#!/usr/bin/env python3
"""Build a Preferences-DataStore protobuf for the vojo proxy app from a ProxyState
JSON on stdin; emit it base64-encoded on stdout (pipe through `base64 -d` via run-as).

Wire layout (androidx.datastore.preferences):
  PreferenceMap.preferences = field 1 (map) -> entry{ key=field1 string, value=field2 Value }
  Value.string              = field 5
"""
import sys
import base64


def varint(n):
    out = bytearray()
    while True:
        b = n & 0x7F
        n >>= 7
        if n:
            out.append(b | 0x80)
        else:
            out.append(b)
            return bytes(out)


def ld(field, data):  # length-delimited field: tag=(field<<3)|2
    return bytes([(field << 3) | 2]) + varint(len(data)) + data


def main():
    state_json = sys.stdin.read().strip().encode("utf-8")
    value_msg = ld(5, state_json)                       # Value.string
    entry = ld(1, b"state") + ld(2, value_msg)          # entry: key + Value
    pref_map = ld(1, entry)                             # PreferenceMap.preferences
    sys.stdout.write(base64.b64encode(pref_map).decode())


if __name__ == "__main__":
    main()