import { NextResponse } from 'next/server';
import { getCurrentUser } from '@/lib/auth/session';
import { getCollectionDetail } from '@/lib/account/queries';
import { toCsv } from '@/lib/account/portfolio';

export const dynamic = 'force-dynamic';

const COLUMNS = ['item_id', 'asset_id', 'asset_slug', 'title', 'category', 'variant', 'grader', 'grade', 'cert', 'serial', 'quantity', 'acquired_at', 'purchase_price', 'currency', 'purchase_price_usd', 'source', 'condition', 'value_usd', 'value_source', 'confidence', 'gain_usd', 'gain_pct', 'tags', 'notes'];

export async function GET(req: Request, ctx: { params: Promise<{ id: string }> }) {
  const u = await getCurrentUser();
  if (!u) return NextResponse.json({ error: 'unauthorized' }, { status: 401 });
  const { id } = await ctx.params;
  const detail = await getCollectionDetail(u.id, id);
  if (!detail) return NextResponse.json({ error: 'not found' }, { status: 404 });
  const format = new URL(req.url).searchParams.get('format') ?? 'csv';
  const rows = detail.summary.items.map((i) => {
    const src = detail.items.find((x) => x.id === i.id)!;
    return {
      item_id: i.id,
      asset_id: i.assetId,
      asset_slug: src.assetSlug,
      title: i.title,
      category: i.categorySlug,
      variant: src.variantLabel,
      grader: i.grader,
      grade: i.grade,
      cert: src.certificationNumber,
      serial: src.serial,
      quantity: i.quantity,
      acquired_at: i.acquiredAt,
      purchase_price: src.purchasePriceNative,
      currency: src.acquiredCurrency,
      purchase_price_usd: i.purchasePriceUsd,
      source: src.source,
      condition: src.condition,
      value_usd: i.valueUsd,
      value_source: i.valueSource,
      confidence: i.confidence,
      gain_usd: i.gainUsd,
      gain_pct: i.gainPct,
      tags: src.tags.join('|'),
      notes: src.notes,
    };
  });
  const stamp = new Date().toISOString().slice(0, 10);
  if (format === 'json') {
    return new NextResponse(JSON.stringify({ collection: detail.collection.name, exportedAt: new Date().toISOString(), summary: { valueUsd: detail.summary.valueUsd, costBasisUsd: detail.summary.costBasisUsd, gainUsd: detail.summary.gainUsd, returnPct: detail.summary.returnPct, items: detail.summary.itemCount }, items: rows }, null, 2), { headers: { 'content-type': 'application/json', 'content-disposition': `attachment; filename="rareindex-${detail.collection.publicSlug ?? id}-${stamp}.json"` } });
  }
  return new NextResponse(toCsv(rows, COLUMNS), { headers: { 'content-type': 'text/csv; charset=utf-8', 'content-disposition': `attachment; filename="rareindex-${detail.collection.publicSlug ?? id}-${stamp}.csv"` } });
}