"""Tool interfaces: search, fetch, extract.

- MockTools: scenario-driven, with failure injection (eval harness; no network).
- NetTools: optional real fetch of public pages via an network client; search is a fixed seed-URL stub
  (no scraping of search engines; wire official source APIs later if needed).
- extract_claims: LLM-free regex extractor with plausibility guards (default).
- Optional LLM extraction is wired through interfaces.LLMExtractor + providers.json (SQ_LLM_* env).
"""

from __future__ import annotations
import json
import math
import os
import re

from bounds import area_lower_bound, trivial_upper_bound


class ToolError(Exception):
    pass


class MockTools:
    """tools spec (from scenario JSON):
    {"search": [ {url, date, source_type, source_key?}, ... ] | "error",
     "search_fail_times": int,          # transient failures before success (-1 = always)
     "pages": {url: {"text": str, "fail_times": int, "error": str}}}"""

    def __init__(self, spec):
        self.spec = spec
        self.calls = {}

    def _maybe_fail(self, key, fail_times, err):
        k = self.calls.get(key, 0)
        self.calls[key] = k + 1
        if fail_times == -1 or k < fail_times:
            raise ToolError(f"{key}: {err}")

    def search(self, query):
        if self.spec.get("search") == "error":
            raise ToolError("search: status 503")
        self._maybe_fail("search", self.spec.get("search_fail_times", 0), "rate limited (429)")
        return list(self.spec.get("search", []))

    def fetch(self, url):
        page = self.spec.get("pages", {}).get(url)
        if page is None:
            raise ToolError(f"fetch {url}: 404")
        self._maybe_fail(url, page.get("fail_times", 0), page.get("error", "timeout"))
        if "text_file" in page:  # frozen real capture
            with open(page["text_file"], encoding="utf-8") as f:
                return f.read()
        return page.get("text", "")


class NetTools:
    """Real-network tools for manual runs. Search returns configured seed URLs only."""

    def __init__(self, seeds, timeout=20.0):
        self.seeds = seeds  # list of {url, date, source_type}
        self.timeout = timeout

    def search(self, query):
        return list(self.seeds)

    def fetch(self, url):
        import httpx  # optional dependency
        try:
            r = httpx.get(url, timeout=self.timeout, follow_redirects=True,
                          headers={"User-Agent": "squares-progress-agent/0.1"})
            r.raise_for_status()
        except Exception as e:  # network errors become ToolError for uniform handling
            raise ToolError(f"fetch {url}: {e}") from e
        text = re.sub(r"<script.*?</script>|<style.*?</style>", " ", r.text, flags=re.S | re.I)
        return re.sub(r"<[^>]+>", " ", text)


# ----------------------------------------------------------------- extraction
NUM = r"([0-9]+(?:[.,][0-9]+)?)"
REL = r"\s*(?:=|≈|~|:|is|≤|<=)\s*"
PATTERNS = [
    re.compile(r"\bs\s*\(\s*(\d{1,4})\s*\)" + REL + NUM),
    re.compile(r"\bn\s*=\s*(\d{1,4})\b[^\n]{0,60}?\b(?:s|L|side(?: length)?|container side)" + REL + NUM),
    re.compile(r"\b(\d{1,4})\s+(?:unit\s+)?squares?\b[^\n]{0,60}?\b(?:side|container)[^\n0-9]{0,30}?" + NUM),
]
TABLE_HEADER = re.compile(r"^\s*\|\s*n\s*\|\s*(?:s|side|L|best s)\s*\|", re.I)
TABLE_ROW = re.compile(r"^\s*\|\s*(\d{1,4})\s*\|\s*" + NUM + r"\s*\|")
SKIP_LINE = re.compile(r"\b(retract\w*|withdrawn|was wrong|was a bug|target|goal|hope|if we|would be)\b", re.I)
SCORE = re.compile(r"score\s*[=:]?\s*(-?[0-9]+\.[0-9]+)", re.I)
BLOCK = re.compile(r"```packing\s*\n(.*?)(?:```|\Z)", re.S)


def _num(v):
    return float(v.replace(",", "."))


TRUNC_AFTER = re.compile(r"^\s*(?:…|\.\.\.)")
APPROX_BEFORE = re.compile(r"(?:≈|~|approx\w*\.?)\s*$", re.I)


def display_uncertainty(line, start, end, raw):
    """Absolute uncertainty (container-side units) implied by how a number is printed.
    '2.707...' / '2.707…' (truncated) or '≈ 2.707' (rounded) -> 10**-decimals; otherwise 0."""
    dec = len(raw.replace(",", ".").split(".")[1]) if re.search(r"[.,]", raw) else 0
    if TRUNC_AFTER.match(line[end:]) or APPROX_BEFORE.search(line[max(0, start - 16):start]):
        return 10.0 ** -dec
    return 0.0


def extract_claims(text, meta):
    """Return (claims, notes). Each claim: n, s, coordinates_available, packing, score,
    source_url, source_type, source_key, date, extracted_text."""
    claims, notes = [], []
    base = {"source_url": meta["url"], "source_type": meta.get("source_type", "unknown"),
            "source_key": meta.get("source_key", meta["url"]), "date": meta.get("date", "")}

    def add(n, s, quote, packing=None, score=None, unc=0.0):
        if not 1 <= n <= 1000:
            notes.append(f"ignored n={n} (out of range)"); return
        if s is not None:
            if s < area_lower_bound(n) - 1e-9:
                notes.append(f"rejected n={n} s={s}: below area bound sqrt(n)={area_lower_bound(n):.6f}")
                claims.append({**base, "n": n, "s": s, "rejected": "impossible (area bound)",
                               "coordinates_available": packing is not None, "packing": packing,
                               "score": score, "extracted_text": quote[:160]})
                return
            if s > trivial_upper_bound(n) + 1e-9:
                notes.append(f"ignored n={n} s={s}: worse than trivial grid (likely noise)"); return
        claims.append({**base, "n": n, "s": s, "coordinates_available": packing is not None,
                       "packing": packing, "score": score, "s_uncertainty": unc, "extracted_text": quote[:160]})

    # 1) structured packing blocks (coordinates)
    for m in BLOCK.finditer(text):
        raw = m.group(1)
        try:
            d = json.loads(raw)
            n, side = int(d["n"]), d["side"]
            s = float(eval_side(side))
            add(n, s, raw[:160], packing=d)
        except Exception as e:  # truncated/malformed block -> partial observation
            notes.append(f"unparseable packing block ({type(e).__name__})")
    text_wo_blocks = BLOCK.sub(" ", text)

    # 2) line-level claims
    in_table = False
    seen = set()
    for line in text_wo_blocks.splitlines():
        if TABLE_HEADER.match(line):
            in_table = True; continue
        if in_table:
            m = TABLE_ROW.match(line)
            if m:
                key = (int(m.group(1)), _num(m.group(2)))
                if key not in seen:
                    seen.add(key); add(key[0], key[1], line.strip())
                continue
            if not line.strip().startswith("|"):
                in_table = False
        if SKIP_LINE.search(line):
            if any(p.search(line) for p in PATTERNS):
                notes.append(f"skipped hedged/retracted line: {line.strip()[:80]}")
            continue
        sc = SCORE.search(line)
        for p in PATTERNS:
            for m in p.finditer(line):
                key = (int(m.group(1)), _num(m.group(2)))
                if key in seen:
                    continue
                seen.add(key)
                add(key[0], key[1], line.strip(), score=float(sc.group(1)) if sc else None,
                    unc=display_uncertainty(line, m.start(2), m.end(2), m.group(2)))
    return claims, notes


def eval_side(side):
    """side may be a number or an exact string like '7/5'. Returns Fraction or float."""
    from fractions import Fraction
    if isinstance(side, str) and re.fullmatch(r"\s*-?\d+(?:/\d+)?\s*", side):
        return Fraction(side.strip())
    return float(side)


# LLM extraction lives in interfaces.LLMExtractor (same interface as the rule extractor).