const fs = require('fs');
const path = require('path');
const readline = require('readline');
const logger = require('./logger');

function isEnabled(options = {}) {
  return options.debugTask === true || process.env.DEBUG_TASK === 'true';
}

function shouldKeepOpen(options = {}) {
  return options.keepOpen === true || process.env.DEBUG_KEEP_OPEN === 'true';
}

function shouldPauseEachStep(options = {}) {
  return options.pauseEachStep === true || process.env.DEBUG_PAUSE_EACH_STEP === 'true';
}

function isDryRun(options = {}) {
  return options.dryRun === true || process.env.DEBUG_DRY_RUN === 'true';
}

function createDebugRunDir(taskName) {
  const stamp = new Date().toISOString()
    .replace(/[:.]/g, '-')
    .replace('T', '_')
    .slice(0, 19);
  const safeName = String(taskName).replace(/[^\w.-]+/g, '_');
  const dir = path.resolve('debug-runs', `${stamp}_${safeName}`);
  fs.mkdirSync(dir, { recursive: true });
  return dir;
}

async function pageInfo(page) {
  if (!page || page.isClosed()) {
    return { title: '', url: '(page closed)' };
  }

  const title = await page.title().catch(() => '');
  const url = page.url();
  return { title, url };
}

async function saveFailureArtifacts(page, dir, index, stepName, err) {
  if (!dir || !page || page.isClosed()) return;

  const safeStep = String(stepName).replace(/[^\w.-]+/g, '_').slice(0, 80);
  const prefix = `${String(index).padStart(2, '0')}_${safeStep}`;

  await page.screenshot({
    path: path.join(dir, `${prefix}_fail.png`),
    fullPage: true,
  }).catch((screenshotErr) => {
    logger.warn(`  → 失败截图保存失败: ${screenshotErr.message}`);
  });

  const html = await page.content().catch(() => '');
  if (html) {
    fs.writeFileSync(path.join(dir, `${prefix}_fail.html`), html, 'utf-8');
  }

  fs.writeFileSync(
    path.join(dir, `${prefix}_error.txt`),
    err.stack || err.message,
    'utf-8'
  );
}

function formatInspectValue(value) {
  if (value === null || typeof value === 'undefined') return String(value);
  if (typeof value === 'string') return value;
  return JSON.stringify(value);
}

async function runInspect(step, ctx) {
  if (typeof step.inspect !== 'function') return;

  logger.info('元素检查:');
  try {
    const result = await step.inspect(ctx);
    if (!result || typeof result !== 'object') {
      logger.info(`  ${formatInspectValue(result)}`);
      return;
    }

    for (const [key, value] of Object.entries(result)) {
      logger.info(`  ${key}: ${formatInspectValue(value)}`);
    }
  } catch (err) {
    logger.warn(`  inspect 执行失败: ${err.message}`);
  }
}

function waitForEnter(message) {
  return new Promise((resolve) => {
    const rl = readline.createInterface({
      input: process.stdin,
      output: process.stdout,
    });
    rl.question(message, () => {
      rl.close();
      resolve();
    });
  });
}

async function runDebugSteps(taskName, steps, ctx = {}, options = {}) {
  const enabled = isEnabled(options);
  const debugOptions = {
    enabled,
    keepOpen: shouldKeepOpen(options),
    pauseEachStep: shouldPauseEachStep(options),
    dryRun: isDryRun(options),
    runDir: enabled ? createDebugRunDir(taskName) : '',
  };

  ctx.debug = debugOptions;

  if (enabled) {
    logger.divider();
    logger.info(`[DEBUG] 单任务调试: ${taskName}`);
    logger.info(`[DEBUG] 产物目录: ${debugOptions.runDir}`);
    logger.info(`[DEBUG] keepOpen=${debugOptions.keepOpen}, pauseEachStep=${debugOptions.pauseEachStep}, dryRun=${debugOptions.dryRun}`);
  }

  for (let i = 0; i < steps.length; i++) {
    const step = steps[i];
    const stepNo = i + 1;
    const label = `Step ${stepNo}/${steps.length}: ${step.name}`;

    if (enabled) {
      logger.info(`[DEBUG] ${label} 开始`);
    } else {
      logger.info(`  → ${step.name}`);
    }

    try {
      await step.run(ctx);

      if (enabled) {
        const info = await pageInfo(step.page ? step.page(ctx) : ctx.page);
        logger.info(`[DEBUG] ${label} ✅`);
        logger.info(`[DEBUG] 当前页面: ${info.url}`);
      }

      if (enabled && debugOptions.pauseEachStep) {
        await waitForEnter(`[DEBUG] ${label} 已完成，按 Enter 继续...`);
      }
    } catch (err) {
      logger.error(enabled ? `[DEBUG] ${label} ❌` : `${label} ❌`);
      logger.error(`错误: ${err.message}`);

      const activePage = step.page ? step.page(ctx) : (ctx.currentPage || ctx.page);
      const info = await pageInfo(activePage);
      logger.error(`当前页面: ${info.url}`);
      logger.error(`页面标题: ${info.title}`);

      await runInspect(step, ctx);
      await saveFailureArtifacts(activePage, debugOptions.runDir, stepNo, step.name, err);

      if (enabled && debugOptions.keepOpen) {
        logger.warn('浏览器已保留，请检查页面元素。');
        await waitForEnter('按 Enter 关闭浏览器并退出...');
      }

      throw err;
    }
  }
}

module.exports = {
  runDebugSteps,
  isDryRun,
};