/**
 * OG card for a user profile (`/u/<handle>`).
 *
 * Renders a 1200×630 image with avatar (or initials fallback), display
 * name, @handle, and a stats line (post count + join year). Designed
 * to match the chapter-card OG aesthetic so a feed of links from
 * different parts of the site looks coherent in WhatsApp / Twitter
 * previews.
 *
 * Data comes from the public BFF profile endpoint — no auth required.
 * Failures (missing profile, BFF unreachable) return 404 / 500 instead
 * of a generic image so social scrapers know to fall back to a
 * higher-level card; the share/[code]'s `ogDefault()` shape handles
 * that case.
 */

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 PublicProfile = {
  handle: string;
  name: string;
  avatar_url: string | null;
  joined_at: string;
  post_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 };
}

function initialsFor(name: string): string {
  return (
    name
      .split(/\s+/)
      .filter(Boolean)
      .map((p) => p[0])
      .slice(0, 2)
      .join("")
      .toUpperCase() || "?"
  );
}

function formatJoined(iso: string): string {
  const d = new Date(iso);
  if (Number.isNaN(d.getTime())) return "";
  return `${d.toLocaleString("en-US", { month: "short" })} ${d.getFullYear()}`;
}

export async function GET(
  _request: Request,
  context: { params: Promise<{ handle: string }> },
) {
  try {
    const { handle } = await context.params;
    const profile = await bff<PublicProfile>(
      `/u/${encodeURIComponent(handle)}`,
      { revalidate: 60 },
    ).catch(() => null);
    if (!profile) {
      return new Response("Profile not found", { status: 404 });
    }

    const fonts = await loadFonts();
    const displayName =
      profile.name.length > 40 ? profile.name.slice(0, 37) + "…" : profile.name;
    const stats = [
      `${profile.post_count} post${profile.post_count === 1 ? "" : "s"}`,
      profile.joined_at ? `Joined ${formatJoined(profile.joined_at)}` : null,
    ]
      .filter(Boolean)
      .join(" · ");

    return new ImageResponse(
      (
        <div
          style={{
            width: 1200,
            height: 630,
            display: "flex",
            flexDirection: "column",
            backgroundColor: "#faf5f0",
            fontFamily: "Noto Sans, sans-serif",
            padding: 80,
          }}
        >
          {/* Top row: avatar + identity block */}
          <div
            style={{
              display: "flex",
              flexDirection: "row",
              alignItems: "center",
              gap: 48,
            }}
          >
            {profile.avatar_url ? (
              <img
                src={profile.avatar_url}
                width={220}
                height={220}
                style={{
                  width: 220,
                  height: 220,
                  borderRadius: 110,
                  objectFit: "cover",
                  border: "6px solid #2d2418",
                  flexShrink: 0,
                }}
              />
            ) : (
              <div
                style={{
                  width: 220,
                  height: 220,
                  borderRadius: 110,
                  backgroundColor: "#c47a5a",
                  color: "#faf5f0",
                  display: "flex",
                  alignItems: "center",
                  justifyContent: "center",
                  fontSize: 96,
                  fontWeight: 700,
                  flexShrink: 0,
                }}
              >
                {initialsFor(profile.name)}
              </div>
            )}
            <div
              style={{
                display: "flex",
                flexDirection: "column",
                gap: 6,
                flex: 1,
                minWidth: 0,
              }}
            >
              <div
                style={{
                  fontSize: 60,
                  fontWeight: 700,
                  color: "#2d2418",
                  lineHeight: 1.05,
                  display: "flex",
                  overflow: "hidden",
                }}
              >
                {displayName}
              </div>
              <div style={{ fontSize: 30, color: "#5a4a3a", display: "flex" }}>
                @{profile.handle}
              </div>
              {stats ? (
                <div
                  style={{
                    fontSize: 22,
                    color: "#5a4a3a",
                    marginTop: 12,
                    display: "flex",
                  }}
                >
                  {stats}
                </div>
              ) : null}
            </div>
          </div>

          {/* Footer: branding */}
          <div
            style={{
              marginTop: "auto",
              display: "flex",
              flexDirection: "row",
              alignItems: "center",
              gap: 8,
            }}
          >
            <span style={{ fontSize: 22, color: "#5a4a3a" }}>
              Read quotes shared on
            </span>
            <span style={{ fontSize: 22, color: "#c47a5a", fontWeight: 700 }}>
              prabhupadasays.org
            </span>
          </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("Profile OG image generation failed:", e);
    return new Response("Failed to generate OG image", { status: 500 });
  }
}