import { Injectable, Logger } from "@nestjs/common";
import { ConfigService } from "@nestjs/config";
import { InjectRepository } from "@nestjs/typeorm";
import { Repository } from "typeorm";

import { ExternalProfile } from "../companies/entities/external-profile.entity";
import { EmailClientService } from "../notifications/email-client.service";
import { SmsClientService } from "../notifications/sms-client.service";
import { ResetChannel } from "./dto/forgot-password.dto";
import {
  ForgotPasswordService,
  RESET_LINK_TTL_MS,
  type ResetTicket,
} from "./forgot-password.service";
import { maskOtpTarget } from "./mask-target.util";
import { isDomesticPhone, type OtpTarget } from "../otp/otp.service";

/** The account a staff-triggered reset would land on. */
export interface CustomerResetTarget {
  userId: string;
  name: string;
  email: string | null;
  phone: string | null;
  /**
   * Whether the SMS gateway (domestic-only) can reach `phone`. `null` when
   * there is no phone. The backoffice uses this to disable the SMS channel for
   * foreign numbers instead of sending a link that will never arrive.
   */
  phoneIsDomestic: boolean | null;
}

export interface SentResetLink {
  channel: ResetChannel;
  maskedTarget: string;
  expiresAt: string;
}

@Injectable()
export class CustomerResetService {
  private readonly logger = new Logger(CustomerResetService.name);

  constructor(
    @InjectRepository(ExternalProfile)
    private readonly externalProfileRepository: Repository<ExternalProfile>,
    private readonly forgotPasswordService: ForgotPasswordService,
    private readonly emailClient: EmailClientService,
    private readonly smsClient: SmsClientService,
    private readonly config: ConfigService,
  ) {}

  /**
   * The IAM account a reset would actually reach. The backoffice shows these
   * values rather than `company.email` / `company.phone`: the company row holds
   * business contact detail, while the link is delivered to the primary
   * contact's own login credentials — the two drift apart routinely, and showing
   * the wrong one has staff telling customers to check an inbox nothing was sent
   * to.
   */
  async getResetTarget(companyId: string): Promise<CustomerResetTarget | null> {
    const resolved = await this.resolvePrimaryContactUser(companyId);
    if (!resolved) return null;

    const { profile, user, userId } = resolved;
    return {
      userId,
      name: `${profile.firstName} ${profile.lastName}`.trim(),
      email: user.email ?? null,
      phone: user.phoneNumber ?? null,
      phoneIsDomestic: user.phoneNumber
        ? isDomesticPhone(user.phoneNumber)
        : null,
    };
  }

  /**
   * Mint a password-reset link and send it to the company's primary contact.
   * Returns the masked destination, or null when there is no eligible account
   * for that channel.
   *
   * Unlike the public flow this reports failure honestly — the caller is an
   * authenticated staff member, so there is nothing to enumerate.
   */
  async sendResetLinkToCustomer(
    companyId: string,
    channel: ResetChannel,
  ): Promise<SentResetLink | null> {
    const resolved = await this.resolvePrimaryContactUser(companyId);
    if (!resolved) return null;

    return this.sendResetLinkToUser(resolved.userId, channel, {
      scope: `company ${companyId}`,
    });
  }

  /**
   * Mint and deliver a reset link to a specific IAM account.
   *
   * The delivery half of {@link sendResetLinkToCustomer}, split out so callers
   * that resolve their target differently can reuse it: a customer is found via
   * the company's primary contact, while a shipping line has no contact row at
   * all and resolves straight off its own record. Everything below the lookup —
   * active-account gating, the domestic-SMS rule, mint-before-send, the
   * undelivered-link diagnostic — is identical for both and must stay that way.
   *
   * `scope` only labels the log line with whatever the caller resolved from.
   *
   * `allowWithoutCredential` relaxes the lookup for first-time activation:
   * the default gate requires an existing active credential (so a reset cannot
   * revive a suspended account), but an account that has never set a password
   * has no credential row yet and would be excluded from its own activation
   * link. Callers pass it only when the account is expected to be
   * password-less — see ShippingLineCompaniesService.
   */
  async sendResetLinkToUser(
    userId: string,
    channel: ResetChannel,
    options?: { scope?: string; allowWithoutCredential?: boolean },
  ): Promise<SentResetLink | null> {
    const sent = await this.sendResetLinkToUserOnChannels(userId, [channel], options);
    return sent[0] ?? null;
  }

  /**
   * One ticket, several channels. Minting retires every earlier ticket for the
   * user (`mintResetTicket`), so sending email and SMS as two separate mints
   * makes the first link dead on arrival — the same link must go to both.
   * Returns one entry per channel that was actually sent (unreachable channels
   * are skipped, not errors).
   */
  async sendResetLinkToUserOnChannels(
    userId: string,
    channels: ResetChannel[],
    options?: { scope?: string; allowWithoutCredential?: boolean },
  ): Promise<SentResetLink[]> {
    const user = options?.allowWithoutCredential
      ? await this.forgotPasswordService.resolveActivatableUserById(userId)
      : await this.forgotPasswordService.resolveActiveUserById(userId);

    if (!user?.id) {
      this.logger.warn(
        `User ${userId} is not an active account${
          options?.allowWithoutCredential
            ? ""
            : " (or has no active credential — pass allowWithoutCredential for first-time activation)"
        }`,
      );
      return [];
    }

    // Mint once, before any send: a failed send leaves an unused ticket that
    // simply expires, whereas sending a link before the ticket exists would
    // hand the customer a URL that is dead on arrival.
    let ticket: ResetTicket | null = null;
    const sent: SentResetLink[] = [];
    for (const channel of channels) {
      const target = this.forgotPasswordService.targetFor(user, channel);
      if (!target) continue;
      // The gateway silently drops foreign numbers — treat like a missing phone
      // rather than reporting "link sent" for a message that will never arrive.
      // The backoffice disables the channel up front via `phoneIsDomestic`; this
      // guards direct API calls.
      if (channel === "phone" && target.phone && !isDomesticPhone(target.phone)) {
        this.logger.warn(
          `Staff reset via SMS refused for user ${userId} — non-domestic phone`,
        );
        continue;
      }
      ticket ??= await this.forgotPasswordService.mintResetTicket(
        user.id,
        RESET_LINK_TTL_MS,
      );
      const result = await this.deliverResetLink(
        target,
        user.id,
        channel,
        ticket,
        options?.scope,
      );
      if (result) sent.push(result);
    }
    return sent;
  }

  /**
   * Shared tail: send the already-minted ticket to a resolved target → report.
   */
  private async deliverResetLink(
    target: OtpTarget,
    userId: string,
    channel: ResetChannel,
    ticket: ResetTicket,
    scope?: string,
  ): Promise<SentResetLink | null> {

    // A foreign number is unreachable by the domestic-only SMS gateway — treat
    // it like a missing phone rather than reporting "link sent" for a message
    const link = this.buildResetLink(ticket.userId, ticket.verificationCode);
    const expiresAt = new Date(Date.now() + RESET_LINK_TTL_MS);

    const { queued } = target.email
      ? await this.emailClient.sendEmail({
          to: target.email,
          subject: "Reset your EDR Freight password",
          text:
            "A password reset was started for your EDR Freight account.\n\n" +
            `Open this link to choose a new password:\n${link}\n\n` +
            "The link expires in 24 hours and can only be used once. If you did " +
            "not expect this, ignore this message — your password stays unchanged.",
        })
      : await this.smsClient.sendSms({
          to: target.phone as string,
          message: `Reset your EDR Freight password: ${link} (expires in 24 hours, single use)`,
        });

    this.logger.log(
      `Staff-triggered shipping line ${channel} reset link sent to user ${userId}${
        scope ? ` (${scope})` : ""
      } queued=${queued}`,
    );

    // SECURITY: logs a live password-reset credential in cleartext. Anyone with
    // read access to the log stream can set the password for the account named
    // on the same line — including on sends that succeeded, not just failures.
    // Kept deliberately: log aggregation is the debugging path for flaky
    // email/SMS here, the same tradeoff otp.service.ts makes for OTP codes. If
    // that is ever revisited, gate this on an env flag rather than deleting it,
    // so dev keeps its workflow.
    this.logger.warn(
      `reset-link.cleartext channel=${channel} user=${userId}${
        scope ? ` (${scope})` : ""
      } link=${link}`,
    );

    if (!queued) {
      // The ticket is committed and the backoffice is about to say "link sent",
      // but nothing left this process — with RABBITMQ_ENABLED=false both clients
      // are no-ops. Without this line the only symptom is a customer who never
      // receives anything, indistinguishable from carrier loss.
      this.logger.error(
        `reset-link.dispatch.dropped channel=${channel} user=${userId} rabbitmqEnabled=${
          process.env.RABBITMQ_ENABLED ?? "unset"
        } — transport reported no hand-off; no link will arrive`,
      );
      // SECURITY: logs a live password-reset credential in cleartext. Same
      // deliberate tradeoff the OTP service makes — this is the only way to
      // complete a reset on an environment with no broker. Only reached when
      // delivery already failed.
      this.logger.warn(`Undelivered reset link for user ${userId}: ${link}`);
    }

    return {
      channel,
      maskedTarget: maskOtpTarget(target),
      expiresAt: expiresAt.toISOString(),
    };
  }

  /**
   * The company's primary contact, gated on the same active-account rule the
   * public flow uses — so a suspended customer cannot be reactivated by a
   * staff-triggered reset (IAM's `set-password` flips `isActive` back on).
   */
  private async resolvePrimaryContactUser(companyId: string) {
    const profile = await this.externalProfileRepository.findOne({
      where: { companyId, isPrimaryContact: true },
    });

    if (!profile) {
      this.logger.warn(`Company ${companyId} has no primary contact profile`);
      return null;
    }

    const user = await this.forgotPasswordService.resolveActiveUserById(
      profile.userId,
    );
    if (!user?.id) {
      this.logger.warn(
        `Primary contact ${profile.userId} of company ${companyId} is not an active account`,
      );
      return null;
    }

    return { profile, user, userId: user.id };
  }

  /**
   * The portal route that trades the token for a set-password form. Params are
   * URL-encoded because the token is base64url — safe as-is, but the encoding
   * keeps this correct if the token format ever changes.
   */
  private buildResetLink(userId: string, token: string): string {
    const base = this.config.get<string>("app.portalBaseUrl");
    return `${base}/reset-password?uid=${encodeURIComponent(
      userId,
    )}&token=${encodeURIComponent(token)}`;
  }
}