import os
import click
import pkgutil
import ast
import shutil


def parse_imports(path):
    modules = []
    file = open(path)
    lines = file.readlines()
    for node in ast.iter_child_nodes(ast.parse(''.join(lines))):
        if isinstance(node, ast.ImportFrom) | isinstance(node, ast.Import):
            modules += [x.name for x in node.names] + [x.asname for x in node.names if x.asname is not None]
    file.close()
    return modules


@click.command()
@click.option(
    "-p", "--pckpath", type=str, required=True, default="saqc/funcs",
    help="Relative path to the package to be documented (relative to sphinx root)."
)
@click.option(
    "-t", "--targetpath", type=str, required=True, default="sphinx-doc/internal_doc_rst",
    help="Output folder path (relative to sphinx root). Will be overridden if already existent."
)
@click.option(
    "-sr", "--sphinxroot", type=str, required=True, default='..', help="Relative path to the sphinx root."
)
def main(pckpath, targetpath, sphinxroot):
    root_path = os.path.abspath(sphinxroot)
    targetpath = os.path.join(root_path, targetpath)
    pkg_path = os.path.join(root_path, pckpath)
    modules = []
    for _, modname, _ in pkgutil.walk_packages(path=[pkg_path], onerror=lambda x: None):
        modules.append(modname)

    emptyline = [""]

    # clear target directory:
    if os.path.isdir(targetpath):
        shutil.rmtree(targetpath)
    os.mkdir(targetpath)

    for module in modules:
        imports = parse_imports(os.path.join(pkg_path, f'{module}.py'))
        skiplist = [f'\t:skip: {k}' for k in imports]
        section = [module] + ["=" * len(module)]
        automodapi_directive = [".. automodapi:: " + pckpath.replace('/', '.') + '.' + module]
        no_heading = [f'\t:no-heading:']
        to_write = emptyline + section + emptyline + automodapi_directive + skiplist + no_heading
        to_write = "".join([f'{k}\r\n' for k in to_write])
        with open(os.path.join(targetpath, f'{module}.rst'), 'w+') as f:
            f.write(to_write)


if __name__ == "__main__":
    main()