From a33be00c08b37409c99f6d7b646c9233ba56e16f Mon Sep 17 00:00:00 2001
From: David Baker <dave@matrix.org>
Date: Tue, 15 Dec 2020 14:59:06 +0000
Subject: [PATCH] Basic call transfer initiation support

Adapt the InviteDialog to select a transfer target

Doesn't support supplying a roo mID fr the transfer: just leaves
the transferee to work out how to contact the target themselves.

MSC2747 (matrix-org/matrix-doc#2747)
Requires https://github.com/matrix-org/matrix-js-sdk/pull/1558
---
 .../views/context_menus/CallContextMenu.tsx   | 18 +++++++++
 src/components/views/dialogs/InviteDialog.tsx | 38 ++++++++++++++++++-
 src/i18n/strings/en_EN.json                   |  1 +
 3 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/src/components/views/context_menus/CallContextMenu.tsx b/src/components/views/context_menus/CallContextMenu.tsx
index 336b72cebfc..35579763260 100644
--- a/src/components/views/context_menus/CallContextMenu.tsx
+++ b/src/components/views/context_menus/CallContextMenu.tsx
@@ -20,6 +20,8 @@ import { _t } from '../../../languageHandler';
 import { ContextMenu, IProps as IContextMenuProps, MenuItem } from '../../structures/ContextMenu';
 import { MatrixCall } from 'matrix-js-sdk/src/webrtc/call';
 import CallHandler from '../../../CallHandler';
+import InviteDialog, { KIND_CALL_TRANSFER } from '../dialogs/InviteDialog';
+import Modal from '../../../Modal';
 
 interface IProps extends IContextMenuProps {
     call: MatrixCall;
@@ -46,14 +48,30 @@ export default class CallContextMenu extends React.Component<IProps> {
         this.props.onFinished();
     }
 
+    onTransferClick = () => {
+        Modal.createTrackedDialog(
+            'Transfer Call', '', InviteDialog, {kind: KIND_CALL_TRANSFER, call: this.props.call},
+            /*className=*/null, /*isPriority=*/false, /*isStatic=*/true,
+        );
+        this.props.onFinished();
+    }
+
     render() {
         const holdUnholdCaption = this.props.call.isRemoteOnHold() ? _t("Resume") : _t("Hold");
         const handler = this.props.call.isRemoteOnHold() ? this.onUnholdClick : this.onHoldClick;
 
+        let transferItem;
+        if (this.props.call.opponentCanBeTransferred()) {
+            transferItem = <MenuItem className="mx_CallContextMenu_item" onClick={this.onTransferClick}>
+                {_t("Transfer")}
+            </MenuItem>;
+        }
+
         return <ContextMenu {...this.props}>
             <MenuItem className="mx_CallContextMenu_item" onClick={handler}>
                 {holdUnholdCaption}
             </MenuItem>
+            {transferItem}
         </ContextMenu>;
     }
 }
diff --git a/src/components/views/dialogs/InviteDialog.tsx b/src/components/views/dialogs/InviteDialog.tsx
index 8ccbbe473cb..5b936e822c6 100644
--- a/src/components/views/dialogs/InviteDialog.tsx
+++ b/src/components/views/dialogs/InviteDialog.tsx
@@ -41,12 +41,14 @@ import SettingsStore from "../../../settings/SettingsStore";
 import {UIFeature} from "../../../settings/UIFeature";
 import CountlyAnalytics from "../../../CountlyAnalytics";
 import {Room} from "matrix-js-sdk/src/models/room";
+import { MatrixCall } from 'matrix-js-sdk/src/webrtc/call';
 
 // we have a number of types defined from the Matrix spec which can't reasonably be altered here.
 /* eslint-disable camelcase */
 
 export const KIND_DM = "dm";
 export const KIND_INVITE = "invite";
+export const KIND_CALL_TRANSFER = "call_transfer";
 
 const INITIAL_ROOMS_SHOWN = 3; // Number of rooms to show at first
 const INCREMENT_ROOMS_SHOWN = 5; // Number of rooms to add when 'show more' is clicked
@@ -310,6 +312,9 @@ interface IInviteDialogProps {
     // The room ID this dialog is for. Only required for KIND_INVITE.
     roomId: string,
 
+    // The call to transfer. Only required for KIND_CALL_TRANSFER.
+    call: MatrixCall,
+
     // Initial value to populate the filter with
     initialText: string,
 }
@@ -345,6 +350,8 @@ export default class InviteDialog extends React.PureComponent<IInviteDialogProps
 
         if (props.kind === KIND_INVITE && !props.roomId) {
             throw new Error("When using KIND_INVITE a roomId is required for an InviteDialog");
+        } else if (props.kind === KIND_CALL_TRANSFER && !props.call) {
+            throw new Error("When using KIND_CALL_TRANSFER a call is required for an InviteDialog");
         }
 
         const alreadyInvited = new Set([MatrixClientPeg.get().getUserId(), SdkConfig.get()['welcomeUserId']]);
@@ -702,6 +709,29 @@ export default class InviteDialog extends React.PureComponent<IInviteDialogProps
         });
     };
 
+    _transferCall = async () => {
+        this._convertFilter();
+        const targets = this._convertFilter();
+        const targetIds = targets.map(t => t.userId);
+        if (targetIds.length > 1) {
+            this.setState({
+                errorText: _t("A call can only be transferred to a single user."),
+            });
+        }
+
+        this.setState({busy: true});
+        try {
+            await this.props.call.transfer(targetIds[0]);
+            this.setState({busy: false});
+            this.props.onFinished();
+        } catch (e) {
+            this.setState({
+                busy: false,
+                errorText: _t("Failed to transfer call"),
+            });
+        }
+    };
+
     _onKeyDown = (e) => {
         if (this.state.busy) return;
         const value = e.target.value.trim();
@@ -1217,7 +1247,7 @@ export default class InviteDialog extends React.PureComponent<IInviteDialogProps
             }
             buttonText = _t("Go");
             goButtonFn = this._startDm;
-        } else { // KIND_INVITE
+        } else if (this.props.kind === KIND_INVITE) {
             title = _t("Invite to this room");
 
             if (identityServersEnabled) {
@@ -1251,6 +1281,12 @@ export default class InviteDialog extends React.PureComponent<IInviteDialogProps
 
             buttonText = _t("Invite");
             goButtonFn = this._inviteUsers;
+        } else if (this.props.kind === KIND_CALL_TRANSFER) {
+            title = _t("Transfer");
+            buttonText = _t("Transfer");
+            goButtonFn = this._transferCall;
+        } else {
+            console.error("Unknown kind of InviteDialog: " + this.props.kind);
         }
 
         const hasSelection = this.state.targets.length > 0
diff --git a/src/i18n/strings/en_EN.json b/src/i18n/strings/en_EN.json
index eb1d0a632e7..5e4452a4bc2 100644
--- a/src/i18n/strings/en_EN.json
+++ b/src/i18n/strings/en_EN.json
@@ -2267,6 +2267,7 @@
     "If you've forgotten your recovery key you can <button>set up new recovery options</button>": "If you've forgotten your recovery key you can <button>set up new recovery options</button>",
     "Resume": "Resume",
     "Hold": "Hold",
+    "Transfer": "Transfer",
     "Reject invitation": "Reject invitation",
     "Are you sure you want to reject the invitation?": "Are you sure you want to reject the invitation?",
     "Unable to reject invite": "Unable to reject invite",