"""Fetch a sample of ALL LessWrong posts since START_DATE (no tag filter)
for use as a baseline corpus to compare against AI-tagged posts.

Pagination uses a `before` date cursor because the GraphQL endpoint caps
`offset` (skip) at ~2000.

Writes: data/lesswrong_all_posts.jsonl

Usage:
  python fetch_lesswrong_all.py [--max N]
"""
import argparse
import json
import os
import re
import sys
import time
from pathlib import Path
import requests

PROJECT_DIR = os.path.dirname(os.path.abspath(__file__))
sys.path.insert(0, PROJECT_DIR)
from config import START_DATE

API = "https://www.lesswrong.com/graphql"
OUT = Path(PROJECT_DIR) / "data" / "lesswrong_all_posts.jsonl"
MIN_WORDS = 200


def strip_html(html):
    text = re.sub(r"<[^>]+>", " ", html or "")
    for esc, raw in [("&nbsp;", " "), ("&amp;", "&"), ("&lt;", "<"),
                     ("&gt;", ">"), ("&quot;", '"'), ("&#39;", "'")]:
        text = text.replace(esc, raw)
    text = re.sub(r"\s+", " ", text)
    return text.strip()


def gql(query, variables=None):
    r = requests.post(API, json={"query": query, "variables": variables or {}}, timeout=60)
    r.raise_for_status()
    j = r.json()
    if "errors" in j:
        raise RuntimeError(f"GraphQL errors: {j['errors']}")
    return j["data"]


QUERY = """
query GetPosts($limit: Int, $before: String, $after: String) {
  posts(input: {terms: {view: "new", limit: $limit, before: $before, after: $after}}) {
    results {
      _id title slug postedAt baseScore author wordCount
      contents { html }
      tags { name }
      user { displayName }
    }
  }
}
"""


def fetch_all(max_posts=50000, batch=200):
    """Walk posts newest-first using a `before` cursor. Each batch sets
    `before` to one second prior to the oldest postedAt of the previous batch
    (to avoid re-fetching the boundary post)."""
    out = []
    seen = set()
    before = None  # first call: no upper bound -> get newest
    while len(out) < max_posts:
        variables = {"limit": batch, "after": START_DATE}
        if before is not None:
            variables["before"] = before
        data = gql(QUERY, variables)
        results = data.get("posts", {}).get("results", [])
        if not results:
            print("  no more results", flush=True)
            break

        new = [r for r in results if r.get("_id") and r["_id"] not in seen]
        for r in new:
            seen.add(r["_id"])
        out.extend(new)

        # Find the oldest postedAt in this batch to use as next cursor
        dates = [r.get("postedAt") for r in results if r.get("postedAt")]
        if not dates:
            print("  batch had no postedAt, stopping", flush=True)
            break
        oldest = min(dates)

        print(f"  fetched {len(out)} (oldest in batch={oldest[:19]}, new={len(new)})",
              flush=True)

        # If oldest is at/before START_DATE, we're done
        if oldest[:10] <= START_DATE:
            print(f"  reached START_DATE={START_DATE}", flush=True)
            break

        if len(new) == 0:
            # Cursor didn't advance -> nothing new came back; bail
            print("  no new posts in this batch, stopping", flush=True)
            break

        before = oldest  # next page = strictly older than this
        time.sleep(0.4)
    return out


def main():
    ap = argparse.ArgumentParser()
    ap.add_argument("--max", type=int, default=50000)
    args = ap.parse_args()

    OUT.parent.mkdir(parents=True, exist_ok=True)
    posts = fetch_all(args.max)
    kept = 0
    with open(OUT, "w") as f:
        for p in posts:
            pid = p.get("_id")
            body = strip_html((p.get("contents") or {}).get("html") or "")
            wc = p.get("wordCount") or len(body.split())
            if not pid or not body or wc < MIN_WORDS: continue
            f.write(json.dumps({
                "id": pid,
                "title": p.get("title"),
                "slug": p.get("slug"),
                "posted_at": p.get("postedAt"),
                "body": body,
                "word_count": wc,
                "tags": [t["name"] for t in (p.get("tags") or [])],
                "base_score": p.get("baseScore"),
                "author": (p.get("user") or {}).get("displayName") or p.get("author"),
            }) + "\n")
            kept += 1
    print(f"=== done: {kept} posts >={MIN_WORDS} words -> {OUT} ===", flush=True)


if __name__ == "__main__":
    main()