import { Config, ImportOptions, Thing } from "@types";
import { adapters } from "../adapters";
import { DummyOpenHAB, OpenHAB } from "../openhab";


const createFilter = (filter?: string) => {
  if(!filter) {
    return (_: Thing) => true;
  }
  
  return new Function("$", `const v = ${filter}; if(typeof v !== 'boolean') throw new Error("Filter should be of boolean type"); return v;`) as ((_: Thing) => true);
};

export const importThings = async (config: Config, options: ImportOptions) => {  
  const OH = options.dryRun ? DummyOpenHAB : OpenHAB;
  const openhab = new OH(config.openHAB);

  const sources = options.sources ?? Object.keys(config.sources);

  const things = (await Promise.all(sources.map(source => {
    const { type, config: cfg } = config.sources[source];
    
    const constructor = adapters[type as keyof (typeof adapters)];

    if (!constructor) {
      throw new Error(`Unknown source type '${type}'`);
    }

    return new constructor(source, cfg).loadThings();
  }))).flat();

  const existingThings = await openhab.getThings();
  const existingThingsUIDs = existingThings.map(t => t.UID);  

  const filter = createFilter(options.where);
  
  const thingsToImport = things
    .filter(t => !existingThingsUIDs.includes(t.UID))
    .filter(filter);

  if (options.force) {
    await openhab.deleteThings(...thingsToImport.map(t => t.UID));
  }

  await openhab.createThings(...thingsToImport);

  return thingsToImport;
}