"""Bounded conversational pagination over the server-validated customer scope."""

import re
import sqlite3

from .db import connect


def page_command(message):
    text=re.sub(r'[\s，,。.!！?？]','',message)
    match=re.fullmatch(r'(?:请)?(?:订单)?第(\d{1,5})页',text)
    if match:return int(match.group(1))
    if re.fullmatch(r'(?:请|继续)?(?:下一页|下页|继续显示|接着显示(?:剩下的)?订单)',text):return 'next'
    if re.fullmatch(r'(?:请)?(?:上一页|上页)',text):return 'previous'
    return None


def answer_list(message,tenants,conv_id=None):
    from .order_data import is_lookup_help,parse_count_query,tenant_filter,STATUS_LABELS
    from .customer_service import order_login_response

    command=page_command(message)
    initial=(not is_lookup_help(message) and re.search(r'订单|运单|\borders?\b|\bshipments?\b',message,re.I)
             and re.search(r'列出|列表|全部|所有|\blist\b',message,re.I))
    if command is None and not initial:return None
    if not tenants:return order_login_response()
    page=1;status=None
    if command is None:
        intent=parse_count_query(re.sub(r'列出|列表|全部|所有|\blist\b','多少',message,flags=re.I))
        if intent is None or intent['unsupported']:
            return {'t':'暂不支持按这个条件列出订单。可查看全部订单或按履约中、已完成等业务状态查询。'}
        status=intent['status']
    scope=tenant_filter(tenant_ids=tenants)
    if scope is None:return order_login_response()
    connection=None
    try:
        connection=connect()
        if command is not None:
            if not conv_id:return {'t':'请先在当前对话中发送“列出我的订单”，再翻页查看。'}
            prior=connection.execute("SELECT content FROM messages WHERE conv_id=? AND role='assistant' ORDER BY id DESC LIMIT 1",(conv_id,)).fetchone()
            header=prior[0].split('\n',1)[0] if prior else ''
            match=re.fullmatch(r'您当前的订单列表（.*第(\d+)页；业务状态：([^）]+)）：',header)
            if not match:return {'t':'请先在当前对话中发送“列出我的订单”，再翻页查看。'}
            labels={label:code for code,label in STATUS_LABELS.items()}
            status=labels.get(match[2])
            if match[2]!='全部' and status is None:return {'t':'请重新指定需要查看的订单状态。'}
            page=int(command) if isinstance(command,int) else max(1,int(match[1])+(1 if command=='next' else -1))
            if not 1<=page<=10000:return {'t':'请提供1至10000之间的有效页码。'}
        where=' WHERE 1=1'+scope[0];values=scope[1]
        if status:where+=' AND status=?';values=values+[status]
        # Both reads see one current snapshot and apply exactly the same scope/filter.
        connection.execute('BEGIN')
        total=connection.execute('SELECT COUNT(*) FROM order_test_data'+where,values).fetchone()[0]
        page=min(page,max(1,(total+19)//20))
        rows=connection.execute('SELECT order_no,inbound_code,status,warehouse_code FROM order_test_data'+where+
            ' ORDER BY id DESC LIMIT 20 OFFSET ?',values+[(page-1)*20]).fetchall()
        if not rows:return {'t':'当前账号下没有符合条件的订单。','_customer_data':True}
        label=STATUS_LABELS[status] if status else '全部'
        first='先列出20票；' if page==1 and total>20 else ''
        lines=[f'您当前的订单列表（{first}第{page}页；业务状态：{label}）：',f'共{total}票，当前显示第{(page-1)*20+1}至{(page-1)*20+len(rows)}票。']
        for number,inbound,business_status,warehouse in rows:
            lines.append(f'- 入仓码：{inbound or "未登记"}；订单号：{number}；业务状态：{STATUS_LABELS.get(business_status,business_status)}；目的仓：{warehouse or "未登记"}')
        lines.append('回复“下一页”查看后续订单。' if page*20<total else '当前已是最后一页。')
        lines.append('发送入仓码可查询该票订单和物流轨迹。')
        return {'t':'\n'.join(lines),'_customer_data':True}
    except sqlite3.Error:
        return {'t':'订单信息暂时无法读取，请稍后重试。'}
    finally:
        if connection is not None:connection.close()