import {
  firstPursuitScoutSourceBattleId,
  firstPursuitScoutVisitId
} from '../data/firstPursuitScoutMemory';
import {
  firstPursuitScoutVisitDefinition,
  getFirstPursuitScoutVisitChoice,
  type FirstPursuitScoutVisitChoice
} from '../data/firstPursuitScoutVisit';
import {
  applyCampVisitReward,
  getCampaignState,
  setCampaignState,
  type CampaignState
} from './campaignState';

type FirstPursuitScoutActionFailure =
  | 'invalid-campaign'
  | 'invalid-choice'
  | 'already-completed'
  | 'save-unavailable';

export type FirstPursuitScoutActionResult =
  | {
      ok: true;
      choice: FirstPursuitScoutVisitChoice;
      campaign: CampaignState;
    }
  | {
      ok: false;
      reason: FirstPursuitScoutActionFailure;
    };

export function completeFirstPursuitScoutVisit(
  choiceId: string
): FirstPursuitScoutActionResult {
  let campaign: CampaignState;
  try {
    campaign = getCampaignState();
  } catch {
    return { ok: false, reason: 'save-unavailable' };
  }
  const settlement = campaign.battleHistory[firstPursuitScoutSourceBattleId];
  const report = campaign.firstBattleReport;
  if (
    campaign.step !== 'first-camp' ||
    campaign.latestBattleId !== firstPursuitScoutSourceBattleId ||
    settlement?.outcome !== 'victory' ||
    report?.battleId !== firstPursuitScoutSourceBattleId ||
    report.outcome !== 'victory'
  ) {
    return { ok: false, reason: 'invalid-campaign' };
  }

  const choice = getFirstPursuitScoutVisitChoice(choiceId);
  if (!choice) {
    return { ok: false, reason: 'invalid-choice' };
  }
  if (campaign.completedCampVisits.includes(firstPursuitScoutVisitId)) {
    return { ok: false, reason: 'already-completed' };
  }

  let updated: CampaignState | undefined;
  try {
    updated = applyCampVisitReward(
      firstPursuitScoutVisitId,
      {
        bondId: firstPursuitScoutVisitDefinition.bondId,
        bondExp: choice.bondExp,
        itemRewards: [...choice.itemRewards]
      },
      choice.id
    );
  } catch {
    try {
      setCampaignState(campaign);
    } catch {
      // setCampaignState restores the in-memory snapshot before persistence.
    }
    return { ok: false, reason: 'save-unavailable' };
  }
  if (!updated) {
    return { ok: false, reason: 'save-unavailable' };
  }

  return {
    ok: true,
    choice,
    campaign: updated
  };
}