"use strict";

// Single source of truth for the osm2streets render layers.
//
// The same nine layers, in the same order, previously appeared four times:
// the merged-scene z_index table, the scene style JSON, the generated QGIS
// project (layer dict + draw_order), and the README's manual rebuild snippet.
// Adding a layer or changing a z-index meant editing all of them in lockstep,
// and a missed copy produces a silently mis-stacked scene downstream in
// Blender/Cesium. Everything now derives from SCENE_LAYERS.
//
// zIndex doubles as draw order: lowest paints first (bottom of the stack).
// outline: null means "no stroke" (QGIS gets a fully transparent outline).

const SCENE_LAYERS = [
  {
    id: "road_surface",
    splitKey: "roadSurface",
    zIndex: 10,
    title: "road surface",
    fill: "#2b2b28",
    outline: "#1e1e1c",
    outlineWidth: 0.04,
  },
  {
    id: "intersection_surface",
    splitKey: "intersectionSurface",
    zIndex: 20,
    title: "intersection surface",
    fill: "#2b2b28",
    outline: "#1e1e1c",
    outlineWidth: 0.04,
  },
  {
    id: "sidewalks",
    splitKey: "sidewalks",
    zIndex: 30,
    title: "sidewalks",
    fill: "#bebeb6",
    outline: "#9c9c94",
    outlineWidth: 0.025,
  },
  {
    id: "sidewalk_corners",
    splitKey: "sidewalkCorners",
    zIndex: 40,
    title: "sidewalk corners",
    fill: "#bebeb6",
    outline: "#9c9c94",
    outlineWidth: 0.025,
  },
  {
    id: "lane_separators",
    splitKey: "laneSeparators",
    zIndex: 50,
    title: "lane separators",
    fill: "#eeeee6",
    outline: null,
    outlineWidth: 0,
  },
  {
    id: "center_lines",
    splitKey: "centerLines",
    zIndex: 60,
    title: "center lines",
    fill: "#f5be2a",
    outline: null,
    outlineWidth: 0,
  },
  {
    id: "crosswalks",
    splitKey: "crosswalks",
    zIndex: 70,
    title: "crosswalks",
    fill: "#fffff6",
    outline: null,
    outlineWidth: 0,
  },
  {
    id: "vehicle_stop_lines",
    splitKey: "vehicleStopLines",
    zIndex: 80,
    title: "vehicle stop lines",
    fill: "#fffff6",
    outline: null,
    outlineWidth: 0,
  },
  {
    id: "lane_arrows_webscale",
    splitKey: "laneArrows",
    zIndex: 90,
    title: "lane arrows",
    fill: "#fffff6",
    outline: "#2b2b28",
    outlineAlpha: 200,
    outlineWidth: 0.015,
  },
];

const SCENE_FILE = "osm2streets_scene.geojson";
const SCENE_STYLE_FILE = "osm2streets_scene_style.json";

function layerFile(layer) {
  return `${layer.id}.geojson`;
}

// getCollection(layer) -> FeatureCollection, so callers can source layers from
// the in-memory split (build) or from disk (reimport) with the same merge.
function mergeScene(getCollection) {
  return {
    type: "FeatureCollection",
    features: SCENE_LAYERS.flatMap((layer) => {
      const collection = getCollection(layer) || {};
      return (collection.features || []).map((feature) => ({
        ...feature,
        properties: {
          ...(feature.properties || {}),
          render_layer: layer.id,
          z_index: layer.zIndex,
        },
      }));
    }),
  };
}

function sceneStyle() {
  return {
    version: 1,
    geometry: "polygon",
    sortProperty: "z_index",
    layerProperty: "render_layer",
    layers: SCENE_LAYERS.map((layer) => ({
      id: layer.id,
      zIndex: layer.zIndex,
      fill: layer.fill,
      outline: layer.outline,
      outlineWidth: layer.outlineWidth,
    })),
  };
}

// QGIS symbol properties want "r,g,b,a" strings rather than hex.
function qgisRgba(hex, alpha = 255) {
  if (!hex) return "0,0,0,0";
  const match = /^#?([0-9a-f]{6})$/i.exec(hex.trim());
  if (!match) {
    throw new Error(`Expected #rrggbb color, got: ${hex}`);
  }
  const value = parseInt(match[1], 16);
  const r = (value >> 16) & 0xff;
  const g = (value >> 8) & 0xff;
  const b = value & 0xff;
  return `${r},${g},${b},${alpha}`;
}

module.exports = {
  SCENE_LAYERS,
  SCENE_FILE,
  SCENE_STYLE_FILE,
  layerFile,
  mergeScene,
  sceneStyle,
  qgisRgba,
};