#!/usr/bin/env python3
"""compare.py -- oracle check of the C++ walker against the reference reader.

usage: compare.py --reader SAVE_READER.py --saves DIR --dumps DIR [--python PY]

For every DIR/*.sav it runs `save_reader.py SAVE --dump --padding joint` and
reads the C++ dump written by test_save (`<name>.cpp.dump` in --dumps), then
reports two agreement figures per save:

  exact      lines identical (including the `?` guess marks and `(alt ...)`)
  canonical  lines identical after normalising what is presentation only:
             guess marks and alt readings dropped, 4-byte words compared by
             their raw bytes (an int reading and a float reading of the same
             word are the same datum), strings compared by content.

The typed summary (game name, turn, numSys, players) is compared as well.
Exit status 1 when any canonical line differs or a summary disagrees.
"""
import argparse
import ast
import glob
import json
import os
import re
import shlex
import struct
import subprocess
import sys

LINE = re.compile(r"^@([0-9a-f]{8}) (\s*)(\S+|) (\S+?)(\??) ?(.*)$")


def canon(line: str) -> str:
    m = LINE.match(line)
    if not m:
        return line
    off, indent, name, kind, _guess, rest = m.groups()
    rest = re.sub(r"\s+\(alt .*\)$", "", rest)
    if kind in ("int", "float"):
        try:
            raw = struct.pack("<i", int(rest)) if kind == "int" else struct.pack("<f", float(rest))
            return f"@{off} {indent}{name} word {raw.hex()}"
        except (ValueError, struct.error):
            pass
    return f"@{off} {indent}{name} {kind} {rest}"


def summary_of_reader(py, reader, save):
    out = subprocess.run([*shlex.split(py), reader, save, "--padding", "joint"], capture_output=True, text=True, check=True).stdout
    m = re.search(r"summary: game=(.*?) turn=(\d+) numSys=(\d+) players=(\d+)", out)
    return (ast.literal_eval(m.group(1)), int(m.group(2)), int(m.group(3)), int(m.group(4)))


def summary_of_cpp(path):
    txt = open(path, encoding="utf-8").read()
    m = re.search(r"summary: game=(\".*?\") turn=(\d+) numSys=(\d+) players=(\d+)", txt)
    return (json.loads(m.group(1)), int(m.group(2)), int(m.group(3)), int(m.group(4)))


def main():
    ap = argparse.ArgumentParser()
    ap.add_argument("--reader", required=True)
    ap.add_argument("--saves", required=True)
    ap.add_argument("--dumps", required=True)
    ap.add_argument("--python", default=sys.executable)
    a = ap.parse_args()
    bad = 0
    saves = sorted(glob.glob(os.path.join(a.saves, "*.sav")))
    if not saves:
        print("compare: no saves")
        return 0
    for save in saves:
        base = os.path.basename(save)
        cpp_dump = os.path.join(a.dumps, base + ".cpp.dump")
        if not os.path.exists(cpp_dump):
            print(f"{base}: no C++ dump at {cpp_dump}")
            bad += 1
            continue
        ref = subprocess.run([*shlex.split(a.python), a.reader, save, "--dump", "--padding", "joint"],
                             capture_output=True, text=True, check=True).stdout.splitlines()
        cpp = open(cpp_dump, encoding="utf-8").read().splitlines()
        n = max(len(ref), len(cpp))
        exact = sum(1 for x, y in zip(ref, cpp) if x == y)
        cref, ccpp = [canon(l) for l in ref], [canon(l) for l in cpp]
        canonical = sum(1 for x, y in zip(cref, ccpp) if x == y)
        first = next((i for i, (x, y) in enumerate(zip(cref, ccpp)) if x != y), None)
        rs = summary_of_reader(a.python, a.reader, save)
        cs = summary_of_cpp(os.path.join(a.dumps, base + ".cpp.summary"))
        ok = canonical == n and len(ref) == len(cpp) and rs == cs
        print(f"{base}: lines ref={len(ref)} cpp={len(cpp)}  exact {exact}/{n} ({100.0 * exact / n:.2f}%)  "
              f"canonical {canonical}/{n} ({100.0 * canonical / n:.2f}%)  summary {'agree' if rs == cs else 'DIFFER'}"
              f" {cs}")
        if first is not None:
            print(f"   first canonical difference at line {first + 1}:\n     ref: {ref[first]}\n     cpp: {cpp[first]}")
        if not ok:
            bad += 1
    print("compare:", "ok" if not bad else f"{bad} save(s) disagree")
    return 1 if bad else 0


if __name__ == "__main__":
    sys.exit(main())