import { transformText } from "./formatter";

function stripUnsupportedMarkdown(text: string): string {
    return text
        .replace(/!\[[^\]]*\]\([^)]+\)/g, "")
        .replace(/\[([^\]]+)\]\(([^)]+)\)/g, "$1 ($2)")
        .replace(/~~(.+?)~~/g, "$1")
        .replace(/`(.+?)`/g, "$1");
}

function applyInlineMarkdown(text: string): string {
    return text.replace(
        /\*\*\*(.+?)\*\*\*|\*\*(.+?)\*\*|_(.+?)_/g,
        (_match: string, boldItalic: string | undefined, bold: string | undefined, italic: string | undefined) => {
            if (boldItalic !== undefined) return transformText(boldItalic, "bold-italic");
            if (bold !== undefined) return transformText(bold, "bold");
            return transformText(italic!, "italic");
        }
    );
}

export function markdownToLinkedIn(text: string): string {
    const processed = stripUnsupportedMarkdown(text);
    const lines = processed.split("\n");
    const output: string[] = [];
    let pendingBlanks = 0;
    let skipNextBlanks = false;
    let inListContext = false;

    for (const line of lines) {
        if (line.trim() === "") {
            if (!skipNextBlanks) pendingBlanks++;
            continue;
        }

        skipNextBlanks = false;

        if (line.startsWith("# ")) {
            for (let i = 0; i < pendingBlanks; i++) output.push("");
            pendingBlanks = 0;
            inListContext = false;
            const headingText = line.slice(2).toUpperCase();
            output.push(transformText(applyInlineMarkdown(headingText), "bold") + "  ");
            skipNextBlanks = true;
            continue;
        }

        if (line.startsWith("## ")) {
            for (let i = 0; i < pendingBlanks; i++) output.push("");
            pendingBlanks = 0;
            inListContext = false;
            const headingText = line.slice(3);
            output.push(transformText(applyInlineMarkdown(headingText), "bold") + "  ");
            skipNextBlanks = true;
            continue;
        }

        const hMatch = line.match(/^#{3,6}\s/);
        if (hMatch) {
            for (let i = 0; i < pendingBlanks; i++) output.push("");
            pendingBlanks = 0;
            inListContext = false;
            const headingText = line.slice(hMatch[0].length);
            output.push(transformText(applyInlineMarkdown(headingText), "bold") + "  ");
            skipNextBlanks = true;
            continue;
        }

        if (line.startsWith("> ")) {
            for (let i = 0; i < pendingBlanks; i++) output.push("");
            pendingBlanks = 0;
            inListContext = false;
            output.push(transformText(applyInlineMarkdown(line.slice(2)), "italic"));
            continue;
        }

        if (line.startsWith("- ") || line.startsWith("* ")) {
            if (!inListContext) {
                for (let i = 0; i < pendingBlanks; i++) output.push("");
            }
            pendingBlanks = 0;
            output.push("— " + applyInlineMarkdown(line.slice(2)) + "  ");
            inListContext = true;
            continue;
        }

        const orderedMatch = line.match(/^(\d+)[.)]\s+(.+)/);
        if (orderedMatch) {
            if (!inListContext) {
                for (let i = 0; i < pendingBlanks; i++) output.push("");
            }
            pendingBlanks = 0;
            const num = orderedMatch[1]!;
            const content = orderedMatch[2]!;
            output.push(`${num}/ ${applyInlineMarkdown(content)}  `);
            inListContext = true;
            continue;
        }

        if (/^-{3,}$/.test(line.trim()) || /^\*{3,}$/.test(line.trim())) {
            for (let i = 0; i < pendingBlanks; i++) output.push("");
            pendingBlanks = 0;
            inListContext = false;
            output.push("");
            continue;
        }

        for (let i = 0; i < pendingBlanks; i++) output.push("");
        pendingBlanks = 0;
        inListContext = false;
        output.push(applyInlineMarkdown(line));
    }

    return output.join("\n").replace(/[ \u00A0]\./g, ".").trimEnd();
}