import {
  BadGatewayException,
  BadRequestException,
  Injectable,
  Logger,
} from "@nestjs/common";
import { HttpService } from "@nestjs/axios";
import { AxiosError } from "axios";
import { firstValueFrom } from "rxjs";
import { logCtx } from "@edr/api-common";
import {
  InitiatePaymentRequest,
  PaymentIntentSnapshot,
  PaymentReferenceType,
  PaymentService,
} from "@edr/types";

/**
 * Thin HTTP client for the payment microservice (apps/edr-payment-api).
 * Domain validation stays in the freight API; provider calls, intents,
 * and webhooks live in the payment service.
 */
@Injectable()
export class PaymentClientService {
  private readonly logger = new Logger(PaymentClientService.name);
  private readonly baseUrl = (
    process.env.PAYMENT_API_URL ?? "https://paymentcallback.triaplc.com"
  )
    // "http://localhost:3003"
    .replace(/\/$/, "");
  private readonly serviceToken = process.env.SERVICE_AUTH_TOKEN ?? "";

  constructor(private readonly http: HttpService) { }

  /** POST /payments/initiate — idempotent per (service, referenceType, referenceId). */
  async initiate(
    request: InitiatePaymentRequest,
  ): Promise<PaymentIntentSnapshot> {
    return this.call("POST", "/payments/initiate", request);
  }

  /**
   * POST /payments/reconcile — settlement check for a domain order
   * (reconcile-before-cancel). Live-queries every non-failed intent at the
   * provider and registers any late capture found (flips it to SUCCEEDED and
   * emits payment.succeeded). `unverifiable: true` = could not confirm
   * "not paid" — the caller must NOT cancel/expire the order.
   */
  async reconcileReference(
    referenceType: PaymentReferenceType,
    referenceId: string,
  ): Promise<{ paid: boolean; unverifiable: boolean }> {
    return this.call("POST", "/payments/reconcile", {
      service: PaymentService.FREIGHT,
      referenceType,
      referenceId,
    });
  }

  /** GET /payments/intents?… — active intent by domain reference; null when none exists. */
  async getIntentByReference(
    referenceType: PaymentReferenceType,
    referenceId: string,
  ): Promise<PaymentIntentSnapshot | null> {
    const query = new URLSearchParams({
      service: PaymentService.FREIGHT,
      referenceType,
      referenceId,
    });
    try {
      return await this.call("GET", `/payments/intents?${query.toString()}`);
    } catch (err) {
      if (err instanceof AxiosError && err.response?.status === 404)
        return null;
      throw err;
    }
  }

  /**
   * POST /payments/intents/:id/confirm — submit an OTP for a COLLECT_OTP provider
   * (CAC Bank). A wrong/expired OTP comes back as 400 from the payment service;
   * surface that as a BadRequest (retryable) rather than a 502, so the payer can
   * re-enter the code.
   */
  async confirmOtp(
    intentId: string,
    otp: string,
  ): Promise<PaymentIntentSnapshot> {
    try {
      return await this.call<PaymentIntentSnapshot>(
        "POST",
        `/payments/intents/${intentId}/confirm`,
        { otp },
      );
    } catch (err) {
      // `call` re-throws raw 404s and masks every other 4xx as BadGateway; an
      // unknown intent or a bad OTP is client-fixable, so translate both to 400.
      if (err instanceof AxiosError && err.response?.status === 404) {
        throw new BadRequestException("PaymentIntent not found");
      }
      if (err instanceof BadGatewayException) {
        const detail = err.message.replace(/^Payment service error: /, "");
        throw new BadRequestException(detail);
      }
      throw err;
    }
  }

  private async call<T>(
    method: "GET" | "POST",
    path: string,
    body?: unknown,
  ): Promise<T> {
    const url = `${this.baseUrl}${path}`;
    // Every hop to the payment service lands on the request log line: which
    // call, how slow, and what it answered. A settle that never happened is
    // almost always one of these coming back 4xx/5xx or timing out.
    const startedAt = Date.now();
    const trace = (extra: Record<string, unknown>) =>
      logCtx(
        { method, path, ms: Date.now() - startedAt, ...extra },
        { path: "outbound.payment", mode: "push" },
      );

    try {
      const response = await firstValueFrom(
        this.http.request<T>({
          method,
          url,
          data: body,
          headers: this.serviceToken
            ? { "x-service-token": this.serviceToken }
            : {},
        }),
      );
      trace({ status: response.status });
      return response.data;
    } catch (err) {
      if (err instanceof AxiosError && err.response) {
        trace({ status: err.response.status });
        if (err.response.status === 404) throw err;
        const detail =
          (err.response.data as { message?: string | string[] })?.message ??
          err.message;
        this.logger.error(
          `payment service ${method} ${path} → ${err.response.status}: ${detail}`,
        );
        throw new BadGatewayException(`Payment service error: ${detail}`);
      }
      const message =
        err instanceof Error && err.message ? err.message : String(err);
      trace({ unreachable: true, error: message });
      this.logger.error(
        `payment service unreachable (${method} ${path}): ${message}`,
      );
      throw new BadGatewayException("Payment service unreachable");
    }
  }
}