/*
Copyright 2015 - 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, { createRef, SyntheticEvent, MouseEvent } from "react";
import ReactDOM from "react-dom";
import { MsgType } from "matrix-js-sdk/src/matrix";
import { TooltipProvider } from "@vector-im/compound-web";

import * as HtmlUtils from "../../../HtmlUtils";
import { formatDate } from "../../../DateUtils";
import Modal from "../../../Modal";
import dis from "../../../dispatcher/dispatcher";
import { _t } from "../../../languageHandler";
import * as ContextMenu from "../../structures/ContextMenu";
import { ChevronFace, toRightOf } from "../../structures/ContextMenu";
import SettingsStore from "../../../settings/SettingsStore";
import { pillifyLinks, unmountPills } from "../../../utils/pillify";
import { tooltipifyLinks, unmountTooltips } from "../../../utils/tooltipify";
import { IntegrationManagers } from "../../../integrations/IntegrationManagers";
import { isPermalinkHost, tryTransformPermalinkToLocalHref } from "../../../utils/permalinks/Permalinks";
import { copyPlaintext } from "../../../utils/strings";
import AccessibleTooltipButton from "../elements/AccessibleTooltipButton";
import UIStore from "../../../stores/UIStore";
import { Action } from "../../../dispatcher/actions";
import GenericTextContextMenu from "../context_menus/GenericTextContextMenu";
import Spoiler from "../elements/Spoiler";
import QuestionDialog from "../dialogs/QuestionDialog";
import MessageEditHistoryDialog from "../dialogs/MessageEditHistoryDialog";
import EditMessageComposer from "../rooms/EditMessageComposer";
import LinkPreviewGroup from "../rooms/LinkPreviewGroup";
import { IBodyProps } from "./IBodyProps";
import RoomContext from "../../../contexts/RoomContext";
import AccessibleButton from "../elements/AccessibleButton";
import { options as linkifyOpts } from "../../../linkify-matrix";
import { getParentEventId } from "../../../utils/Reply";
import { EditWysiwygComposer } from "../rooms/wysiwyg_composer";
import { IEventTileOps } from "../rooms/EventTile";
import { MatrixClientPeg } from "../../../MatrixClientPeg";

const MAX_HIGHLIGHT_LENGTH = 4096;

interface IState {
    // the URLs (if any) to be previewed with a LinkPreviewWidget inside this TextualBody.
    links: string[];

    // track whether the preview widget is hidden
    widgetHidden: boolean;
}

export default class TextualBody extends React.Component<IBodyProps, IState> {
    private readonly contentRef = createRef<HTMLSpanElement>();

    private unmounted = false;
    private pills: Element[] = [];
    private tooltips: Element[] = [];

    public static contextType = RoomContext;
    public context!: React.ContextType<typeof RoomContext>;

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

        this.state = {
            links: [],
            widgetHidden: false,
        };
    }

    public componentDidMount(): void {
        if (!this.props.editState) {
            this.applyFormatting();
        }
    }

    private applyFormatting(): void {
        // Function is only called from render / componentDidMount → contentRef is set
        const content = this.contentRef.current!;

        const showLineNumbers = SettingsStore.getValue("showCodeLineNumbers");
        this.activateSpoilers([content]);

        HtmlUtils.linkifyElement(content);
        pillifyLinks(MatrixClientPeg.safeGet(), [content], this.props.mxEvent, this.pills);

        this.calculateUrlPreview();

        // tooltipifyLinks AFTER calculateUrlPreview because the DOM inside the tooltip
        // container is empty before the internal component has mounted so calculateUrlPreview
        // won't find any anchors
        tooltipifyLinks([content], this.pills, this.tooltips);

        if (this.props.mxEvent.getContent().format === "org.matrix.custom.html") {
            // Handle expansion and add buttons
            const pres = (ReactDOM.findDOMNode(this) as Element).getElementsByTagName("pre");
            if (pres.length > 0) {
                for (let i = 0; i < pres.length; i++) {
                    // If there already is a div wrapping the codeblock we want to skip this.
                    // This happens after the codeblock was edited.
                    if (pres[i].parentElement?.className == "mx_EventTile_pre_container") continue;
                    // Add code element if it's missing since we depend on it
                    if (pres[i].getElementsByTagName("code").length == 0) {
                        this.addCodeElement(pres[i]);
                    }
                    // Wrap a div around <pre> so that the copy button can be correctly positioned
                    // when the <pre> overflows and is scrolled horizontally.
                    const div = this.wrapInDiv(pres[i]);
                    this.handleCodeBlockExpansion(pres[i]);
                    this.addCodeExpansionButton(div, pres[i]);
                    this.addCodeCopyButton(div);
                    if (showLineNumbers) {
                        this.addLineNumbers(pres[i]);
                    }
                }
            }
            // Highlight code
            const codes = (ReactDOM.findDOMNode(this) as Element).getElementsByTagName("code");
            if (codes.length > 0) {
                // Do this asynchronously: parsing code takes time and we don't
                // need to block the DOM update on it.
                window.setTimeout(() => {
                    if (this.unmounted) return;
                    for (let i = 0; i < codes.length; i++) {
                        this.highlightCode(codes[i]);
                    }
                }, 10);
            }
        }
    }

    private addCodeElement(pre: HTMLPreElement): void {
        const code = document.createElement("code");
        code.append(...pre.childNodes);
        pre.appendChild(code);
    }

    private addCodeExpansionButton(div: HTMLDivElement, pre: HTMLPreElement): void {
        // Calculate how many percent does the pre element take up.
        // If it's less than 30% we don't add the expansion button.
        // We also round the number as it sometimes can be 29.99...
        const percentageOfViewport = Math.round((pre.offsetHeight / UIStore.instance.windowHeight) * 100);
        // TODO: additionally show the button if it's an expanded quoted message
        if (percentageOfViewport < 30) return;

        const button = document.createElement("span");
        button.className = "mx_EventTile_button ";
        if (pre.className == "mx_EventTile_collapsedCodeBlock") {
            button.className += "mx_EventTile_expandButton";
        } else {
            button.className += "mx_EventTile_collapseButton";
        }

        button.onclick = async (): Promise<void> => {
            button.className = "mx_EventTile_button ";
            if (pre.className == "mx_EventTile_collapsedCodeBlock") {
                pre.className = "";
                button.className += "mx_EventTile_collapseButton";
            } else {
                pre.className = "mx_EventTile_collapsedCodeBlock";
                button.className += "mx_EventTile_expandButton";
            }

            // By expanding/collapsing we changed
            // the height, therefore we call this
            this.props.onHeightChanged?.();
        };

        div.appendChild(button);
    }

    private addCodeCopyButton(div: HTMLDivElement): void {
        const button = document.createElement("span");
        button.className = "mx_EventTile_button mx_EventTile_copyButton ";

        // Check if expansion button exists. If so we put the copy button to the bottom
        const expansionButtonExists = div.getElementsByClassName("mx_EventTile_button");
        if (expansionButtonExists.length > 0) button.className += "mx_EventTile_buttonBottom";

        button.onclick = async (): Promise<void> => {
            const copyCode = button.parentElement?.getElementsByTagName("code")[0];
            const successful = copyCode?.textContent ? await copyPlaintext(copyCode.textContent) : false;

            const buttonRect = button.getBoundingClientRect();
            const { close } = ContextMenu.createMenu(GenericTextContextMenu, {
                ...toRightOf(buttonRect, 0),
                chevronFace: ChevronFace.None,
                message: successful ? _t("common|copied") : _t("error|failed_copy"),
            });
            button.onmouseleave = close;
        };

        div.appendChild(button);
    }

    private wrapInDiv(pre: HTMLPreElement): HTMLDivElement {
        const div = document.createElement("div");
        div.className = "mx_EventTile_pre_container";

        // Insert containing div in place of <pre> block
        pre.parentNode?.replaceChild(div, pre);
        // Append <pre> block and copy button to container
        div.appendChild(pre);

        return div;
    }

    private handleCodeBlockExpansion(pre: HTMLPreElement): void {
        if (!SettingsStore.getValue("expandCodeByDefault")) {
            pre.className = "mx_EventTile_collapsedCodeBlock";
        }
    }

    private addLineNumbers(pre: HTMLPreElement): void {
        // Calculate number of lines in pre
        const number = pre.innerHTML.replace(/\n(<\/code>)?$/, "").split(/\n/).length;
        const lineNumbers = document.createElement("span");
        lineNumbers.className = "mx_EventTile_lineNumbers";
        // Iterate through lines starting with 1 (number of the first line is 1)
        for (let i = 1; i <= number; i++) {
            const s = document.createElement("span");
            s.textContent = i.toString();
            lineNumbers.appendChild(s);
        }
        pre.prepend(lineNumbers);
        pre.append(document.createElement("span"));
    }

    private async highlightCode(code: HTMLElement): Promise<void> {
        const { default: highlight } = await import("highlight.js");

        if (code.textContent && code.textContent.length > MAX_HIGHLIGHT_LENGTH) {
            console.log(
                "Code block is bigger than highlight limit (" +
                    code.textContent.length +
                    " > " +
                    MAX_HIGHLIGHT_LENGTH +
                    "): not highlighting",
            );
            return;
        }

        let advertisedLang;
        for (const cl of code.className.split(/\s+/)) {
            if (cl.startsWith("language-")) {
                const maybeLang = cl.split("-", 2)[1];
                if (highlight.getLanguage(maybeLang)) {
                    advertisedLang = maybeLang;
                    break;
                }
            }
        }

        if (advertisedLang) {
            // If the code says what language it is, highlight it in that language
            // We don't use highlightElement here because we can't force language detection
            // off. It should use the one we've found in the CSS class but we'd rather pass
            // it in explicitly to make sure.
            code.innerHTML = highlight.highlight(code.textContent ?? "", { language: advertisedLang }).value;
        } else if (
            SettingsStore.getValue("enableSyntaxHighlightLanguageDetection") &&
            code.parentElement instanceof HTMLPreElement
        ) {
            // User has language detection enabled and the code is within a pre
            // we only auto-highlight if the code block is in a pre), so highlight
            // the block with auto-highlighting enabled.
            // We pass highlightjs the text to highlight rather than letting it
            // work on the DOM with highlightElement because that also adds CSS
            // classes to the pre/code element that we don't want (the CSS
            // conflicts with our own).
            code.innerHTML = highlight.highlightAuto(code.textContent ?? "").value;
        }
    }

    public componentDidUpdate(prevProps: Readonly<IBodyProps>): void {
        if (!this.props.editState) {
            const stoppedEditing = prevProps.editState && !this.props.editState;
            const messageWasEdited = prevProps.replacingEventId !== this.props.replacingEventId;
            if (messageWasEdited || stoppedEditing) {
                this.applyFormatting();
            }
        }
    }

    public componentWillUnmount(): void {
        this.unmounted = true;
        unmountPills(this.pills);
        unmountTooltips(this.tooltips);

        this.pills = [];
        this.tooltips = [];
    }

    public shouldComponentUpdate(nextProps: Readonly<IBodyProps>, nextState: Readonly<IState>): boolean {
        //console.info("shouldComponentUpdate: ShowUrlPreview for %s is %s", this.props.mxEvent.getId(), this.props.showUrlPreview);

        // exploit that events are immutable :)
        return (
            nextProps.mxEvent.getId() !== this.props.mxEvent.getId() ||
            nextProps.highlights !== this.props.highlights ||
            nextProps.replacingEventId !== this.props.replacingEventId ||
            nextProps.highlightLink !== this.props.highlightLink ||
            nextProps.showUrlPreview !== this.props.showUrlPreview ||
            nextProps.editState !== this.props.editState ||
            nextState.links !== this.state.links ||
            nextState.widgetHidden !== this.state.widgetHidden ||
            nextProps.isSeeingThroughMessageHiddenForModeration !== this.props.isSeeingThroughMessageHiddenForModeration
        );
    }

    private calculateUrlPreview(): void {
        //console.info("calculateUrlPreview: ShowUrlPreview for %s is %s", this.props.mxEvent.getId(), this.props.showUrlPreview);

        if (this.props.showUrlPreview && this.contentRef.current) {
            // pass only the first child which is the event tile otherwise this recurses on edited events
            let links = this.findLinks([this.contentRef.current]);
            if (links.length) {
                // de-duplicate the links using a set here maintains the order
                links = Array.from(new Set(links));
                this.setState({ links });

                // lazy-load the hidden state of the preview widget from localstorage
                if (window.localStorage) {
                    const hidden = !!window.localStorage.getItem("hide_preview_" + this.props.mxEvent.getId());
                    this.setState({ widgetHidden: hidden });
                }
            } else if (this.state.links.length) {
                this.setState({ links: [] });
            }
        }
    }

    private activateSpoilers(nodes: ArrayLike<Element>): void {
        let node = nodes[0];
        while (node) {
            if (node.tagName === "SPAN" && typeof node.getAttribute("data-mx-spoiler") === "string") {
                const spoilerContainer = document.createElement("span");

                const reason = node.getAttribute("data-mx-spoiler") ?? undefined;
                node.removeAttribute("data-mx-spoiler"); // we don't want to recurse
                const spoiler = (
                    <TooltipProvider>
                        <Spoiler reason={reason} contentHtml={node.outerHTML} />
                    </TooltipProvider>
                );

                ReactDOM.render(spoiler, spoilerContainer);
                node.parentNode?.replaceChild(spoilerContainer, node);

                node = spoilerContainer;
            }

            if (node.childNodes && node.childNodes.length) {
                this.activateSpoilers(node.childNodes as NodeListOf<Element>);
            }

            node = node.nextSibling as Element;
        }
    }

    private findLinks(nodes: ArrayLike<Element>): string[] {
        let links: string[] = [];

        for (let i = 0; i < nodes.length; i++) {
            const node = nodes[i];
            if (node.tagName === "A" && node.getAttribute("href")) {
                if (this.isLinkPreviewable(node)) {
                    links.push(node.getAttribute("href")!);
                }
            } else if (node.tagName === "PRE" || node.tagName === "CODE" || node.tagName === "BLOCKQUOTE") {
                continue;
            } else if (node.children && node.children.length) {
                links = links.concat(this.findLinks(node.children));
            }
        }
        return links;
    }

    private isLinkPreviewable(node: Element): boolean {
        // don't try to preview relative links
        const href = node.getAttribute("href") ?? "";
        if (!href.startsWith("http://") && !href.startsWith("https://")) {
            return false;
        }

        const url = node.getAttribute("href");
        const host = url?.match(/^https?:\/\/(.*?)(\/|$)/)?.[1];

        // never preview permalinks (if anything we should give a smart
        // preview of the room/user they point to: nobody needs to be reminded
        // what the matrix.to site looks like).
        if (!host || isPermalinkHost(host)) return false;

        // as a random heuristic to avoid highlighting things like "foo.pl"
        // we require the linked text to either include a / (either from http://
        // or from a full foo.bar/baz style schemeless URL) - or be a markdown-style
        // link, in which case we check the target text differs from the link value.
        // TODO: make this configurable?
        if (node.textContent?.includes("/")) {
            return true;
        }

        if (node.textContent?.toLowerCase().trim().startsWith(host.toLowerCase())) {
            // it's a "foo.pl" style link
            return false;
        } else {
            // it's a [foo bar](http://foo.com) style link
            return true;
        }
    }

    private onCancelClick = (): void => {
        this.setState({ widgetHidden: true });
        // FIXME: persist this somewhere smarter than local storage
        if (global.localStorage) {
            global.localStorage.setItem("hide_preview_" + this.props.mxEvent.getId(), "1");
        }
        this.forceUpdate();
    };

    private onEmoteSenderClick = (): void => {
        const mxEvent = this.props.mxEvent;
        dis.dispatch({
            action: Action.ComposerInsert,
            userId: mxEvent.getSender(),
            timelineRenderingType: this.context.timelineRenderingType,
        });
    };

    /**
     * This acts as a fallback in-app navigation handler for any body links that
     * were ignored as part of linkification because they were already links
     * to start with (e.g. pills, links in the content).
     */
    private onBodyLinkClick = (e: MouseEvent): void => {
        let target: HTMLLinkElement | null = e.target as HTMLLinkElement;
        // links processed by linkifyjs have their own handler so don't handle those here
        if (target.classList.contains(linkifyOpts.className as string)) return;
        if (target.nodeName !== "A") {
            // Jump to parent as the `<a>` may contain children, e.g. an anchor wrapping an inline code section
            target = target.closest<HTMLLinkElement>("a");
        }
        if (!target) return;

        const localHref = tryTransformPermalinkToLocalHref(target.href);
        if (localHref !== target.href) {
            // it could be converted to a localHref -> therefore handle locally
            e.preventDefault();
            window.location.hash = localHref;
        }
    };

    public getEventTileOps = (): IEventTileOps => ({
        isWidgetHidden: () => {
            return this.state.widgetHidden;
        },

        unhideWidget: () => {
            this.setState({ widgetHidden: false });
            if (global.localStorage) {
                global.localStorage.removeItem("hide_preview_" + this.props.mxEvent.getId());
            }
        },
    });

    private onStarterLinkClick = (starterLink: string, ev: SyntheticEvent): void => {
        ev.preventDefault();
        // We need to add on our scalar token to the starter link, but we may not have one!
        // In addition, we can't fetch one on click and then go to it immediately as that
        // is then treated as a popup!
        // We can get around this by fetching one now and showing a "confirmation dialog" (hurr hurr)
        // which requires the user to click through and THEN we can open the link in a new tab because
        // the window.open command occurs in the same stack frame as the onClick callback.

        const managers = IntegrationManagers.sharedInstance();
        if (!managers.hasManager()) {
            managers.openNoManagerDialog();
            return;
        }

        // Go fetch a scalar token
        const integrationManager = managers.getPrimaryManager();
        const scalarClient = integrationManager?.getScalarClient();
        scalarClient?.connect().then(() => {
            const completeUrl = scalarClient.getStarterLink(starterLink);
            const integrationsUrl = integrationManager!.uiUrl;
            Modal.createDialog(QuestionDialog, {
                title: _t("timeline|scalar_starter_link|dialog_title"),
                description: (
                    <div>
                        {_t("timeline|scalar_starter_link|dialog_description", { integrationsUrl: integrationsUrl })}
                    </div>
                ),
                button: _t("action|continue"),
                onFinished(confirmed) {
                    if (!confirmed) {
                        return;
                    }
                    const width = window.screen.width > 1024 ? 1024 : window.screen.width;
                    const height = window.screen.height > 800 ? 800 : window.screen.height;
                    const left = (window.screen.width - width) / 2;
                    const top = (window.screen.height - height) / 2;
                    const features = `height=${height}, width=${width}, top=${top}, left=${left},`;
                    const wnd = window.open(completeUrl, "_blank", features)!;
                    wnd.opener = null;
                },
            });
        });
    };

    private openHistoryDialog = async (): Promise<void> => {
        Modal.createDialog(MessageEditHistoryDialog, { mxEvent: this.props.mxEvent });
    };

    private renderEditedMarker(): JSX.Element {
        const date = this.props.mxEvent.replacingEventDate();
        const dateString = date && formatDate(date);

        const tooltip = (
            <div>
                <div className="mx_Tooltip_title">{_t("timeline|edits|tooltip_title", { date: dateString })}</div>
                <div className="mx_Tooltip_sub">{_t("timeline|edits|tooltip_sub")}</div>
            </div>
        );

        return (
            <AccessibleTooltipButton
                className="mx_EventTile_edited"
                onClick={this.openHistoryDialog}
                title={_t("timeline|edits|tooltip_label", { date: dateString })}
                tooltip={tooltip}
            >
                <span>{`(${_t("common|edited")})`}</span>
            </AccessibleTooltipButton>
        );
    }

    /**
     * Render a marker informing the user that, while they can see the message,
     * it is hidden for other users.
     */
    private renderPendingModerationMarker(): JSX.Element {
        let text;
        const visibility = this.props.mxEvent.messageVisibility();
        switch (visibility.visible) {
            case true:
                throw new Error("renderPendingModerationMarker should only be applied to hidden messages");
            case false:
                if (visibility.reason) {
                    text = _t("timeline|pending_moderation_reason", { reason: visibility.reason });
                } else {
                    text = _t("timeline|pending_moderation");
                }
                break;
        }
        return <span className="mx_EventTile_pendingModeration">{`(${text})`}</span>;
    }

    public render(): React.ReactNode {
        if (this.props.editState) {
            const isWysiwygComposerEnabled = SettingsStore.getValue("feature_wysiwyg_composer");
            return isWysiwygComposerEnabled ? (
                <EditWysiwygComposer editorStateTransfer={this.props.editState} className="mx_EventTile_content" />
            ) : (
                <EditMessageComposer editState={this.props.editState} className="mx_EventTile_content" />
            );
        }
        const mxEvent = this.props.mxEvent;
        const content = mxEvent.getContent();
        let isNotice = false;
        let isEmote = false;

        // only strip reply if this is the original replying event, edits thereafter do not have the fallback
        const stripReply = !mxEvent.replacingEvent() && !!getParentEventId(mxEvent);
        isEmote = content.msgtype === MsgType.Emote;
        isNotice = content.msgtype === MsgType.Notice;
        let body = HtmlUtils.bodyToHtml(content, this.props.highlights, {
            disableBigEmoji: isEmote || !SettingsStore.getValue<boolean>("TextualBody.enableBigEmoji"),
            // Part of Replies fallback support
            stripReplyFallback: stripReply,
            ref: this.contentRef,
            returnString: false,
        });

        if (this.props.replacingEventId) {
            body = (
                <>
                    {body}
                    {this.renderEditedMarker()}
                </>
            );
        }
        if (this.props.isSeeingThroughMessageHiddenForModeration) {
            body = (
                <>
                    {body}
                    {this.renderPendingModerationMarker()}
                </>
            );
        }

        if (this.props.highlightLink) {
            body = <a href={this.props.highlightLink}>{body}</a>;
        } else if (content.data && typeof content.data["org.matrix.neb.starter_link"] === "string") {
            body = (
                <AccessibleButton
                    kind="link_inline"
                    onClick={this.onStarterLinkClick.bind(this, content.data["org.matrix.neb.starter_link"])}
                >
                    {body}
                </AccessibleButton>
            );
        }

        let widgets;
        if (this.state.links.length && !this.state.widgetHidden && this.props.showUrlPreview) {
            widgets = (
                <LinkPreviewGroup
                    links={this.state.links}
                    mxEvent={this.props.mxEvent}
                    onCancelClick={this.onCancelClick}
                    onHeightChanged={this.props.onHeightChanged}
                />
            );
        }

        if (isEmote) {
            return (
                <div className="mx_MEmoteBody mx_EventTile_content" onClick={this.onBodyLinkClick}>
                    *&nbsp;
                    <span className="mx_MEmoteBody_sender" onClick={this.onEmoteSenderClick}>
                        {mxEvent.sender ? mxEvent.sender.name : mxEvent.getSender()}
                    </span>
                    &nbsp;
                    {body}
                    {widgets}
                </div>
            );
        }
        if (isNotice) {
            return (
                <div className="mx_MNoticeBody mx_EventTile_content" onClick={this.onBodyLinkClick}>
                    {body}
                    {widgets}
                </div>
            );
        }
        return (
            <div className="mx_MTextBody mx_EventTile_content" onClick={this.onBodyLinkClick}>
                {body}
                {widgets}
            </div>
        );
    }
}
