import pymysql
import hashlib
from indexer.config import DB_CONFIG, ROOT_NAME


def get_connection():
    return pymysql.connect(**DB_CONFIG)


def preload_mark_all_missing():
    """
    Na začátku běhu:
    označí všechny soubory jako neexistující.
    Ty, které skener znovu najde, se přepnou zpět na exists_now = 1.
    """
    conn = get_connection()
    try:
        with conn.cursor() as cur:
            cur.execute("UPDATE files SET exists_now = 0")
        conn.commit()
    finally:
        conn.close()


def path_hash(path: str) -> bytes:
    """
    MD5 hash cesty – pouze identifikátor, ne bezpečnostní hash
    """
    return hashlib.md5(path.encode("utf-8")).digest()


def find_file_by_path(cur, path_hash_bytes):
    cur.execute(
        """
        SELECT id, file_size, mtime, content_hash
        FROM files
        WHERE path_hash = %s
        """,
        (path_hash_bytes,)
    )
    return cur.fetchone()


def insert_file(cur, file):
    cur.execute(
        """
        INSERT INTO files (
            root_name, full_path, path_hash,
            file_name, directory,
            file_size, mtime, content_hash,
            first_seen, last_seen, exists_now
        )
        VALUES (
            %s, %s, %s,
            %s, %s,
            %s, %s, %s,
            NOW(), NOW(), 1
        )
        """,
        (
            ROOT_NAME,
            file["full_path"],
            path_hash(file["full_path"]),
            file["file_name"],
            file["directory"],
            file["size"],
            file["mtime"],
            file["content_hash"],
        )
    )
    return cur.lastrowid


def update_file(cur, file_id, file):
    cur.execute(
        """
        UPDATE files
        SET file_size = %s,
            mtime = %s,
            content_hash = %s,
            last_seen = NOW(),
            exists_now = 1
        WHERE id = %s
        """,
        (
            file["size"],
            file["mtime"],
            file["content_hash"],
            file_id,
        )
    )