdx = (dash.curIdx + 1) % dash.cnt;
            dash.curLen = dash.pattern[dash.curIdx];
            dash.curOpGap = !dash.curOpGap;
        }
    }
    dash.ptCur = *to;
}


static void _dashCubicTo(SwDashStroke& dash, const Point* ctrl1, const Point* ctrl2, const Point* to, const Matrix* transform)
{
    _growOutlinePoint(*dash.outline, dash.outline->ptsCnt >> 1);
    _growOutlineContour(*dash.outline, dash.outline->cntrsCnt >> 1);

    Bezier cur = { dash.ptCur, *ctrl1, *ctrl2, *to};
    auto len = bezLength(cur);

    if (len < dash.curLen) {
        dash.curLen -= len;
        if (!dash.curOpGap) {
            _outlineMoveTo(*dash.outline, &dash.ptCur, transform);
            _outlineCubicTo(*dash.outline, ctrl1, ctrl2, to, transform);
        }
    } else {
        while (len > dash.curLen) {
            Bezier left, right;
            len -= dash.curLen;
            bezSplitAt(cur, dash.curLen, left, right);
            dash.curIdx = (dash.curIdx + 1) % dash.cnt;
            if (!dash.curOpGap) {
                _outlineMoveTo(*dash.outline, &left.start, transform);
                _outlineCubicTo(*dash.outline, &left.ctrl1, &left.ctrl2, &left.end, transform);
            }
            dash.curLen = dash.pattern[dash.curIdx];
            dash.curOpGap = !dash.curOpGap;
            cur = right;
            dash.ptCur = right.start;
        }
        //leftovers
        dash.curLen -= len;
        if (!dash.curOpGap) {
            _outlineMoveTo(*dash.outline, &cur.start, transform);
            _outlineCubicTo(*dash.outline, &cur.ctrl1, &cur.ctrl2, &cur.end, transform);
        }
        if (dash.curLen < 1) {
            //move to next dash
            dash.curIdx = (dash.curIdx + 1) % dash.cnt;
            dash.curLen = dash.pattern[dash.curIdx];
            dash.curOpGap = !dash.curOpGap;
        }
    }
    dash.ptCur = *to;
}


SwOutline* _genDashOutline(const Shape* sdata, const Matrix* transform)
{
    const PathCommand* cmds = nullptr;
    auto cmdCnt = sdata->pathCommands(&cmds);

    const Point* pts = nullptr;
    auto ptsCnt = sdata->pathCoords(&pts);

    //No actual shape data
    if (cmdCnt == 0 || ptsCnt == 0) return nullptr;

    SwDashStroke dash;
    dash.curIdx = 0;
    dash.curLen = 0;
    dash.ptStart = {0, 0};
    dash.ptCur = {0, 0};
    dash.curOpGap = false;

    const float* pattern;
    dash.cnt = sdata->strokeDash(&pattern);
    if (dash.cnt == 0) return nullptr;

    //Is it safe to mutual exclusive?
    dash.pattern = const_cast<float*>(pattern);
    dash.outline = static_cast<SwOutline*>(calloc(1, sizeof(SwOutline)));
    dash.outline->opened = true;

    //smart reservation
    auto outlinePtsCnt = 0;
    auto outlineCntrsCnt = 0;

    for (uint32_t i = 0; i < cmdCnt; ++i) {
        switch(*(cmds + i)) {
            case PathCommand::Close: {
                ++outlinePtsCnt;
                break;
            }
            case PathCommand::MoveTo: {
                ++outlineCntrsCnt;
                ++outlinePtsCnt;
                break;
            }
            case PathCommand::LineTo: {
                ++outlinePtsCnt;
                break;
            }
            case PathCommand::CubicTo: {
                outlinePtsCnt += 3;
                break;
            }
        }
    }

    ++outlinePtsCnt;    //for close
    ++outlineCntrsCnt;  //for end

    //Reserve Approximitely 20x...
    _growOutlinePoint(*dash.outline, outlinePtsCnt * 20);
    _growOutlineContour(*dash.outline, outlineCntrsCnt * 20);

    while (cmdCnt-- > 0) {
        switch(*cmds) {
            case PathCommand::Close: {
                _dashLineTo(dash, &dash.ptStart, transform);
                break;
            }
            case PathCommand::MoveTo: {
                //reset the dash
                dash.curIdx = 0;
                dash.curLen = *dash.pattern;
                dash.curOpGap = false;
                dash.ptStart = dash.ptCur = *pts;
                ++pts;
                break;
            }
            case PathCommand::LineTo: {
                _dashLineTo(dash, pts, transform);
                ++pts;
                break;
            }
            case PathCommand::CubicTo: {
                _dashCubicTo(dash, pts, pts + 1, pts + 2, transform);
                pts += 3;
                break;
            }
        }
        ++cmds;
    }

    _outlineEnd(*dash.outline);

    return dash.outline;
}


bool _fastTrack(const SwOutline* outline)
{
    //Fast Track: Othogonal rectangle?
    if (outline->ptsCnt != 5) return false;

    auto pt1 = outline->pts + 0;
    auto pt2 = outline->pts + 1;
    auto pt3 = outline->pts + 2;
    auto pt4 = outline->pts + 3;

    auto min1 = pt1->y < pt3->y ? pt1 : pt3;
    auto min2 = pt2->y < pt4->y ? pt2 : pt4;
    if (min1->y != min2->y) return false;

    SwCoord len1 = pow(pt1->x - pt3->x, 2) + pow(pt1->y - pt3->y, 2);
    SwCoord len2 = pow(pt2->x - pt4->x, 2) + pow(pt2->y - pt4->y, 2);
    if (len1 == len2) return true;

    return false;
}


/************************************************************************/
/* External Class Implementation                                        */
/************************************************************************/

bool shapePrepare(SwShape* shape, const Shape* sdata, const SwSize& clip, const Matrix* transform)
{
    if (!shapeGenOutline(shape, sdata, transform)) return false;

    if (!_updateBBox(shape->outline, shape->bbox)) return false;

    if (!_checkValid(shape->outline, shape->bbox, clip)) return false;

    return true;
}


bool shapeGenRle(SwShape* shape, TVG_UNUSED const Shape* sdata, const SwSize& clip, bool antiAlias)
{
    //FIXME: Should we draw it?
    //Case: Stroke Line
    //if (shape.outline->opened) return true;

    //Case A: Fast Track Rectangle Drawing
    if ((shape->rect = _fastTrack(shape->outline))) return true;
    //Case B: Normale Shape RLE Drawing
    if ((shape->rle = rleRender(shape->outline, shape->bbox, clip, antiAlias))) return true;

    return false;
}


void shapeDelOutline(SwShape* shape)
{
    auto outline = shape->outline;
    _delOutline(outline);
    shape->outline = nullptr;
}


void shapeReset(SwShape* shape)
{
    shapeDelOutline(shape);
    rleFree(shape->rle);
    shape->rle = nullptr;
    shape->rect = false;
    _initBBox(shape->bbox);
}


bool shapeGenOutline(SwShape* shape, const Shape* sdata, const Matrix* transform)
{
    const PathCommand* cmds = nullptr;
    auto cmdCnt = sdata->pathCommands(&cmds);

    const Point* pts = nullptr;
    auto ptsCnt = sdata->pathCoords(&pts);

    //No actual shape data
    if (cmdCnt == 0 || ptsCnt == 0) return false;

    //smart reservation
    auto outlinePtsCnt = 0;
    auto outlineCntrsCnt = 0;

    for (uint32_t i = 0; i < cmdCnt; ++i) {
        switch(*(cmds + i)) {
            case PathCommand::Close: {
                ++outlinePtsCnt;
                break;
            }
            case PathCommand::MoveTo: {
                ++outlineCntrsCnt;
                ++outlinePtsCnt;
                break;
            }
            case PathCommand::LineTo: {
                ++outlinePtsCnt;
                break;
            }
            case PathCommand::CubicTo: {
                outlinePtsCnt += 3;
                break;
            }
        }
    }

    ++outlinePtsCnt;    //for close
    ++outlineCntrsCnt;  //for end

    auto outline = shape->outline;
    if (!outline) outline = static_cast<SwOutline*>(calloc(1, sizeof(SwOutline)));
    outline->opened = true;

    _growOutlinePoint(*outline, outlinePtsCnt);
    _growOutlineContour(*outline, outlineCntrsCnt);

    auto closed = false;

    //Generate Outlines
    while (cmdCnt-- > 0) {
        switch(*cmds) {
            case PathCommand::Close: {
                _outlineClose(*outline);
                closed = true;
                break;
            }
            case PathCommand::MoveTo: {
                _outlineMoveTo(*outline, pts, transform);
                ++pts;
                break;
            }
            case PathCommand::LineTo: {
                _outlineLineTo(*outline, pts, transform);
                ++pts;
                break;
            }
            case PathCommand::CubicTo: {
                _outlineCubicTo(*outline, pts, pts + 1, pts + 2, transform);
                pts += 3;
                break;
            }
        }
        ++cmds;
    }

    _outlineEnd(*outline);

    if (closed) outline->opened = false;

    //FIXME:
    //outline->flags = SwOutline::FillRule::Winding;

    shape->outline = outline;

    return true;
}


void shapeFree(SwShape* shape)
{
    shapeDelOutline(shape);
    rleFree(shape->rle);
    shapeDelFill(shape);

    if (shape->stroke) {
        rleFree(shape->strokeRle);
        strokeFree(shape->stroke);
    }
}


void shapeDelStroke(SwShape* shape)
{
    if (!shape->stroke) return;
    rleFree(shape->strokeRle);
    shape->strokeRle = nullptr;
    strokeFree(shape->stroke);
    shape->stroke = nullptr;
}


void shapeResetStroke(SwShape* shape, const Shape* sdata, const Matrix* transform)
{
    if (!shape->stroke) shape->stroke = static_cast<SwStroke*>(calloc(1, sizeof(SwStroke)));
    auto stroke = shape->stroke;
    if (!stroke) return;

    strokeReset(stroke, sdata, transform);

    rleFree(shape->strokeRle);
    shape->strokeRle = nullptr;
}


bool shapeGenStrokeRle(SwShape* shape, const Shape* sdata, const Matrix* transform, const SwSize& clip)
{
    SwOutline* shapeOutline = nullptr;
    SwOutline* strokeOutline = nullptr;
    bool freeOutline = false;
    bool ret = true;

    //Dash Style Stroke
    if (sdata->strokeDash(nullptr) > 0) {
        shapeOutline = _genDashOutline(sdata, transform);
        if (!shapeOutline) return false;
        freeOutline = true;
    //Normal Style stroke
    } else {
        if (!shape->outline) {
            if (!shapeGenOutline(shape, sdata, transform)) return false;
        }
        shapeOutline = shape->outline;
    }

    if (!strokeParseOutline(shape->stroke, *shapeOutline)) {
        ret = false;
        goto fail;
    }

    strokeOutline = strokeExportOutline(shape->stroke);
    if (!strokeOutline) {
        ret = false;
        goto fail;
    }

    SwBBox bbox;
    _updateBBox(strokeOutline, bbox);

    if (!_checkValid(strokeOutline, bbox, clip)) {
        ret = false;
        goto fail;
    }

    shape->strokeRle = rleRender(strokeOutline, bbox, clip, true);

fail:
    if (freeOutline) _delOutline(shapeOutline);
    _delOutline(strokeOutline);

    return ret;
}


bool shapeGenFillColors(SwShape* shape, const Fill* fill, const Matrix* transform, SwSurface* surface, bool ctable)
{
    return fillGenColorTable(shape->fill, fill, transform, surface, ctable);
}


void shapeResetFill(SwShape* shape)
{
    if (!shape->fill) {
        shape->fill = static_cast<SwFill*>(calloc(1, sizeof(SwFill)));
        if (!shape->fill) return;
    }
    fillReset(shape->fill);
}


void shapeDelFill(SwShape* shape)
{
    if (!shape->fill) return;
    fillFree(shape->fill);
    shape->fill = nullptr;
}