import { spawn } from 'node:child_process';
import {
  accessSync,
  closeSync,
  constants,
  existsSync,
  fstatSync,
  lstatSync,
  type Stats,
  openSync,
  readSync,
  realpathSync,
  statSync,
} from 'node:fs';
import { basename, dirname, join, isAbsolute, delimiter, resolve } from 'node:path';
import { redactFindingSpans } from '../redact-engine';
import { CsoError, MAX_OUTPUT } from './contracts';

const SOURCE_RUNTIME = /^bun(?:\.exe)?$/i.test(basename(process.execPath));
const WINDOWS_GIT =
  process.platform === 'win32'
    ? process.env.GSTACK_CSO_TRUSTED_GIT || (SOURCE_RUNTIME ? (Bun.which('git') ?? '') : '')
    : '';
const WINDOWS_SYSTEM =
  process.platform === 'win32' ? join(process.env.SystemRoot || 'C:\\Windows', 'System32') : '';
export const TRUSTED_DIRECTORIES =
  process.platform === 'win32'
    ? [...new Set([WINDOWS_GIT ? dirname(WINDOWS_GIT) : '', WINDOWS_SYSTEM].filter(Boolean))]
    : ['/usr/local/bin', '/usr/bin', '/bin', '/opt/homebrew/bin', '/usr/local/sbin', '/usr/sbin', '/sbin'];
export const TRUSTED_PATH = TRUSTED_DIRECTORIES.join(delimiter);
export function executable(name: string): string {
  // Never consult the audited repository's PATH or executable overrides.
  if (!/^[a-zA-Z0-9._-]+$/.test(name)) throw new CsoError('INVALID_ARGUMENT', 'Invalid executable name');
  if (process.platform === 'win32' && name.toLowerCase() === 'git') {
    try {
      if (!WINDOWS_GIT || !isAbsolute(WINDOWS_GIT) || basename(WINDOWS_GIT).toLowerCase() !== 'git.exe')
        throw new Error();
      const stat = statSync(WINDOWS_GIT);
      if (!stat.isFile()) throw new Error();
      return realpathSync(WINDOWS_GIT);
    } catch {
      throw new CsoError(
        'TOOL_UNAVAILABLE',
        'git.exe is not the trusted executable bound during gstack setup',
      );
    }
  }
  for (const directory of TRUSTED_DIRECTORIES) {
    const candidates =
      process.platform === 'win32'
        ? [join(directory, `${name}.exe`), join(directory, `${name}.cmd`), join(directory, name)]
        : [join(directory, name)];
    for (const p of candidates) {
      try {
        const stat = statSync(p);
        accessSync(p, constants.X_OK);
        if (stat.isFile() && (process.platform === 'win32' || stat.mode & 0o111)) return realpathSync(p);
      } catch {}
    }
  }
  throw new CsoError('TOOL_UNAVAILABLE', `${name} is not installed in a trusted system executable directory`);
}
export function childEnvironment(home: string): Record<string, string> {
  return {
    PATH: TRUSTED_PATH,
    HOME: home,
    LANG: 'C.UTF-8',
    LC_ALL: 'C.UTF-8',
    TZ: 'UTC',
    GIT_CONFIG_NOSYSTEM: '1',
    GIT_CONFIG_GLOBAL: process.platform === 'win32' ? 'NUL' : '/dev/null',
    GIT_TERMINAL_PROMPT: '0',
    GIT_OPTIONAL_LOCKS: '0',
    GIT_ATTR_NOSYSTEM: '1',
  };
}
export function redact(value: string): string {
  // Scan the complete bounded stream, including across write/chunk boundaries.
  const output = redactFindingSpans(value, { maxBytes: MAX_OUTPUT });
  if (output === null)
    throw new CsoError(
      'REDACTION_FAILED',
      'Payload withheld because redaction could not safely locate every secret',
    );
  return output;
}
const HASH_KEYS = new Set([
  'planSha256',
  'planHash',
  'originalHash',
  'executionHash',
  'snapshotHash',
  'sourceHash',
  'beforeSha256',
  'afterSha256',
  'patchHash',
  'reviewedPatchHash',
  'harnessHash',
  'fixturesHash',
  'policyHash',
  'auditPolicyHash',
  'originalSourceHash',
  'transformationsHash',
  'archivesHash',
  'inputHash',
  'beforeSourceHash',
  'afterSourceHash',
  'beforeDependencies',
  'afterDependencies',
  'beforeConfiguration',
  'afterConfiguration',
  'requestHash',
  'startPlanHash',
  'testPlanHash',
  'preparationHash',
  'preparedManifestHash',
  'preparedDependencyHash',
  'sourceProjectionHash',
  'executionEnvironmentHash',
  'databaseHash',
  'receiptHash',
  'dependencyClosureHash',
  'closureHash',
  'acquisitionReceiptHash',
  'registryResponseSha256',
  'sha256',
  'versionOutputSha256',
  'isolationPolicyHash',
  'contentSha256',
  'sbomDigest',
  'provenanceDigest',
  'dependencyHash',
  'configurationHash',
  'assertionHash',
  'commandsHash',
  'minimumPassingTestsHash',
  'commandHash',
  'outputHash',
  'observationHash',
  'witnessHash',
  'keyId',
]);
function safeMetadata(value: string, key: string): boolean {
  if (HASH_KEYS.has(key) && /^[a-f0-9]{64}$/.test(value)) return true;
  if (
    [
      'id',
      'fingerprint',
      'findingId',
      'verificationId',
      'reproductionAttemptId',
      'artifactId',
      'reviewArtifactId',
      'bundleId',
      'pathId',
    ].includes(key) &&
    /^[a-f0-9]{32}$/.test(value)
  )
    return true;
  if (key === 'path' && /^@cso-path\/\/[a-f0-9]{32}$/.test(value)) return true;
  if (key === 'repoId' && /^[a-f0-9]{24}$/.test(value)) return true;
  if (key === 'runId' && /^\d{13}-[a-f0-9]{16}$/.test(value)) return true;
  if (key === 'replayId' && /^\d{13}-[a-f0-9]{16}$/.test(value)) return true;
  if (['baseCommit', 'headCommit'].includes(key) && /^[a-f0-9]{40,64}$/.test(value)) return true;
  if (
    ['createdAt', 'expiresAt', 'deadline', 'at', 'databaseUpdatedAt', 'qualifiedAt'].includes(key) &&
    /^\d{4}-\d\d-\d\dT\d\d:\d\d:\d\d(?:\.\d{3})?Z$/.test(value)
  )
    return true;
  if (key === 'nonce' && /^[a-f0-9]{64}$/.test(value)) return true;
  if (key === 'publicKey' && /^[a-f0-9]{88}$/.test(value)) return true;
  if (key === 'signature' && /^[a-f0-9]{128}$/.test(value)) return true;
  if (key === 'image' && /^[a-z0-9./:_-]+@sha256:[a-f0-9]{64}$/.test(value)) return true;
  if (key === 'integrity' && /^(?:sha256|sha512)-[A-Za-z0-9+/]+={0,2}$/.test(value)) return true;
  return false;
}
function sanitizeJson(value: unknown, key: string, seen: WeakSet<object>, trustedMetadata: boolean): unknown {
  if (typeof value === 'string') {
    if (trustedMetadata && safeMetadata(value, key)) return value;
    return redact(value);
  }
  if (value === null || typeof value !== 'object') return value;
  if (seen.has(value as object)) throw new CsoError('INVALID_SCHEMA', 'Cyclic JSON cannot be persisted');
  seen.add(value as object);
  if (Array.isArray(value)) {
    const out = value.map((v) => sanitizeJson(v, key, seen, trustedMetadata));
    seen.delete(value);
    return out;
  }
  const out: Record<string, unknown> = Object.create(null);
  for (const [k, v] of Object.entries(value as Record<string, unknown>)) {
    if (['__proto__', 'prototype', 'constructor'].includes(k))
      throw new CsoError('INVALID_SCHEMA', 'Unsafe JSON property');
    out[k] = sanitizeJson(v, k, seen, trustedMetadata);
  }
  seen.delete(value as object);
  return out;
}
/** Redact untrusted JSON content. Key names never make an untrusted value exempt. */
export function sanitizeForJson(value: unknown): unknown {
  return sanitizeJson(value, '', new WeakSet<object>(), false);
}
/** Preserve only validated helper identifiers/hashes while redacting all content-bearing fields. */
export function sanitizeHelperForJson(value: unknown): unknown {
  return sanitizeJson(value, '', new WeakSet<object>(), true);
}
export interface ProcessResult {
  code: number;
  stdout: string;
  stderr: string;
  timedOut: boolean;
  truncated: boolean;
  capturedBytes: number;
}
interface GitConfigIdentity {
  path: string;
  exists: boolean;
  dev?: number;
  ino?: number;
  mode?: number;
  size?: number;
  mtimeMs?: number;
  ctimeMs?: number;
  content?: string;
}
const GIT_CONFIG_LIMIT = 1024 * 1024;
interface BoundedMetadataFile {
  dev: number;
  ino: number;
  mode: number;
  nlink: number;
  size: number;
  mtimeMs: number;
  ctimeMs: number;
  content: string;
}
function sameMetadataFile(left: BoundedMetadataFile | Stats, right: BoundedMetadataFile | Stats): boolean {
  return (
    left.dev === right.dev &&
    left.ino === right.ino &&
    left.mode === right.mode &&
    left.nlink === right.nlink &&
    left.size === right.size &&
    left.mtimeMs === right.mtimeMs &&
    left.ctimeMs === right.ctimeMs
  );
}
function boundedMetadataFile(
  path: string,
  maxBytes: number,
  label: string,
  optional = false,
): BoundedMetadataFile | undefined {
  let before: Stats;
  try {
    before = lstatSync(path);
  } catch (error: any) {
    if (optional && error?.code === 'ENOENT') return;
    throw new CsoError(
      error?.code === 'ENOENT' ? 'SNAPSHOT_RACE' : 'UNSAFE_PATH',
      `${label} is not a bounded regular file`,
    );
  }
  if (before.isSymbolicLink() || !before.isFile() || before.nlink !== 1 || before.size > maxBytes)
    throw new CsoError('UNSAFE_PATH', `${label} is not a bounded regular file`);
  let fd: number | undefined;
  try {
    fd = openSync(path, constants.O_RDONLY | (constants.O_NOFOLLOW ?? 0) | (constants.O_NONBLOCK ?? 0));
    const opened = fstatSync(fd);
    if (!opened.isFile() || opened.nlink !== 1 || opened.size > maxBytes || !sameMetadataFile(before, opened))
      throw new CsoError('SNAPSHOT_RACE', `${label} changed while it was opened`);
    const buffer = Buffer.alloc(Math.min(maxBytes + 1, opened.size + 1));
    let bytes = 0,
      count = 0;
    while (bytes < buffer.length && (count = readSync(fd, buffer, bytes, buffer.length - bytes, null)) > 0)
      bytes += count;
    const final = fstatSync(fd),
      after = lstatSync(path);
    if (
      bytes !== opened.size ||
      !final.isFile() ||
      !after.isFile() ||
      after.isSymbolicLink() ||
      !sameMetadataFile(opened, final) ||
      !sameMetadataFile(opened, after)
    )
      throw new CsoError('SNAPSHOT_RACE', `${label} changed while it was read`);
    return {
      dev: opened.dev,
      ino: opened.ino,
      mode: opened.mode,
      nlink: opened.nlink,
      size: opened.size,
      mtimeMs: opened.mtimeMs,
      ctimeMs: opened.ctimeMs,
      content: buffer.subarray(0, bytes).toString('utf8'),
    };
  } catch (error: any) {
    if (error instanceof CsoError) throw error;
    if (['ENOENT', 'ELOOP', 'ENXIO'].includes(error?.code))
      throw new CsoError('SNAPSHOT_RACE', `${label} changed while it was opened`);
    throw new CsoError('UNSAFE_PATH', `${label} could not be read safely`);
  } finally {
    if (fd !== undefined)
      try {
        closeSync(fd);
      } catch {}
  }
}
function boundedConfig(path: string): GitConfigIdentity {
  const file = boundedMetadataFile(path, GIT_CONFIG_LIMIT, 'Repository Git configuration', true);
  if (!file) return { path, exists: false };
  const { content } = file;
  // There is no process-wide "--no-includes" switch for ordinary Git
  // commands. Reject include directives before spawning Git so repository
  // configuration cannot pull policy or executable settings from elsewhere.
  if (/^\s*\[\s*include(?:if)?(?=[\s."\]])/im.test(content))
    throw new CsoError(
      'UNSAFE_PATH',
      'Repository Git config includes are not allowed during a security snapshot',
    );
  return {
    path,
    exists: true,
    dev: file.dev,
    ino: file.ino,
    mode: file.mode,
    size: file.size,
    mtimeMs: file.mtimeMs,
    ctimeMs: file.ctimeMs,
    content,
  };
}
function gitDirectories(repo: string): { gitDir: string; commonDir: string } {
  const marker = join(repo, '.git'),
    stat = lstatSync(marker);
  let gitDir: string;
  if (stat.isDirectory() && !stat.isSymbolicLink()) gitDir = realpathSync(marker);
  else if (stat.isFile() && !stat.isSymbolicLink() && stat.nlink === 1 && stat.size <= 8192) {
    const value = boundedMetadataFile(marker, 8192, 'Repository .git pointer')!.content,
      match = value.match(/^gitdir:\s*(.+?)\s*$/);
    if (!match || value.includes('\0') || value.split(/\r?\n/).filter(Boolean).length !== 1)
      throw new CsoError('UNSAFE_PATH', 'Repository .git pointer is invalid');
    gitDir = realpathSync(resolve(dirname(marker), match[1]));
  } else
    throw new CsoError(
      'UNSAFE_PATH',
      'Repository .git metadata is not a regular directory or worktree pointer',
    );
  const commonMarker = join(gitDir, 'commondir'),
    commonFile = boundedMetadataFile(commonMarker, 8192, 'Repository common Git directory pointer', true);
  let commonDir = gitDir;
  if (commonFile) {
    const value = commonFile.content.trim();
    if (!value || value.includes('\0') || value.includes('\n') || value.includes('\r'))
      throw new CsoError('UNSAFE_PATH', 'Repository common Git directory pointer is invalid');
    commonDir = realpathSync(resolve(gitDir, value));
  }
  return { gitDir, commonDir };
}
function gitConfigIdentities(repo: string): GitConfigIdentity[] {
  const { gitDir, commonDir } = gitDirectories(repo);
  // extensions.worktreeConfig makes config.worktree active in both linked and
  // main worktrees. Bind even its absence so it cannot appear after inspection
  // and feed Git an unchecked include or executable setting.
  return [join(commonDir, 'config'), join(gitDir, 'config.worktree')].map(boundedConfig);
}
function assertGitConfigIdentities(expected: GitConfigIdentity[]): void {
  for (const item of expected) {
    const current = boundedConfig(item.path);
    if (
      current.exists !== item.exists ||
      current.dev !== item.dev ||
      current.ino !== item.ino ||
      current.mode !== item.mode ||
      current.size !== item.size ||
      current.mtimeMs !== item.mtimeMs ||
      current.ctimeMs !== item.ctimeMs ||
      current.content !== item.content
    )
      throw new CsoError('SNAPSHOT_RACE', 'Repository Git configuration changed during a metadata operation');
  }
}
function hardenGit(file: string, args: string[]): { args: string[]; configs?: GitConfigIdentity[] } {
  if (!/^(?:git|git\.exe)$/i.test(basename(file))) return { args };
  let trusted: string;
  try {
    trusted = executable('git');
  } catch {
    return { args };
  }
  if (realpathSync(file) !== trusted) return { args };
  const positions = args.flatMap((value, index) => (value === '-C' ? [index] : []));
  if (positions.length !== 1 || positions[0] + 1 >= args.length)
    throw new CsoError(
      'INVALID_ARGUMENT',
      'CSO Git operations require exactly one audited working directory',
    );
  const position = positions[0],
    requested = args[position + 1];
  if (!isAbsolute(requested))
    throw new CsoError(
      'INVALID_ARGUMENT',
      'CSO Git operations require an absolute audited working directory',
    );
  const repo = realpathSync(requested),
    stat = statSync(repo);
  if (!stat.isDirectory())
    throw new CsoError('MISSING_INPUT', 'Audited Git working directory is not a directory');
  const configs = gitConfigIdentities(repo),
    nullPath = process.platform === 'win32' ? 'NUL' : '/dev/null',
    // Git for Windows accepts NUL for ordinary file-valued settings, but its
    // config include machinery treats NUL as a failing include. Its MSYS path
    // layer maps /dev/null correctly for this one directive.
    includeNullPath = process.platform === 'win32' ? '/dev/null' : nullPath;
  const prefix = args.slice(0, position),
    command = args.slice(position + 2);
  return {
    configs,
    args: [
      ...prefix,
      '--no-replace-objects',
      '-c',
      'core.fsmonitor=false',
      '-c',
      `core.hooksPath=${nullPath}`,
      '-c',
      `core.attributesFile=${nullPath}`,
      '-c',
      `core.excludesFile=${nullPath}`,
      '-c',
      'core.ignoreCase=false',
      '-c',
      'core.precomposeUnicode=false',
      '-c',
      'core.untrackedCache=false',
      '-c',
      `include.path=${includeNullPath}`,
      '-c',
      'core.pager=cat',
      '-C',
      repo,
      `--work-tree=${repo}`,
      ...command,
    ],
  };
}
export async function runProcess(
  file: string,
  args: string[],
  opts: {
    cwd: string;
    env: Record<string, string>;
    timeoutMs?: number;
    maxBytes?: number;
    input?: string;
    raw?: boolean; // Only for inert Git framing or private helper/Docker control JSON that is validated before use. Never print or persist raw results.
  },
): Promise<ProcessResult> {
  if (!isAbsolute(file) || !isAbsolute(opts.cwd) || !existsSync(opts.cwd))
    throw new CsoError(
      'INVALID_ARGUMENT',
      'Children require absolute executables and an existing trusted working directory',
    );
  if (!args.every((a) => typeof a === 'string' && !a.includes('\0')))
    throw new CsoError('INVALID_ARGUMENT', 'Invalid child argument');
  const hardened = hardenGit(file, args);
  args = hardened.args;
  const cap = Math.min(opts.maxBytes ?? MAX_OUTPUT, MAX_OUTPUT);
  return new Promise((resolve, reject) => {
    const child = spawn(file, args, {
      cwd: opts.cwd,
      env: opts.env,
      stdio: ['pipe', 'pipe', 'pipe'],
      detached: process.platform !== 'win32',
    });
    const out: Buffer[] = [],
      err: Buffer[] = [],
      ordered: Buffer[] = [];
    let bytes = 0,
      timedOut = false,
      truncated = false;
    const kill = () => {
      try {
        if (process.platform !== 'win32' && child.pid) process.kill(-child.pid, 'SIGKILL');
        else child.kill('SIGKILL');
      } catch {}
    };
    const timer = setTimeout(
      () => {
        timedOut = true;
        kill();
      },
      Math.max(1, Math.min(opts.timeoutMs ?? 30_000, 300_000)),
    );
    const capture = (target: Buffer[]) => (chunk: Buffer) => {
      bytes += chunk.length;
      if (bytes > cap) {
        truncated = true;
        kill();
        return;
      }
      target.push(chunk);
      ordered.push(chunk);
    };
    child.stdout.on('data', capture(out));
    child.stderr.on('data', capture(err));
    child.on('error', () => {
      clearTimeout(timer);
      reject(new CsoError('TOOL_UNAVAILABLE', 'Trusted child process could not start'));
    });
    child.on('close', (code) => {
      clearTimeout(timer);
      try {
        if (hardened.configs) assertGitConfigIdentities(hardened.configs);
        // Never expose a truncated tail: it might be the beginning of a secret.
        const stdout = truncated ? '[output withheld: size limit]' : Buffer.concat(out).toString('utf8');
        const stderr = truncated ? '' : Buffer.concat(err).toString('utf8');
        if (opts.raw) {
          resolve({ code: code ?? -1, stdout, stderr, timedOut, truncated, capturedBytes: bytes });
          return;
        }
        // A token may be split across stdout/stderr. Stream ordering is not
        // recoverable here, so scan both concatenation orders and withhold both
        // channels when either reveals a cross-stream sensitive span.
        const forward = stdout + stderr,
          reverse = stderr + stdout,
          chronological = Buffer.concat(ordered).toString('utf8');
        if ([stdout, stderr, forward, reverse, chronological].some((value) => redact(value) !== value)) {
          resolve({
            code: code ?? -1,
            stdout: '[sensitive process output redacted]',
            stderr: '',
            timedOut,
            truncated,
            capturedBytes: bytes,
          });
          return;
        }
        resolve({ code: code ?? -1, stdout, stderr, timedOut, truncated, capturedBytes: bytes });
      } catch (e) {
        reject(e);
      }
    });
    child.stdin.on('error', () => {});
    child.stdin.end(opts.input);
  });
}
export async function git(repo: string, args: string[], home: string): Promise<string> {
  const result = await runProcess(executable('git'), ['--no-optional-locks', '-C', repo, ...args], {
    cwd: home,
    env: childEnvironment(home),
    raw: true,
    timeoutMs: 15_000,
  });
  if (result.code || result.timedOut || result.truncated) {
    // Git stderr and argv can contain repository paths, refs, and configured
    // content. Name only the fixed helper-owned operation and bounded process
    // outcome so native failures are actionable without exposing either.
    const knownOperations = new Set([
        'rev-parse',
        'symbolic-ref',
        'ls-files',
        'ls-tree',
        'log',
        'merge-base',
      ]),
      operation = args.find((value) => knownOperations.has(value)) ?? 'metadata',
      phase =
        operation === 'rev-parse' && args.includes('--show-object-format')
          ? 'object-format'
          : operation === 'rev-parse' && args.includes('--is-inside-work-tree')
            ? 'worktree-probe'
            : operation,
      reason = /not a git repository|outside repository/i.test(result.stderr)
        ? 'repository unavailable'
        : /dubious ownership/i.test(result.stderr)
          ? 'repository ownership rejected'
          : /(?:bad|invalid|unable to read).*config|config (?:error|file)/i.test(result.stderr)
            ? 'configuration rejected'
            : /unknown option|unknown switch|unrecognized option|usage:/i.test(result.stderr)
              ? 'unsupported invocation'
              : /(?:cannot|could not|unable to) (?:chdir|change directory)|no such file or directory/i.test(
                    result.stderr,
                  )
                ? 'path unavailable'
                : 'request rejected',
      outcome = result.timedOut
        ? 'timed out'
        : result.truncated
          ? 'exceeded the output limit'
          : `exited ${result.code}`;
    throw new CsoError(
      'MISSING_INPUT',
      `Could not read bounded Git metadata: ${phase} ${outcome} (${reason}); source may not be a Git repository`,
    );
  }
  return result.stdout;
}