trading-platform/apps/backend/src/modules/investment/services/account.service.ts

/**
 * Investment Account Service
 * Manages user investment accounts
 */

import { v4 as uuidv4 } from 'uuid';
import { productService, InvestmentProduct } from './product.service';

// ============================================================================
// Types
// ============================================================================

export type AccountStatus = 'active' | 'suspended' | 'closed';

export interface InvestmentAccount {
  id: string;
  userId: string;
  productId: string;
  product?: InvestmentProduct;
  status: AccountStatus;
  balance: number;
  initialInvestment: number;
  totalDeposited: number;
  totalWithdrawn: number;
  totalEarnings: number;
  totalFeesPaid: number;
  unrealizedPnl: number;
  unrealizedPnlPercent: number;
  openedAt: Date;
  closedAt: Date | null;
  updatedAt: Date;
}

export interface CreateAccountInput {
  userId: string;
  productId: string;
  initialDeposit: number;
}

export interface AccountSummary {
  totalBalance: number;
  totalEarnings: number;
  totalDeposited: number;
  totalWithdrawn: number;
  overallReturn: number;
  overallReturnPercent: number;
  accounts: InvestmentAccount[];
}

// ============================================================================
// In-Memory Storage
// ============================================================================

const accounts: Map<string, InvestmentAccount> = new Map();

// ============================================================================
// Account Service
// ============================================================================

class AccountService {
  /**
   * Get all accounts for a user
   */
  async getUserAccounts(userId: string): Promise<InvestmentAccount[]> {
    const userAccounts = Array.from(accounts.values()).filter((a) => a.userId === userId);

    // Attach product info
    for (const account of userAccounts) {
      account.product = (await productService.getProductById(account.productId)) || undefined;
    }

    return userAccounts;
  }

  /**
   * Get account by ID
   */
  async getAccountById(accountId: string): Promise<InvestmentAccount | null> {
    const account = accounts.get(accountId);
    if (!account) return null;

    account.product = (await productService.getProductById(account.productId)) || undefined;
    return account;
  }

  /**
   * Get account by user and product
   */
  async getAccountByUserAndProduct(
    userId: string,
    productId: string
  ): Promise<InvestmentAccount | null> {
    const account = Array.from(accounts.values()).find(
      (a) => a.userId === userId && a.productId === productId && a.status !== 'closed'
    );

    if (!account) return null;

    account.product = (await productService.getProductById(account.productId)) || undefined;
    return account;
  }

  /**
   * Create a new investment account
   */
  async createAccount(input: CreateAccountInput): Promise<InvestmentAccount> {
    // Validate product exists
    const product = await productService.getProductById(input.productId);
    if (!product) {
      throw new Error(`Product not found: ${input.productId}`);
    }

    // Check minimum investment
    if (input.initialDeposit < product.minInvestment) {
      throw new Error(
        `Minimum investment for ${product.name} is $${product.minInvestment}`
      );
    }

    // Check if user already has an account with this product
    const existingAccount = await this.getAccountByUserAndProduct(
      input.userId,
      input.productId
    );
    if (existingAccount) {
      throw new Error(`User already has an account with ${product.name}`);
    }

    const account: InvestmentAccount = {
      id: uuidv4(),
      userId: input.userId,
      productId: input.productId,
      product,
      status: 'active',
      balance: input.initialDeposit,
      initialInvestment: input.initialDeposit,
      totalDeposited: input.initialDeposit,
      totalWithdrawn: 0,
      totalEarnings: 0,
      totalFeesPaid: 0,
      unrealizedPnl: 0,
      unrealizedPnlPercent: 0,
      openedAt: new Date(),
      closedAt: null,
      updatedAt: new Date(),
    };

    accounts.set(account.id, account);
    return account;
  }

  /**
   * Deposit funds to an account
   */
  async deposit(accountId: string, amount: number): Promise<InvestmentAccount> {
    const account = accounts.get(accountId);
    if (!account) {
      throw new Error(`Account not found: ${accountId}`);
    }

    if (account.status !== 'active') {
      throw new Error(`Cannot deposit to ${account.status} account`);
    }

    if (amount <= 0) {
      throw new Error('Deposit amount must be positive');
    }

    account.balance += amount;
    account.totalDeposited += amount;
    account.updatedAt = new Date();

    return account;
  }

  /**
   * Record earnings for an account
   */
  async recordEarnings(
    accountId: string,
    grossEarnings: number,
    performanceFee: number
  ): Promise<InvestmentAccount> {
    const account = accounts.get(accountId);
    if (!account) {
      throw new Error(`Account not found: ${accountId}`);
    }

    const netEarnings = grossEarnings - performanceFee;

    account.balance += netEarnings;
    account.totalEarnings += netEarnings;
    account.totalFeesPaid += performanceFee;
    account.updatedAt = new Date();

    return account;
  }

  /**
   * Update unrealized P&L
   */
  async updateUnrealizedPnl(
    accountId: string,
    unrealizedPnl: number
  ): Promise<InvestmentAccount> {
    const account = accounts.get(accountId);
    if (!account) {
      throw new Error(`Account not found: ${accountId}`);
    }

    account.unrealizedPnl = unrealizedPnl;
    account.unrealizedPnlPercent =
      account.totalDeposited > 0
        ? (unrealizedPnl / account.totalDeposited) * 100
        : 0;
    account.updatedAt = new Date();

    return account;
  }

  /**
   * Close an account
   */
  async closeAccount(accountId: string): Promise<InvestmentAccount> {
    const account = accounts.get(accountId);
    if (!account) {
      throw new Error(`Account not found: ${accountId}`);
    }

    if (account.status === 'closed') {
      throw new Error('Account is already closed');
    }

    account.status = 'closed';
    account.closedAt = new Date();
    account.updatedAt = new Date();

    return account;
  }

  /**
   * Suspend an account
   */
  async suspendAccount(accountId: string): Promise<InvestmentAccount> {
    const account = accounts.get(accountId);
    if (!account) {
      throw new Error(`Account not found: ${accountId}`);
    }

    account.status = 'suspended';
    account.updatedAt = new Date();

    return account;
  }

  /**
   * Reactivate a suspended account
   */
  async reactivateAccount(accountId: string): Promise<InvestmentAccount> {
    const account = accounts.get(accountId);
    if (!account) {
      throw new Error(`Account not found: ${accountId}`);
    }

    if (account.status !== 'suspended') {
      throw new Error('Only suspended accounts can be reactivated');
    }

    account.status = 'active';
    account.updatedAt = new Date();

    return account;
  }

  /**
   * Get account summary for a user
   */
  async getAccountSummary(userId: string): Promise<AccountSummary> {
    const userAccounts = await this.getUserAccounts(userId);

    const summary: AccountSummary = {
      totalBalance: 0,
      totalEarnings: 0,
      totalDeposited: 0,
      totalWithdrawn: 0,
      overallReturn: 0,
      overallReturnPercent: 0,
      accounts: userAccounts,
    };

    for (const account of userAccounts) {
      if (account.status !== 'closed') {
        summary.totalBalance += account.balance;
        summary.totalEarnings += account.totalEarnings;
        summary.totalDeposited += account.totalDeposited;
        summary.totalWithdrawn += account.totalWithdrawn;
      }
    }

    summary.overallReturn = summary.totalBalance - summary.totalDeposited + summary.totalWithdrawn;
    summary.overallReturnPercent =
      summary.totalDeposited > 0
        ? (summary.overallReturn / summary.totalDeposited) * 100
        : 0;

    return summary;
  }

  /**
   * Get account performance history
   */
  async getAccountPerformance(
    accountId: string,
    days: number = 30
  ): Promise<{ date: string; balance: number; pnl: number }[]> {
    const account = accounts.get(accountId);
    if (!account) {
      throw new Error(`Account not found: ${accountId}`);
    }

    // Generate mock performance data
    const performance: { date: string; balance: number; pnl: number }[] = [];
    let balance = account.initialInvestment;

    for (let i = days; i >= 0; i--) {
      const date = new Date();
      date.setDate(date.getDate() - i);

      const dailyChange = balance * ((Math.random() - 0.3) * 0.02);
      balance += dailyChange;

      performance.push({
        date: date.toISOString().split('T')[0],
        balance,
        pnl: balance - account.initialInvestment,
      });
    }

    return performance;
  }
}

// Export singleton instance
export const accountService = new AccountService();