/**
 * @license
 * Copyright (C) 2016 The Android Open Source Project
 *
 * 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.
 */
(function() {
  'use strict';

  const AWAIT_MAX_ITERS = 10;
  const AWAIT_STEP = 5;

  Polymer({
    is: 'gr-editable-label',

    /**
     * Fired when the value is changed.
     *
     * @event changed
     */

    properties: {
      labelText: String,
      editing: {
        type: Boolean,
        value: false,
      },
      value: {
        type: String,
        notify: true,
        value: '',
        observer: '_updateTitle',
      },
      placeholder: {
        type: String,
        value: '',
      },
      readOnly: {
        type: Boolean,
        value: false,
      },
      uppercase: {
        type: Boolean,
        reflectToAttribute: true,
        value: false,
      },
      maxLength: Number,
      _inputText: String,
      // This is used to push the iron-input element up on the page, so
      // the input is placed in approximately the same position as the
      // trigger.
      _verticalOffset: {
        type: Number,
        readOnly: true,
        value: -30,
      },
    },

    behaviors: [
      Gerrit.KeyboardShortcutBehavior,
    ],

    keyBindings: {
      enter: '_handleEnter',
      esc: '_handleEsc',
    },

    hostAttributes: {
      tabindex: '0',
    },

    _usePlaceholder(value, placeholder) {
      return (!value || !value.length) && placeholder;
    },

    _computeLabel(value, placeholder) {
      if (this._usePlaceholder(value, placeholder)) {
        return placeholder;
      }
      return value;
    },

    _showDropdown() {
      if (this.readOnly || this.editing) { return; }
      return this._open().then(() => {
        this.$.input.$.input.focus();
        if (!this.$.input.value) { return; }
        this.$.input.$.input.setSelectionRange(0, this.$.input.value.length);
      });
    },

    open() {
      return this._open().then(() => {
        this.$.input.$.input.focus();
      });
    },

    _open(...args) {
      this.$.dropdown.open();
      this._inputText = this.value;
      this.editing = true;

      return new Promise(resolve => {
        Polymer.IronOverlayBehaviorImpl.open.apply(this.$.dropdown, args);
        this._awaitOpen(resolve);
      });
    },

    /**
     * NOTE: (wyatta) Slightly hacky way to listen to the overlay actually
     * opening. Eventually replace with a direct way to listen to the overlay.
     */
    _awaitOpen(fn) {
      let iters = 0;
      const step = () => {
        this.async(() => {
          if (this.$.dropdown.style.display !== 'none') {
            fn.call(this);
          } else if (iters++ < AWAIT_MAX_ITERS) {
            step.call(this);
          }
        }, AWAIT_STEP);
      };
      step.call(this);
    },

    _id() {
      return this.getAttribute('id') || 'global';
    },

    _save() {
      if (!this.editing) { return; }
      this.$.dropdown.close();
      this.value = this._inputText;
      this.editing = false;
      this.fire('changed', this.value);
    },

    _cancel() {
      if (!this.editing) { return; }
      this.$.dropdown.close();
      this.editing = false;
      this._inputText = this.value;
    },

    /**
     * @suppress {checkTypes}
     * Closure doesn't think 'e' is an Event.
     * TODO(beckysiegel) figure out why.
     */
    _handleEnter(e) {
      e = this.getKeyboardEvent(e);
      const target = Polymer.dom(e).rootTarget;
      if (target === this.$.input.$.input) {
        e.preventDefault();
        this._save();
      }
    },

    /**
     * @suppress {checkTypes}
     * Closure doesn't think 'e' is an Event.
     * TODO(beckysiegel) figure out why.
     */
    _handleEsc(e) {
      e = this.getKeyboardEvent(e);
      const target = Polymer.dom(e).rootTarget;
      if (target === this.$.input.$.input) {
        e.preventDefault();
        this._cancel();
      }
    },

    _computeLabelClass(readOnly, value, placeholder) {
      const classes = [];
      if (!readOnly) { classes.push('editable'); }
      if (this._usePlaceholder(value, placeholder)) {
        classes.push('placeholder');
      }
      return classes.join(' ');
    },

    _updateTitle(value) {
      this.setAttribute('title', this._computeLabel(value, this.placeholder));
    },
  });
})();