"""Compose knowledge, freight and model output into the existing SSE protocol."""

import json
import re

from . import ai_client
from .ai_client import compress_answer, gen_followups, has_chinese
from .config import get_setting
from .db import connect, last_user_question, load_context, save_message
from .knowledge import search_knowledge
from .pricing import (parse_shipping_intent, detect_dim_unit, freight_reply,
                      calc_warehouse_card, detect_surcharge, surcharge_reply, check_island)
from .tracking import CARD_PREFIX, extract_tracking_no, build_track



def sse(payload):
    """统一的事件格式：data: {"t":正文} / {"e":错误} / {"card":卡片} / {"d":1结束}
    JSON 编码可以避免正文里的换行把 SSE 帧撑断。"""
    return 'data: ' + json.dumps(payload, ensure_ascii=False) + '\n\n'


def create_chat_stream(msg, conv_id):
    if not msg:
        return (sse({'e': '问题不能为空'}), {})
    if '[图片]' in msg and len(msg) < 300:
        return (sse({'t': '收到您的图片，请描述一下您的问题。'}) + sse({'d': 1}), {})
    track_no = extract_tracking_no(re.sub(r'\[(?:图片|文件)\]/uploads/\S+', '', msg))
    if track_no:
        card = build_track(track_no)

        def track_stream():
            save_message(conv_id, 'user', msg)
            yield sse({'card': card})
            save_message(conv_id, 'assistant', CARD_PREFIX + json.dumps(card, ensure_ascii=False))
            yield sse({'d': 1})
        return (track_stream(), {'Cache-Control': 'no-cache', 'X-Accel-Buffering': 'no'})
    if not get_setting('DEEPSEEK_API_KEY'):
        return (sse({'e': '服务未配置 API Key，请在 .env 或环境变量中设置 DEEPSEEK_API_KEY 后重启服务'}), {})
    know_text = search_knowledge(msg)
    ship = parse_shipping_intent(msg)
    ship['dim_unit'] = detect_dim_unit(msg)
    freight_text = None
    if not ship['weight'] and (not ship['dims']) and ship['channel']:
        prev_q = last_user_question(conv_id)
        if prev_q:
            prev_ship = parse_shipping_intent(prev_q)
            if prev_ship['weight'] or prev_ship['dims']:
                ship['weight'] = prev_ship['weight']
                ship['dims'] = prev_ship['dims']
                ship['dim_unit'] = detect_dim_unit(prev_q)
    if ship['weight'] or ship['dims']:
        if re.search('英国|UK|伦敦|英格兰', msg, re.I):
            uk_map = {'sea': 'sea_uk', 'rail': 'rail_uk', 'truck': 'truck_uk', 'air': 'air_uk'}
            ship['channel'] = uk_map.get(ship['channel'])
        freight_text = freight_reply(ship)
        if not ship['channel']:
            freight_text += '\n\n（客户没有指定渠道，上面已同时给出海运和空运，请在回答末尾询问更看重时效还是成本）'
    extra_parts = []
    cbm_m = re.search('(\\d+(?:\\.\\d+)?)\\s*(?:cbm|方|立方)', msg, re.I)
    if cbm_m:
        cbm = float(cbm_m.group(1))
        ch = '海运'
        if re.search('卡航|卡车', msg):
            ch = '卡航'
        elif re.search('铁路|班列', msg):
            ch = '铁路'
        elif re.search('普卡', msg):
            ch = '普卡'
        want = None
        for kw, ctry in (('德国', 'DE'), ('法国', 'FR'), ('波兰', 'PL'), ('捷克', 'CZ'), ('西班牙', 'ES'), ('马德里', 'ES'), ('中国', '')):
            if kw in msg:
                want = ctry
                break
        card = calc_warehouse_card(cbm, ch, country=want)
        if card:
            store = card['warehouse'].splitlines()[0]
            extra_parts.append(f"【海外仓卡派 · 按方计费】\n  仓点：{store}\n  计费：{card['note']}\n  渠道：{card['channel']}，适用档位 {card['tier']}\n  运费：{card['formula']}\n  说明：单箱实重超 35KG 加收 30 元/箱（封顶 3600 元）；不接受仓储，特殊情况 85 元/箱/周")
    sur = detect_surcharge(msg)
    if sur:
        extra_parts.append(surcharge_reply(sur[0], sur[1], ship.get('weight')))
    pc_m = re.search('(?<![0-9])(\\d{4,5})(?![0-9])', msg)
    if pc_m and re.search('邮编|postcode|zip|偏远|岛屿', msg, re.I):
        hit = check_island(pc_m.group(1))
        if hit:
            extra_parts.append(f'【偏远判断】邮编 {pc_m.group(1)} 属于{hit[0]}（{hit[1]}）的岛屿/偏远地区，需加收 DPD 岛屿附加费 35 欧元/件')
        else:
            extra_parts.append(f'【偏远判断】邮编 {pc_m.group(1)} 未命中 DPD 岛屿偏远清单；但仍需以 UPS/DPD 官网查询结果为准，偏远费以账单为准')
    follow_src = None
    if not know_text:
        prev_q = last_user_question(conv_id)
        if prev_q:
            know_text = search_knowledge(prev_q)
            if know_text:
                follow_src = prev_q
    _c = connect()
    _msg_count = _c.execute("SELECT COUNT(*) FROM messages WHERE conv_id=? AND role='user'", (conv_id,)).fetchone()[0]
    _c.close()
    is_first_turn = _msg_count == 0
    save_message(conv_id, 'user', msg)
    LENGTH_RULE = '回答长度要求：全文不少于 120 字、不超过 350 字。内容要完整、信息充分，把关键点讲清楚，可分 2~4 段或用短列表呈现。可以补充相关的说明（例如适用范围、注意事项、下一步建议），让对方看完就能明白。不要寒暄客套，不要重复同一个数字，不要罗列与问题无关的信息。'
    is_en = bool(re.search('[A-Za-z]{3,}', msg)) and (not re.search('[\\u4e00-\\u9fa5]', msg))
    if is_en:
        LANGUAGE_RULE = '【语言要求 · 最高优先级】用户用英文提问，你必须用英文（English）回答全文，包括所有小节标题（如 Conclusion / Calculation / Notes），不要出现任何中文。以下给出的中文结构与参考资料仅用于理解，输出必须翻译成英文。'
    else:
        LANGUAGE_RULE = '【语言要求】用户用中文提问，请用中文回答。'
    if freight_text or extra_parts:
        blocks = []
        if freight_text:
            blocks.append(freight_text)
        blocks.extend(extra_parts)
        body = '\n\n'.join(blocks)
        system_prompt = f'{LANGUAGE_RULE}\n\n你是柏悦物流智能客服。\n下面是根据报价表计算好的结果，请严格按照这些数字向客户说明。\n不要重新计算、不要改动任何数字，但要讲清楚是怎么算出来的。\n\n{body}\n\n请按以下结构输出（用英文回答时请把标题也翻译成英文）：\n【结论】先给结论：哪种方式、多少钱、多久到。\n【计算过程】分点列出，最多 5 行，让客户看懂钱花在哪。\n【补充说明】2~3 行：适用范围（如单件重量、尺寸要求）、偏远地区或敏感货附加费、下一步建议（如提供仓点或运单号可进一步核算）。\n\n{LENGTH_RULE}\n客户没指定渠道时，把主要几种渠道（海运/铁路/卡航/空运）列出来对比，并问客户更看重时效还是成本。\n'
    elif know_text:
        extra = f'\n（以上资料对应上一句提问：{follow_src}）' if follow_src else ''
        system_prompt = f'{LANGUAGE_RULE}\n\n你是柏悦物流智能客服，严格优先使用下面知识库内容回答，不要自己编造业务信息。\n回答语句通顺自然，分段清晰，让人一眼看清重点。\n要结合上文理解用户的追问（比如"那空运呢""这个多少钱"指的是什么）。\n\n{LENGTH_RULE}\n\n知识库内容（供你理解，输出需按语言要求翻译）：{know_text}{extra}\n'
    else:
        system_prompt = f'{LANGUAGE_RULE}\n\n你是柏悦物流智能客服。\n物流相关简单问题可以正常回答；不属于物流业务的问题礼貌说明无法解答，并建议联系人工客服。\n回答语句通顺，表述自然。\n\n{LENGTH_RULE}\n如果用户在追问，请结合上文的对话继续回答，不要重复问已经说过的信息。\n'
    context = load_context(conv_id, msg)

    def generate():
        body = {'model': get_setting('MODEL_NAME'), 'messages': [{'role': 'system', 'content': system_prompt}] + context, 'stream': True}
        try:
            resp = ai_client.post_completion(body, stream=True, timeout=(5, 90))
        except ai_client.Timeout:
            yield sse({'e': '模型响应超时，请稍后重试'})
            return
        except ai_client.RequestException:
            yield sse({'e': '无法连接模型服务，请检查网络后重试'})
            return
        except Exception:
            yield sse({'e': '服务异常，请稍后重试'})
            return
        if resp.status_code != 200:
            detail = ''
            try:
                detail = (resp.json().get('error') or {}).get('message', '')
            except Exception:
                detail = (resp.text or '')[:120]
            tips = {401: '系统繁忙，请稍后再试', 402: '系统繁忙，请稍后再试', 429: '咨询量较大，请稍后再试'}
            tip = tips.get(resp.status_code, '系统繁忙，请稍后再试')
            resp.close()
            yield sse({'e': tip})
            return
        parts = []
        interrupted = False
        try:
            got_text = False
            for raw in resp.iter_lines():
                if not raw:
                    continue
                line = raw.decode('utf-8', errors='ignore')
                if not line.startswith('data:'):
                    continue
                data = line[5:].strip()
                if data == '[DONE]':
                    break
                try:
                    j = json.loads(data)
                    chunk = j['choices'][0]['delta'].get('content') or ''
                except Exception:
                    continue
                if chunk:
                    got_text = True
                    parts.append(chunk)
                    yield sse({'t': chunk})
            if not got_text:
                yield sse({'e': '模型没有返回内容，请重试'})
                return
            full_text = ''.join(parts)
            limit = get_setting('MAX_ANSWER_CHARS') if has_chinese(full_text) else get_setting('MAX_ANSWER_CHARS_EN')
            if len(full_text) > limit:
                short = compress_answer(full_text, limit)
                if len(short) > limit:
                    short = compress_answer(short, limit - 60)
                if short != full_text:
                    full_text = short
                    yield sse({'replace': short})
            save_message(conv_id, 'assistant', full_text)
            if is_first_turn:
                try:
                    fu = gen_followups(msg, full_text)
                    if fu:
                        yield sse({'suggest': fu})
                except Exception:
                    pass
            yield sse({'d': 1})
        except GeneratorExit:
            interrupted = True
            raise
        except Exception:
            interrupted = True
            yield sse({'e': '传输中断，请点击重试'})
        finally:
            text = ''.join(parts)
            if interrupted and len(text) >= 20:
                save_message(conv_id, 'assistant', text + '\n\n（回答中断，以上内容未生成完整）')
            resp.close()
    return (generate(), {'Cache-Control': 'no-cache', 'X-Accel-Buffering': 'no'})