248 lines
16 KiB
JavaScript
248 lines
16 KiB
JavaScript
// ════════════════════════════════════════════════════════════════════════
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// utils.js — Pure helper functions and lookup tables.
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//
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// Exports:
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// utciCategory(u) UTCI stress band → {label,bg,fg}
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// precipPenalty(precipMm,snowCmH,windMs) SunScope soak-factor
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// windCompass8(deg) bearing → {label, snapped}
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// uvSplit(uv, elevDeg) total UV → {uvA, uvB}
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// SKIN_TYPES Fitzpatrick skin type table
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// sunburnMinutes(uv, skinType) minutes to MED
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// burnLabel(mins) formats burn time as "12m"/"1.5h"
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// cloudCategory(total,low,mid,high) → 'clear'|'wispy'|'scattered'|'overcast'
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// confidenceBand(i) day-tab gradient + label
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// moonPhaseFraction(date) 0..1 synodic phase
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// moonGlyph(p) phase fraction → emoji
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// skyFillForElev(e) solar elevation → sky hex colour
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// grassFillForElev(e) solar elevation → {top,bot} hex
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// ════════════════════════════════════════════════════════════════════════
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// ═══════════════════════════════════════════════════════════════════
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// UTCI THERMAL STRESS BANDS — the coloured pills in the table.
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// ───────────────────────────────────────────────────────────────────
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// To recolour any band, change its bg/fg hex code. To shift the
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// boundary between bands (e.g. make "Comfortable" wider), change the
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// `if (u < …)` thresholds. Order matters — they're checked top-down.
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// ═══════════════════════════════════════════════════════════════════
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export function utciCategory(u) {
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if (u < -40) return { label: 'Extreme cold', bg: '#1a1438', fg: '#fff' };
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if (u < -27) return { label: 'Very strong cold', bg: '#23408f', fg: '#fff' };
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if (u < -13) return { label: 'Arctic', bg: '#3f73c4', fg: '#fff' };
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if (u < 0) return { label: 'Freezing', bg: '#7eb0e0', fg: '#1a1612' };
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if (u < 9) return { label: 'Cold', bg: '#bcd9ec', fg: '#1a1612' };
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if (u < 18) return { label: 'Chilled', bg: '#c8dcc0', fg: '#1a1612' };
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if (u < 26) return { label: 'Comfortable', bg: '#6ab05a', fg: '#fff' };
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if (u < 32) return { label: 'Moderate heat', bg: '#e8c547', fg: '#1a1612' };
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if (u < 38) return { label: 'Strong heat', bg: '#dc8a3a', fg: '#1a1612' };
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if (u < 46) return { label: 'Very strong heat', bg: '#c44a3a', fg: '#fff' };
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return { label: 'Extreme heat', bg: '#7a1a1a', fg: '#fff' };
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}
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// ═══════════════════════════════════════════════════════════════════
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// SOAK-FACTOR — SunScope's original rain/snow penalty.
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// ───────────────────────────────────────────────────────────────────
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// This is what makes "UTCI+P" different from plain UTCI. It subtracts
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// extra felt-temperature for rain (wet clothing = evaporative chill)
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// and snow (wet snow is brutal). Wind amplifies the rain penalty.
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// Calibrated by feel — adjust the multipliers if you find it too
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// strong/weak. The big number "7" caps the max rain penalty so a
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// freak 50mm/h reading can't make UTCI nonsensical.
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// ═══════════════════════════════════════════════════════════════════
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export function precipPenalty(precipMm, snowCmH, windMs) {
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let penalty = 0;
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if (precipMm > 0) {
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const base = Math.min(7, 1.4 * Math.pow(precipMm, 0.55) + precipMm * 0.28);
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const windMult = 1 + Math.min(0.35, windMs * 0.025);
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penalty += base * windMult;
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}
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if (snowCmH > 0) penalty += Math.min(6, 2.2 + snowCmH * 1.6);
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return -Math.round(penalty * 10) / 10;
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}
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// ═══════════════════════════════════════════════════════════════════
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// WIND COMPASS — meteorological bearing (deg FROM) → 8-point label.
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// ───────────────────────────────────────────────────────────────────
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// 0/360 = wind FROM north. The pointer in WindVane should rotate so
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// the arrow's tail points to this bearing (i.e. shows where the wind
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// comes from), matching how real weather vanes behave.
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// ═══════════════════════════════════════════════════════════════════
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export function windCompass8(deg) {
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if (deg == null || isNaN(deg)) return { label: '—', snapped: 0 };
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const dirs = ['N','NE','E','SE','S','SW','W','NW'];
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const idx = Math.round(((deg % 360) + 360) % 360 / 45) % 8;
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return { label: dirs[idx], snapped: idx * 45 };
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}
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// ═══════════════════════════════════════════════════════════════════
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// UV-A / UV-B SPLIT (estimate, not measurement).
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// ───────────────────────────────────────────────────────────────────
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// Open-Meteo gives a total erythemal UV index. UV-A reaches the
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// surface much more reliably than UV-B; UV-B is far more sensitive
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// to solar elevation because of atmospheric path length.
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//
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// Cheap model:
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// At noon (sun overhead) the UV-B share of total UV index is ~15%,
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// UV-A about 85%. Below ~10° solar elevation, UV-B falls off fast.
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// We return two pseudo-"index" numbers so the columns are in the
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// same units the user already understands.
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// Label these as estimates in the UI.
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// ═══════════════════════════════════════════════════════════════════
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export function uvSplit(uv, elevDeg) {
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if (!uv || uv <= 0 || elevDeg <= 0) return { uvA: 0, uvB: 0 };
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const sinE = Math.sin(elevDeg * Math.PI / 180);
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const uvbFr = Math.max(0.005, Math.min(0.15, 0.15 * Math.pow(sinE, 1.6)));
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const uvaFr = 1 - uvbFr;
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return { uvA: uv * uvaFr, uvB: uv * uvbFr };
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}
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// ═══════════════════════════════════════════════════════════════════
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// SUNBURN TIME — minutes to MED for the chosen Fitzpatrick skin type.
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// ───────────────────────────────────────────────────────────────────
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// Standard erythemal model: time_min ≈ base_minutes[type] / UV_index.
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// Numbers are the well-known "unprotected, midday, no sunscreen"
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// reference times at UV = 1. Returns Infinity when UV is 0 (night).
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// ═══════════════════════════════════════════════════════════════════
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export const SKIN_TYPES = {
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I: { name: 'I · Very fair', base: 67 },
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II: { name: 'II · Fair', base: 100 },
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III: { name: 'III · Light', base: 200 },
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IV: { name: 'IV · Mid', base: 300 },
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V: { name: 'V · Dark', base: 400 },
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VI: { name: 'VI · Very dark', base: 500 },
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};
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export function sunburnMinutes(uv, skinType = 'II') {
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if (!uv || uv <= 0) return Infinity;
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const base = (SKIN_TYPES[skinType] || SKIN_TYPES.II).base;
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return base / uv;
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}
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export function burnLabel(mins) {
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if (!isFinite(mins)) return '—';
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if (mins >= 480) return '8h+';
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if (mins >= 60) return `${(mins/60).toFixed(1)}h`;
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return `${Math.round(mins)}m`;
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}
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// ═══════════════════════════════════════════════════════════════════
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// CLOUD CATEGORY — pick one of 4 icon styles from low/mid/high split.
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// ───────────────────────────────────────────────────────────────────
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// Returns: 'clear' | 'wispy' | 'scattered' | 'overcast'
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// Uses total cover for headline level, but biases towards 'wispy'
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// when only high cloud is present (cirrus barely blocks the sun).
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// ═══════════════════════════════════════════════════════════════════
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export function cloudCategory(total, low, mid, high) {
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const t = total ?? 0;
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const l = low ?? 0;
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const m = mid ?? 0;
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const h = high ?? 0;
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if (t < 10) return 'clear';
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// Mostly high cloud with little low/mid → wispy regardless of % total
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if (h > 40 && l < 25 && m < 25) return 'wispy';
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if (t < 40) return 'wispy';
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if (t < 75) return 'scattered';
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return 'overcast';
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}
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// ═══════════════════════════════════════════════════════════════════
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// CONFIDENCE BANDS — smooth high-noon → sunset gradient on day tabs.
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// ───────────────────────────────────────────────────────────────────
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// `i` is the day index (0 = today, 13 = day 14).
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//
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// Each day gets its own shade, interpolated between two endpoint
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// colours. To re-skin the gradient (say, blue-to-purple instead of
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// sunset), just change the four RGB endpoint arrays below.
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//
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// bg = tab background (lighter on day 0, darker on day 13)
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// edge = active-tab underline + slim border on the banner
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// tint = soft wash on the confidence banner above the table
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// label = qualitative zone name shown in the banner ("Golden hour")
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//
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// The label switches in 4 stages so users still see a friendly
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// description ("you're in the trustworthy zone" vs "this is an
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// outlook"). The tab background itself flows smoothly day to day.
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// ═══════════════════════════════════════════════════════════════════
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export function confidenceBand(i) {
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// Position along the gradient: 0 on day 0, 1 on day 13.
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const t = Math.min(1, Math.max(0, i / 13));
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// ENDPOINTS — change these four RGB arrays to re-skin the gradient.
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const bgStart = [255, 247, 214]; // #fff7d6 pale yellow (high noon)
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const bgEnd = [232, 152, 104]; // #e89868 terracotta (sunset)
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const edgeStart = [245, 231, 161]; // #f5e7a1 soft golden
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const edgeEnd = [196, 115, 64]; // #c47340 burnt umber
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// Linear interpolation between the two endpoints.
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const lerp = (a, b) => Math.round(a + t * (b - a));
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const mix = (s, e) => [lerp(s[0], e[0]), lerp(s[1], e[1]), lerp(s[2], e[2])];
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const [br, bg, bb] = mix(bgStart, bgEnd);
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const [er, eg, eb] = mix(edgeStart, edgeEnd);
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return {
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bg: `rgb(${br}, ${bg}, ${bb})`,
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edge: `rgb(${er}, ${eg}, ${eb})`,
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tint: `rgba(${er}, ${eg}, ${eb}, 0.22)`,
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// Qualitative confidence label (camera-focus metaphor —
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// on-brand for SunScope, and instantly readable).
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label: i < 3 ? 'Pin-sharp' // days 1–3 highest skill
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: i < 7 ? 'Sharp' // days 4–7 solid
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: i < 10 ? 'Soft focus' // days 8–10 trends only
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: 'Blurry', // days 11–14 outlook only
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};
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}
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// ═══════════════════════════════════════════════════════════════════
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// MOON PHASE — works out which moon emoji to show on night hours.
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// ───────────────────────────────────────────────────────────────────
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// Returns a fraction 0..1:
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// 0.00 = new moon 0.50 = full moon
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// 0.25 = first quarter 0.75 = last quarter
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// The maths is a simple synodic-period calculation referenced from
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// a known new moon (6 Jan 2000). Accurate to within a few hours.
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// ═══════════════════════════════════════════════════════════════════
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export function moonPhaseFraction(date) {
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const JD = date.getTime() / 86400000 + 2440587.5;
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const syn = 29.530588;
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const ref = 2451550.1;
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let p = ((JD - ref) % syn) / syn;
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if (p < 0) p += 1;
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return p;
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}
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export function moonGlyph(p) {
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return ['🌑','🌒','🌓','🌔','🌕','🌖','🌗','🌘'][Math.floor(p*8 + 0.5) % 8];
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}
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// ═══════════════════════════════════════════════════════════════════
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// SKY FILL — colour inside the little circle, based on sun elevation.
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// ───────────────────────────────────────────────────────────────────
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// > 30° high noon (bright blue)
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// > 10° mid-sky (pale blue)
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// > 3° morning/afternoon (warm gold)
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// > -3° golden hour / sunset (deep amber)
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// > -8° civil twilight (dusky lilac)
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// > -14° nautical twilight (deep blue-violet)
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// else night (indigo)
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// To shift "when sunset starts" visually, tweak the elevation
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// thresholds. To recolour: replace the hex codes.
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// ═══════════════════════════════════════════════════════════════════
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export function skyFillForElev(e) {
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if (e > 30) return '#9fd3ef';
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if (e > 10) return '#c8e3ee';
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if (e > 3) return '#ffd596';
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if (e > -3) return '#f59b6e';
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if (e > -8) return '#9279b0';
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if (e > -14) return '#3a2f60';
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return '#1a1538';
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}
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// Grass palette — mirrors skyFillForElev but for the ground.
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// `top` = grass blade tips (catches sky light), `bot` = soil shadow.
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export function grassFillForElev(e) {
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if (e > 30) return { top: '#86c44a', bot: '#558a2e' }; // bright noon grass
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if (e > 10) return { top: '#7ab846', bot: '#4d802c' }; // mid-day
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if (e > 3) return { top: '#b8a83e', bot: '#7a6a26' }; // golden-hour glow
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if (e > -3) return { top: '#c08048', bot: '#7a4a2a' }; // sunrise/sunset embers
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if (e > -8) return { top: '#665884', bot: '#3e3556' }; // civil twilight purple
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if (e > -14) return { top: '#363356', bot: '#1c1a34' }; // nautical night
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return { top: '#201d3a', bot: '#0d0b20' }; // astronomical night
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}
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