/**
 * @license
 * Visual Blocks Editor
 *
 * Copyright 2012 Google Inc.
 * https://developers.google.com/blockly/
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * @fileoverview Text input field.
 * @author fraser@google.com (Neil Fraser)
 */
'use strict';

goog.provide('Blockly.FieldTextInput');

goog.require('Blockly.Field');
goog.require('Blockly.Msg');
goog.require('goog.asserts');
goog.require('goog.dom');
goog.require('goog.userAgent');


/**
 * Class for an editable text field.
 * @param {string} text The initial content of the field.
 * @param {Function=} opt_changeHandler An optional function that is called
 *     to validate any constraints on what the user entered.  Takes the new
 *     text as an argument and returns either the accepted text, a replacement
 *     text, or null to abort the change.
 * @extends {Blockly.Field}
 * @constructor
 */
Blockly.FieldTextInput = function(text, opt_changeHandler) {
  Blockly.FieldTextInput.superClass_.constructor.call(this, text);
  this.setChangeHandler(opt_changeHandler);
};
goog.inherits(Blockly.FieldTextInput, Blockly.Field);

/**
 * Clone this FieldTextInput.
 * @return {!Blockly.FieldTextInput} The result of calling the constructor again
 *   with the current values of the arguments used during construction.
 */
Blockly.FieldTextInput.prototype.clone = function() {
  return new Blockly.FieldTextInput(this.getText(), this.changeHandler_);
};

/**
 * Mouse cursor style when over the hotspot that initiates the editor.
 */
Blockly.FieldTextInput.prototype.CURSOR = 'text';

/**
 * Allow browser to spellcheck this field.
 * @private
 */
Blockly.FieldTextInput.prototype.spellcheck_ = true;

/**
 * Close the input widget if this input is being deleted.
 */
Blockly.FieldTextInput.prototype.dispose = function() {
  Blockly.WidgetDiv.hideIfOwner(this);
  Blockly.FieldTextInput.superClass_.dispose.call(this);
};

/**
 * Set the text in this field.
 * @param {?string} text New text.
 * @override
 */
Blockly.FieldTextInput.prototype.setText = function(text) {
  if (text === null) {
    // No change if null.
    return;
  }
  if (this.sourceBlock_ && this.changeHandler_) {
    var validated = this.changeHandler_(text);
    // If the new text is invalid, validation returns null.
    // In this case we still want to display the illegal result.
    if (validated !== null && validated !== undefined) {
      text = validated;
    }
  }
  Blockly.Field.prototype.setText.call(this, text);
};

/**
 * Set whether this field is spellchecked by the browser.
 * @param {boolean} check True if checked.
 */
Blockly.FieldTextInput.prototype.setSpellcheck = function(check) {
  this.spellcheck_ = check;
};

/**
 * Show the inline free-text editor on top of the text.
 * @param {boolean=} opt_quietInput True if editor should be created without
 *     focus.  Defaults to false.
 * @private
 */
Blockly.FieldTextInput.prototype.showEditor_ = function(opt_quietInput) {
  var quietInput = opt_quietInput || false;
  if (!quietInput && (goog.userAgent.MOBILE || goog.userAgent.ANDROID ||
                      goog.userAgent.IPAD)) {
    // Mobile browsers have issues with in-line textareas (focus & keyboards).
    var newValue = window.prompt(Blockly.Msg.CHANGE_VALUE_TITLE, this.text_);
    if (this.sourceBlock_ && this.changeHandler_) {
      var override = this.changeHandler_(newValue);
      if (override !== undefined) {
        newValue = override;
      }
    }
    if (newValue !== null) {
      this.setText(newValue);
    }
    return;
  }

  Blockly.WidgetDiv.show(this, this.sourceBlock_.RTL, this.widgetDispose_());
  var div = Blockly.WidgetDiv.DIV;
  // Create the input.
  var htmlInput = goog.dom.createDom('input', 'blocklyHtmlInput');
  htmlInput.setAttribute('spellcheck', this.spellcheck_);
  Blockly.FieldTextInput.htmlInput_ = htmlInput;
  div.appendChild(htmlInput);

  htmlInput.value = htmlInput.defaultValue = this.text_;
  htmlInput.oldValue_ = null;
  this.validate_();
  this.resizeEditor_();
  if (!quietInput) {
    htmlInput.focus();
    htmlInput.select();
  }

  // Bind to keydown -- trap Enter without IME and Esc to hide.
  htmlInput.onKeyDownWrapper_ =
      Blockly.bindEvent_(htmlInput, 'keydown', this, this.onHtmlInputKeyDown_);
  // Bind to keyup -- trap Enter; resize after every keystroke.
  htmlInput.onKeyUpWrapper_ =
      Blockly.bindEvent_(htmlInput, 'keyup', this, this.onHtmlInputChange_);
  // Bind to keyPress -- repeatedly resize when holding down a key.
  htmlInput.onKeyPressWrapper_ =
      Blockly.bindEvent_(htmlInput, 'keypress', this, this.onHtmlInputChange_);
  var workspaceSvg = this.sourceBlock_.workspace.getCanvas();
  htmlInput.onWorkspaceChangeWrapper_ =
      Blockly.bindEvent_(workspaceSvg, 'blocklyWorkspaceChange', this,
      this.resizeEditor_);
};

/**
 * Handle key down to the editor.
 * @param {!Event} e Keyboard event.
 * @private
 */
Blockly.FieldTextInput.prototype.onHtmlInputKeyDown_ = function(e) {
  var htmlInput = Blockly.FieldTextInput.htmlInput_;
  var enterKey = 13, escKey = 27;
  if (e.keyCode == enterKey) {
    Blockly.WidgetDiv.hide();
  } else if (e.keyCode == escKey) {
    this.setText(htmlInput.defaultValue);
    Blockly.WidgetDiv.hide();
  }
};

/**
 * Handle a change to the editor.
 * @param {!Event} e Keyboard event.
 * @private
 */
Blockly.FieldTextInput.prototype.onHtmlInputChange_ = function(e) {
  var htmlInput = Blockly.FieldTextInput.htmlInput_;
  var escKey = 27;
  if (e.keyCode != escKey) {
    // Update source block.
    var text = htmlInput.value;
    if (text !== htmlInput.oldValue_) {
      htmlInput.oldValue_ = text;
      this.setText(text);
      this.validate_();
    } else if (goog.userAgent.WEBKIT) {
      // Cursor key.  Render the source block to show the caret moving.
      // Chrome only (version 26, OS X).
      this.sourceBlock_.render();
    }
  }
};

/**
 * Check to see if the contents of the editor validates.
 * Style the editor accordingly.
 * @private
 */
Blockly.FieldTextInput.prototype.validate_ = function() {
  var valid = true;
  goog.asserts.assertObject(Blockly.FieldTextInput.htmlInput_);
  var htmlInput = /** @type {!Element} */ (Blockly.FieldTextInput.htmlInput_);
  if (this.sourceBlock_ && this.changeHandler_) {
    valid = this.changeHandler_(htmlInput.value);
  }
  if (valid === null) {
    Blockly.addClass_(htmlInput, 'blocklyInvalidInput');
  } else {
    Blockly.removeClass_(htmlInput, 'blocklyInvalidInput');
  }
};

/**
 * Resize the editor and the underlying block to fit the text.
 * @private
 */
Blockly.FieldTextInput.prototype.resizeEditor_ = function() {
  var div = Blockly.WidgetDiv.DIV;
  var bBox = this.fieldGroup_.getBBox();
  div.style.width = bBox.width + 'px';
  var xy = this.getAbsoluteXY_();
  // In RTL mode block fields and LTR input fields the left edge moves,
  // whereas the right edge is fixed.  Reposition the editor.
  if (this.sourceBlock_.RTL) {
    var borderBBox = this.borderRect_.getBBox();
    xy.x += borderBBox.width;
    xy.x -= div.offsetWidth;
  }
  // Shift by a few pixels to line up exactly.
  xy.y += 1;
  if (goog.userAgent.WEBKIT) {
    xy.y -= 3;
  }
  div.style.left = xy.x + 'px';
  div.style.top = xy.y + 'px';
};

/**
 * Close the editor, save the results, and dispose of the editable
 * text field's elements.
 * @return {!Function} Closure to call on destruction of the WidgetDiv.
 * @private
 */
Blockly.FieldTextInput.prototype.widgetDispose_ = function() {
  var thisField = this;
  return function() {
    var htmlInput = Blockly.FieldTextInput.htmlInput_;
    // Save the edit (if it validates).
    var text = htmlInput.value;
    if (thisField.sourceBlock_ && thisField.changeHandler_) {
      var text1 = thisField.changeHandler_(text);
      if (text1 === null) {
        // Invalid edit.
        text = htmlInput.defaultValue;
      } else if (text1 !== undefined) {
        // Change handler has changed the text.
        text = text1;
      }
    }
    thisField.setText(text);
    thisField.sourceBlock_.rendered && thisField.sourceBlock_.render();
    Blockly.unbindEvent_(htmlInput.onKeyDownWrapper_);
    Blockly.unbindEvent_(htmlInput.onKeyUpWrapper_);
    Blockly.unbindEvent_(htmlInput.onKeyPressWrapper_);
    Blockly.unbindEvent_(htmlInput.onWorkspaceChangeWrapper_);
    Blockly.FieldTextInput.htmlInput_ = null;
    // Delete the width property.
    Blockly.WidgetDiv.DIV.style.width = 'auto';
  };
};

/**
 * Ensure that only a number may be entered.
 * @param {string} text The user's text.
 * @return {?string} A string representing a valid number, or null if invalid.
 */
Blockly.FieldTextInput.numberValidator = function(text) {
  if (text === null) {
    return null;
  }
  text = String(text);
  // TODO: Handle cases like 'ten', '1.203,14', etc.
  // 'O' is sometimes mistaken for '0' by inexperienced users.
  text = text.replace(/O/ig, '0');
  // Strip out thousands separators.
  text = text.replace(/,/g, '');
  var n = parseFloat(text || 0);
  return isNaN(n) ? null : String(n);
};

/**
 * Ensure that only a nonnegative integer may be entered.
 * @param {string} text The user's text.
 * @return {?string} A string representing a valid int, or null if invalid.
 */
Blockly.FieldTextInput.nonnegativeIntegerValidator = function(text) {
  var n = Blockly.FieldTextInput.numberValidator(text);
  if (n) {
    n = String(Math.max(0, Math.floor(n)));
  }
  return n;
};
