#!/bin/env python3

"""Interactively install fischerlings dotfiles"""

import argparse
import os
import pwd
import sys
import subprocess

user = pwd.getpwuid(os.getuid())[0]
home_dir = os.getenv("HOME")
cwd = os.getcwd()

def fish_config(quiet):
    """install and run fisherman"""
    # download fisherman
    import urllib.request

    if not quiet:
        print("Installing fisherman, see: https://github.com/fisherman/fisherman")
    with urllib.request.urlopen("https://git.io/fisherman") as f:
        fisher = f.read().decode("utf-8")

    dir_path = home_dir+"/.config/fish/functions/"
    # install fisherman at $fish_config/functions/
    if not os.path.exists(dir_path):
        os.mkdir(dir_path)
    else:
        if not os.path.exists(dir_path+"fisher.fish"):
            file = open(dir_path+"fisher.fish", 'w')
            file.write(fisher)
        else:
            if not quiet:
                print("fisherman already installed")
                return

    if not quiet:
        print("Installed fisherman -> execute fisher to pull plugins")

    subprocess.run(["fish", dir_path+"fisher.fish"])

def dotfile_loc_helper(quiet):
    """Create a symlink of get_dotfiles_location.sh into the path"""

    if not os.path.exists(home_dir+"/.local/bin"):
        os.mkdir(home_dir+"/.local/bin")

    try:
        os.symlink(cwd + "/get_dotfiles_location.sh",
                home_dir + "/.local/bin/get_dotfiles_location")
    except Exception as e:
        if isinstance(e, FileExistsError):
            pass
        else:
            return e

def offlineimap_passwd(quiet):
    """Write the environment file for the systemd unit"""
    res = dotfile_loc_helper(quiet)
    if res:
        return res
    env_file_path = "/etc/systemd/system/offlineimap@fischerling.env"
    if not os.path.exists(env_file_path):
        try:
            subprocess.run(["get_dotfiles_location", ">",
                env_file_path])
        except Exception as e:
            if isinstance(e, PermissionError):
                subprocess.run(["get_dotfiles_location", "|", "sudo", "tee", "-a",
                    env_file_path, ">", "/dev/null"])
            else:
                return e

def offlineimap_warn(quiet):
    """Print a warning about my offlineimap setup"""

    if not quiet:
        print("! WARNING !")
        print("My offlineimap setup uses a patched version !")
        print("The patch can be found at offlineimap/expandvars.patch.")
        print("Only proceed if you know what you are doing")
        if input("Want to continue ? (y/N) ") not in ["Y","y"]:
            exit("Aborting.")

# targets are a list of tuples<file name, link destination> and/or functions

targets = {
        "lumail":
            [("config/lumail2/lumail2.lua", home_dir + "/.config/lumail2/lumail2.lua")],
        "guixsd":
            [("guix/system.scm", "/etc/guix/system.scm"),
            ("guix/bashrc", home_dir + "/.bashrc")],
        "vimrc":
            [("vimrc", home_dir + "/.vimrc")],
        "vim.d":
            [("vim", home_dir + "/.vim")],
        "vis":
            [("config/vis", home_dir + "/.config/vis")],
        "ssh-config":
            [("ssh/config", home_dir + "/.ssh/config")],
        "X":
            [("xinitrc", home_dir + "/.xinitrc"),
            ("xinitrc", home_dir + "/.xsession"),
            ("xprofile", home_dir + "/.xprofile"),
            dotfile_loc_helper,
            ("Xresources", home_dir + "/.Xresources")],
        "mutt":
            [("muttrc", home_dir + "/.muttrc"),
            ("mutt", home_dir + "/.mutt"),
            ("scripts/mutt.sh", home_dir+"/.local/bin/mutt.sh")],
        "zshrc":
            [("zshrc", home_dir + "/zshrc")],
        "i3-config":
            [("i3", home_dir + "/.i3"),
            dotfile_loc_helper],
        "dir_colors":
            [("dir_colors", home_dir + "/.dir_colors")],
        "fish-config":
            [("config/fish/config.fish", home_dir + "/.config/fish/config.fish"),
            ("config/fish/fishfile", home_dir + "/.config/fish/fishfile"),
            dotfile_loc_helper,
            fish_config],
        "terminator-config":
            [("config/terminator/config", home_dir +
                                          "/.config/terminator/config")],
        "offlineimap":
            [offlineimap_warn,
            ("offlineimap/offlineimaprc", home_dir + "/.offlineimaprc"),
            ("offlineimap/offlineimap@.service",
                "/etc/systemd/system/offlineimap@" + user + ".service"),
            offlineimap_passwd],
        "msmtp":
            [("msmtprc", home_dir + "/.msmtprc")],
        "FAU":
            [("FAU/wl-FAU-STUD.gpg", "/etc/netctl/wl-FAU-STUD"),
            ("FAU/fau_stud.conf.gpg", ""),
            ("FAU/start_fau_wlan.sh", home_dir + "/.local/bin/start_fau_wlan")]
        }

git_submodules_for = ["vim.d", "vis"]

def install_target(target, quiet):
    """Install a target"""

    if not quiet:
        print("Installing", target, "...")

    for instruction in targets[target]:
        if isinstance(instruction, tuple):
            if not os.path.exists(instruction[0]):
                print("Can't find", instruction[0],
                        ". Please make sure you are in the right directory.",
                        file=sys.stderr)
            else:
                # check if file is encrypted
                if instruction[0][-4:] == ".gpg":
                    start_filename = instruction[0].rfind("/") + 1
                    if subprocess.run([
                            "gpg",
                            "--output",
                            "decrypted/" + instruction[0][start_filename:-4],
                            "-d",
                            instruction[0]]):
                        # adjust instruction[0]
                        instruction = (
                                "decrypted/" + instruction[0][start_filename:-4],
                                instruction[1])

                        # set privacy friendly file permissions 
                        if not subprocess.run(["chmod", "600", instruction[0]]):
                            print("Skipping because changing permissions of",
                                    instruction[1], "failed. This could be a",
                                    "privacy risk!", file=sys.stderr)
                            continue
                    else:
                        print("Decrypting failed", file=sys.stderr)
                        continue

                    # only continue linking/installing if instruction[1] is not ""
                    if instruction[1] == "":
                        continue

                if not quiet:
                    print("Installing", instruction[0], "to", instruction[1])
                try:
                    os.symlink(cwd + "/" + instruction[0], instruction[1])
                except Exception as e:
                    if isinstance(e, PermissionError):
                        subprocess.run(["sudo", "ln", "-s",
                                cwd + '/' + instruction[0], instruction[1]])
                    elif isinstance(e, FileExistsError):
                        print("File already exists", file=sys.stderr)
                    else:
                        print(e, file=sys.stderr)

        elif callable(instruction):
            if not quiet:
                print("Running function", instruction)
            res = instruction(quiet)
            if res:
                print("The instruction", instruction, "of", target,
                        "failed with", str(res) + ".", file=sys.stderr)
                print("This can leaf your installation in a broken state",
                        file=sys.stderr)
        else:
            print("I don't understand", instruction,
                    "\nThe instruction musst be a tuple or a function.",
                    "\nSKIPPING IT", file=sys.stderr)

    if target in git_submodules_for:
        choice = input(target + " uses git submodules want to pull them ? (Y/n) ")
        if choice in ["Y", "y", ""]:
            subprocess.run(["git", "submodule", "update", "--init"])


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument("-q", "--quiet", action="store_true")
    parser.add_argument("targets", type=str, nargs='*')

    args = parser.parse_args()

    if args.targets:
        for t in args.targets:
            install_target(t, args.quiet)
    else:
        if not args.quiet:
            print("Welcome to the installation script of fischerlings dotfiles.")
            print("Located at: https://github.com/fischerling/dotfiles")
            print()

        targets_ord = [x for x in targets]
        for i, target in zip(range(len(targets_ord)), targets_ord):
            print(str(i)+":", target)
        print("Enter n° of configurations to be installed or all")
        choice = input("==> ")
        
        if choice == "":
            pass
        elif "all" in choice:
            for target in targets:
                install_target(target, args.quiet)
        else:
            for n in choice.strip().split(" "):
                install_target(targets_ord[int(n)], args.quiet)

        if not args.quiet:
            print("Good Bye. Have fun with your new configuration")


if __name__ == "__main__":
    main()