/* eslint-disable @next/next/no-img-element -- Satori (ImageResponse) only
   renders raw <img>; next/image doesn't work inside OG image generation. */
/**
 * OG card for a public collection (`/c/<id>`).
 *
 * Renders a 1200×630 image with the collection title as the centrepiece,
 * an item-count line, and the cover image dimmed behind it when present
 * (flat cream otherwise). Matches the post/profile card aesthetic.
 *
 * Data comes from the public BFF collection endpoint. The server fetch is
 * unauthenticated, so private collections return 403 → we 404 here (a
 * private collection never unfurls, which is the correct privacy stance).
 */

import { ImageResponse } from "next/og";
import { readFile } from "node:fs/promises";
import { join } from "node:path";
import { bff } from "@/lib/bff";

export const runtime = "nodejs";

type CollectionEnvelope = {
  collection: {
    id: string;
    title: string;
    description: string | null;
    cover_url: string | null;
    is_public: boolean;
    item_count: number;
  };
};

let notoRegularData: Buffer | null = null;
let notoBoldData: Buffer | null = null;

async function loadFonts() {
  const fontsDir = join(process.cwd(), "public/fonts/Noto_Sans/static");
  if (!notoRegularData) {
    notoRegularData = await readFile(join(fontsDir, "NotoSans-Regular.ttf"));
  }
  if (!notoBoldData) {
    notoBoldData = await readFile(join(fontsDir, "NotoSans-Bold.ttf"));
  }
  return { regular: notoRegularData, bold: notoBoldData };
}

export async function GET(
  _request: Request,
  context: { params: Promise<{ id: string }> },
) {
  try {
    const { id } = await context.params;
    const data = await bff<CollectionEnvelope>(
      `/collections/${encodeURIComponent(id)}`,
      { revalidate: 60 },
    ).catch(() => null);
    const c = data?.collection;
    if (!c || !c.is_public) {
      return new Response("Collection not found", { status: 404 });
    }

    const fonts = await loadFonts();
    const title = c.title.length > 90 ? c.title.slice(0, 87) + "…" : c.title;
    const description = c.description?.trim()
      ? c.description.length > 160
        ? c.description.slice(0, 157) + "…"
        : c.description
      : "";
    const count = `${c.item_count} post${c.item_count === 1 ? "" : "s"}`;
    const bgImageUrl = c.cover_url;
    const hasImage = !!bgImageUrl;

    const textPrimary = hasImage ? "#ffffff" : "#2d2418";
    const textSecondary = hasImage ? "rgba(255,255,255,0.85)" : "#5a4a3a";
    const accent = hasImage ? "#ffd9a8" : "#c47a5a";

    return new ImageResponse(
      (
        <div
          style={{
            width: 1200,
            height: 630,
            display: "flex",
            flexDirection: "column",
            backgroundColor: hasImage ? "#1a1410" : "#faf5f0",
            fontFamily: "Noto Sans, sans-serif",
            position: "relative",
            padding: 80,
          }}
        >
          {hasImage ? (
            <>
              <img
                alt=""
                src={bgImageUrl}
                width={1200}
                height={630}
                style={{
                  position: "absolute",
                  top: 0,
                  left: 0,
                  width: 1200,
                  height: 630,
                  objectFit: "cover",
                  filter: "brightness(0.45)",
                }}
              />
              <div
                style={{
                  position: "absolute",
                  top: 0,
                  left: 0,
                  width: 1200,
                  height: 630,
                  background:
                    "linear-gradient(to top, rgba(0,0,0,0.75), rgba(0,0,0,0.1))",
                }}
              />
            </>
          ) : null}

          {/* Eyebrow */}
          <div
            style={{
              display: "flex",
              fontSize: 24,
              fontWeight: 700,
              letterSpacing: 6,
              textTransform: "uppercase",
              color: accent,
              zIndex: 1,
            }}
          >
            Collection
          </div>

          {/* Title — the centrepiece */}
          <div
            style={{
              display: "flex",
              fontSize: title.length > 48 ? 60 : 76,
              fontWeight: 700,
              color: textPrimary,
              lineHeight: 1.15,
              marginTop: 24,
              maxHeight: 320,
              overflow: "hidden",
              zIndex: 1,
            }}
          >
            {title}
          </div>

          {description ? (
            <div
              style={{
                display: "flex",
                fontSize: 28,
                color: textSecondary,
                lineHeight: 1.4,
                marginTop: 24,
                maxHeight: 120,
                overflow: "hidden",
                zIndex: 1,
              }}
            >
              {description}
            </div>
          ) : null}

          <div style={{ flex: 1, display: "flex" }} />

          {/* Footer: count + branding */}
          <div
            style={{
              display: "flex",
              flexDirection: "row",
              alignItems: "center",
              justifyContent: "space-between",
              zIndex: 1,
            }}
          >
            <div style={{ fontSize: 24, color: textSecondary, display: "flex" }}>
              {count}
            </div>
            <div style={{ fontSize: 22, color: accent, fontWeight: 700 }}>
              prabhupadasays.org
            </div>
          </div>
        </div>
      ),
      {
        width: 1200,
        height: 630,
        fonts: [
          {
            name: "Noto Sans",
            data: fonts.regular,
            style: "normal" as const,
            weight: 400,
          },
          {
            name: "Noto Sans",
            data: fonts.bold,
            style: "normal" as const,
            weight: 700,
          },
        ],
      },
    );
  } catch (e) {
    console.error("Collection OG image generation failed:", e);
    return new Response("Failed to generate OG image", { status: 500 });
  }
}