"""Export current workshop instructions and code as inert bytes, never credentials."""
import sys
sys.dont_write_bytecode = True
import argparse
import datetime
import hashlib
import json
import os
from pathlib import Path, PurePosixPath
import re
import zipfile

SHA = lambda raw: hashlib.sha256(raw).hexdigest()
ROOT_FILES = {'SKILL.md', 'FILES.sha256', 'runtime-lock.json'}


def permitted(name):
    parts = PurePosixPath(name).parts
    if not parts or '..' in parts or name.startswith('/') or '\\' in name or ':' in name:
        return False
    if name in ROOT_FILES:
        return True
    # Instance binding, envelopes, key material, environment and employee state
    # are outside these explicit documentation/code namespaces.
    if any(re.search(r'credential|binding|envelope|private|secret|recipient|decrypt|\.env', p, re.I) for p in parts):
        return False
    if parts[0] == 'references':
        return name.endswith('.md') or name == 'references/business-data-dictionary.json'
    return parts[0] == 'scripts' and Path(name).suffix in ('.py', '.mjs', '.js')


def export(skill_root, out):
    root = Path(skill_root).absolute()
    target = Path(out).absolute()
    for path in (root, target):
        if any(p.is_symlink() for p in (path, *path.parents)):
            raise ValueError('REDIRECTED_PATH')
    if not root.is_dir() or not (root / 'SKILL.md').is_file():
        raise ValueError('WORKSHOP_SKILL_NOT_FOUND')
    if target.exists() or root == target or root in target.parents:
        raise ValueError('NEW_OUTPUT_OUTSIDE_SKILL_REQUIRED')
    files = {}
    for path in root.rglob('*'):
        name = path.relative_to(root).as_posix()
        if not permitted(name):
            continue
        if any(p.is_symlink() for p in (path, *path.parents)):
            raise ValueError('REDIRECTED_SKILL_FILE')
        if not path.is_file():
            continue
        if path.stat().st_size > 8 * 1024 * 1024:
            raise ValueError('SKILL_FILE_TOO_LARGE')
        files[name] = path.read_bytes()
    if len(files) > 100 or sum(map(len, files.values())) > 20 * 1024 * 1024:
        raise ValueError('SKILL_EXPORT_TOO_LARGE')
    manifest_state = []
    manifest = files.get('FILES.sha256')
    if manifest:
        for line in manifest.decode('utf-8-sig').splitlines():
            digest, sep, name = line.partition('  ')
            if not sep or not re.fullmatch('[a-f0-9]{64}', digest):
                raise ValueError('INVALID_INSTALLED_MANIFEST')
            manifest_state.append({'path': name,
                'state': ('MATCH' if SHA(files[name]) == digest else 'MISMATCH')
                         if name in files else 'NOT_EXPORTED'})
    # Re-read the public files before sealing; do not copy during an upgrade.
    if any((root / name).read_bytes() != raw for name, raw in files.items()):
        raise ValueError('SKILL_CHANGED_DURING_EXPORT')
    receipt = {'schema': 'ksf.workshop.skill-readonly-export.v1',
        'exportedAt': datetime.datetime.now(datetime.timezone.utc).isoformat(),
        'skillName': 'ksf-workshop-runtime', 'skillSha256': SHA(files['SKILL.md']),
        'skillLines': len(files['SKILL.md'].decode('utf-8-sig').splitlines()),
        'files': [{'path': n, 'bytes': len(b), 'sha256': SHA(b)} for n, b in sorted(files.items())],
        'installedManifest': manifest_state,
        'readOnly': True, 'installedFilesModified': False, 'exportFilesWritten': True,
        'packageCodeExecuted': False, 'credentialsExported': False,
        'databaseWrites': 0, 'networkCalls': 0, 'paidCalls': 0,
        'agentReloadVerified': False, 'actualBusinessWriteVerified': False}
    target.mkdir(parents=True, mode=0o700)
    archive = target / 'ksf-workshop-runtime-current.zip'
    payload = {'ksf-workshop-runtime/' + n: b for n, b in files.items()}
    payload['EXPORT.json'] = (json.dumps(receipt, ensure_ascii=False, indent=2) + '\n').encode('utf-8')
    payload['EXPORT.sha256'] = ''.join(SHA(b) + '  ' + n + '\n' for n, b in sorted(payload.items())).encode('utf-8')
    with zipfile.ZipFile(archive, 'x', zipfile.ZIP_DEFLATED) as z:
        for name, raw in payload.items():
            z.writestr(name, raw)
    os.chmod(archive, 0o600)
    with zipfile.ZipFile(archive) as z:
        if z.testzip() is not None or any(z.read(n) != b for n, b in payload.items()):
            raise ValueError('EXPORT_VERIFICATION_FAILED')
    result = {'ok': True, 'archive': str(archive), 'bytes': archive.stat().st_size,
        'sha256': SHA(archive.read_bytes()), 'skillSha256': receipt['skillSha256'],
        'skillLines': receipt['skillLines'], 'files': len(files),
        'installedManifestMismatches': [r['path'] for r in manifest_state if r['state'] == 'MISMATCH'],
        'installedFilesModified': False, 'databaseWrites': 0, 'paidCalls': 0}
    (target / 'export-receipt.json').write_text(json.dumps(result, ensure_ascii=False, indent=2) + '\n', encoding='utf-8')
    os.chmod(target / 'export-receipt.json', 0o600)
    return result


if __name__ == '__main__':
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument('--skill-root', default='/opt/data/skills/ksf-workshop-runtime')
    parser.add_argument('--out', required=True)
    args = parser.parse_args()
    try:
        print(json.dumps(export(args.skill_root, args.out), ensure_ascii=False))
    except (ValueError, OSError, KeyError) as error:
        code = str(error) if re.fullmatch('[A-Z][A-Z0-9_]+', str(error)) else 'EXPORT_FAILED'
        print(json.dumps({'ok': False, 'error': {'code': code}, 'installedFilesModified': False}, ensure_ascii=False))
        sys.exit(1)