diff-manifest

#!/usr/bin/env python3
import argparse
import json


def loadjson(fname: str):
    with open(fname, mode="r", encoding="utf-8") as jsonfile:
        return json.load(jsonfile)


def difflist(alist, blist):
    acopy = list(alist)
    for bv in blist:
        try:
            acopy.remove(bv)
        except ValueError:
            pass

    bcopy = list(blist)
    for av in alist:
        try:
            bcopy.remove(av)
        except ValueError:
            pass

    diff = {}
    if acopy:
        diff["a"] = acopy
    if bcopy:
        diff["b"] = bcopy
    return diff


def calcdiff(adata, bdata):
    diff = {}

    if adata == bdata:
        return diff

    if isinstance(adata, dict) and isinstance(bdata, dict):
        only_in_a = []
        for ak, av in adata.items():
            bv = bdata.get(ak)
            if bv is None:
                only_in_a.append({ak: av})
            kdiff = calcdiff(av, bv)
            if kdiff:
                diff[ak] = kdiff

        if only_in_a:
            diff["only-in-a"] = only_in_a

        # find keys that are only in b
        only_in_b = []
        for bk in bdata.keys():
            if adata.get(bk) is None:
                only_in_b.append({bk: bv})

        if only_in_b:
            diff["only-in-b"] = only_in_b
    elif isinstance(adata, list) and isinstance(bdata, list):
        diff.update(difflist(adata, bdata))
    else:
        diff["a"] = adata
        diff["b"] = bdata

    return diff


def describe(diff):
    # TODO: simplify and make it readable
    print(json.dumps(diff, indent=2))


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument("a")
    parser.add_argument("b")
    args = parser.parse_args()

    a = args.a
    b = args.b

    adata = loadjson(a)
    bdata = loadjson(b)

    diff_data = calcdiff(adata, bdata)
    describe(diff_data)


if __name__ == "__main__":
    main()