// Copyright (C) 2026 Danilo M. <danix@danix.xyz>
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License version 2 as
// published by the Free Software Foundation.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.

.pragma library

// Splits a message into prose and fenced code, so each code block can carry
// its own copy button: Qt's markdown renders fences but gives no per-block
// hook. A fence opens with ``` or ~~~ (three or more) after any indent, as
// inside a list item, and closes with a run of the same character at least
// as long. The fence's indent is stripped from its lines. A fence still open
// at the end, which is normal while a reply streams, is a code segment with
// open set.
function split(text) {
    const out = [];
    const prose = [];
    let code = null;
    const flush = () => {
        const t = prose.join("\n").trim();
        if (t) out.push({ kind: "prose", text: t });
        prose.length = 0;
    };
    for (const line of text.split("\n")) {
        if (code) {
            const close = /^\s*(`{3,}|~{3,})\s*$/.exec(line);
            if (close && close[1][0] === code.fence[0] && close[1].length >= code.fence.length) {
                out.push({ kind: "code", lang: code.lang, text: code.lines.join("\n"), open: false });
                code = null;
            } else {
                code.lines.push(line.startsWith(code.indent) ? line.slice(code.indent.length)
                                                             : line.trimStart());
            }
            continue;
        }
        const open = /^(\s*)(`{3,}|~{3,})\s*([^`\s]*)/.exec(line);
        if (open) {
            flush();
            code = { indent: open[1], fence: open[2], lang: open[3], lines: [] };
        } else {
            prose.push(line);
        }
    }
    if (code) out.push({ kind: "code", lang: code.lang, text: code.lines.join("\n"), open: true });
    else flush();
    return out;
}