/*
Copyright 2015, 2016 OpenMarket Ltd

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

/*
 * Manages a list of all the currently active calls.
 *
 * This handler dispatches when voip calls are added/updated/removed from this list:
 * {
 *   action: 'call_state'
 *   room_id: <room ID of the call>
 * }
 *
 * To know the state of the call, this handler exposes a getter to
 * obtain the call for a room:
 *   var call = CallHandler.getCall(roomId)
 *   var state = call.call_state; // ringing|ringback|connected|ended|busy|stop_ringback|stop_ringing
 *
 * This handler listens for and handles the following actions:
 * {
 *   action: 'place_call',
 *   type: 'voice|video',
 *   room_id: <room that the place call button was pressed in>
 * }
 *
 * {
 *   action: 'incoming_call'
 *   call: MatrixCall
 * }
 *
 * {
 *   action: 'hangup'
 *   room_id: <room that the hangup button was pressed in>
 * }
 *
 * {
 *   action: 'answer'
 *   room_id: <room that the answer button was pressed in>
 * }
 */

var MatrixClientPeg = require('./MatrixClientPeg');
var PlatformPeg = require("./PlatformPeg");
var Modal = require('./Modal');
var sdk = require('./index');
var Matrix = require("matrix-js-sdk");
var dis = require("./dispatcher");

global.mxCalls = {
    //room_id: MatrixCall
};
var calls = global.mxCalls;
var ConferenceHandler = null;

var audioPromises = {};

function play(audioId) {
    // TODO: Attach an invisible element for this instead
    // which listens?
    var audio = document.getElementById(audioId);
    if (audio) {
        if (audioPromises[audioId]) {
            audioPromises[audioId] = audioPromises[audioId].then(()=>{
                audio.load();
                return audio.play();
            });
        }
        else {
            audioPromises[audioId] = audio.play();
        }
    }
}

function pause(audioId) {
    // TODO: Attach an invisible element for this instead
    // which listens?
    var audio = document.getElementById(audioId);
    if (audio) {
        if (audioPromises[audioId]) {
            audioPromises[audioId] = audioPromises[audioId].then(()=>audio.pause());
        }
        else {
            // pause doesn't actually return a promise, but might as well do this for symmetry with play();
            audioPromises[audioId] = audio.pause();
        }
    }
}

function _setCallListeners(call) {
    call.on("error", function(err) {
        console.error("Call error: %s", err);
        console.error(err.stack);
        call.hangup();
        _setCallState(undefined, call.roomId, "ended");
    });
    call.on("hangup", function() {
        _setCallState(undefined, call.roomId, "ended");
    });
    // map web rtc states to dummy UI state
    // ringing|ringback|connected|ended|busy|stop_ringback|stop_ringing
    call.on("state", function(newState, oldState) {
        if (newState === "ringing") {
            _setCallState(call, call.roomId, "ringing");
            pause("ringbackAudio");
        }
        else if (newState === "invite_sent") {
            _setCallState(call, call.roomId, "ringback");
            play("ringbackAudio");
        }
        else if (newState === "ended" && oldState === "connected") {
            _setCallState(undefined, call.roomId, "ended");
            pause("ringbackAudio");
            play("callendAudio");
        }
        else if (newState === "ended" && oldState === "invite_sent" &&
                (call.hangupParty === "remote" ||
                (call.hangupParty === "local" && call.hangupReason === "invite_timeout")
                )) {
            _setCallState(call, call.roomId, "busy");
            pause("ringbackAudio");
            play("busyAudio");
            var ErrorDialog = sdk.getComponent("dialogs.ErrorDialog");
            Modal.createDialog(ErrorDialog, {
                title: "Call Timeout",
                description: "The remote side failed to pick up."
            });
        }
        else if (oldState === "invite_sent") {
            _setCallState(call, call.roomId, "stop_ringback");
            pause("ringbackAudio");
        }
        else if (oldState === "ringing") {
            _setCallState(call, call.roomId, "stop_ringing");
            pause("ringbackAudio");
        }
        else if (newState === "connected") {
            _setCallState(call, call.roomId, "connected");
            pause("ringbackAudio");
        }
    });
}

function _setCallState(call, roomId, status) {
    console.log(
        "Call state in %s changed to %s (%s)", roomId, status, (call ? call.call_state : "-")
    );
    calls[roomId] = call;

    if (status === "ringing") {
        play("ringAudio")
    }
    else if (call && call.call_state === "ringing") {
        pause("ringAudio")
    }

    if (call) {
        call.call_state = status;
    }
    dis.dispatch({
        action: 'call_state',
        room_id: roomId
    });
}

function _onAction(payload) {
    function placeCall(newCall) {
        _setCallListeners(newCall);
        _setCallState(newCall, newCall.roomId, "ringback");
        if (payload.type === 'voice') {
            newCall.placeVoiceCall();
        }
        else if (payload.type === 'video') {
            newCall.placeVideoCall(
                payload.remote_element,
                payload.local_element
            );
        }
        else if (payload.type === 'screensharing') {
            const screenCapErrorString = PlatformPeg.get().screenCaptureErrorString();
            if (screenCapErrorString) {
                _setCallState(undefined, newCall.roomId, "ended");
                console.log("Can't capture screen: " + screenCapErrorString);
                const ErrorDialog = sdk.getComponent("dialogs.ErrorDialog");
                Modal.createDialog(ErrorDialog, {
                    title: "Unable to capture screen",
                    description: screenCapErrorString
                });
                return;
            }
            newCall.placeScreenSharingCall(
                payload.remote_element,
                payload.local_element
            );
        }
        else {
            console.error("Unknown conf call type: %s", payload.type);
        }
    }

    switch (payload.action) {
        case 'place_call':
            if (module.exports.getAnyActiveCall()) {
                const ErrorDialog = sdk.getComponent("dialogs.ErrorDialog");
                Modal.createDialog(ErrorDialog, {
                    title: "Existing Call",
                    description: "You are already in a call."
                });
                return; // don't allow >1 call to be placed.
            }

            // if the runtime env doesn't do VoIP, whine.
            if (!MatrixClientPeg.get().supportsVoip()) {
                const ErrorDialog = sdk.getComponent("dialogs.ErrorDialog");
                Modal.createDialog(ErrorDialog, {
                    title: "VoIP is unsupported",
                    description: "You cannot place VoIP calls in this browser."
                });
                return;
            }

            var room = MatrixClientPeg.get().getRoom(payload.room_id);
            if (!room) {
                console.error("Room %s does not exist.", payload.room_id);
                return;
            }

            var members = room.getJoinedMembers();
            if (members.length <= 1) {
                const ErrorDialog = sdk.getComponent("dialogs.ErrorDialog");
                Modal.createDialog(ErrorDialog, {
                    description: "You cannot place a call with yourself."
                });
                return;
            }
            else if (members.length === 2) {
                console.log("Place %s call in %s", payload.type, payload.room_id);
                var call = Matrix.createNewMatrixCall(
                    MatrixClientPeg.get(), payload.room_id
                );
                placeCall(call);
            }
            else { // > 2
                dis.dispatch({
                    action: "place_conference_call",
                    room_id: payload.room_id,
                    type: payload.type,
                    remote_element: payload.remote_element,
                    local_element: payload.local_element
                });
            }
            break;
        case 'place_conference_call':
            console.log("Place conference call in %s", payload.room_id);
            if (!ConferenceHandler) {
                const ErrorDialog = sdk.getComponent("dialogs.ErrorDialog");
                Modal.createDialog(ErrorDialog, {
                    description: "Conference calls are not supported in this client"
                });
            }
            else if (!MatrixClientPeg.get().supportsVoip()) {
                const ErrorDialog = sdk.getComponent("dialogs.ErrorDialog");
                Modal.createDialog(ErrorDialog, {
                    title: "VoIP is unsupported",
                    description: "You cannot place VoIP calls in this browser."
                });
            }
            else if (MatrixClientPeg.get().isRoomEncrypted(payload.room_id)) {
                // Conference calls are implemented by sending the media to central
                // server which combines the audio from all the participants together
                // into a single stream. This is incompatible with end-to-end encryption
                // because a central server would be decrypting the audio for each
                // participant.
                // Therefore we disable conference calling in E2E rooms.
                const ErrorDialog = sdk.getComponent("dialogs.ErrorDialog");
                Modal.createDialog(ErrorDialog, {
                    description: "Conference calls are not supported in encrypted rooms",
                });
            }
            else {
                var QuestionDialog = sdk.getComponent("dialogs.QuestionDialog");
                Modal.createDialog(QuestionDialog, {
                    title: "Warning!",
                    description: "Conference calling is in development and may not be reliable.",
                    onFinished: confirm=>{
                        if (confirm) {
                            ConferenceHandler.createNewMatrixCall(
                                MatrixClientPeg.get(), payload.room_id
                            ).done(function(call) {
                                placeCall(call);
                            }, function(err) {
                                const ErrorDialog = sdk.getComponent("dialogs.ErrorDialog");
                                Modal.createDialog(ErrorDialog, {
                                    title: "Failed to set up conference call",
                                    description: "Conference call failed: " + err,
                                });
                            });
                        }
                    },
                });
            }
            break;
        case 'incoming_call':
            if (module.exports.getAnyActiveCall()) {
                // ignore multiple incoming calls. in future, we may want a line-1/line-2 setup.
                // we avoid rejecting with "busy" in case the user wants to answer it on a different device.
                // in future we could signal a "local busy" as a warning to the caller.
                // see https://github.com/vector-im/vector-web/issues/1964
                return;
            }

            // if the runtime env doesn't do VoIP, stop here.
            if (!MatrixClientPeg.get().supportsVoip()) {
                return;
            }

            var call = payload.call;
            _setCallListeners(call);
            _setCallState(call, call.roomId, "ringing");
            break;
        case 'hangup':
            if (!calls[payload.room_id]) {
                return; // no call to hangup
            }
            calls[payload.room_id].hangup();
            _setCallState(null, payload.room_id, "ended");
            break;
        case 'answer':
            if (!calls[payload.room_id]) {
                return; // no call to answer
            }
            calls[payload.room_id].answer();
            _setCallState(calls[payload.room_id], payload.room_id, "connected");
            dis.dispatch({
                action: "view_room",
                room_id: payload.room_id
            });
            break;
    }
}
// FIXME: Nasty way of making sure we only register
// with the dispatcher once
if (!global.mxCallHandler) {
    dis.register(_onAction);
}

var callHandler = {
    getCallForRoom: function(roomId) {
        var call = module.exports.getCall(roomId);
        if (call) return call;

        if (ConferenceHandler) {
            call = ConferenceHandler.getConferenceCallForRoom(roomId);
        }
        if (call) return call;

        return null;
    },

    getCall: function(roomId) {
        return calls[roomId] || null;
    },

    getAnyActiveCall: function() {
        var roomsWithCalls = Object.keys(calls);
        for (var i = 0; i < roomsWithCalls.length; i++) {
            if (calls[roomsWithCalls[i]] &&
                    calls[roomsWithCalls[i]].call_state !== "ended") {
                return calls[roomsWithCalls[i]];
            }
        }
        return null;
    },

    setConferenceHandler: function(confHandler) {
        ConferenceHandler = confHandler;
    },

    getConferenceHandler: function() {
        return ConferenceHandler;
    }
};
// Only things in here which actually need to be global are the
// calls list (done separately) and making sure we only register
// with the dispatcher once (which uses this mechanism but checks
// separately). This could be tidied up.
if (global.mxCallHandler === undefined) {
    global.mxCallHandler = callHandler;
}

module.exports = global.mxCallHandler;