import { BadRequestException, Body, Controller, Optional, Post } from '@nestjs/common';
import { ApiTags } from '@nestjs/swagger';
import {
  GatewayInboundAuthDto,
  GatewayInboundSubmitDto,
  GatewayPendingDeliveryQueryDto,
  GatewayDownstreamAcknowledgedDto,
  GatewayDownstreamFailureType,
  GatewayDownstreamSentDto,
  GatewayDownstreamRecoveryStatusDto,
  GatewayReceiptEventDto,
  GatewaySubmitDeadLetterDto,
  GatewaySubmitResultDto,
  GatewaySubmitSegmentResultDto,
  GatewayUplinkEventDto,
} from './send-chain.contracts';
import { SendChainService } from './send-chain.service';
import { GatewayDownstreamConnectionEventDto } from '../sms-config/sms-config.contracts';
import { SmsConfigService } from '../sms-config/sms-config.service';
import { ProtocolLogsService, type ProtocolLogInput } from '../protocol-logs/protocol-logs.service';
import { SecurityDetectionService } from '../security-detection/security-detection.service';
import { MetricsService } from '../metrics/metrics.service';

@ApiTags('gateway-events')
@Controller('gateway/events')
export class GatewayEventsController {
  constructor(
    private readonly sendChain: SendChainService,
    private readonly smsConfig: SmsConfigService,
    private readonly protocolLogs: ProtocolLogsService,
    private readonly security: SecurityDetectionService,
    @Optional() private readonly metrics?: MetricsService,
  ) {}

  @Post('submit-result')
  submitResult(@Body() body: GatewaySubmitResultDto) {
    return this.sendChain.handleSubmitResult(body);
  }

  @Post('submit-segment-result')
  submitSegmentResult(@Body() body: GatewaySubmitSegmentResultDto) {
    return this.sendChain.handleSubmitSegmentResult(body);
  }

  @Post('receipt/intake')
  receiptIntake(@Body() body: GatewayReceiptEventDto) {
    return this.trackGatewayEvent('deliver_receipt', body, () => this.sendChain.intakeReceipt(body));
  }

  @Post('receipt')
  receipt(@Body() body: GatewayReceiptEventDto) {
    return this.trackGatewayEvent('deliver_receipt', body, () => this.sendChain.handleReceipt(body));
  }

  @Post('uplink')
  uplink(@Body() body: GatewayUplinkEventDto) {
    return this.trackGatewayEvent('deliver_uplink', body, () => this.sendChain.handleUplink(body));
  }

  @Post('protocol-log')
  protocolLog(@Body() body: ProtocolLogInput) {
    const allowedPacket = (
      body.direction === 'platform_to_channel'
      && ['submit', 'deliver_resp'].includes(body.eventType)
    ) || (
      body.direction === 'channel_to_platform'
      && body.eventType === 'submit_resp'
    ) || (
      body.direction === 'platform_to_client'
      && ['submit_resp', 'deliver_receipt', 'deliver_uplink'].includes(body.eventType)
    ) || (
      body.direction === 'client_to_platform'
      && body.eventType === 'deliver_resp'
    );
    if (body.protocol !== 'cmpp' || !allowedPacket || !['success', 'failed'].includes(body.status)) {
      throw new BadRequestException('Unsupported Gateway protocol log event');
    }
    this.protocolLogs.record(body);
    return { accepted: true };
  }

  @Post('dead-letter')
  deadLetter(@Body() body: GatewaySubmitDeadLetterDto) {
    return this.sendChain.recordGatewaySubmitDeadLetter(body);
  }

  @Post('inbound/authenticate')
  async authenticateInbound(@Body() body: GatewayInboundAuthDto) {
    try {
      return await this.trackGatewayEvent('connect', body, () => this.sendChain.authenticateInboundApplication(body), 'client_to_platform');
    } catch (error) {
      if (body.remoteIp) await this.security.recordEvent({ ruleCode: 'cmpp_auth_failure', sourceIp: body.remoteIp, account: body.account, protocol: body.version ?? 'cmpp', resultCode: error instanceof Error ? error.name : 'AUTH_FAILED' }).catch(() => undefined);
      throw error;
    }
  }

  @Post('inbound/submit')
  submitInbound(@Body() body: GatewayInboundSubmitDto) {
    return this.trackGatewayEvent('submit', body, () => this.sendChain.submitInboundMessage(body), 'client_to_platform');
  }

  @Post('inbound/connection')
  inboundConnection(@Body() body: GatewayDownstreamConnectionEventDto) {
    return this.smsConfig.recordDownstreamConnectionEvent(body);
  }

  @Post('downstream/pending')
  pendingDownstream(@Body() body: GatewayPendingDeliveryQueryDto) {
    return this.sendChain.listPendingDownstreamDeliveries(body);
  }

  @Post('downstream/delivered')
  downstreamDelivered(@Body() body: { id: string }) {
    return this.sendChain.markDownstreamDeliveryDelivered(body.id);
  }

  @Post('downstream/sent')
  downstreamSent(@Body() body: GatewayDownstreamSentDto) {
    return this.sendChain.markDownstreamDeliverySent(body);
  }

  @Post('downstream/acknowledged')
  downstreamAcknowledged(@Body() body: GatewayDownstreamAcknowledgedDto) {
    return this.sendChain.acknowledgeDownstreamDelivery(body);
  }

  @Post('downstream/failed')
  downstreamFailed(@Body() body: GatewayDownstreamSentDto & { errorMessage?: string; failureType?: GatewayDownstreamFailureType }) {
    return this.sendChain.markDownstreamDeliveryFailed(body.id, body.errorMessage, body.failureType, body);
  }

  @Post('downstream/recovery-status')
  downstreamRecoveryStatus(@Body() body: GatewayDownstreamRecoveryStatusDto) {
    return this.sendChain.recordGatewayDownstreamRecoveryStatus(body);
  }

  private async trackGatewayEvent<T>(
    eventType: string,
    body: object,
    action: () => Promise<T> | T,
    direction: ProtocolLogInput['direction'] = 'channel_to_platform',
  ) {
    const startedAt = Date.now();
    const inboundMetricStartedAt = eventType === 'submit' && direction === 'client_to_platform'
      ? this.metrics?.beginCmppInboundStage()
      : undefined;
    const value = body as Record<string, unknown>;
    const common: Omit<ProtocolLogInput, 'status'> = {
      protocol: 'cmpp',
      direction,
      eventType,
      tenantId: value.tenantId as string,
      applicationId: value.applicationId as string,
      channelId: value.channelId as string,
      account: (value.account ?? value.loginAccount) as string,
      messageId: (value.messageId ?? value.platformMessageId) as string,
      gatewayMessageId: (value.gatewayMessageId ?? value.msgId ?? value.upstreamMessageId) as string,
      phone: (value.phoneNumber ?? value.srcTerminalId ?? value.destinationId) as string,
      resultCode: (value.result ?? value.submitStatus ?? value.rawStatus ?? value.status ?? value.stat) as string,
      detail: { sequenceId: value.sequenceId, connectionId: value.connectionId },
    };
    try {
      const result = await action();
      const resultValue = result && typeof result === 'object'
        ? result as Record<string, unknown>
        : {};
      this.protocolLogs.record({
        ...common,
        tenantId: (resultValue.tenantId ?? common.tenantId) as string,
        applicationId: (resultValue.applicationId ?? common.applicationId) as string,
        channelId: common.channelId ?? resultValue.channelId as string,
        account: common.account ?? resultValue.account as string,
        messageId: (resultValue.messageId ?? common.messageId) as string,
        gatewayMessageId: common.gatewayMessageId
          ?? (resultValue.gatewayMessageId ?? resultValue.msgId) as string,
        resultCode: common.resultCode
          ?? (resultValue.result ?? resultValue.status) as string,
        status: 'success',
        durationMs: Date.now() - startedAt,
      });
      if (inboundMetricStartedAt != null) {
        this.metrics?.finishCmppInboundStage(inboundMetricStartedAt, 'total', 'success');
      }
      return result;
    } catch (error) {
      this.protocolLogs.record({
        ...common,
        status: 'failed',
        durationMs: Date.now() - startedAt,
        detail: { error: error instanceof Error ? error.message : 'unknown error' },
      });
      if (inboundMetricStartedAt != null) {
        this.metrics?.finishCmppInboundStage(inboundMetricStartedAt, 'total', 'error');
      }
      throw error;
    }
  }
}