import './Text.css'
import { useMemo, useCallback } from "react";
import { Link } from "react-router-dom";
import ReactMarkdown from "react-markdown";
import { visit, SKIP } from "unist-util-visit";

import { UrlRegex, MentionRegex, InvoiceRegex, HashtagRegex } from "Const";
import { eventLink, hexToBech32 } from "Util";
import Invoice from "Element/Invoice";
import Hashtag from "Element/Hashtag";

import Tag from "Nostr/Tag";
import { MetadataCache } from "State/Users";
import Mention from "Element/Mention";
import HyperText from 'Element/HyperText';
import { HexKey } from 'Nostr';

export type Fragment = string | JSX.Element;

export interface TextFragment {
    body: Fragment[],
    tags: Tag[],
    users: Map<string, MetadataCache>
}

export interface TextProps {
    content: string,
    creator: HexKey,
    tags: Tag[],
    users: Map<string, MetadataCache>
}

export default function Text({ content, tags, creator, users }: TextProps) {

    function extractLinks(fragments: Fragment[]) {
        return fragments.map(f => {
            if (typeof f === "string") {
                return f.split(UrlRegex).map(a => {
                    if (a.startsWith("http")) {
                        return <HyperText link={a} creator={creator} />
                    }
                    return a;
                });
            }
            return f;
        }).flat();
    }

    function extractMentions(frag: TextFragment) {
        return frag.body.map(f => {
            if (typeof f === "string") {
                return f.split(MentionRegex).map((match) => {
                    let matchTag = match.match(/#\[(\d+)\]/);
                    if (matchTag && matchTag.length === 2) {
                        let idx = parseInt(matchTag[1]);
                        let ref = frag.tags?.find(a => a.Index === idx);
                        if (ref) {
                            switch (ref.Key) {
                                case "p": {
                                    return <Mention pubkey={ref.PubKey!} />
                                }
                                case "e": {
                                    let eText = hexToBech32("note", ref.Event!).substring(0, 12);
                                    return <Link key={ref.Event} to={eventLink(ref.Event!)} onClick={(e) => e.stopPropagation()}>#{eText}</Link>;
                                }
                                case "t": {
                                    return <Hashtag tag={ref.Hashtag!} />
                                }
                            }
                        }
                        return <b style={{ color: "var(--error)" }}>{matchTag[0]}?</b>;
                    } else {
                        return match;
                    }
                });
            }
            return f;
        }).flat();
    }

    function extractInvoices(fragments: Fragment[]) {
        return fragments.map(f => {
            if (typeof f === "string") {
                return f.split(InvoiceRegex).map(i => {
                    if (i.toLowerCase().startsWith("lnbc")) {
                        return <Invoice key={i} invoice={i} />
                    } else {
                        return i;
                    }
                });
            }
            return f;
        }).flat();
    }

    function extractHashtags(fragments: Fragment[]) {
        return fragments.map(f => {
            if (typeof f === "string") {
                return f.split(HashtagRegex).map(i => {
                    if (i.toLowerCase().startsWith("#")) {
                        return <Hashtag tag={i.substring(1)} />
                    } else {
                        return i;
                    }
                });
            }
            return f;
        }).flat();
    }

    function transformLi(frag: TextFragment) {
        let fragments = transformText(frag)
        return <li>{fragments}</li>
    }

    function transformParagraph(frag: TextFragment) {
        const fragments = transformText(frag)
        if (fragments.every(f => typeof f === 'string')) {
            return <p>{fragments}</p>
        }
        return <>{fragments}</>
    }

    function transformText(frag: TextFragment) {
        if (frag.body === undefined) {
            debugger;
        }
        let fragments = extractMentions(frag);
        fragments = extractLinks(fragments);
        fragments = extractInvoices(fragments);
        fragments = extractHashtags(fragments);
        return fragments;
    }

    const components = useMemo(() => {
        return {
            p: (x: any) => transformParagraph({ body: x.children ?? [], tags, users }),
            a: (x: any) => <HyperText link={x.href} creator={creator} />,
            li: (x: any) => transformLi({ body: x.children ?? [], tags, users }),
        };
    }, [content]);

    const disableMarkdownLinks = useCallback(() => (tree: any) => {
        visit(tree, (node, index, parent) => {
            if (
                parent &&
                typeof index === 'number' &&
                (node.type === 'link' ||
                    node.type === 'linkReference' ||
                    node.type === 'image' ||
                    node.type === 'imageReference' ||
                    node.type === 'definition')
            ) {
                node.type = 'text';
                node.value = content.slice(node.position.start.offset, node.position.end.offset).replace(/\)$/, ' )');
                return SKIP;
            }
        })
    }, [content]);
    return <ReactMarkdown
        className="text"
        components={components}
        remarkPlugins={[disableMarkdownLinks]}
    >{content}</ReactMarkdown>
}