/*
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 } from 'react';
import ReactDOM from 'react-dom';
import highlight from 'highlight.js';
import { MatrixEvent } from 'matrix-js-sdk/src/models/event';
import { MsgType } from "matrix-js-sdk/src/@types/event";

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 { toRightOf } from '../../structures/ContextMenu';
import SettingsStore from "../../../settings/SettingsStore";
import ReplyThread from "../elements/ReplyThread";
import { pillifyLinks, unmountPills } from '../../../utils/pillify';
import { IntegrationManagers } from "../../../integrations/IntegrationManagers";
import { isPermalinkHost } from "../../../utils/permalinks/Permalinks";
import { copyPlaintext } from "../../../utils/strings";
import AccessibleTooltipButton from "../elements/AccessibleTooltipButton";
import { replaceableComponent } from "../../../utils/replaceableComponent";
import UIStore from "../../../stores/UIStore";
import { ComposerInsertPayload } from "../../../dispatcher/payloads/ComposerInsertPayload";
import { Action } from "../../../dispatcher/actions";
import { TileShape } from '../rooms/EventTile';
import EditorStateTransfer from "../../../utils/EditorStateTransfer";
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 LinkPreviewWidget from '../rooms/LinkPreviewWidget';

interface IProps {
    /* the MatrixEvent to show */
    mxEvent: MatrixEvent;

    /* a list of words to highlight */
    highlights?: string[];

    /* link URL for the highlights */
    highlightLink?: string;

    /* should show URL previews for this event */
    showUrlPreview?: boolean;

    /* the shape of the tile, used */
    tileShape?: TileShape;

    editState?: EditorStateTransfer;
    replacingEventId?: string;

    /* callback for when our widget has loaded */
    onHeightChanged(): void,
}

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;
}

@replaceableComponent("views.messages.TextualBody")
export default class TextualBody extends React.Component<IProps, IState> {
    private readonly contentRef = createRef<HTMLSpanElement>();

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

    constructor(props) {
        super(props);

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

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

    private applyFormatting(): void {
        const showLineNumbers = SettingsStore.getValue("showCodeLineNumbers");
        this.activateSpoilers([this.contentRef.current]);

        // pillifyLinks BEFORE linkifyElement because plain room/user URLs in the composer
        // are still sent as plaintext URLs. If these are ever pillified in the composer,
        // we should be pillify them here by doing the linkifying BEFORE the pillifying.
        pillifyLinks([this.contentRef.current], this.props.mxEvent, this.pills);
        HtmlUtils.linkifyElement(this.contentRef.current);
        this.calculateUrlPreview();

        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.
                setTimeout(() => {
                    if (this.unmounted) return;
                    for (let i = 0; i < codes.length; i++) {
                        // If the code already has the hljs class we want to skip this.
                        // This happens after the codeblock was edited.
                        if (codes[i].className.includes("hljs")) continue;
                        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.
        const percentageOfViewport = pre.offsetHeight / UIStore.instance.windowHeight * 100;
        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 () => {
            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 () => {
            const copyCode = button.parentElement.getElementsByTagName("code")[0];
            const successful = await copyPlaintext(copyCode.textContent);

            const buttonRect = button.getBoundingClientRect();
            const { close } = ContextMenu.createMenu(GenericTextContextMenu, {
                ...toRightOf(buttonRect, 2),
                message: successful ? _t('Copied!') : _t('Failed to 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;
        pre.innerHTML = '<span class="mx_EventTile_lineNumbers"></span>' + pre.innerHTML + '<span></span>';
        const lineNumbers = pre.getElementsByClassName("mx_EventTile_lineNumbers")[0];
        // Iterate through lines starting with 1 (number of the first line is 1)
        for (let i = 1; i <= number; i++) {
            lineNumbers.innerHTML += '<span class="mx_EventTile_lineNumber">' + i + '</span>';
        }
    }

    private highlightCode(code: HTMLElement): void {
        if (SettingsStore.getValue("enableSyntaxHighlightLanguageDetection")) {
            highlight.highlightBlock(code);
        } else {
            // Only syntax highlight if there's a class starting with language-
            const classes = code.className.split(/\s+/).filter(function(cl) {
                return cl.startsWith('language-') && !cl.startsWith('language-_');
            });

            if (classes.length != 0) {
                highlight.highlightBlock(code);
            }
        }
    }

    componentDidUpdate(prevProps) {
        if (!this.props.editState) {
            const stoppedEditing = prevProps.editState && !this.props.editState;
            const messageWasEdited = prevProps.replacingEventId !== this.props.replacingEventId;
            if (messageWasEdited || stoppedEditing) {
                this.applyFormatting();
            }
        }
    }

    componentWillUnmount() {
        this.unmounted = true;
        unmountPills(this.pills);
    }

    shouldComponentUpdate(nextProps, nextState) {
        //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);
    }

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

        if (this.props.showUrlPreview) {
            // 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 after stripping hashes as they don't affect the preview
                // using a set here maintains the order
                links = Array.from(new Set(links.map(link => {
                    const url = new URL(link);
                    url.hash = "";
                    return url.toString();
                })));

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

                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
        if (!node.getAttribute("href").startsWith("http://") &&
            !node.getAttribute("href").startsWith("https://")) {
            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.indexOf("/") > -1) {
            return true;
        } else {
            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 (isPermalinkHost(host)) return false;

            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<ComposerInsertPayload>({
            action: Action.ComposerInsert,
            userId: mxEvent.getSender(),
        });
    };

    public getEventTileOps = () => ({
        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.createTrackedDialog('Add an integration', '', QuestionDialog, {
                title: _t("Add an Integration"),
                description:
                    <div>
                        { _t("You are about to be taken to a third-party site so you can " +
                            "authenticate your account for use with %(integrationsUrl)s. " +
                            "Do you wish to continue?", { integrationsUrl: integrationsUrl }) }
                    </div>,
                button: _t("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() {
        const date = this.props.mxEvent.replacingEventDate();
        const dateString = date && formatDate(date);

        const tooltip = <div>
            <div className="mx_Tooltip_title">
                {_t("Edited at %(date)s", { date: dateString })}
            </div>
            <div className="mx_Tooltip_sub">
                {_t("Click to view edits")}
            </div>
        </div>;

        return (
            <AccessibleTooltipButton
                className="mx_EventTile_edited"
                onClick={this.openHistoryDialog}
                title={_t("Edited at %(date)s. Click to view edits.", { date: dateString })}
                tooltip={tooltip}
            >
                <span>{`(${_t("edited")})`}</span>
            </AccessibleTooltipButton>
        );
    }

    render() {
        if (this.props.editState) {
            return <EditMessageComposer editState={this.props.editState} className="mx_EventTile_content" />;
        }
        const mxEvent = this.props.mxEvent;
        const content = mxEvent.getContent();

        // only strip reply if this is the original replying event, edits thereafter do not have the fallback
        const stripReply = !mxEvent.replacingEvent() && !!ReplyThread.getParentEventId(mxEvent);
        let body = HtmlUtils.bodyToHtml(content, this.props.highlights, {
            disableBigEmoji: content.msgtype === MsgType.Emote
                || !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.highlightLink) {
            body = <a href={this.props.highlightLink}>{ body }</a>;
        } else if (content.data && typeof content.data["org.matrix.neb.starter_link"] === "string") {
            body = <a href="#"
                onClick={this.onStarterLinkClick.bind(this, content.data["org.matrix.neb.starter_link"])}
            >{ body }</a>;
        }

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

        switch (content.msgtype) {
            case MsgType.Emote:
                return (
                    <span className="mx_MEmoteBody mx_EventTile_content">
                        *&nbsp;
                        <span
                            className="mx_MEmoteBody_sender"
                            onClick={this.onEmoteSenderClick}
                        >
                            { mxEvent.sender ? mxEvent.sender.name : mxEvent.getSender() }
                        </span>
                        &nbsp;
                        { body }
                        { widgets }
                    </span>
                );
            case MsgType.Notice:
                return (
                    <span className="mx_MNoticeBody mx_EventTile_content">
                        { body }
                        { widgets }
                    </span>
                );
            default: // including "m.text"
                return (
                    <span className="mx_MTextBody mx_EventTile_content">
                        { body }
                        { widgets }
                    </span>
                );
        }
    }
}
