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

const root = process.cwd();
const contract = JSON.parse(fs.readFileSync(path.join(root, 'docs/contracts/client-shared-styles-r11.json'), 'utf8'));
const read = (file) => fs.readFileSync(path.join(root, file), 'utf8');
const failures = [];
const style = read(contract.styleFile);
const globalStyle = read(contract.globalStyleFile);
const entry = read(contract.entryFile);
const styleTree = postcss.parse(style);

const listFiles = (directory, extensions) => {
  const result = [];
  const visit = (current) => {
    for (const item of fs.readdirSync(current, { withFileTypes: true })) {
      const absolute = path.join(current, item.name);
      if (item.isDirectory()) visit(absolute);
      else if (extensions.some((extension) => item.name.endsWith(extension))) result.push(absolute);
    }
  };
  visit(path.join(root, directory));
  return result;
};

const clientFiles = listFiles('src/apps/client', ['.ts', '.tsx']);
const adminFiles = listFiles('src/apps/admin', ['.ts', '.tsx']);
const countUsage = (files, className) => files.filter((file) => fs.readFileSync(file, 'utf8').includes(className)).length;
const selectorClasses = (selector) => [...selector.matchAll(/\.([_a-zA-Z]+[\w-]*)/g)].map((match) => match[1]);

if (!style.includes(contract.marker)) failures.push(`${contract.styleFile} is missing its ownership marker`);

const importOrder = [
  "@/styles/tokens.css",
  "@/styles/reset.css",
  "@/styles/shell.css",
  "@/styles/global.css",
  "@/styles/admin.css",
  "@/styles/client.css",
  "@/styles/components.css",
];
let previousIndex = -1;
for (const importPath of importOrder) {
  const index = entry.indexOf(`import '${importPath}';`);
  if (index < 0) failures.push(`${contract.entryFile} is missing ${importPath}`);
  if (index <= previousIndex) failures.push(`${contract.entryFile} has an invalid style import order at ${importPath}`);
  previousIndex = index;
}
if (entry.indexOf("import { AppRoutes }") <= previousIndex) {
  failures.push('AppRoutes must load after the complete shared style dependency chain');
}

let ruleCount = 0;
let selectorCount = 0;
styleTree.walkRules((rule) => {
  ruleCount += 1;
  for (const selector of rule.selectors ?? [rule.selector]) {
    selectorCount += 1;
    const classes = selectorClasses(selector);
    if (classes.length === 0 || !classes.every((className) => contract.ownedClasses.includes(className))) {
      failures.push(`${contract.styleFile} contains a non-client-shared selector: ${selector}`);
    }
  }
});
if (ruleCount < contract.minimumRuleCount) failures.push(`${contract.styleFile} has ${ruleCount} rules; minimum is ${contract.minimumRuleCount}`);
if (selectorCount < contract.minimumSelectorCount) failures.push(`${contract.styleFile} has ${selectorCount} selectors; minimum is ${contract.minimumSelectorCount}`);

for (const [className, minimumFiles] of Object.entries(contract.usageRequirements)) {
  const clientCount = countUsage(clientFiles, className);
  const adminCount = countUsage(adminFiles, className);
  if (clientCount < minimumFiles) failures.push(`${className} is used by ${clientCount} client files; minimum is ${minimumFiles}`);
  if (adminCount !== 0) failures.push(`${className} is unexpectedly used by ${adminCount} admin files`);
  const pureSelector = new RegExp(`^\\s*\\.${className}\\s*\\{`, 'm');
  if (pureSelector.test(globalStyle)) failures.push(`${contract.globalStyleFile} still owns .${className}`);
}

for (const selector of contract.requiredGlobalContextSelectors) {
  if (!globalStyle.includes(selector)) failures.push(`${contract.globalStyleFile} lost contextual override ${selector}`);
}

for (const [className, requirement] of Object.entries(contract.crossPortalClassesKeptGlobal)) {
  if (!globalStyle.includes(`.${className}`)) failures.push(`${contract.globalStyleFile} lost cross-portal class .${className}`);
  const clientCount = countUsage(clientFiles, className);
  const adminCount = countUsage(adminFiles, className);
  if (clientCount < requirement.minimumClientFiles) failures.push(`${className} client usage dropped to ${clientCount}`);
  if (adminCount < requirement.minimumAdminFiles) failures.push(`${className} admin usage dropped to ${adminCount}`);
}

for (const className of contract.singlePageClassesKeptGlobal) {
  if (!globalStyle.includes(`.${className}`)) failures.push(`${contract.globalStyleFile} lost single-page class .${className}`);
}

if (failures.length > 0) {
  console.error(`R11 client shared styles verification failed:\n- ${failures.join('\n- ')}`);
  process.exit(1);
}

console.log(
  `R11 client shared styles verified: ${ruleCount} rule, ${selectorCount} selector, `
  + `${Object.keys(contract.crossPortalClassesKeptGlobal).length} cross-portal boundaries and single-page ownership are preserved.`,
);