/**
 * SafeSimplifyMeshToLines.jsx
 * Converts mesh artwork into two editable linework PDFs:
 *   1. Mesh-derived geometry lines
 *   2. Contour-style interpretive lines
 * Separates exterior outlines and internal structure onto distinct layers.
 * Safe for large meshes in Illustrator.
 */

(function() {

    if (app.documents.length === 0) {
        alert("Please open a document first!");
        return;
    }

    var doc = app.activeDocument;
    var saveFolder;

    if (doc.saved) {
        saveFolder = doc.path;
    } else {
        saveFolder = Folder.selectDialog("Select folder to save PDFs:");
        if (!saveFolder) {
            alert("No folder selected. Exiting script.");
            return;
        }
    }

    // --- Utility Functions ---
    function getOrMakeLayer(name, parent) {
        parent = parent || doc;
        try { return parent.layers.getByName(name); }
        catch (e) { 
            var l = parent.layers.add(); 
            l.name = name; 
            return l; 
        }
    }

    function blackColor() {
        var c = new GrayColor();
        c.gray = 0;
        return c;
    }

    function deselectAll() {
        app.executeMenuCommand("deselectall");
    }

    function safeExpandAndOutline(item) {
        item.selected = true;
        try { app.executeMenuCommand('expandStyle'); } catch(e){}
        try { app.executeMenuCommand('expand'); } catch(e){}
        try { app.executeMenuCommand('outline'); } catch(e){}
        deselectAll();
    }

    function isLargeArea(path) {
        // Only PathItems and CompoundPathItems
        if (!path.filled || !("area" in path)) return false;
        return Math.abs(path.area || 0) > 1000;
    }

    // --- MESH-DERIVED LINE VERSION ---
    var meshGroup = getOrMakeLayer("Mesh-Line-Version");
    var meshOutlineLayer = meshGroup.layers.add();
    meshOutlineLayer.name = "Exterior Outlines";
    var meshInternalLayer = meshGroup.layers.add();
    meshInternalLayer.name = "Internal Structure";

    // Process each pageItem individually
    for (var i = doc.pageItems.length - 1; i >= 0; i--) {
        var item = doc.pageItems[i];

        // Duplicate into meshGroup
        var copy = item.duplicate(meshGroup, ElementPlacement.PLACEATBEGINNING);

        // Expand and outline safely
        safeExpandAndOutline(copy);

        // Style and move to outline or internal layer
        if (copy.typename === "PathItem" || copy.typename === "CompoundPathItem") {
            copy.strokeColor = blackColor();
            copy.filled = false;

            if (isLargeArea(copy)) {
                copy.move(meshOutlineLayer, ElementPlacement.PLACEATBEGINNING);
                copy.strokeWidth = 0.75;
            } else {
                copy.move(meshInternalLayer, ElementPlacement.PLACEATBEGINNING);
                copy.strokeWidth = 0.35;
                if ("opacity" in copy) copy.opacity = 60;
            }
        }
    }

    // Save first PDF
    var pdf1 = new File(saveFolder.fsName + "/Rock_Mesh_Lines.pdf");
    var pdfOptions = new PDFSaveOptions();
    pdfOptions.preserveEditability = true;
    doc.saveAs(pdf1, pdfOptions);

    // --- CONTOUR-STYLE INTERPRETIVE VERSION ---
    var contourGroup = getOrMakeLayer("Contour-Version");
    var contourOutlineLayer = contourGroup.layers.add();
    contourOutlineLayer.name = "Exterior Outlines";
    var contourInternalLayer = contourGroup.layers.add();
    contourInternalLayer.name = "Internal Structure";

    // Duplicate meshGroup items individually for contour version
    for (var j = meshGroup.pageItems.length - 1; j >= 0; j--) {
        var item = meshGroup.pageItems[j];
        var copy = item.duplicate(contourGroup, ElementPlacement.PLACEATBEGINNING);

        if ("strokeWidth" in copy && copy.strokeWidth > 0.5) {
            copy.move(contourOutlineLayer, ElementPlacement.PLACEATBEGINNING);
            copy.strokeWidth = 0.6;
        } else {
            copy.move(contourInternalLayer, ElementPlacement.PLACEATBEGINNING);
            copy.strokeWidth = 0.25;
            if ("opacity" in copy) copy.opacity = 50;
        }
    }

    // Save second PDF
    var pdf2 = new File(saveFolder.fsName + "/Rock_Contour_Lines.pdf");
    doc.saveAs(pdf2, pdfOptions);

    alert(
        "Conversion complete!\nSaved as:\n" +
        "- Rock_Mesh_Lines.pdf\n" +
        "- Rock_Contour_Lines.pdf\n\n" +
        "Layers separated for easy editing."
    );

})();