// Markdown -> HTML subset (Qt rich text) renderer. Pure ES5, no deps.
// IMPORTANT (QML): functions are TOP-LEVEL so a QML namespace import exposes
// them directly:  import "../components/Markdown.js" as Markdown
//                  ... Markdown.render(src) ...
// (an IIFE + var would hide them under Markdown.Markdown and QML would throw
// "Property 'render' of object [object Object] is not a function").
// The module.exports guard at the bottom is for node tests only.
//
// render(src, baseUrl, opts):
//   baseUrl - resolves relative links/images against (the note's WebDAV folder)
//   opts.imageMap  - { url: localCachePath } -> inline <img> instead of placeholder
//   opts.imageLabel - localized word for the image placeholder ("image")

function escapeHtml(s) {
    return s.replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;");
}

function resolveUrl(u, baseUrl) {
    if (baseUrl && !/^[a-z]+:/i.test(u) && u.charAt(0) !== "#" && u.charAt(0) !== "/") {
        return String(baseUrl).replace(/\/+$/, "") + "/" + u;
    }
    return u;
}

function inline(s, baseUrl, opts) {
    s = escapeHtml(s);
    s = s.replace(/`([^`]+)`/g, "<tt>$1</tt>");
    s = s.replace(/!\[([^\]]*)\]\(([^)\s]+)\)/g, function (m, alt, u) {
        var key = resolveUrl(u, baseUrl);
        var p = opts && opts.imageMap ? opts.imageMap[key] : "";
        if (p && p !== "error") {
            return '<img src="file://' + p + '" width="350" height="-1" alt="' + alt + '"/>';
        }
        var label = opts && opts.imageLabel ? opts.imageLabel : "image";
        return "<i>[" + label + ": " + alt + "]</i>";
    });
    s = s.replace(/\[([^\]]+)\]\(([^)\s]+)\)/g, function (m, t, u) {
        return '<a href="' + resolveUrl(u, baseUrl) + '">' + t + "</a>";
    });
    // Wiki links [[Nota]] -> quill://<url-encoded name.md>; the app intercepts
    // the scheme and opens the note in the editor.
    s = s.replace(/\[\[([^\]]+)\]\]/g, function (m, name) {
        var full = name;
        var lower = name.toLowerCase();
        if (lower.indexOf(".md") !== lower.length - 3) full = name + ".md";
        var label = full;
        if (label.toLowerCase().indexOf(".md") === label.length - 3) {
            label = label.substring(0, label.length - 3);
        }
        return '<a href="quill://' + encodeURIComponent(full) + '">' + label + "</a>";
    });
    s = s.replace(/\*\*(.+?)\*\*/g, "<b>$1</b>");
    s = s.replace(/(^|[^*])\*([^*\n]+)\*(?!\*)/g, "$1<i>$2</i>");
    s = s.replace(/~~([^~]+)~~/g, "<s>$1</s>");
    return s;
}

// Split a table row on unescaped pipes; leading/trailing pipe is optional.
function splitRow(s) {
    var t = s.trim();
    if (t.charAt(0) === "|") t = t.substring(1);
    if (t.charAt(t.length - 1) === "|") t = t.substring(0, t.length - 1);
    var parts = t.split("|");
    var cells = [];
    for (var i = 0; i < parts.length; i++) cells.push(parts[i].trim());
    return cells;
}

// GFM alignment from a delimiter cell: ":---" left, "---:" right, ":---:" center.
function alignmentFromSep(sep, n) {
    var parts = splitRow(sep);
    var aligns = [];
    for (var i = 0; i < n; i++) {
        var p = i < parts.length ? parts[i] : "";
        if (p.charAt(0) === ":" && p.charAt(p.length - 1) === ":") aligns.push("center");
        else if (p.charAt(0) === ":") aligns.push("left");
        else if (p.charAt(p.length - 1) === ":") aligns.push("right");
        else aligns.push("");
    }
    return aligns;
}

function alignAttr(a) {
    return a ? ' align="' + a + '"' : "";
}

function render(src, baseUrl, opts) {
    if (!src) return "";
    src = src.replace(/\r\n/g, "\n").replace(/\r/g, "\n");
    // Strip UTF-8 BOM: a leading \uFEFF breaks the first heading/block
    // regex (line no longer starts with #) and the symbol stays visible.
    src = src.replace(/^\uFEFF/, "");
    var lines = src.split("\n");
    var out = [];
    var i = 0;
    var n = lines.length;

    var headingRe = /^\s*(#{1,6})\s+(.*)$/;
    var hrRe = /^\s*(-{3,}|\*{3,}|_{3,})\s*$/;
    var quoteRe = /^>\s?(.*)$/;
    var listRe = /^\s*([-*+]|\d+[.)])\s+(.*)$/;
    var fenceRe = /^```/;
    var tableHeaderRe = /^\s*\|.*\|/;
    var tableSepRe = /^\s*\|?[\s:|-]+\|?\s*$/;

    while (i < n) {
        var line = lines[i];
        var m;

        if (fenceRe.test(line)) {
            var buf = [];
            i++;
            while (i < n && !fenceRe.test(lines[i])) {
                buf.push(lines[i]);
                i++;
            }
            i++; // closing fence
            out.push('<pre style="color:#9a9a9a">' + escapeHtml(buf.join("\n")) + "</pre>");
            continue;
        }

        // GFM table: header row + delimiter row (must contain a pipe and a dash).
        if (tableHeaderRe.test(line) && i + 1 < n) {
            var sepLine = lines[i + 1];
            if (tableSepRe.test(sepLine) && sepLine.indexOf("|") >= 0 && sepLine.indexOf("-") >= 0) {
                var headerCells = splitRow(line);
                var aligns = alignmentFromSep(sepLine, headerCells.length);
                var tbody = [];
                i += 2;
                while (i < n) {
                    var dl = lines[i];
                    if (dl.trim() === "" || dl.indexOf("|") < 0) break;
                    tbody.push(splitRow(dl));
                    i++;
                }
                var t = '<table border="1" cellspacing="0" cellpadding="4">';
                t += "<tr>";
                for (var h = 0; h < headerCells.length; h++) {
                    t += "<th" + alignAttr(aligns[h]) + "><b>" + inline(headerCells[h], baseUrl, opts) + "</b></th>";
                }
                t += "</tr>";
                for (var r = 0; r < tbody.length; r++) {
                    t += "<tr>";
                    var row = tbody[r];
                    for (var c = 0; c < headerCells.length; c++) {
                        var cell = c < row.length ? row[c] : "";
                        t += "<td" + alignAttr(aligns[c]) + ">" + inline(cell, baseUrl, opts) + "</td>";
                    }
                    t += "</tr>";
                }
                t += "</table>";
                out.push(t);
                continue;
            }
        }

        m = headingRe.exec(line);
        if (m) {
            var level = m[1].length;
            out.push("<h" + level + ">" + inline(m[2], baseUrl, opts) + "</h" + level + ">");
            i++;
            continue;
        }

        if (hrRe.test(line)) {
            out.push("<hr/>");
            i++;
            continue;
        }

        m = quoteRe.exec(line);
        if (m) {
            var q = [];
            while (i < n) {
                var qm = quoteRe.exec(lines[i]);
                if (!qm) break;
                q.push(inline(qm[1], baseUrl, opts));
                i++;
            }
            out.push('<p style="color:#8f8f8f"><i>' + q.join("<br/>") + "</i></p>");
            continue;
        }

        m = listRe.exec(line);
        if (m) {
            var ordered = /^\s*\d/.test(line);
            var items = [];
            while (i < n) {
                var lm = listRe.exec(lines[i]);
                if (!lm) break;
                items.push("<li>" + inline(lm[2], baseUrl, opts) + "</li>");
                i++;
            }
            out.push(ordered ? "<ol>" + items.join("") + "</ol>" : "<ul>" + items.join("") + "</ul>");
            continue;
        }

        if (line.trim() === "") {
            i++;
            continue;
        }

        var para = [];
        while (i < n) {
            var pl = lines[i];
            if (pl.trim() === "" || headingRe.test(pl) || hrRe.test(pl) ||
                quoteRe.test(pl) || listRe.test(pl) || fenceRe.test(pl)) {
                break;
            }
            para.push(inline(pl, baseUrl, opts));
            i++;
        }
        out.push("<p>" + para.join("<br/>") + "</p>");
    }
    return out.join("\n");
}

if (typeof module !== "undefined" && module.exports) {
    module.exports = { render: render };
}