import { Buffer } from 'node:buffer';
import {
  existsSync,
  mkdirSync,
  readFileSync,
  writeFileSync,
} from 'node:fs';
import path from 'node:path';
import { fileURLToPath } from 'node:url';

const scriptDir = path.dirname(fileURLToPath(import.meta.url));
const repoRoot = path.resolve(scriptDir, '..');
const defaultOut = path.join(
  repoRoot,
  'public',
  'child-motion-demo',
  'picture-book-grass-stage.webp',
);
const defaultSize = '1536x1024';
const defaultTimeoutMs = 180000;

const prompt = [
  '请生成一张横版儿童动作互动游戏舞台背景图，卡通绘本风格，温暖明亮。',
  '画面下半部分必须是开阔柔软的草地地面，适合叠加半透明角色轮廓和地面圆圈指示环。',
  '远处有柔和小山坡、树木、天空和浅色云朵，中心和下方前景保持干净开阔。',
  '构图需要适配 16:9 横屏游戏舞台，左右和上下边缘可安全裁切，主体信息不要贴边。',
  '风格像儿童绘本插画，柔和笔触，清新色彩，轻微纸张纹理，细节适中，不杂乱。',
  '不要出现人物、动物、文字、按钮、UI、边框、水印、摄像头画面、真实照片质感。',
].join('');

const args = new Map();
for (let index = 2; index < process.argv.length; index += 1) {
  const raw = process.argv[index];
  if (!raw.startsWith('--')) {
    continue;
  }
  const next = process.argv[index + 1];
  if (next && !next.startsWith('--')) {
    args.set(raw, next);
    index += 1;
  } else {
    args.set(raw, true);
  }
}

function readDotenv(fileName) {
  const filePath = path.join(repoRoot, fileName);
  if (!existsSync(filePath)) {
    return {};
  }

  const values = {};
  for (const line of readFileSync(filePath, 'utf8').split(/\r?\n/u)) {
    const trimmed = line.trim();
    if (!trimmed || trimmed.startsWith('#')) {
      continue;
    }

    const match = /^([A-Za-z_][A-Za-z0-9_]*)=(.*)$/u.exec(trimmed);
    if (!match) {
      continue;
    }

    let value = match[2].trim();
    if (
      (value.startsWith('"') && value.endsWith('"')) ||
      (value.startsWith("'") && value.endsWith("'"))
    ) {
      value = value.slice(1, -1);
    }
    values[match[1]] = value;
  }
  return values;
}

function resolveEnv() {
  const loaded = {
    ...readDotenv('.env.example'),
    ...readDotenv('.env.local'),
    ...readDotenv('.env.secrets.local'),
    ...process.env,
  };
  return {
    baseUrl: String(loaded.VECTOR_ENGINE_BASE_URL || '')
      .trim()
      .replace(/\/+$/u, ''),
    apiKey: String(loaded.VECTOR_ENGINE_API_KEY || '').trim(),
    timeoutMs: Number.parseInt(
      String(loaded.VECTOR_ENGINE_IMAGE_REQUEST_TIMEOUT_MS || defaultTimeoutMs),
      10,
    ),
  };
}

function buildVectorEngineImagesGenerationUrl(baseUrl) {
  return baseUrl.endsWith('/v1')
    ? `${baseUrl}/images/generations`
    : `${baseUrl}/v1/images/generations`;
}

function collectStringsByKey(value, targetKey, output) {
  if (Array.isArray(value)) {
    value.forEach((entry) => collectStringsByKey(entry, targetKey, output));
    return;
  }
  if (!value || typeof value !== 'object') {
    return;
  }

  for (const [key, nested] of Object.entries(value)) {
    if (key === targetKey) {
      if (typeof nested === 'string' && nested.trim()) {
        output.push(nested.trim());
      }
      if (Array.isArray(nested)) {
        nested.forEach((entry) => {
          if (typeof entry === 'string' && entry.trim()) {
            output.push(entry.trim());
          }
        });
      }
    }
    collectStringsByKey(nested, targetKey, output);
  }
}

function extractImageUrls(payload) {
  const urls = [];
  collectStringsByKey(payload, 'url', urls);
  collectStringsByKey(payload, 'image', urls);
  collectStringsByKey(payload, 'image_url', urls);
  return [...new Set(urls)].filter((url) => /^https?:\/\//u.test(url));
}

function extractBase64Images(payload) {
  const values = [];
  collectStringsByKey(payload, 'b64_json', values);
  return values;
}

async function fetchWithTimeout(url, options, timeoutMs) {
  const abortController = new AbortController();
  const timer = setTimeout(() => abortController.abort(), timeoutMs);
  try {
    const response = await fetch(url, {
      ...options,
      signal: abortController.signal,
    });
    const text = await response.text();
    if (!response.ok) {
      throw new Error(`VectorEngine ${response.status}: ${text.slice(0, 600)}`);
    }
    return text;
  } catch (error) {
    if (error?.name === 'AbortError') {
      throw new Error(`VectorEngine request timed out after ${timeoutMs}ms`);
    }
    throw error;
  } finally {
    clearTimeout(timer);
  }
}

async function downloadImage(url, timeoutMs) {
  const abortController = new AbortController();
  const timer = setTimeout(() => abortController.abort(), timeoutMs);
  try {
    const response = await fetch(url, { signal: abortController.signal });
    if (!response.ok) {
      throw new Error(`download ${response.status}`);
    }
    return Buffer.from(await response.arrayBuffer());
  } catch (error) {
    if (error?.name === 'AbortError') {
      throw new Error(`Generated image download timed out after ${timeoutMs}ms`);
    }
    throw error;
  } finally {
    clearTimeout(timer);
  }
}

const size = String(args.get('--size') || defaultSize);
const outPath = path.resolve(String(args.get('--out') || defaultOut));
const requestBody = {
  model: 'gpt-image-2-all',
  prompt,
  n: 1,
  size,
};

if (args.has('--dry-run') || !args.has('--live')) {
  console.log(
    JSON.stringify(
      {
        mode: 'dry-run',
        outPath,
        body: requestBody,
      },
      null,
      2,
    ),
  );
  process.exit(0);
}

const env = resolveEnv();
if (!env.baseUrl || !env.apiKey) {
  console.error(
    JSON.stringify({
      ok: false,
      error: 'Missing VECTOR_ENGINE_BASE_URL or VECTOR_ENGINE_API_KEY',
      hasBaseUrl: Boolean(env.baseUrl),
      hasApiKey: Boolean(env.apiKey),
    }),
  );
  process.exit(1);
}

const payloadText = await fetchWithTimeout(
  buildVectorEngineImagesGenerationUrl(env.baseUrl),
  {
    method: 'POST',
    headers: {
      Authorization: `Bearer ${env.apiKey}`,
      Accept: 'application/json',
      'Content-Type': 'application/json',
    },
    body: JSON.stringify(requestBody),
  },
  env.timeoutMs,
);

const payload = JSON.parse(payloadText);
const urls = extractImageUrls(payload);
const base64Images = extractBase64Images(payload);
const imageBytes = urls[0]
  ? await downloadImage(urls[0], env.timeoutMs)
  : base64Images[0]
    ? Buffer.from(base64Images[0], 'base64')
    : null;

if (!imageBytes) {
  throw new Error('VectorEngine returned no image');
}

mkdirSync(path.dirname(outPath), { recursive: true });
writeFileSync(outPath, imageBytes);

console.log(
  JSON.stringify(
    {
      ok: true,
      file: outPath,
      size,
      source: urls[0] ? 'url' : 'b64_json',
    },
    null,
    2,
  ),
);