/// <reference path="oskSubKey.ts" />
/// <reference path="../realizedGesture.interface.ts" />

namespace com.keyman.osk.browser {
  /**
   * Represents a 'realized' longpress gesture's default implementation
   * within KeymanWeb.  Once a touch sequence has been confirmed to
   * correspond to a longpress gesture, implementations of this class
   * provide the following:
   * * The UI needed to present a subkey menu
   * * The state management needed to present feedback about the
   * currently-selected subkey to the user
   * * A `Promise` that will resolve to the user's selected subkey
   * once the longpress operation is complete.
   *
   * As selection of the subkey occurs after the subkey popup is
   * displayed, selection of the subkey is inherently asynchronous.
   * The `Promise` may also resolve to `null` if the user indicates
   * the desire to cancel subkey selection.
   */
  export class SubkeyPopup implements RealizedGesture {
    public readonly element: HTMLDivElement;
    public readonly shim: HTMLDivElement;

    private vkbd: VisualKeyboard;
    private currentSelection: KeyElement;

    private callout: HTMLDivElement;

    public readonly baseKey: KeyElement;
    public readonly promise: Promise<text.KeyEvent>;

    // Resolves the promise that generated this SubkeyPopup.
    private resolver: (keyEvent: text.KeyEvent) => void;

    constructor(vkbd: VisualKeyboard, e: KeyElement) {
      let keyman = com.keyman.singleton;
      let _this = this;

      this.promise = new Promise<text.KeyEvent>(function(resolve) {
        _this.resolver = resolve;
      })

      this.vkbd = vkbd;
      this.baseKey = e;

      // If the user doesn't move their finger and releases, we'll output the base key
      // by default.
      this.currentSelection = e;
      e.key.highlight(true);

      // A tag we directly set on a key element during its construction.
      let subKeySpec: OSKKeySpec[] = e['subKeys'];

      // The holder is position:fixed, but the keys do not need to be, as no scrolling
      // is possible while the array is visible.  So it is simplest to let the keys have
      // position:static and display:inline-block
      var subKeys = this.element = document.createElement('div');

      var i;
      subKeys.id='kmw-popup-keys';

      // #3718: No longer prepend base key to popup array

      // Must set position dynamically, not in CSS
      var ss=subKeys.style;

      // Set key font according to layout, or defaulting to OSK font
      // (copied, not inherited, since OSK is not a parent of popup keys)
      ss.fontFamily=vkbd.fontFamily;

      // Copy the font size from the parent key, allowing for style inheritance
      ss.fontSize=keyman.util.getStyleValue(e,'font-size');
      ss.visibility='hidden';

      var nKeys=subKeySpec.length,nRows,nCols;
      nRows=Math.min(Math.ceil(nKeys/9),2);
      nCols=Math.ceil(nKeys/nRows);
      ss.width=(nCols*e.offsetWidth+nCols*5)+'px';

      // Add nested button elements for each sub-key
      for(i=0; i<nKeys; i++) {
        var needsTopMargin = false;
        let nRow=Math.floor(i/nCols);
        if(nRows > 1 && nRow > 0) {
          needsTopMargin = true;
        }

        let layer = e['key'].layer;
        if(typeof(layer) != 'string' || layer == '') {
          // Use the currently-active layer.
          layer = vkbd.layerId;
        }
        let keyGenerator = new OSKSubKey(subKeySpec[i], layer);
        let kDiv = keyGenerator.construct(vkbd, <KeyElement> e, needsTopMargin);

        subKeys.appendChild(kDiv);
      }

      // And add a filter to fade main keyboard
      this.shim = document.createElement('div');
      this.shim.id = 'kmw-popup-shim';

      // Highlight the duplicated base key or ideal subkey (if a phone)
      if(vkbd.device.formFactor == utils.FormFactor.Phone) {
        this.selectDefaultSubkey(vkbd, e, subKeys /* == this.element */);
      }
    }

    finalize(input: InputEventCoordinate) {
      if(this.resolver) {
        let keyEvent: text.KeyEvent = null;
        if(this.currentSelection) {
          keyEvent = this.vkbd.initKeyEvent(this.currentSelection, input);
          this.currentSelection.key.highlight(false);
        }
        this.resolver(keyEvent);
      }
      this.resolver = null;
    }

    reposition(vkbd: VisualKeyboard) {
      let keyman = com.keyman.singleton;

      let subKeys = this.element;
      let e = this.baseKey;

      // And correct its position with respect to that element
      const _Box = vkbd.element.offsetParent as HTMLDivElement;
      let rowElement = (e.key as OSKBaseKey).row.element;
      let ss=subKeys.style;
      var x = e.offsetLeft + (<HTMLElement>e.offsetParent).offsetLeft + 0.5*(e.offsetWidth-subKeys.offsetWidth);
      var xMax = keyman.osk.computedWidth - subKeys.offsetWidth;

      if(x > xMax) {
        x=xMax;
      }
      if(x < 0) {
        x=0;
      }
      ss.left=x+'px';

      let _BoxRect = _Box.getBoundingClientRect();
      let rowElementRect = rowElement.getBoundingClientRect();
      ss.top = (rowElementRect.top - _BoxRect.top - subKeys.offsetHeight - 3) + 'px';

      // Make the popup keys visible
      ss.visibility='visible';

      // For now, should only be true (in production) when keyman.isEmbedded == true.
      let constrainPopup = keyman.isEmbedded;

      let cs = getComputedStyle(subKeys);
      let topY = parseFloat(cs.top);

      // Adjust the vertical position of the popup to keep it within the
      // bounds of the keyboard rectangle, when on iPhone (system keyboard)
      const topOffset = 0; // Set this when testing constrainPopup, e.g. to -80px
      let delta = 0;
      if(topY < topOffset && constrainPopup) {
        delta = topOffset - topY;
        ss.top = topOffset + 'px';
      }

      // Add the callout
      if(vkbd.device.formFactor == utils.FormFactor.Phone && vkbd.device.OS == utils.OperatingSystem.iOS) {
        this.callout = this.addCallout(e, delta);
      }
    }

    /**
     * Add a callout for popup keys (if KeymanWeb on a phone device)
     *
     * @param   {Object}  key   HTML key element
     * @return  {Object}        callout object
     */
    addCallout(key: KeyElement, delta?: number): HTMLDivElement {
      let keyman = com.keyman.singleton;

      delta = delta || 0;

      let calloutHeight = key.offsetHeight - delta + 6;

      if(calloutHeight > 0) {
        var cc = document.createElement('div'), ccs = cc.style;
        cc.id = 'kmw-popup-callout';
        keyman.osk._Box.appendChild(cc);

        // Create the callout
        let keyRect = key.getBoundingClientRect();
        let _BoxRect = keyman.osk._Box.getBoundingClientRect();

        // Set position and style
        // We're going to adjust the top of the box to ensure it stays
        // pixel aligned, otherwise we can get antialiasing artifacts
        // that look ugly
        let top = Math.floor(keyRect.top - _BoxRect.top - 9 + delta);
        ccs.top = top + 'px';
        ccs.left = (keyRect.left - _BoxRect.left) + 'px';
        ccs.width = keyRect.width + 'px';
        ccs.height = (keyRect.bottom - _BoxRect.top - top - 1) + 'px'; //(height - 1) + 'px';

        // Return callout element, to allow removal later
        return cc;
      } else {
        return null;
      }
    }

    selectDefaultSubkey(vkbd: VisualKeyboard, baseKey: KeyElement, popupBase: HTMLElement) {
      var bk: KeyElement;
      let subkeys = baseKey['subKeys'];
      for(let i=0; i < subkeys.length; i++) {
        let skSpec = subkeys[i];
        let skElement = <KeyElement> popupBase.childNodes[i].firstChild;

        // Preference order:
        // #1:  if a default subkey has been specified, select it.  (pending, for 15.0+)
        // #2:  if no default subkey is specified, default to a subkey with the same
        //      key ID and layer / modifier spec.
        //if(skSpec.isDefault) { TODO for 15.0
        //  bk = skElement;
        //  break;
        //} else
        if(!baseKey.key || !baseKey.key.spec) {
          continue;
        }

        if(skSpec.elementID == baseKey.key.spec.elementID) {
          bk = skElement;
          break; // Best possible match has been found.  (Disable 'break' once above block is implemented.)
        }
      }

      if(bk) {
        vkbd.keyPending = bk;
        // Subkeys never get key previews, so we can directly highlight the subkey.
        bk.key.highlight(true);
      }
    }

    isVisible(): boolean {
      return this.element.style.visibility == 'visible';
    }

    clear() {
      // Discard the reference to the Promise's resolve method, allowing
      // GC to clean it up.  The corresponding Promise's contract allows
      // passive cancellation.
      this.resolver = null;

      // Remove the displayed subkey array, if any
      if(this.element.parentNode) {
        this.element.parentNode.removeChild(this.element);
      }

      if(this.shim.parentNode) {
        this.shim.parentNode.removeChild(this.shim);
      }

      if(this.callout && this.callout.parentNode) {
        this.callout.parentNode.removeChild(this.callout);
      }
    }

    updateTouch(input: InputEventCoordinate) {
      this.currentSelection = null;
      this.baseKey.key.highlight(false);

      for(let i=0; i < this.baseKey['subKeys'].length; i++) {
        try {
          let sk = this.element.childNodes[i].firstChild as KeyElement;

          let onKey = sk.key.isUnderTouch(input);
          if(onKey) {
            this.currentSelection = sk;
          }
          sk.key.highlight(onKey);
        } catch(ex) {
          if(ex.message) {
            console.error("Unexpected error when attempting to update selected subkey:" + ex.message);
          } else {
            console.error("Unexpected error (and error type) when attempting to update selected subkey.");
          }
        }
      }

      // Use the popup duplicate of the base key if a phone with a visible popup array
      if(!this.currentSelection && this.baseKey.key.isUnderTouch(input)) {
        this.baseKey.key.highlight(true);
        this.currentSelection = this.baseKey;
      }
    }
  }
}