#!/usr/bin/env -S uv run
"""
Download UD metadata for the different releases from the lindat clarin-dspace
repository into `./etc/`:
- BibTeX "Howto Cite"
  (use the item's own data from the webpage)
- dc.description
  (use the clarin-dspace API to retrieve the item's metadata)

We assume a clarin-dspace infrastructure with:
- ".../repository/server/api/core/refbox/citations?type=bibtex&handle="
  returning a bibtex entry for the given hdl
- ".../repository/server/api/core/items/" as the API endpoint (core/items)
"""

import json
import re
import argparse
import logging
from pathlib import Path
from urllib.error import URLError
from urllib.request import urlopen
from urllib.parse import urlparse

# URL prefix
citation_url_prefix = "https://lindat.mff.cuni.cz/repository/server/api/core/refbox/citations?type=bibtex&handle="
description_url_prefix = "https://lindat.mff.cuni.cz/repository/server/api/core/items/"
handle_url_prefix = "http://hdl.handle.net/"
handle_redirect_url_prefix = "https://lindat.mff.cuni.cz/repository/items/"

TOOLS_DIR = Path(__file__).resolve().parent
OUTPUT_DIR = TOOLS_DIR / "etc"
citation_outfile_name = "citation-{rev}"
description_outfile_name = "description-{rev}"
release_handle_map_file = OUTPUT_DIR / "ud_release_handles.tsv"

def load_release_handles(path: Path) -> dict[str, str]:
    """
    Load the UD-version -> LINDAT handle mapping from a TSV file.
    """
    mapping: dict[str, str] = {}
    with path.open("r", encoding="utf-8") as fh:
        for lineno, raw_line in enumerate(fh, start=1):
            line = raw_line.strip()
            if not line or line.startswith("#"):
                continue
            fields = line.split()
            if len(fields) != 2:
                raise ValueError(f"Invalid mapping format at {path}:{lineno}: {raw_line.rstrip()}")
            rev, handle = fields
            mapping[rev] = handle
    return mapping

# Parse command line arguments
parser = argparse.ArgumentParser(description=__doc__,
                                 formatter_class=argparse.RawDescriptionHelpFormatter)
parser.add_argument('-o', '--override', action='store_true',
                    help='override output file if it already exists')
parser.add_argument('--ud-ver', dest='ud_ver',
                    help='only fetch one UD version (e.g. 2.17)')
# Backward-compatible alias (hidden from --help)
parser.add_argument('-r', '--rev', dest='ud_ver', help=argparse.SUPPRESS)
parser.add_argument('-v', '--verbose', action='count', default=0,
                    help='increase verbosity level')
args = parser.parse_args()

# Set up logging
logging.basicConfig(
    level = max(logging.DEBUG, logging.INFO - args.verbose * 10),
    format='%(asctime)s [%(levelname)s] %(message)s',
    datefmt='%Y-%m-%d %H:%M:%S'
)

# Load version -> handle mapping
try:
    url_postfixes = load_release_handles(release_handle_map_file)
except (OSError, ValueError) as e:
    raise SystemExit(f"Failed to load release-handle mapping from {release_handle_map_file}: {e}")

if args.ud_ver:
    if args.ud_ver not in url_postfixes:
        known = ", ".join(sorted(url_postfixes.keys()))
        raise SystemExit(f"Unknown UD version '{args.ud_ver}'. Known versions: {known}")
    url_postfixes = {args.ud_ver: url_postfixes[args.ud_ver]}

OUTPUT_DIR.mkdir(parents=True, exist_ok=True)

# Iterate over the URL postfixes
for rev,handle in url_postfixes.items():

    try:
        # Construct the full URL
        citation_url = citation_url_prefix + handle
        logging.debug(f"Using Citation URL: {citation_url}")

        # Send a GET request to the URL
        with urlopen(citation_url) as response:

            # Read the JSON content
            data = json.loads(response.read().decode())

            # Extract the metadata field
            metadata = data.get("metadata")

            # Write the metadata to the output file
            if metadata:
                # Replace uneven space(s) at the beginning of lines with fixed
                # number of spaces
                metadata = "\n".join([re.sub('^( )+', '   ', line) for line in
                            metadata.split("\n")])

                # Open the output file in write mode
                output_fn = OUTPUT_DIR / citation_outfile_name.format(rev=rev)
                if args.override or not output_fn.exists():
                    with output_fn.open("w") as fh:
                        fh.write(metadata + "\n")
                        logging.info(f"Successfully downloaded citation from {citation_url} and written to {output_fn}.")
                else:
                    logging.info(f"Output {output_fn} already exists: Not overriding.")


        # Construct the full URL
        handle_url = handle_url_prefix + handle
        logging.debug(f"Using handle URL: {handle_url}")
        # Send a GET request to the URL
        with urlopen(handle_url) as response:
            if response.url.startswith(handle_redirect_url_prefix):
                itemid = (urlparse(response.url)).path.rsplit("/", 1)[-1]

                description_url = description_url_prefix + itemid
                with urlopen(description_url) as response:
                    data = json.loads(response.read().decode())
                    description = data["metadata"]["dc.description"][0]["value"]
                    if description:

                        # Open the output file in write mode
                        output_fn = OUTPUT_DIR / description_outfile_name.format(rev=rev)
                        if args.override or not output_fn.exists():
                            with output_fn.open("w") as fh:
                                fh.write(description+ "\n")
                                logging.info(f"Successfully downloaded description from {description_url} and written to {output_fn}.")
                        else:
                            logging.info(f"Output {output_fn} already exists: Not overriding.")

    except URLError as e:
        logging.error(f"Error downloading: {e}")
    except json.JSONDecodeError as e:
        logging.error(f"Error decoding JSON: {e}")