Implement iCalendar export

common/src/dateJump/GregorianJumper.tsx

@@ -1,43 +1,18 @@
 import {DateJumperProps} from './base';
 import React from 'react';
-import {gregorianJDN, jdnGregorian} from '../gregorian';
+import GregorianSelector from './GregorianSelector';
 
-export default function GregorianJumper({minJDN, maxJDN, todayJDN, onJump}: DateJumperProps): JSX.Element {
-    const {todayYear, todayMonth, todayDay, startYear, endYear} = React.useMemo(() => {
-        const [todayYear, todayMonth, todayDay] = jdnGregorian(todayJDN);
-        const [startYear] = jdnGregorian(minJDN);
-        const [endYear] = jdnGregorian(maxJDN);
-        return {todayYear, todayMonth, todayDay, startYear, endYear};
-    }, [minJDN, maxJDN, todayJDN]);
-
-    const [year, setYear] = React.useState(todayYear.toString());
-    const [month, setMonth] = React.useState(todayMonth.toString());
-    const [day, setDay] = React.useState(todayDay.toString());
-
-    const validYear = /^-?\d+$/.test(year) && startYear <= +year && +year <= endYear;
-    const validMonth = /^\d+$/.test(month) && 1 <= +month && +month <= 12;
-    const validDay = /^\d+$/.test(day) && 1 <= +day && +day <= 31;
+export default function GregorianJumper({onJump, ...props}: DateJumperProps): JSX.Element {
+    const [jdn, setJDN] = React.useState<number | undefined>();
 
     function goToGregorian(event: React.FormEvent) {
         event.preventDefault();
-
-        if (!validYear || !validMonth || !validDay)
-            return;
-
-        onJump(gregorianJDN(+year, +month, +day));
+        jdn !== undefined && onJump(jdn);
     }
 
-    return <form className="input-group" onSubmit={goToGregorian}>
+    return <form className="input-group gregorian-select" onSubmit={goToGregorian}>
         <span className="input-group-text">Gregorian<span className="hide-small">&nbsp;Date</span></span>
-        <input type="number" className={`form-control go-year ${validYear ? '' : 'is-invalid'}`}
-               onChange={e => setYear(e.target.value)} value={year}
-               min={startYear} max={endYear}/>
-        <input type="number" className={`form-control go-month ${validMonth ? '' : 'is-invalid'}`}
-               onChange={e => setMonth(e.target.value)} value={month}
-               min={1} max={12}/>
-        <input type="number" className={`form-control go-day ${validDay ? '' : 'is-invalid'}`}
-               onChange={e => setDay(e.target.value)} value={day}
-               min={1} max={31}/>
-        <button type="submit" className="form-control btn btn-primary go-button">Go</button>
+        <GregorianSelector onChange={setJDN} {...props}/>
+        <button type="submit" className="form-control btn btn-primary">Go</button>
     </form>;
 }

common/src/dateJump/GregorianSelector.tsx

@@ -0,0 +1,40 @@
+import {DateSelectorProps} from './base';
+import React from 'react';
+import {gregorianJDN, jdnGregorian} from '../gregorian';
+
+function GregorianSelector({minJDN, maxJDN, initialJDN, onChange}: DateSelectorProps): JSX.Element {
+    const {todayYear, todayMonth, todayDay, startYear, endYear} = React.useMemo(() => {
+        const [todayYear, todayMonth, todayDay] = jdnGregorian(initialJDN);
+        const [startYear] = jdnGregorian(minJDN);
+        const [endYear] = jdnGregorian(maxJDN);
+        return {todayYear, todayMonth, todayDay, startYear, endYear};
+    }, [minJDN, maxJDN, initialJDN]);
+
+    const [year, setYear] = React.useState(todayYear.toString());
+    const [month, setMonth] = React.useState(todayMonth.toString());
+    const [day, setDay] = React.useState(todayDay.toString());
+
+    const validYear = /^-?\d+$/.test(year) && startYear <= +year && +year <= endYear;
+    const validMonth = /^\d+$/.test(month) && 1 <= +month && +month <= 12;
+    const validDay = /^\d+$/.test(day) && 1 <= +day && +day <= 31;
+    const valid = validYear && validMonth && validDay;
+
+    React.useEffect(
+        () => onChange(valid ? gregorianJDN(+year, +month, +day) : undefined),
+        [onChange, year, month, day, valid],
+    );
+
+    return <>
+        <input type="number" className={`form-control year${validYear ? '' : ' is-invalid'}`}
+               onChange={e => setYear(e.target.value)} value={year}
+               min={startYear} max={endYear}/>
+        <input type="number" className={`form-control month${validMonth ? '' : ' is-invalid'}`}
+               onChange={e => setMonth(e.target.value)} value={month}
+               min={1} max={12}/>
+        <input type="number" className={`form-control day${validDay ? '' : ' is-invalid'}`}
+               onChange={e => setDay(e.target.value)} value={day}
+               min={1} max={31}/>
+    </>;
+}
+
+export default GregorianSelector;

common/src/dateJump/base.ts

@@ -1,6 +1,13 @@
-export type DateJumperProps = {
+export type BaseDateProps = {
     minJDN: number;
     maxJDN: number;
-    todayJDN: number;
+    initialJDN: number;
+};
+
+export type DateSelectorProps = BaseDateProps & {
+    onChange: (jdn: number | undefined) => void;
+};
+
+export type DateJumperProps = BaseDateProps & {
     onJump: (jdn: number) => void;
 };

common/src/ui/index.scss

@@ -43,20 +43,22 @@ nav.navbar {
   }
 }
 
+.gregorian-select {
+  .year {
+    max-width: 7em;
+  }
+
+  .month, .day {
+    max-width: 5em;
+  }
+}
+
 .navigate {
   max-width: $calendar-width;
   margin-top: $spacer;
   @include make-container();
 
-  .go-year {
-    max-width: 7em;
-  }
-
-  .go-month, .go-day {
-    max-width: 5em;
-  }
-
-  .go-button {
+  .btn-primary {
     max-width: 3em;
   }
 }

frcal/src/App.tsx

@@ -5,6 +5,7 @@ import {JulianMonth} from '@common/gregorian';
 import {TimeOfDay} from './TimeOfDay';
 import {GregorianJumper} from '@common/dateJump';
 import MonthBasedApp from '@common/ui/MonthBasedApp';
+import Export from './Export';
 
 export default class App extends MonthBasedApp<number, FrenchMonth> {
     override parseYearMonth(year: string, month: string) {
@@ -34,9 +35,14 @@ export default class App extends MonthBasedApp<number, FrenchMonth> {
 
             <div className="navigate">
                 <h4>Go to a date</h4>
-                <GregorianJumper minJDN={frStartJD} maxJDN={frEndJD} todayJDN={todayJDN}
+                <GregorianJumper minJDN={frStartJD} maxJDN={frEndJD} initialJDN={todayJDN}
                                  onJump={this.goToJDN}/>
             </div>
+
+            <div className="download">
+                <h4>Export calendar</h4>
+                <Export minJDN={frStartJD} maxJDN={frEndJD} initialJDN={todayJDN}/>
+            </div>
         </>;
     }
 }

frcal/src/Export.tsx

@@ -0,0 +1,92 @@
+import {dateName, jdnFrench} from '@common/french';
+import {jdnGregorian} from '@common/gregorian';
+import React from 'react';
+import GregorianSelector from '@common/dateJump/GregorianSelector';
+import {BaseDateProps} from '@common/dateJump/base';
+
+function zeroPad(item: unknown, width: number) {
+    const n = item + '';
+    return n.length >= width ? n : new Array(width - n.length + 1).join('0') + n;
+}
+
+
+export function* iCalStream(startJDN: number, endJDN: number): Generator<string> {
+    yield `BEGIN:VCALENDAR\r
+VERSION:2.0\r
+PRODID:-//hacksw/handcal//NONSGML v1.0//EN\r
+`;
+
+    for (let jdn = startJDN; jdn <= endJDN; ++jdn) {
+        const [gy, gm, gd] = jdnGregorian(jdn);
+        const {year: fy, month: fm, day: fd} = jdnFrench(jdn);
+        yield `BEGIN:VEVENT\r
+UID:jdn-${jdn}@frcal.qt.ax\r
+DTSTAMP:${new Date().toISOString().replace(/[-:]/g, '').replace(/\.\d+/, '')}\r
+DTSTART;VALUE=DATE:${zeroPad(gy, 4)}${zeroPad(gm, 2)}${zeroPad(gd, 2)}\r
+SUMMARY:${dateName(fm, fd)} ${fy}\r
+TRANSP:TRANSPARENT\r
+END:VEVENT\r
+`;
+    }
+
+    yield 'END:VCALENDAR\r\n';
+}
+
+function iCalBlob(startJDN: number, endJDN: number): Blob {
+    return new Blob(iCalStream(startJDN, endJDN) as any, {type: 'text/calendar'});
+}
+
+function downloadAs(url: string, name: string) {
+    const a = document.createElement('a');
+    a.href = url;
+    a.download = name;
+    a.style.display = 'none';
+    document.body.appendChild(a);
+    a.click();
+    document.body.removeChild(a);
+}
+
+type Props = BaseDateProps;
+
+export default function Export(props: Props): JSX.Element {
+    const [rangeStart, setRangeStart] = React.useState<number | undefined>();
+    const [rangeEnd, setRangeEnd] = React.useState<number | undefined>();
+
+    function doExport(event: React.FormEvent) {
+        event.preventDefault();
+
+        if (rangeStart === undefined || rangeEnd === undefined) {
+            alert('Date out of range!');
+            return;
+        }
+
+        const days = rangeEnd - rangeStart;
+        if (days > 36500 && !window.confirm(
+            `You are exporting ${days} days of calendar data. This may crash your computer. Do you want to continue?`,
+        ))
+            return;
+
+        const blob = iCalBlob(rangeStart, rangeEnd);
+        const [sy, sm, sd] = jdnGregorian(rangeStart);
+        const [ey, em, ed] = jdnGregorian(rangeEnd);
+        const startDate = `${zeroPad(sy, 4)}-${zeroPad(sm, 2)}-${zeroPad(sd, 2)}`;
+        const endDate = `${zeroPad(ey, 4)}-${zeroPad(em, 2)}-${zeroPad(ed, 2)}`;
+        downloadAs(URL.createObjectURL(blob), `frcal-${startDate}-${endDate}.ics`);
+    }
+
+    return <form onSubmit={doExport}>
+        <div className="input-group gregorian-select">
+            <span className="input-group-text">Start date</span>
+            <GregorianSelector onChange={setRangeStart} {...props}/>
+        </div>
+
+        <div className="input-group gregorian-select">
+            <span className="input-group-text">End date</span>
+            <GregorianSelector onChange={setRangeEnd} {...props} initialJDN={props.initialJDN + 365 * 5}/>
+        </div>
+
+        <button type="submit" className="form-control btn btn-primary"
+                title="Export calendar as .ics file (iCalendar format)">Export
+        </button>
+    </form>;
+}

frcal/src/index.scss

@@ -0,0 +1,30 @@
+@import '@common/ui/index.scss';
+
+.download {
+  max-width: $calendar-width;
+  margin-top: $spacer;
+  @include make-container();
+
+  .input-group-text {
+    width: 6em;
+  }
+
+  .btn-primary {
+    max-width: 5em;
+  }
+}
+
+@include media-breakpoint-up(md) {
+  .download form {
+    display: flex;
+
+    .input-group {
+      width: fit-content;
+      margin-right: $spacer / 2;
+    }
+
+    .input-group-text {
+      width: auto;
+    }
+  }
+}

frcal/src/index.tsx

@@ -1,7 +1,7 @@
 import React from 'react';
 import ReactDOM from 'react-dom';
 import 'bootstrap/js/dist/collapse';
-import '@common/ui/index.scss';
+import './index.scss';
 import App from './App';
 import reportWebVitals from '@common/ui/reportWebVitals';
 import {MobileTooltipProvider} from '@common/ui/MobileTooltip';

jcal/src/App.tsx

@@ -38,7 +38,7 @@ export default class App extends MonthBasedApp<number, JulianMonth> {
 
             <div className="navigate">
                 <h4>Go to a date</h4>
-                <GregorianJumper minJDN={START_JDN} maxJDN={END_JDN} todayJDN={todayJDN} onJump={this.goToJDN}/>
+                <GregorianJumper minJDN={START_JDN} maxJDN={END_JDN} initialJDN={todayJDN} onJump={this.goToJDN}/>
             </div>
         </>;
     }