examples: regex pre-filter (MONEY_RE + LOCATION_RE)

fire_planner/examples/filters.py

@@ -0,0 +1,64 @@
+"""Cheap regex pre-filter — keep posts that look like FIRE examples.
+
+A post survives if BOTH:
+  - it mentions money in a FIRE-relevant way (£/$/€, "net worth",
+    "portfolio", "million"), AND
+  - it mentions a location (country or major city).
+
+This prunes ~70–90 % of subreddit traffic before any LLM call. We
+deliberately err on the side of false-positives — the LLM is the
+expensive but reliable filter; this is the cheap pre-pass.
+"""
+from __future__ import annotations
+
+import re
+from functools import lru_cache
+
+from fire_planner.examples.models import RawPost
+
+MONEY_RE = re.compile(
+    r"(?:[£$€]\s?\d|"  # currency symbol + digit
+    r"\b(?:GBP|USD|EUR|JPY|AUD|CAD)\b|"
+    r"\bmillion\b|\bnet\s*worth\b|\bportfolio\b|\bsaved\b)",
+    re.IGNORECASE,
+)
+
+# Order matters: longer, less-ambiguous tokens first. List is curated to
+# cover the 12 target subs' typical countries/cities. Extend as needed.
+_LOCATION_KEYWORDS: list[str] = [
+    # countries
+    "philippines", "indonesia", "thailand", "vietnam", "malaysia",
+    "singapore", "japan", "korea", "taiwan", "india", "australia",
+    "new zealand", "canada", "united states", "usa", "uk", "ireland",
+    "scotland", "wales", "england", "spain", "portugal", "france",
+    "germany", "netherlands", "belgium", "italy", "greece", "cyprus",
+    "bulgaria", "romania", "poland", "czech", "hungary", "switzerland",
+    "austria", "denmark", "sweden", "norway", "finland", "estonia",
+    "uae", "dubai", "abu dhabi", "saudi", "qatar", "kuwait", "bahrain",
+    "mexico", "brazil", "argentina", "chile", "colombia", "peru",
+    "panama", "costa rica", "ecuador",
+    # cities common in expat-FIRE posts
+    "manila", "cebu", "bangkok", "chiang mai", "phuket", "ho chi minh",
+    "kuala lumpur", "penang", "bali", "jakarta", "tokyo", "osaka",
+    "lisbon", "porto", "madeira", "madrid", "barcelona", "valencia",
+    "limassol", "nicosia", "sofia", "athens", "berlin", "munich",
+    "amsterdam", "london", "edinburgh", "manchester", "dublin",
+    "sydney", "melbourne", "auckland", "vancouver", "toronto",
+    "mexico city", "buenos aires", "santiago",
+]
+
+LOCATION_RE = re.compile(
+    r"\b(" + "|".join(re.escape(k) for k in _LOCATION_KEYWORDS) + r")\b",
+    re.IGNORECASE,
+)
+
+
+@lru_cache(maxsize=1024)
+def _haystack(reddit_id: str, title: str, body: str) -> str:
+    return f"{title}\n{body}"
+
+
+def is_candidate(post: RawPost) -> bool:
+    """Return True when `post` is worth sending to the LLM."""
+    text = _haystack(post.reddit_id, post.title, post.body)
+    return bool(MONEY_RE.search(text) and LOCATION_RE.search(text))

tests/test_examples_filters.py

@@ -8,6 +8,7 @@ import pytest
 from pydantic import ValidationError
 
 from fire_planner.examples import ExtractedExample, FiStatus, RawPost, SummaryStats
+from fire_planner.examples.filters import is_candidate
 
 
 def test_raw_post_minimal() -> None:
@@ -44,3 +45,38 @@ def test_extracted_example_fi_status_enum() -> None:
 def test_summary_stats_optional_fields() -> None:
     s = SummaryStats(median=None, p25=None, p75=None)
     assert s.median is None
+
+
+def _post(title: str, body: str = "") -> RawPost:
+    return RawPost(
+        reddit_id="x",
+        source_sub="s",
+        url="u",
+        title=title,
+        body=body,
+        created_at=date(2026, 1, 1),
+    )
+
+
+def test_filter_keeps_money_plus_location() -> None:
+    assert is_candidate(_post("Hit £1m living in Lisbon, Portugal"))
+
+
+def test_filter_drops_money_without_location() -> None:
+    assert not is_candidate(_post("Hit £1m, feels great!"))
+
+
+def test_filter_drops_location_without_money() -> None:
+    assert not is_candidate(_post("Moving to Lisbon next year"))
+
+
+def test_filter_dollar_signs_count() -> None:
+    assert is_candidate(_post("$1.2M net worth, retired in Chiang Mai"))
+
+
+def test_filter_recognises_net_worth_keyword() -> None:
+    assert is_candidate(_post("Net worth update — now in Bali, Indonesia"))
+
+
+def test_filter_keyword_match_is_case_insensitive() -> None:
+    assert is_candidate(_post("PORTFOLIO milestone reached, settled in PHILIPPINES"))