import fs from 'node:fs';
import path from 'node:path';
import process from 'node:process';

const repoRoot = process.cwd();
const defaultRoot = path.join(repoRoot, 'apps', 'taro', 'src');

const allowedPillRadiusSelectors = [
  'avatar',
  'progress',
  'track',
  'fill',
  'chip',
  'badge',
  'tag',
  'pill',
  'meta',
  'option-prefix',
  'watermark',
  'scrollbar',
  'thumb',
  'dot',
  '::before',
  '::after',
];

const allowedLinearGradientSelectors = [
  'body',
  'page',
  'layout',
  'student-page',
  'admin-page',
  'platform-page',
  'bootstrap-page',
  'header',
  'hero',
  'band',
  'surface',
  'module',
  'tone-',
  'button.primary',
  'primary-button',
  'avatar',
  'profile-avatar',
  'avatar-choice-icon',
  'brand-icon',
  'shell::after',
  'mini-avatar',
  'sidebar-user-tag',
  'form',
  'panel',
  'revealed',
  'trend',
  'points',
  'nested',
  'asset-watermark',
];

const allowedBackdropBlurSelectors = [
  'sidebar',
  'mobile-dock',
  'mobile-nav',
];

function parseArgs(argv) {
  const options = {
    root: defaultRoot,
    json: false,
  };
  for (let index = 0; index < argv.length; index += 1) {
    const arg = argv[index];
    if (arg === '--json') options.json = true;
    else if (arg === '--root') {
      options.root = path.resolve(repoRoot, argv[index + 1] || '');
      index += 1;
    } else if (arg.startsWith('--root=')) {
      options.root = path.resolve(repoRoot, arg.slice('--root='.length));
    }
  }
  return options;
}

function normalizeSlashes(value) {
  return value.replace(/\\/g, '/');
}

function relative(filePath) {
  return normalizeSlashes(path.relative(repoRoot, filePath));
}

function readText(filePath) {
  return fs.readFileSync(filePath, 'utf8').replace(/\r\n/g, '\n');
}

function walkCssFiles(dir) {
  if (!fs.existsSync(dir)) return [];
  const result = [];
  for (const entry of fs.readdirSync(dir, { withFileTypes: true })) {
    const entryPath = path.join(dir, entry.name);
    if (entry.isDirectory()) result.push(...walkCssFiles(entryPath));
    else if (entry.name.endsWith('.css')) result.push(entryPath);
  }
  return result.sort((a, b) => relative(a).localeCompare(relative(b)));
}

function createCollector() {
  const checks = [];
  function push(status, id, message, details = {}) {
    checks.push({ status, id, message, details });
  }
  return {
    checks,
    pass: (id, message, details) => push('pass', id, message, details),
    fail: (id, message, details) => push('fail', id, message, details),
  };
}

function summarize(checks, scannedFiles) {
  return checks.reduce(
    (summary, item) => {
      summary[item.status] += 1;
      return summary;
    },
    { fail: 0, pass: 0, scannedFiles },
  );
}

function lineNumber(text, index) {
  return text.slice(0, index).split('\n').length;
}

function selectorBefore(text, index) {
  const before = text.slice(0, index);
  const open = before.lastIndexOf('{');
  const close = before.lastIndexOf('}');
  if (open <= close) return '';
  const selectorStart = before.lastIndexOf('}', open - 1);
  return before.slice(selectorStart + 1, open).trim().replace(/\s+/g, ' ');
}

function selectorMatches(selector, tokens) {
  const normalized = selector.toLowerCase();
  return tokens.some(token => normalized.includes(token));
}

function collectBorderRadiusViolations(files) {
  const violations = [];
  const radiusPattern = /border-radius\s*:\s*([^;]+);/gi;
  for (const filePath of files) {
    const text = readText(filePath);
    for (const match of text.matchAll(radiusPattern)) {
      const value = match[1].trim();
      const selector = selectorBefore(text, match.index || 0);
      if (/999px/.test(value)) {
        if (!selectorMatches(selector, allowedPillRadiusSelectors)) {
          violations.push({
            file: relative(filePath),
            line: lineNumber(text, match.index || 0),
            selector,
            value,
            reason: '999px radius is reserved for progress bars, chips, badges and similar pill controls.',
          });
        }
        continue;
      }
      const pxValues = [...value.matchAll(/([0-9]+(?:\.[0-9]+)?)px/g)].map(item => Number(item[1]));
      const tooLarge = pxValues.filter(item => item > 32);
      if (tooLarge.length) {
        violations.push({
          file: relative(filePath),
          line: lineNumber(text, match.index || 0),
          selector,
          value,
          reason: 'Legacy question-bank cards, panels and buttons should stay within the 8-32px rounded scale.',
        });
      }
    }
  }
  return violations;
}

function collectPatternViolations(files, pattern, reason, allow = () => false) {
  const violations = [];
  for (const filePath of files) {
    const text = readText(filePath);
    for (const match of text.matchAll(pattern)) {
      const selector = selectorBefore(text, match.index || 0);
      if (allow(selector, match, text, filePath)) continue;
      violations.push({
        file: relative(filePath),
        line: lineNumber(text, match.index || 0),
        selector,
        value: match[0].trim(),
        reason,
      });
    }
  }
  return violations;
}

function emitCheck(collector, id, message, violations) {
  if (violations.length) collector.fail(id, message, { violations: violations.slice(0, 30), count: violations.length });
  else collector.pass(id, message);
}

function main() {
  const options = parseArgs(process.argv.slice(2));
  const files = walkCssFiles(options.root);
  const collector = createCollector();

  emitCheck(
    collector,
    'css.border_radius',
    'Taro CSS keeps legacy radii within the old question-bank rounded scale',
    collectBorderRadiusViolations(files),
  );
  emitCheck(
    collector,
    'css.viewport_font_size',
    'Taro CSS does not scale font-size with viewport units',
    collectPatternViolations(files, /font-size\s*:\s*[^;]*(?:vw|vh|vmin|vmax)[^;]*;/gi, 'Use fixed px/rpx-like sizing, not viewport-scaled font sizes.'),
  );
  emitCheck(
    collector,
    'css.letter_spacing',
    'Taro CSS does not use negative letter spacing',
    collectPatternViolations(files, /letter-spacing\s*:\s*-\s*[^;]+;/gi, 'Letter spacing must be 0 or positive.'),
  );
  emitCheck(
    collector,
    'css.decorative_effects',
    'Taro CSS uses only legacy-approved grid, banner, module and state gradients',
    [
      ...collectPatternViolations(files, /radial-gradient\s*\(/gi, 'Do not add decorative radial/orb gradients.'),
      ...collectPatternViolations(
        files,
        /(^|[;\s{])filter\s*:\s*[^;]*blur\s*\(/gi,
        'Do not add raw blurred decorative backgrounds; use scoped backdrop-filter only for legacy glass navigation.',
      ),
      ...collectPatternViolations(
        files,
        /backdrop-filter\s*:\s*[^;]*blur\s*\(/gi,
        'Backdrop blur is only allowed for legacy glass navigation surfaces.',
        selector => selectorMatches(selector, allowedBackdropBlurSelectors),
      ),
      ...collectPatternViolations(
        files,
        /linear-gradient\s*\(/gi,
        'Linear gradients must be scoped to legacy grid backgrounds, blue banners, module cards, primary actions or state panels.',
        selector => selectorMatches(selector, allowedLinearGradientSelectors),
      ),
    ],
  );
  emitCheck(
    collector,
    'css.pill_radius_scope',
    '999px radius is scoped to progress, chips, badges, avatars, scrollbars and decorative legacy markers',
    collectBorderRadiusViolations(files).filter(item => item.value.includes('999px')),
  );

  const payload = {
    summary: summarize(collector.checks, files.length),
    root: relative(options.root),
    checks: collector.checks,
  };
  if (options.json) {
    console.log(JSON.stringify(payload, null, 2));
  } else {
    console.log(`Taro visual guardrails: ${payload.summary.fail} fail(s), ${payload.summary.pass} pass(es), ${payload.summary.scannedFiles} file(s) scanned`);
    for (const item of collector.checks) {
      const marker = item.status === 'fail' ? 'FAIL' : 'PASS';
      console.log(`[${marker}] ${item.id}: ${item.message}`);
    }
  }
  if (payload.summary.fail > 0) process.exitCode = 1;
}

main();