/** 三角函数计算 */
function JTriangle(beg, end) {
    this.init(beg, end);
}
JTriangle.prototype = {
    constructor: JTriangle,
    beg: null,
    end: null,
    abspowx: 0,
    abspowy: 0,
    abspowz: 0,
    drictx: 0,
    dricty: 0,
    drict: 0,

    init (beg, end) {
        this.beg = beg;
        this.end = end;
        this.abspowx = Math.pow(this.end.x - this.beg.x, 2);
        this.abspowy = Math.pow(this.end.y - this.beg.y, 2);
        this.abspowz = this.abspowx + this.abspowy;
        this.absx = Math.abs(this.end.x - this.beg.x);
        this.absy = Math.abs(this.end.y - this.beg.y);
        this.absz = Math.sqrt(Math.pow(this.end.x - this.beg.x, 2), Math.pow(this.end.y - this.beg.y, 2));
        this.drictx = this.end.x > this.beg.x ? 1 : -1;
        this.dricty = this.end.y > this.beg.y ? 1 : -1;
        this.drict = this.drictx * this.dricty;
        this.diff_x = end.x - beg.x;
        this.diff_y = end.y - beg.y;
    },
    getRotation () {
        return Math.atan(this.diff_y / this.diff_x);
    },
    getAngle () {
        return 360 * Math.atan(this.diff_y / this.diff_x) / (2 * Math.PI);
    },
    getCos (n) {
        return this.drictx * Math.sqrt(Math.pow(n, 2) * this.abspowx / this.abspowz);
    },
    getSin (n) {
        return this.dricty * Math.sqrt(Math.pow(n, 2) * this.abspowy / this.abspowz);
    },
    getAbsCos(n) {
        return Math.sqrt(Math.pow(n, 2) * this.abspowx / this.abspowz);
    },
    getAbsSin(n) {
        return Math.sqrt(Math.pow(n, 2) * this.abspowy / this.abspowz);
    },
    getCosRate () {
        return Math.sqrt(this.abspowx / this.abspowz);
    },
    getSinRate () {
        return Math.sqrt(this.abspowy / this.abspowz);
    },
    getTanRate () {
        var diff_x = this.end.x - this.beg.x;
        var diff_y = this.end.y - this.beg.y;
        return Math.abs(diff_y / diff_x);
    },
    getCotRate () {
        var diff_x = this.end.x - this.beg.x;
        var diff_y = this.end.y - this.beg.y;
        return Math.abs(diff_x / diff_y);
    },
    middlePoint () {
        return {
            x: Math.min(this.end.x, this.beg.x) + Math.abs(this.end.x - this.beg.x) / 2,
            y: Math.min(this.end.y, this.beg.y) + Math.abs(this.end.y - this.beg.y) / 2
        };
    }
};

export default JTriangle;