#!python3

"""
Compares the contents (disregarding files' sizes and timestamps) of Haiku packages (.hpkg).

Useful to see, at first glance, if our newly built package looks more or less like the older ones.

Usage:
    > compare_packages.py <package_name>
    > compare_packages.py <package1.hpkg> <package2.hpkg>

First one compares the given <package_name> from:

  /system/packages/package_name-*.hpkg

  with the one from:

  {0}/package_name-*.hpkg

The second one compares the two given <package1> <package2> files.

Examples:
    > compare_packages.py ncurses6
    > compare_packages.py /foo/bar/some_package.hpkg ~/Downloads/some_package.hpkg
"""

from pprint import pprint

import os
import re
import subprocess
import sys


def usage():
    print(__doc__.format(hp_packages_dir()))
    exit()


def call(what, check_rc=True, shell=True):
    """Returns the text output of calling the `what` in a subprocess.
    
    set check_rc=False if the subprocess may fail (and you can handle that).
    """
    if check_rc:
        return subprocess.check_output([what], shell=shell, text=True)
    return subprocess.run([what], stdout=subprocess.PIPE, shell=shell, text=True).stdout


def get_package_filenames(package_name):
    """Returns a 2 items tuple of the first .hpkg filename that matches `package_name`.

    The first item from `/system/packages/`, the second from haikuporter's $TREE_PATH.
    """
    system = call('ls -1 /system/packages/%s-*.hpkg' % package_name, check_rc=False)
    local = call('ls -1 %s/%s-*.hpkg' % (hp_packages_dir(), package_name), check_rc=False)

    if system != '':
        system = system.splitlines()[0]
    if local != '':
        local = local.splitlines()[0]

    return system, local


def hp_packages_dir():
    result = call('source ~/config/settings/haikuports.conf && echo $PACKAGES_PATH').splitlines()[0]
    if result != "":
        return result

    result = call('source ~/config/settings/haikuports.conf && echo $TREE_PATH').splitlines()[0]
    if result != "":
        return result + '/packages'

    raise Exception("Failed to detect HaikuPorts' packages dir location. Is your 'haikuports.conf' properly setup?")


def diff(old, new):
    result = call('diff --color=always -u %s %s' % (old, new), check_rc=False)
    return result


def get_package_info(filename):
    pkg_info = call('package list -i %s' % filename).splitlines()
    pkg_files = call('package list -p %s' % filename).splitlines()

    return '\n'.join(pkg_info) + '\n'.join(sorted(pkg_files))


def main(package_name=None, package1=None, package2=None):
    if (package_name is not None) and (package1 is None and package2 is None):
        package1, package2 = get_package_filenames(package_name)
        errStr1 = 'Cannot locate a package named "%s" under /system/packages/' % package_name
        errStr2 = 'Cannot locate a package named "%s" under "%s"' % (package_name, hp_packages_dir())
    else:
        errStr1 = 'File "%s" doesn\'t exist/' % package1
        errStr2 = 'File "%s" doesn\'t exist/' % package2

    if not os.path.exists(package1):
        print(errStr1)
        exit()
    elif not os.path.exists(package2):
        print(errStr2)
        exit()

    print('\nComparing package files:\n\t%s\n\t%s\n' % (package1, package2))

    tmp_dir = '/boot/system/var/shared_memory'
    hpkginfo1 = tmp_dir + '/hpkginfo1.txt'
    hpkginfo2 = tmp_dir + '/hpkginfo2.txt'

    with open(hpkginfo1, 'w') as of:
        of.writelines(get_package_info(package1))

    with open(hpkginfo2, 'w') as nf:
        nf.writelines(get_package_info(package2))

    print(diff(hpkginfo1, hpkginfo2))

    os.unlink(hpkginfo1)
    os.unlink(hpkginfo2)


if __name__ == '__main__':
    if len(sys.argv) == 2:
        main(package_name=sys.argv[1])
    elif len(sys.argv) == 3:
        main(package1=sys.argv[1], package2=sys.argv[2])
    else:
        usage()