MCP Time Server Node

# Verified Behavior: Business Logic Utilities **Decision Date:** 2025-01-31 16:30 EST ## Critical Analysis After deep analysis of `calculateBusinessHours` and `getBusinessDays`, the shared logic is LIMITED. These tools serve fundamentally different purposes: - **calculateBusinessHours**: Calculates actual business HOURS/MINUTES within specific time ranges - **getBusinessDays**: Counts whole DAYS (business vs weekend vs holiday) ## Verified Shared Patterns ### 1. Date Parsing with Timezone (IDENTICAL) Both tools have this exact helper: ```typescript const parseDate = (dateStr: string, fieldName: string): Date => { try { return parseTimeInput(dateStr, timezone).date; } catch (error) { throw { error: createError( TimeServerErrorCodes.INVALID_DATE_FORMAT, `Invalid ${fieldName} format: ${dateStr}`, { /* error details */ } ), }; } }; ``` ### 2. Holiday Date Parsing (SIMILAR but DIFFERENT) **calculateBusinessHours approach:** - Takes simple `holidays: string[]` array - Stores as `Date[]` for comparison - Uses `format(h, 'yyyy-MM-dd')` for date matching **getBusinessDays approach:** - Takes THREE sources: `holidays[]`, `custom_holidays[]`, `holiday_calendar` - Stores in `Set<string>` using `toDateString()` - Supports observed dates from holiday calendars - Has complex validation for calendar codes ### 3. Weekend Detection (DIFFERENT implementations) **calculateBusinessHours:** ```typescript const dayOfWeek = parseInt(formatInTimeZone(day, timezone, 'c'), 10) - 1; const isWeekendDay = dayOfWeek === 0 || dayOfWeek === 6; ``` **getBusinessDays:** ```typescript const isWeekendDay = isWeekend(day); // date-fns function ``` ## What to Extract ### 1. `parseDateWithTimezone` utility - Exact shared pattern for parsing dates with timezone and error handling - Safe to extract as it's identical in both files ### 2. `parseHolidayDates` utility (BASIC version) - Extract the common pattern of parsing an array of date strings - Each tool can extend this for their specific needs - Must preserve exact error handling ### 3. DO NOT EXTRACT - Business hours validation (specific to calculateBusinessHours) - Business hours calculations (specific to calculateBusinessHours) - Holiday calendar logic (specific to getBusinessDays) - The actual calculation logic (fundamentally different) ## Implementation Strategy 1. Create `businessUtils.ts` with: - `parseDateWithTimezone(dateStr, timezone, fieldName)` - `parseHolidayDates(dates, timezone)` - returns Date[] 2. Each tool keeps its specific logic: - calculateBusinessHours keeps minute-level calculations - getBusinessDays keeps day counting and calendar logic ## Critical Edge Cases to Preserve 1. **Timezone boundaries**: Dates parsed in business timezone 2. **Error messages**: Must maintain exact error structure 3. **Holiday comparison**: Different tools use different comparison methods 4. **Weekend detection**: Keep existing implementations (don't unify) ## Why This Approach The tools are MORE DIFFERENT than similar. Over-extracting would: - Create unnecessary abstractions - Make the code harder to understand - Risk breaking complex business logic - Not significantly improve maintainability By extracting only the truly identical patterns, we: - Improve consistency where it matters - Preserve tool-specific optimizations - Maintain clarity of purpose for each tool - Reduce risk of introducing bugs