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

/**
 * SESSION BROKER COVERAGE (H5 Session architecture Patch 2 / §5.7)
 *
 * Business code must not call userAuth session ownership helpers directly.
 * Use session-broker.mjs facade via createSessionAccess / resolveSessionAccess.
 *
 * See docs/h5-session-architecture-20260706.md §5.7
 */

/** @typedef {{ file: string, line: number, rule: string, text: string }} SessionBrokerCoverageViolation */

export const SESSION_BROKER_FACADE_FILE = 'session-broker.mjs';
export const SESSION_BROKER_DEFINITION_FILE = 'user-auth.mjs';

/** Files allowed to call userAuth.registerAgentSession / ownsSession directly. */
export const SESSION_BROKER_DIRECT_ALLOWLIST = new Set([
  SESSION_BROKER_FACADE_FILE,
  SESSION_BROKER_DEFINITION_FILE,
]);

/** Patch 2 modules that must route session ownership through sessionAccess. */
export const SESSION_BROKER_PATCH2_FILES = [
  'tkmind-proxy.mjs',
  'agent-run-routes.mjs',
  'agent-run-gateway.mjs',
  'direct-chat-service.mjs',
  'server.mjs',
  'wechat-mp.mjs',
  'mindspace-page-edit-session.mjs',
  'mindspace-agent-runner.mjs',
  'mindspace-conversation-package-routes.mjs',
];

export const SESSION_BROKER_FORBIDDEN_CALLS = [
  { id: 'register-agent-session', pattern: /\buserAuth\.registerAgentSession\s*\(/ },
  { id: 'owns-session', pattern: /\buserAuth\.ownsSession\s*\(/ },
  { id: 'get-session-target', pattern: /\buserAuth\.getSessionTarget\s*\(/ },
  { id: 'unregister-agent-session', pattern: /\buserAuth\.unregisterAgentSession\s*\(/ },
];

export const SESSION_BROKER_PATCH2_MARKERS = [
  /\bresolveSessionAccess\b/,
  /\bcreateSessionAccess\b/,
  /\bsessionAccess\b/,
];

export const SESSION_BROKER_SCAN_IGNORE = [
  /^scripts\//,
  /^mindspace-service\//,
  /^\.runtime\//,
  /^node_modules\//,
  /\.test\.mjs$/,
  /\.test\.ts$/,
];

export const SESSION_BROKER_LINE_ALLOW = [
  /SESSION BROKER COVERAGE/,
  /§5\.7/,
  /session-broker\.mjs/,
  /createSessionAccess/,
  /resolveSessionAccess/,
  /sessionAccess\./,
  /getSessionAccess/,
];

function relativePosix(rootDir, absolutePath) {
  return path.relative(rootDir, absolutePath).split(path.sep).join('/');
}

function isIgnoredScanPath(relativePath) {
  return SESSION_BROKER_SCAN_IGNORE.some((pattern) => pattern.test(relativePath));
}

function isTestFile(relativePath) {
  return /\.test\.mjs$/.test(relativePath);
}

function isLineAllowed(line) {
  return SESSION_BROKER_LINE_ALLOW.some((pattern) => pattern.test(line));
}

function scanDirectUserAuthCalls(relativePath, content) {
  /** @type {SessionBrokerCoverageViolation[]} */
  const violations = [];
  if (SESSION_BROKER_DIRECT_ALLOWLIST.has(relativePath) || isTestFile(relativePath)) {
    return violations;
  }

  const lines = content.split('\n');
  for (let index = 0; index < lines.length; index += 1) {
    const line = lines[index];
    if (!line.trim() || line.trim().startsWith('//') || line.trim().startsWith('*')) continue;
    if (isLineAllowed(line)) continue;
    for (const rule of SESSION_BROKER_FORBIDDEN_CALLS) {
      if (!rule.pattern.test(line)) continue;
      violations.push({
        file: relativePath,
        line: index + 1,
        rule: rule.id,
        text: line.trim(),
      });
    }
  }
  return violations;
}

function checkPatch2ModuleWiring(rootDir) {
  /** @type {SessionBrokerCoverageViolation[]} */
  const violations = [];
  for (const relativePath of SESSION_BROKER_PATCH2_FILES) {
    const absolutePath = path.join(rootDir, relativePath);
    if (!fs.existsSync(absolutePath)) {
      violations.push({
        file: relativePath,
        line: 0,
        rule: 'missing-patch2-file',
        text: 'Patch 2 module missing from repository',
      });
      continue;
    }
    const content = fs.readFileSync(absolutePath, 'utf8');
    if (!SESSION_BROKER_PATCH2_MARKERS.some((pattern) => pattern.test(content))) {
      violations.push({
        file: relativePath,
        line: 0,
        rule: 'missing-session-access-wiring',
        text: 'Expected resolveSessionAccess/createSessionAccess/sessionAccess wiring',
      });
    }
  }
  return violations;
}

export function checkSessionBrokerCoverage(rootDir, { scanRepo = true } = {}) {
  /** @type {SessionBrokerCoverageViolation[]} */
  const violations = [...checkPatch2ModuleWiring(rootDir)];

  if (!scanRepo) return violations;

  const queue = [rootDir];
  while (queue.length > 0) {
    const current = queue.pop();
    const entries = fs.readdirSync(current, { withFileTypes: true });
    for (const entry of entries) {
      if (entry.name === 'node_modules' || entry.name === '.git') continue;
      const absolutePath = path.join(current, entry.name);
      const relativePath = relativePosix(rootDir, absolutePath);
      if (entry.isDirectory()) {
        queue.push(absolutePath);
        continue;
      }
      if (!entry.name.endsWith('.mjs')) continue;
      if (isIgnoredScanPath(relativePath)) continue;
      const content = fs.readFileSync(absolutePath, 'utf8');
      violations.push(...scanDirectUserAuthCalls(relativePath, content));
    }
  }

  return violations;
}

export function formatSessionBrokerCoverageViolations(violations) {
  return violations
    .map((item) => `${item.file}:${item.line} [${item.rule}] ${item.text}`)
    .join('\n');
}