/*
Copyright 2022 Matrix.org Foundation C.I.C.

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.
*/

import React, {
  useEffect,
  useCallback,
  useMemo,
  useRef,
  useState,
} from "react";
import { usePreventScroll } from "@react-aria/overlays";
import useMeasure from "react-use-measure";
import { ResizeObserver } from "@juggle/resize-observer";
import { MatrixClient } from "matrix-js-sdk/src/client";
import { RoomMember } from "matrix-js-sdk/src/models/room-member";
import { GroupCall } from "matrix-js-sdk/src/webrtc/groupCall";
import { CallFeed } from "matrix-js-sdk/src/webrtc/callFeed";
import classNames from "classnames";
import { useTranslation } from "react-i18next";
import { JoinRule } from "matrix-js-sdk/src/@types/partials";
import {
  CallEvent,
  CallState,
  MatrixCall,
} from "matrix-js-sdk/src/webrtc/call";

import type { IWidgetApiRequest } from "matrix-widget-api";
import styles from "./InCallView.module.css";
import {
  HangupButton,
  MicButton,
  VideoButton,
  ScreenshareButton,
} from "../button";
import {
  Header,
  LeftNav,
  RightNav,
  RoomHeaderInfo,
  VersionMismatchWarning,
} from "../Header";
import { VideoGrid, useVideoGridLayout } from "../video-grid/VideoGrid";
import { VideoTileContainer } from "../video-grid/VideoTileContainer";
import { GroupCallInspector } from "./GroupCallInspector";
import { OverflowMenu } from "./OverflowMenu";
import { GridLayoutMenu } from "./GridLayoutMenu";
import { Avatar } from "../Avatar";
import { UserMenuContainer } from "../UserMenuContainer";
import { useRageshakeRequestModal } from "../settings/submit-rageshake";
import { RageshakeRequestModal } from "./RageshakeRequestModal";
import { useMediaHandler } from "../settings/useMediaHandler";
import { useShowInspector, useSpatialAudio } from "../settings/useSetting";
import { useModalTriggerState } from "../Modal";
import { useAudioContext } from "../video-grid/useMediaStream";
import { useFullscreen } from "../video-grid/useFullscreen";
import { AudioContainer } from "../video-grid/AudioContainer";
import { useAudioOutputDevice } from "../video-grid/useAudioOutputDevice";
import { PosthogAnalytics } from "../PosthogAnalytics";
import { widget, ElementWidgetActions } from "../widget";
import { useJoinRule } from "./useJoinRule";
import { useUrlParams } from "../UrlParams";
import { usePrefersReducedMotion } from "../usePrefersReducedMotion";

const canScreenshare = "getDisplayMedia" in (navigator.mediaDevices ?? {});
// There is currently a bug in Safari our our code with cloning and sending MediaStreams
// or with getUsermedia and getDisplaymedia being used within the same session.
// For now we can disable screensharing in Safari.
const isSafari = /^((?!chrome|android).)*safari/i.test(navigator.userAgent);

interface Props {
  client: MatrixClient;
  groupCall: GroupCall;
  participants: RoomMember[];
  calls: MatrixCall[];
  roomName: string;
  avatarUrl: string;
  microphoneMuted: boolean;
  localVideoMuted: boolean;
  toggleLocalVideoMuted: () => void;
  toggleMicrophoneMuted: () => void;
  toggleScreensharing: () => void;
  userMediaFeeds: CallFeed[];
  activeSpeaker: string;
  onLeave: () => void;
  isScreensharing: boolean;
  screenshareFeeds: CallFeed[];
  roomIdOrAlias: string;
  unencryptedEventsFromUsers: Set<string>;
  hideHeader: boolean;
}

export enum ConnectionState {
  ESTABLISHING_CALL = "establishing call", // call hasn't been established yet
  WAIT_MEDIA = "wait_media", // call is set up, waiting for ICE to connect
  CONNECTED = "connected", // media is flowing
}

// Represents something that should get a tile on the layout,
// ie. a user's video feed or a screen share feed.
export interface TileDescriptor {
  id: string;
  member: RoomMember;
  focused: boolean;
  presenter: boolean;
  callFeed?: CallFeed;
  isLocal?: boolean;
  connectionState: ConnectionState;
}

export function InCallView({
  client,
  groupCall,
  participants,
  calls,
  roomName,
  avatarUrl,
  microphoneMuted,
  localVideoMuted,
  toggleLocalVideoMuted,
  toggleMicrophoneMuted,
  userMediaFeeds,
  activeSpeaker,
  onLeave,
  toggleScreensharing,
  isScreensharing,
  screenshareFeeds,
  roomIdOrAlias,
  unencryptedEventsFromUsers,
  hideHeader,
}: Props) {
  const { t } = useTranslation();
  usePreventScroll();
  const joinRule = useJoinRule(groupCall.room);

  const containerRef1 = useRef<HTMLDivElement | null>(null);
  const [containerRef2, bounds] = useMeasure({ polyfill: ResizeObserver });
  const boundsValid = bounds.height > 0;
  // Merge the refs so they can attach to the same element
  const containerRef = useCallback(
    (el: HTMLDivElement) => {
      containerRef1.current = el;
      containerRef2(el);
    },
    [containerRef1, containerRef2]
  );

  const { layout, setLayout } = useVideoGridLayout(screenshareFeeds.length > 0);
  const { toggleFullscreen, fullscreenParticipant } =
    useFullscreen(containerRef1);

  const [spatialAudio] = useSpatialAudio();

  const [audioContext, audioDestination, audioRef] = useAudioContext();
  const { audioOutput } = useMediaHandler();
  const [showInspector] = useShowInspector();

  const { modalState: feedbackModalState, modalProps: feedbackModalProps } =
    useModalTriggerState();

  useAudioOutputDevice(audioRef, audioOutput);

  const { hideScreensharing } = useUrlParams();

  const makeConnectionStatesMap = useCallback(() => {
    const newConnStates = new Map<string, ConnectionState>();
    for (const participant of participants) {
      const userCall = groupCall.getCallByUserId(participant.userId);
      const feed = userMediaFeeds.find((f) => f.userId === participant.userId);
      let connectionState = ConnectionState.ESTABLISHING_CALL;
      if (feed && feed.isLocal()) {
        connectionState = ConnectionState.CONNECTED;
      } else if (userCall) {
        if (userCall.state === CallState.Connected) {
          connectionState = ConnectionState.CONNECTED;
        } else if (userCall.state === CallState.Connecting) {
          connectionState = ConnectionState.WAIT_MEDIA;
        }
      }
      newConnStates.set(participant.userId, connectionState);
    }
    return newConnStates;
  }, [groupCall, participants, userMediaFeeds]);

  const [connStates, setConnStates] = useState(
    new Map<string, ConnectionState>()
  );

  const updateConnectionStates = useCallback(() => {
    setConnStates(makeConnectionStatesMap());
  }, [setConnStates, makeConnectionStatesMap]);

  useEffect(() => {
    for (const call of calls) {
      call.on(CallEvent.State, updateConnectionStates);
    }

    return () => {
      for (const call of calls) {
        call.off(CallEvent.State, updateConnectionStates);
      }
    };
  }, [calls, updateConnectionStates]);

  useEffect(() => {
    widget?.api.transport.send(
      layout === "freedom"
        ? ElementWidgetActions.TileLayout
        : ElementWidgetActions.SpotlightLayout,
      {}
    );
  }, [layout]);

  useEffect(() => {
    if (widget) {
      const onTileLayout = async (ev: CustomEvent<IWidgetApiRequest>) => {
        setLayout("freedom");
        await widget.api.transport.reply(ev.detail, {});
      };
      const onSpotlightLayout = async (ev: CustomEvent<IWidgetApiRequest>) => {
        setLayout("spotlight");
        await widget.api.transport.reply(ev.detail, {});
      };

      widget.lazyActions.on(ElementWidgetActions.TileLayout, onTileLayout);
      widget.lazyActions.on(
        ElementWidgetActions.SpotlightLayout,
        onSpotlightLayout
      );

      return () => {
        widget.lazyActions.off(ElementWidgetActions.TileLayout, onTileLayout);
        widget.lazyActions.off(
          ElementWidgetActions.SpotlightLayout,
          onSpotlightLayout
        );
      };
    }
  }, [setLayout]);

  const items = useMemo(() => {
    const tileDescriptors: TileDescriptor[] = [];

    // one tile for each participants, to start with (we want a tile for everyone we
    // think should be in the call, even if we don't have a media feed for them yet)
    for (const p of participants) {
      const userMediaFeed = userMediaFeeds.find((f) => f.userId === p.userId);

      // NB. this assumes that the same user can't join more than once from multiple
      // devices, but the participants are just RoomMembers, so this assumption is baked
      // into GroupCall itself.
      tileDescriptors.push({
        id: p.userId,
        member: p,
        callFeed: userMediaFeed,
        focused: screenshareFeeds.length === 0 && p.userId === activeSpeaker,
        isLocal: p.userId === client.getUserId(),
        presenter: false,
        connectionState: connStates.get(p.userId),
      });
    }

    PosthogAnalytics.instance.eventCallEnded.cacheParticipantCountChanged(
      participants.length
    );
    // add the screenshares too
    for (const screenshareFeed of screenshareFeeds) {
      const userMediaItem = tileDescriptors.find(
        (item) => item.member.userId === screenshareFeed.userId
      );

      if (userMediaItem) {
        userMediaItem.presenter = true;
      }

      tileDescriptors.push({
        id: screenshareFeed.stream.id,
        member: screenshareFeed.getMember()!,
        callFeed: screenshareFeed,
        focused: true,
        isLocal: screenshareFeed.isLocal(),
        presenter: false,
        connectionState: ConnectionState.CONNECTED, // by definition since the screen shares arrived on the same connection
      });
    }

    return tileDescriptors;
  }, [
    client,
    participants,
    userMediaFeeds,
    activeSpeaker,
    screenshareFeeds,
    connStates,
  ]);

  // The maximised participant: either the participant that the user has
  // manually put in fullscreen, or the focused (active) participant if the
  // window is too small to show everyone
  const maximisedParticipant = useMemo(
    () =>
      fullscreenParticipant ??
      (boundsValid && bounds.height <= 400 && bounds.width <= 400
        ? items.find((item) => item.focused) ??
          items.find((item) => item.callFeed) ??
          null
        : null),
    [fullscreenParticipant, boundsValid, bounds, items]
  );

  const reducedControls = boundsValid && bounds.width <= 400;

  const renderAvatar = useCallback(
    (roomMember: RoomMember, width: number, height: number) => {
      const avatarUrl = roomMember.getMxcAvatarUrl();
      const size = Math.round(Math.min(width, height) / 2);

      return (
        <Avatar
          key={roomMember.userId}
          size={size}
          src={avatarUrl ?? undefined}
          fallback={roomMember.name.slice(0, 1).toUpperCase()}
          className={styles.avatar}
        />
      );
    },
    []
  );

  const prefersReducedMotion = usePrefersReducedMotion();

  const renderContent = (): JSX.Element => {
    if (items.length === 0) {
      return (
        <div className={styles.centerMessage}>
          <p>{t("Waiting for other participants…")}</p>
        </div>
      );
    }
    if (maximisedParticipant) {
      return (
        <VideoTileContainer
          height={bounds.height}
          width={bounds.width}
          key={maximisedParticipant.id}
          item={maximisedParticipant}
          getAvatar={renderAvatar}
          audioContext={audioContext}
          audioDestination={audioDestination}
          disableSpeakingIndicator={true}
          maximised={Boolean(maximisedParticipant)}
          fullscreen={maximisedParticipant === fullscreenParticipant}
          onFullscreen={toggleFullscreen}
        />
      );
    }

    return (
      <VideoGrid
        items={items}
        layout={layout}
        disableAnimations={prefersReducedMotion || isSafari}
      >
        {({
          item,
          ...rest
        }: {
          item: TileDescriptor;
          [x: string]: unknown;
        }) => (
          <VideoTileContainer
            key={item.id}
            item={item}
            getAvatar={renderAvatar}
            audioContext={audioContext}
            audioDestination={audioDestination}
            disableSpeakingIndicator={items.length < 3}
            maximised={false}
            fullscreen={false}
            onFullscreen={toggleFullscreen}
            {...rest}
          />
        )}
      </VideoGrid>
    );
  };

  const {
    modalState: rageshakeRequestModalState,
    modalProps: rageshakeRequestModalProps,
  } = useRageshakeRequestModal(groupCall.room.roomId);

  const containerClasses = classNames(styles.inRoom, {
    [styles.maximised]: maximisedParticipant,
  });

  return (
    <div className={containerClasses} ref={containerRef}>
      <audio ref={audioRef} />
      {(!spatialAudio || maximisedParticipant) && (
        <AudioContainer
          items={items}
          audioContext={audioContext}
          audioDestination={audioDestination}
        />
      )}
      {!hideHeader && !maximisedParticipant && (
        <Header>
          <LeftNav>
            <RoomHeaderInfo roomName={roomName} avatarUrl={avatarUrl} />
            <VersionMismatchWarning
              users={unencryptedEventsFromUsers}
              room={groupCall.room}
            />
          </LeftNav>
          <RightNav>
            <GridLayoutMenu layout={layout} setLayout={setLayout} />
            <UserMenuContainer preventNavigation />
          </RightNav>
        </Header>
      )}
      {renderContent()}
      <div className={styles.footer}>
        <MicButton muted={microphoneMuted} onPress={toggleMicrophoneMuted} />
        <VideoButton muted={localVideoMuted} onPress={toggleLocalVideoMuted} />
        {canScreenshare &&
          !hideScreensharing &&
          !isSafari &&
          !reducedControls && (
            <ScreenshareButton
              enabled={isScreensharing}
              onPress={toggleScreensharing}
            />
          )}
        {!reducedControls && (
          <OverflowMenu
            inCall
            roomIdOrAlias={roomIdOrAlias}
            groupCall={groupCall}
            showInvite={joinRule === JoinRule.Public}
            feedbackModalState={feedbackModalState}
            feedbackModalProps={feedbackModalProps}
          />
        )}
        <HangupButton onPress={onLeave} />
      </div>
      <GroupCallInspector
        client={client}
        groupCall={groupCall}
        show={showInspector}
      />
      {rageshakeRequestModalState.isOpen && (
        <RageshakeRequestModal
          {...rageshakeRequestModalProps}
          roomIdOrAlias={roomIdOrAlias}
        />
      )}
    </div>
  );
}
