"""Verify downloaded uncompressed files against the SHA256 inventory."""
import argparse
import hashlib
import json
from pathlib import Path, PurePosixPath

def sha(path):
    h=hashlib.sha256()
    with path.open('rb') as f:
        for b in iter(lambda:f.read(4*1024**2),b''):h.update(b)
    return h.hexdigest()

def verify(root,collection):
    manifest=json.loads((root/'metadata/manifest.json').read_text())
    inventory=root/manifest['file_inventory']['path']
    if inventory.stat().st_size!=manifest['file_inventory']['bytes'] or sha(inventory)!=manifest['file_inventory']['sha256']:
        raise ValueError('File inventory checksum mismatch')
    files=size=0
    prefix={'qlib':'qlib/','minutes':'A股分钟/','all':''}[collection]
    with inventory.open() as f:
        for line in f:
            row=json.loads(line);rel=PurePosixPath(row['path'])
            if rel.is_absolute() or '..' in rel.parts:raise ValueError('Unsafe inventory path')
            if not row['path'].startswith(prefix):continue
            path=root.joinpath(*rel.parts)
            if not path.is_file() or path.stat().st_size!=row['bytes'] or sha(path)!=row['sha256']:
                raise ValueError('File verification failed: '+row['path'])
            files+=1;size+=row['bytes']
            if files%10000==0:print(f'Verified {files:,} files / {size:,} bytes',flush=True)
    selected=[c for c in manifest['collections'] if c['path_in_repo'].startswith(prefix)]
    if files!=sum(c['files'] for c in selected) or size!=sum(c['bytes'] for c in selected):
        raise ValueError('Collection totals mismatch')
    return {'collection':collection,'files':files,'bytes':size,'sha256_verified':True}

def main():
    p=argparse.ArgumentParser(description=__doc__)
    p.add_argument('--repo',type=Path,default=Path('./stock_dataset'))
    p.add_argument('--collection',choices=['qlib','minutes','all'],default='all')
    args=p.parse_args();print(json.dumps(verify(args.repo,args.collection),indent=2))

if __name__=='__main__':main()