// Research: labs (bought with funds) produce research points slowly over time;
// points buy nodes of a small tree. Research survives a legacy restart.

export function labCost(state, ctx) {
  const r = ctx.rules.research;
  return Math.ceil(r.labBaseCost * r.labCostGrowth ** state.labs);
}

export function rpPerSecond(state, ctx, mods) {
  return state.labs * ctx.rules.research.rpPerLabPerSecond * mods.rp;
}

export function buyLab(state, ctx) {
  const { labMax } = ctx.rules.research;
  const cost = labCost(state, ctx);
  if (state.labs >= labMax || state.funds < cost) return false;
  state.funds -= cost;
  state.labs += 1;
  return true;
}

/** 'owned' | 'available' | 'locked' */
export function researchStatus(state, node) {
  if (state.research.includes(node.id)) return 'owned';
  return node.requires.every((id) => state.research.includes(id)) ? 'available' : 'locked';
}

export function buyResearch(state, ctx, id) {
  const node = ctx.researchById.get(id);
  if (!node || researchStatus(state, node) !== 'available' || state.rp < node.cost) return false;
  state.rp -= node.cost;
  state.research.push(id);
  return true;
}

export function stepResearch(state, ctx, dt, mods) {
  state.rp += rpPerSecond(state, ctx, mods) * dt;
}