"""Install or remove the patch in a Facade install. Needs only Python.

    python tools/install_patch.py [facade-install-folder]              # install
    python tools/install_patch.py [facade-install-folder] --uninstall  # put the originals back
    python tools/install_patch.py [facade-install-folder] --status

install.bat in the repo root runs this with administrator rights, which
writing into Program Files needs.

Only the class files listed in patch_manifest.py are touched. Every replaced
original is kept next to the new file as <name>.orig, and --uninstall restores
them and removes what was added. Safe to re-run. Restart the game afterwards; a
running game keeps the classes it already loaded.
"""
import shutil
import sys

from facade_install import PREBUILT_CLASSES, from_args
from original_parser import renamed_original_parser
from patch_manifest import ADDED, GENERATED, PREBUILT, REPLACED


def backup_of(path):
    return path.with_name(path.name + ".orig")


def status(classes):
    backed_up = [name for name in REPLACED if backup_of(classes / name).is_file()]
    if not backed_up:
        return "not installed"
    if len(backed_up) == len(REPLACED) and all((classes / name).is_file() for name in ADDED + GENERATED):
        return "installed"
    return "partly installed (an older version of the patch?): run install again"


def install(classes):
    missing = [name for name in PREBUILT if not (PREBUILT_CLASSES / name).is_file()]
    if missing:
        sys.exit("patch/prebuilt is missing %s; is the checkout complete?" % ", ".join(missing))
    # Made from the player's own copy of the game, before anything is replaced.
    original_parser = renamed_original_parser(classes)
    for name in REPLACED:
        if not backup_of(classes / name).exists():
            shutil.copy2(classes / name, backup_of(classes / name))
    (classes / GENERATED[0]).write_bytes(original_parser)
    for name in PREBUILT:
        shutil.copy2(PREBUILT_CLASSES / name, classes / name)
    print("installed into %s" % classes)
    print("originals kept as *.orig; restart the game to load the new classes")


def uninstall(classes):
    restored = 0
    for name in REPLACED:
        backup = backup_of(classes / name)
        if backup.is_file():
            shutil.copy2(backup, classes / name)
            backup.unlink()
            restored += 1
    if restored == 0:
        sys.exit("not installed (no .orig backups)")
    for name in ADDED + GENERATED:
        (classes / name).unlink(missing_ok=True)
    print("restored %d original classes in %s" % (restored, classes))


def main():
    classes = from_args(sys.argv).classes
    try:
        if "--status" in sys.argv:
            print(status(classes))
        elif "--uninstall" in sys.argv:
            uninstall(classes)
        else:
            install(classes)
    except PermissionError:
        sys.exit("Windows will not let this process write to %s.\n"
                 "Use install.bat, or a terminal opened with 'Run as administrator'." % classes)


if __name__ == "__main__":
    main()