/*
Copyright 2021 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, {RefObject, useContext, useMemo, useRef, useState} from "react";
import {EventType, RoomType} from "matrix-js-sdk/src/@types/event";
import {Room} from "matrix-js-sdk/src/models/room";
import {EventSubscription} from "fbemitter";

import MatrixClientContext from "../../contexts/MatrixClientContext";
import RoomAvatar from "../views/avatars/RoomAvatar";
import {_t} from "../../languageHandler";
import AccessibleButton from "../views/elements/AccessibleButton";
import RoomName from "../views/elements/RoomName";
import RoomTopic from "../views/elements/RoomTopic";
import InlineSpinner from "../views/elements/InlineSpinner";
import {inviteMultipleToRoom, showRoomInviteDialog} from "../../RoomInvite";
import {useRoomMembers} from "../../hooks/useRoomMembers";
import createRoom, {IOpts, Preset} from "../../createRoom";
import Field from "../views/elements/Field";
import {useEventEmitter} from "../../hooks/useEventEmitter";
import withValidation from "../views/elements/Validation";
import * as Email from "../../email";
import defaultDispatcher from "../../dispatcher/dispatcher";
import {Action} from "../../dispatcher/actions";
import ResizeNotifier from "../../utils/ResizeNotifier"
import MainSplit from './MainSplit';
import ErrorBoundary from "../views/elements/ErrorBoundary";
import {ActionPayload} from "../../dispatcher/payloads";
import RightPanel from "./RightPanel";
import RightPanelStore from "../../stores/RightPanelStore";
import {RightPanelPhases} from "../../stores/RightPanelStorePhases";
import {SetRightPanelPhasePayload} from "../../dispatcher/payloads/SetRightPanelPhasePayload";
import {useStateArray} from "../../hooks/useStateArray";
import SpacePublicShare from "../views/spaces/SpacePublicShare";
import {showAddExistingRooms, showCreateNewRoom, shouldShowSpaceSettings, showSpaceSettings} from "../../utils/space";
import {HierarchyLevel, ISpaceSummaryRoom, showRoom, useSpaceSummary} from "./SpaceRoomDirectory";
import AutoHideScrollbar from "./AutoHideScrollbar";
import MemberAvatar from "../views/avatars/MemberAvatar";
import {useStateToggle} from "../../hooks/useStateToggle";
import SpaceStore from "../../stores/SpaceStore";

interface IProps {
    space: Room;
    justCreatedOpts?: IOpts;
    resizeNotifier: ResizeNotifier;
    onJoinButtonClicked(): void;
    onRejectButtonClicked(): void;
}

interface IState {
    phase: Phase;
    showRightPanel: boolean;
    myMembership: string;
}

enum Phase {
    Landing,
    PublicCreateRooms,
    PublicShare,
    PrivateScope,
    PrivateInvite,
    PrivateCreateRooms,
    PrivateExistingRooms,
}

const RoomMemberCount = ({ room, children }) => {
    const members = useRoomMembers(room);
    const count = members.length;

    if (children) return children(count);
    return count;
};

const useMyRoomMembership = (room: Room) => {
    const [membership, setMembership] = useState(room.getMyMembership());
    useEventEmitter(room, "Room.myMembership", () => {
        setMembership(room.getMyMembership());
    });
    return membership;
};

const SpacePreview = ({ space, onJoinButtonClicked, onRejectButtonClicked }) => {
    const cli = useContext(MatrixClientContext);
    const myMembership = useMyRoomMembership(space);

    const [busy, setBusy] = useState(false);

    let inviterSection;
    let joinButtons;
    if (myMembership === "invite") {
        const inviteSender = space.getMember(cli.getUserId())?.events.member?.getSender();
        const inviter = inviteSender && space.getMember(inviteSender);

        if (inviteSender) {
            inviterSection = <div className="mx_SpaceRoomView_preview_inviter">
                <MemberAvatar member={inviter} width={32} height={32} />
                <div>
                    <div className="mx_SpaceRoomView_preview_inviter_name">
                        { _t("<inviter/> invites you", {}, {
                            inviter: () => <b>{ inviter.name || inviteSender }</b>,
                        }) }
                    </div>
                    { inviter ? <div className="mx_SpaceRoomView_preview_inviter_mxid">
                        { inviteSender }
                    </div> : null }
                </div>
            </div>;
        }

        joinButtons = <>
            <AccessibleButton
                kind="secondary"
                onClick={() => {
                    setBusy(true);
                    onRejectButtonClicked();
                }}
            >
                { _t("Reject") }
            </AccessibleButton>
            <AccessibleButton
                kind="primary"
                onClick={() => {
                    setBusy(true);
                    onJoinButtonClicked();
                }}
            >
                { _t("Accept") }
            </AccessibleButton>
        </>;
    } else {
        joinButtons = (
            <AccessibleButton
                kind="primary"
                onClick={() => {
                    setBusy(true);
                    onJoinButtonClicked();
                }}
            >
                { _t("Join") }
            </AccessibleButton>
        )
    }

    if (busy) {
        joinButtons = <InlineSpinner />;
    }

    let visibilitySection;
    if (space.getJoinRule() === "public") {
        visibilitySection = <span className="mx_SpaceRoomView_preview_info_public">
            { _t("Public space") }
        </span>;
    } else {
        visibilitySection = <span className="mx_SpaceRoomView_preview_info_private">
            { _t("Private space") }
        </span>;
    }

    return <div className="mx_SpaceRoomView_preview">
        { inviterSection }
        <RoomAvatar room={space} height={80} width={80} viewAvatarOnClick={true} />
        <h1 className="mx_SpaceRoomView_preview_name">
            <RoomName room={space} />
        </h1>
        <div className="mx_SpaceRoomView_preview_info">
            { visibilitySection }
            <RoomMemberCount room={space}>
                {(count) => count > 0 ? (
                    <AccessibleButton
                        className="mx_SpaceRoomView_preview_memberCount"
                        kind="link"
                        onClick={() => {
                            defaultDispatcher.dispatch<SetRightPanelPhasePayload>({
                                action: Action.SetRightPanelPhase,
                                phase: RightPanelPhases.RoomMemberList,
                                refireParams: { space },
                            });
                        }}
                    >
                        { _t("%(count)s members", { count }) }
                    </AccessibleButton>
                ) : null}
            </RoomMemberCount>
        </div>
        <RoomTopic room={space}>
            {(topic, ref) =>
                <div className="mx_SpaceRoomView_preview_topic" ref={ref}>
                    { topic }
                </div>
            }
        </RoomTopic>
        <div className="mx_SpaceRoomView_preview_joinButtons">
            { joinButtons }
        </div>
    </div>;
};

const SpaceLanding = ({ space }) => {
    const cli = useContext(MatrixClientContext);
    const myMembership = useMyRoomMembership(space);
    const userId = cli.getUserId();

    let inviteButton;
    if (myMembership === "join" && space.canInvite(userId)) {
        inviteButton = (
            <AccessibleButton className="mx_SpaceRoomView_landing_inviteButton" onClick={() => {
                showRoomInviteDialog(space.roomId);
            }}>
                { _t("Invite people") }
            </AccessibleButton>
        );
    }

    const canAddRooms = myMembership === "join" && space.currentState.maySendStateEvent(EventType.SpaceChild, userId);

    const [refreshToken, forceUpdate] = useStateToggle(false);

    let addRoomButtons;
    if (canAddRooms) {
        addRoomButtons = <React.Fragment>
            <AccessibleButton className="mx_SpaceRoomView_landing_addButton" onClick={async () => {
                const [added] = await showAddExistingRooms(cli, space);
                if (added) {
                    forceUpdate();
                }
            }}>
                { _t("Add existing rooms & spaces") }
            </AccessibleButton>
            <AccessibleButton className="mx_SpaceRoomView_landing_createButton" onClick={() => {
                showCreateNewRoom(cli, space);
            }}>
                { _t("Create a new room") }
            </AccessibleButton>
        </React.Fragment>;
    }

    let settingsButton;
    if (shouldShowSpaceSettings(cli, space)) {
        settingsButton = <AccessibleButton className="mx_SpaceRoomView_landing_settingsButton" onClick={() => {
            showSpaceSettings(cli, space);
        }}>
            { _t("Settings") }
        </AccessibleButton>;
    }

    const [rooms, relations, viaMap] = useSpaceSummary(cli, space, refreshToken);
    const [roomsMap, numRooms] = useMemo(() => {
        if (!rooms) return [];
        const roomsMap = new Map<string, ISpaceSummaryRoom>(rooms.map(r => [r.room_id, r]));
        const numRooms = rooms.filter(r => r.room_type !== RoomType.Space).length;
        return [roomsMap, numRooms];
    }, [rooms]);

    let previewRooms;
    if (roomsMap) {
        previewRooms = <AutoHideScrollbar className="mx_SpaceRoomDirectory_list">
            <div className="mx_SpaceRoomDirectory_roomCount">
                <h3>{ myMembership === "join" ? _t("Rooms") : _t("Default Rooms")}</h3>
                <span>{ numRooms }</span>
            </div>
            <HierarchyLevel
                spaceId={space.roomId}
                rooms={roomsMap}
                relations={relations}
                parents={new Set()}
                onViewRoomClick={(roomId, autoJoin) => {
                    showRoom(roomsMap.get(roomId), Array.from(viaMap.get(roomId) || []), autoJoin);
                }}
            />
        </AutoHideScrollbar>;
    } else if (!rooms) {
        previewRooms = <InlineSpinner />;
    } else {
        previewRooms = <p>{_t("Your server does not support showing space hierarchies.")}</p>;
    }

    return <div className="mx_SpaceRoomView_landing">
        <RoomAvatar room={space} height={80} width={80} viewAvatarOnClick={true} />
        <div className="mx_SpaceRoomView_landing_name">
            <RoomName room={space}>
                {(name) => {
                    const tags = { name: () => <div className="mx_SpaceRoomView_landing_nameRow">
                        <h1>{ name }</h1>
                        <RoomMemberCount room={space}>
                            {(count) => count > 0 ? (
                                <AccessibleButton
                                    className="mx_SpaceRoomView_landing_memberCount"
                                    kind="link"
                                    onClick={() => {
                                        defaultDispatcher.dispatch<SetRightPanelPhasePayload>({
                                            action: Action.SetRightPanelPhase,
                                            phase: RightPanelPhases.RoomMemberList,
                                            refireParams: { space },
                                        });
                                    }}
                                >
                                    { _t("%(count)s members", { count }) }
                                </AccessibleButton>
                            ) : null}
                        </RoomMemberCount>
                    </div> };
                    if (shouldShowSpaceSettings(cli, space)) {
                        if (space.getJoinRule() === "public") {
                            return _t("Your public space <name/>", {}, tags) as JSX.Element;
                        } else {
                            return _t("Your private space <name/>", {}, tags) as JSX.Element;
                        }
                    }
                    return _t("Welcome to <name/>", {}, tags) as JSX.Element;
                }}
            </RoomName>
        </div>
        <div className="mx_SpaceRoomView_landing_topic">
            <RoomTopic room={space} />
        </div>
        <div className="mx_SpaceRoomView_landing_adminButtons">
            { inviteButton }
            { addRoomButtons }
            { settingsButton }
        </div>

        { previewRooms }
    </div>;
};

const SpaceSetupFirstRooms = ({ space, title, description, onFinished }) => {
    const [busy, setBusy] = useState(false);
    const [error, setError] = useState("");
    const numFields = 3;
    const placeholders = [_t("General"), _t("Random"), _t("Support")];
    // TODO vary default prefills for "Just Me" spaces
    const [roomNames, setRoomName] = useStateArray(numFields, [_t("General"), _t("Random"), ""]);
    const fields = new Array(numFields).fill(0).map((_, i) => {
        const name = "roomName" + i;
        return <Field
            key={name}
            name={name}
            type="text"
            label={_t("Room name")}
            placeholder={placeholders[i]}
            value={roomNames[i]}
            onChange={ev => setRoomName(i, ev.target.value)}
            autoFocus={i === 2}
        />;
    });

    const onNextClick = async () => {
        setError("");
        setBusy(true);
        try {
            await Promise.all(roomNames.map(name => name.trim()).filter(Boolean).map(name => {
                return createRoom({
                    createOpts: {
                        preset: space.getJoinRule() === "public" ? Preset.PublicChat : Preset.PrivateChat,
                        name,
                    },
                    spinner: false,
                    encryption: false,
                    andView: false,
                    inlineErrors: true,
                    parentSpace: space,
                });
            }));
            onFinished();
        } catch (e) {
            console.error("Failed to create initial space rooms", e);
            setError(_t("Failed to create initial space rooms"));
        }
        setBusy(false);
    };

    let onClick = onFinished;
    let buttonLabel = _t("Skip for now");
    if (roomNames.some(name => name.trim())) {
        onClick = onNextClick;
        buttonLabel = busy ? _t("Creating rooms...") : _t("Continue")
    }

    return <div>
        <h1>{ title }</h1>
        <div className="mx_SpaceRoomView_description">{ description }</div>

        { error && <div className="mx_SpaceRoomView_errorText">{ error }</div> }
        { fields }

        <div className="mx_SpaceRoomView_buttons">
            <AccessibleButton
                kind="primary"
                disabled={busy}
                onClick={onClick}
            >
                { buttonLabel }
            </AccessibleButton>
        </div>
    </div>;
};

const SpaceSetupPublicShare = ({ space, onFinished }) => {
    return <div className="mx_SpaceRoomView_publicShare">
        <h1>{ _t("Share %(name)s", { name: space.name }) }</h1>
        <div className="mx_SpaceRoomView_description">
            { _t("It's just you at the moment, it will be even better with others.") }
        </div>

        <SpacePublicShare space={space} />

        <div className="mx_SpaceRoomView_buttons">
            <AccessibleButton kind="primary" onClick={onFinished}>
                { _t("Go to my first room") }
            </AccessibleButton>
        </div>
    </div>;
};

const SpaceSetupPrivateScope = ({ space, onFinished }) => {
    return <div className="mx_SpaceRoomView_privateScope">
        <h1>{ _t("Who are you working with?") }</h1>
        <div className="mx_SpaceRoomView_description">
            { _t("Make sure the right people have access to %(name)s", { name: space.name }) }
        </div>

        <AccessibleButton
            className="mx_SpaceRoomView_privateScope_justMeButton"
            onClick={() => { onFinished(false) }}
        >
            <h3>{ _t("Just me") }</h3>
            <div>{ _t("A private space to organise your rooms") }</div>
        </AccessibleButton>
        <AccessibleButton
            className="mx_SpaceRoomView_privateScope_meAndMyTeammatesButton"
            onClick={() => { onFinished(true) }}
        >
            <h3>{ _t("Me and my teammates") }</h3>
            <div>{ _t("A private space for you and your teammates") }</div>
        </AccessibleButton>
    </div>;
};

const validateEmailRules = withValidation({
    rules: [{
        key: "email",
        test: ({ value }) => !value || Email.looksValid(value),
        invalid: () => _t("Doesn't look like a valid email address"),
    }],
});

const SpaceSetupPrivateInvite = ({ space, onFinished }) => {
    const [busy, setBusy] = useState(false);
    const [error, setError] = useState("");
    const numFields = 3;
    const fieldRefs: RefObject<Field>[] = [useRef(), useRef(), useRef()];
    const [emailAddresses, setEmailAddress] = useStateArray(numFields, "");
    const fields = new Array(numFields).fill(0).map((_, i) => {
        const name = "emailAddress" + i;
        return <Field
            key={name}
            name={name}
            type="text"
            label={_t("Email address")}
            placeholder={_t("Email")}
            value={emailAddresses[i]}
            onChange={ev => setEmailAddress(i, ev.target.value)}
            ref={fieldRefs[i]}
            onValidate={validateEmailRules}
            autoFocus={i === 0}
        />;
    });

    const onNextClick = async () => {
        setError("");
        for (let i = 0; i < fieldRefs.length; i++) {
            const fieldRef = fieldRefs[i];
            const valid = await fieldRef.current.validate({ allowEmpty: true });

            if (valid === false) { // true/null are allowed
                fieldRef.current.focus();
                fieldRef.current.validate({ allowEmpty: true, focused: true });
                return;
            }
        }

        setBusy(true);
        const targetIds = emailAddresses.map(name => name.trim()).filter(Boolean);
        try {
            const result = await inviteMultipleToRoom(space.roomId, targetIds);

            const failedUsers = Object.keys(result.states).filter(a => result.states[a] === "error");
            if (failedUsers.length > 0) {
                console.log("Failed to invite users to space: ", result);
                setError(_t("Failed to invite the following users to your space: %(csvUsers)s", {
                    csvUsers: failedUsers.join(", "),
                }));
            } else {
                onFinished();
            }
        } catch (err) {
            console.error("Failed to invite users to space: ", err);
            setError(_t("We couldn't invite those users. Please check the users you want to invite and try again."));
        }
        setBusy(false);
    };

    let onClick = onFinished;
    let buttonLabel = _t("Skip for now");
    if (emailAddresses.some(name => name.trim())) {
        onClick = onNextClick;
        buttonLabel = busy ? _t("Inviting...") : _t("Continue")
    }

    return <div className="mx_SpaceRoomView_inviteTeammates">
        <h1>{ _t("Invite your teammates") }</h1>
        <div className="mx_SpaceRoomView_description">
            { _t("Make sure the right people have access. You can invite more later.") }
        </div>

        { error && <div className="mx_SpaceRoomView_errorText">{ error }</div> }
        { fields }

        <div className="mx_SpaceRoomView_inviteTeammates_buttons">
            <AccessibleButton
                className="mx_SpaceRoomView_inviteTeammates_inviteDialogButton"
                onClick={() => showRoomInviteDialog(space.roomId)}
            >
                { _t("Invite by username") }
            </AccessibleButton>
        </div>

        <div className="mx_SpaceRoomView_buttons">
            <AccessibleButton kind="primary" disabled={busy} onClick={onClick}>
                { buttonLabel }
            </AccessibleButton>
        </div>
    </div>;
};

export default class SpaceRoomView extends React.PureComponent<IProps, IState> {
    static contextType = MatrixClientContext;

    private readonly creator: string;
    private readonly dispatcherRef: string;
    private readonly rightPanelStoreToken: EventSubscription;

    constructor(props, context) {
        super(props, context);

        let phase = Phase.Landing;

        this.creator = this.props.space.currentState.getStateEvents(EventType.RoomCreate, "")?.getSender();
        const showSetup = this.props.justCreatedOpts && this.context.getUserId() === this.creator;

        if (showSetup) {
            phase = this.props.justCreatedOpts.createOpts.preset === Preset.PublicChat
                ? Phase.PublicCreateRooms : Phase.PrivateScope;
        }

        this.state = {
            phase,
            showRightPanel: RightPanelStore.getSharedInstance().isOpenForRoom,
            myMembership: this.props.space.getMyMembership(),
        };

        this.dispatcherRef = defaultDispatcher.register(this.onAction);
        this.rightPanelStoreToken = RightPanelStore.getSharedInstance().addListener(this.onRightPanelStoreUpdate);
        this.context.on("Room.myMembership", this.onMyMembership);
    }

    componentWillUnmount() {
        defaultDispatcher.unregister(this.dispatcherRef);
        this.rightPanelStoreToken.remove();
        this.context.off("Room.myMembership", this.onMyMembership);
    }

    private onMyMembership = (room: Room, myMembership: string) => {
        if (room.roomId === this.props.space.roomId) {
            this.setState({ myMembership });
        }
    };

    private onRightPanelStoreUpdate = () => {
        this.setState({
            showRightPanel: RightPanelStore.getSharedInstance().isOpenForRoom,
        });
    };

    private onAction = (payload: ActionPayload) => {
        if (payload.action !== Action.ViewUser && payload.action !== "view_3pid_invite") return;

        if (payload.action === Action.ViewUser && payload.member) {
            defaultDispatcher.dispatch<SetRightPanelPhasePayload>({
                action: Action.SetRightPanelPhase,
                phase: RightPanelPhases.SpaceMemberInfo,
                refireParams: {
                    space: this.props.space,
                    member: payload.member,
                },
            });
        } else if (payload.action === "view_3pid_invite" && payload.event) {
            defaultDispatcher.dispatch<SetRightPanelPhasePayload>({
                action: Action.SetRightPanelPhase,
                phase: RightPanelPhases.Space3pidMemberInfo,
                refireParams: {
                    space: this.props.space,
                    event: payload.event,
                },
            });
        } else {
            defaultDispatcher.dispatch<SetRightPanelPhasePayload>({
                action: Action.SetRightPanelPhase,
                phase: RightPanelPhases.SpaceMemberList,
                refireParams: { space: this.props.space },
            });
        }
    };

    private goToFirstRoom = async () => {
        // TODO actually go to the first room

        const childRooms = SpaceStore.instance.getChildRooms(this.props.space.roomId);
        if (childRooms.length) {
            const room = childRooms[0];
            defaultDispatcher.dispatch({
                action: "view_room",
                room_id: room.roomId,
            });
            return;
        }

        let suggestedRooms = SpaceStore.instance.suggestedRooms;
        if (SpaceStore.instance.activeSpace !== this.props.space) {
            // the space store has the suggested rooms loaded for a different space, fetch the right ones
            suggestedRooms = (await SpaceStore.instance.fetchSuggestedRooms(this.props.space, 1)).rooms;
        }

        if (suggestedRooms.length) {
            const room = suggestedRooms[0];
            defaultDispatcher.dispatch({
                action: "view_room",
                room_id: room.room_id,
                oobData: {
                    avatarUrl: room.avatar_url,
                    name: room.name || room.canonical_alias || room.aliases.pop() || _t("Empty room"),
                },
            });
            return;
        }

        this.setState({ phase: Phase.Landing });
    };

    private renderBody() {
        switch (this.state.phase) {
            case Phase.Landing:
                if (this.state.myMembership === "join") {
                    return <SpaceLanding space={this.props.space} />;
                } else {
                    return <SpacePreview
                        space={this.props.space}
                        onJoinButtonClicked={this.props.onJoinButtonClicked}
                        onRejectButtonClicked={this.props.onRejectButtonClicked}
                    />;
                }
            case Phase.PublicCreateRooms:
                return <SpaceSetupFirstRooms
                    space={this.props.space}
                    title={_t("What are some things you want to discuss?")}
                    description={_t("Let's create a room for each of them. " +
                        "You can add more later too, including already existing ones.")}
                    onFinished={() => this.setState({ phase: Phase.PublicShare })}
                />;
            case Phase.PublicShare:
                return <SpaceSetupPublicShare space={this.props.space} onFinished={this.goToFirstRoom} />;

            case Phase.PrivateScope:
                return <SpaceSetupPrivateScope
                    space={this.props.space}
                    onFinished={(invite: boolean) => {
                        this.setState({ phase: invite ? Phase.PrivateInvite : Phase.PrivateCreateRooms });
                    }}
                />;
            case Phase.PrivateInvite:
                return <SpaceSetupPrivateInvite
                    space={this.props.space}
                    onFinished={() => this.setState({ phase: Phase.PrivateCreateRooms })}
                />;
            case Phase.PrivateCreateRooms:
                return <SpaceSetupFirstRooms
                    space={this.props.space}
                    title={_t("What projects are you working on?")}
                    description={_t("We'll create rooms for each of them. " +
                        "You can add more later too, including already existing ones.")}
                    onFinished={() => this.setState({ phase: Phase.Landing })}
                />;
        }
    }

    render() {
        const rightPanel = this.state.showRightPanel && this.state.phase === Phase.Landing
            ? <RightPanel room={this.props.space} resizeNotifier={this.props.resizeNotifier} />
            : null;

        return <main className="mx_SpaceRoomView">
            <ErrorBoundary>
                <MainSplit panel={rightPanel} resizeNotifier={this.props.resizeNotifier}>
                    { this.renderBody() }
                </MainSplit>
            </ErrorBoundary>
        </main>;
    }
}