services/llm.py

import os, json
from typing import List
from openai import AsyncOpenAI
from schemas import PostOut
from datetime import datetime, timedelta, timezone

OPENAI_API_KEY = os.getenv("OPENAI_API_KEY")
if not OPENAI_API_KEY:
    raise RuntimeError("OPENAI_API_KEY is required")

client = AsyncOpenAI(api_key=OPENAI_API_KEY)

async def summarize_trends_llm(items: List[dict], brand: str, language: str = "ja") -> str:
    """（既存）トレンド要約"""
    sys = "You are a marketing analyst. Summarize social trends succinctly with bullet points and actionable insights."
    lang = "日本語" if language == "ja" else "English"
    content = f"""Summarize the following social posts for {brand} in {lang}.
Return:
- Key themes (3-5 bullets)
- Opportunities (2-3 bullets)
- Risks (1-2 bullets)
- Suggested angles (3 bullets, ultra concise)

Posts JSON:
{items}
"""
    resp = await client.chat.completions.create(
        model="gpt-4o-mini",
        messages=[{"role":"system","content":sys},{"role":"user","content":content}],
        temperature=0.4,
    )
    return resp.choices[0].message.content.strip()

def _monday_start_utc(start_date_iso: str | None) -> datetime:
    if start_date_iso:
        base = datetime.fromisoformat(start_date_iso)
        if base.tzinfo is None:
            base = base.replace(tzinfo=timezone.utc)
        else:
            base = base.astimezone(timezone.utc)
    else:
        base = datetime.now(timezone.utc)
    # 月曜始まりにそろえる（0=Mon）
    delta = (base.weekday() + 7 - 0) % 7
    monday = (base - timedelta(days=delta)).replace(hour=0, minute=0, second=0, microsecond=0)
    return monday

def _iso_utc(dt: datetime) -> str:
    return dt.astimezone(timezone.utc).replace(microsecond=0).isoformat().replace("+00:00", "Z")

async def generate_week_plan_llm(
    brand: str,
    language: str,
    platforms: list[str],
    keywords: list[str],
    start_date: str | None,
    tone: str,
    cta: str,
    image_style_hint: str,
) -> List[PostOut]:
    """
    1週間分の『そのまま投稿できる』草案を厳密JSONで生成。
    - X: <=280 chars (目安<=270), 0-2 hashtags, 0-2 emojis, 日本語では自然な句読点
    - IG: 本文120-180字 + 改行 + 末尾に関連ハッシュタグ(最大8)。ハッシュタグは本文末尾に集約
    - URL/「http(s)://」等のプレースホルダは禁止。リンク案内は「プロフィールのリンクから」等で表現
    - バラエティ: 教育/価値, 製品/機能, UGC/お客様の声, 裏側, トレンド乗り を混在
    - 出力JSONスキーマ:
      {"posts":[{"platform":"x|instagram","text":"...","image_prompt":"..."} * 7 * len(platforms)]}
    """
    total_needed = 7 * max(1, len(platforms))
    lang = "日本語" if language == "ja" else "English"
    kw_text = ", ".join(keywords) if keywords else "N/A"

    sys = "You are a senior social media planner who writes ready-to-post copy."
    prompt = f"""
Write ready-to-post social content for brand "{brand}" in {lang}.
Requirements:
- Platforms to cover each day: {", ".join(platforms) if platforms else "x, instagram"}
- Tone: {tone}
- CTA to incorporate naturally (no URLs): {cta}
- Keywords to weave in lightly: {kw_text}
- No placeholders like [link], {{URL}}, or "http". Do not include external links.
- Emojis: 0-2 per post, only if they add clarity. Avoid spam.
- Hashtags: 
  * X: up to 2 short, relevant hashtags. Place at end.
  * Instagram: up to 8 relevant hashtags. Place at end on a new line.
- Brevity with specificity. Use numbers, proof-points, benefits, and micro-CTAs.
- Use natural Japanese if language is Japanese.

Return STRICT JSON with this exact schema (no extra keys, no comments):
{{
  "posts": [
    {{"platform":"x","text":"<X post (<=280 chars)>","image_prompt":"<Concise Canva brief>"}},
    {{"platform":"instagram","text":"<IG caption 120-180 chars + newline + hashtags>","image_prompt":"<Concise Canva brief>"}}
    // ... repeat until exactly {total_needed} items total (7 days × number of platforms), in day order
  ]
}}
"""

    # JSONモードで厳密JSONを要求
    resp = await client.chat.completions.create(
        model="gpt-4o-mini",
        response_format={"type": "json_object"},
        messages=[{"role":"system","content":sys},{"role":"user","content":prompt}],
        temperature=0.5,
    )

    # JSONパース
    try:
        data = json.loads(resp.choices[0].message.content)
        posts_json = data.get("posts", [])
    except Exception:
        posts_json = []

    # フォールバック: JSON不備なら簡易テンプレで埋める
    if not posts_json:
        for day in range(7):
            for plat in (platforms or ["x","instagram"]):
                if plat == "x":
                    posts_json.append({
                        "platform": "x",
                        "text": f"{brand} の新提案。{cta}｜詳細はプロフィールから #お知らせ",
                        "image_prompt": f"Canva: {brand} / X / {image_style_hint} / 見出し+要点3箇条"
                    })
                else:
                    posts_json.append({
                        "platform": "instagram",
                        "text": f"{brand} の最新情報。{cta}\n#お知らせ #{brand.replace(' ', '')}",
                        "image_prompt": f"Canva: {brand} / Instagram / {image_style_hint} / 正方形, 余白多め"
                    })

    # 7日分のUTCスケジュール自動割当（X=00:15Z, IG=01:00Z）
    start_monday_utc = _monday_start_utc(start_date)
    # JST 09:15→UTC 00:15, JST 10:00→UTC 01:00
    TIME_UTC = {"x": (0, 15), "instagram": (1, 0)}

    # 期待数に整形（多ければ切り、足りなければループで補充）
    need = 7 * (len(platforms) or 2)
    base_platforms = platforms or ["x", "instagram"]
    if len(posts_json) < need:
        # 足りない分は最後の要素を複製
        while len(posts_json) < need:
            posts_json.append(posts_json[-1])
    else:
        posts_json = posts_json[:need]

    # 並びを「日×プラットフォーム順」に調整（念のため）
    ordered = []
    idx = 0
    for day in range(7):
        for plat in base_platforms:
            item = posts_json[idx] if idx < len(posts_json) else {"platform": plat, "text": "", "image_prompt": ""}
            # プラットフォームが食い違っていたら上書き（文面は流用）
            item["platform"] = plat
            ordered.append(item)
            idx += 1

    # PostOut に変換＋scheduled_at 付与
    out: List[PostOut] = []
    for i, item in enumerate(ordered):
        day_idx = i // len(base_platforms)
        plat = item.get("platform", "x")
        hour_utc, min_utc = TIME_UTC.get(plat, (0, 30))
        dt = (start_monday_utc + timedelta(days=day_idx)).replace(hour=hour_utc, minute=min_utc, second=0, microsecond=0)
        scheduled_iso = _iso_utc(dt)

        out.append(PostOut(
            id=None,
            platform=plat,
            scheduled_at=scheduled_iso,
            text=item.get("text", "").strip(),
            image_prompt=item.get("image_prompt", "").strip(),
            status="draft",
        ))
    return out