/*
Copyright 2020 The 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 from "react";
import classNames from "classnames";
import { Room } from "matrix-js-sdk/src/models/room";
import { User } from "matrix-js-sdk/src/models/user";
import { MatrixEvent } from "matrix-js-sdk/src/models/event";

import RoomAvatar from "./RoomAvatar";
import NotificationBadge from '../rooms/NotificationBadge';
import { RoomNotificationStateStore } from "../../../stores/notifications/RoomNotificationStateStore";
import { NotificationState } from "../../../stores/notifications/NotificationState";
import { isPresenceEnabled } from "../../../utils/presence";
import { MatrixClientPeg } from "../../../MatrixClientPeg";
import { _t } from "../../../languageHandler";
import TextWithTooltip from "../elements/TextWithTooltip";
import DMRoomMap from "../../../utils/DMRoomMap";
import { replaceableComponent } from "../../../utils/replaceableComponent";

interface IProps {
    room: Room;
    avatarSize: number;
    displayBadge?: boolean;
    forceCount?: boolean;
    oobData?: object;
    viewAvatarOnClick?: boolean;
}

interface IState {
    notificationState?: NotificationState;
    icon: Icon;
}

enum Icon {
    // Note: the names here are used in CSS class names
    None = "NONE", // ... except this one
    Globe = "GLOBE",
    PresenceOnline = "ONLINE",
    PresenceAway = "AWAY",
    PresenceOffline = "OFFLINE",
}

function tooltipText(variant: Icon) {
    switch (variant) {
        case Icon.Globe:
            return _t("This room is public");
        case Icon.PresenceOnline:
            return _t("Online");
        case Icon.PresenceAway:
            return _t("Away");
        case Icon.PresenceOffline:
            return _t("Offline");
    }
}

@replaceableComponent("views.avatars.DecoratedRoomAvatar")
export default class DecoratedRoomAvatar extends React.PureComponent<IProps, IState> {
    private _dmUser: User;
    private isUnmounted = false;
    private isWatchingTimeline = false;

    constructor(props: IProps) {
        super(props);

        this.state = {
            notificationState: RoomNotificationStateStore.instance.getRoomState(this.props.room),
            icon: this.calculateIcon(),
        };
    }

    public componentWillUnmount() {
        this.isUnmounted = true;
        if (this.isWatchingTimeline) this.props.room.off('Room.timeline', this.onRoomTimeline);
        this.dmUser = null; // clear listeners, if any
    }

    private get isPublicRoom(): boolean {
        const joinRules = this.props.room.currentState.getStateEvents("m.room.join_rules", "");
        const joinRule = joinRules && joinRules.getContent().join_rule;
        return joinRule === 'public';
    }

    private get dmUser(): User {
        return this._dmUser;
    }

    private set dmUser(val: User) {
        const oldUser = this._dmUser;
        this._dmUser = val;
        if (oldUser && oldUser !== this._dmUser) {
            oldUser.off('User.currentlyActive', this.onPresenceUpdate);
            oldUser.off('User.presence', this.onPresenceUpdate);
        }
        if (this._dmUser && oldUser !== this._dmUser) {
            this._dmUser.on('User.currentlyActive', this.onPresenceUpdate);
            this._dmUser.on('User.presence', this.onPresenceUpdate);
        }
    }

    private onRoomTimeline = (ev: MatrixEvent, room: Room) => {
        if (this.isUnmounted) return;

        // apparently these can happen?
        if (!room) return;
        if (this.props.room.roomId !== room.roomId) return;

        if (ev.getType() === 'm.room.join_rules' || ev.getType() === 'm.room.member') {
            const newIcon = this.calculateIcon();
            if (newIcon !== this.state.icon) {
                this.setState({ icon: newIcon });
            }
        }
    };

    private onPresenceUpdate = () => {
        if (this.isUnmounted) return;

        const newIcon = this.getPresenceIcon();
        if (newIcon !== this.state.icon) this.setState({ icon: newIcon });
    };

    private getPresenceIcon(): Icon {
        if (!this.dmUser) return Icon.None;

        let icon = Icon.None;

        const isOnline = this.dmUser.currentlyActive || this.dmUser.presence === 'online';
        if (isOnline) {
            icon = Icon.PresenceOnline;
        } else if (this.dmUser.presence === 'offline') {
            icon = Icon.PresenceOffline;
        } else if (this.dmUser.presence === 'unavailable') {
            icon = Icon.PresenceAway;
        }

        return icon;
    }

    private calculateIcon(): Icon {
        let icon = Icon.None;

        // We look at the DMRoomMap and not the tag here so that we don't exclude DMs in Favourites
        const otherUserId = DMRoomMap.shared().getUserIdForRoomId(this.props.room.roomId);
        if (otherUserId && this.props.room.getJoinedMemberCount() === 2) {
            // Track presence, if available
            if (isPresenceEnabled()) {
                if (otherUserId) {
                    this.dmUser = MatrixClientPeg.get().getUser(otherUserId);
                    icon = this.getPresenceIcon();
                }
            }
        } else {
            // Track publicity
            icon = this.isPublicRoom ? Icon.Globe : Icon.None;
            if (!this.isWatchingTimeline) {
                this.props.room.on('Room.timeline', this.onRoomTimeline);
                this.isWatchingTimeline = true;
            }
        }
        return icon;
    }

    public render(): React.ReactNode {
        let badge: React.ReactNode;
        if (this.props.displayBadge) {
            badge = <NotificationBadge
                notification={this.state.notificationState}
                forceCount={this.props.forceCount}
                roomId={this.props.room.roomId}
            />;
        }

        let icon;
        if (this.state.icon !== Icon.None) {
            icon = <TextWithTooltip
                tooltip={tooltipText(this.state.icon)}
                class={`mx_DecoratedRoomAvatar_icon mx_DecoratedRoomAvatar_icon_${this.state.icon.toLowerCase()}`}
            />;
        }

        const classes = classNames("mx_DecoratedRoomAvatar", {
            mx_DecoratedRoomAvatar_cutout: icon,
        });

        return <div className={classes}>
            <RoomAvatar
                room={this.props.room}
                width={this.props.avatarSize}
                height={this.props.avatarSize}
                oobData={this.props.oobData}
                viewAvatarOnClick={this.props.viewAvatarOnClick}
            />
            {icon}
            {badge}
        </div>;
    }
}
