import type { Location, ShipModel } from "@deadhead/content";
import { buildContract, standardCargo, type SimContent } from "./board";
import type { Contract } from "./contract";
import { createRng, deriveSeed, type Seed } from "./rng";

/** The tutorial loaner is the company's Courier. */
export function loanerModel(content: SimContent): ShipModel {
  const courier = content.shipModels.find((s) => s.archetype === "courier");
  if (!courier) throw new Error("Content has no Courier ship model");
  return courier;
}

export type TutorialLocationId = "earth" | "moon";

export interface TutorialBoardInput {
  /** Where the loaner currently is; contracts start here (decision 0.5.3). */
  loanerLocationId: TutorialLocationId;
  periodIndex: number;
  worldSeed: Seed;
}

function location(id: string, content: SimContent): Location {
  const found = content.locations.find((l) => l.id === id);
  if (!found) throw new Error(`Unknown location ${id}`);
  return found;
}

/**
 * The tutorial "company board": Earth↔Moon only, Standard cargo sized to fit
 * the loaner, starting at the loaner's location. Each payout is the tutorial
 * share of the equivalent normal payout, rounded to whole credits.
 */
export function generateTutorialBoard(input: TutorialBoardInput, content: SimContent): Contract[] {
  const { loanerLocationId, periodIndex, worldSeed } = input;
  const { config } = content;
  const origin = location(loanerLocationId, content);
  const destination = location(loanerLocationId === "earth" ? "moon" : "earth", content);
  const cargoType = standardCargo(content);
  const maxMass = Math.min(config.contractMassTonnes.max, loanerModel(content).cargoCapacityTonnes);
  const rng = createRng(deriveSeed(worldSeed, `tutorial:${loanerLocationId}:${periodIndex}`));

  return Array.from({ length: config.tutorialBoardSize }, (_, i) => {
    const contract = buildContract(
      {
        id: `tutorial:${loanerLocationId}:${periodIndex}:${i}`,
        origin,
        destination,
        cargoType,
        tier: 0,
        massTonnes: rng.int(config.contractMassTonnes.min, maxMass),
        firstContact: false,
        periodIndex,
      },
      content,
    );
    return { ...contract, payout: Math.round(contract.payout * config.tutorialPayoutShare) };
  });
}