import satori from "satori";
import { Resvg } from "@resvg/resvg-js";
import sharp from "sharp";
import {
  readFileSync,
  existsSync,
  readdirSync,
  writeFileSync,
  mkdirSync,
} from "node:fs";
import path from "node:path";

const W = 1200;
const H = 630;
const contentDir = "src/content/docs";

const pages: Record<string, string> = {
  index: "だれもがしあわせに暮らせるまちへ",
  jisseki: "実績",
  policy: "私の方針",
  support: "ご支援",
  contact: "コンタクト",
  "whisper-to-ai-moji-okoshi":
    "無料・超高精度のWhisperで文字起こしする方法（＋α）",
  "textlint-guide": "textlintで文章校正する方法",
  "bluebey": "ぶるべー スタジオ",
  "koubunsyo-kanri": "公文書管理の不正追及の軌跡",
  "gyosei-fufuku-sinsa": "行政不服審査会の問題追及の軌跡",
  "ijime-judai-jitai": "いじめ重大事態への対応の軌跡",
  "fukushi-shisetsu-gyakutai": "障害者福祉施設における虐待通報対応の軌跡",
  "aiki-kouen": "合気公園の軌跡",
  "joutyo-koteikyu": "情緒固定級の軌跡",
  "kajo-seigen-kanwa": "過剰な制限緩和の軌跡",
  "saresio-kaihatu": "東京サレジオ学園北側開発問題の軌跡",
  "vaccine-kyuusai-tekiseika": "ワクチン副反応救済制度の適正化の軌跡",
  "dislexia-taiou": "ディスレクシア（読み書き障害）対応の軌跡",
  "konan-eisei-kumiai": "湖南衛生組合の議員報酬・給与見直しの軌跡",
  "ippan-situmon": "一般質問",
  media: "メディア掲載",
};

function findMdxFiles(dir: string): string[] {
  if (!existsSync(dir)) return [];
  const files: string[] = [];
  for (const entry of readdirSync(dir, { withFileTypes: true })) {
    if (entry.name.startsWith(".") || entry.name.startsWith("_")) continue;
    const full = path.join(dir, entry.name);
    if (entry.isDirectory()) files.push(...findMdxFiles(full));
    else if (entry.name.endsWith(".mdx")) files.push(full);
  }
  return files;
}

function readTitle(filePath: string): string | null {
  try {
    const content = readFileSync(filePath, "utf-8");
    const m =
      content.match(/^title:\s*"(.+?)"/m) ?? content.match(/^title:\s*(.+)/m);
    return m?.[1] ?? null;
  } catch {
    return null;
  }
}

export async function getStaticPaths() {
  const slugs = new Set<string>();
  // Manual pages
  for (const s of Object.keys(pages)) slugs.add(s);
  // Auto-discover ippan-situmon / iinkai pages
  for (const dir of ["ippan-situmon", "iinkai", "kodaira-data"]) {
    for (const f of findMdxFiles(path.join(contentDir, dir))) {
      const s = f
        .replace(/\\/g, "/")
        .replace(contentDir + "/", "")
        .replace(/\.mdx$/, "")
        .replace(/\/index$/, "");
      if (s) slugs.add(s);
    }
  }
  return [...slugs]
    .filter((s) => s.length > 0)
    .map((slug) => ({ params: { slug: slug.replace(/\//g, "--") } }));
}

const fontBuffer = readFileSync("node_modules/.noto-sans-jp.otf");
const faceiconBuffer = readFileSync("public/img/faceicon.jpg");
const faceiconBase64 = `data:image/jpeg;base64,${faceiconBuffer.toString("base64")}`;

const NAME = "小平市議 安竹洋平";
const LABEL = "KODAIRA CITY COUNCIL";
const TAGLINE = "だれもが しあわせに 暮らせるまちへ";

// 星空背景は全ページ共通なので、ビルド中に1回だけ生成して使い回す。
function mulberry32(a: number) {
  return function () {
    a |= 0;
    a = (a + 0x6d2b79f5) | 0;
    let t = Math.imul(a ^ (a >>> 15), 1 | a);
    t = (t + Math.imul(t ^ (t >>> 7), 61 | t)) ^ t;
    return ((t ^ (t >>> 14)) >>> 0) / 4294967296;
  };
}

const baseGradient = () =>
  Buffer.from(
    `<svg xmlns="http://www.w3.org/2000/svg" width="${W}" height="${H}"><defs><linearGradient id="g" x1="0" y1="0" x2="1" y2="1"><stop offset="0" stop-color="#080b1c"/><stop offset="0.32" stop-color="#10163b"/><stop offset="0.66" stop-color="#23246e"/><stop offset="1" stop-color="#4b3aa8"/></linearGradient></defs><rect width="${W}" height="${H}" fill="url(#g)"/></svg>`,
  );

const nebulaSvg = () =>
  Buffer.from(
    `<svg xmlns="http://www.w3.org/2000/svg" width="${W}" height="${H}"><ellipse cx="150" cy="80" rx="450" ry="320" fill="#6366f1" opacity="0.62"/><ellipse cx="1090" cy="600" rx="490" ry="340" fill="#06b6d4" opacity="0.55"/><ellipse cx="900" cy="70" rx="370" ry="260" fill="#8b5cf6" opacity="0.5"/><ellipse cx="640" cy="360" rx="360" ry="220" fill="#3b82f6" opacity="0.22"/></svg>`,
  );

const milkyWay = () =>
  Buffer.from(
    `<svg xmlns="http://www.w3.org/2000/svg" width="${W}" height="${H}"><g transform="rotate(-24 600 315)"><ellipse cx="600" cy="315" rx="780" ry="95" fill="#93c5fd" opacity="0.38"/><ellipse cx="600" cy="315" rx="720" ry="42" fill="#ffffff" opacity="0.22"/></g></svg>`,
  );

const arcsSvg = () =>
  Buffer.from(
    `<svg xmlns="http://www.w3.org/2000/svg" width="${W}" height="${H}"><circle cx="985" cy="330" r="360" fill="none" stroke="#c7d2fe" stroke-opacity="0.18" stroke-width="1.5"/><circle cx="985" cy="330" r="472" fill="none" stroke="#a5f3fc" stroke-opacity="0.12" stroke-width="1"/></svg>`,
  );

function starsSvg(seed: number, n: number) {
  const rnd = mulberry32(seed);
  let s = `<svg xmlns="http://www.w3.org/2000/svg" width="${W}" height="${H}"><defs><radialGradient id="sg"><stop offset="0" stop-color="#ffffff" stop-opacity="0.95"/><stop offset="1" stop-color="#ffffff" stop-opacity="0"/></radialGradient></defs>`;
  for (let i = 0; i < n; i++) {
    const x = rnd() * W;
    const y = rnd() * H;
    const r = 0.35 + rnd() * 1.8;
    const o = 0.18 + rnd() * 0.75;
    const col = rnd() > 0.82 ? "#dbeafe" : "#ffffff";
    s += `<circle cx="${x.toFixed(1)}" cy="${y.toFixed(1)}" r="${r.toFixed(2)}" fill="${col}" opacity="${o.toFixed(2)}"/>`;
  }
  for (let i = 0; i < 8; i++) {
    const x = 520 + rnd() * 660;
    const y = 40 + rnd() * 550;
    const size = 5 + rnd() * 9;
    const o = 0.6 + rnd() * 0.38;
    const col = rnd() > 0.5 ? "#e0f2fe" : "#ffffff";
    s += `<circle cx="${x.toFixed(1)}" cy="${y.toFixed(1)}" r="${(size * 3).toFixed(1)}" fill="url(#sg)" opacity="${(o * 0.45).toFixed(2)}"/>`;
    const q = size * 0.22;
    s += `<path d="M ${x} ${y - size} L ${x + q} ${y - q} L ${x + size} ${y} L ${x + q} ${y + q} L ${x} ${y + size} L ${x - q} ${y + q} L ${x - size} ${y} L ${x - q} ${y - q} Z" fill="${col}" opacity="${o.toFixed(2)}"/>`;
  }
  s += `</svg>`;
  return Buffer.from(s);
}

const leftOverlay = () =>
  Buffer.from(
    `<svg xmlns="http://www.w3.org/2000/svg" width="${W}" height="${H}"><defs><linearGradient id="l" x1="0" y1="0" x2="1" y2="0"><stop offset="0" stop-color="#05070f" stop-opacity="0.86"/><stop offset="0.4" stop-color="#05070f" stop-opacity="0.62"/><stop offset="0.62" stop-color="#05070f" stop-opacity="0.22"/><stop offset="0.8" stop-color="#05070f" stop-opacity="0"/></linearGradient></defs><rect width="${W}" height="${H}" fill="url(#l)"/></svg>`,
  );

async function buildBackground(): Promise<Buffer> {
  const base = await sharp(baseGradient()).png().toBuffer();
  const neb = await sharp(nebulaSvg()).blur(80).png().toBuffer();
  const mw = await sharp(milkyWay()).blur(55).png().toBuffer();
  return sharp(base)
    .composite([
      { input: neb },
      { input: mw, blend: "screen" },
      { input: arcsSvg() },
      { input: starsSvg(20261104, 260) },
      { input: leftOverlay() },
    ])
    .png()
    .toBuffer();
}

let backgroundPromise: Promise<Buffer> | null = null;
function getBackground(): Promise<Buffer> {
  if (!backgroundPromise) backgroundPromise = buildBackground();
  return backgroundPromise;
}

function textLayer(title: string) {
  // 長いタイトルでもはみ出さないよう、文字数に応じて少しだけ縮める
  const titleSize = title.length > 40 ? 46 : title.length > 30 ? 52 : 60;
  // ホームはタイトルとタグラインが実質同じなので、タグラインを省く
  const isHome =
    title.replace(/\s/g, "") === TAGLINE.replace(/\s/g, "");

  return {
    type: "div",
    props: {
      style: {
        display: "flex",
        width: `${W}px`,
        height: `${H}px`,
        alignItems: "center",
        padding: "64px 80px",
        gap: "56px",
        position: "relative",
        fontFamily: "Noto",
        color: "#ffffff",
      },
      children: [
        {
          type: "div",
          props: {
            style: {
              display: "flex",
              padding: "6px",
              borderRadius: "50%",
              background: "linear-gradient(135deg,#22d3ee,#818cf8)",
              flexShrink: "0",
            },
            children: [
              {
                type: "img",
                props: {
                  src: faceiconBase64,
                  width: 168,
                  height: 168,
                  style: { borderRadius: "50%" },
                },
              },
            ],
          },
        },
        {
          type: "div",
          props: {
            style: {
              display: "flex",
              flexDirection: "column",
              gap: "18px",
              flex: "1",
            },
            children: [
              {
                type: "div",
                props: {
                  style: {
                    fontSize: "22px",
                    letterSpacing: "3.5px",
                    color: "rgba(214,224,255,0.85)",
                  },
                  children: LABEL,
                },
              },
              {
                type: "div",
                props: {
                  style: {
                    fontSize: `${titleSize}px`,
                    fontWeight: 700,
                    lineHeight: 1.16,
                    letterSpacing: "-0.01em",
                  },
                  children: title,
                },
              },
              {
                type: "div",
                props: {
                  style: {
                    width: "128px",
                    height: "7px",
                    borderRadius: "4px",
                    background: "linear-gradient(90deg,#22d3ee,#818cf8)",
                  },
                },
              },
              ...(isHome
                ? []
                : [
                    {
                      type: "div",
                      props: {
                        style: { fontSize: "30px", color: "#c7d2fe" },
                        children: TAGLINE,
                      },
                    },
                  ]),
              {
                type: "div",
                props: {
                  style: {
                    display: "flex",
                    alignItems: "center",
                    paddingTop: "16px",
                    borderTop: "1px solid rgba(255,255,255,0.22)",
                    fontSize: "31px",
                    fontWeight: 700,
                    color: "#ffffff",
                  },
                  children: [{ type: "div", props: { children: NAME } }],
                },
              },
            ],
          },
        },
      ],
    },
  };
}

export async function GET({ params }: { params: { slug: string } }) {
  const slug = params.slug;
  // まずそのままマッチ（koubunsyo-kanri などの手動ページ）
  let title = pages[slug];
  if (!title) {
    const fileSlug = slug.replace(/--/g, "/");
    title = pages[fileSlug];
    if (!title) {
      title =
        readTitle(path.join(contentDir, fileSlug + ".mdx")) ??
        readTitle(path.join(contentDir, fileSlug, "index.mdx")) ??
        "小平市議 安竹洋平 公式サイト";
    }
  }
  // 一般質問の月例会インデックスページ: 年度・月を補完
  const mm = slug.match(/^ippan-situmon--(r\d+d)--(\d+gatu)$/);
  if (mm) {
    const reiwa = mm[1].replace(
      /^r(\d+)d$/,
      (_, n) => `令和${n === "1" ? "元" : n}年`,
    );
    const month = mm[2].replace(/(\d+)gatu/, "$1月");
    title = `${reiwa}${month}定例会`;
  }

  // Check cache: if title hash matches, return cached JPEG from node_modules/.og-cache
  const cacheDir = path.join(process.cwd(), "node_modules", ".og-cache");
  const cacheFile = path.join(cacheDir, `${slug}.jpg`);
  const cacheJsonPath = path.join(cacheDir, ".og-cache.json");

  let cache: Record<string, string> = {};
  if (existsSync(cacheJsonPath)) {
    cache = JSON.parse(readFileSync(cacheJsonPath, "utf-8"));
  }

  const { createHash } = await import("node:crypto");
  // デザインを変えたらこのバージョンを上げる（キャッシュを無効化する）
  const DESIGN_VERSION = "space-v9b-3";
  const titleHash = createHash("md5")
    .update(`${DESIGN_VERSION}|${title}`)
    .digest("hex");

  if (existsSync(cacheFile) && cache[slug] === titleHash) {
    const cachedBuffer = readFileSync(cacheFile);
    return new Response(cachedBuffer, {
      headers: {
        "Content-Type": "image/jpeg",
        "Cache-Control": "public, max-age=31536000, immutable",
      },
    });
  }

  const bg = await getBackground();

  const svg = await satori(textLayer(title) as any, {
    width: W,
    height: H,
    fonts: [
      { name: "Noto", data: fontBuffer, weight: 400, style: "normal" },
      { name: "Noto", data: fontBuffer, weight: 700, style: "normal" },
    ],
  });

  const pngBuffer = new Resvg(svg, { fitTo: { mode: "width", value: W } })
    .render()
    .asPng();

  // テキスト層を星空背景に重ねて JPEG で出力する
  const jpgBuffer = await sharp(bg)
    .composite([{ input: pngBuffer }])
    .jpeg({ quality: 88 })
    .toBuffer();

  // Save to cache in node_modules/.og-cache (persists across builds)
  if (!existsSync(cacheDir)) mkdirSync(cacheDir, { recursive: true });
  writeFileSync(cacheFile, jpgBuffer);
  cache[slug] = titleHash;
  writeFileSync(cacheJsonPath, JSON.stringify(cache, null, 2));

  return new Response(jpgBuffer, {
    headers: {
      "Content-Type": "image/jpeg",
      "Cache-Control": "public, max-age=31536000, immutable",
    },
  });
}