#!/usr/bin/env python3
"""Small, dependency-free Last.fm API client used by the lastfm skill."""
import argparse
import json
import os
import sys
import urllib.parse
import urllib.request

API = "https://ws.audioscrobbler.com/2.0/"
METHODS = {
    "user info": "user.getinfo", "user recent-tracks": "user.getrecenttracks",
    "user top-artists": "user.gettopartists", "user top-tracks": "user.gettoptracks",
    "user loved-tracks": "user.getlovedtracks", "user friends": "user.getfriends",
    "user weekly-charts": "user.getweeklychartlist", "artist similar": "artist.getsimilar",
    "artist info": "artist.getinfo", "artist top-tracks": "artist.gettoptracks",
    "artist search": "artist.search", "album info": "album.getinfo", "album search": "album.search",
    "track similar": "track.getsimilar", "track search": "track.search",
    "tag top-artists": "tag.gettopartists", "tag top-tracks": "tag.gettoptracks",
    "tag top-albums": "tag.gettopalbums", "chart top-artists": "chart.gettopartists",
    "geo top-artists": "geo.gettopartists", "geo top-tracks": "geo.gettoptracks",
}

def parser():
    p = argparse.ArgumentParser(description="Last.fm API client", epilog="Examples: lastfm-cli artist similar Radiohead --limit 5")
    p.add_argument("--json", action="store_true", help="emit JSON")
    p.add_argument("--dry-run", action="store_true", help="show the API plan without a request")
    subs = p.add_subparsers(dest="group", required=True)
    for group, commands in {"user": ["info", "recent-tracks", "top-artists", "top-tracks", "loved-tracks", "friends", "weekly-charts"], "artist": ["similar", "info", "top-tracks", "search"], "album": ["info", "search"], "track": ["similar", "search", "scrobble", "now-playing", "love"], "tag": ["top-artists", "top-tracks", "top-albums"], "chart": ["top-artists"], "geo": ["top-artists", "top-tracks"], "auth": ["get-token", "get-session"]}.items():
        gp = subs.add_parser(group)
        cs = gp.add_subparsers(dest="command", required=True)
        for command in commands:
            cp = cs.add_parser(command)
            if group in {"user", "artist", "album", "tag", "geo"} or group == "track":
                cp.add_argument("values", nargs="*", metavar="VALUE", help="username, artist, tag, country, or track values")
            cp.add_argument("--limit", type=int)
            cp.add_argument("--period")
            cp.add_argument("--autocorrect", action="store_true")
    return p

def main():
    args = parser().parse_args()
    key = f"{args.group} {args.command}"
    if args.group == "auth":
        print("Auth operations require LASTFM_API_KEY, LASTFM_API_SECRET, and a browser authorization flow.")
        return 0
    values = getattr(args, "values", [])
    if args.command not in {"search", "top-artists", "top-tracks", "top-albums", "weekly-charts"} and not values:
        parser().error(f"{args.group} {args.command}: a value is required")
    method = METHODS.get(key)
    if not method:
        parser().error(f"unsupported operation: {key}")
    params = {"method": method, "format": "json"}
    if values:
        param = "user" if args.group == "user" else "country" if args.group == "geo" else "tag" if args.group == "tag" else "artist"
        params[param] = values[0]
        if args.group in {"track", "album"} and len(values) > 1:
            params["track" if args.group == "track" else "album"] = values[1]
    for option in ("limit", "period", "autocorrect"):
        value = getattr(args, option, None)
        if value not in (None, False): params[option] = value
    if args.dry_run:
        print(json.dumps({"dry_run": True, "url": API, "params": params}, indent=2))
        return 0
    api_key = os.getenv("LASTFM_API_KEY")
    if not api_key:
        print("LASTFM_API_KEY is required", file=sys.stderr)
        return 2
    params["api_key"] = api_key
    try:
        with urllib.request.urlopen(f"{API}?{urllib.parse.urlencode(params)}", timeout=30) as response:
            payload = json.load(response)
    except Exception as exc:
        print(f"Last.fm request failed: {exc}", file=sys.stderr)
        return 1
    print(json.dumps(payload, indent=2) if args.json else json.dumps(payload, indent=2))
    return 0

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