<?php

declare(strict_types=1);

namespace LinkCheckup\Features\Scanning;

use LinkCheckup\Shared\Scan\ScanRunState;
use LinkCheckup\Shared\Scan\ScanState;
use LinkCheckup\Shared\Scan\ScanStateStore;

final class ScanControl {

	public function __construct(
		private ScanStateStore $scan_state_store,
		private ScanStarter $scan_starter,
		private ScanTransitions $transitions
	) {
	}

	public function apply( ScanAction $action ): void {
		$state = $this->scan_state_store->load();

		if ( ! $action->fits( $state->run_state ) ) {
			return;
		}

		if ( ScanAction::Start === $action ) {
			$this->scan_starter->start( $state );
			return;
		}

		$this->scan_state_store->save( $this->next_state( $action, $state ) );
	}

	private function next_state(
		ScanAction $action,
		ScanState $state
	): ScanState {
		if ( ScanAction::Cancel === $action ) {
			return $this->transitions->cancelled( $state );
		}

		$run_state = ScanAction::Pause === $action
			? ScanRunState::Paused
			: ScanRunState::Running;

		return $this->transitions->with_run_state( $state, $run_state );
	}
}