import json

import psycopg2
import psycopg2.extensions
import psycopg2.errors
import requests
import unidecode

import constants
from config import read_db_config, read_config
from log_setup import logger


class DBConnectionManager:
    def __init__(self):
        self._conn = None

    def connect(self):
        config = read_db_config()
        logger.debug("Establishing database connection with dbname={}, user={}, password={}".format(
            config.db_name, config.db_user, config.db_pass
        ))
        self._conn = psycopg2.connect("dbname='{}' user='{}' password='{}' host='localhost'".format(
            config.db_name, config.db_user, config.db_pass
        ))
        logger.debug("Established database connection.")

    def get_connection(self) -> psycopg2.extensions.connection:
        """
        Get the database connection.
        If not already connected, this reads the database config file and connects to the DB.
        Otherwise, the already active connection is returned.
        """
        if self._conn is None:
            self.connect()
        return self._conn

    def get_new_cursor(self) -> psycopg2.extensions.cursor:
        if self._conn is None:
            self.connect()
        return self._conn.cursor()


# Global instance that will hold our DB connection
conn_manager = DBConnectionManager()


def get_existing_tables():
    conn = conn_manager.get_connection()
    cur = conn.cursor()
    table_names = ", ".join("'{}'".format(tablename) for tablename in constants.DB_TABLE_NAMES)
    cur.execute(
        "SELECT tablename FROM pg_tables WHERE"
        "  schemaname = 'public' AND"
        "  tablename IN ({})".format(
            table_names
        )
    )
    return [table for (table,) in cur.fetchall()]


def init_database():
    """
    Warning: This drops all existing tables from the database
    """
    conn = conn_manager.get_connection()
    cur = conn.cursor()

    with open(constants.DATABASE_SCHEMA_PATH, "r") as f:
        cur.execute(f.read())
        conn.commit()
    logger.verbose("Initialized DB tables.")


def add_player_name(player_name: str):
    conn = conn_manager.get_connection()
    cur = conn.cursor()
    try:
        cur.execute("INSERT INTO users (player_name) VALUES (%s)", (player_name,))
        conn.commit()
    except psycopg2.errors.UniqueViolation:
        logger.warn("Player name {} already exists in the database, aborting insertion.".format(player_name))
        conn.rollback()


def add_user_name_to_player(hanabi_username: str, player_name: str):
    normalized_username = unidecode.unidecode(hanabi_username).lower()
    cur = conn_manager.get_new_cursor()
    cur.execute("SELECT id FROM users WHERE player_name = (%s)", (player_name,))
    user_id = cur.fetchone()
    if user_id is None:
        logger.error("Display name {} not found in database, cannot add username to it.".format(player_name))
        return
    else:
        cur.execute("SELECT username, player_name from user_accounts "
                    "INNER JOIN users"
                    "  ON user_accounts.user_id = users.id "
                    "WHERE "
                    "  normalized_username = (%s)",
                    (normalized_username,)
                    )
        res = cur.fetchone()
        if res is not None:
            existing_username, existing_player_name = res
            if existing_player_name == player_name:
                logger.warn("Hanabi username {} is already registered to player {}, attempted to re-register it.".format(
                    existing_username, existing_player_name
                ))
            else:
                logger.error("Hanabi username {} is already associated to player {}, cannot register it to player {}.".format(
                    res[0], res[1], player_name
                ))
            return
        cur.execute(
            "INSERT INTO user_accounts (username, normalized_username, user_id) VALUES (%s, %s, %s)",
            (hanabi_username, normalized_username, user_id)
        )
        conn_manager.get_connection().commit()


def add_player(player_name: str, user_name: str):
    add_player_name(player_name)
    add_user_name_to_player(user_name, player_name)


def fetch_and_initialize_variants():
    response = requests.get(constants.VARIANTS_JSON_URL)
    if not response.status_code == 200:
        logger.error("Could not download variants.json file from github (tried url {})".format(constants.VARIANTS_JSON_URL))
        return
    variants = json.loads(response.text)

    config = read_config()

    for variant in variants:
        variant_id = variant['id']
        name = variant['name']
        clue_starved = variant.get('clueStarved', False)
        num_suits = len(variant['suits'])

        if config.min_suit_count <= num_suits <= config.max_suit_count:
            if any(var_name in name.lower() for var_name in config.excluded_variants):
                continue
            cur = conn_manager.get_new_cursor()
            cur.execute(
                "INSERT INTO variants (id, name, num_suits, clue_starved) VALUES (%s, %s, %s, %s)",
                (variant_id, name, num_suits, clue_starved)
            )
    conn_manager.get_connection().commit()