import {OcctKernel} from 'occt-wasm';
import wasmUrl from 'occt-wasm/dist/occt-wasm.wasm?url';
import {prepareSlotReview} from '../../slot-review/index.mjs';
import {planClearanceSlots} from '../../slot-review/clearance-plan.mjs';
import type {SlotWorkMessage,SlotWorkResponse} from './slot-wire';

let consumed=false;
self.onmessage=async(event:MessageEvent<SlotWorkMessage>)=>{
  if(consumed)return;consumed=true;
  let kernel:OcctKernel|undefined,response:SlotWorkResponse|undefined;
  const message=event.data;
  if(typeof message?.id!=='string'||!/^[-0-9a-f]{36}$/.test(message.id))return;
  try{
    if(message.version!=='browser-slot-work-0.1'||!(message.bytes instanceof ArrayBuffer)||message.bytes.byteLength<1||message.bytes.byteLength>20*1024*1024||!['prepare','plan'].includes(message.kind)||Object.keys(message).sort().join(',')!=='bytes,id,kind,request,version')throw new Error('Invalid work envelope');
    const owned=structuredClone(message);
    kernel=await OcctKernel.init({wasm:wasmUrl});
    response=owned.kind==='prepare'
      ?{version:'browser-slot-result-0.1',id:owned.id,kind:'prepare',result:await prepareSlotReview(kernel,owned.bytes,owned.request)}
      :{version:'browser-slot-result-0.1',id:owned.id,kind:'plan',result:await planClearanceSlots(kernel,owned.bytes,owned.request)};
    if(response.result.diagnostic==='cleanup_failed')throw new Error('Cleanup incomplete');
  }catch{response={version:'browser-slot-error-0.1',id:message.id};}
  finally{try{kernel?.[Symbol.dispose]();}catch{response={version:'browser-slot-error-0.1',id:message.id};}}
  // The owned kernel is gone before the consumer receives any candidate.
  self.postMessage(response);
};