import gzip
import zlib
import io
import struct
import sys
import tarfile
import json

def decompress(data):
    """Decompress a gzip compressed string in one shot.
    Return the list of decompressed sections.
    """
    while True:
        fp = io.BytesIO(data)
        if gzip._read_gzip_header(fp) is None:
            return
        # Use a zlib raw deflate compressor
        do = zlib.decompressobj(wbits=-zlib.MAX_WBITS)
        # Read all the data except the header
        decompressed = do.decompress(data[fp.tell():])
        if not do.eof or len(do.unused_data) < 8:
            raise EOFError("Compressed file ended before the end-of-stream "
                           "marker was reached")
        crc, length = struct.unpack("<II", do.unused_data[:8])
        if crc != zlib.crc32(decompressed):
            raise BadGzipFile("CRC check failed")
        if length != (len(decompressed) & 0xffffffff):
            raise BadGzipFile("Incorrect length of data produced")
        yield(decompressed)
        data = do.unused_data[8:].lstrip(b"\x00")

metadata = {}
with open(sys.argv[1], 'rb') as fin:
    for i, section in enumerate(decompress(fin.read())):
        if i != 1: # first section is signature, second is package metadata, third is package data
            continue
        sio = io.BytesIO(section)
        star = tarfile.TarFile(name=None, mode='r', fileobj=sio)
        for tarinfo in star:
            if tarinfo.name != '.PKGINFO':
                continue
            v = star.extractfile(tarinfo)
            v = v.read().decode('utf-8')
            for line in v.split("\n"):
                line = line.strip()
                if len(line) == 0:
                    continue
                if line[0] == '#':
                    continue
                parts = [part.strip() for part in line.split('=',1)]
                k = parts[0]
                entry = metadata.get(k)
                if entry is None:
                    entry = []
                entry.append(parts[1])
                metadata[k] = entry

json.dump(metadata, sys.stdout, indent=1)