import defaultValue from "../../Core/defaultValue.js";
import defined from "../../Core/defined.js";
import DeveloperError from "../../Core/DeveloperError.js";
import EllipsoidTerrainProvider from "../../Core/EllipsoidTerrainProvider.js";
import knockout from "../../ThirdParty/knockout.js";
import createCommand from "../createCommand.js";

/**
 * The view model for {@link BaseLayerPicker}.
 * @alias BaseLayerPickerViewModel
 * @constructor
 *
 * @param {Object} options Object with the following properties:
 * @param {Globe} options.globe The Globe to use.
 * @param {ProviderViewModel[]} [options.imageryProviderViewModels=[]] The array of ProviderViewModel instances to use for imagery.
 * @param {ProviderViewModel} [options.selectedImageryProviderViewModel] The view model for the current base imagery layer, if not supplied the first available imagery layer is used.
 * @param {ProviderViewModel[]} [options.terrainProviderViewModels=[]] The array of ProviderViewModel instances to use for terrain.
 * @param {ProviderViewModel} [options.selectedTerrainProviderViewModel] The view model for the current base terrain layer, if not supplied the first available terrain layer is used.
 *
 * @exception {DeveloperError} imageryProviderViewModels must be an array.
 * @exception {DeveloperError} terrainProviderViewModels must be an array.
 */
function BaseLayerPickerViewModel(options) {
  options = defaultValue(options, defaultValue.EMPTY_OBJECT);

  const globe = options.globe;
  const imageryProviderViewModels = defaultValue(
    options.imageryProviderViewModels,
    []
  );
  const terrainProviderViewModels = defaultValue(
    options.terrainProviderViewModels,
    []
  );

  //>>includeStart('debug', pragmas.debug);
  if (!defined(globe)) {
    throw new DeveloperError("globe is required");
  }
  //>>includeEnd('debug');

  this._globe = globe;

  /**
   * Gets or sets an array of ProviderViewModel instances available for imagery selection.
   * This property is observable.
   * @type {ProviderViewModel[]}
   */
  this.imageryProviderViewModels = imageryProviderViewModels.slice(0);

  /**
   * Gets or sets an array of ProviderViewModel instances available for terrain selection.
   * This property is observable.
   * @type {ProviderViewModel[]}
   */
  this.terrainProviderViewModels = terrainProviderViewModels.slice(0);

  /**
   * Gets or sets whether the imagery selection drop-down is currently visible.
   * @type {Boolean}
   * @default false
   */
  this.dropDownVisible = false;

  knockout.track(this, [
    "imageryProviderViewModels",
    "terrainProviderViewModels",
    "dropDownVisible",
  ]);

  const imageryObservable = knockout.getObservable(
    this,
    "imageryProviderViewModels"
  );
  const imageryProviders = knockout.pureComputed(function () {
    const providers = imageryObservable();
    const categories = {};
    let i;
    for (i = 0; i < providers.length; i++) {
      const provider = providers[i];
      const category = provider.category;
      if (defined(categories[category])) {
        categories[category].push(provider);
      } else {
        categories[category] = [provider];
      }
    }
    const allCategoryNames = Object.keys(categories);

    const result = [];
    for (i = 0; i < allCategoryNames.length; i++) {
      const name = allCategoryNames[i];
      result.push({
        name: name,
        providers: categories[name],
      });
    }
    return result;
  });
  this._imageryProviders = imageryProviders;

  const terrainObservable = knockout.getObservable(
    this,
    "terrainProviderViewModels"
  );
  const terrainProviders = knockout.pureComputed(function () {
    const providers = terrainObservable();
    const categories = {};
    let i;
    for (i = 0; i < providers.length; i++) {
      const provider = providers[i];
      const category = provider.category;
      if (defined(categories[category])) {
        categories[category].push(provider);
      } else {
        categories[category] = [provider];
      }
    }
    const allCategoryNames = Object.keys(categories);

    const result = [];
    for (i = 0; i < allCategoryNames.length; i++) {
      const name = allCategoryNames[i];
      result.push({
        name: name,
        providers: categories[name],
      });
    }
    return result;
  });
  this._terrainProviders = terrainProviders;

  /**
   * Gets the button tooltip.  This property is observable.
   * @type {String}
   */
  this.buttonTooltip = undefined;
  knockout.defineProperty(this, "buttonTooltip", function () {
    const selectedImagery = this.selectedImagery;
    const selectedTerrain = this.selectedTerrain;

    const imageryTip = defined(selectedImagery)
      ? selectedImagery.name
      : undefined;
    const terrainTip = defined(selectedTerrain)
      ? selectedTerrain.name
      : undefined;

    if (defined(imageryTip) && defined(terrainTip)) {
      return `${imageryTip}\n${terrainTip}`;
    } else if (defined(imageryTip)) {
      return imageryTip;
    }
    return terrainTip;
  });

  /**
   * Gets the button background image.  This property is observable.
   * @type {String}
   */
  this.buttonImageUrl = undefined;
  knockout.defineProperty(this, "buttonImageUrl", function () {
    const selectedImagery = this.selectedImagery;
    if (defined(selectedImagery)) {
      return selectedImagery.iconUrl;
    }
  });

  /**
   * Gets or sets the currently selected imagery.  This property is observable.
   * @type {ProviderViewModel}
   * @default undefined
   */
  this.selectedImagery = undefined;
  const selectedImageryViewModel = knockout.observable();

  this._currentImageryProviders = [];
  knockout.defineProperty(this, "selectedImagery", {
    get: function () {
      return selectedImageryViewModel();
    },
    set: function (value) {
      if (selectedImageryViewModel() === value) {
        this.dropDownVisible = false;
        return;
      }

      let i;
      const currentImageryProviders = this._currentImageryProviders;
      const currentImageryProvidersLength = currentImageryProviders.length;
      const imageryLayers = this._globe.imageryLayers;
      let hadExistingBaseLayer = false;
      for (i = 0; i < currentImageryProvidersLength; i++) {
        const layersLength = imageryLayers.length;
        for (let x = 0; x < layersLength; x++) {
          const layer = imageryLayers.get(x);
          if (layer.imageryProvider === currentImageryProviders[i]) {
            imageryLayers.remove(layer);
            hadExistingBaseLayer = true;
            break;
          }
        }
      }

      if (defined(value)) {
        const newProviders = value.creationCommand();
        if (Array.isArray(newProviders)) {
          const newProvidersLength = newProviders.length;
          for (i = newProvidersLength - 1; i >= 0; i--) {
            imageryLayers.addImageryProvider(newProviders[i], 0);
          }
          this._currentImageryProviders = newProviders.slice(0);
        } else {
          this._currentImageryProviders = [newProviders];
          if (hadExistingBaseLayer) {
            imageryLayers.addImageryProvider(newProviders, 0);
          } else {
            const baseLayer = imageryLayers.get(0);
            if (defined(baseLayer)) {
              imageryLayers.remove(baseLayer);
            }
            imageryLayers.addImageryProvider(newProviders, 0);
          }
        }
      }
      selectedImageryViewModel(value);
      this.dropDownVisible = false;
    },
  });

  /**
   * Gets or sets the currently selected terrain.  This property is observable.
   * @type {ProviderViewModel}
   * @default undefined
   */
  this.selectedTerrain = undefined;
  const selectedTerrainViewModel = knockout.observable();

  knockout.defineProperty(this, "selectedTerrain", {
    get: function () {
      return selectedTerrainViewModel();
    },
    set: function (value) {
      if (selectedTerrainViewModel() === value) {
        this.dropDownVisible = false;
        return;
      }

      let newProvider;
      if (defined(value)) {
        newProvider = value.creationCommand();
      }

      this._globe.depthTestAgainstTerrain = !(
        newProvider instanceof EllipsoidTerrainProvider
      );
      this._globe.terrainProvider = newProvider;
      selectedTerrainViewModel(value);
      this.dropDownVisible = false;
    },
  });

  const that = this;
  this._toggleDropDown = createCommand(function () {
    that.dropDownVisible = !that.dropDownVisible;
  });

  this.selectedImagery = defaultValue(
    options.selectedImageryProviderViewModel,
    imageryProviderViewModels[0]
  );
  this.selectedTerrain = defaultValue(
    options.selectedTerrainProviderViewModel,
    terrainProviderViewModels[0]
  );
}

Object.defineProperties(BaseLayerPickerViewModel.prototype, {
  /**
   * Gets the command to toggle the visibility of the drop down.
   * @memberof BaseLayerPickerViewModel.prototype
   *
   * @type {Command}
   */
  toggleDropDown: {
    get: function () {
      return this._toggleDropDown;
    },
  },

  /**
   * Gets the globe.
   * @memberof BaseLayerPickerViewModel.prototype
   *
   * @type {Globe}
   */
  globe: {
    get: function () {
      return this._globe;
    },
  },
});
export default BaseLayerPickerViewModel;