feat(planning): explain and trace planning decisions

src/app/services/calendar-service.ts

@@ -6,6 +6,7 @@ import weekOfYear from 'dayjs/plugin/weekOfYear';
 import isoWeek from 'dayjs/plugin/isoWeek';
 import { DateCacheService } from './date-cache.service';
 import {
+	createPlanningCalculation as createPlanningCalculationOperation,
 	planLeave as planLeaveOperation,
 	LeaveType,
 	PlanOutcome,
@@ -30,14 +31,19 @@ export class CalendarService {
 	private dateCache = inject(DateCacheService);
 
 	readonly planLeave = planLeaveOperation;
+	readonly createPlanningCalculation = createPlanningCalculationOperation;
 
 	getDefaultPlanningHorizon(now = new Date()): { start: string; end: string } {
 		const start = planningDateInParis(now);
 		return { start, end: addPlanningYears(start, 1) };
 	}
 
-	selectedDatesForPlan(plan: PlanOutcome): SelectedDates {
-		const selected = this.getSelectedDatesForYear();
+	selectedDatesForPlan(
+		plan: Pick<PlanOutcome, 'placements'> & { horizon?: { start: string; end: string } },
+	): SelectedDates {
+		const selected = plan.horizon
+			? this.getSelectedDatesForHorizon(plan.horizon)
+			: this.getSelectedDatesForYear();
 		for (const placement of plan.placements) {
 			selected.push(
 				new SelectedDate(
@@ -65,8 +71,22 @@ export class CalendarService {
 	}
 
 	getSelectedDatesForYear(): SelectedDates {
-		const holidays = this.getHolidays();
-		const monthInAYear = this.monthsInAYearFromNow();
+		return this.getSelectedDatesForHorizon(this.getDefaultPlanningHorizon());
+	}
+
+	getSelectedDatesForHorizon(horizon: { start: string; end: string }): SelectedDates {
+		const start = new Date(`${horizon.start}T00:00:00`);
+		const last = new Date(`${horizon.end}T00:00:00`);
+		last.setDate(last.getDate() - 1);
+		const holidays = this.getHolidays(start.getFullYear());
+		const monthInHorizon: Year = [];
+		const cursor = new Date(start.getFullYear(), start.getMonth(), 1);
+		while (cursor <= last) {
+			monthInHorizon.push(
+				CalendarService.weeksInMonth(cursor.getMonth(), cursor.getFullYear()),
+			);
+			cursor.setMonth(cursor.getMonth() + 1);
+		}
 		const selectedDates: SelectedDates = new SelectedDates();
 
 		// Use DateCacheService to get today's date components
@@ -79,7 +99,7 @@ export class CalendarService {
 		// Create a Set of holiday timestamps for O(1) lookup instead of O(n)
 		const holidayTimestamps = new Set(holidays.map((h) => h.getTime()));
 
-		for (const weeksInAMonth of monthInAYear) {
+		for (const weeksInAMonth of monthInHorizon) {
 			for (const daysInAWeek of weeksInAMonth) {
 				for (const day of daysInAWeek) {
 					if (day) {
@@ -131,10 +151,9 @@ export class CalendarService {
 		}
 	}
 
-	getHolidays(): Date[] {
+	getHolidays(startYear = this.dateCache.getCurrentYear()): Date[] {
 		// Cache holidays to avoid recalculation
-		const currentYear = this.dateCache.getCurrentYear();
-		if (this.holidayCacheYear === currentYear && this.holidayTimestampsCache) {
+		if (this.holidayCacheYear === startYear && this.holidayTimestampsCache) {
 			// Return timestamps directly for efficient lookup
 			return Array.from(this.holidayTimestampsCache).map((ts) => new Date(ts));
 		}
@@ -142,10 +161,10 @@ export class CalendarService {
 		// Logic to return holidays for the given year
 		const hd = new Holidays('FR', allTypesOptions);
 		const holidays = hd
-			.getHolidays(currentYear, lang)
+			.getHolidays(startYear, lang)
 			.filter((holiday) => holiday.type === 'public');
 		const holidaysPlusOne = hd
-			.getHolidays(currentYear + 1, lang)
+			.getHolidays(startYear + 1, lang)
 			.filter((holiday) => holiday.type === 'public');
 		holidays.push(...holidaysPlusOne);
 		const holidaysDate: Date[] = holidays.map((holiday) => {
@@ -155,7 +174,7 @@ export class CalendarService {
 
 		// Update cache
 		this.holidayTimestampsCache = new Set(holidaysDate.map((d) => d.getTime()));
-		this.holidayCacheYear = currentYear;
+		this.holidayCacheYear = startYear;
 
 		return holidaysDate;
 	}