import { Injectable, Inject, BadRequestException } from "@nestjs/common";
import { Logger } from "nestjs-pino";
import { ConfigService } from "@nestjs/config";
import { FreebitOrchestratorService } from "@bff/integrations/freebit/services/freebit-orchestrator.service.js";
import { WhmcsClientService } from "@bff/integrations/whmcs/services/whmcs-client.service.js";
import { MappingsService } from "@bff/modules/id-mappings/mappings.service.js";
import { SalesforceOpportunityService } from "@bff/integrations/salesforce/services/salesforce-opportunity.service.js";
import { SalesforceCaseService } from "@bff/integrations/salesforce/services/salesforce-case.service.js";
import { SimValidationService } from "./sim-validation.service.js";
import type {
  SimCancelRequest,
  SimCancelFullRequest,
  SimCancellationMonth,
  SimCancellationPreview,
} from "@customer-portal/domain/sim";
import { SALESFORCE_CASE_ORIGIN } from "@customer-portal/domain/support/providers";
import { SIM_CANCELLATION_NOTICE } from "@customer-portal/domain/opportunity";
import { SimScheduleService } from "./sim-schedule.service.js";
import { SimActionRunnerService } from "./sim-action-runner.service.js";
import { SimApiNotificationService } from "./sim-api-notification.service.js";
import { NotificationService } from "@bff/modules/notifications/notifications.service.js";
import { NOTIFICATION_SOURCE, NOTIFICATION_TYPE } from "@customer-portal/domain/notifications";

@Injectable()
export class SimCancellationService {
  constructor(
    private readonly freebitService: FreebitOrchestratorService,
    private readonly whmcsClientService: WhmcsClientService,
    private readonly mappingsService: MappingsService,
    private readonly opportunityService: SalesforceOpportunityService,
    private readonly caseService: SalesforceCaseService,
    private readonly simValidation: SimValidationService,
    private readonly simSchedule: SimScheduleService,
    private readonly simActionRunner: SimActionRunnerService,
    private readonly apiNotification: SimApiNotificationService,
    private readonly notifications: NotificationService,
    private readonly configService: ConfigService,
    @Inject(Logger) private readonly logger: Logger
  ) {}

  private get freebitBaseUrl(): string {
    return this.configService.get<string>("FREEBIT_BASE_URL") || "https://i1.mvno.net/emptool/api";
  }

  /**
   * Generate available cancellation months (next 12 months)
   */
  private generateCancellationMonths(): SimCancellationMonth[] {
    const months: SimCancellationMonth[] = [];
    const today = new Date();
    const dayOfMonth = today.getDate();

    // Start from current month if before 25th, otherwise next month
    const startOffset = dayOfMonth <= 25 ? 0 : 1;

    for (let i = startOffset; i < startOffset + 12; i++) {
      const date = new Date(today.getFullYear(), today.getMonth() + i, 1);
      const year = date.getFullYear();
      const month = date.getMonth() + 1;
      const monthStr = String(month).padStart(2, "0");

      // runDate is the 1st of the NEXT month (cancellation takes effect at month end)
      const nextMonth = new Date(year, month, 1);
      const runYear = nextMonth.getFullYear();
      const runMonth = String(nextMonth.getMonth() + 1).padStart(2, "0");

      months.push({
        value: `${year}-${monthStr}`,
        label: date.toLocaleDateString("en-US", { month: "long", year: "numeric" }),
        runDate: `${runYear}${runMonth}01`,
      });
    }

    return months;
  }

  /**
   * Calculate minimum contract end date (3 months after start, signup month not included)
   */
  private calculateMinimumContractEndDate(startDateStr: string): Date | null {
    if (!startDateStr || startDateStr.length < 8) return null;

    // Parse YYYYMMDD format
    const year = parseInt(startDateStr.substring(0, 4), 10);
    const month = parseInt(startDateStr.substring(4, 6), 10) - 1;
    const day = parseInt(startDateStr.substring(6, 8), 10);

    if (isNaN(year) || isNaN(month) || isNaN(day)) return null;

    const startDate = new Date(year, month, day);
    // Minimum term is 3 months after signup month (signup month not included)
    // e.g., signup in January = minimum term ends April 30
    const endDate = new Date(startDate.getFullYear(), startDate.getMonth() + 4, 0);

    return endDate;
  }

  /**
   * Get cancellation preview with available months
   */
  async getCancellationPreview(
    userId: string,
    subscriptionId: number
  ): Promise<SimCancellationPreview> {
    const validation = await this.simValidation.validateSimSubscription(userId, subscriptionId);
    const simDetails = await this.freebitService.getSimDetails(validation.account);

    // Get customer info from WHMCS
    const whmcsClientId = await this.mappingsService.getWhmcsClientIdOrThrow(userId);
    const clientDetails = await this.whmcsClientService.getClientDetails(whmcsClientId);
    const customerName =
      `${clientDetails.firstname || ""} ${clientDetails.lastname || ""}`.trim() || "Customer";
    const customerEmail = clientDetails.email || "";

    // Calculate minimum contract end date
    const startDate = simDetails.startDate;
    const minEndDate = startDate ? this.calculateMinimumContractEndDate(startDate) : null;
    const today = new Date();
    const isWithinMinimumTerm = minEndDate ? today < minEndDate : false;

    // Format minimum contract end date for display
    let minimumContractEndDate: string | undefined;
    if (minEndDate) {
      const year = minEndDate.getFullYear();
      const month = String(minEndDate.getMonth() + 1).padStart(2, "0");
      minimumContractEndDate = `${year}-${month}`;
    }

    return {
      simNumber: validation.account,
      serialNumber: simDetails.iccid,
      planCode: simDetails.planCode,
      startDate,
      minimumContractEndDate,
      isWithinMinimumTerm,
      availableMonths: this.generateCancellationMonths(),
      customerEmail,
      customerName,
    };
  }

  /**
   * Cancel SIM service (legacy)
   */
  async cancelSim(
    userId: string,
    subscriptionId: number,
    request: SimCancelRequest = {}
  ): Promise<void> {
    let account = "";

    await this.simActionRunner.run(
      "Cancel SIM",
      {
        baseContext: {
          userId,
          subscriptionId,
          scheduledAt: request.scheduledAt,
        },
        enrichSuccess: result => ({
          account: result.account,
          runDate: result.runDate,
        }),
        enrichError: () => ({
          account,
        }),
      },
      async () => {
        const validation = await this.simValidation.validateSimSubscription(userId, subscriptionId);
        account = validation.account;

        const scheduleResolution = this.simSchedule.resolveScheduledDate(request.scheduledAt);

        await this.freebitService.cancelSim(account, scheduleResolution.date);

        this.logger.log(`Successfully cancelled SIM for subscription ${subscriptionId}`, {
          userId,
          subscriptionId,
          account,
          runDate: scheduleResolution.date,
        });

        return {
          account,
          runDate: scheduleResolution.date,
        };
      }
    );
  }

  /**
   * Cancel SIM service with full flow (PA02-04, Salesforce Case + Opportunity, and email notifications)
   *
   * Flow:
   * 1. Validate SIM subscription
   * 2. Call Freebit PA02-04 API to schedule cancellation
   * 3. Create Salesforce Case with all form details
   * 4. Update Salesforce Opportunity (if linked)
   * 5. Send email notifications
   */
  async cancelSimFull(
    userId: string,
    subscriptionId: number,
    request: SimCancelFullRequest
  ): Promise<void> {
    const mapping = await this.mappingsService.findByUserId(userId);
    if (!mapping?.whmcsClientId || !mapping?.sfAccountId) {
      throw new BadRequestException("Account mapping not found");
    }

    const validation = await this.simValidation.validateSimSubscription(userId, subscriptionId);
    const account = validation.account;
    const simDetails = await this.freebitService.getSimDetails(account);

    // Get customer info from WHMCS
    const clientDetails = await this.whmcsClientService.getClientDetails(mapping.whmcsClientId);
    const customerName =
      `${clientDetails.firstname || ""} ${clientDetails.lastname || ""}`.trim() || "Customer";
    const customerEmail = clientDetails.email || "";

    // Validate confirmations
    if (!request.confirmRead || !request.confirmCancel) {
      throw new BadRequestException("You must confirm both checkboxes to proceed");
    }

    // Parse cancellation month and calculate runDate
    const [year, month] = request.cancellationMonth.split("-").map(Number);
    if (!year || !month) {
      throw new BadRequestException("Invalid cancellation month format");
    }

    // runDate is 1st of the NEXT month (cancellation at end of selected month)
    const nextMonth = new Date(year, month, 1);
    const runYear = nextMonth.getFullYear();
    const runMonth = String(nextMonth.getMonth() + 1).padStart(2, "0");
    const runDate = `${runYear}${runMonth}01`;

    // Calculate the cancellation date (last day of selected month)
    const lastDayOfMonth = new Date(year, month, 0);
    const cancellationDate = [
      lastDayOfMonth.getFullYear(),
      String(lastDayOfMonth.getMonth() + 1).padStart(2, "0"),
      String(lastDayOfMonth.getDate()).padStart(2, "0"),
    ].join("-");

    this.logger.log(`Processing SIM cancellation via PA02-04`, {
      userId,
      subscriptionId,
      account,
      cancellationMonth: request.cancellationMonth,
      runDate,
    });

    // Call PA02-04 cancellation API
    await this.freebitService.cancelAccount(account, runDate);

    this.logger.log(`Successfully cancelled SIM for subscription ${subscriptionId}`, {
      userId,
      subscriptionId,
      account,
      runDate,
    });

    // Find existing Opportunity for this subscription (by WHMCS Service ID)
    let opportunityId: string | null = null;
    try {
      opportunityId = await this.opportunityService.findOpportunityByWhmcsServiceId(subscriptionId);
    } catch {
      this.logger.warn("Could not find Opportunity for SIM subscription", { subscriptionId });
    }

    // Build description with all form data (same pattern as Internet)
    const descriptionLines = [
      `Cancellation Request from Portal`,
      ``,
      `Product Type: SIM`,
      `SIM Number: ${account}`,
      `Serial Number: ${simDetails.iccid || "N/A"}`,
      `WHMCS Service ID: ${subscriptionId}`,
      `Cancellation Month: ${request.cancellationMonth}`,
      `Service End Date: ${cancellationDate}`,
      ``,
    ];

    if (request.comments) {
      descriptionLines.push(`Customer Comments:`, request.comments, ``);
    }

    descriptionLines.push(`Submitted: ${new Date().toISOString()}`);

    // Create Salesforce Case for cancellation (same as Internet)
    let caseId: string | undefined;
    try {
      const caseResult = await this.caseService.createCase({
        accountId: mapping.sfAccountId,
        opportunityId: opportunityId || undefined,
        subject: `Cancellation Request - SIM (${request.cancellationMonth})`,
        description: descriptionLines.join("\n"),
        origin: SALESFORCE_CASE_ORIGIN.PORTAL_NOTIFICATION,
        priority: "High",
      });
      caseId = caseResult.id;

      this.logger.log("SIM cancellation case created", {
        caseId,
        opportunityId,
      });
    } catch (error) {
      // Log but don't fail - Freebit API was already called successfully
      this.logger.error("Failed to create SIM cancellation Case", {
        error: error instanceof Error ? error.message : String(error),
        subscriptionId,
      });
    }

    // Update Salesforce Opportunity (if linked via WHMCS_Service_ID__c)
    if (opportunityId) {
      try {
        const cancellationData = {
          scheduledCancellationDate: `${cancellationDate}T23:59:59.000Z`,
          cancellationNotice: SIM_CANCELLATION_NOTICE.RECEIVED,
        };

        await this.opportunityService.updateSimCancellationData(opportunityId, cancellationData);

        this.logger.log("Opportunity updated with SIM cancellation data", {
          opportunityId,
          scheduledDate: cancellationDate,
        });
      } catch (error) {
        // Log but don't fail - Freebit API was already called successfully
        this.logger.warn("Failed to update Opportunity with SIM cancellation data", {
          error: error instanceof Error ? error.message : String(error),
          subscriptionId,
          opportunityId,
        });
      }
    } else {
      this.logger.debug("No Opportunity linked to SIM subscription", { subscriptionId });
    }

    try {
      await this.notifications.createNotification({
        userId,
        type: NOTIFICATION_TYPE.CANCELLATION_SCHEDULED,
        source: NOTIFICATION_SOURCE.SYSTEM,
        sourceId: caseId || opportunityId || `sim:${subscriptionId}:${runDate}`,
        actionUrl: `/account/services/${subscriptionId}`,
      });
    } catch (error) {
      this.logger.warn("Failed to create SIM cancellation notification", {
        userId,
        subscriptionId,
        account,
        runDate,
        error: error instanceof Error ? error.message : String(error),
      });
    }

    // Send admin notification email
    const adminEmailBody = this.apiNotification.buildCancellationAdminEmail({
      customerName,
      simNumber: account,
      serialNumber: simDetails.iccid,
      cancellationMonth: request.cancellationMonth,
      registeredEmail: customerEmail,
      comments: request.comments,
    });

    await this.apiNotification.sendApiResultsEmail(
      "SonixNet SIM Online Cancellation",
      [
        {
          url: `${this.freebitBaseUrl}/master/cnclAcnt/`,
          json: {
            kind: "MVNO",
            account,
            runDate,
            authKey: "[REDACTED]",
          },
          result: {
            resultCode: "100",
            status: { message: "OK", statusCode: "200" },
          },
        },
      ],
      adminEmailBody
    );

    // Send confirmation email to customer
    const confirmationSubject = "SonixNet SIM Cancellation Confirmation";
    const confirmationBody = `Dear ${customerName},

Your cancellation request for SIM #${account} has been confirmed.

The cancellation will take effect at the end of ${request.cancellationMonth}.

If you have any questions, please contact us at info@asolutions.co.jp

With best regards,
Assist Solutions Customer Support
TEL: 0120-660-470 (Mon-Fri / 10AM-6PM)
Email: info@asolutions.co.jp`;

    await this.apiNotification.sendCustomerEmail(
      customerEmail,
      confirmationSubject,
      confirmationBody
    );
  }
}