#!/usr/bin/env python3
"""
treediff.py - case-insensitive loose-file diff of two directory trees.

    python3 treediff.py <dirA> <dirB> [labelA] [labelB]

Compares by relative path (lowercased, '/'-normalised) and md5. Written for the
hsh/, content/ and root config comparisons, where the two builds disagree on
filename case but not on identity.
"""
import sys, os, hashlib


def scan(root):
    out = {}
    for dirpath, _dirs, files in os.walk(root):
        for f in files:
            p = os.path.join(dirpath, f)
            rel = os.path.relpath(p, root).replace("\\", "/")
            with open(p, "rb") as fh:
                h = hashlib.md5(fh.read()).hexdigest()
            out[rel.lower()] = (os.path.getsize(p), h, rel)
    return out


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"
    a, b = scan(sys.argv[1]), scan(sys.argv[2])
    aonly = sorted(set(a) - set(b))
    bonly = sorted(set(b) - set(a))
    diff = sorted(k for k in set(a) & set(b) if a[k][1] != b[k][1])
    print(f"# {la}={len(a)} files, {lb}={len(b)} files | "
          f"identical={len(set(a) & set(b)) - len(diff)} differ={len(diff)} "
          f"{la}_only={len(aonly)} {lb}_only={len(bonly)}")
    for k in aonly:
        print(f"+{la}\t{a[k][2]}\t{a[k][0]}")
    for k in bonly:
        print(f"-{lb}\t{b[k][2]}\t{b[k][0]}")
    for k in diff:
        print(f"~DIF\t{a[k][2]}\t{la}={a[k][0]}B {lb}={b[k][0]}B")


if __name__ == "__main__":
    main()