"""Datenbankzugriff (PyMySQL) + automatisches Schema-Init.

Verwendung:
    from db import get_connection, init_db
"""
import pymysql
from pymysql.cursors import DictCursor

from config import Config


def get_connection():
    """Öffnet eine neue Verbindung zur MySQL-Datenbank."""
    return pymysql.connect(
        host=Config.DB_HOST,
        port=Config.DB_PORT,
        user=Config.DB_USER,
        password=Config.DB_PASSWORD,
        database=Config.DB_DATABASE,
        charset="utf8mb4",
        cursorclass=DictCursor,
        autocommit=True,
    )


SCHEMA = """
CREATE TABLE IF NOT EXISTS users (
    id INT AUTO_INCREMENT PRIMARY KEY,
    username VARCHAR(100) NOT NULL UNIQUE,
    email VARCHAR(255),
    salt VARCHAR(128) NOT NULL,
    password_hash VARCHAR(512) NOT NULL,
    is_admin TINYINT(1) NOT NULL DEFAULT 0,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

CREATE TABLE IF NOT EXISTS notes (
    id INT AUTO_INCREMENT PRIMARY KEY,
    user_id INT NOT NULL,
    note_date DATE NOT NULL,
    bullet_type ENUM('.', 'x', '-', '?') NOT NULL DEFAULT '-',
    note_text TEXT NOT NULL,
    priority TINYINT NOT NULL DEFAULT 0,
    status ENUM('open', 'done', 'moved') NOT NULL DEFAULT 'open',
    moved_to_date DATE NULL,
    moved_to_future TINYINT(1) NOT NULL DEFAULT 0,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
    CONSTRAINT fk_notes_user FOREIGN KEY (user_id)
        REFERENCES users(id) ON DELETE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

CREATE TABLE IF NOT EXISTS future_log (
    id INT AUTO_INCREMENT PRIMARY KEY,
    user_id INT NOT NULL,
    month_date DATE NOT NULL,
    note_text TEXT NOT NULL,
    status ENUM('open', 'done') NOT NULL DEFAULT 'open',
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    CONSTRAINT fk_future_user FOREIGN KEY (user_id)
        REFERENCES users(id) ON DELETE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
"""


def init_db():
    """Erstellt das Schema, falls es noch nicht existiert."""
    conn = get_connection()
    try:
        with conn.cursor() as cur:
            for statement in SCHEMA.split(";"):
                stmt = statement.strip()
                if stmt:
                    cur.execute(stmt)
    finally:
        conn.close()