from __future__ import annotations
import base64
import io
import logging
import re
import threading
import zipfile

import requests as _requests
from markupsafe import Markup, escape
from odoo import SUPERUSER_ID, api, registry as odoo_registry, models

_logger = logging.getLogger(__name__)

_HTML_TAG = re.compile(r'<[^>]+>')

# How many recent messages to scan when looking for a pending file upload
_LOOKBACK_MESSAGES = 10

# File type labels shown in the clarification message
_EXT_LABELS = {
    'jpg': 'image', 'jpeg': 'image', 'png': 'image', 'gif': 'image',
    'bmp': 'image', 'tiff': 'image', 'tif': 'image', 'webp': 'image',
    'pdf': 'PDF', 'html': 'HTML', 'htm': 'HTML',
    'txt': 'text', 'csv': 'spreadsheet', 'xlsx': 'spreadsheet',
    'zip': 'ZIP archive',
}


def _strip_html(html: str) -> str:
    return _HTML_TAG.sub(' ', html or '').strip()


def _ext(filename: str) -> str:
    return filename.rsplit('.', 1)[-1].lower() if '.' in filename else ''


def _text_to_html(text: str) -> Markup:
    """Convert plain text to HTML -- escapes content, turns newlines into <br>."""
    return Markup('<br>').join(Markup(escape(line)) for line in text.split('\n'))


def _describe_zip(datas_b64: str, zip_name: str) -> str:
    """Return a plain-text summary of a ZIP archive's contents."""
    try:
        raw = base64.b64decode(datas_b64)
        with zipfile.ZipFile(io.BytesIO(raw)) as zf:
            members = [m for m in zf.namelist() if not m.endswith('/')]
        if not members:
            return f'{zip_name} (empty archive)'
        counts: dict[str, int] = {}
        for m in members:
            label = _EXT_LABELS.get(_ext(m), 'file')
            counts[label] = counts.get(label, 0) + 1
        type_summary = ', '.join(f'{n} {t}(s)' for t, n in counts.items())
        lines = [f'{zip_name} -- {len(members)} item(s): {type_summary}']
        for m in members[:8]:
            lines.append(f'  - {m}')
        if len(members) > 8:
            lines.append(f'  ... and {len(members) - 8} more')
        return '\n'.join(lines)
    except Exception as exc:
        _logger.warning('_describe_zip failed for %s: %s', zip_name, exc)
        return f'{zip_name} (could not inspect contents)'


def _post_bot_reply(db: str, channel_id: int, bot_partner_id: int, reply_text: str):
    """Open a fresh DB cursor and post the bot reply to the channel."""
    try:
        with odoo_registry(db).cursor() as cr:
            env = api.Environment(cr, SUPERUSER_ID, {})
            env['discuss.channel'].browse(channel_id).sudo().message_post(
                body=_text_to_html(reply_text),
                author_id=bot_partner_id,
                message_type='comment',
                subtype_xmlid='mail.mt_comment',
            )
            cr.commit()
    except Exception as exc:
        _logger.error('_post_bot_reply failed channel=%s: %s', channel_id, exc)


def _agent_thread(db: str, uid: int, text: str, att_data: list,
                  bot_partner_id: int, channel_id: int,
                  bot_url: str, bot_secret: str):
    """
    Background thread: calls the agent service and posts the reply.
    Runs entirely outside the Odoo HTTP request so message_post returns
    immediately and the user sees their message without waiting for the LLM.
    """
    try:
        headers = {}
        if bot_secret:
            headers['X-ActiveBlue-Signature'] = bot_secret

        if att_data:
            files = [('files', (name, data, mime)) for name, data, mime in att_data]
            if not files:
                files = [('files', ('empty', b'', 'text/plain'))]
            form = {
                'user_id': str(uid),
                'message': text or 'Create an employee expense report from these receipts.',
                'session_id': '',
            }
            resp = _requests.post(bot_url + '/upload', data=form, files=files,
                                  headers=headers, timeout=600)
        else:
            payload = {'user_id': str(uid), 'message': text,
                       'context': {'source': 'discuss'}}
            headers['Content-Type'] = 'application/json'
            resp = _requests.post(bot_url + '/dispatch', json=payload,
                                  headers=headers, timeout=600)

        resp.raise_for_status()
        response = resp.json()
        reply_text = (response or {}).get('reply') or (response or {}).get('message') or \
                     'I could not process your request right now.'
    except _requests.exceptions.Timeout:
        reply_text = 'The request timed out. Please try again.'
    except _requests.exceptions.HTTPError as exc:
        # Try to surface the server-side error detail so the user knows what failed
        detail = ''
        try:
            detail = exc.response.json().get('detail') or ''
        except Exception:
            pass
        _logger.error('Agent HTTP error channel=%s status=%s: %s',
                      channel_id, exc.response.status_code if exc.response else '?', exc)
        if detail:
            reply_text = f'The agent returned an error: {detail}'
        else:
            reply_text = (f'The agent service returned an unexpected error '
                          f'(HTTP {exc.response.status_code if exc.response else "?"}). '
                          f'Please try again or contact your administrator.')
    except Exception as exc:
        _logger.error('Agent thread error channel=%s: %s', channel_id, exc)
        reply_text = f'I encountered an error: {exc}'

    _post_bot_reply(db, channel_id, bot_partner_id, reply_text)


class DiscussChannel(models.Model):
    _inherit = 'discuss.channel'

    @api.model
    def _ai_bot_partner(self):
        return self.env.ref('activeblue_ai.partner_activeblue_ai', raise_if_not_found=False)

    def message_post(self, *, body='', author_id=None, **kwargs):
        result = super().message_post(body=body, author_id=author_id, **kwargs)

        # Only intercept direct-message channels
        if self.channel_type != 'chat':
            return result

        bot_partner = self._ai_bot_partner()
        if not bot_partner:
            return result

        member_partners = self.channel_member_ids.partner_id
        if bot_partner not in member_partners:
            return result

        # Don't react to the bot's own messages
        if author_id == bot_partner.id:
            return result

        text = _strip_html(body)

        _logger.info(
            'AB AI mail hook: body=%r kwargs_keys=%s '
            'attachment_ids_kwarg=%r result.attachment_ids=%s',
            (body or '')[:80],
            list(kwargs.keys()),
            kwargs.get('attachment_ids'),
            result.attachment_ids.ids,
        )

        attachments = result.attachment_ids

        if not text and not attachments:
            return result

        # -- Case 1: file(s) with no instruction --------------------------------
        # Clarification is quick (no LLM) -- post inline, no thread needed.
        if attachments and not text:
            self._post_file_clarification(attachments, bot_partner)
            return result

        # -- Case 2: text (possibly with pending files from earlier upload) -----
        pending = self.env['ir.attachment'].browse()
        if text and not attachments:
            pending = self._find_pending_attachments(bot_partner)

        effective_attachments = attachments or pending

        human_partner = member_partners.filtered(lambda p: p != bot_partner)[:1]
        user = self.env['res.users'].search([('partner_id', '=', human_partner.id)], limit=1)
        uid = user.id if user else self.env.uid

        bot = self.env['ab.ai.bot'].sudo().search([('active', '=', True)], limit=1)
        if not bot:
            return result

        # Read everything we need from the DB NOW (current transaction) before
        # the background thread starts.  The thread must not touch ORM objects
        # from this transaction.
        db = self.env.cr.dbname
        bot_url = bot._get_service_url()
        bot_secret = bot.webhook_secret or ''
        channel_id = self.id
        bot_partner_id = bot_partner.id

        att_data: list[tuple[str, bytes, str]] = []
        for att in effective_attachments:
            try:
                data = base64.b64decode(att.datas) if att.datas else b''
                att_data.append((att.name or 'attachment', data,
                                 att.mimetype or 'application/octet-stream'))
            except Exception as exc:
                _logger.warning('Could not read attachment %s: %s', att.id, exc)

        # Launch the agent call in a daemon thread so this message_post returns
        # immediately -- the user sees their message without waiting for the LLM.
        threading.Thread(
            target=_agent_thread,
            args=(db, uid, text, att_data, bot_partner_id, channel_id,
                  bot_url, bot_secret),
            daemon=True,
        ).start()

        return result

    def _post_file_clarification(self, attachments, bot_partner):
        """Describe the uploaded file(s) and ask the user what to do with them."""
        file_lines = []
        for att in attachments:
            name = att.name or 'file'
            ext = _ext(name)
            if ext == 'zip' and att.datas:
                file_lines.append(_describe_zip(att.datas, name))
            else:
                label = _EXT_LABELS.get(ext, 'file')
                file_lines.append(f'{name} ({label})')

        file_summary = '\n'.join(file_lines)
        question = (
            f'I received the following file(s):\n'
            f'{file_summary}\n'
            f'\n'
            f'What would you like me to do with them? Some options:\n'
            f'  - Create an expense report from these receipts\n'
            f'  - Import products from this data\n'
            f'  - Something else -- just tell me what you need'
        )
        self.sudo().message_post(
            body=_text_to_html(question),
            author_id=bot_partner.id,
            message_type='comment',
            subtype_xmlid='mail.mt_comment',
        )

    def _find_pending_attachments(self, bot_partner):
        """
        Scan the last _LOOKBACK_MESSAGES messages in this channel for the most
        recent human-sent message that has attachments.  Only returns them if
        the immediately following bot message looks like a clarification question
        (i.e. the bot hasn't already acted on those files).
        """
        messages = self.message_ids.sorted('date', reverse=True)[:_LOOKBACK_MESSAGES]
        _bot_question_phrases = (
            'what would you like me to do',
            'suspected duplicate',
            'skip duplicates',
            'keep all',
            'please review',
            'reply "confirm"',
        )
        prev_was_bot_question = False
        for msg in messages:
            is_bot = msg.author_id == bot_partner
            if is_bot:
                body_lower = _strip_html(msg.body or '').lower()
                if any(p in body_lower for p in _bot_question_phrases):
                    prev_was_bot_question = True
                continue
            # Human message
            if msg.attachment_ids and prev_was_bot_question:
                return msg.attachment_ids
            prev_was_bot_question = False
        return self.env['ir.attachment'].browse()