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

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


def parse_multipart(rfile, content_type, content_length) -> tuple:
    import re as _re, email.parser as _ep
    m = _re.search(r'boundary=([^;\s]+)', content_type)
    if not m:
        raise ValueError('No boundary in Content-Type')
    boundary = m.group(1).strip('"').encode()
    raw = rfile.read(content_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 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)
        workspace = Path(s.workspace)
        safe_name = _sanitize_upload_name(filename)
        dest = safe_resolve_ws(workspace, safe_name)
        dest.write_bytes(file_bytes)
        return j(handler, {'filename': safe_name, 'path': str(dest), 'size': dest.stat().st_size})
    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 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