#!/usr/bin/python3

import datetime
import dnf
import hashlib
import json
import sys

DNF_ERROR_EXIT_CODE = 10


def timestamp_to_rfc3339(timestamp):
    d = datetime.datetime.utcfromtimestamp(package.buildtime)
    return d.strftime('%Y-%m-%dT%H:%M:%SZ')


def dnfrepo(desc, parent_conf=None):
    """Makes a dnf.repo.Repo out of a JSON repository description"""

    repo = dnf.repo.Repo(desc["id"], parent_conf)
    repo.name = desc["name"]

    if "baseurl" in desc:
        repo.baseurl = desc["baseurl"]
    elif "metalink" in desc:
        repo.metalink = desc["metalink"]
    elif "mirrorlist" in desc:
        repo.mirrorlist = desc["mirrorlist"]
    else:
        assert False

    if desc.get("ignoressl", False):
        repo.sslverify = False

    return repo


def create_base(repos):
    base = dnf.Base()

    for repo in repos:
        base.repos.add(dnfrepo(repo, base.conf))

    base.fill_sack(load_system_repo=False)
    return base


def exit_with_dnf_error(kind: str, reason: str):
    json.dump({"kind": kind, "reason": reason}, sys.stdout)
    sys.exit(DNF_ERROR_EXIT_CODE)


def repo_checksums(base):
    checksums = {}
    for repo in base.repos.iter_enabled():
        # Uses the same algorithm as libdnf to find cache dir:
        #   https://github.com/rpm-software-management/libdnf/blob/master/libdnf/repo/Repo.cpp#L1288
        if repo.metalink:
            url = repo.metalink
        elif repo.mirrorlist:
            url = repo.mirrorlist
        elif repo.baseurl:
            url = repo.baseurl[0]
        else:
            assert False

        digest = hashlib.sha256(url.encode()).hexdigest()[:16]

        with open(f"{base.conf.cachedir}/{repo.id}-{digest}/repodata/repomd.xml", "rb") as f:
            repomd = f.read()

        checksums[repo.id] = "sha256:" + hashlib.sha256(repomd).hexdigest()

    return checksums


call = json.load(sys.stdin)
command = call["command"]
arguments = call.get("arguments", {})

if command == "dump":
    base = create_base(arguments.get("repos", {}))
    packages = []
    for package in base.sack.query().available():
        packages.append({
            "name": package.name,
            "summary": package.summary,
            "description": package.description,
            "url": package.url,
            "epoch": package.epoch,
            "version": package.version,
            "release": package.release,
            "arch": package.arch,
            "buildtime": timestamp_to_rfc3339(package.buildtime),
            "license": package.license
        })
    json.dump({
        "checksums": repo_checksums(base),
        "packages": packages
    }, sys.stdout)

elif command == "depsolve":
    base = create_base(arguments.get("repos", {}))
    errors = []

    try:
        base.install_specs(arguments["package-specs"])
    except dnf.exceptions.MarkingErrors as e:
        exit_with_dnf_error("MarkingErrors", f"Error occurred when marking packages for installation: {e}")

    try:
        base.resolve()
    except dnf.exceptions.DepsolveError as e:
        exit_with_dnf_error("DepsolveError", f"There was a problem depsolving {arguments['package-specs']}: {e}")

    dependencies = []
    for package in base.transaction.install_set:
        dependencies.append({
            "name": package.name,
            "epoch": package.epoch,
            "version": package.version,
            "release": package.release,
            "arch": package.arch
        })
    json.dump({
        "checksums": repo_checksums(base),
        "dependencies": dependencies
    }, sys.stdout)