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

/** The tutorial loaner: the content's company ship (decision 0.5.29). */
export function loanerModel(content: SimContent): ShipModel {
  const id = content.config.tutorialLoanerShipModelId;
  const loaner = content.shipModels.find((s) => s.id === id);
  if (!loaner) throw new Error(`Content has no loaner ship model "${id}"`);
  return loaner;
}

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

export interface TutorialBoardInput {
  /** Where the loaner currently is; contracts start here (decision 0.5.3). */
  loanerLocationId: TutorialLocationId;
  /** Tutorial runs already flown; the board is for run `runsCompleted + 1`. */
  runsCompleted: number;
  periodIndex: number;
}

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" (CR-001, Step 10A.3): three Standard contracts
 * from the loaner's location to the other end of the Earth–Moon route, at the
 * light, medium and full mass tiers, each paying the tutorial share. A scripted
 * contract for the upcoming run (decision 0.5.33) replaces the medium slot.
 * The board is fully determined by its inputs.
 */
export function generateTutorialBoard(input: TutorialBoardInput, content: SimContent): Contract[] {
  const { loanerLocationId, runsCompleted, periodIndex } = input;
  const { config } = content;
  const origin = location(loanerLocationId, content);
  const destination = location(loanerLocationId === "earth" ? "moon" : "earth", content);
  const tiers = config.tutorialMassTonnes;
  const run = runsCompleted + 1;
  const scripted = content.scriptedTutorialContracts.find((s) => s.run === run);

  const slot = (i: number, massTonnes: number): Contract => {
    const special = i === 1 ? scripted : undefined;
    const cargoType = special
      ? content.cargoTypes.find((c) => c.id === special.cargoTypeId)
      : standardCargo(content);
    if (!cargoType) throw new Error(`Unknown cargo ${special?.cargoTypeId}`);
    const contract = buildContract(
      {
        id: `tutorial:${loanerLocationId}:${run}:${periodIndex}:${i}`,
        origin,
        destination,
        cargoType,
        tier: 0,
        massTonnes,
        firstContact: false,
        periodIndex,
      },
      content,
    );
    const share = contract.payout * config.tutorialPayoutShare * (special?.payMultiplier ?? 1);
    return {
      ...contract,
      payout: Math.round(share),
      ...(special ? { scriptedId: special.id } : {}),
    };
  };

  return [slot(0, tiers.light), slot(1, tiers.medium), slot(2, tiers.full)];
}