perfect-postcode/frontend/src/components/home/ScrollStory.tsx

439 lines
17 KiB
TypeScript

import { useState, useEffect, useRef, useMemo, useDeferredValue } from 'react';
import MapComponent from '../map/Map';
import { apiUrl, assertOk, authHeaders, logNonAbortError } from '../../lib/api';
import { formatValue } from '../../lib/format';
import { zoomToResolution } from '../../lib/map-utils';
import { FEATURE_GRADIENT } from '../../lib/consts';
import { gradientToCss } from '../../lib/utils';
import { SpinnerIcon } from '../ui/icons/SpinnerIcon';
import type { FeatureMeta, HexagonData } from '../../types';
const DEMO_VIEW_START = { longitude: -0.12, latitude: 51.51, zoom: 5.5, pitch: 0 };
const DEMO_VIEW_END = { longitude: -0.12, latitude: 51.51, zoom: 7, pitch: 0 };
function easeOutCubic(t: number): number {
return 1 - Math.pow(1 - t, 3);
}
const DEMO_FEATURE_NAMES = [
'Estimated current price',
'Good+ primary schools within 5km',
'Number of restaurants within 2km',
];
const noop = () => { };
// Filter fractions per stage: featureName -> [minFrac, maxFrac]
// 0 = feature.min, 1 = feature.max
interface StageDef {
filters: Record<string, [number, number]>;
colorFeature?: string;
}
const STAGES: StageDef[] = [
// 0: No filters — the problem
{ filters: {}, colorFeature: 'Estimated current price' },
// 1: Price filter — "affordable price"
{
filters: { 'Estimated current price': [0, 0.25] },
colorFeature: 'Estimated current price',
},
// 2: Price + schools
{
filters: {
'Estimated current price': [0, 0.25],
'Good+ primary schools within 5km': [0.3, 1],
},
colorFeature: 'Good+ primary schools within 5km',
},
// 3: All three
{
filters: {
'Estimated current price': [0, 0.25],
'Good+ primary schools within 5km': [0.3, 1],
'Number of restaurants within 2km': [0.15, 1],
},
colorFeature: 'Number of restaurants within 2km',
},
// 4: Same filters — "that's just three"
{
filters: {
'Estimated current price': [0, 0.25],
'Good+ primary schools within 5km': [0.3, 1],
'Number of restaurants within 2km': [0.15, 1],
},
colorFeature: 'Number of restaurants within 2km',
},
];
const STEPS: { heading: string | null; body: React.ReactNode }[] = [
{
heading: null,
body: (
<>
<p className="text-lg leading-relaxed mb-4">
Let&apos;s look at an example:
</p>
<p className="text-lg leading-relaxed mb-4">
You&apos;re about to spend{' '}
<strong className="text-navy-950 dark:text-warm-100">
&pound;300k&ndash;&pound;400k
</strong>{' '}
on a home, somewhere commutable to work in, say, London. Your research method? Picking some areas you think are good based on word of mouth... then hope for the best.
</p>
</>
),
},
{
heading: null,
body: (
<>
<div className="flex items-center gap-3 mb-3">
<div className="shrink-0 w-8 h-8 rounded-full bg-teal-600 text-white flex items-center justify-center font-bold text-sm">
1
</div>
<h3 className="text-xl font-bold text-navy-950 dark:text-warm-100">Set your must-haves</h3>
</div>
<p className="text-lg leading-relaxed">
Say you want a home at an{' '}
<strong className="text-navy-950 dark:text-warm-100">affordable price</strong>&hellip;
</p>
</>
),
},
{
heading: null,
body: (
<p className="text-lg leading-relaxed">
&hellip;with{' '}
<strong className="text-navy-950 dark:text-warm-100">good primary schools</strong>{' '}
nearby&hellip;
</p>
),
},
{
heading: null,
body: (
<p className="text-lg leading-relaxed">
&hellip;and{' '}
<strong className="text-navy-950 dark:text-warm-100">
restaurants within walking distance
</strong>
.
</p>
),
},
{
heading: null,
body: (
<>
<p className="text-lg leading-relaxed mb-4 font-semibold text-navy-950 dark:text-warm-100">
No area chosen. No listings browsed. Yet you already know exactly where your needs are met.
</p>
<p className="text-lg leading-relaxed">
That&apos;s just 3 filters. We&apos;ve built <strong className="text-navy-950 dark:text-warm-100">56</strong> &mdash;
covering commute times, crime, broadband, noise, schools, amenities, and more.
</p>
</>
),
},
];
interface ScrollStoryProps {
features: FeatureMeta[];
theme: 'light' | 'dark';
}
export default function ScrollStory({ features, theme }: ScrollStoryProps) {
const [stage, setStage] = useState(0);
const [hexData, setHexData] = useState<HexagonData[]>([]);
const [loading, setLoading] = useState(true);
const stepRefs = useRef<(HTMLDivElement | null)[]>([]);
const abortRef = useRef<AbortController>();
const fetchTimeoutRef = useRef<ReturnType<typeof setTimeout>>();
const sectionRef = useRef<HTMLElement>(null);
const [scrollProgress, setScrollProgress] = useState(0);
const rafRef = useRef<number>(0);
const demoFeatures = useMemo(
() =>
DEMO_FEATURE_NAMES.map((name) => features.find((f) => f.name === name)).filter(
Boolean
) as FeatureMeta[],
[features]
);
// Compute actual filter values from stage fractions + feature metadata
const stageFilters = useMemo(() => {
const stageDef = STAGES[stage];
const result: Record<string, [number, number]> = {};
for (const [name, [minFrac, maxFrac]] of Object.entries(stageDef.filters)) {
const meta = demoFeatures.find((f) => f.name === name);
if (meta?.min != null && meta?.max != null) {
const range = meta.max - meta.min;
result[name] = [meta.min + range * minFrac, meta.min + range * maxFrac];
}
}
return result;
}, [stage, demoFeatures]);
// IntersectionObserver for scroll stage detection
useEffect(() => {
const observers: IntersectionObserver[] = [];
stepRefs.current.forEach((el, i) => {
if (!el) return;
const observer = new IntersectionObserver(
([entry]) => {
if (entry.isIntersecting) setStage(i);
},
{ rootMargin: '-35% 0px -35% 0px', threshold: 0 }
);
observer.observe(el);
observers.push(observer);
});
return () => observers.forEach((o) => o.disconnect());
}, [demoFeatures.length]);
// Track scroll progress through the section for zoom interpolation
useEffect(() => {
const section = sectionRef.current;
if (!section) return;
let scrollParent: HTMLElement | null = section.parentElement;
while (scrollParent) {
const { overflow, overflowY } = getComputedStyle(scrollParent);
if (['auto', 'scroll'].includes(overflow) || ['auto', 'scroll'].includes(overflowY)) break;
scrollParent = scrollParent.parentElement;
}
if (!scrollParent) return;
const handleScroll = () => {
cancelAnimationFrame(rafRef.current);
rafRef.current = requestAnimationFrame(() => {
const rect = section.getBoundingClientRect();
const viewportHeight = window.innerHeight;
const totalTravel = rect.height - viewportHeight;
if (totalTravel <= 0) return;
const scrolled = -rect.top;
const progress = Math.max(0, Math.min(1, scrolled / totalTravel));
setScrollProgress(progress);
});
};
scrollParent.addEventListener('scroll', handleScroll, { passive: true });
handleScroll();
return () => {
scrollParent.removeEventListener('scroll', handleScroll);
cancelAnimationFrame(rafRef.current);
};
}, []);
const demoView = useMemo(() => {
const t = easeOutCubic(scrollProgress);
return {
longitude: DEMO_VIEW_START.longitude + (DEMO_VIEW_END.longitude - DEMO_VIEW_START.longitude) * t,
latitude: DEMO_VIEW_START.latitude + (DEMO_VIEW_END.latitude - DEMO_VIEW_START.latitude) * t,
zoom: DEMO_VIEW_START.zoom + (DEMO_VIEW_END.zoom - DEMO_VIEW_START.zoom) * t,
pitch: 0,
};
}, [scrollProgress]);
// Derive H3 resolution from current zoom (discrete — only changes at thresholds)
const resolution = zoomToResolution(demoView.zoom);
// Compute bounds string from current view, rounded to 0.5° to avoid refetching on every scroll tick
const demoBounds = useMemo(() => {
const { longitude, latitude, zoom } = demoView;
const scale = Math.pow(2, zoom);
const degreesPerPixelLng = 360 / (512 * scale);
const halfW = (1200 / 2) * degreesPerPixelLng * 1.3;
const latRad = (latitude * Math.PI) / 180;
const mercY = (1 - Math.log(Math.tan(latRad) + 1 / Math.cos(latRad)) / Math.PI) / 2;
const worldSize = 512 * scale;
const halfH = (800 / 2) * 1.3;
const topY = mercY * worldSize - halfH;
const botY = mercY * worldSize + halfH;
const toLat = (py: number) => {
const my = Math.max(0.001, Math.min(0.999, py / worldSize));
return (Math.atan(Math.sinh(Math.PI * (1 - 2 * my))) * 180) / Math.PI;
};
const snap = (v: number) => Math.round(v * 2) / 2;
const south = snap(Math.max(-85, toLat(botY)));
const west = snap(Math.max(-180, longitude - halfW));
const north = snap(Math.min(85, toLat(topY)));
const east = snap(Math.min(180, longitude + halfW));
return `${south},${west},${north},${east}`;
}, [demoView]);
// Fetch hex data when resolution, filters, or bounds change
useEffect(() => {
if (features.length === 0) return;
const params = new URLSearchParams({
resolution: String(resolution),
bounds: demoBounds,
});
const filterParts: string[] = [];
for (const [name, [min, max]] of Object.entries(stageFilters)) {
filterParts.push(`${name}:${min}:${max}`);
}
if (filterParts.length > 0) params.set('filters', filterParts.join(','));
const stageDef = STAGES[stage];
if (stageDef.colorFeature) params.set('fields', stageDef.colorFeature);
clearTimeout(fetchTimeoutRef.current);
fetchTimeoutRef.current = setTimeout(() => {
abortRef.current?.abort();
abortRef.current = new AbortController();
fetch(apiUrl('hexagons', params), authHeaders({ signal: abortRef.current.signal }))
.then((res) => {
assertOk(res, 'hexagons');
return res.json();
})
.then((data: { features: HexagonData[] }) => {
setHexData(data.features);
setLoading(false);
})
.catch((err) => logNonAbortError('Failed to fetch story hexagons', err));
}, 300);
return () => clearTimeout(fetchTimeoutRef.current);
}, [features, stageFilters, stage, resolution, demoBounds]);
useEffect(() => {
return () => {
abortRef.current?.abort();
clearTimeout(fetchTimeoutRef.current);
};
}, []);
const stageDef = STAGES[stage];
const viewFeatureName = stageDef.colorFeature || null;
const viewMeta = viewFeatureName ? features.find((f) => f.name === viewFeatureName) : null;
const colorRange: [number, number] | null =
viewMeta?.min != null && viewMeta?.max != null ? [viewMeta.min, viewMeta.max] : null;
// Defer hex data so scroll zoom stays smooth while layer rebuilds happen in the background
const deferredHexData = useDeferredValue(hexData);
return (
<section ref={sectionRef} className="snap-start relative">
{/* Sticky map background */}
<div className="sticky top-0 h-[60vh] md:h-[calc(100dvh-3rem)] z-0">
<div className="absolute inset-0">
<MapComponent
data={deferredHexData}
postcodeData={[]}
usePostcodeView={false}
pois={[]}
onViewChange={noop}
viewFeature={viewFeatureName}
colorRange={colorRange}
filterRange={null}
viewSource={viewFeatureName ? 'drag' : null}
onCancelPin={noop}
features={features}
selectedHexagonId={null}
hoveredHexagonId={null}
onHexagonClick={noop}
onHexagonHover={noop}
initialViewState={demoView}
theme={theme}
screenshotMode={true}
hideLegend={true}
/>
</div>
{/* Interaction blocker */}
<div className="absolute inset-0 z-30" />
{/* Loading */}
{loading && (
<div className="absolute inset-0 z-50 flex items-center justify-center bg-warm-50/80 dark:bg-navy-950/80 backdrop-blur-sm">
<SpinnerIcon className="w-10 h-10 text-teal-600 dark:text-teal-400 animate-spin" />
</div>
)}
{/* Filter indicators — left sidebar */}
<div className="absolute top-0 left-0 bottom-0 z-40 pointer-events-none w-[280px] md:w-[340px] flex items-center">
<div className="bg-white/85 dark:bg-warm-800/85 rounded-r-xl p-5 md:p-6 backdrop-blur-sm shadow-lg space-y-5 w-full">
<div className="text-xs font-semibold uppercase tracking-wider text-warm-500 dark:text-warm-400 mb-1">
Filters
</div>
{demoFeatures.map((feature) => {
const filterVal = stageFilters[feature.name];
const isActive = !!filterVal;
const min = feature.min ?? 0;
const max = feature.max ?? 1;
const range = max - min || 1;
const leftPct = filterVal ? ((filterVal[0] - min) / range) * 100 : 0;
const widthPct = filterVal ? ((filterVal[1] - filterVal[0]) / range) * 100 : 100;
return (
<div
key={feature.name}
className={`transition-opacity duration-700 ${isActive ? 'opacity-100' : 'opacity-30'}`}
>
<div className="flex justify-between items-baseline text-sm mb-1.5 gap-2">
<span
className={`font-medium truncate ${isActive ? 'text-navy-950 dark:text-warm-100' : 'text-warm-400 dark:text-warm-500'}`}
>
{feature.name}
</span>
{isActive && filterVal && (
<span className="text-teal-600 dark:text-teal-400 font-semibold whitespace-nowrap">
{formatValue(filterVal[0], feature)}&ndash;
{formatValue(filterVal[1], feature)}
</span>
)}
</div>
<div className="relative h-2.5 bg-warm-200 dark:bg-warm-700 rounded-full overflow-hidden">
<div
className="absolute h-full bg-teal-500 dark:bg-teal-400 rounded-full transition-all duration-700 ease-out"
style={{ left: `${leftPct}%`, width: `${widthPct}%` }}
/>
</div>
</div>
);
})}
{/* Color legend */}
{viewFeatureName && colorRange && (
<div className="pt-4 border-t border-warm-200 dark:border-warm-700 transition-opacity duration-700">
<div className="text-xs font-semibold uppercase tracking-wider text-warm-500 dark:text-warm-400 mb-2">
Colour
</div>
<div className="text-sm font-medium text-navy-950 dark:text-warm-100 mb-1.5">
{viewFeatureName}
</div>
<div className="h-2.5 rounded-full overflow-hidden" style={{ background: gradientToCss(FEATURE_GRADIENT) }} />
<div className="flex justify-between mt-1 text-xs text-warm-500 dark:text-warm-400">
<span>{formatValue(colorRange[0], viewMeta!)}</span>
<span>{formatValue(colorRange[1], viewMeta!)}</span>
</div>
</div>
)}
</div>
</div>
</div>
{/* Scrolling text overlay */}
<div className="relative z-10 -mt-[60vh] md:-mt-[calc(100dvh-3rem)] pointer-events-none">
<div className="mx-4 md:ml-auto md:mr-[4%] md:max-w-md">
<div className="h-[35vh] md:h-[45vh]" />
{STEPS.map((step, i) => (
<div
key={i}
ref={(el) => {
stepRefs.current[i] = el;
}}
className="pointer-events-auto mb-[30vh] md:mb-[40vh] bg-white/90 dark:bg-warm-800/90 rounded-xl p-5 md:p-6 backdrop-blur-sm shadow-lg border border-warm-200/40 dark:border-warm-700/40"
>
{step.heading && (
<h3 className="text-xl font-bold text-navy-950 dark:text-warm-100 mb-3 leading-snug">
{step.heading}
</h3>
)}
<div className="text-warm-700 dark:text-warm-300">{step.body}</div>
</div>
))}
<div className="h-[30vh] md:h-[40vh]" />
</div>
</div>
</section>
);
}