#!/usr/bin/env python3

from git import Repo
from git import Actor
import shutil
import os

WORKING_DIR = "/tmp/push-dotfiles"
GIT_REPO_URL = "git@git.seanomik.net:SeanOMik/nixos-dotfiles.git"

## Get a yes or no answer from the user and handle invalid input
def get_yes_no_answer(question: str, error_msg: str = "ERROR: Malformed input!"):
    ans = ""

    while ans != "y" or ans != "n":
        print(f"{question} (y,n): ", end="")
        ans = input()

        if ans != "y" or ans != "n":
            print(error_msg)
    
    if ans == "y":
        return True
    elif ans == "n":
        return False 

## Clears the working directory
def remove_working_dir():
    if os.path.exists(WORKING_DIR):
        shutil.rmtree(WORKING_DIR)
        print(f"Removed working directory ({WORKING_DIR}).")
    else:
        print(f"Skipping deletion of working directory since it doesn't exist.")

## Copy the dotfiles (/etc/nixos) to the working directory
def copy_dotfiles():
    src_directory = "/etc/nixos"
    for filename in os.listdir(src_directory):
        if filename == ".git":
            continue
        else:
            full_path = os.path.join(src_directory, filename)
            if os.path.isdir(full_path):
                shutil.copytree(full_path, os.path.join(WORKING_DIR, filename))
            else:
                shutil.copy(full_path, WORKING_DIR)

    print("Copied \"/etc/nixos\" dotfiles to working directory.")

## Clone the git repository to the working dir
def clone_git_repo():
    print("Cloning git repository...")
    Repo.clone_from(GIT_REPO_URL, WORKING_DIR)
    print("Cloned git repository!")

## Clear the working directory
def clear_working_dir():
    for filename in os.listdir(WORKING_DIR):
        if filename == ".git" or filename.endswith(".py") or filename == "shell.nix":
            continue
        else:
            full_path = os.path.join(WORKING_DIR, filename)
            if os.path.isdir(full_path):
                shutil.rmtree(full_path)
            else:
                os.remove(full_path)
    print("Cleared git repo...")

## Get the git repository in the working dir
def get_git_repo():
    return Repo(WORKING_DIR)

## Stage changes
def stage_git_changes(repo: Repo):
    file_diff_list = []

    # TODO: Check for the staged changes also
    diff = repo.index.diff(None)

    if len(diff) == 0:
        diff = repo.index.diff("HEAD")

        if len(diff) == 0:
            print("ERROR: No changes have been made!")
            exit()
        else:
            print("All changes are already staged...")
            return

    print("Git diff:")
    for item in diff:
        if item.deleted_file:
            print(f"  D - {item.a_path}")

            file_diff_list.append(os.path.join(repo.working_tree_dir, item.a_path))
        elif item.new_file:
            print(f"  N - {item.b_path}")

            file_diff_list.append(os.path.join(repo.working_tree_dir, item.b_path))
        elif item.renamed_file:
            print(f"  R - {item.a_path} to {item.b_path}")
            
            file_diff_list.append(os.path.join(repo.working_tree_dir, item.b_path))
        else:
            print(f"  C - {item.a_path}")
            
            file_diff_list.append(os.path.join(repo.working_tree_dir, item.a_path))

    ans = get_yes_no_answer("Stage entire diff?")

    if ans:
        for diff in file_diff_list:
            repo.git.add(diff)

        print("Staged all changes")
    else:
        print("TODO: Create numbered list to only stage certain files") # TODO

## Get the author from the user
def get_git_author(repo: Repo):
    ans = get_yes_no_answer("Use git config user?")
    if ans:
        username = repo.config_reader().get_value("user", "name")
        email = repo.config_reader().get_value("user", "email")

        print(f"Got git author:\n  Username: {username}\n  Email: {email}")
        
        ans = get_yes_no_answer("Is this author correct?")

        if ans:
            return Actor(username, email)
        else:
            return get_git_author(repo)
    else:
        print("Enter username: ", end="")
        username = input()

        print("Enter email: ", end="")
        email = input()

        return Actor(username, email)

## Commit changes
def commit_changes(repo: Repo, message: str, author: Actor):
    res = repo.git.commit('-S', '-m', f'"{message}"',  author=f'"{author.name} <{author.email}>"')
    print(res)
    print("Committed changes!")

## Push git changes to the repo!
def push_git_changes():
    repo = get_git_repo()
    stage_git_changes(repo)

    ans = ""

    while len(ans) == 0:
        print("Commit message: ", end="")
        ans = input()

        if len(ans) == 0:
            print("ERROR: Cannot use an empty commit message!")

    commit_changes(repo, ans, get_git_author(repo))

    # Actually push now
    print("Pushing changes...")
    origin = repo.remote(name='origin')
    origin.push()
    print("Pushed changes!")

def main():
    remove_working_dir();

    clone_git_repo();
    clear_working_dir();

    copy_dotfiles();
    push_git_changes();

    print("Done!")
    
if __name__ == '__main__':
    main()