worklenz/worklenz-backend/src/controllers/reporting/reporting-controller-base-with-timezone.ts

import WorklenzControllerBase from "../worklenz-controller-base";
import { IWorkLenzRequest } from "../../interfaces/worklenz-request";
import db from "../../config/db";
import moment from "moment-timezone";
import { DATE_RANGES } from "../../shared/constants";

export default abstract class ReportingControllerBaseWithTimezone extends WorklenzControllerBase {
  
  /**
   * Get the user's timezone from the database or request
   * @param userId - The user ID
   * @returns The user's timezone or 'UTC' as default
   */
  protected static async getUserTimezone(userId: string): Promise<string> {
    const q = `SELECT tz.name as timezone 
               FROM users u 
               JOIN timezones tz ON u.timezone_id = tz.id 
               WHERE u.id = $1`;
    const result = await db.query(q, [userId]);
    return result.rows[0]?.timezone || 'UTC';
  }

  /**
   * Generate date range clause with timezone support
   * @param key - Date range key (e.g., YESTERDAY, LAST_WEEK)
   * @param dateRange - Array of date strings
   * @param userTimezone - User's timezone (e.g., 'America/New_York')
   * @returns SQL clause for date filtering
   */
  protected static getDateRangeClauseWithTimezone(key: string, dateRange: string[], userTimezone: string) {
    // For custom date ranges
    if (dateRange.length === 2) {
      // Convert dates to user's timezone start/end of day
      const start = moment.tz(dateRange[0], userTimezone).startOf('day');
      const end = moment.tz(dateRange[1], userTimezone).endOf('day');
      
      // Convert to UTC for database comparison
      const startUtc = start.utc().format("YYYY-MM-DD HH:mm:ss");
      const endUtc = end.utc().format("YYYY-MM-DD HH:mm:ss");
      
      if (start.isSame(end, 'day')) {
        // Single day selection
        return `AND task_work_log.created_at >= '${startUtc}'::TIMESTAMP AND task_work_log.created_at <= '${endUtc}'::TIMESTAMP`;
      }
      
      return `AND task_work_log.created_at >= '${startUtc}'::TIMESTAMP AND task_work_log.created_at <= '${endUtc}'::TIMESTAMP`;
    }

    // For predefined ranges, calculate based on user's timezone
    const now = moment.tz(userTimezone);
    let startDate, endDate;

    switch (key) {
      case DATE_RANGES.YESTERDAY:
        startDate = now.clone().subtract(1, 'day').startOf('day');
        endDate = now.clone().subtract(1, 'day').endOf('day');
        break;
      case DATE_RANGES.LAST_WEEK:
        startDate = now.clone().subtract(1, 'week').startOf('week');
        endDate = now.clone().subtract(1, 'week').endOf('week');
        break;
      case DATE_RANGES.LAST_MONTH:
        startDate = now.clone().subtract(1, 'month').startOf('month');
        endDate = now.clone().subtract(1, 'month').endOf('month');
        break;
      case DATE_RANGES.LAST_QUARTER:
        startDate = now.clone().subtract(3, 'months').startOf('day');
        endDate = now.clone().endOf('day');
        break;
      default:
        return "";
    }

    if (startDate && endDate) {
      const startUtc = startDate.utc().format("YYYY-MM-DD HH:mm:ss");
      const endUtc = endDate.utc().format("YYYY-MM-DD HH:mm:ss");
      return `AND task_work_log.created_at >= '${startUtc}'::TIMESTAMP AND task_work_log.created_at <= '${endUtc}'::TIMESTAMP`;
    }

    return "";
  }

  /**
   * Format dates for display in user's timezone
   * @param date - Date to format
   * @param userTimezone - User's timezone
   * @param format - Moment format string
   * @returns Formatted date string
   */
  protected static formatDateInTimezone(date: string | Date, userTimezone: string, format: string = "YYYY-MM-DD HH:mm:ss") {
    return moment.tz(date, userTimezone).format(format);
  }

  /**
   * Get working days count between two dates in user's timezone
   * @param startDate - Start date
   * @param endDate - End date
   * @param userTimezone - User's timezone
   * @returns Number of working days
   */
  protected static getWorkingDaysInTimezone(startDate: string, endDate: string, userTimezone: string): number {
    const start = moment.tz(startDate, userTimezone);
    const end = moment.tz(endDate, userTimezone);
    let workingDays = 0;
    
    const current = start.clone();
    while (current.isSameOrBefore(end, 'day')) {
      // Monday = 1, Friday = 5
      if (current.isoWeekday() >= 1 && current.isoWeekday() <= 5) {
        workingDays++;
      }
      current.add(1, 'day');
    }
    
    return workingDays;
  }
}