import { GameRuntimeStats, GameState } from '../types';

function clampNonNegativeInteger(value: unknown) {
  if (typeof value !== 'number' || !Number.isFinite(value)) return 0;
  return Math.max(0, Math.floor(value));
}

function getIsoTimestamp(now: number) {
  return new Date(now).toISOString();
}

export function createInitialGameRuntimeStats(
  options: {
    isActiveRun?: boolean;
    now?: number;
  } = {},
): GameRuntimeStats {
  const now = options.now ?? Date.now();

  return {
    playTimeMs: 0,
    lastPlayTickAt: options.isActiveRun ? getIsoTimestamp(now) : null,
    hostileNpcsDefeated: 0,
    questsAccepted: 0,
    itemsUsed: 0,
    scenesTraveled: 0,
  };
}

export function normalizeGameRuntimeStats(
  stats: Partial<GameRuntimeStats> | null | undefined,
  options: {
    isActiveRun?: boolean;
    now?: number;
  } = {},
): GameRuntimeStats {
  const now = options.now ?? Date.now();

  return {
    playTimeMs: typeof stats?.playTimeMs === 'number' && Number.isFinite(stats.playTimeMs)
      ? Math.max(0, stats.playTimeMs)
      : 0,
    lastPlayTickAt: options.isActiveRun ? getIsoTimestamp(now) : null,
    hostileNpcsDefeated: clampNonNegativeInteger(stats?.hostileNpcsDefeated),
    questsAccepted: clampNonNegativeInteger(stats?.questsAccepted),
    itemsUsed: clampNonNegativeInteger(stats?.itemsUsed),
    scenesTraveled: clampNonNegativeInteger(stats?.scenesTraveled),
  };
}

export function incrementGameRuntimeStats(
  stats: GameRuntimeStats,
  increments: Partial<Pick<GameRuntimeStats, 'hostileNpcsDefeated' | 'questsAccepted' | 'itemsUsed' | 'scenesTraveled'>>,
): GameRuntimeStats {
  return {
    ...stats,
    hostileNpcsDefeated: stats.hostileNpcsDefeated + clampNonNegativeInteger(increments.hostileNpcsDefeated),
    questsAccepted: stats.questsAccepted + clampNonNegativeInteger(increments.questsAccepted),
    itemsUsed: stats.itemsUsed + clampNonNegativeInteger(increments.itemsUsed),
    scenesTraveled: stats.scenesTraveled + clampNonNegativeInteger(increments.scenesTraveled),
  };
}

export function syncGameRuntimePlayTime(stats: GameRuntimeStats, now = Date.now()): GameRuntimeStats {
  if (!stats.lastPlayTickAt) {
    return {
      ...stats,
      lastPlayTickAt: getIsoTimestamp(now),
    };
  }

  const lastTickMs = Date.parse(stats.lastPlayTickAt);
  if (Number.isNaN(lastTickMs)) {
    return {
      ...stats,
      lastPlayTickAt: getIsoTimestamp(now),
    };
  }

  return {
    ...stats,
    playTimeMs: stats.playTimeMs + Math.max(0, now - lastTickMs),
    lastPlayTickAt: getIsoTimestamp(now),
  };
}

export function getLiveGamePlayTimeMs(stats: GameRuntimeStats, now = Date.now()) {
  if (!stats.lastPlayTickAt) return stats.playTimeMs;

  const lastTickMs = Date.parse(stats.lastPlayTickAt);
  if (Number.isNaN(lastTickMs)) return stats.playTimeMs;

  return stats.playTimeMs + Math.max(0, now - lastTickMs);
}

export function syncGameStatePlayTime(state: GameState, now = Date.now()): GameState {
  return {
    ...state,
    runtimeStats: syncGameRuntimePlayTime(state.runtimeStats, now),
  };
}