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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Shared Sunlight</title>
<script crossorigin src="https://unpkg.com/react@18/umd/react.production.min.js"></script>
<script crossorigin src="https://unpkg.com/react-dom@18/umd/react-dom.production.min.js"></script>
<script src="https://unpkg.com/@babel/standalone/babel.min.js"></script>
<script src="https://cdn.tailwindcss.com"></script>
</head>
<body class="bg-zinc-900">
<div id="root"></div>
<script type="text/babel">
const { useState, useEffect, useMemo } = React;
// Lucide icons as inline SVG
const Sun = ({ className = "", size = 24 }) => (
<svg className={className} width={size} height={size} viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2">
<circle cx="12" cy="12" r="5"/>
<line x1="12" y1="1" x2="12" y2="3"/>
<line x1="12" y1="21" x2="12" y2="23"/>
<line x1="4.22" y1="4.22" x2="5.64" y2="5.64"/>
<line x1="18.36" y1="18.36" x2="19.78" y2="19.78"/>
<line x1="1" y1="12" x2="3" y2="12"/>
<line x1="21" y1="12" x2="23" y2="12"/>
<line x1="4.22" y1="19.78" x2="5.64" y2="18.36"/>
<line x1="18.36" y1="5.64" x2="19.78" y2="4.22"/>
</svg>
);
const Moon = ({ className = "", size = 24 }) => (
<svg className={className} width={size} height={size} viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2">
<path d="M21 12.79A9 9 0 1 1 11.21 3 7 7 0 0 0 21 12.79z"/>
</svg>
);
const ChevronLeft = ({ className = "", size = 24 }) => (
<svg className={className} width={size} height={size} viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2">
<polyline points="15 18 9 12 15 6"/>
</svg>
);
const ChevronRight = ({ className = "", size = 24 }) => (
<svg className={className} width={size} height={size} viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2">
<polyline points="9 18 15 12 9 6"/>
</svg>
);
const Share = ({ className = "", size = 24 }) => (
<svg className={className} width={size} height={size} viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2">
<circle cx="18" cy="5" r="3"/>
<circle cx="6" cy="12" r="3"/>
<circle cx="18" cy="19" r="3"/>
<line x1="8.59" y1="13.51" x2="15.42" y2="17.49"/>
<line x1="15.41" y1="6.51" x2="8.59" y2="10.49"/>
</svg>
);
const Clock = ({ className = "", size = 24 }) => (
<svg className={className} width={size} height={size} viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2">
<circle cx="12" cy="12" r="10"/>
<polyline points="12 6 12 12 16 14"/>
</svg>
);
// Constants
const MATCH_THRESHOLD = 0.25; // 15 minutes in decimal hours
const GRID_STEP = 3; // degrees
const LAT_MIN = -87;
const LAT_MAX = 87;
// Land/sea grid - complete data
const landSeaGrid = [
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[0,0,0,0,0,0,0,0,1,1,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,0,0,1,0,0,1,1,1,1,1,1,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,1,0,1,1,0,0,0,0,0,0,0],
[1,1,1,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,1,1,1,1,0,0,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1],
[0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,1,0,0,0,1,1,0,0,0,0,0,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0],
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[1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1],
];
function SharedSunlight() {
const LAT_MIN = -87;
const LAT_MAX = 87;
const presetLocations = [
{ lat: 71.2906, lng: -156.7886, name: 'Utqiagvik, US' },
{ lat: 49.2827, lng: -123.1207, name: 'Vancouver, CA' },
{ lat: 33.4484, lng: -112.0740, name: 'Phoenix, US' },
{ lat: 4.7110, lng: -74.0721, name: 'Bogotá, CO' },
{ lat: 44.2531, lng: -73.1651, name: 'Monkton, US' },
{ lat: 40.6782, lng: -73.9442, name: 'Brooklyn, US' },
{ lat: 42.3736, lng: -71.1097, name: 'Cambridge, US' },
{ lat: -54.8019, lng: -68.3030, name: 'Ushuaia, AR' },
{ lat: -23.5505, lng: -46.6333, name: 'São Paulo, BR' },
{ lat: 52.2053, lng: 0.1218, name: 'Cambridge, GB' },
{ lat: 56.1629, lng: 10.2039, name: 'Aarhus, DK' },
{ lat: 45.6495, lng: 13.7768, name: 'Trieste, IT' },
{ lat: 43.3438, lng: 17.8078, name: 'Mostar, BiH' },
{ lat: -33.9249, lng: 18.4241, name: 'Cape Town, ZA' },
{ lat: 31.5, lng: 34.4667, name: 'Gaza, PS' },
{ lat: -1.2864, lng: 36.8172, name: 'Nairobi, KE' },
{ lat: 42.8746, lng: 74.5698, name: 'Bishkek, KG' },
{ lat: 23.0225, lng: 72.5714, name: 'Ahmedabad, IN' },
{ lat: 6.9271, lng: 79.8612, name: 'Colombo, LK' },
{ lat: -31.9505, lng: 115.8605, name: 'Perth, AU' },
{ lat: 31.6536, lng: 120.7522, name: 'Changshu, CN' },
{ lat: 14.5995, lng: 120.9842, name: 'Manila, PH' },
{ lat: 37.5665, lng: 126.9780, name: 'Seoul, KR' },
{ lat: -77.8463, lng: 166.6769, name: 'McMurdo, AQ' },
];
// Initialize state from URL parameters
const getInitialState = () => {
const params = new URLSearchParams(window.location.search);
const lat = params.get('lat');
const lng = params.get('lng');
const locName = params.get('name');
const urlDate = params.get('date');
const mode = params.get('mode');
const refs = params.get('refs');
const customLat = params.get('custom_lat');
const customLng = params.get('custom_lng');
const customName = params.get('custom_name');
// Parse custom comparison locations (can be multiple in future)
const customComparisons = [];
if (customLat && customLng) {
customComparisons.push({
lat: parseFloat(customLat),
lng: parseFloat(customLng),
name: customName || `Custom (${parseFloat(customLat).toFixed(2)}°, ${parseFloat(customLng).toFixed(2)}°)`
});
}
// Get local date in YYYY-MM-DD format
const getLocalDateString = () => {
const now = new Date();
const year = now.getFullYear();
const month = String(now.getMonth() + 1).padStart(2, '0');
const day = String(now.getDate()).padStart(2, '0');
return `${year}-${month}-${day}`;
};
return {
location: (lat && lng) ? {
lat: parseFloat(lat),
lng: parseFloat(lng),
name: locName || `Custom (${parseFloat(lat).toFixed(2)}°, ${parseFloat(lng).toFixed(2)}°)`
} : { lat: 33.4484, lng: -112.0740, name: 'Phoenix, US' },
date: urlDate || getLocalDateString(),
viewMode: mode || 'sunrise',
referenceLocations: refs ? refs.split(';') : [],
customRefLocations: customComparisons
};
};
const initial = getInitialState();
const [location, setLocation] = useState(initial.location);
const [date, setDate] = useState(initial.date);
const [viewMode, setViewMode] = useState(initial.viewMode);
const [solarData, setSolarData] = useState(null);
const [matchingPoints, setMatchingPoints] = useState([]);
const [manualLat, setManualLat] = useState('');
const [manualLng, setManualLng] = useState('');
const [manualName, setManualName] = useState('');
// Auto-detect if location is custom (not in presets) and show Coordinates tab
const locationIsPreset = presetLocations.some(p => p.name === initial.location.name);
const [useManualInput, setUseManualInput] = useState(!locationIsPreset);
// Pre-populate manual input fields if location is custom
useEffect(() => {
if (!locationIsPreset) {
setManualLat(location.lat.toString());
setManualLng(location.lng.toString());
setManualName(location.name.startsWith('Custom (') ? '' : location.name);
}
}, []);
const [referenceLocations, setReferenceLocations] = useState(initial.referenceLocations);
const [customRefLocations, setCustomRefLocations] = useState(initial.customRefLocations);
const [customRefLat, setCustomRefLat] = useState('');
const [customRefLng, setCustomRefLng] = useState('');
const [customRefName, setCustomRefName] = useState('');
const [hoveredPoint, setHoveredPoint] = useState(null);
const [clickedPoint, setClickedPoint] = useState(null);
const [showShareToast, setShowShareToast] = useState(false);
const [currentTime, setCurrentTime] = useState(new Date());
// Update current time every second
useEffect(() => {
const timer = setInterval(() => {
setCurrentTime(new Date());
}, 1000);
return () => clearInterval(timer);
}, []);
// Update URL when state changes
useEffect(() => {
const params = new URLSearchParams();
params.set('lat', location.lat.toString());
params.set('lng', location.lng.toString());
params.set('name', location.name);
params.set('date', date);
params.set('mode', viewMode);
if (referenceLocations.length > 0) {
params.set('refs', referenceLocations.join(';'));
}
// For now, save first custom location to URL (backwards compatible)
if (customRefLocations.length > 0) {
params.set('custom_lat', customRefLocations[0].lat);
params.set('custom_lng', customRefLocations[0].lng);
if (customRefLocations[0].name) {
params.set('custom_name', customRefLocations[0].name);
}
}
const newUrl = `${window.location.pathname}?${params.toString()}`;
window.history.replaceState({}, '', newUrl);
}, [location, date, viewMode, referenceLocations, customRefLocations]);
// NOAA Solar Calculations - Accurate algorithm
const calculateSunriseSunset = (lat, lng, dateStr) => {
// UTC-centric: all locations calculate for the same UTC calendar day
const date = new Date(dateStr + 'T00:00:00Z');
const year = date.getUTCFullYear();
const month = date.getUTCMonth() + 1; // 1-12
const day = date.getUTCDate();
// Calculate Julian Day - standard astronomical formula
let y = year;
let m = month;
if (m <= 2) {
y = y - 1;
m = m + 12;
}
const a = Math.floor(y / 100);
const b = 2 - a + Math.floor(a / 4);
const jd = Math.floor(365.25 * (y + 4716)) + Math.floor(30.6001 * (m + 1)) + day + b - 1524.5;
const jdn = jd - 2451545.0;
// Calculate equation of time and declination
const g = 357.529 + 0.98560028 * jdn;
const q = 280.459 + 0.98564736 * jdn;
const L = q + 1.915 * Math.sin(g * Math.PI / 180) + 0.020 * Math.sin(2 * g * Math.PI / 180);
const e = 23.439 - 0.00000036 * jdn;
let ra = Math.atan2(Math.cos(e * Math.PI / 180) * Math.sin(L * Math.PI / 180), Math.cos(L * Math.PI / 180)) * 180 / Math.PI;
// Normalize RA to same quadrant as L
const lQuad = Math.floor(L / 90) * 90;
const raQuad = Math.floor(ra / 90) * 90;
ra = ra + (lQuad - raQuad);
const dec = Math.asin(Math.sin(e * Math.PI / 180) * Math.sin(L * Math.PI / 180)) * 180 / Math.PI;
const eqTime = 4 * (q - ra);
// Calculate hour angle
const latRad = lat * Math.PI / 180;
const decRad = dec * Math.PI / 180;
const cosHA = (Math.sin(-0.833 * Math.PI / 180) - Math.sin(latRad) * Math.sin(decRad)) / (Math.cos(latRad) * Math.cos(decRad));
if (cosHA > 1) {
// Polar night - sun never rises
return { sunrise: null, sunset: null, solarNoon: null, declination: dec, polarNight: true };
}
if (cosHA < -1) {
// Midnight sun - sun never sets
return { sunrise: null, sunset: null, solarNoon: null, declination: dec, midnightSun: true };
}
const ha = Math.acos(cosHA) * 180 / Math.PI;
// Calculate sunrise and sunset in minutes from midnight
const solarNoonMin = 720 - 4 * lng - eqTime;
const sunriseMin = solarNoonMin - 4 * ha;
const sunsetMin = solarNoonMin + 4 * ha;
const toTimeStringWithDate = (minutes, baseDate) => {
let totalMinutes = minutes;
let dayOffset = 0;
// Normalize and track day offset
while (totalMinutes < 0) {
totalMinutes += 1440; // minutes in a day
dayOffset -= 1;
}
while (totalMinutes >= 1440) {
totalMinutes -= 1440;
dayOffset += 1;
}
const hours = Math.floor(totalMinutes / 60);
const mins = Math.floor(totalMinutes % 60);
const timeStr = `${hours.toString().padStart(2, '0')}:${mins.toString().padStart(2, '0')}`;
// Only show date if it's actually different from input date
let actualDate = null;
if (dayOffset !== 0) {
const resultDate = new Date(baseDate);
resultDate.setUTCDate(resultDate.getUTCDate() + dayOffset);
const resultDateStr = resultDate.toISOString().split('T')[0];
const baseDateStr = baseDate.toISOString().split('T')[0];
if (resultDateStr !== baseDateStr) {
actualDate = resultDateStr;
}
}
return { time: timeStr, date: actualDate, hours: totalMinutes / 60 };
};
const sunriseData = toTimeStringWithDate(sunriseMin, date);
const sunsetData = toTimeStringWithDate(sunsetMin, date);
const noonData = toTimeStringWithDate(solarNoonMin, date);
return {
sunrise: sunriseData.time,
sunriseDate: sunriseData.date,
sunset: sunsetData.time,
sunsetDate: sunsetData.date,
solarNoon: noonData.time,
declination: dec,
sunriseDecimal: sunriseData.hours,
sunsetDecimal: sunsetData.hours
};
};
const calculateSharedDaylight = (primarySolar, secondarySolar) => {
// Handle polar night (no shared daylight possible)
if (primarySolar.polarNight || secondarySolar.polarNight) {
return { hours: 0, minutes: 0, periods: [] };
}
const timeToMinutes = (timeStr, dateOffset = 0) => {
const [hours, mins] = timeStr.split(':').map(Number);
return hours * 60 + mins + (dateOffset * 1440);
};
// If primary has midnight sun, return secondary's full daylight duration
if (primarySolar.midnightSun && secondarySolar.sunrise) {
const secSunriseMin = timeToMinutes(secondarySolar.sunrise, secondarySolar.sunriseDate ? -1 : 0);
const secSunsetMin = timeToMinutes(secondarySolar.sunset, secondarySolar.sunsetDate ? 1 : 0);
const daylightMinutes = secSunsetMin - secSunriseMin;
return {
hours: Math.floor(daylightMinutes / 60),
minutes: Math.floor(daylightMinutes % 60),
periods: [[secSunriseMin, secSunsetMin]]
};
}
// If secondary has midnight sun, return primary's full daylight duration
if (secondarySolar.midnightSun && primarySolar.sunrise) {
const priSunriseMin = timeToMinutes(primarySolar.sunrise, primarySolar.sunriseDate ? -1 : 0);
const priSunsetMin = timeToMinutes(primarySolar.sunset, primarySolar.sunsetDate ? 1 : 0);
const daylightMinutes = priSunsetMin - priSunriseMin;
return {
hours: Math.floor(daylightMinutes / 60),
minutes: Math.floor(daylightMinutes % 60),
periods: [[priSunriseMin, priSunsetMin]]
};
}
// Both midnight sun
if (primarySolar.midnightSun && secondarySolar.midnightSun) {
return { hours: 24, minutes: 0, periods: [[0, 1440]] };
}
// Normal case: both have regular sunrise/sunset
if (!primarySolar.sunrise || !secondarySolar.sunrise) {
return { hours: 0, minutes: 0, periods: [] };
}
// Convert times to minutes from UTC midnight
const priSunriseMin = timeToMinutes(primarySolar.sunrise, primarySolar.sunriseDate ? -1 : 0);
const priSunsetMin = timeToMinutes(primarySolar.sunset, primarySolar.sunsetDate ? 1 : 0);
const secSunriseMin = timeToMinutes(secondarySolar.sunrise, secondarySolar.sunriseDate ? -1 : 0);
const secSunsetMin = timeToMinutes(secondarySolar.sunset, secondarySolar.sunsetDate ? 1 : 0);
// Check for overlap, including wrapping across days
// We need to check yesterday's, today's, and tomorrow's secondary daylight
let overlapMinutes = 0;
const periods = [];
for (let dayOffset = -1; dayOffset <= 1; dayOffset++) {
const secStart = secSunriseMin + (dayOffset * 1440);
const secEnd = secSunsetMin + (dayOffset * 1440);
const overlapStart = Math.max(priSunriseMin, secStart);
const overlapEnd = Math.min(priSunsetMin, secEnd);
if (overlapEnd > overlapStart) {
overlapMinutes += overlapEnd - overlapStart;
periods.push([overlapStart, overlapEnd]);
}
}
if (overlapMinutes === 0) {
return { hours: 0, minutes: 0, periods: [] };
}
return {
hours: Math.floor(overlapMinutes / 60),
minutes: Math.floor(overlapMinutes % 60),
periods
};
};
const isLand = (lat, lng) => {
const rowIndex = Math.round((87 - lat) / 4.047);
const colIndex = Math.round((lng + 180) / 3);
if (rowIndex < 0 || rowIndex >= 44 || colIndex < 0 || colIndex >= 120) {
return false;
}
return landSeaGrid[rowIndex][colIndex] === 1;
};
const findMatchingLocations = useMemo(() => {
if (!solarData) return [];
// For polar conditions, calculate solar noon from longitude
let referenceSunriseDecimal = solarData.sunriseDecimal;
let referenceSunsetDecimal = solarData.sunsetDecimal;
if (solarData.midnightSun || solarData.polarNight) {
// Calculate solar noon time in decimal hours
const lng = location.lng;
const solarNoonHour = 12 - (lng / 15);
const normalizedHour = ((solarNoonHour + 24) % 24);
referenceSunriseDecimal = normalizedHour;
referenceSunsetDecimal = normalizedHour;
}
// Skip if we still don't have reference times
if (referenceSunriseDecimal === undefined && referenceSunsetDecimal === undefined) return [];
const points = [];
for (let lat = LAT_MIN; lat <= LAT_MAX; lat += GRID_STEP) {
for (let lng = -180; lng < 180; lng += GRID_STEP) {
const data = calculateSunriseSunset(lat, lng, date);
if (!data.sunrise) continue;
let match = false;
let label = '';
if (viewMode === 'sunrise' && referenceSunriseDecimal !== undefined) {
const timeDiffSunrise = Math.abs(data.sunriseDecimal - referenceSunriseDecimal);
if (timeDiffSunrise < MATCH_THRESHOLD) {
match = true;
label = 'sunrise-simultaneous';
}
const sunsetDiff = Math.abs(data.sunsetDecimal - referenceSunriseDecimal);
const sunsetDiffWrapped = Math.min(sunsetDiff, 24 - sunsetDiff);
if (sunsetDiffWrapped < MATCH_THRESHOLD) {
match = true;
label = 'sunset-at-your-sunrise';
}
}
if (viewMode === 'sunset' && referenceSunsetDecimal !== undefined) {
const timeDiffSunset = Math.abs(data.sunsetDecimal - referenceSunsetDecimal);
if (timeDiffSunset < MATCH_THRESHOLD) {
match = true;
label = 'sunset-simultaneous';
}
const sunriseDiff = Math.abs(data.sunriseDecimal - referenceSunsetDecimal);
const sunriseDiffWrapped = Math.min(sunriseDiff, 24 - sunriseDiff);
if (sunriseDiffWrapped < MATCH_THRESHOLD) {
match = true;
label = 'sunrise-at-your-sunset';
}
}
if (match) {
points.push({ lat, lng, label });
}
}
}
return points;
}, [solarData, date, viewMode]);
useEffect(() => {
const data = calculateSunriseSunset(location.lat, location.lng, date);
setSolarData(data);
}, [location, date]);
useEffect(() => {
setMatchingPoints(findMatchingLocations);
}, [findMatchingLocations]);
// Combine all reference locations, maintaining insertion order
// Since we add with [...old, new] for presets and [new, ...old] for custom,
// we need to reverse presets to get newest-first, then interleave
// But we can't truly interleave without timestamps. Best approximation:
// Put all customs first (already newest-first), then all presets (reversed to newest-first)
const allReferenceLocations = [
...customRefLocations, // newest first (added with [new, ...old])
...referenceLocations.map(name => presetLocations.find(l => l.name === name)).filter(Boolean).reverse() // newest first
];
const mapWidth = 900;
const mapHeight = 450;
const projectPoint = (lat, lng) => {
const x = ((lng + 180) / 360) * mapWidth;
const y = ((87 - lat) / 174) * mapHeight;
return { x, y };
};
const handleManualLocationSubmit = () => {
const lat = parseFloat(manualLat);
const lng = parseFloat(manualLng);
if (isNaN(lat) || isNaN(lng) || lat < LAT_MIN || lat > LAT_MAX || lng < -180 || lng > 180) {
alert(`Please enter valid coordinates (Lat: ${LAT_MIN} to ${LAT_MAX}, Lng: -180 to 180)`);
return;
}
const name = manualName.trim() || `Custom (${lat.toFixed(2)}°, ${lng.toFixed(2)}°)`;
setLocation({ lat, lng, name });
};
const adjustDate = (days) => {
const currentDate = new Date(date + 'T12:00:00');
currentDate.setDate(currentDate.getDate() + days);
setDate(currentDate.toISOString().split('T')[0]);
};
const adjustMonth = (months) => {
const currentDate = new Date(date + 'T12:00:00');
currentDate.setMonth(currentDate.getMonth() + months);
setDate(currentDate.toISOString().split('T')[0]);
};
const resetToToday = () => {
const today = new Date();
const year = today.getFullYear();
const month = (today.getMonth() + 1).toString().padStart(2, '0');
const day = today.getDate().toString().padStart(2, '0');
setDate(`${year}-${month}-${day}`);
};
const handleShareClick = () => {
const url = window.location.href;
navigator.clipboard.writeText(url).then(() => {
setShowShareToast(true);
setTimeout(() => setShowShareToast(false), 2000);
});
};
const today = new Date();
const todayStr = `${today.getFullYear()}-${(today.getMonth() + 1).toString().padStart(2, '0')}-${today.getDate().toString().padStart(2, '0')}`;
const isToday = date === todayStr;
// Calculate solar data for reference locations
const referenceLocationsData = useMemo(() => {
return allReferenceLocations
.filter(loc => loc.name !== location.name)
.map(loc => {
const solar = calculateSunriseSunset(loc.lat, loc.lng, date);
const shared = solarData ? calculateSharedDaylight(solarData, solar) : null;
const isCustom = customRefLocations.some(custom =>
custom.lat === loc.lat && custom.lng === loc.lng
);
const isPreset = presetLocations.some(preset => preset.name === loc.name);
return {
...loc,
solar,
shared,
isCustom,
isPreset
};
});
}, [allReferenceLocations, location.name, date, solarData, customRefLocations]);
return (
<div className="w-full max-w-7xl mx-auto p-3 bg-zinc-900 text-white min-h-screen">
<div className="mb-4 flex items-start justify-between">
<div>
<h1 className="text-4xl font-bold mb-2 text-stone-300">
Shared Sunlight
</h1>
<p className="text-stone-300 text-base max-w-3xl mt-3">
This tool calculates sunrise and sunset times using NOAA's solar position algorithm, then displays where on Earth these transitions are happening simultaneously. The map uses an equirectangular projection at 3° resolution, meaning that each dot represents roughly 330km × 330km at the equator.
</p>
<p className="text-stone-300 text-base max-w-3xl mt-3">
All times are displayed in UTC. The selected date represents a UTC calendar day - locations in the Western Hemisphere (west of Greenwich) should subtract one day to see their local calendar date. Your local time is currently {currentTime.toLocaleTimeString('en-US', { hour: 'numeric', minute: '2-digit', timeZoneName: 'short' })}, {Math.abs(currentTime.getTimezoneOffset() / 60)} hours {currentTime.getTimezoneOffset() > 0 ? 'behind' : 'ahead of'} UTC.
</p>
</div>
<div className="flex gap-2">
<a
href="https://github.com/GrifP/shared-sunlight"
target="_blank"
rel="noopener noreferrer"
className="flex items-center justify-center bg-zinc-800 hover:bg-zinc-700 text-white p-2 rounded"
title="View on GitHub"
>
<svg width="20" height="20" fill="currentColor" viewBox="0 0 16 16">
<path d="M8 0C3.58 0 0 3.58 0 8c0 3.54 2.29 6.53 5.47 7.59.4.07.55-.17.55-.38 0-.19-.01-.82-.01-1.49-2.01.37-2.53-.49-2.69-.94-.09-.23-.48-.94-.82-1.13-.28-.15-.68-.52-.01-.53.63-.01 1.08.58 1.23.82.72 1.21 1.87.87 2.33.66.07-.52.28-.87.51-1.07-1.78-.2-3.64-.89-3.64-3.95 0-.87.31-1.59.82-2.15-.08-.2-.36-1.02.08-2.12 0 0 .67-.21 2.2.82.64-.18 1.32-.27 2-.27.68 0 1.36.09 2 .27 1.53-1.04 2.2-.82 2.2-.82.44 1.1.16 1.92.08 2.12.51.56.82 1.27.82 2.15 0 3.07-1.87 3.75-3.65 3.95.29.25.54.73.54 1.48 0 1.07-.01 1.93-.01 2.2 0 .21.15.46.55.38A8.012 8.012 0 0 0 16 8c0-4.42-3.58-8-8-8z"/>
</svg>
</a>
<button
onClick={handleShareClick}
className="flex items-center gap-2 bg-indigo-600 hover:bg-indigo-700 text-white px-3 py-2 rounded text-sm font-medium"
>
<Share size={16} />
Share
</button>
</div>
</div>
{showShareToast && (
<div className="fixed top-4 right-4 bg-indigo-600 text-white px-4 py-2 rounded shadow-lg z-50 font-medium">
Link copied to clipboard!
</div>
)}
<div className="grid grid-cols-1 md:grid-cols-2 gap-4 mb-4">
{/* Primary Location */}
<div className="bg-zinc-900 border border-zinc-700 rounded-lg p-4">
<div>
<label className="block text-base font-bold mb-2 text-stone-300">Primary Location</label>
<div className="flex gap-2 mb-2">
<button
onClick={() => setUseManualInput(false)}
className={`px-2 py-1 text-xs rounded border ${!useManualInput ? 'bg-indigo-600 text-white border-indigo-600' : 'bg-zinc-900 border-zinc-700'}`}
>
List
</button>
<button
onClick={() => setUseManualInput(true)}
className={`px-2 py-1 text-xs rounded border ${useManualInput ? 'bg-indigo-600 text-white border-indigo-600' : 'bg-zinc-900 border-zinc-700'}`}
>
Coordinates
</button>
</div>
{!useManualInput ? (
<select
value={location.name}
onChange={(e) => {
const loc = presetLocations.find(l => l.name === e.target.value);
if (loc) setLocation(loc);
}}
className="w-full bg-zinc-900 border border-zinc-700 rounded px-2 py-1 text-sm"
>
{presetLocations.map(loc => (
<option key={loc.name} value={loc.name}>{loc.name}</option>
))}
</select>
) : (
<div className="space-y-1">
<input
type="text"
placeholder="Location name (optional)"
value={manualName}
onChange={(e) => setManualName(e.target.value)}
className="w-full bg-zinc-900 border border-zinc-700 rounded px-2 py-1 text-xs"
/>
<input
type="number"
placeholder="Latitude"
value={manualLat}
onChange={(e) => setManualLat(e.target.value)}
className="w-full bg-zinc-900 border border-zinc-700 rounded px-2 py-1 text-xs"
step="0.0001"
min="-87"
max="87"
/>
<input
type="number"
placeholder="Longitude"
value={manualLng}
onChange={(e) => setManualLng(e.target.value)}
className="w-full bg-zinc-900 border border-zinc-700 rounded px-2 py-1 text-xs"
step="0.0001"
min="-180"
max="180"
/>
<button
onClick={handleManualLocationSubmit}
className="w-full bg-indigo-600 hover:bg-indigo-700 text-white px-2 py-1 rounded text-xs"
>
Set
</button>
</div>
)}
<div className="text-xs text-stone-400 mt-2">
{location.lat.toFixed(2)}°, {location.lng.toFixed(2)}°
</div>
{solarData && solarData.sunrise && (
<div className="text-sm text-stone-300 mt-2 space-y-1 font-medium">
<div className="flex items-center gap-1">
<Sun size={14} className="text-cyan-400" />
<span>{solarData.sunrise} UTC</span>
{solarData.sunriseDate && (
<span className="text-stone-400 text-xs">
({new Date(solarData.sunriseDate + 'T12:00:00').toLocaleDateString('en-US', { month: 'short', day: 'numeric' })})
</span>
)}
</div>
<div className="flex items-center gap-1">
<Moon size={14} className="text-pink-500" />
<span>{solarData.sunset} UTC</span>
{solarData.sunsetDate && (
<span className="text-stone-400 text-xs">
({new Date(solarData.sunsetDate + 'T12:00:00').toLocaleDateString('en-US', { month: 'short', day: 'numeric' })})
</span>
)}
</div>
<div className="flex items-center gap-1">
<Clock size={14} className="text-yellow-400" />
<span>{(() => {
let sunriseMin = parseInt(solarData.sunrise.split(':')[0]) * 60 + parseInt(solarData.sunrise.split(':')[1]);
let sunsetMin = parseInt(solarData.sunset.split(':')[0]) * 60 + parseInt(solarData.sunset.split(':')[1]);
// Adjust for date offsets
if (solarData.sunriseDate) sunriseMin -= 1440;
if (solarData.sunsetDate) sunsetMin += 1440;
const daylightMin = sunsetMin - sunriseMin;
const hours = Math.floor(daylightMin / 60);
const mins = daylightMin % 60;
return `${hours}h ${mins}m daylight`;
})()}</span>
</div>
</div>
)}
{solarData && !solarData.sunrise && (
<div className="text-sm text-stone-300 mt-2 font-medium">
<div className="flex items-center gap-1">
{solarData.midnightSun ? (
<>
<Sun size={14} className="text-cyan-400" />
<span>Midnight sun</span>
</>
) : solarData.polarNight ? (
<>
<Moon size={14} className="text-pink-500" />
<span>Polar night</span>
</>
) : (
<span>No sunrise/sunset</span>
)}
</div>
</div>
)}
</div>
</div>
{/* Date */}
<div className="bg-zinc-900 border border-zinc-700 rounded-lg p-4">
<div>
<label className="block text-base font-bold mb-2 text-stone-300">UTC Day</label>
<div className="flex items-center gap-1 mb-2">
<button
onClick={() => adjustDate(-1)}
className="bg-zinc-900 hover:bg-indigo-900 p-1 rounded"
>
<ChevronLeft size={14} />
</button>
<input
type="date"
value={date}
onChange={(e) => setDate(e.target.value)}
className="flex-1 bg-zinc-900 border border-zinc-700 rounded px-2 py-1 text-xs"
/>
<button
onClick={() => adjustDate(1)}
className="bg-zinc-900 hover:bg-indigo-900 p-1 rounded"
>
<ChevronRight size={14} />
</button>
</div>
<p className="text-stone-400 text-xs mb-2">
Western Hemisphere: subtract 1 day for local date
</p>
<div className="flex gap-1 mb-2">
<button
onClick={() => adjustMonth(-1)}
className="flex-1 bg-zinc-900 hover:bg-indigo-900 px-2 py-1 rounded text-xs border border-zinc-700"
>
← Month
</button>
<button
onClick={resetToToday}
disabled={isToday}
className={`flex-1 px-2 py-1 rounded text-xs border ${isToday ? 'bg-zinc-900 opacity-50 cursor-not-allowed border-zinc-700' : 'bg-indigo-600 hover:bg-indigo-700 text-white border-indigo-600'}`}
>
Today
</button>
<button
onClick={() => adjustMonth(1)}
className="flex-1 bg-zinc-900 hover:bg-indigo-900 px-2 py-1 rounded text-xs border border-zinc-700"
>
Month →
</button>
</div>
</div>
</div>
</div>
<div className="grid grid-cols-1 lg:grid-cols-4 gap-4 mb-4">
<div className="lg:col-span-3">
<div className="bg-zinc-900 border border-zinc-700 rounded-lg p-4">
<div className="mb-3">
<h3 className="text-base font-bold text-stone-300 mb-1">Shared Daylight with {location.name}</h3>
{(() => {
const activeLocations = referenceLocationsData.filter(loc =>
referenceLocations.includes(loc.name) ||
customRefLocations.some(c => c.lat === loc.lat && c.lng === loc.lng)
);
if (activeLocations.length === 0) {
return (
<div className="text-sm text-stone-400">
Select a comparison location to see shared sunlight
</div>
);
}
// Calculate intersection
let intersectedPeriods = activeLocations[0].shared?.periods || [];
if (!intersectedPeriods || intersectedPeriods.length === 0) {
return (
<div className="text-sm text-stone-400">
No shared sunlight between {activeLocations.length + 1} locations
</div>
);
}
for (let i = 1; i < activeLocations.length; i++) {
const locPeriods = activeLocations[i].shared?.periods || [];
if (locPeriods.length === 0) {
return (
<div className="text-sm text-stone-400">
No shared sunlight between {activeLocations.length + 1} locations
</div>
);
}
const newPeriods = [];
for (const [aStart, aEnd] of intersectedPeriods) {
for (const [bStart, bEnd] of locPeriods) {
const overlapStart = Math.max(aStart, bStart);
const overlapEnd = Math.min(aEnd, bEnd);
if (overlapEnd > overlapStart) {
newPeriods.push([overlapStart, overlapEnd]);
}
}
}
intersectedPeriods = newPeriods;
if (intersectedPeriods.length === 0) {
return (
<div className="text-sm text-stone-400">
No shared sunlight between {activeLocations.length + 1} locations
</div>
);
}
}
const totalMinutes = intersectedPeriods.reduce((sum, [start, end]) => sum + (end - start), 0);
if (totalMinutes <= 0) {
return (
<div className="text-sm text-stone-400">
No shared sunlight between {activeLocations.length + 1} locations
</div>
);
}
const hours = Math.floor(totalMinutes / 60);
const mins = Math.floor(totalMinutes % 60);
return (
<div className="text-sm text-stone-300">
<span className="text-yellow-400 font-semibold">{hours}h {mins}m</span> of shared sunlight between {activeLocations.length + 1} locations
</div>
);
})()}
</div>
<div className="flex gap-2 mb-3">
<button
onClick={() => setViewMode('sunrise')}
className={`px-4 py-1 rounded text-xs border ${viewMode === 'sunrise' ? 'bg-indigo-600 text-white border-indigo-600' : 'bg-zinc-900 hover:bg-indigo-900 border-zinc-700'}`}
>
At My Sunrise
</button>
<button
onClick={() => setViewMode('sunset')}
className={`px-4 py-1 rounded text-xs border ${viewMode === 'sunset' ? 'bg-indigo-600 text-white border-indigo-600' : 'bg-zinc-900 hover:bg-indigo-900 border-zinc-700'}`}
>
At My Sunset
</button>
</div>
<div className="relative bg-zinc-900 rounded overflow-hidden border border-zinc-700">
<svg
width={mapWidth}
height={mapHeight}
viewBox={`0 0 ${mapWidth} ${mapHeight}`}
className="w-full h-auto"
onMouseMove={(e) => {
const rect = e.currentTarget.getBoundingClientRect();
const x = e.clientX - rect.left;
const y = e.clientY - rect.top;
const scaleX = mapWidth / rect.width;
const scaleY = mapHeight / rect.height;
const svgX = x * scaleX;
const svgY = y * scaleY;
const lng = (svgX / mapWidth) * 360 - 180;
const lat = 87 - (svgY / mapHeight) * 174;
const snapLat = Math.round(lat / 3) * 3;
const snapLng = Math.round(lng / 3) * 3;
if (snapLat >= -87 && snapLat <= 87 && snapLng >= -180 && snapLng < 180) {
setHoveredPoint({ lat: snapLat, lng: snapLng });
}
}}
onMouseLeave={() => setHoveredPoint(null)}
onClick={(e) => {
const rect = e.currentTarget.getBoundingClientRect();
const x = e.clientX - rect.left;
const y = e.clientY - rect.top;
const scaleX = mapWidth / rect.width;
const scaleY = mapHeight / rect.height;
const svgX = x * scaleX;
const svgY = y * scaleY;
const lng = (svgX / mapWidth) * 360 - 180;
const lat = 87 - (svgY / mapHeight) * 174;
const snapLat = Math.round(lat / 3) * 3;
const snapLng = Math.round(lng / 3) * 3;
if (snapLat >= -87 && snapLat <= 87 && snapLng >= -180 && snapLng < 180) {
setClickedPoint({ lat: snapLat, lng: snapLng });
}
}}
>
<rect width={mapWidth} height={mapHeight} fill="#18181b" />
{[-60, -30, 0, 30, 60].map(lat => {