import type {Bot,PopulationPlan,State,WorldTrigger} from './types';

function scoreCandidate(bot:Bot,state:State,zone:string){
 const home=state.homes.find(h=>h.id===bot.homeId);
 let score=0;
 if(bot.zone===zone)score+=60;
 if(home?.zone===zone)score+=50;
 if(bot.routine.preferredZones.includes(zone))score+=35;
 score+=Math.round(bot.personality.sociability*0.15);
 score+=Math.round(bot.personality.curiosity*0.1);
 if(bot.simulationBand==='background')score+=10;
 if(bot.simulationBand==='dormant')score+=5;
 if(bot.status==='offline')score+=4;
 if(bot.tier==='hero')score+=2;
 return score;
}

export function runPopulationDirector(state:State,trigger:WorldTrigger):PopulationPlan{
 const living=state.bots.filter(b=>b.status!=='dead'&&b.status!=='retired');
 const active=state.bots.filter(b=>b.status==='online');
 const activeInZone=active.filter(b=>b.zone===trigger.zone);
 const foreground=state.bots.filter(b=>b.simulationBand==='foreground'&&b.status!=='dead'&&b.status!=='retired');
 const background=state.bots.filter(b=>b.simulationBand==='background'&&b.status!=='dead'&&b.status!=='retired');
 const settings=state.settings.population;
 const target=Math.min(settings.defaultZoneTarget,settings.zoneMax);
 const requested=Math.max(0,target-activeInZone.length);
 const capacity=Math.max(0,Math.min(
  settings.zoneMax-activeInZone.length,
  settings.serverMax-active.length,
  settings.foregroundMax-foreground.length,
  settings.backgroundMax-background.length+requested
 ));

 const rejectedReasons:string[]=[];
 if(requested===0)rejectedReasons.push('Zone already meets its living population target.');
 if(capacity===0&&requested>0)rejectedReasons.push('Population request blocked by zone, server, or simulation capacity.');

 const candidates=living
  .filter(b=>b.zone!==trigger.zone||b.status!=='online')
  .filter(b=>b.simulationBand!=='foreground')
  .map(bot=>({bot,score:scoreCandidate(bot,state,trigger.zone)}))
  .filter(x=>x.score>=20)
  .sort((a,b)=>b.score-a.score||a.bot.name.localeCompare(b.bot.name));

 const count=Math.min(requested,capacity,candidates.length);
 const selectedBotIds=candidates.slice(0,count).map(x=>x.bot.id);
 if(requested>0&&selectedBotIds.length<Math.min(requested,capacity))rejectedReasons.push('Not enough believable existing residents were available; no synthetic identities were injected.');

 return {
  id:crypto.randomUUID(),
  trigger,
  target,
  activeBefore:activeInZone.length,
  requested,
  capacity,
  selectedBotIds,
  rejectedReasons,
  createdAt:new Date().toISOString()
 };
}

export function applySimulationPopulationPlan(state:State,plan:PopulationPlan){
 for(const id of plan.selectedBotIds){
  const bot=state.bots.find(b=>b.id===id);
  if(!bot||bot.status==='dead'||bot.status==='retired')continue;
  bot.status='online';
  bot.zone=plan.trigger.zone;
  bot.simulationBand='foreground';
  bot.goal=`Spend time in ${plan.trigger.zone} for a believable personal reason while continuing my own life.`;
 }
 for(const bot of state.bots){
  if(bot.status==='dead'||bot.status==='retired'||plan.selectedBotIds.includes(bot.id))continue;
  if(bot.zone===plan.trigger.zone&&bot.status==='online')bot.simulationBand='foreground';
  else if(bot.status==='online')bot.simulationBand='background';
 }
}

export function chooseHomeForNewResident(state:State,bot:Bot){
 const candidates=state.homes
  .filter(h=>h.type!=='homeless'&&h.residentIds.length<h.capacity)
  .map(home=>({home,score:(home.zone===state.director.zone?40:0)+(home.zone===bot.zone?60:0)+home.safety}))
  .sort((a,b)=>b.score-a.score);
 return candidates[0]?.home;
}