import crypto from "crypto";
import fs from "fs";
import path from "path";

const couchUsername = process.env.COUCHDB_USERNAME;
const couchPassword = process.env.COUCHDB_PASSWORD;

function getAuthHeader() {
	if (!couchUsername || !couchPassword) {
		throw new Error("CouchDB credentials not set in environment variables");
	}
	const auth = Buffer.from(`${couchUsername}:${couchPassword}`).toString("base64");
	return `Basic ${auth}`;
}

// === CONFIG ===
const baseUrl = "https://kartta.hel.fi/ws/geoserver/avoindata/wfs";
const layers = [
	"Aluesarjat_avainluvut_2024",
	"Piirijako_pienalue",
	"Piirijako_peruspiiri",
	"Seutukartta_liikenne_paatiet",
	"Seutukartta_liikenne_metroasemat",
	"Seutukartta_liikenne_metro_rata",
	"Seutukartta_liikenne_juna_rata",
	"Seutukartta_liikenne_juna_asema",
	"Seutukartta_aluejako_pienalue",
	"Seutukartta_aluejako_kuntarajat",
	"Seutukartta_maankaytto_jarvet",
	"Seutukartta_maankaytto_joet",
	"Seutukartta_meren_rantaviiva",
	"Toimipisterekisteri_palvelut",
];

const outputDir = path.join(process.cwd(), "app", "data");
const couchUrl = "https://couch.tammi.cc";
const dbName = "helsinki_wfs";

// Ensure output dir
if (!fs.existsSync(outputDir)) {
	fs.mkdirSync(outputDir, { recursive: true });
}

function getHeaders() {
	return new Headers({
		// biome-ignore lint/style/useNamingConvention: database
		Authorization: getAuthHeader(),
		"Content-Type": "application/json",
	});
}

// === COUCHDB HELPERS ===
async function createDatabase() {
	const url = `${couchUrl}/${dbName}`;
	const res = await fetch(url, {
		headers: getHeaders(),
		method: "PUT",
	});
	if (res.ok || res.status === 412) {
		console.log(`Database ${dbName} ready.`);
	} else {
		throw new Error(await res.text());
	}
}

async function ensureDesignDocs() {
	const designDoc = {
		_id: "_design/layers",
		views: {
			// biome-ignore lint/style/useNamingConvention: database
			by_layer: {
				map: `function(doc) {
          if (doc.type === 'feature' && doc.layer) {
            emit(doc.layer, null);
          }
        }`,
			},
		},
	};

	const url = `${couchUrl}/${dbName}/_design/layers`;
	const res = await fetch(url, { headers: getHeaders() });
	if (res.status === 404) {
		await fetch(url, {
			body: JSON.stringify(designDoc),
			headers: getHeaders(),
			method: "PUT",
		});
		console.log("Created design document: layers/by_layer");
	} else if (res.ok) {
		const existing = await res.json();
		designDoc._rev = existing._rev;
		await fetch(url, {
			body: JSON.stringify(designDoc),
			headers: getHeaders(),
			method: "PUT",
		});
		console.log("Updated design document");
	}
}

// === DOWNLOAD ===
async function downloadLayer(layer) {
	const url = `${baseUrl}?service=WFS&version=2.0.0&request=GetFeature&typeName=avoindata:${layer}&outputFormat=json&srsname=EPSG:4326`;
	const res = await fetch(url);
	if (!res.ok) throw new Error(res.statusText);
	const response = await res.json();
	return response;
}

function saveToFile(layer, data) {
	const filePath = path.join(outputDir, `${layer}.geojson`);
	fs.writeFileSync(filePath, JSON.stringify(data, null, "\t"));
	console.log(`Saved: ${layer}.geojson`);
}

// === UPLOAD METADATA ===
async function uploadLayerMetadata(layer, featureCount) {
	const docId = `layer_metadata:${layer}`;

	const doc = {
		_id: docId,
		// biome-ignore lint/style/useNamingConvention: database
		feature_count: featureCount,
		// biome-ignore lint/style/useNamingConvention: database
		last_updated: new Date().toISOString(),
		name: layer,
		projection: "EPSG:4326",
		type: "layer_metadata",
	};

	const url = `${couchUrl}/${dbName}/${docId}`;
	const getRes = await fetch(url, { headers: getHeaders() });
	if (getRes.ok) {
		const existing = await getRes.json();
		doc._rev = existing._rev;
	}
	const putRes = await fetch(url, {
		body: JSON.stringify(doc),
		headers: getHeaders(),
		method: "PUT",
	});
	if (!putRes.ok) throw new Error(await putRes.text());
	console.log(`Metadata updated: ${layer} (${featureCount} features)`);
}

// === UPLOAD SINGLE FEATURE (with deduplication) ===
async function uploadFeature(doc) {
	const url = `${couchUrl}/${dbName}/${doc._id}`;
	const getRes = await fetch(url, { headers: getHeaders() });
	if (getRes.ok) {
		const existing = await getRes.json();
		doc._rev = existing._rev;

		const geomEqual = JSON.stringify(doc.geometry) === JSON.stringify(existing.geometry);
		const propEqual = JSON.stringify(doc.properties) === JSON.stringify(existing.properties);
		if (geomEqual && propEqual) {
			return false; // skipped
		}
	}

	const putRes = await fetch(url, {
		body: JSON.stringify(doc),
		headers: getHeaders(),
		method: "PUT",
	});

	return putRes.ok;
}

// === PROCESS LAYER ===
async function processLayer(layer) {
	const geojson = await downloadLayer(layer);
	if (!geojson || !geojson.features) {
		console.warn(`No features in ${layer} ${geojson}`);
		process.exit(1);
	}

	let uploaded = 0;
	let skipped = 0;

	for (const feature of geojson.features) {
		// Stable ID: use feature.id, or property, or UUID
		const propId =
			feature.id ||
			feature.properties?.id ||
			feature.properties?.tunnus ||
			feature.properties?.objectid ||
			crypto.randomUUID();

		const doc = {
			_id: `feature:${layer}:${propId}`,
			// biome-ignore lint/style/useNamingConvention: database
			downloaded_at: new Date().toISOString(),
			geometry: feature.geometry,
			layer: layer,
			properties: feature.properties || {},
			type: "feature",
		};

		const success = await uploadFeature(doc);
		success ? uploaded++ : skipped++;
	}

	await uploadLayerMetadata(layer, geojson.features.length);
	console.log(`Done: ${layer} | Uploaded: ${uploaded} | Skipped: ${skipped}`);
}

// === MAIN ===
async function main() {
	await createDatabase();
	await ensureDesignDocs();

	for (const layer of layers) {
		await processLayer(layer);
		// Optional: rate limiting
		await new Promise((r) => setTimeout(r, 500));
	}

	console.log("All layers processed.");
}

if (process.argv[1] === new URL(import.meta.url).pathname) {
	main().catch(console.error);
}