#!/usr/bin/python3
"""check-snapshots greps the directory tree for rpmrepo urls and checks them
against the current snapshot list"""

import argparse
import json
import os
import subprocess
import sys
import time
from urllib.parse import urlparse

import requests

SNAPSHOTS_URL = "https://rpmrepo.osbuild.org/v2/enumerate"
SNAPSHOTS_TIMEOUT = 2 * 60
SNAPSHOT_GREP = ["grep", "--color=never", "-or", r"http.*rpmrepo.osbuild.org.*-20[0-9]\+"]


def fetch_snapshots_api(url, timeout=SNAPSHOTS_TIMEOUT):
    """Get the list of snapshots from the rpmrepo API"""
    print(f"Fetching list of snapshots from {url}")
    start = time.time()
    try:
        r = requests.get(url, timeout=timeout)
    except BaseException as e:  # pylint: disable=broad-exception-caught
        print(f"Problem downloading {url}: {e}")
        return None
    elapsed = time.time() - start
    if r.status_code != 200:
        print(f"HTTP Response {r.status_code} from {url} after {elapsed:0.0f}s: {r.text}")
        return None
    print(f"Received snapshot list in {elapsed:0.0f}s")
    return r.json()


def find_snapshot_urls(directory):
    """grep the directory for rpmrepo snapshot urls

    Returns a map of urls to the files they are used in.
    """
    urls = {}
    try:
        grep_out = subprocess.run(SNAPSHOT_GREP + [directory],
                                  check=True,
                                  capture_output=True,
                                  env={"LANG": "C"})
    except subprocess.CalledProcessError as e:
        print("ERROR: " + e.stderr.decode("utf-8"))
        sys.exit(1)

    for line in grep_out.stdout.decode("utf-8").splitlines():
        try:
            file, url = line.split(":", 1)
        except ValueError:
            print(f"Problem parsing {line}")
            continue
        url = url.strip()
        if url not in urls:
            urls[url] = [file]
        else:
            urls[url].append(file)

    return urls


def check_baseurl(repo, snapshots):
    """Check the baseurl to see if it is a valid snapshot, and if there is a newer one
    available.
    """
    invalid = None
    newer = None
    url = urlparse(repo)
    snapshot = os.path.basename(url.path)

    # Is this snapshot valid?
    if snapshot not in snapshots:
        invalid = f"{snapshot} is not a valid snapshot name"

    # is this snapshot old?
    base = snapshot.rsplit("-", 1)[0]
    newest = snapshot
    for s in snapshots:
        if s.rsplit("-", 1)[0] != base:
            continue
        if s > newest:
            newest = s
    if newest != snapshot:
        newer = f"{snapshot} has a newer version - {newest}"

    return invalid, newer


# pylint: disable=too-many-branches
def check_snapshot_urls(urls, snapshots, skip=("test/data/assemblers", "test/data/manifests", "test/data/stages"),
                        errors_only=False):
    """check the urls against the current list of snapshots

    Returns:
        0 if all were valid and no newer snapshots are available
        2 if there were invalid snapshots
        3 if there were newer snapshots
        6 if there were invalid and newer snapshots
    """
    # Gather up the messages for each file
    messages = {}
    ret = 0
    for url in urls:
        invalid, newer = check_baseurl(url, snapshots)
        if invalid:
            # Add this to each file's invalid message list
            for f in urls[url]:
                if any(bool(s in f) for s in skip):
                    continue
                ret |= 2
                if f in messages:
                    if invalid not in messages[f]["invalid"]:
                        messages[f]["invalid"].append(invalid)
                else:
                    messages[f] = {"invalid": [invalid], "newer": []}

        if errors_only:
            continue

        if newer:
            # Add this to each file's newer message list
            for f in urls[url]:
                if any(bool(s in f) for s in skip):
                    continue
                ret |= 4
                if f in messages:
                    if newer not in messages[f]["newer"]:
                        messages[f]["newer"].append(newer)
                else:
                    messages[f] = {"newer": [newer], "invalid": []}

    # Print the messages for each file
    for f, msgs in messages.items():
        print(f"{f}:")
        for msg in msgs["invalid"]:
            print(f"    ERROR: {msg}")
        for msg in msgs["newer"]:
            print(f"    NEWER: {msg}")

    return ret


# parse cmdline args
def parse_args():
    parser = argparse.ArgumentParser(description="Check snapshot urls")
    parser.add_argument("--verbose")
    parser.add_argument("--timeout", type=int, default=SNAPSHOTS_TIMEOUT,
                        help="How long to wait for rpmrepo snapshot list")
    parser.add_argument("--cache", help="Use a cached file for the list of rpmrepo snapshots")
    parser.add_argument("--url", default=SNAPSHOTS_URL,
                        help="URL to use for the list of rpmrepo snapshots")
    parser.add_argument("--errors-only", action="store_true",
                        help="Only return errors")
    parser.add_argument("directory")
    return parser.parse_args()


def main():
    args = parse_args()
    urls = find_snapshot_urls(args.directory)

    snapshots = None
    if args.cache:
        try:
            with open(args.cache, encoding="utf8") as f:
                snapshots = json.load(f)
        except FileNotFoundError:
            print(f"No snapshots cache found at {args.cache}")
            sys.exit(1)
    else:
        snapshots = fetch_snapshots_api(args.url, args.timeout)
        if not snapshots:
            print(f"Cannot download snapshots from {args.url}")
            sys.exit(1)

    return check_snapshot_urls(urls, snapshots, errors_only=args.errors_only)


if __name__ == '__main__':
    sys.exit(main())