/**
 *公章
 *
 * @param {String} id
 * @param {Object} option
 */
function PSeal(id, option) {
  // 获取 canvas
  this.canvas = document.querySelector(id);
  // 获取 ctx
  this.ctx = this.canvas.getContext('2d');
  // 对 option 进行处理，如果没有传入就为空对象
  option = option || {};
}

PSeal.prototype.saveSealImg = function saveSealImg() {
  return this.canvas.toDataURL();
};

/**
 *公司公章
 *
 * @param {String} id
 * @param {Object} option
 */
function Seal(id, option) {
  PSeal.call(this, id, option);
  /* 用户可配置项 */

  // 印章半径
  this.radius = option.radius || 75;
  // 印章颜色
  this.color = option.color || '#e60021';
  // 字体
  this.fontFamily = option.fontFamily || '宋体';
  // 公司名称
  this.companyName = option.companyName || '青岛国富金融资产交易中心';
  // 印章类型名称
  this.typeName = option.typeName;
  // 是否有内边框线
  this.hasInnerLine = option.hasInnerLine;
  // 防伪码
  this.securityCode = option.securityCode;

  /* 默认根据半径进行设置 */

  // 边框线的宽度
  this.lineWidth = 4 / 75 * this.radius;
  // 文字与外边框线的距离
  this.lineTextGap = 0.73;
  // 公司名称字体大小
  this.companyNameFontSize = 17 / 75 * this.radius;
  // 印章类型名称字体大小
  this.typeNameFontSize = 11 / 75 * this.radius;
  // 防伪码字体大小
  this.securityCodeFontSize = 0.12 * this.radius;
  // 内边框线的宽度
  this.innerLineWidth = 1 / 75 * this.radius;
  // 字与字之间相差的弧度
  this.step = 0.32;
  // 根据公司名称有多少个字，控制第一个字的起始位置
  this.aStartPos = [0, -0.15, -0.31, -0.5, -0.63, -0.83, -0.95, -1.12, -1.27, -1.44, -1.61, -1.77, -1.93, -2.1, -2.23, -2.4, -2.57, -2.73, -2.89];
  // 起始位置的index
  this.startIndex = this.companyName.length - 1;
  // 起始位置
  this.startPos = this.aStartPos[this.startIndex];

  // 初始化
  this._init();
}

Seal.prototype = Object.create(PSeal.prototype);

Seal.prototype.constructor = Seal;

Seal.prototype._init = function _init() {
  this.canvas.width = this.canvas.height = this.radius * 2;
  this.ctx.clearRect(0, 0, this.canvas.width, this.canvas.height);
  this._drawOuterLine();
  if (this.hasInnerLine) {
    this._drawInnerLine();
  }
  this._drawStar();
  if (this.companyName) {
    this._drawCompanyName();
  }
  if (this.typeName) {
    this._drawTypeName();
  }
  if (this.securityCode) {
    this._drawSecurityCode();
  }
};

Seal.prototype._drawOuterLine = function _drawOuterLine() {
  this.ctx.save();
  this.ctx.strokeStyle = this.color;
  this.ctx.lineWidth = this.lineWidth;
  this.ctx.beginPath();
  this.ctx.arc(this.radius, this.radius, this.radius - this.lineWidth, 0, Math.PI * 2, true);
  this.ctx.stroke();
  this.ctx.restore();
};

Seal.prototype._drawInnerLine = function _drawInnerLine() {
  this.ctx.save();
  this.ctx.strokeStyle = this.color;
  this.ctx.lineWidth = this.innerLineWidth;
  this.ctx.beginPath();
  this.ctx.arc(this.radius, this.radius, this.radius - this.lineWidth - this.radius / 15, 0, Math.PI * 2, true);
  this.ctx.stroke();
  this.ctx.restore();
};

Seal.prototype._drawStar = function _drawStar() {
  var R = this.radius,
    r = R / 3,
    c = 360 / 5 * Math.PI / 180,
    d = c / 2,
    e = d / 2,
    l = r * Math.sin(e) / Math.sin(d + e),
    lsd = l * Math.sin(d),
    lcd = l * Math.cos(d),
    lsc = l * Math.sin(c),
    lcc = l * Math.cos(c),
    rsc = r * Math.sin(c),
    rcc = r * Math.cos(c),
    rsd = r * Math.sin(d),
    rcd = r * Math.cos(d),
    p0 = [R, 2 / 3 * R],
    p1 = [R + lsd, R - lcd],
    p2 = [R + rsc, R - rcc],
    p3 = [R + lsc, R + lcc],
    p4 = [R + rsd, R + rcd],
    p5 = [R, R + l],
    p6 = [R - rsd, R + rcd],
    p7 = [R - lsc, R + lcc],
    p8 = [R - rsc, R - rcc],
    p9 = [R - lsd, R - lcd],
    aPs = [p0, p1, p2, p3, p4, p5, p6, p7, p8, p9];
  this.ctx.save();
  this.ctx.fillStyle = this.color;
  this.ctx.beginPath();
  aPs.forEach(function (item) {
    this.ctx.lineTo(item[0], item[1]);
  }, this)
  // for (var i = 0; i < aPs.length; i++) {
  //   var item = aPs[i];
  //   this.ctx.lineTo(item[0], item[1]);
  // }
  this.ctx.closePath();
  this.ctx.fill();
  this.ctx.restore();
};

Seal.prototype._drawCompanyName = function _drawCompanyName() {
  if (this.companyName.length > 19) {
    throw new RangeError('公司名称最多只能为19个字符！');
  }
  this._drawText(this.companyName, this.companyNameFontSize, false, false);
};

Seal.prototype._drawText = function _drawText(text, fontSize, isTypeName, isSecurityCode) {
  var i, letter;
  this.ctx.save();
  this.ctx.fillStyle = this.color;
  this.ctx.font = 'normal normal bold ' + fontSize + 'px ' + this.fontFamily;
  this.ctx.textBaseline = 'middle';
  if (isTypeName) {
    this.ctx.textAlign = 'center';
  } else {
    this.ctx.textAlign = 'left';
  }
  this.ctx.translate(this.radius, this.radius);
  if (isTypeName) {
    this.ctx.fillText(text, 0, this.radius / 2);
  } else {
    for (i = 0; i < text.length; i++) {
      letter = text[i];
      if (isSecurityCode) {
        this._drawLetter(letter, 0.57 - i * 0.1, -this.securityCodeFontSize / 2, this.radius * 0.8);
      } else {
        this._drawLetter(letter, this.startPos + i * this.step, -fontSize / 2, -this.radius * this.lineTextGap);
      }
    }
  }
  this.ctx.restore();
};

Seal.prototype._drawLetter = function _drawLetter(letter, angle, x, y) {
  this.ctx.save();
  this.ctx.rotate(angle);
  this.ctx.fillText(letter, x, y);
  this.ctx.restore();
};

Seal.prototype._drawTypeName = function _drawTypeName() {
  if (typeof this.typeName !== 'string') {
    throw new TypeError('印章类型名称只能为字符串！');
  }
  this._drawText(this.typeName, this.typeNameFontSize, true, false);
};

Seal.prototype._drawSecurityCode = function _drawSecurityCode() {
  if (typeof this.securityCode !== 'string') {
    throw new TypeError('防伪码只能为字符串！');
  }
  if (this.securityCode.length !== 13) {
    throw new RangeError('防伪码只能为13位！');
  }
  this._drawText(this.securityCode, this.securityCodeFontSize, false, true);
};


export default Seal;