/*
Copyright 2024 New Vector Ltd.
Copyright 2021-2023 The Matrix.org Foundation C.I.C.

SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only OR LicenseRef-Element-Commercial
Please see LICENSE files in the repository root for full details.
*/

import React, { type JSX, createRef, type KeyboardEvent } from "react";
import {
    type Thread,
    THREAD_RELATION_TYPE,
    ThreadEvent,
    type Room,
    RoomEvent,
    type IEventRelation,
    type MatrixEvent,
} from "matrix-js-sdk/src/matrix";
import { logger } from "matrix-js-sdk/src/logger";
import classNames from "classnames";

import BaseCard from "../views/right_panel/BaseCard";
import { RightPanelPhases } from "../../stores/right-panel/RightPanelStorePhases";
import type ResizeNotifier from "../../utils/ResizeNotifier";
import MessageComposer from "../views/rooms/MessageComposer";
import { type RoomPermalinkCreator } from "../../utils/permalinks/Permalinks";
import { Layout } from "../../settings/enums/Layout";
import TimelinePanel from "./TimelinePanel";
import dis from "../../dispatcher/dispatcher";
import { type ActionPayload } from "../../dispatcher/payloads";
import { Action } from "../../dispatcher/actions";
import { type E2EStatus } from "../../utils/ShieldUtils";
import EditorStateTransfer from "../../utils/EditorStateTransfer";
import RoomContext, { TimelineRenderingType } from "../../contexts/RoomContext";
import ContentMessages from "../../ContentMessages";
import UploadBar from "./UploadBar";
import { _t } from "../../languageHandler";
import ThreadListContextMenu from "../views/context_menus/ThreadListContextMenu";
import RightPanelStore from "../../stores/right-panel/RightPanelStore";
import SettingsStore from "../../settings/SettingsStore";
import { type ViewRoomPayload } from "../../dispatcher/payloads/ViewRoomPayload";
import FileDropTarget from "./FileDropTarget";
import { getKeyBindingsManager } from "../../KeyBindingsManager";
import { KeyBindingAction } from "../../accessibility/KeyboardShortcuts";
import Measured from "../views/elements/Measured";
import PosthogTrackers from "../../PosthogTrackers";
import { type ButtonEvent } from "../views/elements/AccessibleButton";
import Spinner from "../views/elements/Spinner";
import { type ComposerInsertPayload, ComposerType } from "../../dispatcher/payloads/ComposerInsertPayload";
import Heading from "../views/typography/Heading";
import { type ThreadPayload } from "../../dispatcher/payloads/ThreadPayload";
import { ScopedRoomContextProvider } from "../../contexts/ScopedRoomContext.tsx";
import { RoomUploadContextProvider } from "../../viewmodels/room/RoomUploadViewModel.tsx";
import { EventPresentationContextProvider } from "../../utils/EventPresentationContextProvider";

interface IProps {
    room: Room;
    onClose: () => void;
    resizeNotifier: ResizeNotifier;
    mxEvent: MatrixEvent;
    permalinkCreator?: RoomPermalinkCreator;
    e2eStatus?: E2EStatus;
    initialEvent?: MatrixEvent;
    isInitialEventHighlighted?: boolean;
    initialEventScrollIntoView?: boolean;
}

interface IState {
    thread?: Thread;
    lastReply?: MatrixEvent | null;
    layout: Layout;
    editState?: EditorStateTransfer;
    replyToEvent?: MatrixEvent;
    narrow: boolean;
}

export default class ThreadView extends React.Component<IProps, IState> {
    public static contextType = RoomContext;
    declare public context: React.ContextType<typeof RoomContext>;

    private dispatcherRef?: string;
    private layoutWatcherRef?: string;
    private timelinePanel = createRef<TimelinePanel>();
    private card = createRef<HTMLDivElement>();

    // Set by setEventId in ctor.
    private eventId!: string;

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

        this.setEventId(this.props.mxEvent);
        const thread = this.props.room.getThread(this.eventId) ?? undefined;

        this.state = {
            layout: SettingsStore.getValue("layout"),
            narrow: false,
            thread,
            lastReply: thread?.lastReply((ev: MatrixEvent) => {
                return ev.isRelation(THREAD_RELATION_TYPE.name) && !ev.status;
            }),
        };
    }

    public componentDidMount(): void {
        this.setupThreadListeners(this.state.thread);

        this.layoutWatcherRef = SettingsStore.watchSetting("layout", null, (...[, , , value]) =>
            this.setState({ layout: value as Layout }),
        );

        if (this.state.thread) {
            this.postThreadUpdate(this.state.thread);
        }

        this.setupThread(this.props.mxEvent);
        this.dispatcherRef = dis.register(this.onAction);

        this.props.room.on(ThreadEvent.New, this.onNewThread);
    }

    public componentWillUnmount(): void {
        dis.unregister(this.dispatcherRef);
        const roomId = this.props.mxEvent.getRoomId();
        SettingsStore.unwatchSetting(this.layoutWatcherRef);

        const hasRoomChanged = this.context.roomViewStore.getRoomId() !== roomId;
        if (this.props.initialEvent && !hasRoomChanged) {
            dis.dispatch<ViewRoomPayload>({
                action: Action.ViewRoom,
                room_id: this.props.room.roomId,
                metricsTrigger: undefined, // room doesn't change
            });
        }

        dis.dispatch<ThreadPayload>({
            action: Action.ViewThread,
            thread_id: null,
        });

        this.state.thread?.off(ThreadEvent.NewReply, this.updateThreadRelation);
        this.props.room.off(RoomEvent.LocalEchoUpdated, this.updateThreadRelation);
        this.props.room.removeListener(ThreadEvent.New, this.onNewThread);
    }

    public componentDidUpdate(prevProps: IProps): void {
        if (prevProps.mxEvent !== this.props.mxEvent) {
            this.setEventId(this.props.mxEvent);
            this.setupThread(this.props.mxEvent);
        }

        if (prevProps.room !== this.props.room) {
            RightPanelStore.instance.setCard({ phase: RightPanelPhases.RoomSummary });
        }
    }

    private setEventId(event: MatrixEvent): void {
        if (!event.getId()) {
            throw new Error("Got thread event without id");
        }

        this.eventId = event.getId()!;
    }

    private onAction = (payload: ActionPayload): void => {
        if (payload.phase == RightPanelPhases.ThreadView && payload.event) {
            this.setupThread(payload.event);
        }
        switch (payload.action) {
            case Action.ComposerInsert: {
                const insertPayload = payload as ComposerInsertPayload;
                if (insertPayload.composerType) break;
                if (insertPayload.timelineRenderingType !== TimelineRenderingType.Thread) break;

                // re-dispatch to the correct composer
                dis.dispatch<ComposerInsertPayload>({
                    ...insertPayload,
                    timelineRenderingType: TimelineRenderingType.Thread,
                    composerType: this.state.editState ? ComposerType.Edit : ComposerType.Send,
                });
                break;
            }

            case Action.EditEvent:
                // Quit early if it's not a thread context
                if (payload.timelineRenderingType !== TimelineRenderingType.Thread) return;
                // Quit early if that's not a thread event
                if (payload.event && !payload.event.getThread()) return;
                this.setState(
                    {
                        editState: payload.event ? new EditorStateTransfer(payload.event) : undefined,
                    },
                    () => {
                        if (payload.event) {
                            this.timelinePanel.current?.scrollToEventIfNeeded(payload.event.getId());
                        }
                    },
                );
                break;
            case "reply_to_event":
                if (payload.context === TimelineRenderingType.Thread) {
                    this.setState({
                        replyToEvent: payload.event,
                    });
                }
                break;
            default:
                break;
        }
    };

    private setupThread = (mxEv: MatrixEvent): void => {
        /** presence of event Id has been ensured by {@link setEventId} */
        const eventId = mxEv.getId()!;

        let thread = this.props.room.getThread(eventId);

        if (!thread) {
            const events = [];
            // if the event is still being sent, don't include it in the Thread yet - otherwise the timeline panel
            // will attempt to show it twice (once as a regular event, once as a pending event) and everything will
            // blow up
            if (mxEv.status === null) events.push(mxEv);
            thread = this.props.room.createThread(eventId, mxEv, events, true);
        }

        this.updateThread(thread);
    };

    private onNewThread = (thread: Thread): void => {
        if (thread.id === this.props.mxEvent.getId()) {
            this.setupThread(this.props.mxEvent);
        }
    };

    private updateThreadRelation = (): void => {
        this.setState({
            lastReply: this.threadLastReply,
        });
    };

    private get threadLastReply(): MatrixEvent | undefined {
        return (
            this.state.thread?.lastReply((ev: MatrixEvent) => {
                return ev.isRelation(THREAD_RELATION_TYPE.name) && !ev.status;
            }) ?? undefined
        );
    }

    private updateThread = (thread?: Thread): void => {
        if (this.state.thread === thread) return;

        this.setupThreadListeners(thread, this.state.thread);
        if (thread) {
            this.setState(
                {
                    thread,
                    lastReply: this.threadLastReply,
                },
                async () => this.postThreadUpdate(thread),
            );
        }
    };

    private async postThreadUpdate(thread: Thread): Promise<void> {
        dis.dispatch<ThreadPayload>({
            action: Action.ViewThread,
            thread_id: thread.id,
        });
        thread.emit(ThreadEvent.ViewThread);
        this.updateThreadRelation();
        this.timelinePanel.current?.refreshTimeline(this.props.initialEvent?.getId());
    }

    private setupThreadListeners(thread?: Thread | undefined, oldThread?: Thread | undefined): void {
        if (oldThread) {
            this.state.thread?.off(ThreadEvent.NewReply, this.updateThreadRelation);
            this.props.room.off(RoomEvent.LocalEchoUpdated, this.updateThreadRelation);
        }
        if (thread) {
            thread.on(ThreadEvent.NewReply, this.updateThreadRelation);
            this.props.room.on(RoomEvent.LocalEchoUpdated, this.updateThreadRelation);
        }
    }

    private resetJumpToEvent = (event?: string): void => {
        if (
            this.props.initialEvent &&
            this.props.initialEventScrollIntoView &&
            event === this.props.initialEvent?.getId()
        ) {
            dis.dispatch<ViewRoomPayload>({
                action: Action.ViewRoom,
                room_id: this.props.room.roomId,
                event_id: this.props.initialEvent?.getId(),
                highlighted: this.props.isInitialEventHighlighted,
                scroll_into_view: false,
                replyingToEvent: this.state.replyToEvent,
                metricsTrigger: undefined, // room doesn't change
            });
        }
    };

    private onMeasurement = (narrow: boolean): void => {
        this.setState({ narrow });
    };

    private onKeyDown = (ev: KeyboardEvent): void => {
        let handled = false;

        const action = getKeyBindingsManager().getRoomAction(ev);
        switch (action) {
            case KeyBindingAction.UploadFile: {
                dis.dispatch(
                    {
                        action: "upload_file",
                        context: TimelineRenderingType.Thread,
                    },
                    true,
                );
                handled = true;
                break;
            }
        }

        if (handled) {
            ev.stopPropagation();
            ev.preventDefault();
        }
    };

    private get threadRelation(): IEventRelation {
        const relation: IEventRelation = {
            rel_type: THREAD_RELATION_TYPE.name,
            event_id: this.state.thread?.id,
            is_falling_back: true,
        };

        const fallbackEventId = this.state.lastReply?.getId() ?? this.state.thread?.id;
        if (fallbackEventId) {
            relation["m.in_reply_to"] = {
                event_id: fallbackEventId,
            };
        }

        return relation;
    }

    private renderThreadViewHeader = (): JSX.Element => {
        return (
            <div className="mx_BaseCard_header_title">
                <Heading size="4" className="mx_BaseCard_header_title_heading">
                    {_t("common|thread")}
                </Heading>
                <ThreadListContextMenu mxEvent={this.props.mxEvent} permalinkCreator={this.props.permalinkCreator} />
            </div>
        );
    };

    public render(): React.ReactNode {
        const highlightedEventId = this.props.isInitialEventHighlighted ? this.props.initialEvent?.getId() : undefined;

        const threadRelation = this.threadRelation;

        let timeline: JSX.Element | null;
        if (this.state.thread) {
            if (this.props.initialEvent && this.props.initialEvent.getRoomId() !== this.state.thread.roomId) {
                logger.warn(
                    "ThreadView attempting to render TimelinePanel with mismatched initialEvent",
                    this.state.thread.roomId,
                    this.props.initialEvent.getRoomId(),
                    this.props.initialEvent.getId(),
                );
            }

            const layout = this.state.layout === Layout.Bubble ? Layout.Bubble : Layout.Group;

            timeline = (
                <>
                    <FileDropTarget parent={this.card.current} />
                    <EventPresentationContextProvider layout={layout}>
                        <TimelinePanel
                            key={this.state.thread.id}
                            ref={this.timelinePanel}
                            showReadReceipts={this.context.showReadReceipts}
                            manageReadReceipts={true}
                            manageReadMarkers={true}
                            sendReadReceiptOnLoad={true}
                            timelineSet={this.state.thread.timelineSet}
                            showUrlPreview={this.context.showUrlPreview}
                            // ThreadView doesn't support IRC layout at this time
                            layout={layout}
                            hideThreadedMessages={false}
                            hidden={false}
                            showReactions={true}
                            className="mx_RoomView_messagePanel"
                            permalinkCreator={this.props.permalinkCreator}
                            membersLoaded={true}
                            editState={this.state.editState}
                            eventId={this.props.initialEvent?.getId()}
                            highlightedEventId={highlightedEventId}
                            eventScrollIntoView={this.props.initialEventScrollIntoView}
                            onEventScrolledIntoView={this.resetJumpToEvent}
                        />
                    </EventPresentationContextProvider>
                </>
            );
        } else {
            timeline = (
                <div className="mx_RoomView_messagePanelSpinner">
                    <Spinner />
                </div>
            );
        }

        return (
            <ScopedRoomContextProvider
                {...this.context}
                timelineRenderingType={TimelineRenderingType.Thread}
                threadId={this.state.thread?.id}
                liveTimeline={this.state?.thread?.timelineSet?.getLiveTimeline()}
                narrow={this.state.narrow}
            >
                <RoomUploadContextProvider threadRelation={this.threadRelation}>
                    <BaseCard
                        className={classNames("mx_ThreadView mx_ThreadPanel", {
                            mx_ThreadView_narrow: this.state.narrow,
                        })}
                        onClose={this.props.onClose}
                        withoutScrollContainer={true}
                        header={this.renderThreadViewHeader()}
                        ref={this.card}
                        onKeyDown={this.onKeyDown}
                        onBack={(ev: ButtonEvent) => {
                            PosthogTrackers.trackInteraction("WebThreadViewBackButton", ev);
                        }}
                    >
                        <Measured breakpoint={400} sensor={this.card} onMeasurement={this.onMeasurement} />
                        <div className="mx_ThreadView_timelinePanelWrapper">{timeline}</div>

                        {ContentMessages.sharedInstance().getCurrentUploads(threadRelation).length > 0 && (
                            <UploadBar room={this.props.room} relation={threadRelation} />
                        )}

                        {this.state.thread?.timelineSet && (
                            <MessageComposer
                                room={this.props.room}
                                resizeNotifier={this.props.resizeNotifier}
                                relation={threadRelation}
                                replyToEvent={this.state.replyToEvent}
                                permalinkCreator={this.props.permalinkCreator}
                                e2eStatus={this.props.e2eStatus}
                                compact={true}
                            />
                        )}
                    </BaseCard>
                </RoomUploadContextProvider>
            </ScopedRoomContextProvider>
        );
    }
}
