Add a nice cleanup of holidayUtils.js

src/lib/CalendarMonth.svelte

@@ -14,7 +14,6 @@
         const normalizedLocale = locale.toLowerCase() === 'us' ? 'en-US' : `en-${locale.toUpperCase()}`;
     
         try {
-            // Try to get firstDay from Intl.Locale weekInfo
             // @ts-ignore .weekInfo exists on all browsers except Firefox
             const weekFirstDay = new Intl.Locale(normalizedLocale)?.weekInfo?.firstDay;
             if (weekFirstDay !== undefined) {
@@ -101,10 +100,11 @@
         <div class="day"></div>
     {/each}
     {#each Array.from({ length: daysInMonth }, (_, i) => i + 1) as day}
-        <div class="day {isWeekend(new Date(year, month, day)) ? 'weekend' : ''} {getHoliday(day) ? 'holiday' : ''} {isOptimizedDayOff(day) ? 'optimized' : ''} {isConsecutiveDayOff(day) ? 'consecutive-day' : ''}">
-            {day}
-            {#if getHoliday(day)}
-                <Tooltip text={getHoliday(day)?.name} />
+        {@const holiday = getHoliday(day)}
+        <div class="day {isWeekend(new Date(year, month, day)) ? 'weekend' : ''} {holiday ? 'holiday' : ''} {isOptimizedDayOff(day) ? 'optimized' : ''} {isConsecutiveDayOff(day) ? 'consecutive-day' : ''}">
+            <span class={holiday?.hidden ? 'strikethrough' : ''}>{day}</span>
+            {#if holiday}
+                <Tooltip text={holiday.name} />
             {/if}
         </div>
     {/each}
@@ -197,4 +197,9 @@
             font-size: 0.8em;
         }
     }
+
+    .strikethrough {
+        text-decoration: line-through;
+        opacity: 0.5;
+    }
 </style> 

src/lib/holidayUtils.ts

@@ -1,336 +1,179 @@
 import Holidays from 'date-holidays';
 
-// Constants
 const MS_IN_A_DAY = 86400000;
 const MAX_GAP_LENGTH = 5;
 
-// Helper function to check if a date is a weekend
-const isWeekend = (date: Date, weekendDays: number[]): boolean => weekendDays.includes(date.getDay());
-
-// Helper function to check if two dates are the same day
-const isSameDay = (date1: Date, date2: Date): boolean => 
-    date1.getFullYear() === date2.getFullYear() &&
-    date1.getMonth() === date2.getMonth() &&
-    date1.getDate() === date2.getDate();
-
-// Helper function to generate a unique key for a date
+// Core date helper functions
 const dateKey = (date: Date): string => `${date.getFullYear()}-${date.getMonth()}-${date.getDate()}`;
-
-// Helper function to check if a date is a holiday
+const isWeekend = (date: Date, weekendDays: number[]): boolean => weekendDays.includes(date.getDay());
 const isHoliday = (date: Date, holidays: { date: Date }[]): boolean => holidays.some(h => dateKey(h.date) === dateKey(date));
+const daysBetween = (start: Date, end: Date): number => Math.round((end.getTime() - start.getTime()) / MS_IN_A_DAY);
 
-// Helper function to check if a date is a day off
-const isDayOff = (date: Date, allDaysOffSet: Set<string>): boolean => allDaysOffSet.has(dateKey(date));
-
-// Helper function to calculate the number of days between two dates
-const daysBetween = (startDate: Date, endDate: Date): number => Math.round((endDate.getTime() - startDate.getTime()) / MS_IN_A_DAY);
-
-// Helper function to format a date
-const formatDate = (date: Date): string => date.toLocaleDateString('en-US', { month: 'short', day: 'numeric' });
-
-// Get holidays for a specific year and country
+// Get holidays for a year, handling multi-day holidays and timezone differences
 export function getHolidaysForYear(countryCode: string, year: number, stateCode?: string): { date: Date; name: string }[] {
-    // The date-holidays lib has translations for many holidays, but defaults to using the language of the country.
-    // We can pass in the browser's preferred languages (though the lib doesn't fall back, e.g. from `de-AT` to `de`)
-    const languages = navigator.languages.map(lang => lang.split('-')[0]);
-    // Start/end dates are returned in that country/state's time zone, so we need to provide our time zone to localise
-    const opts = { languages, timezone: Intl.DateTimeFormat().resolvedOptions().timeZone };
+    // Use browser's languages and timezone to get localized holiday names
+    const opts = { 
+        languages: navigator.languages.map(lang => lang.split('-')[0]),
+        timezone: Intl.DateTimeFormat().resolvedOptions().timeZone 
+    };
     const hd = stateCode ? new Holidays(countryCode, stateCode, opts) : new Holidays(countryCode, opts);
-    console.log(hd.getHolidays(year));
+    
     return hd.getHolidays(year)
         .filter(holiday => holiday.type === 'public')
-        .flatMap(holiday =>
-            // To handle single- and multi-day holidays, we generate a holiday entry for each day in the period
-            Array.from({ length: daysBetween(holiday.start, holiday.end) }, (_, i) => ({
+        .flatMap(holiday => Array.from(
+            { length: daysBetween(holiday.start, holiday.end) }, 
+            (_, i) => ({
                 date: new Date(holiday.start.getFullYear(), holiday.start.getMonth(), holiday.start.getDate() + i),
                 name: holiday.name,
-            }))
-        )
-        .sort((holiday1, holiday2) => holiday1.date.getTime() - holiday2.date.getTime() || holiday1.name.localeCompare(holiday2.name));
+            })
+        ))
+        .sort((a, b) => a.date.getTime() - b.date.getTime() || a.name.localeCompare(b.name));
 }
 
-// Optimize days off to create the longest possible chains
-export function optimizeDaysOff(
-    holidays: { date: Date }[], 
-    year: number, 
-    daysOff: number, 
-    weekendDays: number[] = [0, 6]
-): Date[] {
-    const currentYearHolidays = holidays.filter(h => h.date.getFullYear() === year);
-    const weekends = getWeekends(year, weekendDays);
-    const allDaysOffSet = new Set([
-        ...currentYearHolidays.map(h => dateKey(h.date)),
-        ...weekends.map(d => dateKey(d))
-    ]);
-
-    let rankedGaps = rankGapsByEfficiency(
-        findGaps(allDaysOffSet, year, weekendDays), 
-        allDaysOffSet,
-        weekendDays
-    );
-
-    return selectDaysOff(rankedGaps, daysOff, allDaysOffSet, year, weekendDays);
-}
-
-// Calculate consecutive days off
-export function calculateConsecutiveDaysOff(
-    holidays: Array<{ date: Date }>,
-    optimizedDaysOff: Date[],
-    year: number,
-    weekendDays: number[] = [0, 6]
-) {
+// Find optimal placement of PTO days to maximize consecutive time off
+export function optimizeDaysOff(holidays: { date: Date }[], year: number, daysOff: number, weekendDays: number[] = [0, 6]): Date[] {
     const allDaysOff = new Set([
-        ...holidays.map(h => h.date.toISOString()),
-        ...optimizedDaysOff.map(d => d.toISOString())
+        ...holidays.filter(h => h.date.getFullYear() === year).map(h => dateKey(h.date)),
+        ...getWeekends(year, weekendDays).map(d => dateKey(d))
     ]);
 
-    // Add all weekend days for the year
-    const startDate = new Date(year, 0, 1);
-    const endDate = new Date(year, 11, 31);
-    for (let d = new Date(startDate); d <= endDate; d.setDate(d.getDate() + 1)) {
-        if (weekendDays.includes(d.getDay())) {
-            allDaysOff.add(new Date(d).toISOString());
-        }
-    }
+    const gaps = findGaps(allDaysOff, year, weekendDays);
+    return selectDaysOff(rankGapsByEfficiency(gaps, allDaysOff, weekendDays), daysOff, allDaysOff, weekendDays);
+}
 
-    const consecutiveDaysOff: { startDate: Date; endDate: Date; usedDaysOff: number; totalDays: number }[] = [];
-    let currentGroup: Date[] = [];
-    
-    for (let month = 0; month < 12; month++) {
-        for (let day = 1; day <= 31; day++) {
-            const date = new Date(year, month, day);
-            if (date.getMonth() !== month) break;
+// Calculate periods of consecutive days off (weekends + holidays + PTO)
+export function calculateConsecutiveDaysOff(holidays: { date: Date }[], optimizedDaysOff: Date[], year: number, weekendDays: number[] = [0, 6]) {
+    const allDaysOff = new Set([
+        ...holidays.map(h => dateKey(h.date)),
+        ...optimizedDaysOff.map(d => dateKey(d)),
+        ...getWeekends(year, weekendDays).map(d => dateKey(d))
+    ]);
 
-            if (isWeekend(date, weekendDays) || isHoliday(date, holidays) || allDaysOff.has(date.toISOString())) {
-                currentGroup.push(date);
-            } else {
-                if (isValidPeriod(currentGroup, weekendDays, holidays, optimizedDaysOff)) {
-                    const startDate = currentGroup[0];
-                    const endDate = currentGroup[currentGroup.length - 1];
-                    const totalDays = daysBetween(startDate, endDate) + 1;
-                    const usedDaysOff = currentGroup.filter(d => 
-                        optimizedDaysOff.some(od => 
-                            od.getFullYear() === d.getFullYear() &&
-                            od.getMonth() === d.getMonth() &&
-                            od.getDate() === d.getDate()
-                        )
-                    ).length;
+    const consecutiveDaysOff = [];
+    let currentGroup = [];
 
-                    consecutiveDaysOff.push({
-                        startDate,
-                        endDate,
-                        usedDaysOff,
-                        totalDays
-                    });
-                }
-                currentGroup = [];
+    for (let d = new Date(year, 0, 1); d <= new Date(year, 11, 31); d.setDate(d.getDate() + 1)) {
+        if (isWeekend(d, weekendDays) || isHoliday(d, holidays) || allDaysOff.has(dateKey(d))) {
+            currentGroup.push(new Date(d));
+        } else if (currentGroup.length > 0) {
+            if (hasWeekendAndNonWeekendHoliday(currentGroup, weekendDays, holidays, optimizedDaysOff)) {
+                consecutiveDaysOff.push(createPeriod(currentGroup, optimizedDaysOff));
             }
+            currentGroup = [];
         }
     }
 
-    if (isValidPeriod(currentGroup, weekendDays, holidays, optimizedDaysOff)) {
-        const startDate = currentGroup[0];
-        const endDate = currentGroup[currentGroup.length - 1];
-        const totalDays = daysBetween(startDate, endDate) + 1;
-        const usedDaysOff = currentGroup.filter(d => 
-            optimizedDaysOff.some(od => 
-                od.getFullYear() === d.getFullYear() &&
-                od.getMonth() === d.getMonth() &&
-                od.getDate() === d.getDate()
-            )
-        ).length;
-
-        consecutiveDaysOff.push({
-            startDate,
-            endDate,
-            usedDaysOff,
-            totalDays
-        });
+    if (currentGroup.length > 0 && hasWeekendAndNonWeekendHoliday(currentGroup, weekendDays, holidays, optimizedDaysOff)) {
+        consecutiveDaysOff.push(createPeriod(currentGroup, optimizedDaysOff));
     }
 
     return consecutiveDaysOff;
 }
 
-// Update the isValidPeriod function
-function isValidPeriod(
-    group: Date[], 
-    weekendDays: number[],
-    holidays: Array<{ date: Date }>,
-    optimizedDaysOff: Date[]
-): boolean {
-    if (group.length < 2) return false;
-
-    // Count weekend days
-    const weekendDates = group.filter(date => weekendDays.includes(date.getDay()));
-    if (weekendDates.length === 0) return false; // Must have at least one weekend day
-
-    // Count non-weekend days that are either holidays or PTO days
-    const nonWeekendHolidayOrPTO = group.some(date => {
-        // Skip if it's a weekend day
-        if (weekendDays.includes(date.getDay())) return false;
-
-        // Check if it's either a holiday or PTO day
-        return isHoliday(date, holidays) || 
-            optimizedDaysOff.some(od => 
-                od.getFullYear() === date.getFullYear() &&
-                od.getMonth() === date.getMonth() &&
-                od.getDate() === date.getDate()
-            );
-    });
-
-    // Must have at least one weekend day AND one non-weekend holiday/PTO day
-    return nonWeekendHolidayOrPTO;
-}
-
-// Get all weekends for a specific year
+// Get all weekend days for a year
 function getWeekends(year: number, weekendDays: number[]): Date[] {
-    const weekends: Date[] = [];
-    for (let month = 0; month < 12; month++) {
-        for (let day = 1; day <= 31; day++) {
-            const date = new Date(year, month, day);
-            if (date.getMonth() !== month) break;
-            if (isWeekend(date, weekendDays)) weekends.push(date);
+    const weekends = [];
+    for (let d = new Date(year, 0, 1); d <= new Date(year, 11, 31); d.setDate(d.getDate() + 1)) {
+        if (d.getMonth() === d.getMonth() && isWeekend(d, weekendDays)) {
+            weekends.push(new Date(d));
         }
     }
     return weekends;
 }
 
-// Find gaps between days off
-function findGaps(allDaysOffSet: Set<string>, year: number, weekendDays: number[]): { start: Date; end: Date; gapLength: number }[] {
-    const gaps: { start: Date; end: Date; gapLength: number }[] = [];
-    let currentGapStart: Date | null = null;
+// Find gaps between days off that could be filled with PTO
+function findGaps(allDaysOff: Set<string>, year: number, weekendDays: number[]) {
+    const gaps = [];
+    let gapStart = null;
 
-    for (let month = 0; month < 12; month++) {
-        for (let day = 1; day <= 31; day++) {
-            const date = new Date(year, month, day);
-            if (date.getMonth() !== month) break;
-
-            const isDayOff = allDaysOffSet.has(dateKey(date));
-
-            if (!isDayOff && !isWeekend(date, weekendDays)) {
-                if (!currentGapStart) currentGapStart = date;
-            } else if (currentGapStart) {
-                const gapLength = daysBetween(currentGapStart, date);
-                if (gapLength > 0 && gapLength <= MAX_GAP_LENGTH) {
-                    gaps.push({ start: currentGapStart, end: new Date(date.getTime() - MS_IN_A_DAY), gapLength });
-                }
-                currentGapStart = null;
+    for (let d = new Date(year, 0, 1); d <= new Date(year, 11, 31); d.setDate(d.getDate() + 1)) {
+        if (!allDaysOff.has(dateKey(d)) && !isWeekend(d, weekendDays)) {
+            if (!gapStart) gapStart = new Date(d);
+        } else if (gapStart) {
+            const gapLength = daysBetween(gapStart, d);
+            if (gapLength > 0 && gapLength <= MAX_GAP_LENGTH) {
+                gaps.push({ start: gapStart, end: new Date(d.getTime() - MS_IN_A_DAY), gapLength });
             }
+            gapStart = null;
         }
     }
-
-    if (currentGapStart) {
-        const lastDayOfYear = new Date(year, 11, 31);
-        const gapLength = daysBetween(currentGapStart, lastDayOfYear) + 1;
-        if (gapLength > 0 && gapLength <= MAX_GAP_LENGTH) {
-            gaps.push({ start: currentGapStart, end: lastDayOfYear, gapLength });
-        }
-    }
-
     return gaps;
 }
 
-// Rank gaps by efficiency
-function rankGapsByEfficiency(
-    gaps: { start: Date; end: Date; gapLength: number }[], 
-    allDaysOffSet: Set<string>,
-    weekendDays: number[] = [0, 6]
-): any[] {
-    return gaps.map(gap => {
-        const backward = calculateChain(gap.start, gap.gapLength, allDaysOffSet, 'backward', weekendDays);
-        const forward = calculateChain(gap.end, gap.gapLength, allDaysOffSet, 'forward', weekendDays);
-
-        return forward.chainLength > backward.chainLength || 
-            (forward.chainLength === backward.chainLength && forward.usedDaysOff <= backward.usedDaysOff)
-            ? { ...gap, ...forward, fillFrom: 'end' }
-            : { ...gap, ...backward, fillFrom: 'start' };
-    }).sort((a, b) => 
-        a.gapLength - b.gapLength || 
-        b.chainLength - a.chainLength || 
-        a.usedDaysOff - b.usedDaysOff
-    );
+// Rank gaps by how efficiently they can be used to create longer periods off
+function rankGapsByEfficiency(gaps: any[], allDaysOff: Set<string>, weekendDays: number[]) {
+    return gaps
+        .map(gap => {
+            const [backward, forward] = ['backward', 'forward'].map(direction => 
+                calculateChain(direction === 'backward' ? gap.start : gap.end, gap.gapLength, allDaysOff, direction as 'backward' | 'forward', weekendDays)
+            );
+            return forward.chainLength > backward.chainLength || 
+                   (forward.chainLength === backward.chainLength && forward.usedDaysOff <= backward.usedDaysOff)
+                ? { ...gap, ...forward, fillFrom: 'end' }
+                : { ...gap, ...backward, fillFrom: 'start' };
+        })
+        .sort((a, b) => a.gapLength - b.gapLength || b.chainLength - a.chainLength || a.usedDaysOff - b.usedDaysOff);
 }
 
-// Calculate potential chain length and days off used
-function calculateChain(
-    startDate: Date, 
-    gapLength: number, 
-    allDaysOffSet: Set<string>, 
-    direction: 'backward' | 'forward',
-    weekendDays: number[] = [0, 6]
-): { chainLength: number; usedDaysOff: number } {
-    let chainLength = gapLength;
-    let usedDaysOff = 0;
-    let currentDate = new Date(startDate);
-
+// Calculate potential chain length in either direction from a gap
+function calculateChain(date: Date, gapLength: number, allDaysOff: Set<string>, direction: 'backward' | 'forward', weekendDays: number[]) {
     const increment = direction === 'backward' ? -1 : 1;
-    const boundaryCheck = direction === 'backward' ? -MS_IN_A_DAY : MS_IN_A_DAY;
-
-    while (allDaysOffSet.has(dateKey(new Date(currentDate.getTime() + boundaryCheck))) || 
-           isWeekend(new Date(currentDate.getTime() + boundaryCheck), weekendDays)) {
+    let chainLength = gapLength;
+    let currentDate = new Date(date);
+    
+    while (allDaysOff.has(dateKey(new Date(currentDate.getTime() + MS_IN_A_DAY * increment))) || 
+           isWeekend(new Date(currentDate.getTime() + MS_IN_A_DAY * increment), weekendDays)) {
         chainLength++;
         currentDate.setDate(currentDate.getDate() + increment);
     }
 
-    for (let i = 0; i < gapLength; i++) {
-        const potentialDayOff = new Date(startDate);
-        potentialDayOff.setDate(potentialDayOff.getDate() + (i * increment));
-        if (!allDaysOffSet.has(dateKey(potentialDayOff)) && !isWeekend(potentialDayOff, weekendDays)) {
-            usedDaysOff++;
-        }
-    }
-
-    return { chainLength, usedDaysOff };
+    return { 
+        chainLength, 
+        usedDaysOff: Array.from({ length: gapLength }, (_, i) => {
+            const d = new Date(date);
+            d.setDate(d.getDate() + i * increment);
+            return !allDaysOff.has(dateKey(d)) && !isWeekend(d, weekendDays);
+        }).filter(Boolean).length
+    };
 }
 
-// Select days off based on ranked gaps
-function selectDaysOff(rankedGaps: any[], daysOff: number, allDaysOffSet: Set<string>, year: number, weekendDays: number[]): Date[] {
-    const selectedDays: Date[] = [];
-
-    while (daysOff > 0 && rankedGaps.length > 0) {
-        const gap = rankedGaps.shift();
+// Select optimal days off based on ranked gaps
+function selectDaysOff(rankedGaps: any[], daysOff: number, allDaysOff: Set<string>, weekendDays: number[]): Date[] {
+    const selectedDays = [];
+    let remainingDays = daysOff;
 
+    for (const gap of rankedGaps) {
+        if (remainingDays <= 0) break;
+        
         const increment = gap.fillFrom === 'start' ? 1 : -1;
         const startDate = gap.fillFrom === 'start' ? gap.start : gap.end;
 
-        for (let i = 0; i < gap.gapLength && daysOff > 0; i++) {
-            const potentialDayOff = new Date(startDate);
-            potentialDayOff.setDate(potentialDayOff.getDate() + (i * increment));
-
-            if (!allDaysOffSet.has(dateKey(potentialDayOff)) && !isWeekend(potentialDayOff, weekendDays)) {
-                selectedDays.push(potentialDayOff);
-                allDaysOffSet.add(dateKey(potentialDayOff));
-                daysOff--;
+        for (let i = 0; i < gap.gapLength && remainingDays > 0; i++) {
+            const day = new Date(startDate);
+            day.setDate(day.getDate() + (i * increment));
+            
+            if (!allDaysOff.has(dateKey(day)) && !isWeekend(day, weekendDays)) {
+                selectedDays.push(day);
+                remainingDays--;
             }
         }
-
-        const newGaps = findGaps(allDaysOffSet, year, weekendDays);
-        rankedGaps = rankGapsByEfficiency(newGaps, allDaysOffSet, weekendDays);
     }
 
     return selectedDays;
 }
 
-// Add consecutive days off to the list
-function addConsecutiveDaysOff(
-    consecutiveDaysOff: { startDate: Date; endDate: Date; usedDaysOff: number; totalDays: number }[], 
-    currentGroup: Date[], 
-    optimizedDaysOff: Date[]
-) {
-    const startDate = currentGroup[0];
-    const endDate = currentGroup[currentGroup.length - 1];
-    const totalDays = daysBetween(startDate, endDate) + 1;
-    
-    // Create a Set of optimized days off for faster lookup
-    const optimizedDaysOffSet = new Set(optimizedDaysOff.map(d => dateKey(d)));
-    
-    // Count only the days that were actually used from our PTO days
-    const usedDaysOff = currentGroup.filter(d => optimizedDaysOffSet.has(dateKey(d))).length;
+// Check if a group contains both a weekend day and a non-weekend holiday/PTO day
+function hasWeekendAndNonWeekendHoliday(group: Date[], weekendDays: number[], holidays: { date: Date }[], optimizedDaysOff: Date[]) {
+    return group.some(d => weekendDays.includes(d.getDay())) &&
+           group.some(d => !weekendDays.includes(d.getDay()) && (isHoliday(d, holidays) || optimizedDaysOff.some(od => dateKey(od) === dateKey(d))));
+}
 
-    consecutiveDaysOff.push({
-        startDate,
-        endDate,
-        usedDaysOff,
-        totalDays
-    });
+// Create a period object from a group of consecutive days
+function createPeriod(group: Date[], optimizedDaysOff: Date[]) {
+    return {
+        startDate: group[0],
+        endDate: group[group.length - 1],
+        totalDays: daysBetween(group[0], group[group.length - 1]) + 1,
+        usedDaysOff: group.filter(d => optimizedDaysOff.some(od => dateKey(od) === dateKey(d))).length
+    };
 }

src/routes/+page.svelte

@@ -253,6 +253,7 @@
     $: visibleHolidaysCount = holidays.filter(h => !h.hidden).length;
 
     function toggleWeekendDay(dayNumber: number) {
+        console.log('Toggling weekend day:', dayNumber);
         if (weekendDays.includes(dayNumber)) {
             weekendDays = weekendDays.filter(d => d !== dayNumber);
         } else {
@@ -554,7 +555,6 @@
     .content-box li {
         display: flex;
         align-items: center;
-        margin-bottom: 10px;
     }
 
     .content-box button {
@@ -603,7 +603,7 @@
         justify-content: space-between;
         padding: 8px;
         border-radius: 4px;
-        gap: 10px;
+        gap: 5px;
     }
 
     .holidays-list li:hover {
@@ -710,15 +710,6 @@
 
     <div class="content-box" id="calendar">
         <div class="calendar-key">
-            <div class="key-item">
-                <div class="key-label">
-                    <span class="color-box weekend"></span>
-                    <span>Weekend</span>
-                </div>
-                <a href="#" on:click|preventDefault={() => showWeekendSettings = !showWeekendSettings} class="edit-link">
-                    (edit)
-                </a>
-            </div>
             <div class="key-item">
                 <div class="key-label">
                     <span class="color-box optimized"></span>
@@ -736,6 +727,15 @@
                     </a>
                 {/if}
             </div>
+            <div class="key-item">
+                <div class="key-label">
+                    <span class="color-box weekend"></span>
+                    <span>Weekend</span>
+                </div>
+                <a href="#" on:click|preventDefault={() => showWeekendSettings = !showWeekendSettings} class="edit-link">
+                    (edit)
+                </a>
+            </div>
         </div>
 
         {#if showHolidaysList || showWeekendSettings}