import {readFile,writeFile,mkdir,copyFile} from 'node:fs/promises';
import {resolve} from 'node:path';
import {topology} from 'topojson-server';
import {feature} from 'topojson-client';
import {presimplify,quantile,simplify} from 'topojson-simplify';
import {geoConicEqualArea,geoPath,geoArea} from 'd3-geo';
import {createHash} from 'node:crypto';
const root=resolve(import.meta.dirname,'../..');
const source=JSON.parse(await readFile(resolve(root,'assets/geo/geoBoundaries-RUS-ADM1_simplified.geojson'),'utf8'));
if(source.type!=='FeatureCollection'||source.features.length!==83)throw Error('Expected pinned RUS ADM1 / 83 features');
let coordinates=0;const bounds=[Infinity,Infinity,-Infinity,-Infinity];let westOf180=0;
function inspect(a){if(typeof a[0]==='number'){
 if(!Number.isFinite(a[0])||!Number.isFinite(a[1])||Math.abs(a[0])>180||Math.abs(a[1])>90)throw Error('Invalid WGS84 coordinate');
 coordinates++;bounds[0]=Math.min(bounds[0],a[0]);bounds[1]=Math.min(bounds[1],a[1]);bounds[2]=Math.max(bounds[2],a[0]);bounds[3]=Math.max(bounds[3],a[1]);if(a[0]<-160)westOf180++;
}else a.forEach(inspect);}
source.features.forEach(f=>{if(!['Polygon','MultiPolygon'].includes(f.geometry.type))throw Error('Unexpected geometry');inspect(f.geometry.coordinates);});
const prepared=presimplify(topology({regions:source},100000));
const weight=quantile(prepared,0.06);
const topo=simplify(prepared,weight);
let light=feature(topo,topo.objects.regions);
// D3 expects clockwise exterior spherical rings; normalize for projection only.
// Keep original source unchanged; small regional polygons must cover < hemisphere.
for(const f of light.features){if(geoArea(f)>2*Math.PI){
 const polygons=f.geometry.type==='Polygon'?[f.geometry.coordinates]:f.geometry.coordinates;
 for(const p of polygons)for(const ring of p)ring.reverse();
}}
if(light.features.length!==83)throw Error('Lost regions');
const projection=geoConicEqualArea().parallels([50,70]).rotate([-105,0]).center([0,60]).fitExtent([[20,20],[1180,690]],light);
const path=geoPath(projection).digits(1);
const regions=light.features.map(f=>({id:f.properties.shapeISO||f.properties.shapeID,name:f.properties.shapeName,sourceID:f.properties.shapeID,path:path(f),labelPoint:path.centroid(f)}));
if(regions.some(r=>!r.path||r.path.includes('NaN')||r.labelPoint.some(v=>!Number.isFinite(v))))throw Error('Invalid projected geometry');
for(const f of light.features){function round(a){if(typeof a[0]==='number'){a[0]=+a[0].toFixed(5);a[1]=+a[1].toFixed(5);}else a.forEach(round);}round(f.geometry.coordinates);}
await writeFile(resolve(root,'assets/geo/russia-regions.geojson'),JSON.stringify(light));
await writeFile(resolve(root,'assets/geo/russia-regions.paths.json'),JSON.stringify({viewBox:'0 0 1200 710',projection:'Conic equal area, parallels 50/70, central meridian 105 E',regions}));
const escape=s=>s.replaceAll('&','&amp;').replaceAll('<','&lt;').replaceAll('"','&quot;');
const svg=`<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1200 710" role="img"><title>Russia ADM1 source geometry diagnostic — geoBoundaries / OSM</title><rect width="1200" height="710" fill="#FBF7EA"/>${regions.map(r=>`<path d="${r.path}" fill="#E9DDB8" stroke="#1C1B19" stroke-width="0.55"><title>${escape(r.name)}</title></path>`).join('')}<text x="20" y="700" font-family="sans-serif" font-size="12">geoBoundaries / OpenStreetMap contributors. Dataset: 2017; 83 units. Geometry diagnostic.</text></svg>`;
await writeFile(resolve(root,'dev/artifacts/setup/russia-geometry.svg'),svg);
const report={date:new Date().toISOString(),features:83,sourceCoordinates:coordinates,sourceBounds:bounds,antimeridianCoordinates:westOf180,sourceYear:2017,retainedWeightedFraction:0.06,weight,projectedPaths:regions.length,sourceSHA256:createHash('sha256').update(await readFile(resolve(root,'assets/geo/geoBoundaries-RUS-ADM1_simplified.geojson'))).digest('hex'),files:{geojson:Buffer.byteLength(JSON.stringify(light)),paths:Buffer.byteLength(JSON.stringify(regions))},names:regions.map(({id,name})=>({id,name}))};
await writeFile(resolve(root,'dev/artifacts/setup/map-validation.json'),JSON.stringify(report,null,2));
for(const pkg of ['d3-geo','topojson-server','topojson-client','topojson-simplify']){
 await copyFile(resolve(root,`dev/tools/node_modules/${pkg}/LICENSE`),resolve(root,`docs/licenses/${pkg}-LICENSE`));
}
console.log({features:report.features,bounds,coordinates,antimeridianCoordinates:westOf180,files:report.files});