"""Verify a daily-calendar fixture or an explicitly supplied URL using only the standard library."""
import argparse
import hashlib
import json
from pathlib import Path
from urllib.request import urlopen
from urllib.parse import urlsplit


def read_bytes(location):
    if location.startswith(("https://", "http://")):
        with urlopen(location, timeout=20) as response:
            return response.read()
    return Path(location).read_bytes()


def resource_name(location):
    if location.startswith(("https://", "http://")):
        return urlsplit(location).path.rsplit("/", 1)[-1]
    return Path(location).name


def verify(data_location, manifest_location):
    manifest = json.loads(read_bytes(manifest_location))
    data_bytes = read_bytes(data_location)
    name = resource_name(data_location)
    metadata = manifest.get("files", {}).get(name)
    if not metadata:
        raise ValueError("The manifest does not describe " + name)
    actual_hash = hashlib.sha256(data_bytes).hexdigest()
    if len(data_bytes) != metadata.get("bytes") or actual_hash != metadata.get("sha256"):
        raise ValueError("Daily-calendar file does not match its manifest hash and byte count")
    projection = json.loads(data_bytes)
    if projection.get("data_version") != manifest.get("data_version"):
        raise ValueError("Data version does not match the manifest")
    if projection.get("year") != manifest.get("year"):
        raise ValueError("Calendar year does not match the manifest")
    if len(projection.get("rows", [])) != manifest.get("rows_count"):
        raise ValueError("Row count does not match the manifest")
    return projection


def show_comparison(projection):
    by_date = {}
    unknown = 0
    for row in projection["rows"]:
        by_date.setdefault(row["date"], {})[row["market_id"]] = row
        if row["status"] == "unknown" and row["is_trading_day"] is None:
            unknown += 1
    differences = 0
    for date in sorted(by_date):
        pair = by_date[date]
        if "SSE" not in pair or "NB" not in pair:
            continue
        sse, nb = pair["SSE"], pair["NB"]
        if (sse["status"], sse["is_trading_day"]) != (nb["status"], nb["is_trading_day"]):
            print("{}: SSE={} NB={}".format(date, sse["status"], nb["status"]))
            differences += 1
    if differences == 0:
        print("No SSE/NB differences in this fixture.")
    print("SSE/NB different dates: {}".format(differences))
    print("Unknown rows retained: {}".format(unknown))
    print("Data version: {}".format(projection["data_version"]))


def main():
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--data", required=True, help="Local JSON file or explicit HTTP(S) URL")
    parser.add_argument("--manifest", required=True, help="Local manifest JSON or explicit HTTP(S) URL")
    args = parser.parse_args()
    try:
        projection = verify(args.data, args.manifest)
        show_comparison(projection)
    except (OSError, ValueError, KeyError, json.JSONDecodeError) as error:
        parser.error(str(error))


if __name__ == "__main__":
    main()