import { Injectable, Logger } from "@nestjs/common";
import { InjectModel } from "@nestjs/mongoose";
import { Model } from "mongoose";
import { resolveFanavaranClientKey } from "src/core/config/fanavaran-client.config";
import { buildParsianTemplateMessage } from "../../provider/parsian-template-messages";
import {
  describeSmsError,
  SmsProviderException,
  SmsTransportException,
} from "../../provider/sms-provider.exception";
import { getSmsProvider } from "../../provider/sms-provider.config";
import type {
  SendMessage,
  VerifyLookUpMessage,
} from "../../provider/sms-gateway.types";
import { KAVENEGAR_SMS_SENDER } from "../../provider/kavenegar-sender";
import {
  SmsSendLog,
  SmsSendLogDocument,
  SmsSendLogKind,
  SmsSendLogOperation,
  SmsSendLogProvider,
  SmsSendLogStatus,
} from "../schema/sms-send-log.schema";

export type RecordSmsSendLogInput = {
  receptor: string;
  provider: SmsSendLogProvider;
  sender?: string;
  operation: SmsSendLogOperation;
  status: SmsSendLogStatus;
  kind: SmsSendLogKind;
  messageText?: string;
  template?: string;
  tokens?: {
    token?: string;
    token2?: string;
    token3?: string;
    token10?: string;
  };
  isOtp?: boolean;
  tenant?: string;
  providerResponse?: unknown;
  errorMessage?: string;
  errorDetails?: Record<string, unknown>;
  durationMs?: number;
};

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

  constructor(
    @InjectModel(SmsSendLog.name)
    private readonly smsSendLogModel: Model<SmsSendLogDocument>,
  ) {}

  /** Persist one SMS attempt; never throws (mirrors Fanavaran audit). */
  async record(input: RecordSmsSendLogInput): Promise<void> {
    try {
      await this.smsSendLogModel.create({
        receptor: input.receptor,
        provider: input.provider,
        sender: input.sender,
        operation: input.operation,
        status: input.status,
        kind: input.kind,
        messageText: input.messageText,
        template: input.template,
        tokens: input.tokens,
        isOtp: input.isOtp,
        tenant: input.tenant ?? resolveFanavaranClientKey(),
        providerResponse: input.providerResponse,
        errorMessage: input.errorMessage,
        errorDetails: input.errorDetails,
        durationMs: input.durationMs,
      });
    } catch (error) {
      this.logger.error(
        `Failed to persist SMS send log receptor=${input.receptor} status=${input.status}`,
        error,
      );
    }
  }

  activeGatewayProvider(): SmsSendLogProvider {
    return getSmsProvider() === "parsian"
      ? SmsSendLogProvider.PARSIAN
      : SmsSendLogProvider.KAVENEGAR;
  }

  senderForProvider(provider: SmsSendLogProvider): string | undefined {
    if (provider === SmsSendLogProvider.KAVENEGAR) {
      return KAVENEGAR_SMS_SENDER;
    }
    return undefined;
  }

  isAuthOtp(data: Pick<VerifyLookUpMessage, "template" | "isOtp">): boolean {
    if (data.isOtp === true) {
      return true;
    }
    const auth = process.env.AUTH_SMS_TEMPLATE?.trim();
    return Boolean(auth && data.template && data.template === auth);
  }

  resolveMessageTextForLookup(data: VerifyLookUpMessage): string {
    return buildParsianTemplateMessage(data);
  }

  async recordGatewaySend(params: {
    data: SendMessage;
    startedAt: number;
    result?: unknown;
    error?: unknown;
  }): Promise<void> {
    const provider = this.activeGatewayProvider();
    const durationMs = Date.now() - params.startedAt;

    if (params.error == null) {
      await this.record({
        receptor: params.data.receptor,
        provider,
        sender: this.senderForProvider(provider),
        operation: SmsSendLogOperation.SEND,
        status: SmsSendLogStatus.SUCCESS,
        kind: SmsSendLogKind.PLAIN,
        messageText: params.data.message,
        providerResponse: params.result,
        durationMs,
      });
      return;
    }

    await this.record({
      receptor: params.data.receptor,
      provider,
      sender: this.senderForProvider(provider),
      operation: SmsSendLogOperation.SEND,
      status: SmsSendLogStatus.FAILURE,
      kind: SmsSendLogKind.PLAIN,
      messageText: params.data.message,
      ...this.errorFields(params.error),
      durationMs,
    });
  }

  async recordGatewayVerifyLookup(params: {
    data: VerifyLookUpMessage;
    startedAt: number;
    result?: unknown;
    error?: unknown;
  }): Promise<void> {
    const provider = this.activeGatewayProvider();
    const durationMs = Date.now() - params.startedAt;
    const isOtp = this.isAuthOtp(params.data);
    const tokens = {
      token: params.data.token,
      ...(params.data.token2 != null ? { token2: params.data.token2 } : {}),
      ...(params.data.token3 != null ? { token3: params.data.token3 } : {}),
      ...(params.data.token10 != null ? { token10: params.data.token10 } : {}),
    };
    const messageText = this.resolveMessageTextForLookup(params.data);
    const kind = isOtp ? SmsSendLogKind.OTP : SmsSendLogKind.TEMPLATE;

    if (params.error == null) {
      await this.record({
        receptor: params.data.receptor,
        provider,
        sender: this.senderForProvider(provider),
        operation: SmsSendLogOperation.VERIFY_LOOKUP,
        status: SmsSendLogStatus.SUCCESS,
        kind,
        messageText,
        template: params.data.template,
        tokens,
        isOtp,
        providerResponse: params.result,
        durationMs,
      });
      return;
    }

    await this.record({
      receptor: params.data.receptor,
      provider,
      sender: this.senderForProvider(provider),
      operation: SmsSendLogOperation.VERIFY_LOOKUP,
      status: SmsSendLogStatus.FAILURE,
      kind,
      messageText,
      template: params.data.template,
      tokens,
      isOtp,
      ...this.errorFields(params.error),
      durationMs,
    });
  }

  /** FAKE_OTP / local path — no external gateway call. */
  async recordSkippedOtp(params: {
    receptor: string;
    otp: string;
    reason?: string;
  }): Promise<void> {
    const authMessage =
      process.env.AUTH_SMS_MESSAGE?.trim() ??
      "کاربر محترم رمز یکبار مصرف شما:\nCode: {token}";
    const messageText = authMessage.split("{token}").join(params.otp);

    await this.record({
      receptor: params.receptor,
      provider: SmsSendLogProvider.TEJARATNO,
      operation: SmsSendLogOperation.SKIPPED,
      status: SmsSendLogStatus.SKIPPED,
      kind: SmsSendLogKind.SKIPPED,
      messageText,
      template: process.env.AUTH_SMS_TEMPLATE?.trim() || undefined,
      tokens: { token: params.otp },
      isOtp: true,
      errorMessage: params.reason ?? "FAKE_OTP enabled — SMS provider not called",
    });
  }

  private errorFields(error: unknown): {
    errorMessage: string;
    errorDetails?: Record<string, unknown>;
    providerResponse?: unknown;
  } {
    if (error instanceof SmsProviderException) {
      return {
        errorMessage: describeSmsError(error),
        providerResponse: error.meta.providerBody,
        errorDetails: {
          operation: error.operation,
          normalized: error.meta.normalized,
        },
      };
    }
    if (error instanceof SmsTransportException) {
      return {
        errorMessage: describeSmsError(error),
        errorDetails: {
          operation: error.operation,
          cause:
            error.causeUnknown instanceof Error
              ? {
                  name: error.causeUnknown.name,
                  message: error.causeUnknown.message,
                }
              : error.causeUnknown,
        },
      };
    }
    return {
      errorMessage: describeSmsError(error),
    };
  }
}