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// Copyright 2012 The Closure Library Authors. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//      http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS-IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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/**
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 * @fileoverview A one dimensional linear interpolator.
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 *
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 */
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goog.provide('goog.math.interpolator.Linear1');
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goog.require('goog.array');
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goog.require('goog.asserts');
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goog.require('goog.math');
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goog.require('goog.math.interpolator.Interpolator1');
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/**
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 * A one dimensional linear interpolator.
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 * @implements {goog.math.interpolator.Interpolator1}
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 * @constructor
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 * @final
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 */
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goog.math.interpolator.Linear1 = function() {
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  /**
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   * The abscissa of the data points.
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   * @type {!Array<number>}
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   * @private
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   */
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  this.x_ = [];
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  /**
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   * The ordinate of the data points.
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   * @type {!Array<number>}
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   * @private
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   */
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  this.y_ = [];
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};
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/** @override */
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goog.math.interpolator.Linear1.prototype.setData = function(x, y) {
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  goog.asserts.assert(
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      x.length == y.length,
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      'input arrays to setData should have the same length');
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  if (x.length == 1) {
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    this.x_ = [x[0], x[0] + 1];
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    this.y_ = [y[0], y[0]];
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  } else {
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    this.x_ = x.slice();
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    this.y_ = y.slice();
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  }
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};
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/** @override */
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goog.math.interpolator.Linear1.prototype.interpolate = function(x) {
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  var pos = goog.array.binarySearch(this.x_, x);
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  if (pos < 0) {
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    pos = -pos - 2;
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  }
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  pos = goog.math.clamp(pos, 0, this.x_.length - 2);
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  var progress = (x - this.x_[pos]) / (this.x_[pos + 1] - this.x_[pos]);
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  return goog.math.lerp(this.y_[pos], this.y_[pos + 1], progress);
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};
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/** @override */
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goog.math.interpolator.Linear1.prototype.getInverse = function() {
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  var interpolator = new goog.math.interpolator.Linear1();
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  interpolator.setData(this.y_, this.x_);
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  return interpolator;
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};
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