/* eslint-disable simple-header/header */

/*!
 * idb-keyval v6.2.0
 * Copyright 2016, Jake Archibald
 * Copyright 2022, Vendicated
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

export function promisifyRequest<T = undefined>(
    request: IDBRequest<T> | IDBTransaction,
): Promise<T> {
    return new Promise<T>((resolve, reject) => {
        // @ts-ignore - file size hacks
        request.oncomplete = request.onsuccess = () => resolve(request.result);
        // @ts-ignore - file size hacks
        request.onabort = request.onerror = () => reject(request.error);
    });
}

export function createStore(dbName: string, storeName: string): UseStore {
    const request = indexedDB.open(dbName);
    request.onupgradeneeded = () => request.result.createObjectStore(storeName);
    const dbp = promisifyRequest(request);

    return (txMode, callback) =>
        dbp.then(db =>
            callback(db.transaction(storeName, txMode).objectStore(storeName)),
        );
}

export type UseStore = <T>(
    txMode: IDBTransactionMode,
    callback: (store: IDBObjectStore) => T | PromiseLike<T>,
) => Promise<T>;

let defaultGetStoreFunc: UseStore | undefined;

function defaultGetStore() {
    if (!defaultGetStoreFunc) {
        defaultGetStoreFunc = createStore("VencordData", "VencordStore");
    }
    return defaultGetStoreFunc;
}

/**
 * Get a value by its key.
 *
 * @param key
 * @param customStore Method to get a custom store. Use with caution (see the docs).
 */
export function get<T = any>(
    key: IDBValidKey,
    customStore = defaultGetStore(),
): Promise<T | undefined> {
    return customStore("readonly", store => promisifyRequest(store.get(key)));
}

/**
 * Set a value with a key.
 *
 * @param key
 * @param value
 * @param customStore Method to get a custom store. Use with caution (see the docs).
 */
export function set(
    key: IDBValidKey,
    value: any,
    customStore = defaultGetStore(),
): Promise<void> {
    return customStore("readwrite", store => {
        store.put(value, key);
        return promisifyRequest(store.transaction);
    });
}

/**
 * Set multiple values at once. This is faster than calling set() multiple times.
 * It's also atomic – if one of the pairs can't be added, none will be added.
 *
 * @param entries Array of entries, where each entry is an array of `[key, value]`.
 * @param customStore Method to get a custom store. Use with caution (see the docs).
 */
export function setMany(
    entries: [IDBValidKey, any][],
    customStore = defaultGetStore(),
): Promise<void> {
    return customStore("readwrite", store => {
        entries.forEach(entry => store.put(entry[1], entry[0]));
        return promisifyRequest(store.transaction);
    });
}

/**
 * Get multiple values by their keys
 *
 * @param keys
 * @param customStore Method to get a custom store. Use with caution (see the docs).
 */
export function getMany<T = any>(
    keys: IDBValidKey[],
    customStore = defaultGetStore(),
): Promise<T[]> {
    return customStore("readonly", store =>
        Promise.all(keys.map(key => promisifyRequest(store.get(key)))),
    );
}

/**
 * Update a value. This lets you see the old value and update it as an atomic operation.
 *
 * @param key
 * @param updater A callback that takes the old value and returns a new value.
 * @param customStore Method to get a custom store. Use with caution (see the docs).
 */
export function update<T = any>(
    key: IDBValidKey,
    updater: (oldValue: T | undefined) => T,
    customStore = defaultGetStore(),
): Promise<void> {
    return customStore(
        "readwrite",
        store =>
            // Need to create the promise manually.
            // If I try to chain promises, the transaction closes in browsers
            // that use a promise polyfill (IE10/11).
            new Promise((resolve, reject) => {
                store.get(key).onsuccess = function () {
                    try {
                        store.put(updater(this.result), key);
                        resolve(promisifyRequest(store.transaction));
                    } catch (err) {
                        reject(err);
                    }
                };
            }),
    );
}

/**
 * Delete a particular key from the store.
 *
 * @param key
 * @param customStore Method to get a custom store. Use with caution (see the docs).
 */
export function del(
    key: IDBValidKey,
    customStore = defaultGetStore(),
): Promise<void> {
    return customStore("readwrite", store => {
        store.delete(key);
        return promisifyRequest(store.transaction);
    });
}

/**
 * Delete multiple keys at once.
 *
 * @param keys List of keys to delete.
 * @param customStore Method to get a custom store. Use with caution (see the docs).
 */
export function delMany(
    keys: IDBValidKey[],
    customStore = defaultGetStore(),
): Promise<void> {
    return customStore("readwrite", (store: IDBObjectStore) => {
        keys.forEach((key: IDBValidKey) => store.delete(key));
        return promisifyRequest(store.transaction);
    });
}

/**
 * Clear all values in the store.
 *
 * @param customStore Method to get a custom store. Use with caution (see the docs).
 */
export function clear(customStore = defaultGetStore()): Promise<void> {
    return customStore("readwrite", store => {
        store.clear();
        return promisifyRequest(store.transaction);
    });
}

function eachCursor(
    store: IDBObjectStore,
    callback: (cursor: IDBCursorWithValue) => void,
): Promise<void> {
    store.openCursor().onsuccess = function () {
        if (!this.result) return;
        callback(this.result);
        this.result.continue();
    };
    return promisifyRequest(store.transaction);
}

/**
 * Get all keys in the store.
 *
 * @param customStore Method to get a custom store. Use with caution (see the docs).
 */
export function keys<KeyType extends IDBValidKey>(
    customStore = defaultGetStore(),
): Promise<KeyType[]> {
    return customStore("readonly", store => {
        // Fast path for modern browsers
        if (store.getAllKeys) {
            return promisifyRequest(
                store.getAllKeys() as unknown as IDBRequest<KeyType[]>,
            );
        }

        const items: KeyType[] = [];

        return eachCursor(store, cursor =>
            items.push(cursor.key as KeyType),
        ).then(() => items);
    });
}

/**
 * Get all values in the store.
 *
 * @param customStore Method to get a custom store. Use with caution (see the docs).
 */
export function values<T = any>(customStore = defaultGetStore()): Promise<T[]> {
    return customStore("readonly", store => {
        // Fast path for modern browsers
        if (store.getAll) {
            return promisifyRequest(store.getAll() as IDBRequest<T[]>);
        }

        const items: T[] = [];

        return eachCursor(store, cursor => items.push(cursor.value as T)).then(
            () => items,
        );
    });
}

/**
 * Get all entries in the store. Each entry is an array of `[key, value]`.
 *
 * @param customStore Method to get a custom store. Use with caution (see the docs).
 */
export function entries<KeyType extends IDBValidKey, ValueType = any>(
    customStore = defaultGetStore(),
): Promise<[KeyType, ValueType][]> {
    return customStore("readonly", store => {
        // Fast path for modern browsers
        // (although, hopefully we'll get a simpler path some day)
        if (store.getAll && store.getAllKeys) {
            return Promise.all([
                promisifyRequest(
                    store.getAllKeys() as unknown as IDBRequest<KeyType[]>,
                ),
                promisifyRequest(store.getAll() as IDBRequest<ValueType[]>),
            ]).then(([keys, values]) => keys.map((key, i) => [key, values[i]]));
        }

        const items: [KeyType, ValueType][] = [];

        return customStore("readonly", store =>
            eachCursor(store, cursor =>
                items.push([cursor.key as KeyType, cursor.value]),
            ).then(() => items),
        );
    });
}