# app/services/telegram_service.py

import httpx
from app.core.biz_exception import BizLogicError
from app.schemas.telegram import TelegramIn


def _parse_slots_summary(availability_data):
    """
    availability:
    [
      { "date": "2025-01-05", "times": [] },
      { "date": "2025-01-06", "times": [{"time": "09:30"}] }
    ]
    """
    if not availability_data:
        return "No specific slots data."
    
    if not isinstance(availability_data, list):
        return str(availability_data)
        
    summaries = []
    # 限制显示天数，防止消息过长
    display_limit = 4 
    
    for day in availability_data[:display_limit]:
        date_str = day.get("date")
        
        times = day.get("times", [])
        
        if not times:
            # 修改点：即使没有具体时间，只要有日期条目，也显示为可用
            summaries.append(f"{date_str}")
        else:
            # 有具体时间的处理
            time_list = [t.get("time", "") for t in times[:5]]
            time_text = ", ".join(filter(None, time_list)) # 过滤空时间
            if len(times) > 5:
                time_text += f" (+{len(times) - 5})"
            summaries.append(f"{date_str}: {time_text}")
            
    if len(availability_data) > display_limit:
        summaries.append(f"(+{len(availability_data) - display_limit} more days)")
        
    return " | ".join(summaries)


def _get_display_meta(slot_snapshot):
    """
    Return dynamic header logic based on status.
    Goal: Put the most important info in the notification preview.
    """
    date_str = slot_snapshot.get("earliest_date")
    
    if slot_snapshot.get("availability_status") == 'Available':
        # Notification Preview: "🟢 UK London: 15 Jan 2024"
        emoji = "🟢"
        # If available, the DATE is the headline
        headline = f'{slot_snapshot.get("country")}, {slot_snapshot.get("city")}: {date_str}'
        color = "info" # Green for WeChat
    elif slot_snapshot.get("availability_status") == 'Waitlist':
        emoji = "🟡"
        headline = f'Waitlist: {slot_snapshot.get("country")}, {slot_snapshot.get("city")}'
        color = "warning" # Orange for WeChat
    else:
        emoji = "🔴"
        headline = f'No Slots: {slot_snapshot.get("country")}, {slot_snapshot.get("city")}'
        color = "comment" # Grey for WeChat
        
    return emoji, headline, color, date_str

class TelegramService:

    @staticmethod
    async def push_to_telegram(payload: TelegramIn):
        url = f"https://api.telegram.org/bot{payload.api_token}/sendMessage"

        body = {
            "chat_id": payload.chat_id,
            "text": payload.message,
            "parse_mode": "HTML",
        }

        async with httpx.AsyncClient(timeout=10) as client:
            resp = await client.post(url, json=body)

        if resp.status_code != 200:
            raise BizLogicError(
                f"Telegram push failed: {resp.status_code}, {resp.text}"
            )
            
    async def push_slot_snapshot(api_token: str, chat_id: str, slot_snapshot) -> str:
        emoji, headline, _, date_str = _get_display_meta(slot_snapshot)        
        # 解析详情
        slots_summary = _parse_slots_summary(slot_snapshot.get("availability"))
        
        # 处理可能的 None 值
        website = slot_snapshot.get("website") or "#"  # 如果没有网址，给一个空锚点
        # 格式化更新时间
        checked_at = slot_snapshot.get("snapshot_at", "")
        if "T" in str(updated_at):
             checked_at = str(checked_at).replace("T", " ")
        
        TEMPLATE = (
            "{emoji} <b>{headline}</b>\n"
            "──────────────────\n"
            "🛂 <b>Visa:</b> {visa_type}\n"
            "📅 <b>Earliest:</b> <code>{date_str}</code>\n"
            "📊 <b>Slots:</b> {slots_summary}\n"
            "──────────────────\n"
            "🔗 <a href='{website}'><b>Book Now ➜</b></a>\n\n"
            "🕒 <i>Checked at {checked_at}</i>"
        )

        content = TEMPLATE.format_map({
            "emoji": emoji,
            "headline": headline,
            "visa_type": slot_snapshot.get("visa_type", "N/A"),
            "date_str": date_str,
            "slots_summary": slots_summary,
            "website": website,
            "checked_at": checked_at,
        })
        
        url = f"https://api.telegram.org/bot{api_token}/sendMessage"

        body = {
            "chat_id": chat_id,
            "text": content,
            "parse_mode": "HTML",
        }

        async with httpx.AsyncClient(timeout=10) as client:
            resp = await client.post(url, json=body)

        if resp.status_code != 200:
            raise BizLogicError(
                f"Telegram push failed: {resp.status_code}, {resp.text}"
            )