from __future__ import annotations

import json
import os
import re
import shutil
import stat
import tempfile
import time
import uuid
import zipfile
from dataclasses import asdict, dataclass
from pathlib import Path, PurePosixPath
from typing import Any

DOMAINS = (
    'Astronomy',
    'Chemistry',
    'Earth',
    'Energy',
    'Information',
    'Life',
    'Material',
    'Math',
    'Neuroscience',
    'Physics',
)
DOMAIN_TOKEN_RE = re.compile(r'^[A-Za-z][A-Za-z0-9-]*$')
TASK_ID_RE = re.compile(r'^([A-Za-z][A-Za-z0-9-]*)_(\d{3})$')
STALE_TOKENS = (
    '/mnt/shared-storage-user/',
    'SGI-EvalAgent',
    'prior_literature',
    'target_literature',
)
STALE_TASK_REF_RE = re.compile(r'(?:\./|/)tasks/[\w/.\-]+')
DATA_REF_RE = re.compile(r"""\./data/[^'"`\n;,]+""")
EXPECTED_TOP_LEVEL = {'data', 'related_work', 'target_study', 'task_info.json'}
EXPECTED_TARGET_STUDY = ('checklist.json', 'images/', 'paper.pdf')
EXPECTED_TASK_INFO_KEYS = ('data', 'task')
EXPECTED_DATA_ITEM_KEYS = ('description', 'name', 'path', 'type')
EXPECTED_CHECKLIST_ITEM_KEYS = ('content', 'keywords', 'path', 'type', 'weight')
IGNORED_ARCHIVE_PARTS = {'__MACOSX'}
IGNORED_ARCHIVE_NAMES = {'.DS_Store'}
DEFAULT_MAX_FILES = int(os.environ.get('RCB_SPACE_MAX_FILES', '5000'))
DEFAULT_MAX_TOTAL_BYTES = int(os.environ.get('RCB_SPACE_MAX_TOTAL_BYTES', str(5 * 1024 * 1024 * 1024)))
DEFAULT_MAX_SINGLE_FILE_BYTES = int(os.environ.get('RCB_SPACE_MAX_SINGLE_FILE_BYTES', str(1024 * 1024 * 1024)))
WORK_DIR_PREFIX = 'rcb_space_submit_'
ARCHIVE_PREFIX = 'rcb_space_upload_'
TEMP_ROOTS = tuple(
    Path(root).resolve()
    for root in {
        tempfile.gettempdir(),
        os.environ.get('GRADIO_TEMP_DIR', ''),
    }
    if root
)


@dataclass
class SubmissionMetadata:
    domain: str
    submitter: str
    email: str
    paper_title: str
    paper_url: str
    notes: str = ''


@dataclass
class ArchiveStats:
    file_count: int
    total_bytes: int


@dataclass
class PreparedSubmission:
    work_dir: str
    uploaded_task_dir: str
    staged_task_dir: str
    assigned_task_id: str
    archive_stats: ArchiveStats
    metadata: SubmissionMetadata

    def to_state(self) -> dict[str, Any]:
        return {
            'work_dir': self.work_dir,
            'uploaded_task_dir': self.uploaded_task_dir,
            'staged_task_dir': self.staged_task_dir,
            'assigned_task_id': self.assigned_task_id,
            'archive_stats': asdict(self.archive_stats),
            'metadata': asdict(self.metadata),
        }

    @classmethod
    def from_state(cls, state: dict[str, Any]) -> 'PreparedSubmission':
        return cls(
            work_dir=state['work_dir'],
            uploaded_task_dir=state['uploaded_task_dir'],
            staged_task_dir=state['staged_task_dir'],
            assigned_task_id=state['assigned_task_id'],
            archive_stats=ArchiveStats(**state['archive_stats']),
            metadata=SubmissionMetadata(**state['metadata']),
        )


class ValidationError(RuntimeError):
    pass


def normalize_domain_token(domain: str) -> str:
    value = re.sub(r'[\s_]+', '-', (domain or '').strip())
    value = re.sub(r'-{2,}', '-', value)
    return value.strip('-')


def load_json(path: Path) -> Any:
    try:
        return json.loads(path.read_text(encoding='utf-8'))
    except Exception as exc:
        raise ValidationError(f'Failed to parse JSON: {path}: {exc}') from exc


def rel(path: Path, base: Path) -> str:
    try:
        return str(path.relative_to(base))
    except Exception:
        return str(path)


def _target_entries(target_dir: Path) -> tuple[str, ...]:
    return tuple(sorted(x.name + ('/' if x.is_dir() else '') for x in target_dir.iterdir()))


def _is_ignored_archive_path(path: PurePosixPath) -> bool:
    return any(part in IGNORED_ARCHIVE_PARTS for part in path.parts) or path.name in IGNORED_ARCHIVE_NAMES or path.name.startswith('._')


def _is_zip_symlink(info: zipfile.ZipInfo) -> bool:
    mode = info.external_attr >> 16
    return stat.S_ISLNK(mode)


def _iter_data_refs(text: str) -> list[str]:
    refs = []
    for raw_ref in DATA_REF_RE.findall(text):
        ref = raw_ref.rstrip('.')
        if ref not in refs:
            refs.append(ref)
    return refs


def _iter_visible_files(root: Path) -> set[Path]:
    return {
        path for path in root.rglob('*')
        if path.is_file() and not any(part.startswith('.') for part in path.relative_to(root).parts)
    }


def cleanup_work_dir(work_dir: str | Path | None) -> None:
    if not work_dir:
        return
    shutil.rmtree(Path(work_dir), ignore_errors=True)


def cleanup_submission_state(state: dict[str, Any] | None) -> None:
    if not state or not isinstance(state, dict):
        return
    cleanup_work_dir(state.get('work_dir'))


def _is_under_temp_root(path: Path) -> bool:
    try:
        resolved = path.resolve()
    except OSError:
        return False
    return any(root == resolved or root in resolved.parents for root in TEMP_ROOTS)


def cleanup_uploaded_archive(archive_path: str | Path | None) -> None:
    if not archive_path:
        return
    path = Path(archive_path)
    if not path.exists() or not path.is_file():
        return
    if path.suffix.lower() != '.zip':
        return
    if not _is_under_temp_root(path):
        return
    if not path.name.startswith(ARCHIVE_PREFIX):
        return
    try:
        path.unlink()
    except OSError:
        pass


def persist_uploaded_archive(archive_path: str | Path) -> Path:
    source = Path(archive_path)
    if not source.exists() or not source.is_file():
        raise ValidationError(f'Uploaded archive does not exist: {source}')
    if source.suffix.lower() != '.zip':
        raise ValidationError('Only .zip uploads are supported.')

    managed_root = Path(tempfile.gettempdir())
    managed_path = managed_root / f'{ARCHIVE_PREFIX}{uuid.uuid4().hex}.zip'
    shutil.copy2(source, managed_path)
    return managed_path


def cleanup_stale_managed_files(max_age_seconds: int) -> int:
    if max_age_seconds <= 0:
        return 0

    temp_root = Path(tempfile.gettempdir())
    if not temp_root.exists():
        return 0

    cutoff = time.time() - max_age_seconds
    removed = 0
    for path in temp_root.iterdir():
        if path.is_dir():
            if not path.name.startswith(WORK_DIR_PREFIX):
                continue
        elif path.is_file():
            if not path.name.startswith(ARCHIVE_PREFIX) or path.suffix.lower() != '.zip':
                continue
        else:
            continue
        try:
            if path.stat().st_mtime > cutoff:
                continue
        except OSError:
            continue
        if path.is_dir():
            shutil.rmtree(path, ignore_errors=True)
        else:
            try:
                path.unlink()
            except OSError:
                continue
        removed += 1
    return removed


def create_work_dir() -> Path:
    return Path(tempfile.mkdtemp(prefix=WORK_DIR_PREFIX))


def extract_submission_zip(
    archive_path: str | Path,
    work_dir: str | Path,
    *,
    max_files: int = DEFAULT_MAX_FILES,
    max_total_bytes: int = DEFAULT_MAX_TOTAL_BYTES,
    max_single_file_bytes: int = DEFAULT_MAX_SINGLE_FILE_BYTES,
) -> tuple[Path, ArchiveStats]:
    archive_path = Path(archive_path)
    work_dir = Path(work_dir)
    extract_root = work_dir / 'extracted'
    extract_root.mkdir(parents=True, exist_ok=True)

    if archive_path.suffix.lower() != '.zip':
        raise ValidationError('Only .zip uploads are supported.')

    file_count = 0
    total_bytes = 0
    safe_infos: list[tuple[zipfile.ZipInfo, PurePosixPath]] = []

    with zipfile.ZipFile(archive_path) as zf:
        infos = zf.infolist()
        if not infos:
            raise ValidationError('The uploaded zip archive is empty.')

        for info in infos:
            raw_name = info.filename.replace('\\', '/')
            if not raw_name:
                continue
            posix_path = PurePosixPath(raw_name)
            if _is_ignored_archive_path(posix_path):
                continue
            if posix_path.is_absolute() or '..' in posix_path.parts:
                raise ValidationError(f'Archive contains an invalid path: {raw_name}')
            if _is_zip_symlink(info):
                raise ValidationError(f'Archive contains a symbolic link, which is not allowed: {raw_name}')
            safe_infos.append((info, posix_path))
            if info.is_dir():
                continue
            file_count += 1
            total_bytes += info.file_size
            if info.file_size > max_single_file_bytes:
                raise ValidationError(
                    f'Archive file exceeds the per-file limit ({max_single_file_bytes} bytes): {raw_name}'
                )
            if file_count > max_files:
                raise ValidationError(f'Archive exceeds the file-count limit ({max_files}).')
            if total_bytes > max_total_bytes:
                raise ValidationError(f'Archive exceeds the total-size limit ({max_total_bytes} bytes).')

        if file_count == 0:
            raise ValidationError('The uploaded zip archive does not contain any files.')

        for info, posix_path in safe_infos:
            destination = extract_root.joinpath(*posix_path.parts)
            if info.is_dir():
                destination.mkdir(parents=True, exist_ok=True)
                continue
            destination.parent.mkdir(parents=True, exist_ok=True)
            with zf.open(info) as src, destination.open('wb') as dst:
                shutil.copyfileobj(src, dst)

    return extract_root, ArchiveStats(file_count=file_count, total_bytes=total_bytes)


def find_single_task_dir(extract_root: str | Path) -> Path:
    extract_root = Path(extract_root)
    entries = []
    for path in sorted(extract_root.iterdir(), key=lambda p: p.name.lower()):
        if path.name in IGNORED_ARCHIVE_NAMES or path.name in IGNORED_ARCHIVE_PARTS or path.name.startswith('._'):
            continue
        entries.append(path)

    if len(entries) != 1 or not entries[0].is_dir():
        names = [p.name for p in entries]
        raise ValidationError(
            'Zip must contain exactly one top-level task directory. '
            f'Found: {names if names else "(none)"}'
        )
    return entries[0]


def validate_submission_metadata(metadata: SubmissionMetadata) -> list[str]:
    errors: list[str] = []
    normalized_domain = normalize_domain_token(metadata.domain)
    if not normalized_domain:
        errors.append('A domain is required.')
    elif not DOMAIN_TOKEN_RE.fullmatch(normalized_domain):
        errors.append(
            'Domain must start with a letter and contain only letters, numbers, or hyphens '
            f'after normalization. Got: {metadata.domain!r}'
        )
    if not metadata.submitter.strip():
        errors.append('Submitter name or HF username is required.')
    if not metadata.email.strip():
        errors.append('Contact email is required.')
    elif not re.fullmatch(r'[^@\s]+@[^@\s]+\.[^@\s]+', metadata.email.strip()):
        errors.append('Contact email must be a valid email address.')
    if not metadata.paper_title.strip():
        errors.append('Paper title is required.')
    if not metadata.paper_url.strip():
        errors.append('Paper URL or DOI is required.')
    return errors


def validate_task_dir(
    task_dir: str | Path,
    *,
    enforce_task_name: bool = True,
    expected_domain: str | None = None,
) -> list[str]:
    task_dir = Path(task_dir)
    errors: list[str] = []
    task_name = task_dir.name
    match = TASK_ID_RE.match(task_name)

    if enforce_task_name:
        if not match:
            errors.append(f'invalid task directory name: {task_name}')
        elif expected_domain and match.group(1) != expected_domain:
            errors.append(f'task directory domain {match.group(1)!r} does not match selected domain {expected_domain!r}')
    elif expected_domain and match and match.group(1) != expected_domain:
        errors.append(f'task directory domain {match.group(1)!r} does not match selected domain {expected_domain!r}')

    if not task_dir.is_dir():
        return [f'task directory does not exist: {task_dir}']

    actual_top = {p.name for p in task_dir.iterdir()}
    if actual_top != EXPECTED_TOP_LEVEL:
        errors.append(f'top-level entries mismatch: expected {sorted(EXPECTED_TOP_LEVEL)}, got {sorted(actual_top)}')

    data_dir = task_dir / 'data'
    related_dir = task_dir / 'related_work'
    target_dir = task_dir / 'target_study'
    task_info_path = task_dir / 'task_info.json'
    checklist_path = target_dir / 'checklist.json'
    paper_path = target_dir / 'paper.pdf'
    images_dir = target_dir / 'images'

    if not data_dir.is_dir():
        errors.append('missing data/ directory')
    if not related_dir.is_dir():
        errors.append('missing related_work/ directory')
    if not target_dir.is_dir():
        errors.append('missing target_study/ directory')
    if not task_info_path.is_file():
        errors.append('missing task_info.json')
        return errors
    if not checklist_path.is_file():
        errors.append('missing target_study/checklist.json')
        return errors
    if not paper_path.is_file():
        errors.append('missing target_study/paper.pdf')
    if not images_dir.is_dir():
        errors.append('missing target_study/images/ directory')

    try:
        task_info = load_json(task_info_path)
    except ValidationError as exc:
        errors.append(str(exc))
        return errors

    if not isinstance(task_info, dict):
        errors.append('task_info.json root must be a JSON object')
        return errors

    if tuple(sorted(task_info.keys())) != EXPECTED_TASK_INFO_KEYS:
        errors.append(f'task_info.json keys mismatch: {sorted(task_info.keys())}')

    if not isinstance(task_info.get('task'), str) or not task_info['task'].strip():
        errors.append('task_info.json field `task` must be a non-empty string')
    if not isinstance(task_info.get('data'), list):
        errors.append('task_info.json field `data` must be a list')
        task_info['data'] = []

    declared_paths: set[str] = set()
    for idx, item in enumerate(task_info['data']):
        prefix = f'task_info.data[{idx}]'
        if not isinstance(item, dict):
            errors.append(f'{prefix} must be an object')
            continue
        if tuple(sorted(item.keys())) != EXPECTED_DATA_ITEM_KEYS:
            errors.append(f'{prefix} keys mismatch: {sorted(item.keys())}')
            continue
        for field in EXPECTED_DATA_ITEM_KEYS:
            if not isinstance(item.get(field), str) or not item[field].strip():
                errors.append(f'{prefix}.{field} must be a non-empty string')
        data_path = item.get('path')
        if not isinstance(data_path, str):
            continue
        if not data_path.startswith('./data/') and data_path != './data':
            errors.append(f'{prefix}.path must start with ./data/: {data_path}')
            continue
        if '\\' in data_path or '..' in Path(data_path).parts:
            errors.append(f'{prefix}.path contains an invalid segment: {data_path}')
            continue
        if data_path in declared_paths:
            errors.append(f'duplicate data path declaration: {data_path}')
            continue
        declared_paths.add(data_path)
        rel_path = data_path[2:] if data_path.startswith('./') else data_path
        target = task_dir / rel_path
        if not target.exists():
            errors.append(f'{prefix}.path does not exist: {data_path}')
            continue
        if target.is_dir():
            nested_files = {p for p in target.rglob('*') if p.is_file()}
            if not nested_files:
                errors.append(f'{prefix}.path points to an empty directory: {data_path}')
        elif not target.is_file():
            errors.append(f'{prefix}.path is neither file nor directory: {data_path}')
        description = item.get('description', '')
        if any(token in description for token in STALE_TOKENS):
            errors.append(f'{prefix}.description still contains stale source paths or legacy directories')

    related_entries = sorted(related_dir.iterdir(), key=lambda p: p.name) if related_dir.exists() else []
    related_files = [p for p in related_entries if p.is_file()]
    related_dirs = [p for p in related_entries if p.is_dir()]
    if related_dirs:
        errors.append('related_work/ must not contain subdirectories')
    if not related_files:
        errors.append('related_work/ must contain at least one PDF')
    pdf_names = []
    for path in related_files:
        if not re.fullmatch(r'paper_\d{3}\.pdf', path.name):
            errors.append(f'invalid related_work filename: {path.name}')
        pdf_names.append(path.name)
    expected_pdf_names = [f'paper_{i:03d}.pdf' for i in range(len(pdf_names))]
    if pdf_names and pdf_names != expected_pdf_names:
        errors.append(f'related_work PDFs must be contiguous starting from paper_000.pdf; got {pdf_names}')

    if target_dir.exists() and _target_entries(target_dir) != EXPECTED_TARGET_STUDY:
        errors.append(f'target_study entries mismatch: {_target_entries(target_dir)}')

    try:
        checklist = load_json(checklist_path)
    except ValidationError as exc:
        errors.append(str(exc))
        return errors

    if not isinstance(checklist, list):
        errors.append('checklist.json root must be a list')
        return errors

    if not checklist:
        errors.append('checklist.json must be a non-empty list')
        checklist = []

    referenced_images: set[str] = set()
    for idx, item in enumerate(checklist):
        prefix = f'checklist[{idx}]'
        if not isinstance(item, dict):
            errors.append(f'{prefix} must be an object')
            continue
        if tuple(sorted(item.keys())) != EXPECTED_CHECKLIST_ITEM_KEYS:
            errors.append(f'{prefix} keys mismatch: {sorted(item.keys())}')
            continue
        item_type = item.get('type')
        if item_type not in {'text', 'image'}:
            errors.append(f'{prefix}.type must be text or image, got {item_type!r}')
        if not isinstance(item.get('content'), str) or not item['content'].strip():
            errors.append(f'{prefix}.content must be a non-empty string')
        if not isinstance(item.get('keywords'), list) or not item['keywords']:
            errors.append(f'{prefix}.keywords must be a non-empty list')
        elif not all(isinstance(x, str) and x.strip() for x in item['keywords']):
            errors.append(f'{prefix}.keywords must contain only non-empty strings')
        if not isinstance(item.get('weight'), (int, float)) or item['weight'] <= 0:
            errors.append(f'{prefix}.weight must be a positive number')
        path_value = item.get('path')
        if item_type == 'text':
            if path_value is not None:
                errors.append(f'{prefix}.path must be null for text items')
        elif item_type == 'image':
            if not isinstance(path_value, str) or not path_value.startswith('images/'):
                errors.append(f'{prefix}.path must start with images/ for image items')
            else:
                if '\\' in path_value or '..' in Path(path_value).parts:
                    errors.append(f'{prefix}.path contains an invalid segment: {path_value}')
                image_path = target_dir / path_value
                if not image_path.is_file():
                    errors.append(f'{prefix}.path does not exist: {path_value}')
                referenced_images.add(path_value)

    actual_image_files = {str(p.relative_to(target_dir)) for p in _iter_visible_files(images_dir)} if images_dir.exists() else set()
    missing_images = sorted(referenced_images - actual_image_files)
    if missing_images:
        errors.append('checklist image references are missing from target_study/images: ' + ', '.join(missing_images[:20]))

    for text_path in (task_info_path, checklist_path):
        text = text_path.read_text(encoding='utf-8')
        if any(token in text for token in STALE_TOKENS):
            errors.append(f'stale source path tokens remain in {rel(text_path, task_dir)}')

    task_text = task_info.get('task', '') if isinstance(task_info, dict) else ''
    if isinstance(task_text, str):
        for ref in STALE_TASK_REF_RE.findall(task_text):
            errors.append(f'task description contains stale path: {ref}')

    for idx, item in enumerate(task_info.get('data', [])):
        desc = item.get('description', '')
        for ref in STALE_TASK_REF_RE.findall(desc):
            errors.append(f'task_info.data[{idx}].description contains stale path: {ref}')
        for data_ref in _iter_data_refs(desc):
            rel_ref = data_ref[2:]
            if not (task_dir / rel_ref).exists():
                errors.append(f'task_info.data[{idx}].description references non-existent path: {data_ref}')

    return errors


def stage_submission(task_dir: str | Path, assigned_task_id: str, work_dir: str | Path) -> Path:
    task_dir = Path(task_dir)
    work_dir = Path(work_dir)
    staged_root = work_dir / 'staged'
    staged_root.mkdir(parents=True, exist_ok=True)
    staged_task_dir = staged_root / assigned_task_id
    if staged_task_dir.exists():
        shutil.rmtree(staged_task_dir)
    shutil.copytree(task_dir, staged_task_dir)
    return staged_task_dir


def build_public_report(prepared: PreparedSubmission) -> dict[str, Any]:
    return {
        'status': 'ok',
        'assigned_task_id': prepared.assigned_task_id,
        'archive': {
            'file_count': prepared.archive_stats.file_count,
            'total_bytes': prepared.archive_stats.total_bytes,
        },
        'metadata': {
            'domain': prepared.metadata.domain,
            'submitter': prepared.metadata.submitter,
            'paper_title': prepared.metadata.paper_title,
            'paper_url': prepared.metadata.paper_url,
        },
    }


def validate_and_prepare_submission(
    archive_path: str | Path,
    metadata: SubmissionMetadata,
    assigned_task_id: str,
) -> PreparedSubmission:
    metadata_errors = validate_submission_metadata(metadata)
    if metadata_errors:
        raise ValidationError('\n'.join(metadata_errors))

    work_dir = create_work_dir()
    try:
        extract_root, archive_stats = extract_submission_zip(archive_path, work_dir)
        uploaded_task_dir = find_single_task_dir(extract_root)
        errors = validate_task_dir(uploaded_task_dir, enforce_task_name=False, expected_domain=metadata.domain)
        if errors:
            raise ValidationError('\n'.join(errors))
        staged_task_dir = stage_submission(uploaded_task_dir, assigned_task_id, work_dir)
        return PreparedSubmission(
            work_dir=str(work_dir),
            uploaded_task_dir=str(uploaded_task_dir),
            staged_task_dir=str(staged_task_dir),
            assigned_task_id=assigned_task_id,
            archive_stats=archive_stats,
            metadata=metadata,
        )
    except Exception:
        cleanup_work_dir(work_dir)
        raise