/*!
 * Copyright 2016 The ANTLR Project. All rights reserved.
 * Licensed under the BSD-3-Clause license. See LICENSE file in the project root for license information.
 */

// ConvertTo-TS run at 2016-10-04T11:26:29.5634388-07:00

import { Lexer } from "../Lexer";
import { LexerAction } from "./LexerAction";
import { LexerActionType } from "./LexerActionType";
import { MurmurHash } from "../misc/MurmurHash";
import { NotNull, Override } from "../Decorators";

/**
 * Implements the `channel` lexer action by calling
 * {@link Lexer#setChannel} with the assigned channel.
 *
 * @author Sam Harwell
 * @since 4.2
 */
export class LexerChannelAction implements LexerAction {
	private readonly _channel: number;

	/**
	 * Constructs a new `channel` action with the specified channel value.
	 * @param channel The channel value to pass to {@link Lexer#setChannel}.
	 */
	constructor(channel: number) {
		this._channel = channel;
	}

	/**
	 * Gets the channel to use for the {@link Token} created by the lexer.
	 *
	 * @returns The channel to use for the {@link Token} created by the lexer.
	 */
	get channel(): number {
		return this._channel;
	}

	/**
	 * {@inheritDoc}
	 * @returns This method returns {@link LexerActionType#CHANNEL}.
	 */
	@Override
	get actionType(): LexerActionType {
		return LexerActionType.CHANNEL;
	}

	/**
	 * {@inheritDoc}
	 * @returns This method returns `false`.
	 */
	@Override
	get isPositionDependent(): boolean {
		return false;
	}

	/**
	 * {@inheritDoc}
	 *
	 * This action is implemented by calling {@link Lexer#setChannel} with the
	 * value provided by {@link #getChannel}.
	 */
	@Override
	public execute(@NotNull lexer: Lexer): void {
		lexer.channel = this._channel;
	}

	@Override
	public hashCode(): number {
		let hash: number = MurmurHash.initialize();
		hash = MurmurHash.update(hash, this.actionType);
		hash = MurmurHash.update(hash, this._channel);
		return MurmurHash.finish(hash, 2);
	}

	@Override
	public equals(obj: any): boolean {
		if (obj === this) {
			return true;
		} else if (!(obj instanceof LexerChannelAction)) {
			return false;
		}

		return this._channel === obj._channel;
	}

	@Override
	public toString(): string {
		return `channel(${this._channel})`;
	}
}