/**
 * @file 解析cff字形
 * @author mengke01(kekee000@gmail.com)
 */




/**
 * 解析cff字形，返回直线和三次bezier曲线点数组
 * @param  {Array} code  操作码
 * @param  {Object} font  相关联的font对象
 * @param  {number} index glyf索引
 * @return {Object}       glyf对象
 */
function parseCFFCharstring(code, font, index) {
    var c1x;
    var c1y;
    var c2x;
    var c2y;
    var contours = [];
    var contour = [];
    var stack = [];
    var nStems = 0;
    var haveWidth = false;
    var width = font.defaultWidthX;
    var open = false;
    var x = 0;
    var y = 0;

    function lineTo(x, y) {
        contour.push({
            onCurve: true,
            x: x,
            y: y
        });
    }

    function curveTo(c1x, c1y, c2x, c2y, x, y) {
        contour.push({
            x: c1x,
            y: c1y
        });
        contour.push({
            x: c2x,
            y: c2y
        });
        contour.push({
            onCurve: true,
            x: x,
            y: y
        });
    }

    function newContour(x, y) {
        if (open) {
            contours.push(contour);
        }

        contour = [];
        lineTo(x, y);
        open = true;
    }

    function parseStems() {
        var hasWidthArg;
        // The number of stem operators on the stack is always even.
        // If the value is uneven, that means a width is specified.
        hasWidthArg = stack.length % 2 !== 0;
        if (hasWidthArg && !haveWidth) {
            width = stack.shift() + font.nominalWidthX;
        }

        nStems += stack.length >> 1;
        stack.length = 0;
        haveWidth = true;
    }

    function parse(code) {
        var b1;
        var b2;
        var b3;
        var b4;
        var codeIndex;
        var subrCode;
        var jpx;
        var jpy;
        var c3x;
        var c3y;
        var c4x;
        var c4y;

        var i = 0;
        while (i < code.length) {
            var v = code[i];
            i += 1;
            switch (v) {
                case 1: // hstem
                    parseStems();
                    break;
                case 3: // vstem
                    parseStems();
                    break;
                case 4: // vmoveto
                    if (stack.length > 1 && !haveWidth) {
                        width = stack.shift() + font.nominalWidthX;
                        haveWidth = true;
                    }

                    y += stack.pop();
                    newContour(x, y);
                    break;
                case 5: // rlineto
                    while (stack.length > 0) {
                        x += stack.shift();
                        y += stack.shift();
                        lineTo(x, y);
                    }

                    break;
                case 6: // hlineto
                    while (stack.length > 0) {
                        x += stack.shift();
                        lineTo(x, y);
                        if (stack.length === 0) {
                            break;
                        }

                        y += stack.shift();
                        lineTo(x, y);
                    }

                    break;
                case 7: // vlineto
                    while (stack.length > 0) {
                        y += stack.shift();
                        lineTo(x, y);
                        if (stack.length === 0) {
                            break;
                        }

                        x += stack.shift();
                        lineTo(x, y);
                    }

                    break;
                case 8: // rrcurveto
                    while (stack.length > 0) {
                        c1x = x + stack.shift();
                        c1y = y + stack.shift();
                        c2x = c1x + stack.shift();
                        c2y = c1y + stack.shift();
                        x = c2x + stack.shift();
                        y = c2y + stack.shift();
                        curveTo(c1x, c1y, c2x, c2y, x, y);
                    }

                    break;
                case 10: // callsubr
                    codeIndex = stack.pop() + font.subrsBias;
                    subrCode = font.subrs[codeIndex];
                    if (subrCode) {
                        parse(subrCode);
                    }

                    break;
                case 11: // return
                    return;
                case 12: // flex operators
                    v = code[i];
                    i += 1;
                    switch (v) {
                        case 35: // flex
                            // |- dx1 dy1 dx2 dy2 dx3 dy3 dx4 dy4 dx5 dy5 dx6 dy6 fd flex (12 35) |-
                            c1x = x   + stack.shift();    // dx1
                            c1y = y   + stack.shift();    // dy1
                            c2x = c1x + stack.shift();    // dx2
                            c2y = c1y + stack.shift();    // dy2
                            jpx = c2x + stack.shift();    // dx3
                            jpy = c2y + stack.shift();    // dy3
                            c3x = jpx + stack.shift();    // dx4
                            c3y = jpy + stack.shift();    // dy4
                            c4x = c3x + stack.shift();    // dx5
                            c4y = c3y + stack.shift();    // dy5
                            x = c4x + stack.shift();      // dx6
                            y = c4y + stack.shift();      // dy6
                            stack.shift();                // flex depth
                            curveTo(c1x, c1y, c2x, c2y, jpx, jpy);
                            curveTo(c3x, c3y, c4x, c4y, x, y);
                            break;
                        case 34: // hflex
                            // |- dx1 dx2 dy2 dx3 dx4 dx5 dx6 hflex (12 34) |-
                            c1x = x   + stack.shift();    // dx1
                            c1y = y;                      // dy1
                            c2x = c1x + stack.shift();    // dx2
                            c2y = c1y + stack.shift();    // dy2
                            jpx = c2x + stack.shift();    // dx3
                            jpy = c2y;                    // dy3
                            c3x = jpx + stack.shift();    // dx4
                            c3y = c2y;                    // dy4
                            c4x = c3x + stack.shift();    // dx5
                            c4y = y;                      // dy5
                            x = c4x + stack.shift();      // dx6
                            curveTo(c1x, c1y, c2x, c2y, jpx, jpy);
                            curveTo(c3x, c3y, c4x, c4y, x, y);
                            break;
                        case 36: // hflex1
                            // |- dx1 dy1 dx2 dy2 dx3 dx4 dx5 dy5 dx6 hflex1 (12 36) |-
                            c1x = x   + stack.shift();    // dx1
                            c1y = y   + stack.shift();    // dy1
                            c2x = c1x + stack.shift();    // dx2
                            c2y = c1y + stack.shift();    // dy2
                            jpx = c2x + stack.shift();    // dx3
                            jpy = c2y;                    // dy3
                            c3x = jpx + stack.shift();    // dx4
                            c3y = c2y;                    // dy4
                            c4x = c3x + stack.shift();    // dx5
                            c4y = c3y + stack.shift();    // dy5
                            x = c4x + stack.shift();      // dx6
                            curveTo(c1x, c1y, c2x, c2y, jpx, jpy);
                            curveTo(c3x, c3y, c4x, c4y, x, y);
                            break;
                        case 37: // flex1
                            // |- dx1 dy1 dx2 dy2 dx3 dy3 dx4 dy4 dx5 dy5 d6 flex1 (12 37) |-
                            c1x = x   + stack.shift();    // dx1
                            c1y = y   + stack.shift();    // dy1
                            c2x = c1x + stack.shift();    // dx2
                            c2y = c1y + stack.shift();    // dy2
                            jpx = c2x + stack.shift();    // dx3
                            jpy = c2y + stack.shift();    // dy3
                            c3x = jpx + stack.shift();    // dx4
                            c3y = jpy + stack.shift();    // dy4
                            c4x = c3x + stack.shift();    // dx5
                            c4y = c3y + stack.shift();    // dy5
                            if (Math.abs(c4x - x) > Math.abs(c4y - y)) {
                                x = c4x + stack.shift();
                            }
                            else {
                                y = c4y + stack.shift();
                            }

                            curveTo(c1x, c1y, c2x, c2y, jpx, jpy);
                            curveTo(c3x, c3y, c4x, c4y, x, y);
                            break;
                        default:
                            console.warn('Glyph ' + index + ': unknown operator ' + (1200 + v));
                            stack.length = 0;
                    }
                    break;
                case 14: // endchar
                    if (stack.length > 0 && !haveWidth) {
                        width = stack.shift() + font.nominalWidthX;
                        haveWidth = true;
                    }

                    if (open) {
                        contours.push(contour);
                        open = false;
                    }

                    break;
                case 18: // hstemhm
                    parseStems();
                    break;
                case 19: // hintmask
                case 20: // cntrmask
                    parseStems();
                    i += (nStems + 7) >> 3;
                    break;
                case 21: // rmoveto
                    if (stack.length > 2 && !haveWidth) {
                        width = stack.shift() + font.nominalWidthX;
                        haveWidth = true;
                    }

                    y += stack.pop();
                    x += stack.pop();
                    newContour(x, y);
                    break;
                case 22: // hmoveto
                    if (stack.length > 1 && !haveWidth) {
                        width = stack.shift() + font.nominalWidthX;
                        haveWidth = true;
                    }

                    x += stack.pop();
                    newContour(x, y);
                    break;
                case 23: // vstemhm
                    parseStems();
                    break;
                case 24: // rcurveline
                    while (stack.length > 2) {
                        c1x = x + stack.shift();
                        c1y = y + stack.shift();
                        c2x = c1x + stack.shift();
                        c2y = c1y + stack.shift();
                        x = c2x + stack.shift();
                        y = c2y + stack.shift();
                        curveTo(c1x, c1y, c2x, c2y, x, y);
                    }

                    x += stack.shift();
                    y += stack.shift();
                    lineTo(x, y);
                    break;
                case 25: // rlinecurve
                    while (stack.length > 6) {
                        x += stack.shift();
                        y += stack.shift();
                        lineTo(x, y);
                    }

                    c1x = x + stack.shift();
                    c1y = y + stack.shift();
                    c2x = c1x + stack.shift();
                    c2y = c1y + stack.shift();
                    x = c2x + stack.shift();
                    y = c2y + stack.shift();
                    curveTo(c1x, c1y, c2x, c2y, x, y);
                    break;
                case 26: // vvcurveto
                    if (stack.length % 2) {
                        x += stack.shift();
                    }

                    while (stack.length > 0) {
                        c1x = x;
                        c1y = y + stack.shift();
                        c2x = c1x + stack.shift();
                        c2y = c1y + stack.shift();
                        x = c2x;
                        y = c2y + stack.shift();
                        curveTo(c1x, c1y, c2x, c2y, x, y);
                    }

                    break;
                case 27: // hhcurveto
                    if (stack.length % 2) {
                        y += stack.shift();
                    }

                    while (stack.length > 0) {
                        c1x = x + stack.shift();
                        c1y = y;
                        c2x = c1x + stack.shift();
                        c2y = c1y + stack.shift();
                        x = c2x + stack.shift();
                        y = c2y;
                        curveTo(c1x, c1y, c2x, c2y, x, y);
                    }

                    break;
                case 28: // shortint
                    b1 = code[i];
                    b2 = code[i + 1];
                    stack.push(((b1 << 24) | (b2 << 16)) >> 16);
                    i += 2;
                    break;
                case 29: // callgsubr
                    codeIndex = stack.pop() + font.gsubrsBias;
                    subrCode = font.gsubrs[codeIndex];
                    if (subrCode) {
                        parse(subrCode);
                    }

                    break;
                case 30: // vhcurveto
                    while (stack.length > 0) {
                        c1x = x;
                        c1y = y + stack.shift();
                        c2x = c1x + stack.shift();
                        c2y = c1y + stack.shift();
                        x = c2x + stack.shift();
                        y = c2y + (stack.length === 1 ? stack.shift() : 0);
                        curveTo(c1x, c1y, c2x, c2y, x, y);
                        if (stack.length === 0) {
                            break;
                        }

                        c1x = x + stack.shift();
                        c1y = y;
                        c2x = c1x + stack.shift();
                        c2y = c1y + stack.shift();
                        y = c2y + stack.shift();
                        x = c2x + (stack.length === 1 ? stack.shift() : 0);
                        curveTo(c1x, c1y, c2x, c2y, x, y);
                    }

                    break;
                case 31: // hvcurveto
                    while (stack.length > 0) {
                        c1x = x + stack.shift();
                        c1y = y;
                        c2x = c1x + stack.shift();
                        c2y = c1y + stack.shift();
                        y = c2y + stack.shift();
                        x = c2x + (stack.length === 1 ? stack.shift() : 0);
                        curveTo(c1x, c1y, c2x, c2y, x, y);
                        if (stack.length === 0) {
                            break;
                        }

                        c1x = x;
                        c1y = y + stack.shift();
                        c2x = c1x + stack.shift();
                        c2y = c1y + stack.shift();
                        x = c2x + stack.shift();
                        y = c2y + (stack.length === 1 ? stack.shift() : 0);
                        curveTo(c1x, c1y, c2x, c2y, x, y);
                    }

                    break;
                default:
                    if (v < 32) {
                        console.warn('Glyph ' + index + ': unknown operator ' + v);
                    }
                    else if (v < 247) {
                        stack.push(v - 139);
                    }
                    else if (v < 251) {
                        b1 = code[i];
                        i += 1;
                        stack.push((v - 247) * 256 + b1 + 108);
                    }
                    else if (v < 255) {
                        b1 = code[i];
                        i += 1;
                        stack.push(-(v - 251) * 256 - b1 - 108);
                    }
                    else {
                        b1 = code[i];
                        b2 = code[i + 1];
                        b3 = code[i + 2];
                        b4 = code[i + 3];
                        i += 4;
                        stack.push(((b1 << 24) | (b2 << 16) | (b3 << 8) | b4) / 65536);
                    }
            }
        }
    }

    parse(code);
    var glyf = {

        // 移除重复的起点和终点
        contours: contours.map(function (contour) {
            var last = contour.length - 1;
            if (contour[0].x === contour[last].x && contour[0].y === contour[last].y) {
                contour.splice(last, 1);
            }
            return contour;
        }),

        advanceWidth: width
    };
    return glyf;
}

module.exports = parseCFFCharstring;
    
