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

export const runtime = "nodejs";

// Cache font data at module level so they're only loaded once
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) {
  try {
    const { searchParams } = new URL(request.url);

    const title = searchParams.get("title") || "Prabhupāda Says";
    const detail = searchParams.get("detail") || "";
    const rawQuote = searchParams.get("quote") || "";

    // Fallback: if no quote provided, generate one from context
    const quote =
      rawQuote ||
      (title === "Prabhupāda Says"
        ? "Browse the original, unedited books, letters, and teachings of His Divine Grace A.C. Bhaktivedanta Swami Prabhupāda — presented as they are."
        : `Read ${title}${detail ? ` — ${detail}` : ""} by His Divine Grace A.C. Bhaktivedanta Swami Prabhupāda`);

    // Truncate for readability and to prevent overflow
    const displayTitle = title.length > 60 ? title.slice(0, 57) + "..." : title;
    const displayDetail =
      detail.length > 80 ? detail.slice(0, 77) + "..." : detail;
    const displayQuote =
      quote.length > 220 ? quote.slice(0, 217) + "..." : quote;

    // Load fonts and image
    const fonts = await loadFonts();

    const imgData = await readFile(
      join(process.cwd(), "public/images/og-left-prabhupada-reading.png"),
      "base64",
    );
    const imgSrc = `data:image/png;base64,${imgData}`;

    return new ImageResponse(
      <div
        style={{
          width: 1200,
          height: 630,
          display: "flex",
          flexDirection: "row",
          backgroundColor: "#faf5f0",
          fontFamily: "Noto Sans, sans-serif",
          overflow: "hidden",
          position: "relative",
        }}
      >
        {/* Left side — image + branding */}
        <div
          style={{
            width: 460,
            height: 630,
            display: "flex",
            alignItems: "center",
            justifyContent: "center",
            flexShrink: 0,
            padding: 20,
          }}
        >
          {/* Prabhupāda image — already contains quote mark and branding */}
          <img
            src={imgSrc}
            width={420}
            height={590}
            style={{
              objectFit: "contain",
              objectPosition: "center",
            }}
          />
        </div>

        {/* Right side — content */}
        <div
          style={{
            flex: 1,
            display: "flex",
            flexDirection: "column",
            justifyContent: "center",
            paddingTop: 50,
            paddingRight: 60,
            paddingBottom: 50,
            paddingLeft: 60,
            gap: 16,
          }}
        >
          {/* Title */}
          <div
            style={{
              fontSize: 36,
              fontWeight: 700,
              color: "#2d2418",
              lineHeight: 1.4,
              display: "flex",
              overflow: "hidden",
              maxHeight: 104,
            }}
          >
            {displayTitle}
          </div>

          {/* Detail (chapter, verse, etc.) */}
          {displayDetail ? (
            <div
              style={{
                fontSize: 22,
                fontWeight: 700,
                color: "#5a4a3a",
                lineHeight: 1.3,
                display: "flex",
                overflow: "hidden",
                maxHeight: 30,
              }}
            >
              {displayDetail}
            </div>
          ) : null}

          {/* Quote text */}
          {displayQuote ? (
            <div
              style={{
                display: "flex",
                flexDirection: "column",
                marginTop: 16,
                overflow: "hidden",
                maxHeight: 180,
              }}
            >
              <div
                style={{
                  fontSize: 24,
                  color: "#3d3228",
                  lineHeight: 1.5,
                  display: "flex",
                  overflow: "hidden",
                }}
              >
                {displayQuote}
              </div>
            </div>
          ) : null}

          {/* Read more */}
          <div
            style={{
              display: "flex",
              flexDirection: "row",
              alignItems: "center",
              gap: 6,
              marginTop: 16,
            }}
          >
            <span
              style={{
                fontSize: 20,
                fontWeight: 700,
                color: "#5a4a3a",
              }}
            >
              Read more at
            </span>
            <span
              style={{
                fontSize: 20,
                fontWeight: 700,
                color: "#c47a5a",
              }}
            >
              prabhupadasays.org
            </span>
          </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("OG image generation failed:", e);
    return new Response("Failed to generate OG image", { status: 500 });
  }
}