#!/usr/bin/python3

import codecs
import subprocess
import os
import sys

PACORPHAN_PATH = os.path.expanduser("~/.pacorphan")

def run(cmd):
    for line in subprocess.check_output(cmd).decode("utf-8").split("\n"):
        line = line.strip()
        if line:
            yield line

def strip_comment(line):
    pos = line.find("#")
    if pos >= 0:
        line = line[:pos]
    return line.strip()


keep_pkg_list = []
mark_explicit_list = []
need_install_list = []
unneeded_pkg_list = []
installed_pkg_list = []
explicit_pkg_list = []

for filename in os.listdir(PACORPHAN_PATH):
    if filename.startswith("."):
        continue
    filename = os.path.join(PACORPHAN_PATH, filename)
    for pkg in codecs.open(filename, "r", "utf-8"):
        pkg = strip_comment(pkg)
        if pkg in keep_pkg_list:
            print("# Duplicate entry: " + pkg)
        if pkg:
            keep_pkg_list.append(pkg.strip())

for pkg in run(["pacman", "-Qq"]):
    installed_pkg_list.append(pkg)

for pkg in run(["pacman", "-Qtq"]):
    unneeded_pkg_list.append(pkg)

for pkg in run(["pacman", "-Qeq"]):
    explicit_pkg_list.append(pkg)


for pkg in keep_pkg_list:
    if pkg in unneeded_pkg_list:
        unneeded_pkg_list.remove(pkg)

    if pkg in explicit_pkg_list:
        explicit_pkg_list.remove(pkg)
    else:
        if pkg in installed_pkg_list:
            mark_explicit_list.append(pkg)
        else:
            need_install_list.append(pkg)


if unneeded_pkg_list:
    print("# Found packages to remove")
    print("sudo pacman -R " + " ".join(unneeded_pkg_list))
    print()

if explicit_pkg_list:
    print("# Found explicitly installed packages to keep")
    print("echo " + " ".join(explicit_pkg_list) + " | tr ' ' '\\n' >> ~/.pacorphan/keep")
    print()

if mark_explicit_list:
    print("# Found packages which should be marked as explicitly installed")
    print("sudo pacman -D --asexplicit " + " ".join(mark_explicit_list))
    print()

if need_install_list:
    print("# Found packages which should be installed")
    print("sudo pacman -S " + " ".join(need_install_list))
    print()