"""Fetch library files the local meta folder never downloaded.

The AstralRinth install has the 1.12.2 java libraries but not the
natives-windows classifiers, and the client cannot open a window without
lwjgl.dll. Rather than write into another application's cache, missing files go
into our own mirror of the same layout, which stage_run.py searches first.

    python fetch_missing.py <dest-root> <meta-dir>
"""

import json
import os
import sys
import urllib.request


def wanted(manifest):
    """Every artifact and natives-windows path the manifest declares."""
    out = []
    for entry in manifest['libraries']:
        downloads = entry.get('downloads') or {}
        artifact = (downloads.get('artifact') or {}).get('path')
        if artifact:
            out.append(artifact)
        classifiers = downloads.get('classifiers') or {}
        for key, value in classifiers.items():
            if key.startswith('natives-windows') and value and value.get('path'):
                out.append(value['path'])
    return sorted(set(out))


def main():
    dest_root, meta = sys.argv[1], sys.argv[2]
    manifest_path = os.path.join(meta, 'versions', '1.12.2', '1.12.2.json')
    with open(manifest_path, encoding='utf-8') as handle:
        manifest = json.load(handle)

    meta_lib = os.path.join(meta, 'libraries')
    base = 'https://libraries.minecraft.net/'
    fetched, present, failed = [], 0, []

    for rel in wanted(manifest):
        if os.path.isfile(os.path.join(meta_lib, rel.replace('/', os.sep))):
            present += 1
            continue
        target = os.path.join(dest_root, rel.replace('/', os.sep))
        url = base + rel
        try:
            os.makedirs(os.path.dirname(target), exist_ok=True)
            with urllib.request.urlopen(url, timeout=60) as response:
                blob = response.read()
            with open(target, 'wb') as handle:
                handle.write(blob)
            fetched.append('%s (%d bytes)' % (os.path.basename(rel), len(blob)))
        except Exception as error:                      # noqa: BLE001
            failed.append('%s -> %s' % (rel, error))

    print('already present: %d' % present)
    print('fetched: %d' % len(fetched))
    for line in fetched:
        print('  %s' % line)
    if failed:
        print('failed: %d' % len(failed))
        for line in failed:
            print('  %s' % line)
    return 1 if failed else 0


if __name__ == '__main__':
    raise SystemExit(main())