#!/usr/bin/env python3
"""compare.py <ours.json> <oracle.json> [label]

Structural, type-aware comparison of two dump files (bool != int != float,
str != list). Prints OK or the first few differences; exit 1 on any
difference.
"""
import json
import sys

MAX_DIFFS = 8


def walk(a, b, path, diffs):
    if len(diffs) >= MAX_DIFFS:
        return
    if type(a) is not type(b):
        diffs.append(f"{path}: type {type(a).__name__} != {type(b).__name__} ({a!r} vs {b!r})")
        return
    if isinstance(a, dict):
        for k in sorted(set(a) | set(b)):
            if k not in a:
                diffs.append(f"{path}.{k}: missing in ours")
            elif k not in b:
                diffs.append(f"{path}.{k}: extra in ours")
            else:
                walk(a[k], b[k], f"{path}.{k}", diffs)
    elif isinstance(a, list):
        if len(a) != len(b):
            diffs.append(f"{path}: length {len(a)} != {len(b)}")
        for i, (x, y) in enumerate(zip(a, b)):
            walk(x, y, f"{path}[{i}]", diffs)
    elif a != b:
        diffs.append(f"{path}: {a!r} != {b!r}")


def main(argv):
    ours = json.load(open(argv[1], encoding="ascii"))
    oracle = json.load(open(argv[2], encoding="ascii"))
    label = argv[3] if len(argv) > 3 else argv[1]
    diffs = []
    walk(ours, oracle, "$", diffs)
    if diffs:
        print(f"DIFF {label}")
        for d in diffs:
            print("   ", d)
        return 1
    print(f"OK   {label}")
    return 0


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