/**
 * Persistent chip pool shared by the poker and blackjack tables.
 *
 * The pool lives on Profiles at progression.chipBank (plus
 * progression.chipBankRefilledAt for the daily top-up cooldown). Chips enter
 * the pool only by playing the non-card minigames (1 XP = CHIP_PER_XP chips);
 * the card games are pure sinks: buy-ins deduct from the pool and settled
 * bankrolls credit back, so the pool never creates or destroys chips itself.
 *
 * Server-only module (imports the realtime bus). The pure helpers at the top
 * are safe to unit-test without a database.
 */

import type { Payload } from "payload";
import { broadcastToUser } from "@/lib/realtime/bus";

/** Chips earned per XP point in the non-card minigames. */
export const CHIP_PER_XP = 10;

/** Chips a daily top-up adds when the pool runs dry. */
export const CHIP_TOP_UP_AMOUNT = 500;

/** The top-up is claimable while the pool is below this many chips. */
export const CHIP_TOP_UP_THRESHOLD = 500;

/** One top-up claim per day. */
export const CHIP_TOP_UP_COOLDOWN_MS = 24 * 60 * 60_000;

/** Chips earned for a run that granted xpGained XP (never negative). */
export function chipsForXp(xpGained: number): number {
  if (!Number.isFinite(xpGained) || xpGained <= 0) return 0;
  return Math.round(xpGained * CHIP_PER_XP);
}

export interface ChipBankState {
  chipBank: number;
  topUpAvailable: boolean;
  /** ISO timestamp of when the next top-up unlocks; null when claimable now. */
  nextTopUpAt: string | null;
}

/** Pure eligibility + countdown math for the daily top-up. */
export function chipTopUpState(
  chipBank: number,
  refilledAt: string | null | undefined,
  now: number = Date.now(),
): ChipBankState {
  if (refilledAt) {
    const refilled = Date.parse(refilledAt);
    if (Number.isFinite(refilled)) {
      const elapsed = now - refilled;
      if (elapsed < CHIP_TOP_UP_COOLDOWN_MS) {
        return {
          chipBank,
          topUpAvailable: false,
          nextTopUpAt: new Date(refilled + CHIP_TOP_UP_COOLDOWN_MS).toISOString(),
        };
      }
    }
  }
  return { chipBank, topUpAvailable: chipBank < CHIP_TOP_UP_THRESHOLD, nextTopUpAt: null };
}

interface ProfileProgression {
  xp?: unknown;
  chipBank?: number | null;
  chipBankRefilledAt?: string | Date | null;
}

/** Payload may hand date fields back as Date objects; normalize to ISO strings. */
function isoOrNull(value: string | Date | null | undefined): string | null {
  if (!value) return null;
  if (value instanceof Date) return Number.isNaN(value.getTime()) ? null : value.toISOString();
  return value;
}

/**
 * Resolve a user's chip bank state; null when the user has no profile
 * (untracked users such as integration-test placeholders play without
 * pool accounting).
 */
export async function readChipBankState(
  payload: Payload,
  userId: number,
): Promise<ChipBankState | null> {
  const profile = await findProfile(payload, userId);
  if (!profile) return null;
  const progression = (profile.progression ?? {}) as ProfileProgression;
  return chipTopUpState(progression.chipBank ?? 0, isoOrNull(progression.chipBankRefilledAt));
}

export interface ChipBuyInResult {
  /** false when the user has no profile (no pool accounting applies). */
  settled: boolean;
  chipBank: number | null;
}

/**
 * Deduct a table buy-in from the user's pool. Throws (with both chip totals
 * in the message) when the pool cannot cover it; call sites wrap the error
 * with the player's display name.
 */
export async function spendChipBuyIn(
  payload: Payload,
  userId: number,
  amount: number,
): Promise<ChipBuyInResult> {
  const profile = await findProfile(payload, userId);
  if (!profile) return { settled: false, chipBank: null };
  const progression = (profile.progression ?? {}) as ProfileProgression;
  const current = progression.chipBank ?? 0;
  if (current < amount) {
    throw new Error(
      `Not enough chips: ${current} of ${amount} needed. Play the other minigames to earn more chips.`,
    );
  }
  return writeChipBank(payload, profile, userId, current - amount);
}

/**
 * Credit settled chips back to the pool (fire-and-forget style: callers may
 * void this; failures are logged and skipped so one broken profile cannot
 * block a table teardown).
 */
export async function creditChips(payload: Payload, userId: number, amount: number): Promise<void> {
  if (!Number.isFinite(amount) || amount <= 0) return;
  const profile = await findProfile(payload, userId);
  if (!profile) return;
  const progression = (profile.progression ?? {}) as ProfileProgression;
  const current = progression.chipBank ?? 0;
  await writeChipBank(payload, profile, userId, current + amount);
}

/**
 * Claim the daily top-up: tops the pool up to CHIP_TOP_UP_AMOUNT while the
 * balance is under the threshold, at most once per cooldown window. Throws
 * with a user-facing message when not eligible.
 */
export async function claimChipTopUpForUser(
  payload: Payload,
  userId: number,
): Promise<ChipBankState> {
  const profile = await findProfile(payload, userId);
  if (!profile) throw new Error("No profile found for this user.");
  const progression = (profile.progression ?? {}) as ProfileProgression;
  const state = chipTopUpState(
    progression.chipBank ?? 0,
    isoOrNull(progression.chipBankRefilledAt),
  );
  if (!state.topUpAvailable) {
    throw new Error("Your chip top-up is not available yet. Come back later.");
  }
  const next = Math.max(state.chipBank, CHIP_TOP_UP_AMOUNT);
  await writeChipBank(payload, profile, userId, next, new Date().toISOString());
  return chipTopUpState(next, new Date().toISOString());
}

async function findProfile(payload: Payload, userId: number) {
  const profileRes = await payload.find({
    collection: "profiles",
    where: { user: { equals: userId } },
    limit: 1,
    depth: 0,
    overrideAccess: true,
  });
  return profileRes.docs[0] ?? null;
}

/**
 * Persist a new chip bank value (stripping the virtual xp key, mirroring the
 * minigame action convention), then push the new absolute balance to the
 * user's SSE channel so open card tables and dashboards stay in sync.
 */
async function writeChipBank(
  payload: Payload,
  profile: { id: number | string; progression?: unknown },
  userId: number,
  chipBank: number,
  refilledAt?: string,
): Promise<ChipBuyInResult> {
  const progression = (profile.progression ?? {}) as ProfileProgression;
  const { xp: _xp, ...progressionRest } = progression;
  const data: Record<string, unknown> = {
    ...progressionRest,
    chipBank: Math.max(0, chipBank),
  };
  if (refilledAt) data.chipBankRefilledAt = refilledAt;

  await payload.update({
    collection: "profiles",
    id: profile.id,
    data: { progression: data },
    overrideAccess: true,
    depth: 0,
  });
  broadcastToUser("profile-update", userId, {
    reason: "chips",
    chipBank: data.chipBank,
    profileId: profile.id,
  });
  return { settled: true, chipBank: data.chipBank as number };
}