import { BadRequestException, Injectable } from "@nestjs/common";
import { PrismaService } from "../prisma/prisma.service";
import { PlaidService } from "../plaid/plaid.service";
import { TellerService } from "../teller/teller.service";
import { OpaqueIdService } from "../common/opaque-id.service";
import { PlanLimitsService } from "../stripe/plan-limits.service";
import { UpdateAccountOwnershipDto } from "./dto/update-account-ownership.dto";

const UI_PAGE_SIZE_LIMIT = 25;

@Injectable()
export class AccountsService {
  constructor(
    private readonly prisma: PrismaService,
    private readonly plaidService: PlaidService,
    private readonly tellerService: TellerService,
    private readonly opaqueIds: OpaqueIdService,
    private readonly planLimits: PlanLimitsService,
  ) {}

  async list(userId: string, page = 1, limit = 20) {
    const requestedLimit = Number.isFinite(limit) && limit ? limit : 20;
    const take = Math.min(Math.max(requestedLimit, 1), UI_PAGE_SIZE_LIMIT);
    const skip = (page - 1) * take;
    const [accounts, total] = await Promise.all([
      this.prisma.account.findMany({
        where: { userId, isActive: true },
        orderBy: { createdAt: "desc" },
        skip,
        take,
        select: {
          id: true,
          institutionName: true,
          accountType: true,
          mask: true,
          currentBalance: true,
          availableBalance: true,
          isoCurrencyCode: true,
          lastBalanceSync: true,
          lastTransactionSync: true,
          lastSyncAttemptAt: true,
          syncStatus: true,
          lastSyncError: true,
          syncConsecutiveFailures: true,
          plaidWebhookCode: true,
          plaidWebhookAt: true,
          tellerAccountId: true,
          householdId: true,
          ownerUserId: true,
          ownershipType: true,
          isActive: true,
          createdAt: true,
          // Intentionally omit plaidAccessToken — never expose the encrypted token
        },
      }),
      this.prisma.account.count({ where: { userId, isActive: true } }),
    ]);
    return {
      accounts: accounts.map((account) => ({
        id: this.opaqueIds.encode("account", userId, account.id),
        institutionName: account.institutionName,
        accountType: account.accountType,
        mask: account.mask,
        currentBalance: account.currentBalance,
        availableBalance: account.availableBalance,
        isoCurrencyCode: account.isoCurrencyCode,
        lastBalanceSync: account.lastBalanceSync,
        lastTransactionSync: account.lastTransactionSync,
        lastSyncAttemptAt: account.lastSyncAttemptAt,
        syncStatus: account.syncStatus,
        lastSyncError: account.lastSyncError,
        syncConsecutiveFailures: account.syncConsecutiveFailures,
        plaidWebhookCode: account.plaidWebhookCode,
        plaidWebhookAt: account.plaidWebhookAt,
        tellerConnected: Boolean(account.tellerAccountId),
        householdId: account.householdId,
        ownerUserId: account.ownerUserId,
        ownershipType: account.ownershipType,
        isActive: account.isActive,
        createdAt: account.createdAt,
      })),
      total,
      page,
      limit: take,
    };
  }

  async createLinkToken(userId: string) {
    await this.planLimits.assertCanAddAccounts(userId, 1);
    return this.plaidService.createLinkToken(userId);
  }

  async refreshBalances(userId: string) {
    const [plaid, teller] = await Promise.all([
      this.plaidService.syncBalancesForUser(userId),
      this.tellerService.syncBalancesForUser(userId),
    ]);
    return { updated: plaid.updated + teller.updated, plaid, teller };
  }

  async createManualAccount(
    userId: string,
    payload: { institutionName: string; accountType: string; mask?: string },
  ) {
    await this.planLimits.assertCanAddAccounts(userId, 1);
    const account = await this.prisma.account.create({
      data: {
        userId,
        institutionName: payload.institutionName,
        accountType: payload.accountType,
        mask: payload.mask ?? null,
        ownerUserId: userId,
        ownershipType: "mine",
        isActive: true,
      },
      select: {
        id: true,
        institutionName: true,
        accountType: true,
        mask: true,
        ownerUserId: true,
        ownershipType: true,
        isActive: true,
        createdAt: true,
      },
    });
    return {
      ...account,
      id: this.opaqueIds.encode("account", userId, account.id),
    };
  }

  async updateOwnership(userId: string, accountHandle: string, payload: UpdateAccountOwnershipDto) {
    const accountId = this.opaqueIds.decode("account", userId, accountHandle);
    const account = await this.prisma.account.findFirst({
      where: { id: accountId, userId, isActive: true },
    });
    if (!account) throw new BadRequestException("Account not found.");

    let householdId: string | null = null;
    let ownerUserId: string | null = userId;

    if (payload.ownershipType === "mine") {
      householdId = null;
      ownerUserId = userId;
    } else {
      if (!payload.householdId) {
        throw new BadRequestException("Household is required for shared account ownership.");
      }
      const requesterMembership = await this.prisma.householdMember.findFirst({
        where: { householdId: payload.householdId, userId, status: "active" },
      });
      if (!requesterMembership) throw new BadRequestException("Household not found.");
      householdId = payload.householdId;

      if (payload.ownershipType === "joint") {
        ownerUserId = null;
      } else {
        if (!payload.ownerUserId || payload.ownerUserId === userId) {
          throw new BadRequestException("Owner user must be another active household member for 'theirs' accounts.");
        }
        const ownerMembership = await this.prisma.householdMember.findFirst({
          where: { householdId, userId: payload.ownerUserId, status: "active" },
        });
        if (!ownerMembership) throw new BadRequestException("Owner must be an active household member.");
        ownerUserId = payload.ownerUserId;
      }
    }

    const updated = await this.prisma.account.update({
      where: { id: accountId },
      data: {
        ownershipType: payload.ownershipType,
        householdId,
        ownerUserId,
      },
      select: {
        id: true,
        institutionName: true,
        accountType: true,
        mask: true,
        householdId: true,
        ownerUserId: true,
        ownershipType: true,
        isActive: true,
        createdAt: true,
      },
    });

    await this.prisma.auditLog.create({
      data: {
        userId,
        action: "account.ownership.update",
        metadata: {
          accountId,
          householdId,
          ownerUserId,
          ownershipType: payload.ownershipType,
        },
      },
    });

    return {
      ...updated,
      id: this.opaqueIds.encode("account", userId, updated.id),
    };
  }
}