"""Build script for Sphinx documentation"""

import argparse
from pathlib import Path

from sphinx.application import Sphinx


def create_parser():
    parser = argparse.ArgumentParser(description="Build PEP documents")
    # alternative builders:
    parser.add_argument("-l", "--check-links", action="store_true")
    parser.add_argument("-f", "--build-files", action="store_true")
    parser.add_argument("-d", "--build-dirs", action="store_true")

    # flags / options
    parser.add_argument("-w", "--fail-on-warning", action="store_true")
    parser.add_argument("-n", "--nitpicky", action="store_true")
    parser.add_argument("-j", "--jobs", type=int, default=1)

    # extra build steps
    parser.add_argument("-i", "--index-file", action="store_true")  # for PEP 0

    return parser.parse_args()


def create_index_file(html_root: Path, builder: str) -> None:
    """Copies PEP 0 to the root index.html so that /peps/ works."""
    pep_zero_file = "pep-0000.html" if builder == "html" else "pep-0000/index.html"
    try:
        pep_zero_text = html_root.joinpath(pep_zero_file).read_text(encoding="utf-8")
    except FileNotFoundError:
        return None
    if builder == "dirhtml":
        pep_zero_text = pep_zero_text.replace('="../', '="')  # remove relative directory links
    html_root.joinpath("index.html").write_text(pep_zero_text, encoding="utf-8")


if __name__ == "__main__":
    args = create_parser()

    root_directory = Path(".").absolute()
    source_directory = root_directory
    build_directory = root_directory / "build"  # synchronise with deploy-gh-pages.yaml -> deploy step
    doctree_directory = build_directory / ".doctrees"

    # builder configuration
    if args.build_files:
        sphinx_builder = "html"
    elif args.build_dirs:
        sphinx_builder = "dirhtml"
    elif args.check_links:
        sphinx_builder = "linkcheck"
    else:
        # default builder
        sphinx_builder = "dirhtml"

    # other configuration
    config_overrides = {}
    if args.nitpicky:
        config_overrides["nitpicky"] = True

    app = Sphinx(
        source_directory,
        confdir=source_directory,
        outdir=build_directory,
        doctreedir=doctree_directory,
        buildername=sphinx_builder,
        confoverrides=config_overrides,
        warningiserror=args.fail_on_warning,
        parallel=args.jobs,
    )
    app.builder.copysource = False  # Prevent unneeded source copying - we link direct to GitHub
    app.builder.search = False  # Disable search
    app.build()
    
    if args.index_file:
        create_index_file(build_directory, sphinx_builder)