import http from "node:http";
import fs from "node:fs/promises";
import path from "node:path";
import crypto from "node:crypto";
import { spawn } from "node:child_process";
import { fileURLToPath } from "node:url";

const PORT = Number(process.env.PORT || 7860);
const ROOT = path.dirname(fileURLToPath(import.meta.url));
const WORK = path.join(ROOT, "work");
const jobs = new Map();
const MAX_BYTES = 250 * 1024 * 1024;

const R2_ACCOUNT_ID = process.env.R2_ACCOUNT_ID || "";
const R2_BUCKET = process.env.R2_BUCKET || "";
const R2_ACCESS_KEY_ID = process.env.R2_ACCESS_KEY_ID || "";
const R2_SECRET_ACCESS_KEY = process.env.R2_SECRET_ACCESS_KEY || "";
const R2_PUBLIC_BASE_URL = process.env.R2_PUBLIC_BASE_URL || "";
const R2_REGION = "auto";
const R2_SERVICE = "s3";

function r2Configured() {
  return Boolean(R2_ACCOUNT_ID && R2_BUCKET && R2_ACCESS_KEY_ID && R2_SECRET_ACCESS_KEY && R2_PUBLIC_BASE_URL);
}

function encodeRfc3986(value) {
  return encodeURIComponent(value).replace(/[!'()*]/g, char => "%" + char.charCodeAt(0).toString(16).toUpperCase());
}

function encodePath(value) {
  return value.split("/").map(encodeRfc3986).join("/");
}

function canonicalQueryString(params) {
  return Object.keys(params).sort().map(key => encodeRfc3986(key) + "=" + encodeRfc3986(params[key])).join("&");
}

function sha256Hex(value) {
  return crypto.createHash("sha256").update(value, "utf8").digest("hex");
}

function hmac(key, value) {
  return crypto.createHmac("sha256", key).update(value, "utf8").digest();
}

function hmacHex(key, value) {
  return crypto.createHmac("sha256", key).update(value, "utf8").digest("hex");
}

function getSignatureKey(secret, dateStamp) {
  const kDate = hmac("AWS4" + secret, dateStamp);
  const kRegion = hmac(kDate, R2_REGION);
  const kService = hmac(kRegion, R2_SERVICE);
  return hmac(kService, "aws4_request");
}

function toAmzDate(date) {
  return date.toISOString().replace(/[:-]|\.\d{3}/g, "").slice(0, 15) + "Z";
}

function buildR2PresignedPutUrl(key, contentType) {
  if (!r2Configured()) throw new Error("R2 secrets are not configured");
  const now = new Date();
  const host = R2_ACCOUNT_ID + ".r2.cloudflarestorage.com";
  const amzDate = toAmzDate(now);
  const dateStamp = amzDate.slice(0, 8);
  const credentialScope = dateStamp + "/" + R2_REGION + "/" + R2_SERVICE + "/aws4_request";
  const canonicalUri = "/" + encodePath(R2_BUCKET) + "/" + encodePath(key);
  const signedHeaders = "content-type;host";
  const query = {
    "X-Amz-Algorithm": "AWS4-HMAC-SHA256",
    "X-Amz-Credential": R2_ACCESS_KEY_ID + "/" + credentialScope,
    "X-Amz-Date": amzDate,
    "X-Amz-Expires": "600",
    "X-Amz-SignedHeaders": signedHeaders
  };
  const canonicalQuery = canonicalQueryString(query);
  const canonicalHeaders = "content-type:" + contentType.trim().replace(/\s+/g, " ") + "\n" + "host:" + host + "\n";
  const canonicalRequest = ["PUT", canonicalUri, canonicalQuery, canonicalHeaders, signedHeaders, "UNSIGNED-PAYLOAD"].join("\n");
  const stringToSign = ["AWS4-HMAC-SHA256", amzDate, credentialScope, sha256Hex(canonicalRequest)].join("\n");
  const signature = hmacHex(getSignatureKey(R2_SECRET_ACCESS_KEY, dateStamp), stringToSign);
  return "https://" + host + canonicalUri + "?" + canonicalQuery + "&X-Amz-Signature=" + signature;
}

function r2PublicUrl(key) {
  return R2_PUBLIC_BASE_URL.replace(/\/+$/, "") + "/" + encodePath(key);
}

async function uploadToR2(file, key) {
  const contentType = "model/gltf-binary";
  const data = await fs.readFile(file);
  const uploadUrl = buildR2PresignedPutUrl(key, contentType);
  const response = await fetch(uploadUrl, {
    method: "PUT",
    headers: { "content-type": contentType },
    body: data,
    signal: AbortSignal.timeout(180000)
  });
  if (!response.ok) throw new Error("R2 upload failed: HTTP " + response.status + " " + (await response.text()).slice(0, 1000));
  return {key, url: r2PublicUrl(key), bytes: data.length};
}


await fs.mkdir(WORK, { recursive: true });

function json(res, status, body) {
  const data = Buffer.from(JSON.stringify(body));
  res.writeHead(status, {
    "content-type": "application/json; charset=utf-8",
    "content-length": data.length
  });
  res.end(data);
}

function readBody(req) {
  return new Promise((resolve, reject) => {
    const chunks = [];
    let size = 0;
    req.on("data", chunk => {
      size += chunk.length;
      if (size > 1024 * 1024) {
        reject(new Error("request too large"));
        req.destroy();
        return;
      }
      chunks.push(chunk);
    });
    req.on("end", () => resolve(Buffer.concat(chunks).toString("utf8")));
    req.on("error", reject);
  });
}

function safeUrl(value) {
  try {
    const parsed = new URL(value);
    return parsed.protocol === "https:" || parsed.protocol === "http:";
  } catch {
    return false;
  }
}

async function download(url, target) {
  const response = await fetch(url, {
    signal: AbortSignal.timeout(180000),
    headers: { "user-agent": "Machesta-GLB-Optimizer/1.0" }
  });
  if (!response.ok) throw new Error("download failed: HTTP " + response.status);
  const declared = Number(response.headers.get("content-length") || 0);
  if (declared > MAX_BYTES) throw new Error("input GLB exceeds size limit");
  const buffer = Buffer.from(await response.arrayBuffer());
  if (buffer.length > MAX_BYTES) throw new Error("input GLB exceeds size limit");
  await fs.writeFile(target, buffer);
  return buffer.length;
}

function runOptimize(input, output) {
  return new Promise((resolve, reject) => {
    const args = [
      "gltf-transform", "optimize", input, output,
      "--compress", "draco",
      "--texture-compress", "webp",
      "--texture-size", "512",
      "--simplify-ratio", "0.3",
      "--simplify-error", "0.001"
    ];
    const child = spawn("npx", ["--yes", ...args], {
      cwd: ROOT,
      stdio: ["ignore", "pipe", "pipe"]
    });
    let logs = "";
    child.stdout.on("data", data => { logs += data.toString(); });
    child.stderr.on("data", data => { logs += data.toString(); });
    child.on("error", reject);
    child.on("close", code => {
      if (code === 0) resolve(logs.slice(-12000));
      else reject(new Error("optimizer exited with code " + code + ": " + logs.slice(-4000)));
    });
  });
}

async function processJob(job) {
  job.status = "processing";
  const input = path.join(WORK, job.id + "-input.glb");
  const output = path.join(WORK, job.id + "-mobile.glb");
  try {
    job.inputBytes = await download(job.url, input);
    await runOptimize(input, output);
    const stat = await fs.stat(output);
    if (stat.size === 0) throw new Error("optimizer produced an empty file");
    job.outputBytes = stat.size;
    const r2Key = "optimized-glb/" + job.id + ".glb";
    const uploaded = await uploadToR2(output, r2Key);
    job.r2Key = uploaded.key;
    job.r2Url = uploaded.url;
    job.status = "ready";
    job.downloadPath = uploaded.url;
  } catch (error) {
    job.status = "failed";
    job.error = error instanceof Error ? error.message : String(error);
  } finally {
    await fs.rm(input, { force: true }).catch(() => {});
    if (job.status !== "ready") await fs.rm(output, { force: true }).catch(() => {});
  }
}

const server = http.createServer(async (req, res) => {
  const url = new URL(req.url || "/", "http://" + (req.headers.host || "localhost"));

  if (req.method === "GET" && url.pathname === "/health") {
    return json(res, 200, { ok: true, service: "machesta-glb-optimizer", optimizer: "gltf-transform-draco", r2Configured: r2Configured() });
  }

  if (req.method === "POST" && url.pathname === "/optimize") {
    try {
      const body = JSON.parse(await readBody(req));
      if (!safeUrl(body.url)) return json(res, 400, { error: "url must be http or https" });
      const id = crypto.randomUUID();
      const job = { id: id, url: body.url, status: "queued", createdAt: new Date().toISOString() };
      jobs.set(id, job);
      processJob(job);
      return json(res, 202, { jobId: id, status: job.status, statusUrl: "/jobs/" + id });
    } catch (error) {
      return json(res, 400, { error: error instanceof Error ? error.message : String(error) });
    }
  }

  const jobMatch = url.pathname.match(/^\/jobs\/([a-f0-9-]+)$/);
  if (req.method === "GET" && jobMatch) {
    const job = jobs.get(jobMatch[1]);
    return job ? json(res, 200, job) : json(res, 404, { error: "job not found" });
  }

  const downloadMatch = url.pathname.match(/^\/download\/([a-f0-9-]+)$/);
  if (req.method === "GET" && downloadMatch) {
    const job = jobs.get(downloadMatch[1]);
    if (!job || job.status !== "ready") return json(res, 404, { error: "optimized file not ready" });
    const file = path.join(WORK, job.id + "-mobile.glb");
    try {
      const data = await fs.readFile(file);
      res.writeHead(200, {
        "content-type": "model/gltf-binary",
        "content-disposition": "attachment; filename=\"" + job.id + "-mobile.glb\"",
        "content-length": data.length
      });
      return res.end(data);
    } catch {
      return json(res, 404, { error: "optimized file expired or unavailable" });
    }
  }

  return json(res, 404, { error: "not found" });
});

server.listen(PORT, "0.0.0.0", () => {
  console.log("Machesta GLB optimizer listening on " + PORT);
});