// Car pokedex queries (/trackers/cars). Public, read-only; data is written only by
// scripts/cars-import.ts.
import { db } from '#lib/server/db/index.js';
import { carBrands, carModels, carPhotos, carVariants } from '#lib/server/db/schema/index.js';
import { and, arrayContains, asc, desc, eq, gt, gte, ilike, lte, sql, type SQL } from 'drizzle-orm';
import { BODIES, DRIVES, FUELS, SORTS, type CarCard, type CarSort } from '#lib/cars/shared.js';

export const PAGE_SIZE = 60;

export type CarFilters = {
	q: string;
	brand: string;
	fuel: string;
	body: string;
	drive: string;
	market: '' | 'nl' | 'us';
	from: number | null;
	to: number | null;
	sort: CarSort;
	page: number;
};

const pick = <T extends string>(value: string | null, allowed: readonly T[]): T | '' =>
	allowed.includes(value as T) ? (value as T) : '';
const year = (value: string | null) => {
	const n = Number(value);
	return value && Number.isInteger(n) && n >= 1880 && n <= 2100 ? n : null;
};

export function parseFilters(params: URLSearchParams): CarFilters {
	const sort = params.get('sort');
	return {
		q: (params.get('q') ?? '').trim().slice(0, 80),
		brand: (params.get('brand') ?? '').replace(/[^a-z0-9-]/g, '').slice(0, 60),
		fuel: pick(params.get('fuel'), FUELS),
		body: pick(params.get('body'), BODIES),
		drive: pick(params.get('drive'), DRIVES),
		market: pick(params.get('market'), ['nl', 'us'] as const),
		from: year(params.get('from')),
		to: year(params.get('to')),
		sort: sort && sort in SORTS ? (sort as CarSort) : 'popular',
		page: Math.min(Math.max(1, Math.floor(Number(params.get('page')) || 1)), 1000)
	};
}

const cardColumns = {
	dex: carModels.dex,
	slug: carModels.slug,
	name: carModels.name,
	brandSlug: carBrands.slug,
	brandName: carBrands.name,
	brandLogo: carBrands.logo,
	firstYear: carModels.firstYear,
	lastYear: carModels.lastYear,
	fuels: carModels.fuels,
	bodies: carModels.bodies,
	nlCount: carModels.nlCount,
	nlPriceLatest: carModels.nlPriceLatest,
	powerKwMax: carModels.powerKwMax,
	photo: carModels.photo
};

const escapeLike = (s: string) => s.replace(/[\\%_]/g, (c) => `\\${c}`);

export async function searchCars(f: CarFilters): Promise<{ cars: CarCard[]; total: number }> {
	const where: SQL[] = [];
	for (const word of f.q.toLowerCase().split(/\s+/).filter(Boolean).slice(0, 6))
		where.push(ilike(carModels.search, `%${escapeLike(word)}%`));
	if (f.brand) where.push(eq(carBrands.slug, f.brand));
	if (f.fuel) where.push(arrayContains(carModels.fuels, [f.fuel]));
	if (f.body) where.push(arrayContains(carModels.bodies, [f.body]));
	if (f.drive) where.push(arrayContains(carModels.drives, [f.drive]));
	if (f.market === 'nl') where.push(gt(carModels.nlCount, 0));
	if (f.market === 'us') where.push(gt(carModels.variantCount, 0));
	if (f.from) where.push(gte(carModels.lastYear, f.from));
	if (f.to) where.push(lte(carModels.firstYear, f.to));
	const order = {
		dex: [asc(carModels.dex)],
		popular: [desc(carModels.nlCount), asc(carModels.dex)],
		name: [asc(carModels.name), asc(carBrands.name)],
		newest: [desc(carModels.lastYear), desc(carModels.firstYear), desc(carModels.nlCount)],
		oldest: [asc(carModels.firstYear), asc(carModels.dex)],
		cheap: [sql`${carModels.nlPriceLatest} asc nulls last`, desc(carModels.nlCount)],
		power: [sql`${carModels.powerKwMax} desc nulls last`, asc(carModels.dex)],
		efficient: [sql`${carModels.co2Min} asc nulls last`, desc(carModels.nlCount)]
	}[f.sort];
	const condition = where.length ? and(...where) : undefined;
	const [cars, [{ total }]] = await Promise.all([
		db
			.select(cardColumns)
			.from(carModels)
			.innerJoin(carBrands, eq(carBrands.id, carModels.brandId))
			.where(condition)
			.orderBy(...order)
			.limit(PAGE_SIZE)
			.offset((f.page - 1) * PAGE_SIZE),
		db
			.select({ total: sql<number>`count(*)::int` })
			.from(carModels)
			.innerJoin(carBrands, eq(carBrands.id, carModels.brandId))
			.where(condition)
	]);
	return { cars, total };
}

export type BrandTile = {
	slug: string;
	name: string;
	models: number;
	nlCount: number;
	country: string | null;
	logo: string | null;
};
type Overview = {
	/** Alphabetical (for the filter); `byNl` has the same brands, most common in NL first. */
	brands: BrandTile[];
	byNl: BrandTile[];
	stats: { brands: number; models: number; variants: number; nlCars: number };
};
let overviewCache: { at: number; value: Overview } | null = null;

/** Brand list for the filter and headline counts; cached for 10 minutes. */
export async function carOverview(): Promise<Overview> {
	if (overviewCache && Date.now() - overviewCache.at < 600_000) return overviewCache.value;
	const [brands, [counts]] = await Promise.all([
		db
			.select({
				slug: carBrands.slug,
				name: carBrands.name,
				models: carBrands.modelCount,
				nlCount: carBrands.nlCount,
				country: carBrands.country,
				logo: carBrands.logo
			})
			.from(carBrands)
			.orderBy(asc(carBrands.name)),
		db
			.select({
				models: sql<number>`count(*)::int`,
				variants: sql<number>`coalesce(sum(${carModels.variantCount}), 0)::int`,
				nlCars: sql<number>`coalesce(sum(${carModels.nlCount}), 0)::bigint`
			})
			.from(carModels)
	]);
	const value = {
		brands,
		byNl: [...brands].sort(
			(a, b) => b.nlCount - a.nlCount || b.models - a.models || a.name.localeCompare(b.name)
		),
		stats: {
			brands: brands.length,
			models: counts.models,
			variants: counts.variants,
			nlCars: Number(counts.nlCars)
		}
	};
	if (value.stats.models) overviewCache = { at: Date.now(), value };
	return value;
}

export async function getBrand(slug: string) {
	const [brand] = await db.select().from(carBrands).where(eq(carBrands.slug, slug)).limit(1);
	if (!brand) return null;
	const models = await db
		.select(cardColumns)
		.from(carModels)
		.innerJoin(carBrands, eq(carBrands.id, carModels.brandId))
		.where(eq(carModels.brandId, brand.id))
		.orderBy(desc(carModels.nlCount), desc(carModels.variantCount), asc(carModels.name));
	const [hero] = brand.photo
		? await db
				.select({
					file: carPhotos.file,
					author: carPhotos.author,
					license: carPhotos.license,
					licenseUrl: carPhotos.licenseUrl,
					model: carModels.name
				})
				.from(carPhotos)
				.innerJoin(carModels, eq(carModels.id, carPhotos.modelId))
				.where(and(eq(carModels.brandId, brand.id), eq(carPhotos.thumb, brand.photo)))
				.limit(1)
		: [];
	return { brand, models, hero: hero ?? null };
}

export async function getModel(brandSlug: string, modelSlug: string) {
	const [row] = await db
		.select({ model: carModels, brand: carBrands })
		.from(carModels)
		.innerJoin(carBrands, eq(carBrands.id, carModels.brandId))
		.where(and(eq(carBrands.slug, brandSlug), eq(carModels.slug, modelSlug)))
		.limit(1);
	if (!row) return null;
	const [variants, neighbours, photos] = await Promise.all([
		db
			.select()
			.from(carVariants)
			.where(eq(carVariants.modelId, row.model.id))
			.orderBy(desc(carVariants.year), asc(carVariants.name), asc(carVariants.engineL)),
		db
			.select({
				dex: carModels.dex,
				slug: carModels.slug,
				name: carModels.name,
				brandSlug: carBrands.slug
			})
			.from(carModels)
			.innerJoin(carBrands, eq(carBrands.id, carModels.brandId))
			.where(
				sql`${carModels.dex} in (
					(select max(dex) from cars.models where dex < ${row.model.dex}),
					(select min(dex) from cars.models where dex > ${row.model.dex}))`
			),
		db
			.select({
				file: carPhotos.file,
				kind: carPhotos.kind,
				caption: carPhotos.caption,
				thumb: carPhotos.thumb,
				width: carPhotos.width,
				height: carPhotos.height,
				author: carPhotos.author,
				license: carPhotos.license,
				licenseUrl: carPhotos.licenseUrl
			})
			.from(carPhotos)
			.where(eq(carPhotos.modelId, row.model.id))
			.orderBy(asc(carPhotos.position))
	]);
	return {
		...row,
		variants,
		photos,
		prev: neighbours.find((n) => n.dex < row.model.dex) ?? null,
		next: neighbours.find((n) => n.dex > row.model.dex) ?? null
	};
}

/** A random model, favouring cars people actually drive (in NL or EPA-tested). */
export async function randomCar() {
	const [row] = await db
		.select({ slug: carModels.slug, brandSlug: carBrands.slug })
		.from(carModels)
		.innerJoin(carBrands, eq(carBrands.id, carModels.brandId))
		.where(sql`${carModels.nlCount} >= 100 or ${carModels.variantCount} >= 5`)
		.orderBy(sql`random()`)
		.limit(1);
	return row ?? null;
}