# This file is part of beets.
# Copyright 2016, Dang Mai <contact@dangmai.net>.
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.

"""Generates smart playlists based on beets queries."""

from __future__ import annotations

import os
from typing import Any, TypeAlias
from urllib.parse import quote
from urllib.request import pathname2url

from beets import ui
from beets.dbcore.query import ParsingError, Query, Sort
from beets.library import Album, Item, Library, parse_query_string
from beets.plugins import BeetsPlugin
from beets.plugins import send as send_event
from beets.util import (
    bytestring_path,
    displayable_path,
    mkdirall,
    normpath,
    path_as_posix,
    sanitize_path,
    syspath,
)

QueryAndSort = tuple[Query, Sort]
PlaylistQuery = Query | tuple[QueryAndSort, ...] | None
PlaylistMatch: TypeAlias = tuple[
    str,
    tuple[PlaylistQuery, Sort | None],
    tuple[PlaylistQuery, Sort | None],
]


class SmartPlaylistPlugin(BeetsPlugin):
    def __init__(self) -> None:
        super().__init__()
        self.config.add(
            {
                "relative_to": None,
                "playlist_dir": ".",
                "auto": True,
                "playlists": [],
                "uri_format": None,
                "fields": [],
                "forward_slash": False,
                "prefix": "",
                "urlencode": False,
                "pretend_paths": False,
                "output": "m3u",
            }
        )

        self.config["prefix"].redact = True  # May contain username/password.
        self._matched_playlists: set[PlaylistMatch] = set()
        self._unmatched_playlists: set[PlaylistMatch] = set()

        if self.config["auto"]:
            self.register_listener("database_change", self.db_change)

    def commands(self) -> list[ui.Subcommand]:
        spl_update = ui.Subcommand(
            "splupdate",
            help="update the smart playlists. Playlist names may be "
            "passed as arguments.",
        )
        spl_update.parser.add_option(
            "-p",
            "--pretend",
            action="store_true",
            help="display query results but don't write playlist files.",
        )
        spl_update.parser.add_option(
            "--pretend-paths",
            action="store_true",
            dest="pretend_paths",
            help="in pretend mode, log the playlist item URIs/paths.",
        )
        spl_update.parser.add_option(
            "-d",
            "--playlist-dir",
            dest="playlist_dir",
            metavar="PATH",
            type="string",
            help="directory to write the generated playlist files to.",
        )
        spl_update.parser.add_option(
            "--relative-to",
            dest="relative_to",
            metavar="PATH",
            type="string",
            help="generate playlist item paths relative to this path.",
        )
        spl_update.parser.add_option(
            "--prefix",
            type="string",
            help="prepend string to every path in the playlist file.",
        )
        spl_update.parser.add_option(
            "--forward-slash",
            action="store_true",
            dest="forward_slash",
            help="force forward slash in paths within playlists.",
        )
        spl_update.parser.add_option(
            "--urlencode",
            action="store_true",
            help="URL-encode all paths.",
        )
        spl_update.parser.add_option(
            "--uri-format",
            dest="uri_format",
            type="string",
            help="playlist item URI template, e.g. http://beets:8337/item/$id/file.",
        )
        spl_update.parser.add_option(
            "--output",
            type="string",
            help="specify the playlist format: m3u|extm3u.",
        )
        spl_update.func = self.update_cmd
        return [spl_update]

    def update_cmd(self, lib: Library, opts: Any, args: list[str]) -> None:
        self.build_queries()
        if args:
            args_set = set(args)
            for a in list(args_set):
                if not a.endswith(".m3u"):
                    args_set.add(f"{a}.m3u")

            playlists = {
                (name, q, a_q)
                for name, q, a_q in self._unmatched_playlists
                if name in args_set
            }
            if not playlists:
                unmatched = [name for name, _, _ in self._unmatched_playlists]
                raise ui.UserError(
                    f"No playlist matching any of {unmatched} found"
                )

            self._matched_playlists = playlists
            self._unmatched_playlists -= playlists
        else:
            self._matched_playlists = self._unmatched_playlists

        self.__apply_opts_to_config(opts)
        self.update_playlists(lib, opts.pretend)

    def __apply_opts_to_config(self, opts: Any) -> None:
        for k, v in opts.__dict__.items():
            if v is not None and k in self.config:
                self.config[k] = v

    def _parse_one_query(
        self, playlist: dict[str, Any], key: str, model_cls: type
    ) -> tuple[PlaylistQuery, Sort | None]:
        qs = playlist.get(key)
        if qs is None:
            return None, None
        if isinstance(qs, str):
            return parse_query_string(qs, model_cls)
        if len(qs) == 1:
            return parse_query_string(qs[0], model_cls)

        queries_and_sorts: tuple[QueryAndSort, ...] = tuple(
            parse_query_string(q, model_cls) for q in qs
        )
        return queries_and_sorts, None

    def build_queries(self) -> None:
        """
        Instantiate queries for the playlists.

        Each playlist has 2 queries: one for items, one for albums, each with a
        sort. We must also remember its name. _unmatched_playlists is a set of
        tuples (name, (q, q_sort), (album_q, album_q_sort)).

        sort may be any sort, or NullSort, or None. None and NullSort are
        equivalent and both eval to False.
        More precisely
        - it will be NullSort when a playlist query ('query' or 'album_query')
          is a single item or a list with 1 element
        - it will be None when there are multiple items in a query
        """
        self._unmatched_playlists = set()
        self._matched_playlists = set()

        for playlist in self.config["playlists"].get(list):
            if "name" not in playlist:
                self._log.warning("playlist configuration is missing name")
                continue

            try:
                q_match = self._parse_one_query(playlist, "query", Item)
                a_match = self._parse_one_query(playlist, "album_query", Album)
            except ParsingError as exc:
                self._log.warning(
                    "invalid query in playlist {}: {}", playlist["name"], exc
                )
                continue

            self._unmatched_playlists.add((playlist["name"], q_match, a_match))

    def _matches_query(self, model: Item | Album, query: PlaylistQuery) -> bool:
        if not query:
            return False
        if isinstance(query, (list, tuple)):
            return any(q.match(model) for q, _ in query)
        return query.match(model)

    def matches(
        self,
        model: Item | Album,
        query: PlaylistQuery,
        album_query: PlaylistQuery,
    ) -> bool:
        if isinstance(model, Album):
            return self._matches_query(model, album_query)
        if isinstance(model, Item):
            return self._matches_query(model, query)
        return False

    def db_change(self, lib: Library, model: Item | Album) -> None:
        if self._unmatched_playlists is None:
            self.build_queries()

        for playlist in self._unmatched_playlists:
            n, (q, _), (a_q, _) = playlist
            if self.matches(model, q, a_q):
                self._log.debug("{} will be updated because of {}", n, model)
                self._matched_playlists.add(playlist)
                self.register_listener("cli_exit", self.update_playlists)

        self._unmatched_playlists -= self._matched_playlists

    def update_playlists(self, lib: Library, pretend: bool = False) -> None:
        if pretend:
            self._log.info(
                "Showing query results for {} smart playlists...",
                len(self._matched_playlists),
            )
        else:
            self._log.info(
                "Updating {} smart playlists...", len(self._matched_playlists)
            )

        playlist_dir = self.config["playlist_dir"].as_filename()
        playlist_dir = bytestring_path(playlist_dir)
        tpl = self.config["uri_format"].get()
        prefix = bytestring_path(self.config["prefix"].as_str())
        relative_to = self.config["relative_to"].get()
        if relative_to:
            relative_to = normpath(relative_to)

        # Maps playlist filenames to lists of track filenames.
        m3us: dict[str, list[PlaylistItem]] = {}

        for playlist in self._matched_playlists:
            name, (query, q_sort), (album_query, a_q_sort) = playlist
            if pretend:
                self._log.info("Results for playlist {}:", name)
            else:
                self._log.info("Creating playlist {}", name)
            items = []

            # Handle tuple/list of queries (preserves order)
            # Track seen items to avoid duplicates when an item matches
            # multiple queries
            seen_ids = set()

            if isinstance(query, (list, tuple)):
                for q, sort in query:
                    for item in lib.items(q, sort):
                        if item.id not in seen_ids:
                            items.append(item)
                            seen_ids.add(item.id)
            elif query:
                items.extend(lib.items(query, q_sort))

            if isinstance(album_query, (list, tuple)):
                for q, sort in album_query:
                    for album in lib.albums(q, sort):
                        for item in album.items():
                            if item.id not in seen_ids:
                                items.append(item)
                                seen_ids.add(item.id)
            elif album_query:
                for album in lib.albums(album_query, a_q_sort):
                    items.extend(album.items())

            # As we allow tags in the m3u names, we'll need to iterate through
            # the items and generate the correct m3u file names.
            for item in items:
                m3u_name = item.evaluate_template(name, True)
                m3u_name = sanitize_path(m3u_name, lib.replacements)
                if m3u_name not in m3us:
                    m3us[m3u_name] = []
                item_uri = item.path
                if tpl:
                    item_uri = tpl.replace("$id", str(item.id)).encode("utf-8")
                else:
                    if relative_to:
                        item_uri = os.path.relpath(item_uri, relative_to)
                    if self.config["forward_slash"].get():
                        item_uri = path_as_posix(item_uri)
                    if self.config["urlencode"]:
                        item_uri = bytestring_path(
                            pathname2url(os.fsdecode(item_uri))
                        )
                    item_uri = prefix + item_uri

                if item_uri not in m3us[m3u_name]:
                    m3us[m3u_name].append(PlaylistItem(item, item_uri))
                    if pretend and self.config["pretend_paths"]:
                        print(displayable_path(item_uri))
                    elif pretend:
                        print(item)

        if not pretend:
            # Write all of the accumulated track lists to files.
            for m3u in m3us:
                m3u_path = normpath(
                    os.path.join(playlist_dir, bytestring_path(m3u))
                )
                mkdirall(m3u_path)
                pl_format = self.config["output"].get()
                if pl_format != "m3u" and pl_format != "extm3u":
                    msg = "Unsupported output format '{}' provided! "
                    msg += "Supported: m3u, extm3u"
                    raise Exception(msg.format(pl_format))
                extm3u = pl_format == "extm3u"
                with open(syspath(m3u_path), "wb") as f:
                    keys = []
                    if extm3u:
                        keys = self.config["fields"].get(list)
                        f.write(b"#EXTM3U\n")
                    for entry in m3us[m3u]:
                        item = entry.item
                        comment = ""
                        if extm3u:
                            attr = [(k, entry.item[k]) for k in keys]
                            al = [
                                f' {key}="{quote(str(value), safe="/:")}"'
                                for key, value in attr
                            ]
                            attrs = "".join(al)
                            comment = (
                                f"#EXTINF:{int(item.length)}{attrs},"
                                f"{item.artist} - {item.title}\n"
                            )
                        f.write(comment.encode("utf-8") + entry.uri + b"\n")
            # Send an event when playlists were updated.
            send_event("smartplaylist_update")  # type: ignore

        if pretend:
            self._log.info(
                "Displayed results for {} playlists",
                len(self._matched_playlists),
            )
        else:
            self._log.info("{} playlists updated", len(self._matched_playlists))


class PlaylistItem:
    def __init__(self, item: Item, uri: bytes) -> None:
        self.item = item
        self.uri = uri