import json
from typing import Dict, List, Optional

import platformdirs
import requests_cache
import psycopg2.extras

import constants
import database
from database import conn_manager
from log_setup import logger
from config import config_manager

# This ensures that we do not pose too many requests to the website, especially while in development where we
# might frequently re-initialize the database.
session = requests_cache.CachedSession(
    platformdirs.user_cache_dir(constants.APP_NAME) + 'hanab.live.requests-cache',
    urls_expire_after={
        # Game exports will never change, so cache them forever
        'hanab.live/export/*': requests_cache.NEVER_EXPIRE
    }
)


class GameInfo:
    def __init__(self, game_id: int, num_players: int, variant_id: int, seed: str, score: int, num_turns: int, user_ids: List[int], normalized_usernames: List[str]):
        self.game_id = game_id
        self.num_players = num_players
        self.variant_id = variant_id
        self.seed = seed
        self.score = score
        self.num_turns = num_turns
        self.user_ids = user_ids
        self.normalized_usernames = normalized_usernames


def fetch_games_for_player(username: str, latest_game_id: int):
    logger.verbose("Fetching games for username {} more recent than id {}".format(username, latest_game_id))
    url = "https://hanab.live/api/v1/history-full/{}?start={}".format(username, latest_game_id + 1)
    response = session.get(url)
    if not response.status_code == 200:
        err_msg = "Failed to fetch games for username {}, requested URL {}".format(username, url)
        logger.error(err_msg)
        raise ConnectionError(err_msg)
    return json.loads(response.text)


def process_game_entry(game_json: Dict, username_dict: Dict, variant_ids: List[int]) -> Optional[GameInfo]:
    logger.debug("Processing entry {}".format(game_json))
    config = config_manager.get_config()
    # Check if the game is one that we accept
    game_id = game_json["id"]
    players = game_json["playerNames"]
    num_players = len(players)
    seed = game_json["seed"]
    score = game_json["score"]
    num_turns = game_json["numTurns"]

    game_options = game_json["options"]
    var_id = game_options["variantID"]

    normalized_usernames = [database.normalize_username(username) for username in players]

    # Check that the game has no special options enabled
    for forbidden_option in constants.FORBIDDEN_GAME_OPTIONS:
        if game_options.get(forbidden_option, False):
            logger.debug("Rejected game {} due to option {} set".format(game_id, forbidden_option))
            return

    # Check if player count matches
    if not (config.min_player_count <= num_players <= config.max_player_count):
        logger.debug("Rejected game {} due to invalid number of players ({})".format(game_id, num_players))
        return

    # Check if the variant was ok
    if var_id not in variant_ids:
        logger.debug("Rejected game {} due to invalid variant id {}".format(game_id, var_id))
        return

    # Everything matches, so we can parse the participants now
    user_ids = []  # This will be a list of the (league specific) user_id's that played this game.
    for normalized_username in normalized_usernames:
        user_id = username_dict.get(normalized_username, None)
        if user_id is None:
            logger.debug("Rejected game {} due to unregistered participant {}".format(game_id, normalized_username))
            return
        user_ids.append(user_id)

    return GameInfo(game_id, num_players, 0, seed, score, num_turns, user_ids, normalized_usernames)


def fetch_games_for_all_players():
    logger.info("Fetching new games.")
    cur = conn_manager.get_new_cursor()
    cur.execute("SELECT user_accounts.normalized_username, user_accounts.user_id, downloads.latest_game_id "
                "FROM user_accounts "
                "LEFT OUTER JOIN downloads "
                "  ON user_accounts.normalized_username = downloads.normalized_username"
                )
    # This will be a mapping of normalized username -> user ID that we built from the DB data
    username_dict = {}

    # This will be a mapping of game id -> JSON data that we get from hanab.live, where we will collect all the
    # possibly relevant games now
    games: Dict[int, Dict] = {}
    for username, user_id, latest_game_id in cur.fetchall():
        username_dict[username] = user_id
        # Use the starting id as fallback if we have not downloaded any games for this player yet.
        if latest_game_id is None:
            latest_game_id = config_manager.get_config().starting_game_id

        player_games = fetch_games_for_player(username, latest_game_id)
        for game in player_games:
            games[game['id']] = game

    allowed_variants = database.get_variant_ids()

    # This will hold the processed games that we will add to the database.
    good_games: Dict[int, GameInfo] = {}

    for game_id, game in games.items():
        game_info = process_game_entry(game, username_dict, allowed_variants)
        if game_info is not None:
            good_games[game_id] = game_info

    return good_games


def store_new_games(games: Dict[int, GameInfo]):
    conn = conn_manager.get_connection()
    cur = conn.cursor()
    games_vals = []
    game_participants_vals = []
    latest_game_ids: Dict[str, int] = {}

    # Now, iterate over all games and convert to tuples for insertion
    for game in sorted(games.values(), key=lambda game_info: game_info.game_id):
        tup = (game.game_id, game.num_players, game.variant_id, game.seed, game.score, game.num_turns)
        games_vals.append(tup)
        for player_id in game.user_ids:
            tup = (game.game_id, player_id)
            game_participants_vals.append(tup)

        # Note that this gives the maximum in the end since we process the games in order
        for normalized_username in game.normalized_usernames:
            latest_game_ids[normalized_username] = game.game_id

    # Do the insertions
    # Notice that on conflict we can just do nothing: In that case, we already have the game in the DB for some reason
    # (for example, because we forced a download refresh)
    psycopg2.extras.execute_values(
        cur,
        "INSERT INTO games (id, num_players, variant_id, seed, score, num_turns) "
        "VALUES %s "
        "ON CONFLICT (id) DO NOTHING",
        games_vals
    )
    psycopg2.extras.execute_values(
        cur,
        "INSERT INTO game_participants (game_id, user_id) "
        "VALUES %s "
        "ON CONFLICT (game_id, user_id) DO NOTHING",
        game_participants_vals
    )
    # Here, we want to update on insertion conflict
    psycopg2.extras.execute_values(
        cur,
        "INSERT INTO downloads (normalized_username, latest_game_id) "
        "VALUES %s "
        "ON CONFLICT (normalized_username) "
        "DO UPDATE SET (normalized_username, latest_game_id) = (EXCLUDED.normalized_username, EXCLUDED.latest_game_id)",
        latest_game_ids.items()
    )
    # We only commit after performing all insertions. This guarantees that the download table is always in sync
    # with the actual games stored in the database.
    conn.commit()