#!/usr/bin/env python3
"""
diffindex.py - case-insensitive package/entry diff between two mw4index manifests.

    python3 diffindex.py <A.tsv> <B.tsv> [labelA] [labelB]

Per package it prints:
  * name-set diff  - which source assets exist on each side (the reliable signal)
  * blob multiset  - stored-byte md5 counts, names ignored (a rough upper bound
                     on how much payload differs; see the caveat in mw4index.py)

Packages present on only one side are reported as A-ONLY / B-ONLY.
"""
import sys, collections


def load(path):
    names = collections.defaultdict(set)
    blobs = collections.defaultdict(collections.Counter)
    sizes = collections.defaultdict(dict)
    with open(path, encoding="latin-1") as fh:
        for line in fh:
            line = line.rstrip("\n")
            if not line:
                continue
            pkg, _rid, name, dlen, _rlen, h = line.split("\t")
            pkg = pkg.lower()
            key = name.lower().replace("\\", "/")
            names[pkg].add(key)
            blobs[pkg][h] += 1
            sizes[pkg][key] = int(dlen)
    return names, blobs, sizes


def main():
    if len(sys.argv) < 3:
        sys.exit(__doc__)
    la = sys.argv[3] if len(sys.argv) > 3 else "A"
    lb = sys.argv[4] if len(sys.argv) > 4 else "B"
    an, ab, asz = load(sys.argv[1])
    bn, bb, bsz = load(sys.argv[2])

    for pkg in sorted(set(an) | set(bn)):
        if pkg not in an:
            print(f"== {pkg}: {lb}-ONLY PACKAGE ({len(bn[pkg])} entries)")
            continue
        if pkg not in bn:
            print(f"== {pkg}: {la}-ONLY PACKAGE ({len(an[pkg])} entries)")
            continue
        aonly = sorted(an[pkg] - bn[pkg])
        bonly = sorted(bn[pkg] - an[pkg])
        shared = sum((ab[pkg] & bb[pkg]).values())
        print(f"== {pkg}: {la}={len(an[pkg])} {lb}={len(bn[pkg])} | "
              f"names: common={len(an[pkg] & bn[pkg])} {la}_only={len(aonly)} {lb}_only={len(bonly)} | "
              f"blobs: identical={shared} {la}_uniq={sum(ab[pkg].values()) - shared} "
              f"{lb}_uniq={sum(bb[pkg].values()) - shared}")
        for n in aonly:
            print(f"   +{la}  {n}  ({asz[pkg][n]}B)")
        for n in bonly:
            print(f"   -{lb}  {n}  ({bsz[pkg][n]}B)")


if __name__ == "__main__":
    main()