/**
 * External dependencies
 */
import type { eventWithTime } from '@rrweb/types';

const DB_NAME = 'neliosr-events';
const DB_VERSION = 1;
const DB_STORE_NAME = 'events';

let db: IDBDatabase | undefined;

export type StoredEvent = {
	readonly id: number;
	readonly event: eventWithTime;
};

export const initEventsStore = ( callback: () => void ): void => {
	const req = indexedDB.open( DB_NAME, DB_VERSION );

	req.onupgradeneeded = function ( event: IDBVersionChangeEvent ) {
		db = ( event.target as IDBOpenDBRequest ).result;
		if ( ! db.objectStoreNames.contains( DB_STORE_NAME ) ) {
			db.createObjectStore( DB_STORE_NAME, {
				keyPath: 'id',
				autoIncrement: true,
			} );
		}
	};

	req.onerror = function ( event ) {
		// eslint-disable-next-line no-console
		console.error(
			'initEventsStore:',
			( event.target as unknown as { errorCode: unknown } ).errorCode
		);
	};

	req.onsuccess = function ( event ) {
		db = ( event.target as IDBOpenDBRequest ).result;
		callback();
	};
};

function getObjectStore( storeName: string, mode: IDBTransactionMode ) {
	if ( ! db ) {
		return undefined;
	}
	try {
		const tx = db.transaction( storeName, mode );
		return tx.objectStore( storeName );
		// eslint-disable-next-line @typescript-eslint/no-unused-vars
	} catch ( _ ) {
		return undefined;
	}
} //end getObjectStore()

export const clearEventsStore = (): void => {
	const store = getObjectStore( DB_STORE_NAME, 'readwrite' );
	if ( ! store ) {
		return;
	}
	const req = store.clear();
	req.onerror = function ( event ) {
		// eslint-disable-next-line no-console
		console.error(
			'clearObjectStore:',
			( event.target as unknown as { errorCode: unknown } ).errorCode
		);
	};
}; //end clearEventsStore()

export const saveEvent = ( event: eventWithTime ): void => {
	const store = getObjectStore( DB_STORE_NAME, 'readwrite' );
	if ( ! store ) {
		return;
	}
	const req = store.add( event );
	req.onerror = function () {
		// eslint-disable-next-line no-console
		console.error( 'saveEvent error', this.error );
	};
};

export const saveEvents = ( events: ReadonlyArray< eventWithTime > ): void => {
	const store = getObjectStore( DB_STORE_NAME, 'readwrite' );
	if ( ! store || ! events.length ) {
		return;
	} //end if

	events.forEach( ( event ) => {
		const req = store.add( event );
		req.onerror = function () {
			// eslint-disable-next-line no-console
			console.error( 'saveEvents error', this.error );
		};
	} );
};

export const peekEvents = (
	callback: ( events: ReadonlyArray< StoredEvent > ) => void
): void => {
	const store = getObjectStore( DB_STORE_NAME, 'readonly' );
	if ( ! store ) {
		return;
	}
	const events: StoredEvent[] = [];
	const req = store.openCursor();
	req.onsuccess = ( event ) => {
		const cursor = (
			event.target as unknown as {
				result: IDBCursor;
			}
		 ).result;
		if ( cursor ) {
			events.push( {
				id: cursor.primaryKey as number,
				event: ( cursor as unknown as { value: eventWithTime } ).value,
			} );
			cursor.continue();
		} else {
			callback( events );
		} //end if
	};
	req.onerror = function () {
		// eslint-disable-next-line no-console
		console.error( 'getEvents error', this.error );
	};
};

export const removeEvents = ( ids: ReadonlyArray< number > ): void => {
	const store = getObjectStore( DB_STORE_NAME, 'readwrite' );
	if ( ! store || ! ids.length ) {
		return;
	} //end if

	ids.forEach( ( id ) => {
		const req = store.delete( id );
		req.onerror = function () {
			// eslint-disable-next-line no-console
			console.error( 'removeEvents error', this.error );
		};
	} );
};