#!/usr/bin/python3
"""Check the archive for missing dependencies"""
import apt_pkg


def fmt_dep(dep):
    """Format a Dependency object [of apt_pkg] as a string."""
    ret = dep.target_pkg.name
    if dep.target_ver:
        ret += f" ({dep.comp_type} {dep.target_ver})"
    return ret


def check_version(pkgver):
    """Check the version of the package"""
    missing = []

    for or_group in pkgver.depends_list.get(
        "Pre-Depends", []
    ) + pkgver.depends_list.get("Depends", []):
        if not any(dep.all_targets() for dep in or_group):
            # If none of the or-choices can be satisfied, add it to missing
            missing.append(or_group)

    if missing:
        print("Package:", pkgver.parent_pkg.name)
        print("Version:", pkgver.ver_str)
        print("Missing:")
        print(
            ", ".join(" | ".join(fmt_dep(dep) for dep in or_group))
            for or_group in missing
        )
        print()


def main():
    """The main function."""
    apt_pkg.init_config()
    apt_pkg.init_system()

    cache = apt_pkg.Cache()

    for pkg in sorted(cache.packages, key=lambda pkg: pkg.name):
        # pkg is from a list of packages, sorted by name.
        for version in pkg.version_list:
            # Check every version
            for pfile, _ in version.file_list:
                if (
                    pfile.origin == "Debian"
                    and pfile.component == "main"
                    and pfile.archive == "unstable"
                ):
                    # We only want packages from Debian unstable main.
                    check_version(version)
                    break


if __name__ == "__main__":
    main()