services/line_message_builder.py

"""
LINE Flex Message builder — extracted from routers/line_webhook.py.

Builds rich Flex Message bubbles for stock prediction results.
"""

import logging
from typing import Optional

logger = logging.getLogger(__name__)

# Flex Message imports — wrapped so the module still loads on older SDK builds
try:
    from linebot.v3.messaging import (
        FlexMessage,
        FlexBubble,
        FlexBubbleStyles,
        FlexBlockStyle,
        FlexBox,
        FlexText,
        FlexSeparator,
        FlexButton,
        MessageAction,
        QuickReply,
        QuickReplyItem,
        TextMessage,
    )
    FLEX_AVAILABLE = True
except ImportError:
    FLEX_AVAILABLE = False


def prob_bar(prob: float, width: int = 10) -> str:
    """Return a text-based probability bar, e.g. '█████░░░░░ 72%'."""
    filled = round(prob * width)
    return "█" * filled + "░" * (width - filled) + f" {prob:.0%}"


def build_flex_prediction(
    name: str,
    stock_no: str,
    exchange: str,
    price_str: str,
    signal: str,
    confidence: str,
    buy_prob: float,
    sell_prob: float,
    change_pct: float,
    today_change_pct: Optional[float] = None,
    degraded: bool = False,
):
    """
    Build a LINE Flex Message bubble for a stock prediction result.
    Raises ImportError if FLEX_AVAILABLE is False — caller must handle.
    """
    if not FLEX_AVAILABLE:
        raise ImportError("Flex Message classes not available in this SDK version")

    # Header colour driven by signal
    header_colours = {"BUY": "#27ACB2", "SELL": "#FF6B35", "HOLD": "#888888"}
    header_bg = header_colours.get(signal, "#888888")

    signal_labels = {"BUY": "📈 買進", "SELL": "📉 賣出", "HOLD": "⏸ 觀望"}
    conf_labels   = {"HIGH": "高 ★★★", "MEDIUM": "中 ★★☆", "LOW": "低 ★☆☆"}

    signal_label = signal_labels.get(signal, signal)
    conf_label   = conf_labels.get(confidence, confidence)
    exch_str     = f"（{exchange}）" if exchange else ""
    bar_buy      = prob_bar(buy_prob)
    bar_sell     = prob_bar(sell_prob)
    change_str   = f"{change_pct:+.2f}%"

    # -- Header --
    header = FlexBox(
        layout="vertical",
        background_color=header_bg,
        padding_all="lg",
        contents=[
            FlexText(
                text=f"{name} {stock_no}{exch_str}",
                weight="bold",
                color="#FFFFFF",
                size="lg",
                wrap=True,
            ),
            FlexText(
                text="台股預測",
                color="#FFFFFFCC",
                size="xs",
            ),
        ],
    )

    # -- Body --
    today_change_row = []
    if today_change_pct is not None:
        tc_str = f"{today_change_pct:+.2f}%"
        tc_color = "#27ACB2" if today_change_pct >= 0 else "#FF6B35"
        today_change_row = [
            FlexBox(
                layout="horizontal",
                contents=[
                    FlexText(text="今日漲跌", color="#666666", size="sm", flex=2),
                    FlexText(text=tc_str, weight="bold", size="sm", flex=3, align="end", color=tc_color),
                ],
            ),
        ]

    body = FlexBox(
        layout="vertical",
        spacing="md",
        padding_all="lg",
        contents=[
            FlexBox(
                layout="horizontal",
                contents=[
                    FlexText(text="現價", color="#666666", size="sm", flex=2),
                    FlexText(text=price_str, weight="bold", size="sm", flex=3, align="end"),
                ],
            ),
            *today_change_row,
            FlexSeparator(),
            FlexBox(
                layout="horizontal",
                contents=[
                    FlexText(text="訊號", color="#666666", size="sm", flex=2),
                    FlexText(text=signal_label, weight="bold", size="sm", flex=3, align="end"),
                ],
            ),
            FlexBox(
                layout="horizontal",
                contents=[
                    FlexText(text="信心度", color="#666666", size="sm", flex=2),
                    FlexText(text=conf_label, size="sm", flex=3, align="end"),
                ],
            ),
            FlexSeparator(),
            FlexBox(
                layout="horizontal",
                contents=[
                    FlexText(text="買進", color="#27ACB2", size="sm", flex=2),
                    FlexText(text=bar_buy, size="sm", flex=5, align="end"),
                ],
            ),
            FlexBox(
                layout="horizontal",
                contents=[
                    FlexText(text="賣出", color="#FF6B35", size="sm", flex=2),
                    FlexText(text=bar_sell, size="sm", flex=5, align="end"),
                ],
            ),
            FlexSeparator(),
            FlexBox(
                layout="horizontal",
                contents=[
                    FlexText(text="預測5日漲跌", color="#666666", size="sm", flex=3),
                    FlexText(
                        text=change_str,
                        weight="bold",
                        size="sm",
                        flex=2,
                        align="end",
                        color="#27ACB2" if change_pct >= 0 else "#FF6B35",
                    ),
                ],
            ),
            FlexSeparator(),
            *(
                [FlexText(
                    text="⚠️ 資料較少，預測準確度可能較低",
                    color="#FF6B35",
                    size="xs",
                    wrap=True,
                )]
                if degraded else []
            ),
            FlexText(
                text="⚠️ 僅供參考，非投資建議",
                color="#AAAAAA",
                size="xxs",
                wrap=True,
            ),
        ],
    )

    # -- Footer --
    footer = FlexBox(
        layout="vertical",
        contents=[
            FlexButton(
                action=MessageAction(label="再查一支", text=stock_no),
                style="link",
                color="#27ACB2",
                height="sm",
            ),
        ],
    )

    bubble = FlexBubble(
        header=header,
        body=body,
        footer=footer,
        styles=FlexBubbleStyles(
            header=FlexBlockStyle(background_color=header_bg),
        ),
    )

    return FlexMessage(alt_text=f"{name} {stock_no} 預測結果", contents=bubble)


def build_quick_reply_menu(results: list[dict]):
    """Build a Quick Reply menu from search results (max 13 items)."""
    if not FLEX_AVAILABLE:
        raise ImportError("Quick Reply classes not available in this SDK version")

    items = []
    for r in results[:13]:
        label = f"{r['stock_no']} {r['name']}"[:20]  # LINE limit: 20 chars
        items.append(QuickReplyItem(action=MessageAction(label=label, text=r['stock_no'])))
    msg = TextMessage(text="找到以下股票，請選擇：")
    msg.quick_reply = QuickReply(items=items)
    return msg


def build_plain_text_prediction(
    name: str,
    stock_no: str,
    exchange: str,
    price_str: str,
    signal: str,
    confidence: str,
    buy_prob: float,
    sell_prob: float,
    change_pct: float,
    today_change_pct: Optional[float] = None,
    degraded: bool = False,
) -> str:
    """Build a plain-text fallback prediction reply."""
    signal_emoji = {"BUY": "📈 買進", "SELL": "📉 賣出", "HOLD": "⏸ 觀望"}
    conf_label   = {"HIGH": "高 ★★★", "MEDIUM": "中 ★★☆", "LOW": "低 ★☆☆"}
    exch_str     = f"（{exchange}）" if exchange else ""
    today_line   = f"今日漲跌：{today_change_pct:+.2f}%\n" if today_change_pct is not None else ""
    return (
        f"📊 {name} {stock_no}{exch_str}\n"
        f"現價：{price_str}\n"
        f"{today_line}"
        f"─────────────\n"
        f"訊號：{signal_emoji.get(signal, signal)}\n"
        f"信心度：{conf_label.get(confidence, confidence)}\n"
        f"買進機率：{buy_prob:.0%}　賣出：{sell_prob:.0%}\n"
        f"預測5日漲跌：{change_pct:+.2f}%\n"
        f"─────────────\n"
        + ("⚠️ 資料較少，預測準確度可能較低\n" if degraded else "")
        + f"⚠️ 僅供參考，非投資建議"
    )