'use strict';

const { EventEmitter } = require('events');

let nextItemID = 1;

class TouchBar extends EventEmitter {
  // Bind a touch bar to a window
  static _setOnWindow (touchBar, window) {
    if (window._touchBar != null) {
      window._touchBar._removeFromWindow(window);
    }

    if (touchBar == null) {
      window._setTouchBarItems([]);
      return;
    }

    if (Array.isArray(touchBar)) {
      touchBar = new TouchBar(touchBar);
    }
    touchBar._addToWindow(window);
  }

  constructor (options) {
    super();

    if (options == null) {
      throw new Error('Must specify options object as first argument');
    }

    let { items, escapeItem } = options;

    if (!Array.isArray(items)) {
      items = [];
    }

    this.changeListener = (item) => {
      this.emit('change', item.id, item.type);
    };

    this.windowListeners = {};
    this.items = {};
    this.ordereredItems = [];
    this.escapeItem = escapeItem;

    const registerItem = (item) => {
      this.items[item.id] = item;
      item.on('change', this.changeListener);
      if (item.child instanceof TouchBar) {
        item.child.ordereredItems.forEach(registerItem);
      }
    };

    let hasOtherItemsProxy = false;
    const idSet = new Set();
    items.forEach((item) => {
      if (!(item instanceof TouchBarItem)) {
        throw new Error('Each item must be an instance of TouchBarItem');
      }

      if (item.type === 'other_items_proxy') {
        if (!hasOtherItemsProxy) {
          hasOtherItemsProxy = true;
        } else {
          throw new Error('Must only have one OtherItemsProxy per TouchBar');
        }
      }

      if (!idSet.has(item.id)) {
        idSet.add(item.id);
      } else {
        throw new Error('Cannot add a single instance of TouchBarItem multiple times in a TouchBar');
      }
    });

    // register in separate loop after all items are validated
    for (const item of items) {
      this.ordereredItems.push(item);
      registerItem(item);
    }
  }

  set escapeItem (item) {
    if (item != null && !(item instanceof TouchBarItem)) {
      throw new Error('Escape item must be an instance of TouchBarItem');
    }
    if (this.escapeItem != null) {
      this.escapeItem.removeListener('change', this.changeListener);
    }
    this._escapeItem = item;
    if (this.escapeItem != null) {
      this.escapeItem.on('change', this.changeListener);
    }
    this.emit('escape-item-change', item);
  }

  get escapeItem () {
    return this._escapeItem;
  }

  _addToWindow (window) {
    const { id } = window;

    // Already added to window
    if (Object.prototype.hasOwnProperty.call(this.windowListeners, id)) return;

    window._touchBar = this;

    const changeListener = (itemID) => {
      window._refreshTouchBarItem(itemID);
    };
    this.on('change', changeListener);

    const escapeItemListener = (item) => {
      window._setEscapeTouchBarItem(item != null ? item : {});
    };
    this.on('escape-item-change', escapeItemListener);

    const interactionListener = (event, itemID, details) => {
      let item = this.items[itemID];
      if (item == null && this.escapeItem != null && this.escapeItem.id === itemID) {
        item = this.escapeItem;
      }
      if (item != null && item.onInteraction != null) {
        item.onInteraction(details);
      }
    };
    window.on('-touch-bar-interaction', interactionListener);

    const removeListeners = () => {
      this.removeListener('change', changeListener);
      this.removeListener('escape-item-change', escapeItemListener);
      window.removeListener('-touch-bar-interaction', interactionListener);
      window.removeListener('closed', removeListeners);
      window._touchBar = null;
      delete this.windowListeners[id];
      const unregisterItems = (items) => {
        for (const item of items) {
          item.removeListener('change', this.changeListener);
          if (item.child instanceof TouchBar) {
            unregisterItems(item.child.ordereredItems);
          }
        }
      };
      unregisterItems(this.ordereredItems);
      if (this.escapeItem) {
        this.escapeItem.removeListener('change', this.changeListener);
      }
    };
    window.once('closed', removeListeners);
    this.windowListeners[id] = removeListeners;

    window._setTouchBarItems(this.ordereredItems);
    escapeItemListener(this.escapeItem);
  }

  _removeFromWindow (window) {
    const removeListeners = this.windowListeners[window.id];
    if (removeListeners != null) removeListeners();
  }
}

class TouchBarItem extends EventEmitter {
  constructor () {
    super();
    this._addImmutableProperty('id', `${nextItemID++}`);
    this._parents = [];
  }

  _addImmutableProperty (name, value) {
    Object.defineProperty(this, name, {
      get: function () {
        return value;
      },
      set: function () {
        throw new Error(`Cannot override property ${name}`);
      },
      enumerable: true,
      configurable: false
    });
  }

  _addLiveProperty (name, initialValue) {
    const privateName = `_${name}`;
    this[privateName] = initialValue;
    Object.defineProperty(this, name, {
      get: function () {
        return this[privateName];
      },
      set: function (value) {
        this[privateName] = value;
        this.emit('change', this);
      },
      enumerable: true
    });
  }

  _addParent (item) {
    const existing = this._parents.some(test => test.id === item.id);
    if (!existing) {
      this._parents.push({
        id: item.id,
        type: item.type
      });
    }
  }
}

TouchBar.TouchBarButton = class TouchBarButton extends TouchBarItem {
  constructor (config) {
    super();
    if (config == null) config = {};
    this._addImmutableProperty('type', 'button');
    this._addLiveProperty('label', config.label);
    this._addLiveProperty('accessibilityLabel', config.accessibilityLabel);
    this._addLiveProperty('backgroundColor', config.backgroundColor);
    this._addLiveProperty('icon', config.icon);
    this._addLiveProperty('iconPosition', config.iconPosition);
    this._addLiveProperty('enabled', typeof config.enabled !== 'boolean' ? true : config.enabled);
    if (typeof config.click === 'function') {
      this._addImmutableProperty('onInteraction', () => {
        config.click();
      });
    }
  }
};

TouchBar.TouchBarColorPicker = class TouchBarColorPicker extends TouchBarItem {
  constructor (config) {
    super();
    if (config == null) config = {};
    this._addImmutableProperty('type', 'colorpicker');
    this._addLiveProperty('availableColors', config.availableColors);
    this._addLiveProperty('selectedColor', config.selectedColor);

    if (typeof config.change === 'function') {
      this._addImmutableProperty('onInteraction', (details) => {
        this._selectedColor = details.color;
        config.change(details.color);
      });
    }
  }
};

TouchBar.TouchBarGroup = class TouchBarGroup extends TouchBarItem {
  constructor (config) {
    super();
    if (config == null) config = {};
    this._addImmutableProperty('type', 'group');
    const defaultChild = (config.items instanceof TouchBar) ? config.items : new TouchBar(config.items);
    this._addLiveProperty('child', defaultChild);
    this.child.ordereredItems.forEach((item) => item._addParent(this));
  }
};

TouchBar.TouchBarLabel = class TouchBarLabel extends TouchBarItem {
  constructor (config) {
    super();
    if (config == null) config = {};
    this._addImmutableProperty('type', 'label');
    this._addLiveProperty('label', config.label);
    this._addLiveProperty('accessibilityLabel', config.accessibilityLabel);
    this._addLiveProperty('textColor', config.textColor);
  }
};

TouchBar.TouchBarPopover = class TouchBarPopover extends TouchBarItem {
  constructor (config) {
    super();
    if (config == null) config = {};
    this._addImmutableProperty('type', 'popover');
    this._addLiveProperty('label', config.label);
    this._addLiveProperty('icon', config.icon);
    this._addLiveProperty('showCloseButton', config.showCloseButton);
    const defaultChild = (config.items instanceof TouchBar) ? config.items : new TouchBar(config.items);
    this._addLiveProperty('child', defaultChild);
    this.child.ordereredItems.forEach((item) => item._addParent(this));
  }
};

TouchBar.TouchBarSlider = class TouchBarSlider extends TouchBarItem {
  constructor (config) {
    super();
    if (config == null) config = {};
    this._addImmutableProperty('type', 'slider');
    this._addLiveProperty('label', config.label);
    this._addLiveProperty('minValue', config.minValue);
    this._addLiveProperty('maxValue', config.maxValue);
    this._addLiveProperty('value', config.value);

    if (typeof config.change === 'function') {
      this._addImmutableProperty('onInteraction', (details) => {
        this._value = details.value;
        config.change(details.value);
      });
    }
  }
};

TouchBar.TouchBarSpacer = class TouchBarSpacer extends TouchBarItem {
  constructor (config) {
    super();
    if (config == null) config = {};
    this._addImmutableProperty('type', 'spacer');
    this._addImmutableProperty('size', config.size);
  }
};

TouchBar.TouchBarSegmentedControl = class TouchBarSegmentedControl extends TouchBarItem {
  constructor (config) {
    super();
    if (config == null) config = {};
    this._addImmutableProperty('type', 'segmented_control');
    this._addLiveProperty('segmentStyle', config.segmentStyle);
    this._addLiveProperty('segments', config.segments || []);
    this._addLiveProperty('selectedIndex', config.selectedIndex);
    this._addLiveProperty('mode', config.mode);

    if (typeof config.change === 'function') {
      this._addImmutableProperty('onInteraction', (details) => {
        this._selectedIndex = details.selectedIndex;
        config.change(details.selectedIndex, details.isSelected);
      });
    }
  }
};

TouchBar.TouchBarScrubber = class TouchBarScrubber extends TouchBarItem {
  constructor (config) {
    super();
    if (config == null) config = {};
    let { select, highlight } = config;
    this._addImmutableProperty('type', 'scrubber');
    this._addLiveProperty('items', config.items);
    this._addLiveProperty('selectedStyle', config.selectedStyle || null);
    this._addLiveProperty('overlayStyle', config.overlayStyle || null);
    this._addLiveProperty('showArrowButtons', config.showArrowButtons || false);
    this._addLiveProperty('mode', config.mode || 'free');

    const cont = typeof config.continuous === 'undefined' ? true : config.continuous;
    this._addLiveProperty('continuous', cont);

    if (typeof select === 'function' || typeof highlight === 'function') {
      if (select == null) select = () => {};
      if (highlight == null) highlight = () => {};
      this._addImmutableProperty('onInteraction', (details) => {
        if (details.type === 'select' && typeof select === 'function') {
          select(details.selectedIndex);
        } else if (details.type === 'highlight' && typeof highlight === 'function') {
          highlight(details.highlightedIndex);
        }
      });
    }
  }
};

TouchBar.TouchBarOtherItemsProxy = class TouchBarOtherItemsProxy extends TouchBarItem {
  constructor (config) {
    super();
    this._addImmutableProperty('type', 'other_items_proxy');
  }
};

module.exports = TouchBar;