"""
Hermes Web UI -- File upload: multipart parser and upload handler.
"""
import mimetypes
import os
import re as _re
import email.parser
import tempfile
from pathlib import Path

from api.config import MAX_UPLOAD_BYTES, STATE_DIR
from api.helpers import j, bad
from api.models import get_session
from api.workspace import safe_resolve_ws, resolve_trusted_workspace


def _max_extracted_bytes() -> int:
    """Total-extracted-bytes cap for archive uploads (zip/tar-bomb guard).

    Independently tunable from the upload size cap via
    HERMES_WEBUI_MAX_EXTRACTED_MB; defaults to 10x the upload cap. Read at call
    time (not import) so the value reflects the running process's environment
    and is exercisable by tests against the out-of-process test server.
    """
    raw = os.getenv("HERMES_WEBUI_MAX_EXTRACTED_MB", "").strip()
    if raw:
        try:
            mb = float(raw)
            if mb > 0:
                return int(mb * 1024 * 1024)
        except ValueError:
            pass
    return 10 * MAX_UPLOAD_BYTES


# Back-compat module constant (some call sites / tests reference it). The
# authoritative value is _max_extracted_bytes(), read at extraction time.
_MAX_EXTRACTED_BYTES = 10 * MAX_UPLOAD_BYTES


def parse_multipart(rfile, content_type, content_length) -> tuple:
    import re as _re, email.parser as _ep
    # Imported locally (not just module-level) so the function stays
    # self-contained — some tests exec() this function's source in an isolated
    # namespace, and a bare module global would NameError there.
    try:
        from api.config import MAX_UPLOAD_BYTES as _MAX_UPLOAD_BYTES
    except Exception:
        _MAX_UPLOAD_BYTES = 20 * 1024 * 1024
    m = _re.search(r'boundary=([^;\s]+)', content_type)
    if not m:
        raise ValueError('No boundary in Content-Type')
    boundary = m.group(1).strip('"').encode()
    # Centralized length guard for ALL upload callers: a missing/garbage or
    # NEGATIVE Content-Length must never reach rfile.read(<0), which reads the
    # stream unbounded (read(-1) == read-to-EOF) and bypasses the per-handler
    # size cap. Reject anything not in [0, MAX_UPLOAD_BYTES].
    try:
        length = int(content_length)
    except (TypeError, ValueError):
        raise ValueError('Invalid Content-Length') from None
    if length < 0:
        raise ValueError('Invalid Content-Length (negative)')
    if length > _MAX_UPLOAD_BYTES:
        raise ValueError(f'Upload too large (max {_MAX_UPLOAD_BYTES} bytes)')
    raw = rfile.read(length)
    fields = {}
    files = {}
    delimiter = b'--' + boundary
    end_marker = b'--' + boundary + b'--'
    parts = raw.split(delimiter)
    for part in parts[1:]:
        stripped = part.lstrip(b'\r\n')
        if stripped.startswith(b'--'):
            break
        sep = b'\r\n\r\n' if b'\r\n\r\n' in part else b'\n\n'
        if sep not in part:
            continue
        header_raw, body = part.split(sep, 1)
        if body.endswith(b'\r\n'):
            body = body[:-2]
        elif body.endswith(b'\n'):
            body = body[:-1]
        header_text = header_raw.lstrip(b'\r\n').decode('utf-8', errors='replace')
        msg = _ep.HeaderParser().parsestr(header_text)
        disp = msg.get('Content-Disposition', '')
        name_m = _re.search(r'name="([^"]*)"', disp)
        file_m = _re.search(r'filename="([^"]*)"', disp)
        if not name_m:
            continue
        name = name_m.group(1)
        if file_m:
            files[name] = (file_m.group(1), body)
        else:
            fields[name] = body.decode('utf-8', errors='replace')
    return fields, files


def _sanitize_upload_name(filename: str) -> str:
    safe_name = _re.sub(r'[^\w.\-]', '_', Path(filename).name)[:200]
    if not safe_name or safe_name.strip('.') == '':
        raise ValueError('Invalid filename')
    return safe_name


def _attachment_root() -> Path:
    """Return the configured upload inbox root.

    Plain chat attachments are transient context for the agent, not project
    source files.  Keep them out of the active workspace by default while still
    allowing operators to move the inbox with HERMES_WEBUI_ATTACHMENT_DIR.
    """
    override = os.getenv('HERMES_WEBUI_ATTACHMENT_DIR', '').strip()
    if override:
        return Path(override).expanduser().resolve()
    return (STATE_DIR / 'attachments').resolve()


def _upload_destination(session_id: str, safe_name: str) -> Path:
    dest_dir = _session_attachment_dir(session_id)
    dest_dir.mkdir(parents=True, exist_ok=True)
    dest = (dest_dir / safe_name).resolve()
    if not dest.is_relative_to(dest_dir):
        raise ValueError('Invalid upload destination')
    if dest.exists():
        stem = dest.stem
        suffix = dest.suffix
        for idx in range(1, 1000):
            candidate = (dest_dir / f'{stem}-{idx}{suffix}').resolve()
            if not candidate.is_relative_to(dest_dir):
                raise ValueError('Invalid upload destination')
            if not candidate.exists():
                return candidate
        raise ValueError('Too many uploads with the same filename')
    return dest


def _session_attachment_dir(session_id: str, *, root: Path | None = None) -> Path:
    root = (root or _attachment_root()).resolve()
    dest_dir = (root / _re.sub(r'[^\w.\-]', '_', str(session_id or 'session'))[:120]).resolve()
    if not dest_dir.is_relative_to(root):
        raise ValueError('Invalid attachment directory')
    return dest_dir


def handle_upload(handler):
    import traceback as _tb
    try:
        content_type = handler.headers.get('Content-Type', '')
        content_length = int(handler.headers.get('Content-Length', 0) or 0)
        if content_length > MAX_UPLOAD_BYTES:
            return j(handler, {'error': f'File too large (max {MAX_UPLOAD_BYTES//1024//1024}MB)'}, status=413)
        fields, files = parse_multipart(handler.rfile, content_type, content_length)
        session_id = fields.get('session_id', '')
        if 'file' not in files:
            return j(handler, {'error': 'No file field in request'}, status=400)
        filename, file_bytes = files['file']
        if not filename:
            return j(handler, {'error': 'No filename in upload'}, status=400)
        try:
            s = get_session(session_id)
        except KeyError:
            return j(handler, {'error': 'Session not found'}, status=404)
        safe_name = _sanitize_upload_name(filename)
        dest = _upload_destination(session_id, safe_name)
        dest.write_bytes(file_bytes)
        mime = mimetypes.guess_type(safe_name)[0] or 'application/octet-stream'
        return j(handler, {
            'filename': dest.name,
            'path': str(dest),
            'size': dest.stat().st_size,
            'mime': mime,
            'is_image': mime.startswith('image/'),
        })
    except ValueError as e:
        return j(handler, {'error': str(e)}, status=400)
    except Exception:
        print('[webui] upload error: ' + _tb.format_exc(), flush=True)
        return j(handler, {'error': 'Upload failed'}, status=500)


def extract_archive(file_bytes: bytes, filename: str, workspace: Path):
    """Extract a zip or tar archive into the workspace.

    Returns a dict with ``extracted`` (int), ``files`` (list[str]).
    Raises ValueError on zip-slip or unsupported format.
    """
    import zipfile, tarfile, io, os, shutil

    cap = _max_extracted_bytes()
    name = Path(filename).name
    stem = Path(filename).stem  # strip .zip / .tar.gz etc.

    if name.lower().endswith(('.zip',)):
        _mode = 'zip'
    elif name.lower().endswith(('.tar', '.tar.gz', '.tgz', '.tar.bz2', '.tbz2', '.tar.xz', '.txz')):
        _mode = 'tar'
    else:
        raise ValueError(f'Unsupported archive format: {filename}')

    # Determine destination directory — use archive stem as folder name
    dest_dir = safe_resolve_ws(workspace, stem)
    # Avoid overwriting existing files by appending a suffix (bounded — astronomically
    # unlikely to collide, but never spin forever).
    if dest_dir.exists():
        import string, random
        for _ in range(1000):
            if not dest_dir.exists():
                break
            suffix = ''.join(random.choices(string.digits, k=3))
            dest_dir = safe_resolve_ws(workspace, stem).with_name(stem + '_' + suffix)
        else:
            raise ValueError('Could not allocate a unique extraction directory')
    dest_dir.mkdir(parents=True, exist_ok=True)

    # Member-count cap: a tiny archive with millions of (possibly empty) members
    # slips under the byte cap but can exhaust inodes / file descriptors. Bound it.
    _MAX_ARCHIVE_MEMBERS = 10000

    extracted_files = []
    total_extracted = 0

    try:
        if _mode == 'zip':
            with zipfile.ZipFile(io.BytesIO(file_bytes)) as zf:
                for member in zf.infolist():
                    # Skip directories
                    if member.is_dir():
                        continue
                    if len(extracted_files) >= _MAX_ARCHIVE_MEMBERS:
                        raise ValueError(
                            f'Archive has too many files (> {_MAX_ARCHIVE_MEMBERS}). '
                            f'Possible archive bomb.'
                        )
                    # Zip-slip protection
                    member_path = (dest_dir / member.filename).resolve()
                    if not member_path.is_relative_to(dest_dir.resolve()):
                        raise ValueError(f'Zip-slip blocked: {member.filename}')
                    # Zip-bomb protection: track actual extracted bytes (not declared file_size)
                    if total_extracted > cap:
                        raise ValueError(
                            f'Extraction too large ({total_extracted // (1024*1024)} MB > '
                            f'{cap // (1024*1024)} MB limit). '
                            f'Possible zip bomb.'
                        )
                    member_path.parent.mkdir(parents=True, exist_ok=True)
                    with zf.open(member) as src, open(member_path, 'wb') as dst:
                        _chunk_size = 65536
                        while True:
                            chunk = src.read(_chunk_size)
                            if not chunk:
                                break
                            total_extracted += len(chunk)
                            if total_extracted > cap:
                                raise ValueError(
                                    f'Extraction too large (> '
                                    f'{cap // (1024*1024)} MB limit). '
                                    f'Possible zip bomb.'
                                )
                            dst.write(chunk)
                    extracted_files.append(str(member_path.relative_to(workspace.resolve())))

        elif _mode == 'tar':
            with tarfile.open(fileobj=io.BytesIO(file_bytes)) as tf:
                for member in tf.getmembers():
                    if not member.isfile():
                        continue
                    if len(extracted_files) >= _MAX_ARCHIVE_MEMBERS:
                        raise ValueError(
                            f'Archive has too many files (> {_MAX_ARCHIVE_MEMBERS}). '
                            f'Possible archive bomb.'
                        )
                    # Tar-slip protection
                    member_path = (dest_dir / member.name).resolve()
                    if not member_path.is_relative_to(dest_dir.resolve()):
                        raise ValueError(f'Tar-slip blocked: {member.name}')
                    # Tar-bomb protection: track actual extracted bytes (not declared size)
                    if total_extracted > cap:
                        raise ValueError(
                            f'Extraction too large ({total_extracted // (1024*1024)} MB > '
                            f'{cap // (1024*1024)} MB limit). '
                            f'Possible zip bomb.'
                        )
                    member_path.parent.mkdir(parents=True, exist_ok=True)
                    src_obj = tf.extractfile(member)
                    if src_obj:
                        with src_obj as src, open(member_path, 'wb') as dst:
                            _chunk_size = 65536
                            while True:
                                chunk = src.read(_chunk_size)
                                if not chunk:
                                    break
                                total_extracted += len(chunk)
                                if total_extracted > cap:
                                    raise ValueError(
                                        f'Extraction too large (> '
                                        f'{cap // (1024*1024)} MB limit). '
                                        f'Possible zip bomb.'
                                    )
                                dst.write(chunk)
                    extracted_files.append(str(member_path.relative_to(workspace.resolve())))
    except Exception:
        # Clean up partially-extracted directory to avoid orphaned folders
        try:
            shutil.rmtree(dest_dir, ignore_errors=True)
        except Exception:
            pass
        raise

    return {'extracted': len(extracted_files), 'files': extracted_files, 'dest': str(dest_dir)}


def handle_upload_extract(handler):
    """Handle archive upload and extraction."""
    import traceback as _tb
    try:
        content_type = handler.headers.get('Content-Type', '')
        content_length = int(handler.headers.get('Content-Length', 0) or 0)
        if content_length > MAX_UPLOAD_BYTES:
            return j(handler, {'error': f'File too large (max {MAX_UPLOAD_BYTES//1024//1024}MB)'}, status=413)
        fields, files = parse_multipart(handler.rfile, content_type, content_length)
        session_id = fields.get('session_id', '')
        if 'file' not in files:
            return j(handler, {'error': 'No file field in request'}, status=400)
        filename, file_bytes = files['file']
        if not filename:
            return j(handler, {'error': 'No filename in upload'}, status=400)
        try:
            s = get_session(session_id)
        except KeyError:
            return j(handler, {'error': 'Session not found'}, status=404)
        session_dir = _session_attachment_dir(session_id)
        session_dir.mkdir(parents=True, exist_ok=True)
        result = extract_archive(file_bytes, filename, session_dir)
        return j(handler, {'ok': True, **result})
    except ValueError as e:
        return j(handler, {'error': str(e)}, status=400)
    except Exception:
        print('[webui] upload extract error: ' + _tb.format_exc(), flush=True)
        return j(handler, {'error': 'Archive extraction failed'}, status=500)


def handle_transcribe(handler):
    import traceback as _tb
    temp_path = None
    try:
        content_type = handler.headers.get('Content-Type', '')
        content_length = int(handler.headers.get('Content-Length', 0) or 0)
        if content_length > MAX_UPLOAD_BYTES:
            return j(handler, {'error': f'File too large (max {MAX_UPLOAD_BYTES//1024//1024}MB)'}, status=413)
        fields, files = parse_multipart(handler.rfile, content_type, content_length)
        if 'file' not in files:
            return j(handler, {'error': 'No file field in request'}, status=400)
        filename, file_bytes = files['file']
        if not filename:
            return j(handler, {'error': 'No filename in upload'}, status=400)
        safe_name = _sanitize_upload_name(filename)
        suffix = Path(safe_name).suffix or '.webm'
        with tempfile.NamedTemporaryFile(prefix='webui-stt-', suffix=suffix, delete=False) as tmp:
            temp_path = tmp.name
            tmp.write(file_bytes)
        try:
            from tools.transcription_tools import transcribe_audio
        except ImportError:
            return j(handler, {'error': 'Speech-to-text is unavailable on this server'}, status=503)
        result = transcribe_audio(temp_path)
        if not result.get('success'):
            msg = str(result.get('error') or 'Transcription failed')
            status = 503 if 'unavailable' in msg.lower() or 'not configured' in msg.lower() else 400
            return j(handler, {'error': msg}, status=status)
        transcript = str(result.get('transcript') or '').strip()
        return j(handler, {'ok': True, 'transcript': transcript})
    except ValueError as e:
        return j(handler, {'error': str(e)}, status=400)
    except Exception:
        print('[webui] transcribe error: ' + _tb.format_exc(), flush=True)
        return j(handler, {'error': 'Transcription failed'}, status=500)
    finally:
        if temp_path:
            try:
                Path(temp_path).unlink(missing_ok=True)
            except Exception:
                pass


def handle_workspace_upload(handler):
    """Upload a file into a session's workspace directory.

    Form fields:
        session_id – target session
        path       – subdirectory within the workspace (default: '')
    File:
        file – the uploaded file(s)
    """
    import traceback as _tb
    try:
        content_type = handler.headers.get('Content-Type', '')
        content_length = int(handler.headers.get('Content-Length', 0) or 0)
        if content_length > MAX_UPLOAD_BYTES:
            return j(handler, {'error': f'File too large (max {MAX_UPLOAD_BYTES//1024//1024}MB)'}, status=413)

        fields, files = parse_multipart(handler.rfile, content_type, content_length)
        session_id = fields.get('session_id', '')
        subpath = fields.get('path', '')

        if not session_id:
            return j(handler, {'error': 'Missing session_id'}, status=400)

        if not files:
            return j(handler, {'error': 'No file field in request'}, status=400)

        # Validate session
        try:
            session = get_session(session_id)
        except KeyError:
            return j(handler, {'error': 'Session not found'}, status=404)

        # Resolve workspace root from session
        workspace = resolve_trusted_workspace(session.workspace)

        # Resolve target subdirectory within workspace
        target_dir = safe_resolve_ws(workspace, subpath) if subpath else workspace
        # safe_resolve_ws intentionally permits in-workspace symlinks pointing
        # outside the root (read trust model). For an UPLOAD target that's not
        # acceptable: a planted symlink subpath would let mkdir() + writes create
        # files OUTSIDE the workspace. Require the resolved target to be inside
        # the workspace before creating anything. (is_relative_to is True for the
        # workspace==target equality case, so the normal subpath='' path passes.)
        if not target_dir.resolve().is_relative_to(workspace.resolve()):
            return j(handler, {'error': 'Upload target escapes workspace'}, status=403)
        target_dir.mkdir(parents=True, exist_ok=True)

        results = []
        for _field_name, (filename, file_bytes) in files.items():
            if not filename:
                continue

            safe_name = _sanitize_upload_name(filename)
            dest = safe_resolve_ws(target_dir, safe_name)

            # Path traversal guard (belt-and-suspenders: safe_resolve_ws above is
            # the authoritative guard and raises ValueError on traversal; this
            # check catches any edge case where the resolved path escapes).
            if not dest.resolve().is_relative_to(workspace.resolve()):
                return j(handler, {'error': f'Path traversal blocked: {safe_name}'}, status=403)

            # Deduplicate: append -1, -2, etc. if file already exists
            if dest.exists():
                stem = dest.stem
                suffix = dest.suffix
                for idx in range(1, 1000):
                    candidate = safe_resolve_ws(target_dir, f'{stem}-{idx}{suffix}')
                    if not candidate.resolve().is_relative_to(workspace.resolve()):
                        return j(handler, {'error': 'Path traversal blocked'}, status=403)
                    if not candidate.exists():
                        dest = candidate
                        break
                else:
                    return j(handler, {'error': 'Too many uploads with the same filename'}, status=400)

            dest.write_bytes(file_bytes)
            mime = mimetypes.guess_type(safe_name)[0] or 'application/octet-stream'

            # For archives, optionally extract into the target directory.
            # Suffix set MUST match extract_archive()'s supported formats, else
            # accepted-but-unlisted archives (.tar/.tbz2/.txz) silently land as
            # raw files instead of extracting.
            is_archive = safe_name.lower().endswith(('.zip', '.tar', '.tar.gz', '.tgz', '.tar.bz2', '.tbz2', '.tar.xz', '.txz'))
            if is_archive:
                import zipfile, tarfile, traceback as _extract_tb
                try:
                    extraction = extract_archive(file_bytes, safe_name, target_dir)
                    # Remove the archive file after successful extraction
                    dest.unlink(missing_ok=True)
                    results.append({
                        'filename': safe_name,
                        'path': str(extraction.get('dest', target_dir)),
                        'size': len(file_bytes),
                        'is_image': False,
                        'extracted': True,
                        'extracted_files': extraction.get('files', []),
                        'extracted_count': extraction.get('extracted', 0),
                    })
                    continue
                except (zipfile.BadZipFile, tarfile.TarError, ValueError) as e:
                    # Extraction failed — remove the archive file (no partial
                    # content left behind) and surface the error to the user.
                    dest.unlink(missing_ok=True)
                    print(f'[webui] workspace upload extract error: {e}', flush=True)
                    results.append({
                        'filename': safe_name,
                        'path': str(target_dir),
                        'size': len(file_bytes),
                        'mime': mime,
                        'is_image': False,
                        'extracted': False,
                        'extract_error': str(e) or 'Archive extraction failed',
                    })
                    continue
                except Exception:
                    print('[webui] workspace upload extract error: ' + _extract_tb.format_exc(), flush=True)
                    dest.unlink(missing_ok=True)
                    results.append({
                        'filename': safe_name,
                        'path': str(target_dir),
                        'size': len(file_bytes),
                        'mime': mime,
                        'is_image': False,
                        'extracted': False,
                        'extract_error': 'Archive extraction failed',
                    })
                    continue

            results.append({
                'filename': dest.name,
                'path': str(dest),
                'size': dest.stat().st_size,
                'mime': mime,
                'is_image': mime.startswith('image/'),
                'extracted': False,
            })

        if len(results) == 1:
            return j(handler, results[0])
        return j(handler, {'files': results, 'count': len(results)})
    except ValueError as e:
        return j(handler, {'error': str(e)}, status=400)
    except Exception:
        print('[webui] workspace upload error: ' + _tb.format_exc(), flush=True)
        return j(handler, {'error': 'Upload failed'}, status=500)