import { CRS, TileLayer, type WMSOptions, type WMSParams } from 'leaflet';
import { bool, str, type PropDef } from '../core/props.ts';
import { tileLayerProps, urlProp } from '../core/shared-props.ts';
import {
  WithProps,
  type LeafletAddEventListener,
  type LeafletRemoveEventListener,
} from '../core/with-props.ts';
import type { TileLayerEvents } from '../core/event-types.ts';

// WMS request parameters have no individual setters -- they're merged into the
// query string through setParams().
function param<T>(key: keyof WMSParams): (obj: TileLayer.WMS, value: T) => void {
  return (obj, value) => {
    obj.setParams({ [key]: value } as unknown as WMSParams);
  };
}

// `crs` takes a CRS instance, not a primitive, so it's looked up by name from
// Leaflet's built-in set rather than decoded like a plain value. Constructor-
// only, like the rest of tileLayerProps -- Leaflet has no setter for it.
const NAMED_CRS = {
  EPSG3857: CRS.EPSG3857,
  EPSG4326: CRS.EPSG4326,
  EPSG3395: CRS.EPSG3395,
  Simple: CRS.Simple,
};
type CrsName = keyof typeof NAMED_CRS;

const crsProp: PropDef<CRS> = {
  default: CRS.EPSG3857,
  decode: (raw) => NAMED_CRS[raw as CrsName] ?? CRS.EPSG3857,
  encode: (value) =>
    value === CRS.EPSG3857
      ? null
      : ((Object.keys(NAMED_CRS) as CrsName[]).find((name) => NAMED_CRS[name] === value) ?? null),
};

export class LeafletTileLayerWMS extends WithProps({
  url: urlProp,
  ...tileLayerProps,
  layers: str('', { set: param('layers') }),
  styles: str('', { set: param('styles') }),
  format: str('image/jpeg', { set: param('format') }),
  transparent: bool(false, { set: param('transparent') }),
  version: str('1.1.1', { set: param('version') }),
  uppercase: bool(),
  crs: crsProp,
}) {
  declare readonly leafletObject?: TileLayer.WMS;
  declare addEventListener: LeafletAddEventListener<TileLayerEvents>;
  declare removeEventListener: LeafletRemoveEventListener<TileLayerEvents>;

  createLeafletObject(options: WMSOptions): TileLayer.WMS {
    return new TileLayer.WMS(this.url, options);
  }
}

customElements.define('leaflet-tile-layer-wms', LeafletTileLayerWMS);