/**
 * FinancialService — central ledger for all in-game money operations.
 *
 * Money sources of truth:
 *   Player's club  → squad.finances.budget  (overall balance)
 *   AI clubs       → squad.finances.budget  (their available funds)
 *
 * All monetary mutations go through this module. Never write budget
 * directly from route handlers or domain functions.
 */

import { saveService, SaveService } from "@/backend/SaveService";
import type { SaveMeta } from "@/backend/SaveService";
import type { Squad, RosterPlayer } from "@/types/playerTypes";
import { Player } from "@/Domain/Player";

// ── Constants ─────────────────────────────────────────────────────────────────

export const TICKET_PRICE = 25;
export const HOME_FILL_RATE = 0.65;

// ── Internal helpers ──────────────────────────────────────────────────────────

function estimateWeeklyWage(p: RosterPlayer): number {
  const rating = Player.overallAvg(p);
  return Math.round(Math.pow(rating, 2.2) * 50);
}

// ── Balance getters ───────────────────────────────────────────────────────────

/** Club budget from squad.finances. Works for both player and AI clubs. */
export function getClubBudget(squad: Squad): number {
  return squad.finances?.budget ?? 0;
}

// ── Pure financial calculations (no side effects) ─────────────────────────────

/**
 * Net weekly P/L for a squad:
 *   commercial_income / 52  −  total_weekly_salaries  −  operational (10% of salaries)
 */
export function calcWeeklyDelta(squad: Squad): number {
  const weeklyCommercial = Math.round((squad.finances?.commercial ?? 0) / 52);
  const weeklyPlayerSalary = squad.players.reduce((sum, p) => sum + estimateWeeklyWage(p), 0);
  const weeklyOperational = Math.round(weeklyPlayerSalary * 0.1);
  return weeklyCommercial - weeklyPlayerSalary - weeklyOperational;
}

/** Home matchday ticket revenue based on stadium capacity. */
export function calcMatchdayRevenue(squad: Squad): number {
  const capacity = squad.venue?.capacity ?? 0;
  return capacity > 0 ? Math.round(capacity * HOME_FILL_RATE * TICKET_PRICE) : 0;
}

// ── Season start ──────────────────────────────────────────────────────────────

/**
 * Credit the full season broadcasting fee to the player's club budget.
 * Called once when a new save is created.
 */
export async function applyBroadcasting(
  saveId: string,
  meta: SaveMeta,
  leagueSlug: string,
  clubSlug: string,
): Promise<SaveMeta> {
  const squad = await saveService.getSquad(saveId, leagueSlug, clubSlug);
  const broadcasting = squad?.finances?.broadcasting ?? 0;
  if (broadcasting <= 0 || !squad?.finances) return meta;

  await saveService.saveSquad(saveId, leagueSlug, clubSlug, {
    ...squad,
    finances: {
      ...squad.finances,
      budget: (squad.finances.budget ?? 0) + broadcasting,
    },
  });

  return meta;
}

// ── Transfer fee exchange ─────────────────────────────────────────────────────

type ClubRef = {
  squad: Squad;
  leagueSlug: string;
  clubSlug: string;
  isPlayerClub: boolean;
};

/**
 * Move a transfer fee from the buyer to the seller and persist all changes.
 *
 * Both player and AI clubs use squad.finances.budget as their unified money pool.
 *
 * Returns the updated SaveMeta.
 */
export async function executeTransferFee(
  saveId: string,
  meta: SaveMeta,
  buyer: ClubRef,
  seller: ClubRef,
  fee: number,
  service: SaveService = saveService,
): Promise<SaveMeta> {
  const squadSaves: Promise<void>[] = [];

  // ── Debit buyer ────────────────────────────────────────────────────────────
  if (buyer.squad.finances) {
    const currentBudget = buyer.squad.finances.budget ?? 0;
    squadSaves.push(
      service.saveSquad(saveId, buyer.leagueSlug, buyer.clubSlug, {
        ...buyer.squad,
        finances: { ...buyer.squad.finances, budget: Math.max(0, currentBudget - fee) },
      }),
    );
  }

  // ── Credit seller ──────────────────────────────────────────────────────────
  if (seller.squad.finances) {
    const currentBudget = seller.squad.finances.budget ?? 0;
    squadSaves.push(
      service.saveSquad(saveId, seller.leagueSlug, seller.clubSlug, {
        ...seller.squad,
        finances: {
          ...seller.squad.finances,
          budget: currentBudget + fee,
        },
      }),
    );
  }

  await Promise.all(squadSaves);
  return meta;
}