/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

const { GeckoViewActorChild } = ChromeUtils.import(
  "resource://gre/modules/GeckoViewActorChild.jsm"
);
const { XPCOMUtils } = ChromeUtils.import(
  "resource://gre/modules/XPCOMUtils.jsm"
);
const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
const EXPORTED_SYMBOLS = ["SelectionActionDelegateChild"];

// Dispatches GeckoView:ShowSelectionAction and GeckoView:HideSelectionAction to
// the GeckoSession on accessible caret changes.
class SelectionActionDelegateChild extends GeckoViewActorChild {
  constructor(aModuleName, aMessageManager) {
    super(aModuleName, aMessageManager);

    this._seqNo = 0;
    this._isActive = false;
    this._previousMessage = "";
  }

  _actions = [
    {
      id: "org.mozilla.geckoview.HIDE",
      predicate: _ => true,
      perform: _ => this.handleEvent({ type: "pagehide" }),
    },
    {
      id: "org.mozilla.geckoview.CUT",
      predicate: e =>
        !e.collapsed && e.selectionEditable && !this._isPasswordField(e),
      perform: _ => this.docShell.doCommand("cmd_cut"),
    },
    {
      id: "org.mozilla.geckoview.COPY",
      predicate: e => !e.collapsed && !this._isPasswordField(e),
      perform: _ => this.docShell.doCommand("cmd_copy"),
    },
    {
      id: "org.mozilla.geckoview.PASTE",
      predicate: e =>
        e.selectionEditable &&
        Services.clipboard.hasDataMatchingFlavors(
          ["text/unicode"],
          Ci.nsIClipboard.kGlobalClipboard
        ),
      perform: _ => this._performPaste(),
    },
    {
      id: "org.mozilla.geckoview.DELETE",
      predicate: e => !e.collapsed && e.selectionEditable,
      perform: _ => this.docShell.doCommand("cmd_delete"),
    },
    {
      id: "org.mozilla.geckoview.COLLAPSE_TO_START",
      predicate: e => !e.collapsed && e.selectionEditable,
      perform: e => this.docShell.doCommand("cmd_moveLeft"),
    },
    {
      id: "org.mozilla.geckoview.COLLAPSE_TO_END",
      predicate: e => !e.collapsed && e.selectionEditable,
      perform: e => this.docShell.doCommand("cmd_moveRight"),
    },
    {
      id: "org.mozilla.geckoview.UNSELECT",
      predicate: e => !e.collapsed && !e.selectionEditable,
      perform: e => this.docShell.doCommand("cmd_selectNone"),
    },
    {
      id: "org.mozilla.geckoview.SELECT_ALL",
      predicate: e => {
        if (e.reason === "longpressonemptycontent") {
          return false;
        }
        if (e.selectionEditable && e.target && e.target.activeElement) {
          const element = e.target.activeElement;
          let value = "";
          if (element.value) {
            value = element.value;
          } else if (
            element.isContentEditable ||
            e.target.designMode === "on"
          ) {
            value = element.innerText;
          }
          // Do not show SELECT_ALL if the editable is empty
          // or all the editable text is already selected.
          return value !== "" && value !== e.selectedTextContent;
        }
        return true;
      },
      perform: e => this.docShell.doCommand("cmd_selectAll"),
    },
  ];

  _performPaste() {
    this.handleEvent({ type: "pagehide" });
    this.docShell.doCommand("cmd_paste");
  }

  _isPasswordField(aEvent) {
    if (!aEvent.selectionEditable) {
      return false;
    }

    const win = aEvent.target.defaultView;
    const focus = aEvent.target.activeElement;
    return (
      win &&
      win.HTMLInputElement &&
      focus instanceof win.HTMLInputElement &&
      !focus.mozIsTextField(/* excludePassword */ true)
    );
  }

  _getFrameOffset(aEvent) {
    // Get correct offset in case of nested iframe.
    const offset = {
      left: 0,
      top: 0,
    };

    let currentWindow = aEvent.target.defaultView;
    while (currentWindow.realFrameElement) {
      const frameElement = currentWindow.realFrameElement;
      currentWindow = frameElement.ownerGlobal;

      // The offset of the iframe window relative to the parent window
      // includes the iframe's border, and the iframe's origin in its
      // containing document.
      const currentRect = frameElement.getBoundingClientRect();
      const style = currentWindow.getComputedStyle(frameElement);
      const borderLeft = parseFloat(style.borderLeftWidth) || 0;
      const borderTop = parseFloat(style.borderTopWidth) || 0;
      const paddingLeft = parseFloat(style.paddingLeft) || 0;
      const paddingTop = parseFloat(style.paddingTop) || 0;

      offset.left += currentRect.left + borderLeft + paddingLeft;
      offset.top += currentRect.top + borderTop + paddingTop;

      const targetDocShell = currentWindow.docShell;
      if (targetDocShell.isMozBrowser) {
        break;
      }
    }

    // Now we have coordinates relative to the root content document's
    // layout viewport. Subtract the offset of the visual viewport
    // relative to the layout viewport, to get coordinates relative to
    // the visual viewport.
    var offsetX = {};
    var offsetY = {};
    currentWindow.windowUtils.getVisualViewportOffsetRelativeToLayoutViewport(
      offsetX,
      offsetY
    );
    offset.left -= offsetX.value;
    offset.top -= offsetY.value;

    return offset;
  }

  /**
   * Receive and act on AccessibleCarets caret state-change
   * (mozcaretstatechanged and pagehide) events.
   */
  handleEvent(aEvent) {
    if (aEvent.type === "pagehide" || aEvent.type === "deactivate") {
      // Hide any selection actions on page hide or deactivate.
      aEvent = {
        reason: "visibilitychange",
        caretVisibile: false,
        selectionVisible: false,
        collapsed: true,
        selectionEditable: false,
      };
    }

    let reason = aEvent.reason;

    if (this._isActive && !aEvent.caretVisible) {
      // For mozcaretstatechanged, "visibilitychange" means the caret is hidden.
      reason = "visibilitychange";
    } else if (!aEvent.collapsed && !aEvent.selectionVisible) {
      reason = "invisibleselection";
    } else if (
      !this._isActive &&
      aEvent.selectionEditable &&
      aEvent.collapsed &&
      reason !== "longpressonemptycontent" &&
      reason !== "taponcaret" &&
      !Services.prefs.getBoolPref(
        "geckoview.selection_action.show_on_focus",
        false
      )
    ) {
      // Don't show selection actions when merely focusing on an editor or
      // repositioning the cursor. Wait until long press or the caret is tapped
      // in order to match Android behavior.
      reason = "visibilitychange";
    }

    debug`handleEvent: ${reason}`;

    if (
      [
        "longpressonemptycontent",
        "releasecaret",
        "taponcaret",
        "updateposition",
      ].includes(reason)
    ) {
      const actions = this._actions.filter(action =>
        action.predicate.call(this, aEvent)
      );

      const offset = this._getFrameOffset(aEvent);
      const password = this._isPasswordField(aEvent);

      const msg = {
        type: "GeckoView:ShowSelectionAction",
        seqNo: this._seqNo,
        collapsed: aEvent.collapsed,
        editable: aEvent.selectionEditable,
        password,
        selection: password ? "" : aEvent.selectedTextContent,
        clientRect: !aEvent.boundingClientRect
          ? null
          : {
              left: aEvent.boundingClientRect.left + offset.left,
              top: aEvent.boundingClientRect.top + offset.top,
              right: aEvent.boundingClientRect.right + offset.left,
              bottom: aEvent.boundingClientRect.bottom + offset.top,
            },
        actions: actions.map(action => action.id),
      };

      try {
        if (msg.clientRect) {
          msg.clientRect.bottom += parseFloat(
            Services.prefs.getCharPref("layout.accessiblecaret.height", "0")
          );
        }
      } catch (e) {}

      if (this._isActive && JSON.stringify(msg) === this._previousMessage) {
        // Don't call again if we're already active and things haven't changed.
        return;
      }

      msg.seqNo = ++this._seqNo;
      this._isActive = true;
      this._previousMessage = JSON.stringify(msg);

      this.eventDispatcher.sendRequest(msg, {
        onSuccess: response => {
          if (response.seqNo !== this._seqNo) {
            // Stale action.
            warn`Stale response ${response.id}`;
            return;
          }
          const action = actions.find(action => action.id === response.id);
          if (action) {
            debug`Performing ${response.id}`;
            action.perform.call(this, aEvent, response);
          } else {
            warn`Invalid action ${response.id}`;
          }
        },
        onError: _ => {
          // Do nothing; we can get here if the delegate was just unregistered.
        },
      });
    } else if (
      [
        "invisibleselection",
        "presscaret",
        "scroll",
        "visibilitychange",
      ].includes(reason)
    ) {
      if (!this._isActive) {
        return;
      }

      this._isActive = false;

      // Mark previous actions as stale. Don't do this for "invisibleselection"
      // or "scroll" because previous actions should still be valid even after
      // these events occur.
      if (reason !== "invisibleselection" && reason !== "scroll") {
        this._seqNo++;
      }

      this.eventDispatcher.sendRequest({
        type: "GeckoView:HideSelectionAction",
        reason,
      });
    } else {
      warn`Unknown reason: ${reason}`;
    }
  }
}

const { debug, warn } = SelectionActionDelegateChild.initLogging(
  "SelectionActionDelegate"
);