const { PATH_FILES } = require('../config')
const logger = require('../log/index')
const puppeteer = require('puppeteer');
const fs = require('fs')
const path = require('path')


// 生成
async function initBrowser () {
  logger.log.debug('启动', new Date().toLocaleString())
  return await puppeteer.launch({
    headless: true,
    args: ['--no-sandbox', '--disable-setuid-sandbox']
  });
}

let browser = null

function checkCache (fPath) {
  try {
    const fStat = fs.statSync(fPath)
    if (fStat) {
      const isFile = fStat.isFile()
      if (isFile) {
        return fPath
      }
    }
    return false
  } catch (err) {
    return false
  }
}

function wait(ms) {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      console.log("Done waiting");
      resolve(ms)
    }, ms)
  })
}

function asyncCheck(delay, step, delayFn) {
  return new Promise((resolve, reject) => {
    let attempts = 0;
    const maxAttempts = Math.ceil(delay / step); // 计算最大尝试次数

    const check = () => {
      delayFn().then(result => {
        if (result) {
          resolve({ result: true, type: 'check' });
        } else {
          attempts++;
          if (attempts > maxAttempts) {
            resolve({ result: false, type: 'max' });
          } else {
            // 如果还没有达到最大尝试次数，继续查询
            setTimeout(check, step);
          }
        }
      }).catch(error => {
        // 如果delayFn抛出错误，拒绝Promise
        logger.log.debug('检查页面状态失败', error)
        setTimeout(() => {
          resolve({ result: false, type: 'max-error' });
        }, delay)
      });
    };

    // 启动定时查询
    check();
  });
}



async function createPDFOfURL (url, config = {}) {
  if (!browser) {
    browser = await initBrowser()
  }
  config = Object.assign( {
    filename: '',
    dir: '',
    nocache: false,
    width: '950px',
    height: '1360px',
    margin: {
      top: 0,
      bottom: 0
    },
    step: 200,
    check: true
  }, config)
  // 文件路径
  const outPath = path.join(PATH_FILES, config.dir)
  if (!fs.existsSync(outPath)) {
    fs.mkdirSync(outPath);
  }
  const outConfig = Object.assign({path: `${config.filename}.pdf`, width: config.width, height: config.height,printBackground: true }, config)
  outConfig.path = path.join(outPath, outConfig.path)
  // 检查缓存
  if (!config.nocache) {
    const result = checkCache(outConfig.path)
    if (result) {
      logger.log.debug('命中缓存文件')
      return result
    }
  }
  const page = await browser.newPage();
  try {
    await page.setDefaultNavigationTimeout(0)
    await page.goto(url, {waitUntil: 'networkidle2'});
    logger.log.debug('等待生成', new Date().toLocaleString())

    if (config.check) {
      await asyncCheck(config.delay, config.step, async () => {
        const result = await page.evaluate(() => {
          return window.__PDF_LOADED__ || false
        })
        logger.log.debug('页面 __PDF_LOADED__ 状态检查', result)
        return result
      })
    } else {
      await wait(config.delay || 1000)
    }

    await page.pdf(outConfig);
    await page.close();

    logger.log.debug('当前时间', new Date().toLocaleString())
    return outConfig.path
  } catch (e) {
    logger.log.debug(e)
    await page.close();
  }
}

module.exports = createPDFOfURL