import ast
import os
import subprocess
import config

def get_assignments(filename):
    with open(filename) as f:
        tree = ast.parse(f.read(), filename)

    assignments = {node.targets[0].id: ast.literal_eval(node.value) for node in ast.walk(tree) if isinstance(node, ast.Assign)}
    return assignments


def update_config(current_config, example_config):
    current_assignments = get_assignments(current_config)
    example_assignments = get_assignments(example_config)

    missing_assignments = {var: value for var, value in example_assignments.items() if var not in current_assignments}

    if missing_assignments:
        with open(current_config, 'ab+') as f:  # Open the file in binary mode
            f.seek(-1, os.SEEK_END)  # Move the cursor to the last character
            last_char = f.read(1)  # Read the last character

        # If the last character is not a newline, write a newline
        if last_char != b'\n':
            with open(current_config, 'a') as f:  # Open the file in text mode
                f.write('\n')

        # Write the missing assignments
        with open(current_config, 'a') as f:
            for var, value in missing_assignments.items():
                f.write('{} = {!r}\n'.format(var, value))


def display_config_differences(current_config, example_config, display=True):
    current_assignments = get_assignments(current_config)
    example_assignments = get_assignments(example_config)

    missing_assignments = {var: value for var, value in example_assignments.items() if var not in current_assignments}

    if missing_assignments:
        if display: 
            print("Missing variables:")
            for var, value in missing_assignments.items():
                print('\n{} = {!r}'.format(var, value))
        return True
    else:
        return False

def check_git_version_remote(script_dir):
    full_cmd = "git -C {} ls-remote --tags origin | awk -F'/' '{{print $3}}' | sort -V | tail -n 1".format(script_dir)
    result = subprocess.Popen(full_cmd, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE).communicate()[0].decode("utf-8")
    latest_tag = result.strip()
    return latest_tag if latest_tag else None


def update_config_version(version, script_dir):
    with open(script_dir + '/config.py', 'r') as f:
        lines = f.readlines()

    with open(script_dir + '/config.py', 'w') as f:
        print(":: Updating config version to {}".format(version))
        for line in lines:
            if 'version = ' in line:
                f.write('version = "{}"\n'.format(version))
            else:
                f.write(line)


def do_update(script_dir, version=config.version, git_update=True, config_update=True):
    print("Current version: {}".format(config.version))
    if git_update:
        print(":: Updating git repository", script_dir)
        result = subprocess.run(['git', '-C', script_dir, 'pull'], check=True, universal_newlines=True, stdout=subprocess.PIPE)
        print(result.stdout)

    if display_config_differences(script_dir + '/config.py', script_dir + '/config.py.example') and config_update:
        print(":: Updating config.py")
        update_config(script_dir + '/config.py',script_dir + '/config.py.example')

    if version != config.version:
        update_config_version(version, script_dir)


if __name__ == '__main__':
    script_dir = os.path.dirname(os.path.realpath(__file__))
    do_update(script_dir,check_git_version_remote(script_dir))