feat: make calendar capacity recurrence-aware (Closes #1208)

frontend/week-calendar-import.js

@@ -14,6 +14,10 @@ function createWeekCalendarImport() {
       new Date(parts[0],parts[1]-1,parts[2],parts[3],parts[4],parts[5]).getTime();
     return Number.isFinite(milliseconds)?milliseconds:null;
   }
+  function dateInstant(value) {
+    const match=/^(\d{4})(\d{2})(\d{2})$/.exec(value||'');
+    return match?new Date(Number(match[1]),Number(match[2])-1,Number(match[3])).getTime():null;
+  }
   function events(source) {
     if(typeof source!=='string'||!source.includes('BEGIN:VCALENDAR'))throw new Error('Choose a valid .ics calendar file.');
     if(new TextEncoder().encode(source).length>maxBytes)throw new Error('Calendar files must be 1 MB or smaller.');
@@ -22,14 +26,66 @@ function createWeekCalendarImport() {
     lines.forEach(line=>{
       if(line==='BEGIN:VEVENT'){current={};return;}
       if(line==='END:VEVENT'){
-        if(current?.start!=null&&current?.end>current.start)result.push(current);
+        if(current?.start!=null&&current?.end>current.start&&current.status!=='CANCELLED'&&current.transparency!=='TRANSPARENT')result.push(current);
         current=null;return;
       }
       if(!current)return;
       const separator=line.indexOf(':');if(separator<0)return;
-      const name=line.slice(0,separator).split(';')[0],value=line.slice(separator+1);
-      if(name==='DTSTART')current.start=instant(value);
-      if(name==='DTEND')current.end=instant(value);
+      const property=line.slice(0,separator),name=property.split(';')[0],value=line.slice(separator+1);
+      const allDay=property.split(';').slice(1).includes('VALUE=DATE');
+      if(name==='DTSTART')current.start=allDay?dateInstant(value):instant(value);
+      if(name==='DTEND')current.end=allDay?dateInstant(value):instant(value);
+      if(name==='RRULE')current.rule=value;
+      if(name==='RDATE')current.rdates=(current.rdates||[]).concat(value.split(',').map(item=>allDay?dateInstant(item):instant(item)).filter(value=>value!=null));
+      if(name==='EXDATE')current.exdates=(current.exdates||[]).concat(value.split(',').map(item=>allDay?dateInstant(item):instant(item)).filter(value=>value!=null));
+      if(name==='STATUS')current.status=value.toUpperCase();
+      if(name==='TRANSP')current.transparency=value.toUpperCase();
+    });
+    return result;
+  }
+  function recurrenceRule(value) {
+    return Object.fromEntries(String(value||'').split(';').filter(Boolean).map(part=>part.split('=')));
+  }
+  function supportedRecurrence(value) {
+    const rule=recurrenceRule(value),keys=Object.keys(rule);
+    if(!['DAILY','WEEKLY'].includes(rule.FREQ))return false;
+    const allowed=new Set(['FREQ','COUNT','INTERVAL','UNTIL',...(rule.FREQ==='WEEKLY'?['BYDAY']:[])]);
+    if(keys.some(key=>!allowed.has(key)))return false;
+    if(rule.COUNT&&(!/^\d+$/.test(rule.COUNT)||Number(rule.COUNT)<1))return false;
+    if(rule.INTERVAL&&(!/^\d+$/.test(rule.INTERVAL)||Number(rule.INTERVAL)<1))return false;
+    if(rule.COUNT&&rule.UNTIL)return false;
+    if(rule.UNTIL&&instant(rule.UNTIL)==null&&dateInstant(rule.UNTIL)==null)return false;
+    return !rule.BYDAY||rule.BYDAY.split(',').every(day=>/^(MO|TU|WE|TH|FR|SA|SU)$/.test(day));
+  }
+  function occurrences(event,rangeEnd) {
+    const duration=event.end-event.start,excluded=new Set(event.exdates||[]);
+    if(!event.rule) {
+      return [event.start,...(event.rdates||[])].filter((start,index,all)=>start<rangeEnd&&!excluded.has(start)&&all.indexOf(start)===index)
+        .map(start=>({start,end:start+duration}));
+    }
+    const rule=recurrenceRule(event.rule);
+    if(!['DAILY','WEEKLY'].includes(rule.FREQ))return [event];
+    const count=Math.max(1,Math.min(Number(rule.COUNT)||10000,10000));
+    const result=[];
+    const weekdays={SU:0,MO:1,TU:2,WE:3,TH:4,FR:5,SA:6};
+    const selected=new Set((rule.BYDAY||'').split(',').map(day=>weekdays[day]).filter(day=>day!=null));
+    if(rule.FREQ==='WEEKLY'&&!selected.size)selected.add(new Date(event.start).getDay());
+    const interval=Math.max(1,Number(rule.INTERVAL)||1),origin=new Date(event.start);
+    const until=rule.UNTIL?(instant(rule.UNTIL)??dateInstant(rule.UNTIL)):null;
+    const originDay=Date.UTC(origin.getFullYear(),origin.getMonth(),origin.getDate());
+    let start=event.start,matched=0;
+    while(start<rangeEnd&&matched<count&&(until==null||start<=until)) {
+      const cursor=new Date(start),cursorDay=Date.UTC(cursor.getFullYear(),cursor.getMonth(),cursor.getDate());
+      const weeks=Math.floor((cursorDay-originDay)/(7*24*60*60*1000));
+      const matches=rule.FREQ==='DAILY'||(weeks%interval===0&&selected.has(cursor.getDay()));
+      if(matches) {
+        matched+=1;
+        if(!excluded.has(start))result.push({start,end:start+duration});
+      }
+      cursor.setDate(cursor.getDate()+(rule.FREQ==='DAILY'?interval:1));start=cursor.getTime();
+    }
+    (event.rdates||[]).forEach(extra=>{
+      if(extra<rangeEnd&&!excluded.has(extra)&&!result.some(item=>item.start===extra))result.push({start:extra,end:extra+duration});
     });
     return result;
   }
@@ -41,8 +97,11 @@ function createWeekCalendarImport() {
     if(!Array.isArray(dates)||dates.length!==7)throw new Error('Week Ahead must contain seven dates.');
     const startMinute=clock(workdayStart),endMinute=clock(workdayEnd);
     if(startMinute==null||endMinute==null||endMinute<=startMinute)throw new Error('Working hours must end after they start.');
-    const calendarEvents=events(source);
-    return dates.map(plan_date=>{
+    const parsedEvents=events(source),rangeStart=dayBoundary(dates[0],0),rangeEnd=dayBoundary(dates[6],24*60);
+    const unsupported_count=parsedEvents.filter(event=>event.rule&&!supportedRecurrence(event.rule)&&
+      event.start<rangeEnd&&(event.end>rangeStart||event.rule)).length;
+    const calendarEvents=parsedEvents.flatMap(event=>occurrences(event,rangeEnd));
+    const days=dates.map(plan_date=>{
       const start=dayBoundary(plan_date,startMinute),end=dayBoundary(plan_date,endMinute);
       const ranges=calendarEvents.map(event=>[Math.max(start,event.start),Math.min(end,event.end)])
         .filter(range=>range[1]>range[0]).sort((left,right)=>left[0]-right[0]);
@@ -55,6 +114,8 @@ function createWeekCalendarImport() {
       const busy_minutes=Math.round(merged.reduce((total,range)=>total+range[1]-range[0],0)/60000);
       return {plan_date,busy_minutes,capacity_minutes:endMinute-startMinute-busy_minutes};
     });
+    days.unsupported_count=unsupported_count;
+    return days;
   }
   function createWorkflow({controller,qs,onApplied=()=>{}}={}) {
     let reviewed=null;
@@ -64,6 +125,7 @@ function createWeekCalendarImport() {
       qs('#week-capacity-file').value='';
       qs('#week-capacity-review').hidden=true;
       qs('#week-capacity-days').innerHTML='';
+      qs('#apply-week-capacities').disabled=false;
     }
     function open() {
       clear();root().hidden=false;qs('#week-capacity-status').textContent='';
@@ -78,11 +140,15 @@ function createWeekCalendarImport() {
         display[index].label+'</strong><span>'+day.capacity_minutes+' min available</span><small>'+day.busy_minutes+
         ' min busy during working hours</small></article>').join('');
       qs('#week-capacity-review').hidden=false;
-      qs('#week-capacity-status').textContent='Review seven capacity totals. Calendar details stay on this device.';
+      const unsupported=reviewed.unsupported_count||0;
+      qs('#apply-week-capacities').disabled=unsupported>0;
+      qs('#week-capacity-status').textContent=unsupported?
+        unsupported+' recurring event'+(unsupported===1?'':'s')+' could not be counted. Apply is unavailable; export a simpler seven-day calendar and try again.':
+        'Review seven capacity totals. Calendar details stay on this device.';
       return reviewed.map(day=>({...day}));
     }
     async function apply() {
-      if(!reviewed||!controller.stageCapacities(reviewed))return false;
+      if(!reviewed||reviewed.unsupported_count||!controller.stageCapacities(reviewed))return false;
       qs('#apply-week-capacities').disabled=true;
       try {await controller.flush();cancel();onApplied();return true;}
       finally {qs('#apply-week-capacities').disabled=false;}