import { ApiPromise } from '@polkadot/api';
import { RequestHandler } from 'express';
import { BadRequest, InternalServerError } from 'http-errors';

import { validateAddress } from '../../middleware';
import { AccountsStakingPayoutsService } from '../../services';
import { IAddressParam } from '../../types/requests';
import AbstractController from '../AbstractController';

/**
 * GET payout information for a stash account.
 *
 * Path params:
 * - `address`: SS58 address of the account. Must be a _Stash_ account.
 *
 * Query params:
 * - (Optional) `depth`: The number of eras to query for payouts of. Must be less
 * 	than `HISTORY_DEPTH`. In cases where `era - (depth -1)` is less
 *	than 0, the first era queried will be 0. Defaults to 1.
 * - (Optional) `era`: The era to query at. Max era payout info is available for
 * 	 is the latest finished era: `active_era - 1`. Defaults to `active_era - 1`.
 * - (Optional) `unclaimedOnly`: Only return unclaimed rewards. Defaults to true.
 *
 * Returns:
 * - `at`:
 * 	- `hash`: The block's hash.
 * 	- `height`: The block's height.
 * - `eraPayouts`: array of
 * 	- `era`: Era this information is associated with.
 * 	- `totalEraRewardPoints`: Total reward points for the era.
 * 	- `totalEraPayout`: Total payout for the era. Validators split the payout
 * 			based on the portion of `totalEraRewardPoints` they have.
 * 	- `payouts`: array of
 * 		- `validatorId`: AccountId of the validator the payout is coming from.
 * 		- `nominatorStakingPayout`: Payout for the reward destination associated with the
 * 			accountId the query was made for.
 * 		- `claimed`: Whether or not the reward has been claimed.
 * 		- `totalValidatorRewardPoints`: Number of reward points earned by the validator.
 * 		- `validatorCommission`: The percentage of the total payout that the validator
 * 				takes as commission, expressed as a Perbill.
 * 		- `totalValidatorExposure`: The sum of the validator's and its nominators' stake.
 * 		- `nominatorExposure`: The amount of stake the nominator has behind the validator.
 *
 * Description:
 * Returns payout information for the last specified eras. If specifying both
 * the depth and era query params, this endpoint will return information for
 * (era - depth) through era. (i.e. if depth=5 and era=20 information will be
 * returned for eras 16 through 20). N.B. You cannot query eras less then
 * `current_era - HISTORY_DEPTH`.
 *
 * N.B. The `nominator*` fields correspond to the address being queried, even if it
 * is a validator's _stash_ address. This is because a validator is technically
 * nominating itself.
 *
 * `payouts` Is an array of payouts for a nominating stash address and information
 * about the validator they were nominating. `eraPayouts` contains an array of
 * objects that has staking reward metadata for each era, and an array of the
 * aformentioned payouts.
 *
 */
export default class AccountsStakingPayoutsController extends AbstractController<
	AccountsStakingPayoutsService
> {
	constructor(api: ApiPromise) {
		super(
			api,
			'/accounts/:address/staking-payouts',
			new AccountsStakingPayoutsService(api)
		);
		this.initRoutes();
	}

	protected initRoutes(): void {
		this.router.use(this.path, validateAddress);

		this.safeMountAsyncGetHandlers([
			['', this.getStakingPayoutsByAccountId],
		]);
	}

	/**
	 * Get the payouts of `address` for `depth` starting from the `era`.
	 *
	 * @param req Express Request
	 * @param res Express Response
	 */
	private getStakingPayoutsByAccountId: RequestHandler<
		IAddressParam
	> = async (
		{ params: { address }, query: { depth, era, unclaimedOnly } },
		res
	): Promise<void> => {
		const { hash, eraArg, currentEra } = await this.getEraAndHash(
			this.verifyAndCastOr('era', era, undefined)
		);

		const unclaimedOnlyArg = unclaimedOnly === 'false' ? false : true;

		AccountsStakingPayoutsController.sanitizedSend(
			res,
			await this.service.fetchAccountStakingPayout(
				hash,
				address,
				this.verifyAndCastOr('depth', depth, 1) as number,
				eraArg,
				unclaimedOnlyArg,
				currentEra
			)
		);
	};

	private async getEraAndHash(era?: number) {
		const [hash, activeEraOption, currentEraOption] = await Promise.all([
			this.api.rpc.chain.getFinalizedHead(),
			this.api.query.staking.activeEra(),
			this.api.query.staking.currentEra(),
		]);

		if (activeEraOption.isNone) {
			throw new InternalServerError(
				'ActiveEra is None when Some was expected'
			);
		}
		const activeEra = activeEraOption.unwrap().index.toNumber();

		if (currentEraOption.isNone) {
			throw new InternalServerError(
				'CurrentEra is None when Some was expected'
			);
		}
		const currentEra = currentEraOption.unwrap().toNumber();

		if (era !== undefined && era > activeEra - 1) {
			throw new BadRequest(
				`The specified era (${era}) is too large. ` +
					`Largest era payout info is available for is ${
						activeEra - 1
					}`
			);
		}

		return {
			hash,
			eraArg: era === undefined ? activeEra - 1 : era,
			currentEra,
		};
	}
}