import json
from os.path import exists
from typing import Dict, List

from utils import id_to_url, url_to_id

db_filename = "db.json"


def init_db():
    file_exists = exists(db_filename)
    if not file_exists:
        print("Initializing json file database")
        with open(db_filename, "w") as db_file:
            db_file.write("{}")


init_db()


def _load_db():
    with open(db_filename, "r") as db_file:
        db = json.loads(db_file.read())
        return db


def _save_db(db):
    with open(db_filename, "w") as db_file:
        db_file.write(json.dumps(db, indent=4))


def get_latest_sync_time() -> int:
    db = _load_db()
    return db.get("latest_sync_time", 0)


def set_latest_sync_time(le_date) -> None:
    db = _load_db()
    db["latest_sync_time"] = le_date
    _save_db(db)


def add_discovered_url(file_url, originating_mm_post) -> List[str]:
    db = _load_db()
    files = db.get("files", {})
    file_id = url_to_id(file_url)
    if file_id not in files:
        files[file_id] = {
            "originating_mm_post_id": originating_mm_post["id"],
            "originating_mm_post_channel_id": originating_mm_post["channel_id"],
            "source_url": file_url,
        }
    db["files"] = files
    _save_db(db)
    return files


def get_files() -> List[str]:
    db = _load_db()
    files = db.get("files", {})
    return files


def set_local_file_path(file_id, local_file_path):
    db = _load_db()
    file = db["files"][file_id]
    file["local_file_path"] = local_file_path
    _save_db(db)
    return file


def mark_file_valid(file_id, metadata) -> (bool, Dict):
    """
    Return: Boolean that indicates if the file is newly identified as valid.
    """
    db = _load_db()

    file = db["files"][file_id]
    new_file = False
    if "valid" not in file or not file["valid"]:
        new_file = True
    file["valid"] = True
    file["metadata"] = metadata

    _save_db(db)

    return new_file, file


def mark_file_invalid(file_id) -> (bool, Dict):
    """
    Return: Boolean that indicates if the state is changed.
        True means it was valid but is now invalid or it was unknown and is know invalid
        False means it was invalid and is still invalid.
    """
    db = _load_db()
    file = db["files"][file_id]
    changed = False
    if "valid" not in file or file["valid"]:
        changed = True
    file["valid"] = False

    _save_db(db)

    return changed, file