#!/usr/bin/env python3

from aptsources.sourceslist import SourcesList, Deb822SourceEntry
import apt_pkg
import glob
import os.path
import sys
import os


def main(rootfs):
    sources = SourcesList(False, deb822=True)

    dbglvl = os.environ.get("MMDEBSTRAP_VERBOSITY", "-1")
    try:
        dbglvl = int(dbglvl)
    except ValueError:
        dbglvl = -1
    if dbglvl >= 2:
        print("before:", file=sys.stderr)
        for s in sources.list:
            print(s.str(), end="", file=sys.stderr)

    os.makedirs(rootfs + "/etc/apt/sources.list.d", exist_ok=True)

    # remove all the things we do not want and change components and uri
    for s in list(sources):
        # since we put everything into a single output file, only one-line
        # format is supported for now
        assert not isinstance(s, Deb822SourceEntry), s
        s.file = rootfs + s.file
        # if it's a local file:// repo, don't mangle it
        if s.uri.startswith("file://"):
            continue
        # remove debug packages
        if s.uri.endswith("/debian-debug"):
            sources.remove(s)
            continue
        # only allow main
        s.comps = [c for c in s.comps if c in ["main"]]
        # remove sources with empty components list
        if not s.comps:
            sources.remove(s)
            continue
        # remove deb-src entries
        if s.type == "deb-src":
            sources.remove(s)
            continue
        # translate uri to our proxy on 127.0.0.1
        s.uri = "http://127.0.0.1/debian"

    # remove duplicates
    # we cannot use set() because order must be preserved
    seen = set()
    for s in list(sources):
        if s.str() in seen:
            sources.remove(s)
            continue
        seen.add(s.str())

    if dbglvl >= 2:
        print("after:", file=sys.stderr)
        for s in sources.list:
            print(s.str(), end="", file=sys.stderr)

    # we want to append to existing files, so backup the files which would
    # otherwise be overwritten by sources.save()
    files_to_backup = {}
    for s in sources.list:
        if os.path.isfile(s.file):
            files_to_backup[s.file] = b""

    for fname in files_to_backup:
        with open(fname, "rb") as f:
            files_to_backup[fname] = f.read()

    sources.save()

    # now prepend the original content
    for fname in files_to_backup:
        with open(fname, "rb") as f:
            updated_content = f.read()
        with open(fname, "wb") as f:
            f.write(files_to_backup[fname] + b"\n" + updated_content)

    # append apt preferences verbatim
    for pref in glob.glob("/etc/apt/preferences.d/*"):
        if not os.path.isfile(pref):
            continue
        os.makedirs(os.path.dirname(rootfs + pref), exist_ok=True)
        with open(pref) as fin, open(rootfs + pref, "a") as fout:
            fout.write("\n")
            for line in fin:
                fout.write(line)


if __name__ == "__main__":
    main(sys.argv[1])