"""
Zero-token backfill:
  - Mark old posts with prefilter_reason (rt_only / url_only / empty) where applicable
  - Fill ai_reasoning for posts that have a signal but empty reasoning
  - Stamp analysis_version='legacy' on anything still missing it

Run once after the schema migration. Safe to re-run.
"""
from __future__ import annotations

import asyncio
import os
import sys
from typing import Optional

sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

from sqlalchemy import select

from app.database import AsyncSessionLocal
from app.models import Post


def classify(text: str) -> Optional[str]:
    stripped = (text or "").strip()
    if not stripped:
        return "empty"
    if stripped.startswith("RT: https://") and len(stripped) < 60:
        return "rt_only"
    if stripped.startswith("https://") and " " not in stripped:
        return "url_only"
    return None


PREFILTER_MSG = {
    "rt_only": "Pre-filtered: retweet with no added commentary.",
    "url_only": "Pre-filtered: bare URL with no text content.",
    "empty": "Pre-filtered: empty post body.",
}


async def main():
    async with AsyncSessionLocal() as db:
        posts = (await db.execute(select(Post))).scalars().all()

        pre = ai_fix = ver = 0
        for p in posts:
            reason = classify(p.text)
            if reason and not p.prefilter_reason:
                p.prefilter_reason = reason
                if not p.ai_reasoning:
                    p.ai_reasoning = PREFILTER_MSG[reason]
                    ai_fix += 1
                pre += 1

            # Any remaining signal'd post with empty reasoning: fill a minimal note
            if p.signal and not p.ai_reasoning:
                p.ai_reasoning = "(legacy) reasoning not recorded for this post."
                ai_fix += 1

            if not p.analysis_version:
                p.analysis_version = "legacy"
                ver += 1

        await db.commit()
        print(f"✅ prefilter_reason set on {pre} posts")
        print(f"✅ ai_reasoning filled on {ai_fix} posts")
        print(f"✅ analysis_version stamped 'legacy' on {ver} posts")


if __name__ == "__main__":
    asyncio.run(main())