import stylegen from "@maplibre/maplibre-gl-inspect/lib/stylegen";
import colors from "@maplibre/maplibre-gl-inspect/lib/colors";
import type {FilterSpecification,LayerSpecification } from "maplibre-gl";

export type HighlightedLayer = LayerSpecification & {filter?: FilterSpecification};

function changeLayer(l: HighlightedLayer, layer: LayerSpecification) {
  if(l.type === "circle") {
    l.paint!["circle-radius"] = 3;
  } else if(l.type === "line") {
    l.paint!["line-width"] = 2;
  }

  if("filter" in layer) {
    l.filter = layer.filter;
  } else {
    delete l["filter"];
  }
  l.id = l.id + "_highlight";
  return l;
}

export function colorHighlightedLayer(layer?: LayerSpecification): HighlightedLayer | null {
  if(!layer || layer.type === "background" || layer.type === "raster") return null;

  const sourceLayerId = layer["source-layer"] || "";
  const color = colors.brightColor(sourceLayerId, 1);

  if(layer.type === "fill" || layer.type === "fill-extrusion") {
    return changeLayer(stylegen.polygonLayer(color, color, layer.source, layer["source-layer"]), layer);
  }

  if(layer.type === "symbol" || layer.type === "circle") {
    return changeLayer(stylegen.circleLayer(color, layer.source, layer["source-layer"]), layer);
  }

  if(layer.type === "line") {
    return changeLayer(stylegen.lineLayer(color, layer.source, layer["source-layer"]), layer);
  }

  return null;
}